Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve

Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhe-sion stage. Moreover, seeded cells were distributed throughout the material.

Effect of biofeedback combined with high-quality nursing in treatment of functional constipation

BACKGROUND Functional constipation(FC)is a common functional gastrointestinal disease with various clinical manifestations.It is a physical and mental disease,which seriously affects patient physical and mental health and quality of life.Biofeedback therapy is the treatment of choice for FC,especially outlet obstructive constipation caused by pelvic floor dysfunction.High-quality nursing is a new nursing model in modern clinical work and a new concept of modern nursing service.AIM To explore the effect of biofeedback combined with high-quality nursing in the treatment of FC.METHODS A total of 100 patients with FC admitted to our hospital from March 2015 to July 2019 were selected for clinical observation.These patients were randomly divided into two groups of 50:Experimental group(biofeedback combined with highquality nursing treatment group)and control group(biofeedback group).RESULTS The constipation symptom score of the experimental group was significantly lower than that of the control group,and the difference was statistically significant(P<0.05).The anal canal resting pressure and initial defecation threshold of the experimental group were significantly lower than those of the control group,and the maximum squeeze systolic pressure of the anal canal of the experimental group was significantly higher than that of the control group(P<0.05).The Self-Rating Anxiety Scale and Zung’s Self-Rating Depression Scale scores of the two groups were significantly lower than before treatment.The Self-Rating Anxiety Scale and Self-Rating Depression Scale scores of the experimental group were significantly lower than those of the control group(P<0.05).The patient satisfaction score of the experimental group was significantly higher than that of the control group(P<0.05).CONCLUSION The application of biofeedback combined with high-quality nursing in the treatment of FC has significant advantages over pure biofeedback treatment,and it is worthy of promotion in clinical work.

Application of topological soliton in modeling protein folding: Recent progress and perspective

Proteins are important biological molecules whose structures are closely related to their specific functions. Understanding how the protein folds under physical principles, known as the protein folding problem, is one of the main tasks in modern biophysics. Coarse-grained methods play an increasingly important role in the simulation of protein folding, especially for large proteins. In recent years, we proposed a novel coarse-grained method derived from the topological soliton model, in terms of the backbone Cα chain. In this review, we will first systematically address the theoretical method of topological soliton. Then some successful applications will be displayed, including the thermodynamics simulation of protein folding, the property analysis of dynamic conformations, and the multi-scale simulation scheme. Finally, we will give a perspective on the development and application of topological soliton.

Grey incidence clustering method based on multidimensional dynamic time warping distance

The traditional grey incidence degree is mainly based on the distance analysis methods, which is measured by the displacement difference between corresponding points between sequences. When some data of sequences are missing (inconsistency in the length of the sequences), the only way is to delete the longer sequences or to fill the shorter sequences. Therefore, some uncertainty is introduced. To solve this problem, by introducing three-dimensional grey incidence degree (3D-GID), a novel GID based on the multidimensional dynamic time warping distance (MDDTW distance-GID) is proposed. On the basis of it, the corresponding grey incidence clustering (MDDTW distance-GIC) method is constructed. It not only has the simpler computation process, but also can be applied to the incidence comparison between uncertain multidimensional sequences directly. The experiment shows that MDDTW distance-GIC is more accurate when dealing with the uncertain sequences. Compared with the traditional GIC method, the precision of the MDDTW distance-GIC method has increased nearly 30%.

