Increasing the hydrophobic interaction between terminal W-motifs enhances the stability of Salmonella typhimurium sialidase. A general strategy for the stabilization of {beta}-propeller protein fold

Protein engineering of the ß-propeller protein aimedat enhancing the structural stability of the protein was carriedout using a monomeric single domain ß-propeller protein,Salmonella typhimurium sialidase, as a model. Ala53 and Ala69each located at strands B and C of the W1 motif were mutatedto Leu and Val, respectively, to increase the hydrophobic interactionbetween W1 and W6 motifs. The mutants showed enhanced stabilitytowards guanidine hydrochloride and thermal unfolding. Ala53Leushowed higher stability, probably owing to the capability ofthe mutated Leu to interact extensively with more residues involvedin the hydrophobic interactions between the terminal W-motifs.The mutations, which are located far from the active site, haveno significant effect on the enzymatic properties. The strategyto enhance the stability proposed here might be applied to theother ß-propeller proteins.     

Physicochemical Properties,Fatty Acid Profiles,and Sensory Characteristics of Fermented Beef Sausage by Probiotics Lactobacillus plantarum IIA‐2C12 or Lactobacillus acidophilus IIA‐2B4

Probiotics may be used to enhance the functionality and nutritional values of fermented sausages. This study aims to evaluate the physicochemical and sensory properties of beef sausages fermented by lactic acid bacteria of Lactobacillus plantarum IIA‐2C12 and L. acidophilus IIA‐2B4. These strains were isolated from beef cattle and have shown to display probiotic features. While the nutrient contents were not affected by the probiotics, the pH, texture, and color varied among the sausages. Further analysis on fatty acids showed different profiles of saturated (C14:0, C17:0, and C20:0) and unsaturated (C14:1, C18:1n9c, C18:2n6c, and C22:6n3) fatty acids in sausages with probiotics. Gas chromatography–mass spectrometry further revealed some flavor development compounds including acid, alcohols, aldehydes, aromatic, ketones, sulfur, hydrocarbons and terpenes, varied among the sausages. Hedonic test showed no difference in the preference toward aroma, texture, and color for untrained panelists.     

Analgesic Effect of Tranilast in an Animal Model of Neuropathic Pain and Its Role in the Regulation of Tetrahydrobiopterin Synthesis

Trigeminal neuralgia is unilateral, lancinating, episodic pain that can be provoked by routine activities. Anticonvulsants, such as carbamazepine, are the drugs of choice; however, these possess side-effects. Microvascular decompression is the most effective surgical technique with a higher success rate, although occasionally causes adverse effects. The potential treatment for this type of pain remains unmet. Increased tetrahydrobiopterin (BH4) levels have been reported in association with axonal injury. This study aimed to evaluate the effect of tranilast on relieving neuropathic pain in animal models and analyze the changes in BH4 synthesis. Neuropathic pain was induced via infraorbital nerve constriction. Tranilast, carbamazepine, or saline was injected intraperitoneally to assess the rat’s post-intervention pain response. In the von Frey’s test, the tranilast and carbamazepine groups showed significant changes in the head withdrawal threshold in the ipsilateral whisker pad area. The motor coordination test showed no changes in the tranilast group, whereas the carbamazepine group showed decreased performance, indicating impaired motor coordination. Trigeminal ganglion tissues were used for the PCR array analysis of genes that regulate the BH4 pathway. Downregulation of the sepiapterin reductase (Spr) and aldoketo reductase (Akr) genes after tranilast injection was observed compared to the pain model. These findings suggest that tranilast effectively treats neuropathic pain.     

Synthesis of TiO2 nanoparticles at low hydrothermal temperature and its performance for DSSC sensitized using natural dye extracted from Melastoma malabathricum L. seeds

Efficiency of a dye‐sensitized solar cell (DSSC) device depends on its semiconductor layer and the sensitizing dye to absorb the light. This work seeks to obtain the best solvent for the natural dye extraction from Melastoma malabathricum L. seeds. The extracted dye is used as sensitizer on TiO₂ nanoparticles produced via hydrothermal but optimized at relatively low temperature. Infrared characterization of the extracted dyes showed differences in functional groups using different solvents, whereas ultraviolet visible examination of the dyes showed differences in intensity along the spectrum ranges of 600 to 400 nm with maximum absorption around 550 to 500 nm. Thermal analysis revealed that the natural dye should be stable around room temperature. Analysis on the synthesized TiO₂ nanoparticles showed that the average crystallite size reported in the previous work is consistent with crystallite sizes observed in the transmission electron microscope images. Photoactivity examination showed that the DSSC sensitized using natural dye extracted with ethanol containing 20% distilled water on TiO₂ synthesized at 150°C has an efficiency of 5.7%, whereas the one on commercial TiO₂ P25 Degussa has an efficiency of 3.0%. The DSSC device sensitized using commercial dye on TiO₂ synthesized at 150°C has an efficiency of 4.4%, whereas the one on TiO₂ P25 Degussa has an efficiency of 4.0%. This result is promising for further development of the DSSC device using TiO₂ nanoparticles synthesized at low hydrothermal temperature and sensitized with the natural dye.     

