Effects of brown seaweed extract, silicon, and selenium on fruit quality and yield of tomato under different substrates.

Tomatoes (Lycopersicun esculentum L.) are an important group of vegetable crops that have high economical and nutritional value. The use of fertilizers and appropriate substrates is one of the important strategies that can assist in increasing the yield and quality of fruits. The present study aimed to investigate the effects of exogenous seaweed extract (Nizamuddinia zanardinii), silicon (Na2SiO3), and selenium (Na2SeO3) on quality attributes and fruit yield (FY) of tomato under palm peat + perlite and coco peat + perlite substrates. Seaweed extract significantly improved several of the fruit quality attributes such as total carbohydrate content, total soluble solids (TSS), and pH as well as the FY. The results showed that silicon (Si) (75 mg) was the best foliar spray treatment to enhance the fruit firmness (30.46 N), fruit volume (196.8 cm3), and FY (3320.5 g). The highest amount of plant yield (3429.33 g) was obtained by the interaction effects of silicon (75 mg L-1) under the effect of palm peat. The use of selenium (Se) led to improvements in flavor index (TSS/TA). Also, the application of palm peat + perlite substrate caused an increase in vitamin C (16.62 mg/100g FW), compared to other substrates (14.27 mg/100g FW). The present study suggested that foliar spray with seaweed extract and Si had beneficial effects on the quality and FY of tomatoes. Also, the palm peat substrate can be used as a good alternative to the coco peat substrate in the hydroponic system.

Mathematical simulation and prediction of tumor volume using RBF artificial neural network at different circumstances in the tumor microenvironment.

Uncontrolled proliferation of cells in a tissue caused by genetic mutations inside a cell is referred to as a tumor. A tumor which grows rapidly encounters a barrier when it grows to a certain size in presence of preexisting vasculature. This is the time when it has to find a way to go on the growth. The tumor starts to secrete tumor angiogenic factors (TAFs) and stimulate preexisting vessels to grow new sprouts. These new sprouts will find their way to the tumor in the extracellular matrix (ECM) by the gradient of TAF. As these new capillaries anastomose and reach tumor, fresh oxygen is available for the tumor and it will reinitiate the growth. Number of initial sprouts, distance of initial tumor cells from the vessel(s) and initial density of the tumor at the time of sprout formation are questions which are to be investigated. In the present study, the aim is to find the response of tumor cells and vessels to the reciprocal effects of each other in different circumstances in the tissue. Together with a mathematical formulation, a radial basis function (RBF) neural network is established to predict the number of tumor cells at different circumstances including size and distance of initial tumors from the parent vessel. A final formulation is given for the final number of tumor cells as a function of initial tumor size and distance between a parent vessel and a tumor. Results of this simulation demonstrate that, increasing the distance between a tumor and a parent vessel decreases the number of final tumor cells. Specially, this decrement becomes faster beyond a certain distance. Moreover, initial tumors in bigger domains must become much bigger before inducing angiogenesis which makes it harder for them to survive.

Modeling the central nervous system functionality in controlling the calf muscle activity during running with sport shoes.

Biological findings show that the activity of the calf muscle group is controlled by the central nervous system during running. The central nervous system tries to retain the peak values of the ground reaction force at constant levels as well as to minimize the vibration amplitude of soft tissues of the lower leg. Furthermore, these objectives are functions of stiffness and damping (compliance properties) of the calf muscle-tendon unit, especially gastrocnemius-Achilles. In this article, a new model for the calf muscle-tendon unit activity is presented in which the coefficients of stiffness and damping are exponential functions of the force produced at the Achilles tendon in the duration of stance phase, that is, they are time variant instead of having constant values. Then, the central nervous system functionality to control the activity of the muscle-tendon unit is formulated through definition of an optimization problem. This problem is solved by additionally considering the hardness of sport shoes. The muscle activity is indeed controlled via optimally adjusting two tuning parameters of the muscle-tendon unit model in terms of the hardness of shoes. This idea is examined separately for two running speeds. The results show the following: (1) The hardness of shoes affects the muscle activity. We find safe areas of the hardness parameters to design sport shoes. (2) When hard shoes are worn, the running speed has negligible effects on the tuning parameters, while with soft shoes the tuning parameters significantly change the muscle activity and the ground reaction force depended on running speed. (3) The ability of muscle in changing its compliance properties (specified by bound limits over the muscle-tendon unit tuning parameters) has the most influence in the safe area. (4) Rising running speed leads to a decrease in the safe area of shoes' parameters.