Simulation study on the effect of resistance exercise on the hydrodynamic microenvironment of osteocytes in microgravity.

Osteoporosis occurs in astronauts after long-term space flight owing to the lack of gravity. The mechanical microenvironment of osteocytes in load-bearing bone are changed during resistance exercise, which prevents massive bone loss in the human body. A cylindrical fluid-structure coupling finite element model for osteons with a two-stage pore structure (i.e., Haversian canal, lacunar-canalicular system) was established with the software COMSOL. In the Earth's gravity field and in microgravity, considering the effects of pulsating pressure of arterioles, a comparative study was performed on the changes in hydrodynamic microenvironment of osteocytes during human body high-intensity exercise at different frequencies (defined as causing bone to produce 3000 µÎµ) and the body is at rest. Positive and negative liquid pressure (with respect to one atmosphere pressure) alternately acted on osteocytes during human exercising, but only positive pressure acted on osteocytes during human resting. The variation range of liquid pressure acted on osteocytes during human exercising was significantly higher than that during resting. The liquid flow velocity around osteocytes during body exercise was about four orders of magnitude higher than that during resting. In microgravity, moderate physical exercise can obviously improve the hydrodynamic microenvironment of osteocytes in load-bearing bone, which could compensate for the lack of mechanical stimulation to osteocytes caused by the lack of gravity, thereby promoting the normal physiological function of osteocytes. To a certain extent, these results revealed the biomechanical mechanism by which exercise has an effect in fighting osteoporosis in astronauts.

Corrosion Behavior of AISI 316L Stainless Steel Used as Inner Lining of Bimetallic Pipe in a Seawater Environment.

Seawater leakage commonly leads to corrosion in the inner lining of submarine bimetallic pipes, with significant financial implications for the offshore oil and gas production industry. This study aims to improve understanding of the performance of bimetallic pipes by investigating the corrosion behaviors of mechanically bonded 316L stainless steel. Immersion experiments were conducted in a seawater environment, under both atmospheric conditions and high temperature and high pressure conditions, and corroded surfaces were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to reveal micromorphology and elementary compositions. The results demonstrated that the corrosion rates of the bonded 316L specimen were between 5% and 20% higher than those of specimens without bonding under atmospheric conditions. This is attributed to the stress cracking that occurs during corrosion. Under high temperature and high pressure conditions, the corrosion rates were remarkably increased (91% to 135%) and the corrosion process took longer to reach equilibrium. This may be attributed, firstly, to the products becoming increasingly porous and weak, and also to the fluid stress caused by stirring in these experiments to simulate seawater movement.

Corrigendum to "Interleukin-9 Deletion Relieves Vascular Dysfunction and Decreases Blood Pressure via the STAT3 Pathway in Angiotensin II-Treated Mice".

[This corrects the article DOI: 10.1155/2020/5741047.].

Interleukin-9 Deletion Relieves Vascular Dysfunction and Decreases Blood Pressure via the STAT3 Pathway in Angiotensin II-Treated Mice.

BACKGROUND: Multiple interleukin (IL) family members were reported to be closely related to hypertension. We aimed to investigate whether IL-9 affects angiotensin II- (Ang II-) induced hypertension in mice. METHODS: Mice were treated with Ang II, and IL-9 expression was determined. In addition, effects of IL-9 knockout (KO) on blood pressure were observed in Ang II-infused mice. To determine whether the effects of IL-9 on blood pressure was mediated by the signal transducer and activator of the transcription 3 (STAT3) pathway, Ang II-treated mice were given S31-201. Furthermore, circulating IL-9 levels in patients with hypertension were measured. RESULTS: Ang II treatment increased serum and aortic IL-9 expression in a dose-dependent manner; IL-9 levels were the highest in the second week and continued to remain high into the fourth week after the treatment. IL-9 KO downregulated proinflammatory cytokine expression, whereas it upregulated anti-inflammatory cytokine levels, relieved vascular dysfunction, and decreased blood pressure in Ang II-infused mice. IL-9 also reduced smooth muscle 22α (SM22α (SM22. CONCLUSIONS: IL-9 KO alleviates inflammatory response, prevents phenotypic transformation of smooth muscle, reduces vascular dysfunction, and lowers blood pressure via the STAT3 pathway in Ang II-infused mice. IL-9 might be a novel target for the treatment and prevention of clinical hypertension.

