Novel roughness-controlled mannitol/LB Agar microparticles were synthesized by polymorphic transformation and self-assembly method using hexane as the polymorphic transformation reagent and spray-dried mannitol/LB Agar microparticles as the starting material. As-prepared microparticles were characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction spectra (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and Andersen Cascade Impactor (ACI). The XRD and DSC results indicate that after immersing spray-dried mannitol/LB Agar microparticles in hexane, β-mannitol was completely transformed to α-mannitol in 1 h, and all the δ-mannitol was transformed to α form after 14 days. SEM shows that during the transformation the nanobelts on the spray-dried mannitol/LB Agar microparticles become more dispersed and the contour of the individual nanobelts becomes more noticeable. Afterward, the nanobelts self-assemble to nanorods and result in rod-covered mannitol/LB Agar microparticles. FTIR indicates new hydrogen bonds were formed among mannitol, LB Agar, and hexane. SEM images coupled with image analysis software reveal that different surface morphology of the microparticles have different drug adhesion mechanisms. Comparison of ACI results and image analysis of SEM images shows that an increase in the particle surface roughness can increase the fine particle fractions (FPFs) using the rod-covered mannitol microparticles as drug carriers. Transformed microparticles show higher FPFs than commercially available lactose carriers. An FPF of 28.6 ± 2.4% was achieved by microparticles transformed from spray-dried microparticles using 2% mannitol(w/v)/LB Agar as feed solution. It is comparable to the highest FPF reported in the literature using lactose and spray-dried mannitol as carriers.
Mục tiêu: Khảo sát thể tích tồn lưu dạ dày và mức độ hài lòng của người bệnh khi được uống 200ml dung dịch maltodextrin 12,5% trước gây mê phẫu thuật 2 giờ. Đối tượng và phương pháp: Nghiên cứu tiến cứu có so sánh được thực hiện trên 102 người bệnh phẫu thuật cố định cột sống tại Khoa Chấn thương Chỉnh hình Cột sống, Bệnh viện Trung ương Quân đội 108 từ tháng 09/2021 đến tháng 03/2022. Kết quả: Phân loại sức khỏe theo ASA chiếm đa số ở nhóm II 82,35%; nhóm III chiếm 7,84%. Lượng dịch thể tích tồn dư dạ dày ở nhóm can thiệp là 29,68 ± 14,89ml thấp hơn nhóm chứng là 32,45 ± 12,77ml sự khác biệt không có ý nghĩa thống kê với p>0,05. Mức độ khát ở nhóm can thiệp thấp hơn nhóm chứng trước phẫu thuật và sau phẫu thuật 2 giờ. Nhóm can thiệp uống dung dịch maltodextrin trước gây mê phẫu thuật có tỷ lệ hài lòng cao hơn gấp 2,86 lần nhóm không uống. Kết luận: Người bệnh uống 200ml dung dịch maltodextrin 12,5% trước gây mê 2 giờ giảm mức độ khát, đói cho bệnh nhân phẫu thuật cột sống. Có sự khác biệt về sự hài lòng của nhóm uống dung dịch maltodextrin trước phẫu thuật đối với nhóm chứng.
Determination of accurate paddy field surface profile has great importance to designing the paddy tractor suspension system. With this aim, a new test rig has been designed and developed to measure paddy field surface profiles using static level method (sampled interval of 200mm). The data were analyzed through Matlab/Simulink software to obtain power spectral densities (0.05-3.5c/m) of the measured profiles on a log-log scale and it was found that the amplitude variation of the power spectral density (PSD) at low spatial frequency was higher than at high spatial frequency whereas the undulation of the PSD curve was largely changed from low to high frequency with roughness coefficient of 645.06x10-6 m3/cycle and slope value of 1.2399 representing the paddy field surface roughness under class D of ISO 8608 standards. This classification has great significance in the field of tractor vibration simulation work. Keywords: Paddy field surface, Rod and Level, Static level method, ISO 8608.
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