Effect of Morphine combined with Dezocine on analgesic effect and serum Glu and Cor levels in elderly patients with AD after hip replacement

Objective:To observe the analgesic effect of morphine combined with dezocine on elderly patients with AD after hip replacement and the effects of serum Glu and Cor levels.Methods:Totally 120 patients who underwent THR in our hospital from February 2016 to September 2017 were selected as study subjects.They were randomly divided into control group(n=60)and observation group(n=60).The control group was given hydromorphone hydrochloride analgesia after operation,while the observation group was given hydromorphone hydrochloride combined with dezocine for analgesia.The VAS score and Ramsay score of the two groups were observed.The addition of analgesics after operation was compared between the two groups.The levels of inflammatory factors and serum Glu and Cor were measured.The adverse reactions of the two groups were observed.Result:At 48 hours after operation,the VAS score of the observation group was lower than that of the control group(P<0.05).There was no significant difference in Ramsay score between the two groups at 1 hour after operation and 48 hours after operation(P>0.05).In the observation group,the additional use rate of analgesics was 8.33%,which was significantly lower than that of the control group(23.33%,P<0.05),and the dosage of analgesics was significantly lower than that of the control group(P<0.05);24 hours after operation,the levels of CRP,IL-6 and TNF-alpha in the observation group were lower than those in the control group(P<0.05);there was no significant difference in the levels of Cor and Glu in the two groups immediately after operation(P>0.05).The serum Cor and Glu levels in the observation group were significantly lower than those in the control group at 8 hours and 12 hours after operation(P<0.05),and the incidence of adverse reactions in the observation group was 10%,significantly lower than that in the control group(31.67%,P<0.05).Conclusion:Morphine combined with Dezocine can effectively relieve postoperative pain,alleviate inflammation,reduce serum Cor and Glu levels,and reduce the incidence of adverse reactions in elderly patients with AD after hip replacement.It has certain clinical value.

Open reduction and Herbert screw fixation of Pipkin type IV femoral head fracture in an adolescent:A case report

BACKGROUND Femoral head fracture is extremely rare in children.This may be the youngest patient with femoral head fracture ever reported in the literature.There are few pediatric studies that focus on cases treated with open reduction via the modified Hardinge approach.CASE SUMMARY A 14-year-old female adolescent suffered a serious traffic accident when she was sitting on the back seat of a motorcycle.A pelvic radiograph and computed tomography revealed a proximal femoral fracture and slight acetabular rim fracture.This was diagnosed as a Pipkin type IV femoral head fracture.An open reduction and Herbert screw fixation was performed via a modified Hardinge approach.After 1-year follow-up,the patient could walk without aid and participate in physical activities.The X-ray results showed that the fractures healed well with no evidence of complications.CONCLUSION Open reduction and Herbert screw fixation is an available therapy to treat Pipkin type IV femoral head fractures in children.

Radio-frequency system of the high energy photon source

Purpose High energy photon source is a 6 GeV diffraction-limited storage ring light source currently under construction in Beijing.A low-frequency fundamental radio-frequency(rf)system of 166.6 MHz was proposed to accommodate the accelerator physics design.Superconducting rf(srf)technologies were chosen for the storage ring rf accompanied by solid-state power amplifiers and digital low-level rf controls.The design of the rf system was completed,and the parameters are frozen.Elucidation of the rf design with key parameters is desired.Methods The requirements from the accelerator physics design will be presented followed by the detailed rf design.The logic behind the choice of key rf parameters is elaborated.The configuration of the entire rf system is presented.Results and conclusions The fundamental srf cavity of 166.6 MHz was designed to accelerate the ultrarelativistic electron beam.Heavy damping of higher-order modes in these cavities is required to avoid the coupled bunch instabilities.An active third harmonic srf of 499.8 MHz was adopted to realize the required rf gymnastics.Normal-conducting 5-cell cavities will be used for the booster rf.Solid-state amplifiers of 2.4 MW in total will be installed at HEPS to drive these cavities in the booster and the storage ring.A digital low-level rf system will be used to regulate rf field inside each cavity with high stabilities.The rf configuration during the commissioning and the operation scenarios are also presented.

