Polyurethanes are popularly used in cardiovascular and other biomedical fields due to their good biocompatibility as well as mechanical properties. But they are subject to biodegradation in vivo for a long time, and cause inflammation, so improving the biocompatibility of medical polyurethanes is an important subject of biomaterials. Recent researches have focused on biological modelling of biomaterials for improving the biocompatibility of polyurethanes. This paper reviews two main methods for improving biocompatibility of polyurethanes-endothelial cells seeding and mimic biomembrane (phospholipid surface), and summarizes the main procedures and questions of these two methods.
Biocompatible Materials ; chemistry ; Endothelial Cells ; drug effects ; Humans ; Phospholipids ; chemistry ; Polyurethanes ; chemistry

The one-step method was adopted in this study to synthesize aliphatic polyurethane with 4,4-methylene dicyclohexyl diisocyanate(HMDI), 1,4-butanediol (BDO) and poly (tetrahydrofuran) (PTMG). The tests conducted on this material were: FIR spectrum, mechanical properties test, water contact angles test, hemolysis test and platelet adhesion test. Results showed that this material has a good tensile strength up to 30 Mpa, similar to aromaphatic polyurethane. But its tensile elongation, tensile permanent change, hydrophility are better than those of aromaphatic polyurethane. The hemolysis test and platelet adhesion test showed that it has good blood compatibility.
Animals ; Biocompatible Materials ; chemical synthesis ; chemistry ; toxicity ; In Vitro Techniques ; Materials Testing ; Platelet Adhesiveness ; drug effects ; Polyurethanes ; chemical synthesis ; chemistry ; toxicity ; Rabbits ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; Tensile Strength

Objective To explore the implementation effect of nurses′ hierarchical training plan based on training outline and nurses′ needs. Methods Nurses′ hierarchical training outline was established in accordance with three theoretical training modules(humanistic accomplishment, professional competence, career planning/development) as well as three skill training modules(basic nursing skills, specialist nursing skills and first aid nursing skills); the training needs of nurses were investigated by adopting a self-made Training Needs Questionnaire, then the hierarchical training plan was developed based on the training outline and nurses′ training needs. Results There were some differences in the training needs of different levels of nurses in the fields of clinical knowledge and skills,nursing management, nursing education, scientific research and new nursing guidelines and progress(F=2.80-22.47,P<0.05 or 0.01). Before the implementation of nurses′ hierarchical training plan based on training outline and nurses′ needs, nurses′ satisfaction about training, theoretical examination result, clinical working ability and patients′satisfaction towards nursing were 89.06%(228/256),94.80%(1 185/1 250), 96.63%(1 060/1 097) and 95.35%(5 470/5 737), respectively. Then, after the implementation, the corresponding values got improved into 96.76%(239/247), 97.44%(1 297/1 331), 98.75%(1 106/1 120) and 99.22%(6 070/6 118),which were statistically significant(χ2=11.11-176.27,P<0.01). Conclusion Integrating nurses′hierarchical training outline with the training needs helps to provide targeted hierarchical training so as to improve the professional quality of nurses and the patients′satisfaction towards nursing.

Automatic speaker gender identification based on voice feature is an important task in voice processing and analysis fields. In this paper non-linear parameters such as fractal dimension are applied to be one part of feature space for improving the ability of describing speaker gender feature through conventional linear parameters method. Pitch is picked using lifting scheme, and audio fractal dimension is extracted. Then based on Takens theory, the time delay method is used to reconstruct the phase space of fractal dimension sequence. And fractal dimension complexity is obtained by calculating Approximate Entropy. Three dimension feature vectors, including the pitch, the fractal dimension and the fractal dimension complexity, are applied to speaker gender identification. Experiment results show that through adding non-linear parameters, compared with the linear parameter using one dimension only such as pitch, the proposed method is more accurate and robust, and thus provides a new way for speaker gender identification.
Algorithms ; Artificial Intelligence ; Biometry ; methods ; Humans ; Nonlinear Dynamics ; Pattern Recognition, Automated ; methods ; Pitch Discrimination ; Sex Characteristics ; Signal Processing, Computer-Assisted ; Speech ; Speech Acoustics ; Voice

Adopting the two-step method and changing the proportion between PEG (Polyethylene glycol) and PTMG (poly (tetrahydrofuran), we used the MDI (4,4'-diphenylmethane diisocyanate) and short chain extender BDO (1,4-butanediol) as hard segment, the PTMG and PEG as soft segment, and hence prepared a series of polyether-based thermoplastic polyurethanes. FTIR showed the structure character of these polyurethanes. The determination of mechanics property and water contact angles revealed their good mechanics properties and hydrophilicity. Blood compatibility was evaluated by hemolysis test and platelet adhesion test, which revealed their good hemocompatibility. So those polyurethanes may be of wide application in the future.
Animals ; Biocompatible Materials ; chemical synthesis ; chemistry ; Butylene Glycols ; chemistry ; Isocyanates ; chemistry ; Materials Testing ; Polyethylene Glycols ; chemistry ; Polymers ; chemistry ; Polyurethanes ; chemical synthesis ; chemistry ; Rabbits

