Modification of hemp shiv properties using water-repellent sol–gel coatings

For the first time, the hydrophilicity of hemp shiv was modified without the compromise of its hygroscopic properties. This research focused on the use of sol–gel method in preparation of coatings on the natural plant material, hemp shiv, that has growing potential in the construction industry as a thermal insulator. The sol–gel coatings were produced by cohydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) using an acidic catalyst. Methyltriethoxysilane (MTES) was added as the hydrophobic precursor to provide water resistance to the bio-based material. Scanning electron microscopy (SEM) and focused ion beam (FIB) have been used to determine the morphological changes on the surface as well as within the hemp shiv. It was found that the sol–gel coatings caused a reduction in water uptake but did not strongly influence the moisture sorption behaviour of hemp shiv. Fourier transformed infrared (FTIR) spectroscopy shows that the coating layer on hemp shiv acts a shield, thereby lowering peak intensity in the wavelength range 1200–1800?cm^?1. The sol–gel coating affected pore size distribution and cumulative pore volume of the shiv resulting in tailored porosity. The overall porosity of shiv decreased with a refinement in diameter of the larger pores. Thermal analysis was performed using TGA and stability of coated and uncoated hemp shiv have been evaluated. Hemp shiv modified with sol–gel coating can potentially develop sustainable heat insulating composites with better hygrothermal properties.

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Characterization of Electroinitiated and Radiation Polymerized Poly(Butadiene Sulfone)

Polymerization of butadiene sulfone was accomplished by using two different methods. The first method involves electrochemical polymerization of the monomer using the constant potential electrolysis technique. Oxidation of the monomer under nitrogen atmosphere in an acetonitrile-tetrabutylammonium tetrafluoroborate system yields brown, tarry polymers. On the other hand, the second initiation method, which was radiation polymerization, yields white, powdery polymers. Structural analyses of the two polymers by various spectroscopic methods suggest a structure consisting of two different units in different proportions.     

Simple,inexpensive mass spectrometric analyzer for thermogravimetry

A low‐cost mass spectrometer attachment for thermogravimetric analysis has been constructed from readily available commercial instruments and components. The benefits of this set‐up include excellent mass‐flow repeatability, simple design, and significantly lower adoption cost as opposed to ready‐built commercial solutions. The inclusion of an open source software package allows semi‐automated, highly simplified data analysis. The results from the instrument show excellent sensitivity for small volumes of evolved gas, as well as highly reproducible signal strengths. The GUI‐based software package provides data analysis in a way that is very intuitive and that can be easily modified to work with a broad range of TG instruments. Copyright © 2011 John Wiley & Sons, Ltd.     

Development of a Novel Molecularly Imprinted Polyvinylimidazole/Functionalized Carbon Black Nanocomposite-based Paste Electrode for Electrochemical Sensing of Imazethapyr in Rice Samples

This paper reports the development of a simple electroanalytical method for imazethapyr (IMT) determination in rice samples based on molecularly imprinted polymer and functionalized carbon black paste electrode (MIP-fCBPE). Carbon black (CB) was functionalized by the insertion of oxygenated functional groups upon acid treatment with HNO₃ and H₂SO₄. The functionalized carbon black (fCB) presented higher performance for IMT determination than the CB without functionalization. The insertion of molecularly imprinted polyvinylimidazole (MIP-VN) in the fCBPE promoted a significant increase in the cathodic peak current even at low proportions (7.5 % w/w) due to the specific binding sites for IMT recognition. For IMT determination, DPV parameters were optimized by the Doehlert matrix applying 0.1 V for 60 s as pre-treatment in acetate buffer solution (pH 3.0) as supporting electrolyte. The proposed method showed low limit of detection (0.03 μmol L⁻¹), a wide linear range (0.10–70.00 μmol L⁻¹), and good precision in terms of repeatability of intraday measures (RSD%=3.6). The method was applied in rice samples after microwave-assisted extraction of IMT and the accuracy of the method was evaluated by addition/recovery assays (96.3–105.7 %), being statistically attested using HPLC-DAD as reference technique.     

Low field NMR for quality monitoring of 3D printed surimi from cod by-products: Effects of the pH-shift method compared with conventional washing

Implementation of three-dimensional (3D) food printing and novel analytics can reduce food waste and increase utilization of seafood by-products. Low field nuclear magnetic resonance (LF-NMR) and chemometrics were used to investigate the printability and characteristics of surimi pastes from cod by-products as affected by different processing methods (the pH-shift method vs. conventional washing), addition of salt (0, 1.5, and 3%), length of cold storage (0, 4, and 7 days) until 3D printing, and steam cooking. The analysis revealed two to three water populations in the 3D printed samples. Increasing the salt concentration induced myofibrillar swelling in the conventionally prepared surimi, whereas a more salt-induced gelling effect was observed in the pH-shift processed surimi. Cooking had a decreasing effect on the T₂₁ relaxation time and its corresponding apparent population (A₂₁), corresponding to protein denaturation and water loss during cooking. Increasing the salt concentration to 3% had a protective effect towards water exchange between the A₂₁ and A₂₃ populations in the conventionally washed samples but more subtly in the pH-shift samples. Similar trends in relaxation parameters were observed after 4 and 7 days of storage, although the intermediate population A₂₂ seemed to be most affected by the storage. Overall LF-NMR was an effective quality monitoring tool for the physicochemical changes occurring in the 3D printed surimi. The analysis showed both advantages and disadvantages of the two processing methods. However, it can clearly be concluded that increasing the salt content had a stabilizing effect on the surimi, and printing of fresh raw materials is recommended.     

Diastereoselectivity is in the Details: Minor Changes Yield Major Improvements to the Synthesis of Bedaquiline**

Bedaquiline is a crucial medicine in the global fight against tuberculosis, yet its high price places it out of reach for many patients. Herein, we describe improvements to the key industrial lithiation-addition sequence that enable a higher yielding and therefore more economical synthesis of bedaquiline. Prioritization of mechanistic understanding and multi-lab reproducibility led to optimized reaction conditions that feature an unusual base-salt pairing and afford a doubling of the yield of racemic bedaquiline. We anticipate that implementation of these improvements on manufacturing scale will be facile, thereby substantially increasing the accessibility of this essential medication.     

Heat capacity,third-law entropy,and low-temperature physical behavior of bulk hematite (α-Fe2O3)

The constant pressure heat capacity of a bulk hematite powder was measured using a Quantum Design physical properties measurement system (PPMS). The results of two series showed good precision and agreed well with measurements reported by Westrum and Grønvold. The standard molar entropy at T = 298.15 K was calculated to be (87.32 ± 2) J · mol^?1 · K^?1 for Series 1 and (87.27 ± 2) J · mol^?1 · K^?1 for Series 2, which are in good agreement with the value of (87.40 ± 0.2) J · mol^?1 · K^?1 (originally 20.889 cal · deg^?1 · mole^?1) calculated by Westrum and Grønvold. No anomaly was observed for the Morin transition, and theoretical fits below T = 15 K required a ferromagnetic T^3/2 term.