Evaluation of recombinant endostatin in the treatment of atherosclerotic plaques and neovascularization in rabbits

Objective： Atherosclerotic plaques and neovascularization play an important role in the course of coronary atherosclerosis. This study evaluated the effect of recombinant endostatin on experimental atherosclerotic plaques and neovasculanzation in rabbits. Methods： Eighteen healthy male rabbits were divided into three groups： control group, atherosclerotic model group, and recombinant endostatin treated group. The atherosclerotic model was es- tablished via a high-cholesterol diet after balloon catheter injury. The subject weights, serum total cholesterol, creatine kinase-myocardial band fraction （CKMB）, and matrix metalloproteinase-2 （MMP-2） were measured. Six weeks after treatment, the aortic roots were taken for pathological assay. The thickness ratio of the intima to media was measured by hematoxylin and eosin （HE） staining, and the number of neovessels was measured by immunohistochemistry via monoclonal antibody CD31 staining. Results： The weight, plasma total cholesterol, and CKMB were not significantly different between the atherosclerotic model group and the recombinant endostatin treated group, but much higher than those of the control group （P〈0.05）. The thickness ratio of the intima to media in the recombinant endostatin treated group was distinctly less than that in the atherosclerotic model group （P〈0.05）. The number of neovessels decreased dramatically （P〈0.05） and the content of MMP-2 decreased slightly without statistical difference （P〉0.05） in the recombinant endostatin treated group, compared to the atherosclerotic model group. Conclusions： Recombinant en- dostatin is able to inhibit the growth of neovascularization in the atherosclerotic plaque and the development of plaque.

Recurrence of non-cardiogenic pulmonary edema and sustained hypotension shock in cystic pheochromocytoma

本文介绍一例以胸痛、呼吸困难为主要表现,反复发生非心源性肺水肿、持续性低血压和急性冠脉综合征的囊性嗜铬细胞瘤患者。囊性嗜铬细胞瘤合并多种严重并发症临床上少有报道,容易误诊和漏诊。对于出现肺水肿、持续性低血压和急性冠脉综合征等严重体征,临床诊断又不明确的患者,需要考虑嗜铬细胞瘤的可能。

Microphysical Properties of Convective Clouds in Summer over the Tibetan Plateau from SNPP/VIIRS Satellite Data

The Tibetan Plateau (TP) plays an important role in formation and development of the East Asian atmospheric circulation, climate variability, and disastrous weathers in China. Among the many topics on TP meteorology, it is critical to understand the microphysical characteristics of clouds over the TP;however, observations of the cloud microphysics in this area are insufficient mainly due to sparse stations and limited cloud physical data. The Visible Infrared Imaging Radiometer Suite (VⅡRS), onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite, has an improved imaging spectroradiometer with 17 channels of 750-m moderate resolution and 5 channels of 375-m image resolution. The high-resolution instrument has an advantage for observing the small or initial convective clouds. Based on the methodologies that we proposed before for retrieving cloud microphysical properties from SNPP, an automated mapping software package named Automatic Mapping of Convective Clouds (AMCC) has been developed at the scale of satellite swath. The properties of convective clouds are retrieved by AMCC and their values are averaged over 0.33°×0.33° grids based on the SNPP/VⅡRS satellite data over the TP during the summers of 2013-17. The results show that:(1) the temperature of lifting condensation level (TLCL) at Naqu meteorological station and the cloud base temperature (Tb) retrieved from VⅡRS are linearly correlated, with a correlation coefficient of 0.87 and standard deviation (STD) of 3.0℃;(2) convective clouds over the TP have the following macro-and microphysical properties. First, the cloud base temperature (Tb) is about -5℃, the cloud base height above the ground (Hb) ranges between 1800 and 2200 m, and the cloud water content is low. Second, the cloud condensation nuclei concentration (NCCN) is between 200 and 400 mg-1 with 0.7% in maximum supersaturation (Smax);consequently, the condensation growth of water cloud droplet with less NCCN and higher Smax is fast. Third, because the precipitation initiation depth (D14) varies within 1500-2000 m and 500-1000 m at the Yarlung Zangbo River basin and southern Tibet, respectively, the clouds over these areas are more prone to precipitation. Fourth, mean height of the cloud top above sea level (Htop) is between 10 and 13 km, but the cloud depth (Dcld) is rather small, which is about 5000 m in southern TP and gradually reduces to 2500 m in northern TP. Fifth, the glaciation temperature (Tg) ranges from -30℃ in central and southern TP to -25℃ in northern TP, which, combined with the warmer Tg and the Tb less than 0℃, leads to the domination of ice process in the clouds;(3) the macro-and microphysical properties of convective clouds over the TP explain why rainfall there is frequent and lasts over a short time with small amount and large rain drops.

