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Currently, the field of microgear manufacturing faces various processing challenges, particularly in terms of size reduction; these challenges increase the complexity and costs of manufacturing. In this study, a technique for microgear manufacturing is aimed at reducing subsequent processing steps and enhancing material utilization. This technique involves the use of trough dies with extrusion-cutting processing, which enables workpieces to undergo forming in a negative clearance state, thus reducing subsequent processing time for micro products. We conducted finite element simulations using microgear dies, measuring stress, velocity, and flow during the forming process of four types of dies-flat, internal-trough, external-trough, and double-trough dies. The results indicated that the buffering effect of the troughs reduced the rate of increase in the material's internal stress. In the cavity, the material experiences a significant increase in hydrostatic pressure, leading to the formation of a "hydrostatic pressure wall". This pressure barrier imposes substantial constraints on the flow of the material during dynamic processes, making it difficult for the material to move into the remaining areas. This effectively enhances the blockage of material flow, demonstrating the critical role of hydrostatic pressure in controlling material distribution and movement. In addition, combining the characteristics of both into a double-trough die enhances the overall stability of forming velocity, reduces forming load and energy consumption, and maximizes material utilization. Results further revealed that microgears manufactured using double-trough dies exhibited defect-free surfaces, with a dimensional error of less than 5 µm and tolerances ranging from IT5 to IT6. Overall, this study offers new insights into the traditional field of microgear manufacturing, highlighting potential solutions for the challenges encountered in current microstamping processes.
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BACKGROUND: Competency-based medical education (CBME) is an outcomes-oriented approach focused on developing competencies that translate into clinical practice. Entrustable professional activities (EPAs) bridge competency assessment and clinical performance by delineating essential day-to-day activities that can be entrusted to trainees. EPAs have been widely adopted internationally, but not yet implemented for medical radiation professionals in Taiwan. MATERIALS AND METHODS: A nationwide consensus process engaged 97 experts in radiation technology education representing diagnostic radiography, radiation therapy, and nuclear medicine. Preliminary EPAs were developed through the focus group discussion and the modified Delphi method. The validity of these EPAs was evaluated using the QUEPA and EQual tools. RESULTS: Through iterative consensus building, six core EPAs with 18 component observable practice activities (OPAs) in total were developed, encompassing routines specific to each radiation technology specialty. QUEPA and EQual questionnaire data verified these EPAs were valid, and of high quality for clinical teaching and evaluation. CONCLUSION: The consensus development of tailored EPAs enables rigorous competency assessment during medical radiation technology education in Taiwan. Further expansion of EPAs and training of clinical staff could potentially enhance care quality by producing competent professionals.
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Educação Médica , Internato e Residência , Humanos , Competência Clínica , Taiwan , Educação Baseada em Competências/métodos , Qualidade da Assistência à SaúdeRESUMO
BACKGROUND/AIM: Nosocomial infection is a substantial clinical, societal and economic burden, especially during the COVID-19 pandemic. Patients with cancer are required to change into patient gowns before receiving radiotherapy. To improve efficiency and infection control, we designed novel intelligent devices for both gown distribution and recycling. We conducted a pilot study to provide evidence for the device in healthcare quality improvement. MATERIALS AND METHODS: We designed and set up intelligent machines with an infrared sensor for patient gown distribution and recycling. The performance of these machines was assessed by questionnaire survey of patients' perceptions and handling by laundry personnel. RESULTS: We composed a questionnaire to measure patient/personnel satisfaction upon gown handling based on the existing data of our hospital. Two generations of patient gown distribution machines were introduced. One was the novel automated device for both gown distribution and recycling. The other one was the conventional wooden cabinets and/or hamper stands with foot pedals. Survey results showed that approximately 90% satisfaction was achieved with the automated machines. Overall satisfaction with the new soiled gown recycling machines was significantly higher than that with the conventional receptacles (p<0.01). CONCLUSION: The automated patient gown distribution machines safely and efficiently provide patients with suitable gowns. The automated patient gown recycling machine reduces contamination of the gown recycling area. Using these machines improves infection control in the hospital environment and effectively reduces the risk of nosocomial infection.
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COVID-19 , Infecção Hospitalar , Neoplasias , Humanos , COVID-19/epidemiologia , Pandemias , Projetos Piloto , Infecção Hospitalar/prevenção & controle , Neoplasias/radioterapiaRESUMO
Mongolia has been a pristine environment without much pollution. Our objective is to study a section of the Tuul River to evaluate the present condition of this pristine environment. Sediment metal (Al, Fe, Mn, Cu, Zn, Pb, Ni, Cd, Hg, and Cr) concentrations and Pb-210 were sampled and analyzed. Results showed that metal concentrations are much higher at areas near the capital city and municipal sewage outlet, with enrichment factor values up to 18 for Cu, and 26 for Cr. Higher copper concentrations were found at sites about ~ 50 km downstream from the source, an indication that pollutions are spreading further down the river. Vertical metal concentration profiles indicated that pollutions could be traced back to the 1960s. Inefficient sewage treatment plants and poorly managed power plant ash ponds were major sources of metals leaking into the Tuul River. Sewage wastewater is carrying metals through Tuul River to the lower river basin. Dusts from ash ponds are airborne and transport to greater area. These findings indicate that new and alternative measures have to be enforced to prevent further pollution entering the Tuul River drainage basin and airborne dust to other broader regions of the Asia and ocean.
