In vitro maintenance of Angiostrongylus costaricensis does not provide physiological conditions for egg laying

Fifteen pairs (male/female) of Angiostrongylus costaricensis were kept in vitro in Waymouth medium for three days to evaluate the amount and duration of egg laying. At 24, 48 and 72 hours, the mean egg counts were 321, 24 and 4 eggs/10 microliters, respectively. Most of the eggs were eliminated within the first 24 hours, suggesting they are expelled under non-physiological conditions. These results indicate that in vitro conditions are not appropriate for drug trials of egg-laying inhibitors for treatment of abdominal angiostrongylosis.

Amorphous silicon e 3D sensors applied to object detection

Nowadays, existing 3D scanning cameras and microscopes in the market use digital or discrete sensors, such as CCDs or CMOS for object detection applications. However, these combined systems are not fast enough for some application scenarios since they require large data processing resources and can be cumbersome. Thereby, there is a clear interest in exploring the possibilities and performances of analogue sensors such as arrays of position sensitive detectors with the final goal of integrating them in 3D scanning cameras or microscopes for object detection purposes. The work performed in this thesis deals with the implementation of prototype systems in order to explore the application of object detection using amorphous silicon position sensors of 32 and 128 lines which were produced in the clean room at CENIMAT-CEMOP. During the first phase of this work, the fabrication and the study of the static and dynamic specifications of the sensors as well as their conditioning in relation to the existing scientific and technological knowledge became a starting point. Subsequently, relevant data acquisition and suitable signal processing electronics were assembled. Various prototypes were developed for the 32 and 128 array PSD sensors. Appropriate optical solutions were integrated to work together with the constructed prototypes, allowing the required experiments to be carried out and allowing the achievement of the results presented in this thesis. All control, data acquisition and 3D rendering platform software was implemented for the existing systems. All these components were combined together to form several integrated systems for the 32 and 128 line PSD 3D sensors. The performance of the 32 PSD array sensor and system was evaluated for machine vision applications such as for example 3D object rendering as well as for microscopy applications such as for example micro object movement detection. Trials were also performed involving the 128 array PSD sensor systems. Sensor channel non-linearities of approximately 4 to 7% were obtained. Overall results obtained show the possibility of using a linear array of 32/128 1D line sensors based on the amorphous silicon technology to render 3D profiles of objects. The system and setup presented allows 3D rendering at high speeds and at high frame rates. The minimum detail or gap that can be detected by the sensor system is approximately 350 μm when using this current setup. It is also possible to render an object in 3D within a scanning angle range of 15º to 85º and identify its real height as a function of the scanning angle and the image displacement distance on the sensor. Simple and not so simple objects, such as a rubber and a plastic fork, can be rendered in 3D properly and accurately also at high resolution, using this sensor and system platform. The nip structure sensor system can detect primary and even derived colors of objects by a proper adjustment of the integration time of the system and by combining white, red, green and blue (RGB) light sources. A mean colorimetric error of 25.7 was obtained. It is also possible to detect the movement of micrometer objects using the 32 PSD sensor system. This kind of setup offers the possibility to detect if a micro object is moving, what are its dimensions and what is its position in two dimensions, even at high speeds. Results show a non-linearity of about 3% and a spatial resolution of < 2µm.

Fabrication and characterization of transparent conductive oxide surface sensors for electrocorticography – TrECoG

Understanding how the brain works has been one of the greatest goals of mankind. This desire fuels the scientific community to pursue novel techniques able to acquire the complex information produced by the brain at any given moment. The Electrocorticography (ECoG) is one of those techniques. By placing conductive electrodes over the dura, or directly over the cortex, and measuring the electric potential variation, one can acquire information regarding the activation of those areas. In this work, transparent ECoGs, (TrECoGs) are fabricated through thin film deposition of the Transparent Conductive Oxides (TCOs) Indium-Zinc-Oxide (IZO) and Gallium-Zinc-Oxide (GZO). Five distinct devices have been fabricated via shadow masking and photolithography. The data acquired and presented in this work validates the TrECoGs fabricated as efficient devices for recording brain activity. The best results were obtained for the GZO- based TrECoG, which presented an average impedance of 36 kΩ at 1 kHz for 500 μm diameter electrodes, a transmittance close to 90% for the visible spectrum and a clear capability to detect brain signal variations. The IZO based devices also presented high transmittance levels (90%), but with higher impedances, which ranged from 40 kΩ to 100 kΩ.

Estimate of Physiological Age in Females of PASSALUS (Insecta, Coleoptera)

Studies on development of female reproductive system insects have shown its utility in physiological age grading. The irreversible charocter of ovarian alterations correlated with mandibular wear and presence of yellow body, were applied to estimate the physiological age of Passalus convexus and Passalus latifrons females, giving results comparable to other studies and indicating the value of these methods in determination of physiological age.

