One Amino Acid Change of Angiotensin II Diminishes Its Effects on Abdominal Aortic Aneurysm

Angiotensin (Ang) A is formed by the decarboxylation of the N terminal residue of AngII. The present study determined whether this one amino acid change impacted effects of AngII on abdominal aortic aneurysm (AAA) formation in mice. Computational analyses implicated that AngA had comparable binding affinity to both AngII type 1 and 2 receptors as AngII. To compare effects of these two octapeptides in vivo, male low-density lipoprotein receptor (Ldlr) or apolipoprotein E (Apoe) deficient mice were infused with either AngII or AngA (1 μg/kg/min) for 4 weeks. While AngII infusion induced AAA consistently in both mouse strains, the equivalent infusion rate of AngA did not lead to AAA formation. We also determined whether co-infusion of AngA would influence AngII-induced aortic aneurysm formation in male Apoe−/− mice. Co-infusion of the same infusion rate of AngII and AngA did not change AngII-induced AAA formation. Since it was reported that a 10-fold higher concentration of AngA elicited comparable vasoconstrictive responses as AngII, we compared a 10-fold higher rate (10 μg/kg/min) of AngA infusion into male Apoe−/− mice with AngII (1 μg/kg/min). This rate of AngA led to abdominal aortic dilation in three of ten mice, but no aortic rupture, whereas the 10-fold lower rate of AngII infusion led to abdominal aortic dilation or rupture in eight of ten mice. In conclusion, AngA, despite only being one amino acid different from AngII, has diminished effects on aortic aneurysmal formation, implicating that the first amino acid of AngII has important pathophysiological functions

Disorder and diffuse scattering in single-chirality (TaSe4_4)2_2I crystals

The quasi-one-dimensional chiral compound (TaSe$_4$)$_2$I has been extensively studied as a prime example of a topological Weyl semimetal. Upon crossing its phase transition temperature $T_\textrm{CDW}$ $\approx$ 263 K, (TaSe$_4$)$_2$I exhibits incommensurate charge density wave (CDW) modulations described by the well-defined propagation vector $\sim$(0.05, 0.05, 0.11), oblique to the TaSe$_4$ chains. Although optical and transport properties greatly depend on chirality, there is no systematic report about chiral domain size for (TaSe$_4$)$_2$I. In this study, our single-crystal scattering refinements reveal a bulk iodine deficiency, and Flack parameter measurements on multiple crystals demonstrate that separate (TaSe$_4$)$_2$I crystals have uniform handedness, supported by direct imaging and helicity dependent THz emission spectroscopy. Our single-crystal X-ray scattering and calculated diffraction patterns identify multiple diffuse features and create a real-space picture of the temperature-dependent (TaSe$_4$)$_2$I crystal structure. The short-range diffuse features are present at room temperature and decrease in intensity as the CDW modulation develops. These transverse displacements, along with electron pinning from the iodine deficiency, help explain why (TaSe$_4$)$_2$I behaves as an electronic semiconductor at temperatures above and below $T_\textrm{CDW}$, despite a metallic band structure calculated from density functional theory of the ideal structure.Comment: 24 pages, 20 figures, 3 table

Reexamination of Romantic Red Effect Based on the Findings of Elliot et al 2010

As a group project of "Methods of Psychological Experiment" course work, we (7 of us) are going to reexamine the Romantic Red Effect published on “Journal of Experimental Psychology: General” by Elliot et al in 2010

Preparation and characterization of oriented hydroxyapatite bundles in supersaturated solution: conic interference and charge balance

Hydroxyapatite (HA), an artificial bioceramic with high similarity to the mineral constituent of vertebrate bones and teeth, has attracted extensive attention due to its excellent bioactivity and biocompatibility. The micro-nano structure of HA is a vital factor in expanding its application in biomedicine as well as in many other industrial fields. What's more, HA nanofiber exhibits outstanding properties among its various morphologies. In this work, HA bundles with the same oriented nanofibers are successfully synthesized in a solvothermal reaction system by controlling the amount of carbonate addition and using oleic acid as a template. Under the synergistic effect of different molar ratios of hydroxide ion to carbanion ([OH−]/[CO32−]), HA nanofibers gradually increase their aspect ratio and tend to grow into oriented bundles. This product has admirable flexibility and good mechanical strength, as well as great application potential. Based on the characterization and analysis results, we take a further exploration of the effects of ionic interference ([OH−]/[CO32−]) and charge balance (CO32− vs PO43, Na + vs Ca2+) on the microstructure, phase composition and thermal stability of HA nanofibers bundles (HANBs) in the solvothermal system during the chemical reaction process. And then, the formation and assembly mechanism of HANBs is proposed, and the role of van der Waals forces in this process is also discussed. Furthermore, the generation of this clustered state may be influenced by the shift in the dissolution equilibrium of insoluble carbonates during synthesis. This research provides a new direction for controlling the micro-nano morphology of HA to further obtain products with desirable properties

Nicotine Accelerates Atherosclerosis in Apolipoprotein E–Deficient Mice by Activating α7 Nicotinic Acetylcholine Receptor on Mast Cells

Objective-Cigarette smoking is an independent risk factor for atherosclerosis. Nicotine, the addictive component of cigarettes, induces mast cell (MC) release and contributes to atherogenesis. The purpose of this study was to determine whether nicotine accelerates atherosclerosis through MC-mediated mechanisms and whether MC stabilizer prevents this pathological process. Approach and Results-Nicotine administration increased the size of atherosclerotic lesions in apolipoprotein E-deficient (Apoe(-/-)) mice fed a fat-enriched diet. This was accompanied by enhanced intraplaque macrophage content and lipid deposition but reduced collagen and smooth muscle cell contents. MC deficiency in Apoe(-/-) mice (Apoe(-/-)Kit(W-sh/W-sh)) diminished nicotine-induced atherosclerosis. Nicotine activated bone marrow-derived MCs in vitro, which was inhibited by a MC stabilizer disodium cromoglycate or a nonselective nicotinic acetylcholine receptor blocker mecamylamine. Further investigation revealed that alpha 7 nicotinic acetylcholine receptor was a target for nicotine activation in MCs. Nicotine did not change atherosclerotic lesion size of Apoe(-/-)Kit(W-sh/W-sh) mice reconstituted with MCs from Apoe(-/-)alpha 7 nAChR(-/-) animals. Conclusions-Activation of alpha 7 nicotinic acetylcholine receptor on MCs is a mechanism by which nicotine enhances atherosclerosis