Endogenous automatic nerve discharge promotes nerve repair: an optimized animal model

Exogenous electrical nerve stimulation has been reported to promote nerve regeneration. Our previous study has suggested that endogenous automatic nerve discharge of the phrenic nerve and intercostal nerve has a positive effect on nerve regeneration at 1 month postoperatively, but a negative effect at 2 months postoperatively, which may be caused by scar compression. In this study, we designed four different rat models to avoid the negative effect from scar compression. The control group received musculocutaneous nerve cut and repair. The other three groups were subjected to side-to-side transfer of either the phrenic(phrenic nerve group), intercostal(intercostal nerve group) or thoracodorsal nerves(thoracic dorsal nerve group), with sural nerve autograft distal to the anastomosis site. Musculocutaneous nerve regeneration was assessed by electrophysiology of the musculocutaneous nerve, muscle tension, muscle wet weight, maximum cross-sectional area of biceps, and myelinated fiber numbers of the proximal and distal ends of the anastomosis site of the musculocutaneous nerve and the middle of the nerve graft. At 1 month postoperatively, compound muscle action potential amplitude of the biceps in the phrenic nerve group and the intercostal nerve group was statistically higher than that in the control group. The myelinated nerve fiber numbers in the distal end of the musculocutaneous nerve and nerve graft anastomosis in the phrenic nerve and the intercostal nerve groups were statistically higher than those in the control and thoracic dorsal nerve groups. The neural degeneration rate in the middle of the nerve graft in the thoracic dorsal nerve group was statistically higher than that in the phrenic nerve and the intercostal nerve groups. At 2 and 3 months postoperatively, no significant difference was detected between the groups in all the assessments. These findings confirm that the phrenic nerve and intercostal nerve have a positive effect on nerve regeneration at the early stage of recovery. This study established an optimized animal model in which suturing the nerve graft to the distal site of the musculocutaneous nerve anastomosis prevented the inhibition of recovery from scar compression.

Sox9 is indispensable for testis differentiation in the red-eared slider turtle,a reptile with temperaturedependent sex determination

SOX9(SRY-related HMG box gene 9)is an essential regulator of male sex determination and testis differentiation in many vertebrate species.However,the functional role of Sox9 in testis differentiation has not yet been identified in any reptilian species.Herein,Sox9 knockdown in the red-eared slider turtle(Trachemys scripta)embryos at a male-producing temperature led to complete male-to-female sex reversal,characterized by the formation of an ovary-like structure,disappearance of male marker AMH,and ectopic expression of ovarian regulator FOXL2,as well as a female distribution pattern of germ cells.Conversely,in-ovo overexpression of Sox9 at a female-producing temperature resulted in partial masculinization of putative female embryos,with the coexistence of AMH and FOXL2.Our study provides the first direct evidence that Sox9 is indispensable for testicular differentiation in a reptilian species,further confirming the conserved role of Sox9 in vertebrate sexual development.

A Hybrid Conjugate Gradient Algorithm for Nonconvex Functions and Its Applications in Image Restoration Problems

It is prominent that conjugate gradient method is a high-efficient solution way for large-scale optimization problems.However,most of the conjugate gradient methods do not have sufficient descent property.In this paper,without any line search,the presented method can generate sufficient descent directions and trust region property.While use some suitable conditions,the global convergence of the method is established with Armijo line search.Moreover,we study the proposed method for solving nonsmooth problems and establish its global convergence.The experiments show that the presented method can be applied to solve smooth and nonsmooth unconstrained problems,image restoration problems and Muskingum model successfully.

Identify Congested Links Based on Enlarged State Space

When paths share a common congested link, they will all suffer from a performance degradation. Boolean tomography exploits these performance-level correlations between different paths to identify the congested links. It is clear that the congestion of a path will be distinctly intensive when it traverses multiple congested links. We adopt an enlarged state space model to mirror different congestion levels and employ a system of integer equations, instead of Boolean equations, to describe relationships between the path states and the link states. We recast the problem of identifying congested links into a constraint optimization problem, including Boolean tomography as a special case. For a logical tree, we propose an up-to-bottom algorithm and prove that it always achieves a solution to the problem. Compared with existing algorithms, the simulation results show that our proposed algorithm achieves a higher detection rate while keeping a low false positive rate.

Effects of Mo promoters on the Cu-Fe bimetal catalysts for the DMC formation from CO_2 and methanol

The Mo-promoted Cu-Fe bimetal catalysts were prepared and used for the formation of dimethyl carbonate （DMC） from CO2 and methanol. The catalysts were characterized by X-ray diffraction （XRD）, temperature programmed reduction （TPR）, laser Raman spectra （LRS）, energy dispersive spectroscopy （EDS） and temperature programmed desorption （TPD） techniques. The experimental results demonstrated that the Mo promoters can decrease the reducibility and increase the dispersion of Cu-Fe clusters, The concentration balance of base-acid sites can be readily adjusted by changing the Mo content. The moderate concentration balance of acid and base sites was in favor of the DMC formation, Under optimal experimental conditions, the highest methanol conversion of 6,99% with a DMC selectivity of 87.7% can be obtained when 2.5 wt% of Mo was loaded.