Semantic architecture for sensors

Based on the report for the unit “Sociology of New Information Technologies” of the Master on Computer Sciences at FCT/University Nova Lisbon in 2015-16. The responsible of this curricular unit is Prof. António Moniz

Detection of dangerous situations using a smart internet of things system

The Internet of Things (IoT) is a concept that can foster the emergence of innovative applications. In order to minimize parents’s concerns about their children’s safety, this paper presents the design of a smart Internet of Things system for identifying dangerous situations. The system will be based on real time collection and analysis of physiological signals monitored by non-invasive and non-intrusive sensors, Frequency IDentification (RFID) tags and a Global Positioning System (GPS) to determine when a child is in danger. The assumption of a state of danger is made taking into account the validation of a certain number of biometric reactions to some specific situations and according to a self-learning algorithm developed for this architecture. The results of the analysis of data collected and the location of the child will be able in real time to child’s care holders in a web application.

The quantified-Self and wearable technologies in the workplace: implications and challenges for their implementations

Introduction of technologies in the workplace have led to a dramatic change. These changes have come with an increased capacity to gather data about one’s working performance (i.e. productivity), as well as the capacity to track one’s personal responses (i.e. emotional, physiological, etc.) to this changing workplace environment. This movement of self-monitoring or self-sensing using diverse types of wearable sensors combined with the use of computing has been identified as the Quantified-Self. Miniaturization of sensors, reduction in cost and a non-stop increase in the computer power capacity has led to a panacea of wearables and sensors to track and analyze all types of information. Utilized in the personal sphere to track information, a looming question remains, should employers use the information from the Quantified-Self to track their employees’ performance or well-being in the workplace and will this benefit employees? The aim of the present work is to layout the implications and challenges associated with the use of Quantified-Self information in the workplace. The Quantified-Self movement has enabled people to understand their personal life better by tracking multiple information and signals; such an approach could allow companies to gather knowledge on what drives productivity for their business and/or well-being of their employees. A discussion about the implications of this approach will cover 1) Monitoring health and well-being, 2) Oversight and safety, and 3) Mentoring and training. Challenges will address the question of 1) Privacy and Acceptability, 2) Scalability and 3) Creativity. Even though many questions remain regarding their use in the workplace, wearable technologies and Quantified-Self data in the workplace represent an exciting opportunity for the industry and health and safety practitioners who will be using them.

The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration

Abstract This study aimed to investigate the role of ascorbate peroxidase (APX), guaiacol peroxidase (GPX), polysaccharides, and protein contents associated with the early events of postharvest physiological deterioration (PPD) in cassava roots. Increases in APX and GPX activity, as well as total protein contents occurred from 3 to 5 days of storage and were correlated with the delay of PPD. Cassava samples stained with periodic acid-Schiff (PAS) highlighted the presence of starch and cellulose. Degradation of starch granules during PPD was also detected. Slight metachromatic reaction with toluidine blue is indicative of increasing of acidic polysaccharides and may play an important role in PPD delay. Principal component analysis (PCA) classified samples according to their levels of enzymatic activity based on the decision tree model which showed GPX and total protein amounts to be correlated with PPD. The Oriental (ORI) cultivar was more susceptible to PPD.

Development of polymer wicks for the fabrication of bio-medical sensors

Polymer based wicking structures were fabricated by sintering powders of polycarbonate (PC), ultra-high molecular weight polyethylene and polyamide 12, aiming at selecting a suitable material for an innovative electroencephalography (EEG) bio-electrode. Preliminary experiments showed that PC based wicks displayed the best mechanical properties, therefore more detailed studies were carried out with PC to evaluate the influence of powder granulometry and processing parameters (pressure, temperature and time) on the mechanical properties, porosity, mean pore radius and permeability of the wicks. It was concluded that the mechanical properties are significantly enhanced by increasing the processing time and pressure, although at the expense of a significant decrease of porosity and mean pore diameter (and thus permeability), particularly for the highest applied pressures (74kPa). However, a good compromise between porosity/permeability and mechanical properties could be obtained by sintering PC powders of particle sizes below 500μm at 165°C for 5min, upon an applied pressure of 56kPa. Moreover, PC proved to be chemically stable in contact with an EEG common used disinfectant. Thus, wicking structures with appropriate properties for the fabrication of reusable bio-electrodes could be fabricated from the sintering of PC powders.

Physiological responses of matrinxã (Brycon amazonicus) fed different levels of vitamin C and submitted to air exposure

The role of vitamin C on physiological responses of matrinxã (Brycon amazonicus) submitted to air exposure was analyzed. Nine hundred fish (70.15 g) were distributed in fifteen 500 l boxes (60 fish.box-1) and fed five rations (treatments): Control (no vitamin C); T100 (100 mg); T200 (200 mg); T400 (400 mg) and T800 (800 mg of vitamin C kg.ration-1). Each ration was offered to fish of three boxes during 60 days before the stress challenge that consisted of exposing fish to air for two minutes. Samplings were carried out for 5, 15, 30 and 60 minutes after the air exposure. Blood was collected for glucose, cortisol, total protein, sodium, chloride, hematocrit, hemoglobin determination, and white and red cell count. Liver was removed for hepatosomatic index (HSI) calculation and glycogen determination. Vitamin C did not affect the levels of cortisol, chloride, total protein, hemoglobin, leukocytes, hepatic glycogen or HSI in air exposed fish. Blood glucose levels elevation observed 60 minutes after the challenge did not depend on the levels of vitamin C, nor did the drop in serum sodium levels verified 60 minutes after stressor. In general, hematocrit did not change by effect of vitamin C but it was lower at 15 and 30 minutes after the challenge. The number of erythrocytes decreased in fish after 5 minute sampling in all treatments, especially at 30 and 60 minutes. The air exposure evoked alterations in stress indicators of matrinxã, and the vitamin C did not alter the responses.

