Desenvolvimento e ensaio de um secador convectivo para alimentos

Dissertação de Mestrado em Qualidade e Tecnologia AlimentarA presente dissertação versa sobre a concepção e exploração de um secador convectivo de produtos alimentares. Partindo-se do invólucro exterior (secador), neste foi instalado o equipamento para promover o aquecimento e escoamento do ar interior. Para monitorizar e controlar o processo de secagem, procedeu-se à instrumentação da instalação para monitorização/controlo e registo de cada uma das variáveis, nomeadamente: temperatura e humidade do ar, assim como a pesagem contínua dos produtos durante a secagem. Com o objectivo de explorar o comportamento do secador, realizaram-se ensaios preliminares, em que se comparou a eficiência de secagem obtida com o secador desenvolvido e uma estufa. Nos ensaios finais comparam-se os resultados para duas variedades de maçã, a 'Golden Delicious' e a 'Granny Smith', ambas secadas no secador desenvolvido. Para efeitos de comparação realizaram-se várias análises, que envolveram a determinação da humidade, acidez, sólidos solúveis totais, a cor e a textura das respectivas maçãs, em fresco e depois de secadas, num intervalo de temperaturas de 30ºC e 60ºC. Além disso estudou-se também a cinética de secagem em termos de modelos de camada fina, e também por meio da equação de difusão de Fick. Assim, avaliaram-se algumas propriedades de transferência de massa, como a humidade de difusividade efectiva e o coeficiente de transferência convectiva de massa. Os resultados mostram que para ambas as variedades de maçãs estudadas, a secagem reduz a acidez e o teor em açúcares. No que respeita à cor, esta foi significativamente afetada pela secagem, resultando em elevados valores da diferença de cor total, entre 19.43 e 25,04. Quanto à textura, verificou-se que com a secagem as maçãs tornam-se menos duras e menos coesas. No que respeitou à cinética de secagem, os dados cinéticos foram tratados e ajustados de acordo com diferentes modelos de camada fina que foram: 'Page', 'Henderson' e 'Pabis', 'Logarítmico' e 'Vega-Lemus'. Dos modelos testados foi possível verificar que o modelo 'Vega-Lumus' foi o pior para descrever a cinética de secagem,sendo o de 'Page' o que mostrou melhor adaptação/comportamento. Além disso, verificou-se que a difusidade de massa aumenta com a temperatura, seguindo a função do tipo 'Arrhenius' para as variedades 'Golden Delicious' e 'Granny Smith'.ABSTRACT: This dissertacion examines the design and operation of a food convective dryer. Starting from the outer casing (dryer), all the equipment has been installed to promote the heating and air flow inside. To monitor and control the drying process, all the instrumentation for monitoring/control and registration of each variable was installed, in particular, regardind the variables such as temperature and humidity, as well as the continous weighing of the product during drying. In order to explore the behaviour of the dryer, preliminary tests were carried out, which compared the efficiency obtained by drying in the developed drier and in an oven dryer. In the definitive tests, two varieties of apples, 'Golden Delicious' and 'Granny Smith', were both dried in the developed drier and the results were compared. For this several tests were carried out, which involved the determination of humidity, acidity, total soluble solids, colour and texture of the respective apples, either in fresh and after dried at temperatures in the range of 30ºC to 60ºC. In addittion it was also studied the drying kinetics in terms of thin layer models, and also by Fick's diffusion equation. Thus, some mass tranfer properties were evaluated, such as moisture effective diffusivity and the coefficient of convective mass transfer.The results show that both varieties of apple at study, drying reduces the acidity and sugar content. As regards colour, this was significantly affected by drying, resulting in high values of total colour difference between 19.43 and 25.04. As to texture, it was found that drying turned the apples softer and less cohesive. With respect to drying kinetics, the experimental data were adjusted according to different thin layer models: 'Page', 'Henderson' and 'Pabis', 'logarithmic' and 'Vega-Lemus'. From the models tested, it was able to verify that the model Vega-Lemus was the worst to describe the kinetics of drying and the 'Page' showed the best fit/performance. Furthermore, it was found that the mass diffusivity increases with temperature, following an 'Arrhenius' function for varieties 'Golden Delicious' and 'Granny Smith'

Early mobilisation in critically ill COVID-19 patients: a subanalysis of the ESICM-initiated UNITE-COVID observational study

