Mechanical performance analysis of U-shaped steel-concrete composite deep coupling beam

Abstract In this paper, semi-span simply supported beam is used to simulate the mechanical behavior and failure mode of U-steel reinforced concrete composite-deep coupling beam, and three U-steel reinforced concrete composite beams, with same height-span ratio of 1/3, were tested under one-point vertical concentrated loading in mid-span. Theresults show that the mid-span yield height exceeds 60% of U-steel-concrete composite beams flange, and that the three of U-steel-concrete composite beam specimens aredamaged, there is a critical oblique crack in the inner concrete of the beam that is roughly parallel to the line between the bearing center and the loading point. It is concluded that the failure mode of this type of U-shaped steel-concrete beam begins with yieldat mid-span bottom and flanges of U-shaped steel, and ends with concrete shear failure.</jats:p

The correlation of the serum kynurenine level with P50 in first-episode patients with schizophrenia

Abstract Background: Increasing facts demonstrated the occurrence of sensory gating defects in schizophrenic sufferers, which had relation to the weakening of P50 response inhibition and had association with α7 nicotinic acetylcholine receptor (α7nAChR). Nevertheless, as a noncompetitive antagonist of α7nAChR, Kynurenic acid (KYNA) cannot cross the blood-brain barrier (BBB). In contrast, Kynurenine (KYN), as a precursor of KYNA metabolism, is capable of crossing the BBB. The exploration focused on investigatating the relation of the serum KYN level with P50 among first-episode patients with schizophrenia (FEPS).Methods: In the exploration, measurement of P50 sensory gating was conducted among 82 FEPS and 73 healthy controls (HC). Positive and Negative Syndrome Scale (PANSS) was used for assessing the psychopathology; and liquid chromatography-tandem mass spectrometry was utilized for measuring the the serum KYN level. Spearman rank correlation coefficient was used to test the correlation between P50 index and serum KYN level and PANSS score. Pearson correlation coefficient was used to test the correlation between serum KYN level and PANSS score.Results: The serum KYN levels[(251.46 ± 65.93) ng/ml vs. (320.65 ± 65.89) ng/ml, t = -6.38, p &lt; 0.001], S1 amplitude [ (2.88(1.79, 3.78) μV vs. 3.08(2.46, 4.56) μV , Z = -2.17, p =0.030] and S1 minus S2 amplitude [1.60(0.63, 2.49) μV vs. 1.92(1.12, 2.93) μV , Z = -2.23, p = 0.026] in FEPS were apparently lower than those in the HC. An obviously inverse correlation was seen between S1 minus S2 amplitude and the serum KYN levels (r = -0.32, p = 0.004) in the FEPS.</jats:p