g-C_(3)N_(4) encapsulated ZrO_(2) nanofibrous membrane decorated with CdS quantum dots: A hierarchically structured, self-supported electrocatalyst toward synergistic NH3 synthesis

The advancement of electrocatalytic N2 reduction reaction (NRR) toward ambient NH3 synthesis lies in the development of more affordable electrocatalysts than noble metals. Recently, various nanostructures of transition metal compounds have been proposed as effective electrocatalysts;however, they exist in the form of loose powders, which have to be immobilized on a matrix before serving as the electrode for electrolysis. The matrix, being it carbon paper, carbon cloth or metal foam, is electrocatalytically inactive, whose introduction inevitably raises the invalid weight while sacrificing the active sites of the electrode. Herein, we report on the fabrication of a flexible ZrO2 nanofibrous membrane as a novel, self-supported electrocatalyst. The heteroatom doping can not only endow the nanofibrous membrane with excellent flexibility, but also induce oxygen vacancies which are responsible for easier adsorption of N2 on the ZrO2 surface. To improve the electrocatalytic activity, a facile SILAR approach is employed to decorate it with CdS quantum dots (QDs), thereby tuning its Fermi level. To improve the conductivity, a g-C3N4 nanolayer is further deposited which is both conductive and active. The resulting hierarchically structured, self-supported electrocatalyst, consisting of g-C3N4 encapsulated ZrO2 nanofibrous membrane decorated with CdS QDs, integrates the merits of the three components, and exhibits a remarkable synergy toward NRR. Excellent NH3 yield of 6.32 × 10−10 mol·s−1cm−2 (−0.6 V vs. RHE) and Faradaic efficiency of 12.9% (−0.4 V vs. RHE) are attained in 0.1 M Na2SO4.

OFHC copper substrates for niobium sputtering:comparison of chemical etching recipes

Purpose Niobium sputtered on copper has been a popular alternative approach for superconducting radio frequency(SRF)community in the last few decades.Comparing to bulk materials of a few millimeters,high-purity niobium of merely a few microns is sufficient to realize superconductivity on the coated surface.Being niobium thin film,it has been widely acknowledged that surface quality of the substrate plays a vital role in obtaining a superior niobium coating with excellent SRF performance.Therefore,proper chemical treatment of the substrate before coating is crucial and the ultimate goal is to create a smooth and defect-free surface.Prior to the design of a cavity etching system,the mechanism of SUBU as well as two industry-used solutions is studied in detail on samples.Methods Copper samples were first pre-treated by mechanical grinding to remove fabrication damages,obvious defects and visible impurities.Two chemical solutions widely used in industries were subsequently chosen to etch the samples.Finally,the established SUBU solution was used independently on these pre-treated samples for comparison.Surface morphology and etching rate were measured accordingly.Results and conclusions Mirror-like copper surface was created by using the SUBU solution thus qualified for subsequent niobium sputtering,while the other two solutions used in industries were less effective with nonideal surface morphology.The chemical reactions,the experimental requisites and the involved processes are extensively elucidated for all three solutions.Limitations for SUBU were examined,and the optimum ratio of the chemical bath volume to sample surface area was also determined.These investigations will serve as an important guidance for the development of a chemical etching system for elliptical copper cavities.