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Sedimentos Geológicos/química , Radioisótopos de Chumbo/análise , Mercúrio/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , Ásia , Poluição Ambiental , Metais Pesados/química , Mongólia , Rios , Esgotos , Poluentes Químicos da Água/químicaRESUMO
This study compares the dose response of irradiated polymer gel with acrylic and styrofoam housing while applying multi-detector CT (MDCT) and cone-beam CT (CBCT). The dose response for MDCT and CBCT, while using an acrylic phantom is 1.34 and 0.67 DeltaHU Gy(-1), respectively, and becomes 1.54 and 0.84 DeltaHU Gy(-1) while using styrofoam, suggesting styrofoam is the better housing material. While the dose response of MDCT is better than that of CBCT, CBCT is yet a promising 3D dosimetry technique, given its potentially better spatial resolution and sensitive dose interpretation capability.
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Tomografia Computadorizada de Feixe Cônico/instrumentação , Radiometria/instrumentação , Ecrans Intensificadores para Raios X , Desenho de Equipamento , Análise de Falha de Equipamento , Géis/efeitos da radiação , Projetos Piloto , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: The classic Kaposi's sarcoma (KS) patients usually present with progressive skin lesions over the lower extremities, following an indolent course. Although radiotherapy is an effective treatment for KS, radiation over these lesions is not without difficulty. The intrinsic difficulty resides in how a homogenous radiation dose over superficial lesions involving large areas and irregular surface is properly delivered. Several bolus techniques have thus been invented. MATERIALS AND METHODS: The Aquaplast RT Thermoplastic is a new type of bolus material that can be easily molded and conformed to the curvature of skin, with the equivalence to soft tissue in radiation interaction. RESULTS: This material was applied as the bolus for the irradiation of a classic KS patient, whose disease involved multiple skin areas over the right heel and ankle. Large parallel-opposed irradiation fields delivered by 60Co were used. Computed tomography demonstrated a close conformity of the bolus built-up by Aquaplast RT Thermoplastic to the surface of the ankle and foot. A dosimetry measurement further confirmed an adequate and homogenous distribution of desired dose around the lesions of the lower extremity. After a total dose of 39 Gy, divided in 13 fractions, the lesions remitted completely. CONCLUSION: Our data suggest that the use of Aquaplast RT Thermoplastic as a bolus material is helpful in delivering adequate dose to skin lesions of the lower extremities.
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Sarcoma de Kaposi/radioterapia , Idoso , Tornozelo , Calcanhar , Humanos , Masculino , Plásticos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Pele/efeitos da radiação , Resultado do TratamentoRESUMO
BACKGROUND: Classic Kaposi's sarcoma (KS), a neoplastic disease of vascular endothelial cells of the skin, is relatively prevalent in Eastern Europe and the Mediterranean region and radiation is one of the standard therapies. The clinical presentation and treatment results of classic KS from other regions have rarely been reported. PATIENTS AND METHODS: Between 1994 and 2006, patients who had histologically confirmed KS and no immunodeficiency status due to human immunodeficiency virus infection or organ transplantation, and were treated with radiotherapy at Department of Oncology, National Taiwan University Hospital, Japan, were reviewed. RESULTS: A total of 17 classic KS patients, with a median age of 69 years, were studied over a period of 12 years. All classic KS lesions involved lower extremities. Radiotherapy was delivered with either a 60Co unit or a linear accelerator, with the most commonly prescribed treatment being 3 Gy per fraction to a total dose of 39 Gy. In addition, several techniques using bolus were adopted to improve the radiation distribution over the skin of lower extremities. All irradiated KS lesions responded, with a complete response rate of 76%. The overall survival and progression-free survival rates of the group at 5 years were 85% and 58%, respectively. CONCLUSION: Radiation therapy for classic KS patients in a non-prevalent area, such as Taiwan, is safe and effective.
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Sarcoma de Kaposi/radioterapia , Neoplasias Cutâneas/radioterapia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Sarcoma de Kaposi/epidemiologia , Neoplasias Cutâneas/epidemiologia , Taiwan/epidemiologiaRESUMO
A great deal of effort was enforced to reduce the pollution of the Keelung River in the past 20 years. A set of sediments covering most of the Keelung River drainage basin was analyzed for bulk sediment heavy metal concentrations, grain size content and Pb-210 dating in order to understand the spatial variations of sediment heavy metal contents as well as to evaluate the effectiveness of pollution control. The results showed that anthropogenic pollution and grain size are two of the most important factors in controlling spatial variations of metals in the Keelung River sediments. In addition, little reduction of sediment heavy metal concentrations was observed in the Keelung River drainage basin. Large spatial variations of metals and grain size were observed. High concentrations of zinc, copper, lead and cadmium were found in sediments near the main outlets of the adjacent Da-Wu-Lun Industrial Park and municipal waste drainage systems. Anthropogenic sources of heavy metal have altered the natural sediment heavy metal distributions. Positive linear relationships between aluminum, iron and fine-grained sediments showed that spatial grain size variations controlled the natural aluminum and iron concentrations in sediments. Zinc, copper, lead and cadmium contents were much higher than those measured 15 years ago. The unusually high concentrations of heavy metals, high enrichment factors and their rapid increases with time in Pb-210 dated core showed that the efforts in heavy metal reduction were futile. A proper regulation to prevent further heavy metals from entering into the river is urgently needed.