RESUMO
The performance of an air purifier is determined by its clean air delivery rate (CADR), expressed as the product of the air flowrate and filter collection efficiency. A high CADR in a commercial air purifier is achieved using a pleated air filter with high filtration performance at a given air flowrate. However, obtaining this high filtration performance depends on the knowledge of the manufacturer, including the optimal pleating design, which remains uncertain to date. In this study, test pleated filters were prepared by folding a flat electrostatically-charged E12 filter medium to obtain different pleating geometries. The proper pleat geometry of the pleated filter, which has a minimum pressure drop at a fixed air flowrate, was dependent on the pleat length (PL ) and pleating ratio (α = pleat height/pleat width), wherein as the PL increases, the α range required to achieve a minimum pressure drop similarly increases. Based on the filter quality factor (qF ), the optimal pleat geometry of a pleated filter was between α values of 6-8, irrespective of the PL . Although both PL and α have certain influences on the qF , α has a greater influence on the pleated filter with no dead zone.
Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados , FiltraçãoRESUMO
Hospitals need to find a safe and rapid method for respiratory specimen collection as the number of patients suspicious for coronavirus disease -2019 (COVID-19) rapidly grows. Applied with significant infection control and prevention measures, a respiratory specimen collection booth was newly designed. The new respiratory specimen collection booth not only increased COVID-19 testing cases but also decreased personal protective equipment consumption.
Assuntos
Teste para COVID-19/instrumentação , Teste para COVID-19/métodos , COVID-19/diagnóstico , Controle de Infecções/métodos , Manejo de Espécimes/instrumentação , COVID-19/epidemiologia , Desinfecção/métodos , Desenho de Equipamento , Hospitais , Humanos , Equipamento de Proteção Individual , Manejo de Espécimes/métodosRESUMO
Polycaprolactone (PCL) was reported a long time ago; however, its biomedical applications has not been extensively investigated in comparison with poly(lactide- co-glycolide) (PLGA) due to its too slow degradation profile. Here, we are reporting an oxalate-connected oligocaprolactone multiblock copolymer (PCL-OX) as a fast degradable PCL while maintaining its crystalline properties and low melting point of PCL. The in vivo application of the paclitaxel-loaded PCL-OX microspheres provided a steady plasma drug concentration of 6-9 µg/mL over 28 days, similar to that of the PLGA microspheres. Both PCL and PLGA microspheres were completely cleared two months after in vivo implantation. The PCL-OX microspheres showed a similar tissue compatibility to that of PLGA microspheres in the subcutaneous layer of rats. These findings suggest that PCL-OX is a useful biomaterial that solves the slow degradation problems of PCL and, thus, may find uses in other biomedical applications as an alternative to PLGA.
Assuntos
Plásticos Biodegradáveis , Sistemas de Liberação de Medicamentos , Microesferas , Paclitaxel , Poliésteres , Animais , Plásticos Biodegradáveis/síntese química , Plásticos Biodegradáveis/química , Plásticos Biodegradáveis/farmacocinética , Plásticos Biodegradáveis/farmacologia , Implantes de Medicamento , Masculino , Paclitaxel/química , Paclitaxel/farmacocinética , Paclitaxel/farmacologia , Poliésteres/química , Poliésteres/farmacocinética , Poliésteres/farmacologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/farmacocinética , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
Cadaveric shortages have been a challenge to anatomy education; as access remains low in many parts of the world, institutions are relying on plastinated specimens. Plastination typically requires the use of complex equipment and patented chemicals. While models solve cost and toxicity issues, in neuroanatomical education, the rigidity prevents deep-brain structure exploration and visual-spatial learning. The Elnady technique (ET) developed by Dr. Fawzy Elnady is an alternative method that solves the limitations of traditional plastination while maintaining the advantages previously developed in animal models. The superficial temporal artery (STA), brain stem, cerebellum, right hemisphere, and latex-injected cortex were previously embalmed, drained of their original solution, dehydrated in acetone baths, and hydrometer readings were taken. Specimens were placed in a glycerol bath, immersed in cornstarch and cured. Quantitative and qualitative data of weight (grams), size (millimeters), color, texture, and odor were obtained before and after processing the samples. Overall, specimens showed a change of 6.5% in weight, 8.5% in height, 4.8% in width, and 8.9% in length (millimeters) after the preservation process. The products had pliable texture, no change in color grossly and no detectable odor. The measurement of weight (grams) ranges from 0-15.7%, height from 0-12.3%, width from 0-11.1%, and length from 1.7-5.9%. The ET is an effective method for the preservation of human cadaveric specimens that produces quality samples from embalmed specimens. Preservation can be done without patented chemicals and special storage methods are usually required for plastination. It is an ideal technique for basic and/or low-resource settings and could resolve expenses related to acquiring and maintaining cadaveric brain specimens.