PEG (Mn = 1000)-segmented polyurethanes, with hard segment percentage of 40%, 50% and 55% and named PU-H40, PU-H50 and PU-H55 respectively, were synthesized by bulk polymerization. The structure of PU was characterized by FTIR, DSC, and GPC. Mechanical properties, water contact angles and water vapor transmit rate(WVTR) were also tested. FTIR and DSC showed that the degree of microphase separation increased with the hard content. Mechanical test showed the tensile strength of PU-H50 to be 25 MPa, the highest tensile strength of the PU series. By the use of PEG as soft segment, the surface hydrophilicity of the materials increased dramatically. Owing to its high degree of microphase separation and the mobility of soft segment, the water contact angle of PU-H55 attained to 33 degrees. The WVTRs of PU-H40, PU-H50 and PU-H55 were 789 g/m2/24h, 705 g/m2/24h and 623g/m2/24h respectively. These data suggest that the materials are suitable for fabricating such biomedical articles as surgical gloves, wound dressing and medical protective coating.
Biocompatible Materials ; chemical synthesis ; chemistry ; Humans ; Polyethylene Glycols ; chemistry ; Polyurethanes ; chemical synthesis ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Surface Properties

In this paper, a new calculating method of generalized dimension, based on boxes-coupling principle, is proposed to overcome the edge effects and to improve the capability of the speech endpoint detection which is based on the original calculating method of generalized dimension. This new method has been applied to speech endpoint detection. Firstly, the length of overlapping border was determined, and through calculating the generalized dimension by covering the speech signal with overlapped boxes, three-dimension feature vectors including the box dimension, the information dimension and the correlation dimension were obtained. Secondly, in the light of the relation between feature distance and similarity degree, feature extraction was conducted by use of common distance. Lastly, bi-threshold method was used to classify the speech signals. The results of experiment indicated that, by comparison with the original generalized dimension (OGD) and the spectral entropy (SE) algorithm, the proposed method is more robust and effective for detecting the speech signals which contain different kinds of noise in different signal noise ratio (SNR), especially in low SNR.
Artificial Intelligence ; Humans ; Pattern Recognition, Automated ; methods ; Signal Processing, Computer-Assisted ; Speech ; Speech Production Measurement ; methods ; Speech Recognition Software

In this article, the blood compatibility of polyurethanes (PUs) made by ourselves for catheters is studied by hemolysis test, platelets adhesion test, kinetic thrombus time test and dynamic clot formation. The results showed that these PUs all have excellent blood compatibility. Among these PUs, H50-100 and H60-100 have best blood compatibility. Additionally, the relationship between the structure and blood compatibility is discussed.
Animals ; Biocompatible Materials ; Blood ; Blood Coagulation Tests ; Catheterization ; instrumentation ; In Vitro Techniques ; Materials Testing ; Platelet Function Tests ; Polyurethanes ; Rabbits

Objective:To analyze and discuss the application value and teaching effect of simulate patients (SP)-assisted problem-based learning (PBL) combined with team-based learning (TBL) mode in pediatric first aid teaching, in order to provide a new reference for the reform of standardized residency training and teaching mode of pediatrics in the new era in China.Methods:A total of 103 residents who participated in the standardized training in the Department of Pediatrics of Hunan Children's Hospital from January 2018 to December 2020 were selected as the research objects, and they were divided into the control group (50 cases) and the experimental group (53 cases). The control group adopted the previous teaching mode of residents, while the experimental group adopted the SP-assisted PBL combined with TBL mode. In this study, SPSS 22.0 software was used for t test and chi-square test. Results:The examination scores of the experimental group in the theoretical knowledge of pediatric first aid, clinical thinking and skills, and application of pediatric first aid skills were higher than those in the control group [(86.98±3.42), (85.69±5.13), (89.62±4.75)] vs. [(77.23±4.16), (81.16±3.96), (76.54±5.78)], with statistically significant differences between the two groups ( P<0.05). The questionnaire survey showed that the clinical thinking and pediatric emergency skills, doctor-patient communication ability, teamwork ability and other aspects of the experimental group were significantly better than those of the control group ( P<0.05). Conclusion:The SP-assisted PBL combined with TBL mode can produce positive effects in the standardized residency training of pediatrics, which will help residents better master pediatric first aid skills, improve their clinical comprehensive capabilities, and be more conducive to improving the quality of pediatric residency training, which is worth promoting in the new era.