AFM-based force spectroscopy measurements of mature amyloid fibrils of the peptide glucagon

We report on the mechanical characterization of individual mature amyloid fibrils by atomic force microscopy (AFM) and AFM-based single-molecule force spectroscopy (SMFS). These self-assembling materials, formed from the 29-residue amphiphatic peptide hormone glucagon, were found to display a reversible elastic behaviour. Based on AFM morphology and SMFS studies, we suggest that the observed elasticity is due to a force-induced conformational transition which is reversible due to the β-helical conformation of protofibrils, allowing a high degree of extension. The elastic properties of such mature fibrils contribute to their high stability, suggesting that the internal hydrophobic interactions of amyloid fibrils are likely to be of fundamental importance in the assembly of amyloid fibrils and therefore for the understanding of the progression of their associated pathogenic disorders. In addition, such biological amyloid fibril structures with highly stable mechanical properties can potentially be used to produce nanofibres (nanowires) that may be suitable for nanotechnological applications.     

Effect of microwave heating duration on the stability of the partially stabilised zirconia doped with CaO

In this paper, the stability of CaO doped partially stabilised zirconia (CaO-PSZ) prepared by electrofusion method was improved from 88.14% to 95% within 1 h using the microwave heating method. The increase of the stability rate was because of the microwave heating method's advantages, including selective heating and fast heating. Analysis techniques, namely X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM), were used to analysis the influences of the holding time (1–4 h) on the CaO doped PSZ samples at a heating temperature of 1100 °C to understand the fundamental mechanism of the optimisation process. The Raman and XRD spectra were fitted by the Gaussian method to further analysis the effect of holding time on the microstructure evolution of the samples. The fitting results indicated that the sample's crystal quality and stability were improved after microwave heating, and the optimised holding time is 2 h.     

Flow characteristics of xanthan solutions and their crude oil emulsions in terms of thixotropic behavior

The thixotropic characteristics of xanthan solutions and their emulsions with crude oil were investigated experimentally. Understanding these characteristics are required for the crude oil displacement mechanism by polymer solution during the enhanced oil recovery phase. RS100 rheometer with a cone and plate device was employed for this examination using controlled-rate mode. Two crude oil concentrations of 25% and 75% by volume were examined. A wide range of xanthan gum concentration of 500–10⁴ ppm was covered. This study results that the aqueous solutions of xanthan gums showed thixotropic behavior. The high concentrations of xanthan solutions provide higher hysteresis loop than the solutions of lower concentrations. The existence of crude oil within the xanthan emulsions considerably elevates the thixotropic rheograms profile.     

Technical and economical/financial feasibility analyses of flared gas recovery in Egypt from oil and gas industry from international/national oil companies’ perspectives

Egypt is an importer of energy, yet 5.7 MMSCM (200 MMSCF) of natural gas is flared every day and causes a negative environmental impact. Recovery of such significant amount is crucial and accordingly there are three alternative solutions to recover these gases, namely LPG/condensate extraction, recycling, or power generation. These alternatives were studied technically, financially, and economically, and results indicate that investors’ orientation and vision play a vital role in decision making especially when production sharing agreement is applied. The conflict of interest among investors was tackled and applied on a case study from different perspectives. Results indicate that the added value itself differs from one investor to another. In the case studied, international oil companies “IOCs” prefer recycling to achieve reasonable net present value “NPV” up to $40 million. National oil companies “NOCs” prefer generating power to achieve maximum net value added “NVA” up to $58 million, to maximize the environmental and social added value. The least feasible option is extracting LPG/condensate from the flared gas although Egypt is LPG importer. The conflict of interest and current oil prices are the reasons behind postponing such projects. So, Egyptian government should impose policies to reduce flared gas emissions and maximize benefits through these projects and this can be done by compromising with “IOCs” to ensure maximum financial/social benefits.     