Background Early mobilisation (EM) is an intervention that may improve the outcome of critically ill patients. There is limited data on EM in COVID-19 patients and its use during the first pandemic wave. Methods This is a pre-planned subanalysis of the ESICM UNITE-COVID, an international multicenter observational study involving critically ill COVID-19 patients in the ICU between February 15th and May 15th, 2020. We analysed variables associated with the initiation of EM (within 72 h of ICU admission) and explored the impact of EM on mortality, ICU and hospital length of stay, as well as discharge location. Statistical analyses were done using (generalised) linear mixed-effect models and ANOVAs. Results Mobilisation data from 4190 patients from 280 ICUs in 45 countries were analysed. 1114 (26.6%) of these patients received mobilisation within 72 h after ICU admission; 3076 (73.4%) did not. In our analysis of factors associated with EM, mechanical ventilation at admission (OR 0.29; 95% CI 0.25, 0.35; p = 0.001), higher age (OR 0.99; 95% CI 0.98, 1.00; p ≤ 0.001), pre-existing asthma (OR 0.84; 95% CI 0.73, 0.98; p = 0.028), and pre-existing kidney disease (OR 0.84; 95% CI 0.71, 0.99; p = 0.036) were negatively associated with the initiation of EM. EM was associated with a higher chance of being discharged home (OR 1.31; 95% CI 1.08, 1.58; p = 0.007) but was not associated with length of stay in ICU (adj. difference 0.91 days; 95% CI − 0.47, 1.37, p = 0.34) and hospital (adj. difference 1.4 days; 95% CI − 0.62, 2.35, p = 0.24) or mortality (OR 0.88; 95% CI 0.7, 1.09, p = 0.24) when adjusted for covariates. Conclusions Our findings demonstrate that a quarter of COVID-19 patients received EM. There was no association found between EM in COVID-19 patients' ICU and hospital length of stay or mortality. However, EM in COVID-19 patients was associated with increased odds of being discharged home rather than to a care facility. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021)

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Clinical and organizational factors associated with mortality during the peak of first COVID-19 wave : the global UNITE-COVID study

Purpose To accommodate the unprecedented number of critically ill patients with pneumonia caused by coronavirus disease 2019 (COVID-19) expansion of the capacity of intensive care unit (ICU) to clinical areas not previously used for critical care was necessary. We describe the global burden of COVID-19 admissions and the clinical and organizational characteristics associated with outcomes in critically ill COVID-19 patients. Methods Multicenter, international, point prevalence study, including adult patients with SARS-CoV-2 infection confirmed by polymerase chain reaction (PCR) and a diagnosis of COVID-19 admitted to ICU between February 15th and May 15th, 2020. Results 4994 patients from 280 ICUs in 46 countries were included. Included ICUs increased their total capacity from 4931 to 7630 beds, deploying personnel from other areas. Overall, 1986 (39.8%) patients were admitted to surge capacity beds. Invasive ventilation at admission was present in 2325 (46.5%) patients and was required during ICU stay in 85.8% of patients. 60-day mortality was 33.9% (IQR across units: 20%-50%) and ICU mortality 32.7%. Older age, invasive mechanical ventilation, and acute kidney injury (AKI) were associated with increased mortality. These associations were also confirmed specifically in mechanically ventilated patients. Admission to surge capacity beds was not associated with mortality, even after controlling for other factors. Conclusions ICUs responded to the increase in COVID-19 patients by increasing bed availability and staff, admitting up to 40% of patients in surge capacity beds. Although mortality in this population was high, admission to a surge capacity bed was not associated with increased mortality. Older age, invasive mechanical ventilation, and AKI were identified as the strongest predictors of mortality

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)

Delayed colorectal cancer care during covid-19 pandemic (decor-19). Global perspective from an international survey

Background The widespread nature of coronavirus disease 2019 (COVID-19) has been unprecedented. We sought to analyze its global impact with a survey on colorectal cancer (CRC) care during the pandemic. Methods The impact of COVID-19 on preoperative assessment, elective surgery, and postoperative management of CRC patients was explored by a 35-item survey, which was distributed worldwide to members of surgical societies with an interest in CRC care. Respondents were divided into two comparator groups: 1) ‘delay’ group: CRC care affected by the pandemic; 2) ‘no delay’ group: unaltered CRC practice. Results A total of 1,051 respondents from 84 countries completed the survey. No substantial differences in demographics were found between the ‘delay’ (745, 70.9%) and ‘no delay’ (306, 29.1%) groups. Suspension of multidisciplinary team meetings, staff members quarantined or relocated to COVID-19 units, units fully dedicated to COVID-19 care, personal protective equipment not readily available were factors significantly associated to delays in endoscopy, radiology, surgery, histopathology and prolonged chemoradiation therapy-to-surgery intervals. In the ‘delay’ group, 48.9% of respondents reported a change in the initial surgical plan and 26.3% reported a shift from elective to urgent operations. Recovery of CRC care was associated with the status of the outbreak. Practicing in COVID-free units, no change in operative slots and staff members not relocated to COVID-19 units were statistically associated with unaltered CRC care in the ‘no delay’ group, while the geographical distribution was not. Conclusions Global changes in diagnostic and therapeutic CRC practices were evident. Changes were associated with differences in health-care delivery systems, hospital’s preparedness, resources availability, and local COVID-19 prevalence rather than geographical factors. Strategic planning is required to optimize CRC care