Biomechanical Strategies Underlying the Robust Body Armour of an Aposematic Weevil

Robust body armor is one of many anti-predator strategies used among animal taxa. The exoskeleton of insects can serve as the secondary defense mechanism in combination with the primary defense such as warning color. Aposematic Pachyrhynchus weevils advertise their unprofitability and use their robust exoskeleton for effective defense against lizard predators. While the mature weevils survive after the predatory attack, the soft teneral ones can easily be consumed. To reveal how the mature weevils achieve such effective protection, we investigated the ontogenetic changes in the microstructure and material properties of the exoskeleton of the adult weevils. We also tested the functional role of a weevil-specific structure, the fibrous ridge, in the robustness of the elytral cuticle of the mature weevils. The results showed that the mature weevils have thicker, stiffer and more sclerotized cuticle than the teneral ones. The fibrous ridges in the endocuticle considerably increase the overall stiffness of their cuticle. Together these biomechanical strategies enable Pachyrhynchus weevils to achieve robust body armor that efficiently protects them from lizard predation

Improved microstructure and mechanical properties of sheet metals in ultrasonic vibration enhanced biaxial stretch forming

Ultrasonic energy is used for applying severe plastic deformation on metal surfaces. In the present work, the effect of ultrasonic vibration on the formability, microhardness and microstructural properties of St14 steel sheet has been investigated. To be precise, a semi-hemispherical-head forming tool had shaped the specimens until the necking started to happen. Conventional as well as the ultrasonic-assisted biaxial stretch forming test has been performed on St14 steel sheets and obtained data has been used to compare the hardness and microstructure of the specimen with and without superimposing the ultrasonic vibration. It was observed that the hardness of the samples which have been shaped by applying ultrasonic vibrations to the tool with an amplitude of 15µm at 20.5 kHz increased significantly in compared with the samples which have been shaped without using ultrasonic vibration, revealing the efficiency of the ultrasonic operation in increasing the hardness.</span

The driving forces of energy consumption and carbon dioxide emissions in Iran's electricity sector: A decomposition analysis based on types of ownership

As the most active industry, the electricity generation sector contributes 22% of Iran's total energy consumption and 31% of Carbon dioxide (CO2) emissions. While power plants' high pollution and increasing power demand have prioritized determining energy consumption and emissions' underlying factors, there is no comprehensive study to analyze these factors in Iran's power sector yet. To identify driving factors of energy consumption and CO2 emissions, we utilize the Logarithmic Mean Divisia Index (LMDI) to investigate the effects of activity, generation structure, energy intensity, fuel-mix, and fuel emission coefficient on both variables between 1990 and 2017. While Decomposition studies are mostly analyses economic sectors based on the type of infrastructure, with a novel approach, we decomposed the driving factors based on the power plants' ownership to investigate how privatization affects them. This research confirmed that the activity factor was mainly responsible for both variables' growth, with a contribution ratio of more than 110% over their total amount. In contrast, the energy intensity factor reduced them by almost 12%, mainly due to the private sector's greater efficiency. It has also been stated that the private sector had a lower pollution rate, and the privatization policy has helped to reduce energy intensity and pollution

Dethioacylation by sirtuins 1–3: Considerations for drug design using mechanism-based sirtuin inhibition

[Image: see text] The sirtuin enzymes are potential drug targets for intervention in a series of diseases. Efforts to inhibit enzymes of this class with thioamide- and thiourea-containing, substrate-mimicking entities have produced a number of high-affinity binders. However, less attention has been dedicated to the investigation of the stability of these inhibitors under various conditions. Here, we provide evidence of an unprecedented degree of cleavage of short-chain ε-N-thioacyllysine modifications meant to target these sirtuins and further provide insights into the serum stability of compounds containing both thioamides and thioureas. Our study questions the utility short-chain thioamide-based inhibitors of sirtuins for drug development and points to monoalkylated thiourea-based chemotypes as being more stable in human serum