Rheology of vitreous humour and pharmacological substitutes used in eye surgery

The Vitreous Humour (VH) is a transparent gel that fills the vitreous cavity in the Human eye. VH is mainly composed of water (99%) and includes a network of protein fibrils (collagen) and hyaluronan (1%). It is known that VH becomes progressively liquefied with age, or as a consequence of some diseases, and consequently the rheological, biomechanical and structural properties of the fluid also change. For the normal operation of the eye, when vitreoretinal pathologies appear, effective treatments must be performed. A common treatment for these diseases is the injection of a VH substitute in the vitreous cavity. The major vitreous substitutes commercially available are silicone oils and perfluorocarbon liquids, but currently there is little information about their rheological properties, which are known to be intimately linked to their functionality. The aim of this work is to measure the rheological properties of the VH and five commercial vitreous substitutes currently used in vitreoretinal surgeries. Six fluids were analysed: VH collected from rabbit eyes, two silicone oils (RS-Oil1000 and RS-Oil5000, Alchimia), two perflurocarbon liquids (HPF8 and HPF10, Alchimia) and a mixture of silicone oil with perfluorocarbon (Densiron68, Fluoron). The rheological characterization of the fluids was done using a shear rheometer (DHR-2, TA Instruments) to perform steady shear, small amplitude oscillatory shear (SAOS) and creep measurements. Extensional measurements using the Slow Retraction Method were performed with a capillary break-up extensional rheometer (Haake CaBER1, ThermoElectron) and an in-house extensional rheometer. Our results show that VH separates into two different phases (gel and liquid) and both phases exhibit viscoelastic behaviour. The liquid phase rheology is independent of time but the gel properties are time dependent, with the VH gel phase exhibiting storage (G’) and loss (G’’) moduli that increase with time after dissection (e.g. the maximum value of G’ and G’’ increase from 3.2 Pa and 0.9 Pa right after dissection to 11.4 Pa and 2.3 Pa a few hours after dissection). Despite being used for the same purpose, the pharmacological fluids show significantly different rheological properties between them and when compared with the VH. All pharmacological fluids tested display a Newtonian behaviour in steady shear flow and their viscosities vary from 0.49 mPa s to 4.57 Pa s, at 37°C

Validation of an empirical model for grapevine leaf area estimation with data from the varieties ‘Cannonau’ and ‘Vermentino’ grown in Sardinia

The performance of two mathematical models for non-destructive estimation of primary and lateral leaf area per shoot of Tempranillo grapevines was tested in Sardinia using independent datasets from two main traditional varieties. One collected on Cannonau grapevines from Nurra wine region, and another from Vermentino grapevines grown in Gallura wine region. The models presented good fit between observed and estimated values with high modeling efficiency. For primary leaf area estimation the mean absolute percent error for both varieties was lower than 10%. Both linear regressions between observed and estimated primary leaf area had high and significant R2 but while Vermentino fitted line presented a slope not significantly different from 1, Cannonau fitted line showed a slope significantly < 1, indicating that the model overestimated the primary leaf area per shoot. The validation of the model for lateral leaf area presented lower goodness of fit as that reported for primary leaf area. Linear regressions had a very high and significant R2 but the slopes were significantly <1 indicating that the model overestimated lateral leaf area per shoot. The positive validation shows that these models can accurately predict leaf area per shoot independently of ecological conditions, variety, year, growth stage and training system. Low goodness of fit for lateral leaf area model may be avoided building the model on each variety data. The generalized use of this type of model represents a powerful tool for grapevine research, for consultants and advanced growers, allowing the evaluate vine leaf area more frequently and with low costinfo:eu-repo/semantics/publishedVersio

A New Age for Quercus spp. Fruits: Review on Nutritional and Phytochemical Composition and Related Biological Activities of Acorns

