Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst

A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity evaluation.The results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst.

DCD角膜移植术后角膜内皮细胞与排斥反应的相关性分析

目的:探讨心脏死亡供体器官捐献(donation after cardiac death,DCD)来源角膜植片术后排斥反应与角膜内皮细胞的相关性。方法:用角膜内皮显微镜对心脏死亡供体来源角膜植片行穿透性角膜移植术后发生排斥反应的28例28眼角膜植片分别于术后<1、2~3、4~6、7~12mo行角膜内皮镜检查。结果:28例患者术后<1、2~3、4~6、7~12mo的角膜内皮细胞变异系数分别为38.23%、49.56%、57.18%、65.04%;角膜内皮细胞密度分别为2071.15±311.47、1771.33±348.18、1626.59±353.92、1553.14±307.31个/mm2;角膜内皮细胞变异系数与排斥反应呈正相关关系(r=0.95,P<0.05);术后角膜内皮细胞密度与排斥反应呈负相关关系(r=-0.93,P<0.05)。结论:DCD穿透性角膜移植术后发生排斥反应时有角膜内皮细胞变异系数逐步增高,角膜内皮细胞密度逐步降低的趋势;角膜内皮细胞变异系数、角膜内皮细胞密度可作为早期检测术后排斥反应的指标。

Fibroblast growth factor-4 and hepatocyte growth factor induce differentiation of human umbilical cord blood-derived mesenchymal stem cells into hepatocytes

AIM： To investigate the differentiation of human umbilical cord blood （HUCB）-derived mesenchymal stem cells （MSCs） into hepatocytes by induction of fibroblast growth factor-4 （FGF-4） and hepatocyte growth factor （HGF）, and to find a new source of cell types for therapies of hepatic diseases. METHODS： MSCs were isolated by combining gradient density centrifugation with plastic adherence. When HUCB-derived MSCs reached 70% confluence, they were cultured in Iscove modified Dulbecco medium （IMDM） supplemented with 10 mL/L FBS, 20 ng/mL HGF and 10 ng/mL FGF-4. The medium was changed every 4 d and stored for albumin, alpha-fetoprotein （AFP） and urea assay. Expression of CK-18 was detected by immunocytochemistry. Glycogen storage in hepatocytes was determined by PAS staining. RESULTS： By combining gradient density centrifugation with plastic adherence, we could isolate MSCs from 25.6% of human umbilical cord blood. When MSCs were cultured with FGF-4 and HGF, approximately 63.6% of cells became small, round and epithelioid on d 28 by morphology. Compared with the control, the level of AFP increased significantly from d 12 to 18.20：1=1.16 μg/L （t = 2.884, P〈0.05） in MSCs cultured with FGF-4 and HGF, and was higher （54.28±3.11 μg/L） on d 28 （t = 13.493, P〈0.01）. Albumin increased significantly on d 16 （t = 6.68, P〈0.01） to 1.02±0.15 μg/mL, and to 3.63±0.30 μg/mL on d 28 （t = 11.748, P〈0.01）. Urea （4.72±1.03 μmol/L） was detected on d 20 （t = 4.272, P〈0.01）, and continued to increase to 10.28±1.06 μmol/L on d 28 （t = 9.276, P〈0.01）. Cells expressed CK-18 on d 16. Glycogen storage was observed on d 24. CONCLUSION： HUCB-derived MSCs can differentiate into hepatocytes by induction of F-GF-4 and HGF. HUCB derived MSCs are a new source of cell types for cell transplantation therapy of hepatic diseases.

Imaging in detecting sites of pulmonary fibrosis induced by paraquat

BACKGROUND： The most common cause of death from paraquat （PQ） poisoning is respiratoryfailure from pulmonary fi brosis, which develops through pathological overproduction of extracellularmatrix proteins such as collagens. In this study, a MicroCT system was used to observe dynamicchanges of pulmonary fi brosis in rats with PQ poisoning, and fi nd the characteristics of interstitial lungdiseases via density-based and texture-based analysis of CT images of the lung structure.METHODS： A total of 15 male SD rats were randomly divided into a control group （n=5） and aPQ poisoning group （n=10）. The rats in the poisoning group were intraperitoneally administered with4 mg/ mL PQ at 14 mg/kg, and the rats in the control group were administered with the same volumeof saline. The signs of pulmonary fi brosis observed by the MicroCT included ground-glass opacity,nodular pattern, subpleural interstitial thickening, consolidation honeycomb-like shadow of the lung.RESULTS： Compared with the control group, the rats with acute PQ poisoning had differentsigns of pulmonary fibrosis. Ground-glass opacity and consolidation of the lung appeared at theearly phase of pulmonary fi brosis, and subpleural interstitial thickening and honeycomb-like shadowdeveloped at the middle or later stage. MicroCT images showed that fibrotic lung tissues weredenser than normal lungs, and their density was up-regulated with pulmonary fi brosis. There was nodifference in the progress of pulmonary fi brosis between the right lung and the left lung （P〉0.05）, butthere were differences in fi brosis degree at different sites in the lung （P〈0.05 or P〈0.01）. Pulmonaryfi brosis was mainly seen in the exterior area of the middle-lower part of the lung.CONCLUSION： Imaging can show the development of pulmonary fi brosis in PQ poisoning rats,and this method may help to administer drugs more reasonably in treating pulmonary fi brosis.