RESUMO
This study aimed to predict early breast cancer recurrence in women under 40 years of age using radiomics signature and clinicopathological information. We retrospectively investigated 155 patients under 40 years of age with invasive breast cancer who underwent MRI and surgery. Through stratified random sampling, 111 patients were assigned as the training set, and 44 were assigned as the validation set. Recurrence-associated factors were investigated based on recurrence within 5 years during the total follow-up period. A Rad-score was generated through texture analysis (3D slicer, ver. 4.8.0) of breast MRI using the least absolute shrinkage and selection operator Cox regression model. The Rad-score showed a significant association with disease-free survival (DFS) in the training set (p = 0.003) and validation set (p = 0.020) in the Kaplan-Meier analysis. The nomogram was generated through Cox proportional hazards models, and its predictive ability was validated. The nomogram included the Rad-score and estrogen receptor negativity as predictive factors and showed fair DFS predictive ability in both the training and validation sets (C-index 0.63, 95% CI 0.45-0.79). In conclusion, the Rad-score can predict the disease recurrence of invasive breast cancer in women under 40 years of age, and the Rad-score-based nomogram showed reasonably high DFS predictive ability, especially within 2 years of surgery.
RESUMO
Thermogel is an aqueous polymer solution that undergoes sol-to-gel transition as the temperature increases. Cells, growth factors, and signaling molecules can be incorporated simultaneously during the sol-to-gel transition. The cytocompatible procedure makes the thermogel an excellent platform for 3D culture of stem cells. This review focuses on the crucial questions that need to be addressed to achieve effective differentiation of stem cells into target cells, comprising low modulus, cell adhesion, and controlled supply of the growth factors. Recent progress in the use of thermogel as a 3D culture system of stem cells is summarized, and our perspectives on designing a new thermogel for 3D culture and its eventual application to injectable tissue engineering of stem cells are presented.
Assuntos
Polímeros/química , Células-Tronco/citologia , Engenharia Tecidual/métodos , Adesão Celular/fisiologia , Diferenciação Celular/fisiologia , TemperaturaRESUMO
Stem cell therapy for damaged cartilage suffers from low rates of retention, survival, and differentiation into chondrocytes at the target site. To solve these problems, here we propose a two-dimensional/three-dimensional (2D/3D) nanocomposite system. As a new two-dimensional (2D) material, hexagonal layered double hydroxides (LDHs) with a uniform lateral length of 2-3 µm were prepared by a hydrothermal process. Then, tonsil-derived mesenchymal stem cells (TMSCs), arginylglycylaspartic acid-coated LDHs, and kartogenin (KGN) were incorporated into the gel through the thermal-energy-driven gelation of the system. The cells exhibited a tendency to aggregate in the nanocomposite system. In particular, chondrogenic biomarkers of type II collagen and transcription factor SOX 9 significantly increased at both the mRNA and protein levels in the nanocomposite system, compared to the pure thermogel systems. The inorganic 2D materials increased the rigidity of the matrix, slowed down the release of a soluble factor (KGN), and improved cell-material interactions in the gel. The current 2D/3D nanocomposite system of bioactive LDH/thermogel can be a new platform material overcoming drawbacks of hydrogel-based 3D cell culture systems and is eventually expected to be applied as an injectable stem cell therapy.
Assuntos
Nanocompostos , Diferenciação Celular , Células Cultivadas , Condrócitos , Condrogênese , Hidróxidos , Células-Tronco Mesenquimais , Peptídeos , Células-Tronco , Engenharia TecidualRESUMO
Carbonization of zinc containing metal-organic frameworks produces porous carbon materials with an interesting linear relationship between the Zn/C ratio of the precursors and the surface area of the resulting carbon materials.