Sustainability trends in the process industries: A text mining-based analysis

Sustainability is widely recognized as one of the most important challenges facing the world today. Companies publish sustainability reports that present their efforts and achievements in meeting sustainability goals and targets. In this paper, text mining is used to identify sustainability trends and practices in the process industries. Four main sectors of the industry are studied: oil/petrochemicals, bulk/specialty chemicals, pharmaceuticals, and consumer products. Our study reveals that the top sustainability focuses of the four sectors are very similar: health and safety, human rights, reducing GHG, conserving energy/energy efficiency, and community investment. Sector-specific sustainability issues have also been identified, for example oil spill prevention in the oil/petrochemicals sector and access to medicine in the pharmaceuticals sector. Environment is identified to be the predominant sustainability aspect in the process industries. The text mining methodology, results, and findings are detailed in the paper.     

Investigating the Potential of Using Off-Axis 3D Woven Composites in Composite Joints’ Applications

The effect of circular notch has been evaluated for three different architectures of three-dimensional (3D) carbon fibre woven composites (orthogonal, ORT; layer-to-layer, LTL; angle interlock, AI) through open-hole quasi-static tension and double-lap bearing strength tests in the off-axis (45°) direction. Damage characterisation is monitored using Digital Image correlation (DIC) for open-hole testing and X-ray Computed Tomography (CT) for double-lap bearing strength test. The off-axis notched 3D woven composites exhibits minor reduction (less than 10 %) of the notched strength compared to the un-notched strength. DIC strain contour clearly show stress/strain localisation regions around the hole periphery and stress/strain redistribution away from the whole due to the z-binder existence, especially for ORT architecture. Up to 50 % bearing strain, no significant difference in the bearing stress/bearing strain response is observed. However when ORT architecture was loaded up to failure, it demonstrates higher strain to failure (~140 %) followed by AI (~105 %) and lastly LTL (~85 %). X-ray CT scans reveal the effect of the z-binder architecture on damage evolution and delamination resistance. The study suggests that off-axis loaded 3D woven composites, especially ORT architecture, has a great potential of overcoming the current challenges facing composite laminates when used in composite joints’ applications.     

Study of microcellular foaming of polystyrene aided with 45 kHz of ultrasound waves energy

ABSTRACT

In the microcellular foam plastic processing, cellular formation stage was being an essential stage since the nucleation and growth of the cell take place within. Based on classical nucleation theory, diminution of the free energy for nucleation, exponentially lead to an increase in the nucleation rate. This can be done by increasing the super-saturation level which achieved by heating the gas-saturated polymer. Hence, the advance is taken out by utilizing the ultrasound wave simultaneously with heating for foaming Polystyrene-scCO₂, which, not only to keep the super-saturation degree but also reduce the nucleation barrier. In this work, foaming was conducted under 45 kHz of ultrasound and varying the foaming temperature after saturating polystyrene with scCO₂. The results demonstrate, that foaming under ultrasound, the expansion ratio attained up to 1.5 fold, increase along with the heating temperature. Higher cell densities obtained with ultrasound applied at 50°C, however only slight difference can be seen, which about 10¹⁰–10¹¹ cell/cm³. From the cell size distribution results, cell distributed around 0.5–3.5 µm, with or without ultrasound applied for 60 and 70°C, Meanwhile at 50°C of foaming, the lowest cell size obtained with the aid of ultrasound in the range of 0.3–2.4 µm.     

A DNA microarray for fission yeast: minimal changes in global gene expression after temperature shift

Completion of the fission yeast genome sequence has opened up possibilities for post-genomic approaches. We have constructed a DNA microarray for genome-wide gene expression analysis in fission yeast. The microarray contains DNA fragments, PCR-amplified from a genomic DNA template, that represent > 99% of the 5000 or so annotated fission yeast genes, as well as a number of control sequences. The GenomePRIDE software used attempts to design similarly sized DNA fragments corresponding to gene regions within single exons, near the 3'-end of genes that lack homology to other fission yeast genes. To validate the design and utility of the array, we studied expression changes after a 2 h temperature shift from 25 degrees C to 36 degrees C, conditions widely used when studying temperature-sensitive mutants. Obligingly, the vast majority of genes do not change more than two-fold, supporting the widely held view that temperature-shift experiments specifically reveal phenotypes associated with temperature-sensitive mutants. However, we did identify a small group of genes that showed a reproducible change in expression. Importantly, most of these corresponded to previously characterized heat-shock genes, whose expression has been reported to change after more extreme temperature shifts than those used here. We conclude that the DNA microarray represents a useful resource for fission yeast researchers as well as the broader yeast community, since it will facilitate comparison with the distantly related budding yeast, Saccharomyces cerevisiae. To maximize the utility of this resource, the array and its component parts are fully described in On-line Supplementary Information and are also available commercially.