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High-fill culverts placed in valley topography have a complex earth pressure distribution law due to their locations around culverts in various valley topography conditions. In order to investigate the influence of valley topography on the earth pressure around the culvert of high-fill arch culverts, an interaction model of "topography-culvert-fill" was established by using centrifugal model test and numerical simulation method. Additionally, the distribution laws of earth pressure around the arch culverts and earth pressure concentration coefficient Ks at the top of the culvert under different valley widths B and valley slopes α were analyzed and were compared with the latest Chinese culvert design code. Furthermore, the mechanism of earth pressure formation of high-fill arch culverts under valley topography was presented. The research findings are as follows: (1) The influence of the valley width B on the earth pressure concentration coefficient Ks at the top of the culvert is significant, and the increment of the earth pressure concentration coefficient Ks at the top of the culvert is larger when B is 4D−6D（D is the clear span of arch culvert）. (2) When B is less than 4D, the topography would play the role of load reduction to the culvert. (3) With valley slopes ranging from 45° to 60°, the earth pressure at the tops and Ks would be affected dramatically. (4) When fill height is 20 m with α >70°, Ks≤1; and when 40 m fill height with α >50°, Ks≤1. (5) The Ks recommended by the latest Chinese culvert design code differs to some extent from those by centrifugal model test and numerical simulation. In the case of α =45° with a small B value, the earth pressure concentration coefficient Ks at the top of a culvert of the code is more conservative. (6) Ks of high-fill arch culvert in valley is related to the formation of arch top compaction area and isobaric surface. The arch top compaction area can cause the earth pressure concentration on the top of the arch culvert, and cause the vertical earth pressure of the soil around the compaction area to be arched. At a certain depth approaching the surface of the fill, the arch distribution gradually transits to the horizontal distribution, thus forming an isobaric surface. The upper load of the isobaric surface will be dispersed on the valley slope, so the unloading effect of the valley topography can be exerted.

The process of chemical exchange saturation transfer (CEST) is quantified by evaluating a Z-spectra, where CEST signal quantification and Z-spectra fitting have been widely used to distinguish the contributions from multiple origins. Based on the exchange-dependent relaxation rate in the rotating frame (Rex), this paper introduces an additional pathway to quantitative separation of CEST effect. The proposed Rex-line-fit method is solved by a multi-pool model and presents the advantage of only being dependent of the specific parameters (solute concentration, solute‐water exchange rate, solute transverse relaxation, and irradiation power). Herein we show that both solute‐water exchange rate and solute concentration monotonously vary with Rex for Amide, Guanidino, NOE and MT, which has the potential to assist in solving quantitative separation of CEST effect. Furthermore, we achieve Rex imaging of Amide, Guanidino, NOE and MT, which may provide direct insight into the dependency of measurable CEST effects on underlying parameters such as the exchange rate and solute concentration, as well as the solute transverse relaxation. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the differences in complications between hepatitis B virus (HBV)-related and alcohol-related cirrhoses.

IntroductionMidshaft clavicular fractures are common amongst young adults. Conservative or surgical treatment for definitive fracture management has been widely debate, both with their pros and cons. Previous meta-analyses compared the clinical outcomes between conservative and surgical treatment options of midshaft clavicular fractures but failed to elucidate any difference in functional improvement. We postulate that functional improvement after fracture union plateaus and the clinical outcome after treatment varies at different time points. This meta-analysis will focus on the synthesis comparison of outcomes at early, short-term results (3 months), intermediate-term (6 to 12 months) and long-term (>24 months) clinical outcomes.MethodsA systematic search was done on databases (Pubmed, Embase, Medline, Cochrane) in June 2021. Search keywords were: midshaft clavicular fractures and clinical trials. Clinical trials fulfilling the inclusion criteria were selected for comparison and the clinical outcomes of midshaft clavicular fractures using surgical and non-surgical interventions in terms of improvement in the Disabilities of the Arm, Shoulder and Hand (DASH) score, Constant-Murley Score (CMS), time to union and risk ratio of treatment related complications were analysed in correlation with post-treatment timeframe.ResultsOf the 3094 patients of mean age 36.7 years in the 31 selected studies, surgical intervention was associated with improved DASH score (standard-mean difference SMD -0.22, 95% CI -0.36 to -0.07, p = 0.003; mean difference MD -1.72, 95% CI -2.93 to -0.51, p = 0.005), CMS (SMD 0.44, 95% CI 0.17-0.72, p = 0.001; MD 3.64, 95% CI 1.09 to 6.19, p = 0.005), time to union (non-adjusted SMD -2.83, 95% CI -4.59 to -1.07, p = 0.002; adjusted SMD -0.69, 95% CI -0.97 to -0.41, p24 months SMD -4.24, 95% CI -7.03 to -1.45, p = 0.003) and CMS (>24 months, SMD 1.03, 95% CI 0.39 to 1.68, p = 0.002; MD 5.77, 95% CI 1.63 to 9.91, p = 0.006). Surgical outcome is independent of fixation with plates or intra-medullary nails.ConclusionSurgical intervention was associated with better clinical outcomes compared with non-surgical approach for midshaft clavicular fractures in terms of improvement in functional scores DASH, CMS, time to union and fracture related complications, although not to the minimal clinically significant difference. Benefits in the long-term functional improvements are more pronounced.