Three novel missense germline mutations in different exons of MSH6 gene in Chinese hereditary non-polyposis colorectal cancer families

AIM: To investigate the germline mutations of MSH6 gene in probands of Chinese hereditary non-polyposis colorectal cancer (HNPCC) families fulfilling different clinical criteria. METHODS: Germline mutations of MSH6 gene were detected by PCR-based DNA sequencing in 39 unrelated HNPCC probands fulfilling different clinical criteria in which MSH2 and MLH1 mutations were excluded. To further investigate the pathological effects of detected missense mutations, we analyzed the above related MSH6 exons using PCR-based sequencing in 137 healthy persons with no family history. The clinicopathological features were collected from the Archive Library of Cancer Hospital, Fudan University and analyzed. RESULTS: Four germline missense mutations distributed in the 4th, 6th and 9th exons were observed. Of them, three were not found in international HNPCC databases and did not occur in 137 healthy controls, indicating that they were novel missense mutations. The remaining mutation which is consistent with the case H14 at c.3488A>T of exon 6 of MSH6 gene was also found in the controls, the rate was approximately 3.65% (5/137) and the type of mutation was not found in the international HNPCC mutational and SNP databases, suggesting that this missense mutation was a new SNP unreported up to date. CONCLUSION: Three novel missense mutations and a new SNP observed in the probands of Chinese HNPCC families, may play an important role in the development of HNPCC.

A method for calculating probability of collision between space objects

A method is developed to calculate probability of collision. Based on geometric features of space objects during the encounter, it is reasonable to separate the radial orbital motions from those in the cross section for most encounter events that occur in a near-circular orbit. Therefore, the probability of collision caused by differences in both altitude of the orbit in the radial direction and the probability of collision caused by differences in arrival time in the cross section are calculated. The net probability of collision is expressed as an explicit expression by multiplying the above two components. Numerical cases are applied to test this method by comparing the results with the general method. The results indicate that this method is valid for most encounter events that occur in near-circular orbits.

Successful recovery of COVID-19-associated recurrent diarrhea and gastrointestinal hemorrhage using convalescent plasma

Background: Gastrointestinal symptoms are not rare among coronavirus disease 2019(COVID-19) patients, but there have been no reports regarding convalescent plasma therapy for the recovery of gastrointestinal problems in COVID-19 patients.Case presentation: We present two cases of patients with COVID-19-associated recurrent diarrhea and positive fecal occult blood who successfully recovered after a one-time convalescent plasma administration.Conclusion: When COVID-19 patients develop recurrent or refractory gastrointestinal symptoms and fail to respond to the available treatment, alternative therapy with convalescent plasma administration may be considered.

Multicentric reticulohistiocytosis with prominent skin lesions and arthritis:A case report

BACKGROUND Multicentric reticulohistiocytosis(MRH)is a rare non-Langerhans histiocytosis of unknown etiology characterized by papulonodular skin lesions and progressive,erosive arthritis.To date,there have been approximately 300 cases of MRH reported worldwide.The majority of patients are Caucasian from western countries,and Asian patients are rare.Here,we report a case of MRH in a Chinese patient.CASE SUMMARY A 38-year-old male was admitted to the hospital with a rash that had persisted for over 2 years and bilateral knee pain for over 1 year.The patient’s symptoms had previously been misdiagnosed as eczema when there were only skin symptoms and was finally diagnosed as MRH after a skin biopsy of the left upper back.The patient was treated with glucocorticoids combined with an immunosuppressive regimen.While the skin lesions on both arms,abdomen,and back subsided,the skin lesions on the rest of the body did not increase.The interphalangeal joints of both thumbs and bilateral knee joints remained swollen and painful.CONCLUSION The case will help clinicians better identify and treat this disease in the absence of epidemiological studies or randomized controlled data.

Research and Development of Virtual Instruments System Based on Depth Camera

This paper takes advantage of the depth camera of somatosensory kinect and sensors to implement gesture recognition and design a virtual instrument system. As long as the user waves his arm without the help of other equipments, our system can automatically recognize the hand gesture and make suitable sound. In order to achieve depth camera's detection of hands movement,this paper introduce the depth imaging technology Light Coding and bone tracking technology to obtain the actual position information and hand movement information of the human body. Feet movement detection uses sensor technology, different stampede strength outputs different digital number after AD conversion so that the intensity can be controlled. A series of experiments show that the system has good fluency and practicality and increased the fun of playing instruments.

Micropillar-arrayed surfaces promote transforming growth factor beta 1 induced epithelial to mesenchymal transition by focal adhesion kinase-related signaling in A549 cells

To the Editor:Substrate rigidity and topography are two important biomechanical factors that can modulate the biological behavior of cancer cells such as epithelial to mesenchymal transition(EMT).Currently,although studies have begun to focus on how the mechanical microenvironment determines the fate of multiple cells,the mechanism of the mechanical microenvironment affecting EMT is still unclear.