Surface Characterization and Platelet Adhesion on Thin Hydrogel Films of Poly(vinyl ether)

Poly­(vinyl ether), with short oxyethylene side chains which possess a simple and relatively polar structure, should be a unique candidate for a bioinert material thanks to its solubility in water. On the basis of living cationic copolymerization and subsequent ultraviolet light irradiation, thin films of poly­(2-methoxyethyl vinyl ether) with different cross-linking densities were prepared on solid substrates. The films were thickened in water, and the extent was dependent on the cross-linking density. Although the surface chemistry and aggregation states were almost identical to one another, the stiffness, or the softness, of the outermost region in the film was strongly dependent on the cross-linking density. That is, the interface between polymer and water became thicker, or more diffused, with decreasing cross-linking density. The blood compatibility based on the platelet adhesion on to the hydrogel films was better for a more diffused interface

Effect of Local Chain Dynamics on a Bioinert Interface

Although many kinds of synthetic polymers have been investigated to construct blood-compatible materials, only a few have achieved success. To establish molecular designs for blood-compatible polymers, the chain structure and dynamics at the water interface must be understood using solid evidence as the first bench mark. Here we show that polymer dynamics at the water interface impacts on structure of the interfacial water, resulting in a change in protein adsorption and of platelet adhesion. As a particular material, a blend composed of poly­(2-methoxyethyl acrylate) (PMEA) and poly­(methyl methacrylate) was used. PMEA was segregated to the water interface. While the local conformation of PMEA at the water interface was insensitive to its molecular weight, the local dynamics became faster with decreasing molecular weight, resulting in a disturbance of the network structure of waters at the interface. This leads to the extreme suppression of protein adsorption and platelet adhesion

Table_1_Ranking important predictors of the need for a high-acuity psychiatry unit among 2,064 inpatients admitted to psychiatric emergency hospitals: a random forest model.docx

AimsIn order to uphold and enhance the emergency psychiatric care system, a thorough comprehension of the characteristics of patients who require a high-acuity psychiatry unit is indispensable. We aimed to clarify the most important predictors of the need for a high-acuity psychiatry unit using a random forest model.MethodsThis cross-sectional study encompassed patients admitted to psychiatric emergency hospitals at 161 medical institutions across Japan between December 8, 2022, and January 31, 2023. Questionnaires were completed by psychiatrists, with a maximum of 30 patients assessed per medical institution. The questionnaires included psychiatrists’ assessment of the patient’s condition (exposure variables) and the need for a high-acuity psychiatry unit (outcome variables). The exposure variables consisted of 32 binary variables, including age, diagnoses, and clinical condition (i.e., factors on the clinical profile, emergency treatment requirements, and purpose of hospitalization). The outcome variable was the need for a high-acuity psychiatry unit, scored from 0 to 10. To identify the most important predictors of the need for a high-acuity psychiatry unit, we used a random forest model. As a sensitivity analysis, multivariate linear regression analysis was performed.ResultsData on 2,164 patients from 81 medical institutions were obtained (response rate, 50.3%). After excluding participants with missing values, this analysis included 2,064 patients. Of the 32 items, the top-5 predictors of the need for a high-acuity psychiatry unit were the essentiality of inpatient treatment (otherwise, symptoms will worsen or linger), need for 24-hour professional care, symptom severity, safety ensured by specialized equipment, and medication management. These items were each significantly and positively associated with the need for a high-acuity psychiatry unit in linear regression analyses (p ConclusionItems related to the patient’s clinical profile might hold greater importance in predicting the need for a high-acuity psychiatry unit than do items associated with age and diagnosis.</p