The current global food system must adapt to the expected growth of world population (about 9 billion individuals by 2050). This adaptation will probably include an increased consumption of edible wild foods, due to their richness in micronutrients and bioactive compounds, besides providing a cost-effective and sustainable way of improving caloric food security. A striking example of such natural matrices is the Quercus genus, which has the additional advantage of being widespread throughout the Northern Hemisphere. In a traditional sense, Quercus fruits (acorns) were mainly used in animal feeding, despite their potentially important role on the rural economy. But this preconception is changing. In fact, their nutritional value, high contents in phytochemical compounds, biological activity (such as antioxidant, anticarcinogenic, and cardioprotective properties) and use in the treatment of specific diseases (such as atherosclerosis, diabetes, or Alzheimer's disease) have raised the interest in integrating acorns into the human diet. Accordingly, this comprehensive overview was designed to provide an evidence-based review of the literature, with the objective to achieve useful conclusions regarding the nutritional properties, methodologies of extraction, identification, and characterization of a wide variety of bioactive compounds and scientifically validated bioactivities in Quercus species worldwide. The industrial by-products from acorn oil extraction or flour production are also included. Data regarding the analytical techniques, individual compounds, and their bioactivities, are organized in tables. The reported data are discussed and directions for further investigations are suggested, highlighting the use of acorns in food, nutraceutical, and pharmaceutical applications.The authors are grateful for the financial support (UID/QUI/ 50006/2013-POCI/01/0145/FEDER/007265) from FCT/ MEC through national funds and cofinanced by FEDER, under the Partnership Agreement PT2020. J.C.M. Barreira thanks FCT, POPH-QREN, and FSE for his grant (SFRH/BPD/72802/ 2010). The authors thank Telma Oliveira for drawing the acorn sketch depicted in Figure 1.info:eu-repo/semantics/publishedVersio

Computational model to predict the temperature distribution produced by bone cement

Bone is the third frequent location for haematogenous dissemination of malignant tumors. Patients with multiple bone metastases are exponentially growing. Bone metastases, which are frequently diagnosed late, are associated to imminent and pathological bone fractures. Metastatic disease translates an advanced tumor stage and it has a high impact in patients’ quality of life and survival. The main objective is to study the thermal effect induced by the bone cement polymerization, in the bone metastatic tumor reduction and to understand the role of such procedure and its biomechanical stabilization. To assess the clinical effect, it is important to test this methodology before its application and obtain sustained results. In this work, a computational model was developed to predict the temperature distribution produced by cement polymerization, and verify the reduction of the metastatic tumor area due the thermal effect. Different simulations produced to evaluate the necrosis effect for two cement amount sizes introduced in a cortical and spongy bone tumor. The same computational models were reproduced introducing an endomedular nail in titanium and a femoral stem in cobalt-chrome material in pathological bone fractures.info:eu-repo/semantics/publishedVersio

Suministro De La Demanda De Energía En El Procesamiento De Carne De Pollo Con Biogás

The main use of electrical energy in the chicken meat processing unit is refrigeration. About 70% of the electricity is consumed in the compressors for the refrigeration system. Through this study, the energetic viability of using biogas from poultry litter in supplying the demand for the refrigeration process was found. The meat processing unit studied has the potential to process about a hundred and sixty thousand chickens a day. The potential biogas production from poultry litter is 60,754,298.91 m3.year-1. There will be a surplus of approximately 8,103 MWh per month of electric energy generated from biogas. An economic analysis was performed considering a planning horizon of 20 years and the discount rate of 12% per year. The economic analysis was performed considering scenario 1: sale of all electricity generated by the thermoelectric facility, and scenario 2: sale of the surplus electricity generated after complying with the demands of the refrigeration process and all other electrical energy and thermal energy use. Economic indicators obtained for scenarios 1 and 2 were favorable for the project implementation. © 2016, Revista Ingenieria e Investigacion - Editorial Board. All Rights reserved.36111812