Sodium chloride added to transport water and physiological responses of Matrinxã Brycon amazonicus (Teleost: Characidae)

The addition of salt to the water has been used to mitigate stress and improve survival in fishes. This study investigated the effects of sodium chloride (0.0, 1.0, 3.0 and 6.0 g/l) on levels of plasma cortisol, glucose, tryacilglycerol, total protein, hematocrit, hemoglobin, erythrocyte number, liver glycogen and lipid, and muscle lipid in adult matrinxã(Brycon amazonicum) after a 4-h transport and during a 96-h recovery period. Fish were sampled before and after transport, and 24 and 96 h of the recovery period. Plasma cortisol was higher than initial condition immediately after transportation, except in fish transported in 3.0 and 6.0 g/l of salt. A similar pattern was observed for blood glucose but fish transported in water with 0.0, 1.0 and 3.0 g/l of salt needed more than 24 h to return to the initial condition. Liver glycogen was lower after transport in fish not exposed to salt. Hemoglobin, erythrocyte number, total plasma protein and liver lipid did not change during the experiment but hematocrit was lower after transport in all treatments and returned to pre-transport values in 24 h. Reductions of muscle lipid and plasma tryacilglycerol were observed during the recovery period in fish from all treatments. The results show that 6.0 g/l NaCl added to the transport water reduce the stress responses and a 96-h recovery period is needed if no salt is used to mitigate the stress.

Physiological responses of pirarucu (Arapaima gigas) to acute handling stress

Pirarucu (Arapaima gigas) is an obligatory air-breathing fish from the Amazon basin. Previous study showed that pirarucu juveniles present a latency period in their response to moderate stress (transportation). Therefore the objective of this study was to verify the effects of a prolonged air exposure stress in lactate, glucose, cortisol, haematocrit, haemoglobin, and liver glycogen in pirarucu. Thirty-six fish were handled by netting and subjected to air exposure for 75-min. Six fish were sampled before handling and at 0, 6, 24, 48, and 96h after handling. Fish cortisol, lactate and haematocrit rose after handling, returning to previous unstressed values on the following sampling (6h after handling). Glucose increased significantly after handling and that was maintained for 24 h. There were no changes in haemoglobin and liver glycogen as a consequence of handling. The results demonstrate a quick response when exposed to an acute stressor and a fast recovery, suggesting that pirarucu does not use their glycogen reserves during an acute stress. The results suggest that pirarucu exhibit physiological stress responses to handling similar in magnitude to those previously documented for many teleostean fishes, including salmonids.

Towards "green" smart materials for force and strain sensors: The case of polyaniline

Stress/strain sensors constitute a class of devices with a global ever-growing market thanks to their use in many fields of modern life. They are typically constituted by thin metal foils deposited on flexible supports. However, the low inherent resistivity and limited flexibility of their constituents make them inadequate for several applications, such as measuring large movements in robotic systems and biological tissues. As an alternative to the traditional compounds, in the present work we will show the advantages to employ a smart material, polyaniline (PANI), prepared by an innovative environmentally friendly route, for force/strain sensor applications wherein simple processing, environmental friendliness and sensitivity are particularly required.

Physiological stress responses in the warm-water fish matrinxã (Brycon amazonicus ) subjected to a sudden cold shock

The present work evaluated several aspects of the generalized stress response [endocrine (cortisol), metabolic (glucose), hematologic (hematocrit and hemoglobin) and cellular (HSP70)] in the Amazonian warm-water fish matrinxã (Brycon amazonicus ) subjected to an acute cold shock. This species farming has been done in South America, and growth and feed conversion rates have been interesting. However, in subtropical areas of Brazil, where the water temperature can rapidly change, high rates of matrinxã mortality have been associated with abrupt decrease in the water temperature. Thus, we subjected matrinxã to a sudden cold shock by transferring the fish directly to tanks in which the water temperature was 10ºC below the initial conditions (cold shock from 28ºC to 18ºC). After 1h the fish were returned to the original tanks (28ºC). The handling associated with tank transfer was also imposed on control groups (not exposed to cold shock). While exposure to cold shock did not alter the measured physiological conditions within 1h, fish returned to the ambient condition (water at 28º C) significantly increased plasma cortisol and glucose levels. Exposure to cold shock and return to the warm water did not affect HSP70 levels. The increased plasma cortisol and glucose levels after returning the fish to warm water suggest that matrinxã requires cortisol and glucose for adaptation to increased temperature.

Inkjet printing technology for flexible pressure sensors

Tese de Doutoramento Ciência e Engenharia de Polímeros e Compósitos.