Pt/TiO_(2–x) nanofibrous aerogel for effective nitrogen reduction: A simple strategy for simultaneous Pt formation and TiO_(2–x) vacancy engineering

Electrocatalysis plays an increasingly important role in converting atmospheric molecules(e.g.,N_(2),CO_(2) and H_(2)O)to value-added products(e.g.,NH_(3),C_(2)H_(4)and H_(2)).However,developing a simple strategy for preparing catalysts with high performance for the effective conversion of clean energy is still full of chal-lenges.Herein,we describe a straightforward,one-step reduction method to achieve the formation of Pt nanoparticles(NPs)and the vacancy engineering of TiO_(2-x)nanofibers(NFs)simultaneously,which can be accomplished in 5 min.Furthermore,a Pt/TiO_(2-x)nanofibrous aerogel(NA)with an ordered cellular archi-tecture is prepared through a directional freezing technology.The Pt/TiO_(2-x)NA with excellent mechanical properties can be made into a self-supporting electrode for electrocatalytic N_(2)reduction reaction(NRR),showing high NH_(3) yield rate(4.81×10^(-10)mol/s cm^(-2))and Faraday efficiency(14.9%)at-0.35 V vs.RHE.

A learning-based synthesis approach to decentralized supervisory control of discrete event systems with unknown plants

In this paper, we consider the problem of automatic synthesis of decentralized supervisor for uncertain discrete event systems. In particular, we study the case when the uncontrolled plant is unknown a priori. To deal with the unknown plants, we first characterize the conormality of prefix-closed regular languages and propose formulas for computing the supremal conormal sublanguages; then sufficient conditions for the existence of decentralized supervisors are given in terms of language controllability and conormality and a learning-based algorithm to synthesize the supervisor automatically is proposed. Moreover, the paper also studies the on-line decentralized supervisory control of concurrent discrete event systems that are composed of multiple interacting unknown modules. We use the concept of modular controllability to characterize the necessary and sufficient conditions for the existence of the local supervisors, which consist of a set of local supervisor modules, one for each plant module and which determines its control actions based on the locally observed behaviors, and an on-line learning-based local synthesis algorithm is also presented. The correctness and convergence of the proposed algorithms are proved, and their implementation are illustrated through examples.

Surface preparation by mechanical polishing of the 1.3-GHzmono-cell copper cavity substrate prior chemical etching for niobium coating

Purpose Surface quality of the substrate is widely acknowledged to be essential for the niobium thin film deposition. Mucheffort has thus been spent to improve the surface roughness by using various chemical etching techniques. However, surfacepreparation before the chemical etching also plays a part in obtaining a satisfactory substrate, but has rarely been studiedbefore. This paper aims to define a specification for the pre-polished copper substrate prior chemical etching and searches forsuitable alternative non-chemical grinding methods for the copper cavity.Methods Copper samples were mechanically pre-polished at first by using flap sanding wheels of different grits and thenchemically etched by using the well-established SUBU solutions. Surface roughness, as a figure of merit, was measuredand compared before and after SUBU. Optimum practice for pre-polishing may therefore be determined. The mechanicalgrinding was subsequently applied on the 1.3-GHz mono-cell copper cavity. Meantime, the previously reported centrifugalbarrel polishing method was also applied with new abrasive materials and modified schemes. A comprehensive study ofetching rate, surface roughness and morphologies was conducted.Results and conclusions The specification for surface roughness prior SUBU was determined. Due to a complex geometryand curved surfaces possessed by the 1.3-GHz copper cavity, the traditional mechanical grinding was proved to be not ideal.Satisfactory surface quality was obtained by using the alternative centrifugal barrel polishing on the cavity. The proposed newscheme and new abrasive materials were demonstrated to be effective, and a mirror-like surface was achieved on the coppercavity. The traditional mechanical grinding can therefore be replaced. This constitutes a dedicated study on pre-polishing ofthe 1.3-GHz copper cavity substrate prior chemical etching for niobium sputtering.