Plasmonic Metaparticles on a Blackbody Create Vivid Reflective Colors for Naked‐Eye Environmental and Clinical Biodetection

Plasmonic dipoles are famous for their strong absorptivity rather than their reflectivity. Here, the as‐yet unknown specular reflection and the Brewster effect of ultrafine plasmonic dipoles, metaparticles, are introduced and exploited as the basis of new design rules for advanced applications. A configuration of “Plasmonic metaparticles on a blackbody” is demonstrated and utilized for the design of a tailored perfect‐colored absorber and for visual detection of environmental dielectrics that is not readily done by extinction plasmonics. Moreover, the Plasmonic Brewster Wavelength (PBW) effect is introduced as a new platform for the naked‐eye and bulk biodetection of analytes. The technique operates based on slight changes of molecular polarizability which is not detectable via conventional plasmon resonance techniques. As a specific highlight, the clinical applicability of the PBW method is demonstrated while addressing the transduction plasmonic techniques' challenge in detection of bulk refractive index changes of the healthy and diseased human serum exosomes. Finally, the sputtering‐based fabrication method used here is simple, inexpensive, and scalable, and does not require the sophisticated patterning approach of lithography or precise alignment of light coupling for the biodetection.     

Research on microwave drying technology in the procedure of preparation of V2O5 from ammonium polyvanadate (APV)

High-quality vanadium pentoxide powder is an important product of the vanadium industry and was usually prepared from ammonium polyvanadate (APV) using a roasting process combined with a drying pretreatment. Conventional hot air drying is usually used for the drying of APV, the heat transfer of which is from outside to inside thus limited the efficiency of the drying pretreatment. In the present paper, microwave heating was applied as an alternative heating method for the drying of APV because of its advantages including selective heating, high heating efficiency, low energy consumption, and green environmental protection. An experimental comparison between hot air drying and microwave drying is provided, and the results show that microwave drying is more energy-saving and faster. The drying characteristics of APV under the irradiation of microwave energy were investigated. The influences of factors including microwave power, material quality, and initial moisture content on microwave drying were studied. The results show that the microwave power, initial moisture content, and initial mass are positively proportional to the microwave drying efficiency of APV. Additionally, the Page model was robust in describing the kinetics of microwave drying and hot air drying of APV. This study provides fundamental knowledge on the microwave drying process and provides the trial for the industrial applications of microwave heating on the preparation of V₂O₅.     

Production of ultra-high strength wire rod steels by vanadium microalloying

Ultra-high strength high-carbon wire rod steels have been produced using vanadium-microalloying technique instead of the conventional expensive and environment polluting lead patenting treatment. The strength increment attained in the hot rolled steels due to vanadium additions is maintained in the cold drawn wire. By using this technique, high tensile strength levels of 1550-1600 N/mm² were attained either by cold drawing of 0.17% V microalloyed high-carbon steel to 45-47% reduction or by cold drawing of 0.20% V microalloyed high-carbon steel to 25-30% reduction. An equation has been developed to predict the tensile strength from the chemical composition, cooling rate and reduction of area due to cold drawing. A combination of vanadium microalloying and accelerated cooling resulted in additional strength increment due to refining of microstructure and increasing the precipitation strengthening component. Inspite of the decrease in the amount of vanadium precipitates due to the increase in cooling rate, it is suggested that an increase in precipitation strengthening due to refining of these precipitates by accelerated cooling more than offsets the loss of precipitation strengthening due to decreasing the precipitates fraction.     

Experimental investigation of the yield stress measurements for xanthan solutions and crude oil-xanthan emulsions

Yield stress measurements of xanthan aqueous solutions and crude oil-xanthan emulsions were investigated experimentally. The yield stress study was carried out for wide range of crude oil (0–75% by volume) and xanthan gum (0–10⁴ ppm) concentrations. Two types of xanthan polymers of Sigma and Kelzan were used for the current study. Aqueous solutions with higher xanthan concentration displayed higher cycles of shear rate-shear stress rheograms. Both aqueous solutions of Sigma and Kelzan showed similar behavior for concentration of ≤1000 ppm, however, Sigma solutions of higher concentrations reported slightly higher flow behavior than Kelzan. Similar rheogram behaviors are found for both Sigma and Kelzan emulsions up to concentration of 5,000 ppm. However, for 10,000 ppm, a slight higher profile for Sigma emulsions was reported.