High-frequency photothermal processing of commercial polymers under femtosecond laser irradiation for waveguide writing

The processing of three commonly used commercial polymer films (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) with different thermal properties under femtosecond (450 fs) irradiations at high frequency (1 kHz-1 MHz) multi-pulse (N=10-18000) laser at λ=515 (1.34 J/cm2, radius 9 μm) is analysed in order to have knowledge of which material and laser conditions are more suitable to write waveguides. Thermal and ablative effects are observed after laser irradiations. Heat accumulation effects of successive pulses impinging are simulated through a photothermal model in order to explain the results of irradiating these materials. Thermal analyses (Modulated Differential Scanning Calorimetry (MDSC) and Thermogravimetry (TG)) are performed and used to explain the different behaviour of each polymer. Three different regimes (non-thermal, thermal and saturation) are identified and explained from the model and experimental results. A connection between ablation depth and simulated reached temperature is established. A study of which number of pulses/spot area and frequency are appropriate for a better shape and ablation depth for writing waveguides on these polymers is performed.The work was supported by “Generalitat Valenciana” (IDIFEDER/2021/014 cofunded by FEDER program, project PROMETEO/2021/006, and INVEST/2022/419 financed by Next Generation EU), “Ministerio de Ciencia e Innovación” of Spain (projects PID2021-123124OB-I00; PID2019-106601RB-I00) and UATALENTO18-10 by “Universidad de Alicante”

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Complicaciones en rinoplastia servicio de cirugía plástica Centro Médico Naval 2016-2017

Objetivo general: Identificar las complicaciones por rinoplastia en el Servicio de Cirugía plástica del Hospital Naval, en el período 2016-2017. La rinoplastia es uno de los procedimientos quirúrgicos más comunes, realizados por cirujanos plásticos, otorrinolaringólogos y cirujanos de cabeza y cuello. Puede tener como objetivo la búsqueda de una mejora estética, funcional o una combinación de ambas. No existe una técnica estandarizada, aplicable a todo paciente que será sometido a dicho procedimiento, pues cada caso debe de ser evaluado en relación a las consideraciones anatómicas de cada individuo. Las complicaciones del procedimiento pueden ser divididas en tempranas y tardías. Entre las primeras se incluyen: hemorragias, hematomas, infecciones, periostitis, edema, equimosis, problemas de piel y perforaciones septales. Muchas de ellas pueden ser evitadas teniendo un cuidado meticuloso durante el procedimiento y con una revisión minuciosa previa a la sutura de las heridas. Las tardías, por lo general, incluyen anormalidades de la punta nasal, tejido óseo y/o cartilaginoso, usualmente relacionadas a hipercorrección o falta de la misma. A pesar de ser esta cirugía una de las más frecuentemente realizadas en la especialidad de cirugía plástica, existe poca información con respecto de la incidencia de complicaciones a nivel nacional en nuestro país. Por este motivo, el estudio se centra en calcular dicha tasa y a la vez determinar las de aparición más frecuente. De esta manera, se podría tomar acción en la prevención de las mismas. Uno de los principales motivos por el cual se explica esta deficiencia en los registros, tanto en hospitales como en clínicas, es debido al ausentismo de los pacientes a sus controles posoperatorios, lo cual conlleva a un registro cronológico pobre de la aparición de las mismas.En el Hospital Naval se realiza una cantidad considerable de rinoplastias anualmente; sin embargo, existen deficiencias en el registro de las complicaciones que pueden llegar a ocurrir en el periodo posoperatorio. Es por este motivo que surge la idea de realizar un análisis estadístico de las mismas, con el fin de proporcionar datos acerca del tipo de complicación, la frecuencia y el momento del periodo posoperatorio en el cual se presentan. Actualmente no se dispone de un sistema estandarizado de clasificación de complicaciones que permita una aplicación fácil y práctica donde se precise el tiempo de aparición y localización anatómica de éstas, el cual permitiría anticipar su ocurrencia y planificar las medidas preventivas desde el periodo preoperatorio

High-frequency processing effects on three commercial polymers with different thermal properties under femtosecond laser irradiation

The response of three of the most used commercial polymers (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) with different thermal properties under irradiation with high frequency (1 kHz-1 MHz) femtosecond (450 fs) multi-pulse (N=10-1500) laser at λ=515 (1.34 J/cm2) and 1030 (1.70 J/cm2) is reported. Thermal and ablative effects are observed after laser irradiations. The results are compared to a photothermal model that pretends to explain the heat accumulation effect of successive pulses irradiation. Thermal analyses (Modulated Differential Scanning Calorimetry (MDSC) and Thermogravimetry (TG)) are performed and utilized to explain the different behaviour of each polymer. Three different regimes (non-thermal, thermal and saturation) are identified and explained from the model and experimental results. A connection between ablation depth and simulated reached temperature is established. Further studies as micro-Raman analyses on the irradiated area and the dependence of damaged area on the repetition rate are being performed

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study (vol 46, pg 2021, 2022)

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