Baobab: uma fonte natural de vitamina C

Introdução: As vitaminas distinguem-se de outros constituintes dietéticos por, em quantidades mínimas, beneficiarem diversos processos metabólicos. A vitamina C (ácido L-ascórbico), presente em frutas e legumes, é fundamental para a nutrição humana, por ser um antioxidante natural. No entanto, os teores do ácido L-ascórbico, principal forma biologicamente ativa desta vitamina, decrescem significativamente ao longo do amadurecimento dos alimentos. O conhecimento da composição nutricional e fitoquímica de frutos exóticos, caso da múcua (Baobab), pode dar a conhecer novas fontes de bioativos e permitir a sua valorização, contribuindo para a sustentabilidade social e económica da região de origem. Objetivos: Análise quantitativa do teor total de vitamina C da polpa do fruto da Adansonia digitata L., conhecida Baobab, espécie nativa de África. Métodos: O teor de ácido ascórbico foi determinado por HPLC-DAD, segundo um método previamente validado. 2 g de amostra foram adicionados a 12 mL de solução estabilizadora (ácido perclórico 10%, v/v) + ácido metafosfórico 1%, p/v). Para a determinação do teor de vitamina C total, utilizou-se tris(2-carboxietil) fosfina (5 mM). O teor de ácido desidroascórbico (forma biologicamente menos ativa) foi determinado por diferença. Resultados: O teor total de vitamina C foi de 26,1 mg/100 g, sendo 22,8 mg/100 g de ácido L-ascórbico e 3,33 mg/100 g de ácido desidroascórbico. Embora estes valores sejam significativamente inferiores aos descritos na laranja (49,1 mg/100 g) e no kiwi (55,2 mg/100 g), este fruto tem um período de conservação substancialmente maior. Atendendo aos seus teores reduzidos de humidade, o Baobab pode ser uma alternativa natural rica em antioxidantes. Conclusões: Este estudo salienta o potencial efeito antioxidante de uma fruta tropical pouco estudada e apenas consumida pela população local. A estabilidade do teor de ácido L-ascórbico observada no Baobab promove novas perspetivas de exploração e utilização de recursos naturais, no âmbito das ciências da nutrição

Perceived cognitive functioning in breast cancer patients treated with chemotherapy compared to matched healthy women: Evidence from a Portuguese study

Aim: Cognitive concerns are one of the most frequently reported symptoms by breast cancer survivors. This study aimed to evaluate perceived cognitive functioning in Portuguese women with breast cancer treated with chemotherapy. Methods: A cross-sectional study enrolling 146 women (73 with breast cancer and 73 healthy) was conducted from August to October 2017, invited to participate through online dissemination. Participants completed self-reported questionnaires to collect sociodemographic and clinical data and assess perceived cognitive functioning and psychological adjustment variables (anxiety and depression). Results: Compared to healthy women, women with breast cancer showed significantly lower scores on the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) subscales and higher levels of depression. Both groups showed significant negative correlations between perceived cognitive functioning and anxiety and depression. Health status and depression seem to better explain perceived cognitive functioning, with health status adding significantly more explained variance beyond sociodemographic and psychological adjustment variables. Conclusion: The current findings provide evidence for the existence of more cognitive complaints among Portuguese women with breast cancer, compared to healthy individuals. Anxiety, depression, age and education also explain perceived cognitive functioning. Considering that health status and psychological adjustment seem to significantly explain perceived cognitive functioning, special attention should be given by health-care professionals, including nurses, to designing clinical interventions for breast cancer patients to help manage cognitive impairment

Development and evaluation of an HPLC/DAD method for the analysis of phenolic compounds from olive fruits

A new HPLC/DAD methodology for separating nine phenolic compounds is described. This methodology is applied to the definition of qualitative and quantitative profiles of three Portuguese olive fruit cultivars (Cobrançosa, Madural and Verdeal). Two different extraction methods were needed for the complete definition of their profiles, one of them including a Sep-pack C18 cleaning step. The chromatographic separation was achieved using a Spherisorb ODS2 (25.0 × 0.46 cm; 5 μm, particle size) column. The solvent system used was a gradient of water-formic acid (19:1) and methanol, with a flow rate of 0.9 mL/min. The detection limit values for phenolic compounds were between 0.04 and 4.32 μg/mL and the method was precise. As a general rule, the recovery values were high. This technique can also be useful in the discrimination of Portuguese olive fruit cultivar

The Network of Scientific Collaborations within the European Framework Programme

We use the emergent field of Complex Networks to analyze the network of scientific collaborations between entities (universities, research organizations, industry related companies,...) which collaborate in the context of the so-called Framework Programme. We demonstrate here that it is a scale--free network with an accelerated growth, which implies that the creation of new collaborations is encouraged. Moreover, these collaborations possess hierarchical modularity. Likewise, we find that the information flow depends on the size of the participants but not on geographical constraints.Comment: 13 pages, 6 figure