2-(4-Formylphenyl)phenanthroimidazole as a colorimetric and fluorometric probe for selective fluoride ion sensing.

An easy-to-prepare chemosensor, 2-(4-formylphenyl)phenanthroimidazole 1, synthesized by facile one-step condensation under microwave irradiation, has been indicated to be a colorimetric and fluorometric probe for fluoride anion with good sensitivity and high selectivity. This probe shows obvious red shift and absorbance intensity changes in UV absorption and fluorescence spectra in the presence of fluoride anions. Such color and absorbance intensity changes are attributed to the deprotonation of N-H on the imidazole moiety with fluoride anion.

Fe-catalyzed highly selective ring expansion of alkynylcyclopropyl alkanols to cyclobutanols.

A Fe-catalytic highly selective ring expansion reaction of alkynylcyclopropyl alkanols to alkynylcyclobutanols via a 1,2-carbon shift under mild conditions was developed. A new class of homogeneous FeCl(2)/O(2) catalytic system was employed in these novel transformations.

2-(4-Methoxy-phen-yl)phenanthro[9,10-d]imidazole methanol solvate.

The title compound, C(22)H(16)N(2)O·CH(4)O, is a product of the condensation reaction between phenanthrene-quinone and 4-methoxy-benzadehyde. There are two imidazole mol-ecules and two methanol molecules in the asymmetric unit. The phenanthryl and imidazole rings are almost parallel in both mol-ecules, with inter-planar angles of 6.65 (1) and 5.40 (3)°. The dihedral angles between the imidazole and the attached benzene rings are 5.40 (3) and 6.65 (1)° in the two molecules. Inter-molecular O-H⋯N and N-H⋯O hydrogen bonds stabilize the crystal packing.

Dimethyl 4-(4-formyl-phen-yl)-2,6-di-methyl-1,4-dihydro-pyridine-3,5-dicar-boxyl-ate.

The title compound, C(18)H(19)NO(5), is a product of the Hantzsch reaction of p-phthalaldehyde, methyl acetoacetate, and ammonium acetate. The 1,4-dihydro-pyridine ring of the mol-ecule adopts a flattened boat conformation. The benzene ring is almost perpendicular to the 1,4-dihydro-pyridine ring; the plane through the six C atoms of the benzene ring and the plane through the four C atoms that form the base of the boat-shaped 1,4-dihydro-pyridine ring (excluding the ring N atom and the opposite ring C atom) make a dihedral angle of 87.60 (3)°. Inter-molecular N-H⋯O hydrogen bonds result in the formation of extended chains along the a axis.

2,2'-(1,2-Ethanediyldithio)bis(1,3-benzothiazole).

In the title compound, C(16)H(12)N(2)S(4), which is the result of the S-alkylation reaction of 2-mercaptobenzothiazole with ethylene dibromide, the planes of the two benzothiazole moieties form a dihedral angle of 3.84 (14) degrees. The bridging chain moiety, -SCH(2)CH(2)S-, adopts an antiperiplanar conformation. There are intermolecular S.S non-bonded contacts of 3.6471 (9) A, which stabilize the crystal packing.

4,5,9,10-tetrahydro-4-methyl-2-phenyl-9,10-epoxy-3H,10aH-cyclobuta[a]benzo[2,3,4-de]isoquinoline-3,5-dione.

In the title compound, C(21)H(15)NO(3), which is one of the photoreaction products of N-methyl-1,8-naphthalenedicarboximide with phenylacetylene, the cyclobutene and epoxy rings are trans to each other across the cyclohexene ring of the tetralin moiety. The dihedral angle between the mean planes of the cyclobutene and cyclohexene rings is 112.80 (2) degrees, while the latter makes a dihedral angle of 103.70 (9) degrees with the epoxy ring. The crystal structure is stabilized by C-H...O intermolecular interactions.