Search results for "nutrient"

Distributions of oxygen, nutrient, and metabolic waste concentrations in multicellular spheroids and their dependence on spheroid parameters.

1991

The distribution of oxygen, nutrients and metabolic wastes in multicellular tumor spheroids and its dependence on the parameters characterizing the spheroid (i.e., spheroid geometry, diffusivity, and consumption/production rates of biological substances) have been investigated by a theoretical analysis: 1. Parameter dependence is qualitatively demonstrated and visualized. 2. Reduction of the number of variables by specific coordinate transformations made it possible to generate nomograms from which concentration distributions for any choice of parameter values may easily be obtained. In particular, these nomograms may also be used for estimating concentration profiles of metabolic waste pro…

Sicilian bottled natural waters: Major and trace inorganic components

2013

Sixteen bottled waters of various Sicilian brands, 11 natural mineral waters and five normal drinking waters, were analyzed for major and trace inorganic components by ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The bottled waters represent a variety of water types with significantly different compositions in terms of salinity, major components and trace elements. Chemically, they range from Ca–HCO3 and Ca–SO4 to Na–HCO3 types. Total dissolved solids ranges from 54 to 433 mg/L, total hardness from 25 to 238 mg/L CaCO3, and measured Na content from 5.7 to 57 mg/L. According to total dissolved ions, all the bottled waters were classified as…

Kinetics of nitrogen removal in a MBR nutrient removal activated sludge system

2006

The application of membrane bioreactor (MBR) technology to biological nutrient removal (BNR) activated sludge (AS) systems is limited and uncertainty exists as to the impact of the conditions induced by the membranes on the biologically mediated processes of nutrient removal. Two main conditions associated with MBRs are (1) high total suspended solids (TSS) concentrations (8–20 g/L) and (2) different selection pressures due to biomass retention not being based on settleability, compared with conventional systems with secondary settling tanks (SSTs). Recently, Ramphao et al. [1] concluded that incorporating membranes in BNR AS makes a profound difference to the design of the system. Previous…

Strategies to decrease water drainage and nitrate emission from soilless cultures of greenhouse tomato

2010

In the spring-summer season of 2005 and 2006, we explored the influence of three fertigation strategies (A–C) on the water and nitrogen use efficiency of semi-closed rockwool culture of greenhouse tomato conducted using saline water (NaCl concentration of 9.5 mol m−3). The strategies under comparison were the following: (A) crop water uptake was compensated by refilling the mixing tank with nutrient solution at full strength (with the concentrations of macronutrients equal or close to the corresponding mean uptake concentrations as determined in previous studies) and the recirculating nutrient solution was flushed out whenever its electrical conductivity (EC) surpassed 4.5 dS m−1 due to the…

Radioisotopic determination of l-carnitine content in foods commonly eaten in Western countries

2004

Abstract l -Carnitine is a vitamin-like nutrient essential for energy production and lipid metabolism in many organs and tissues such as skeletal muscle and heart. Even if l -carnitine can be synthesized, most of the carnitine present in human body is provided by food. Until now, no large study has been conducted where the content in l -carnitine of various foods was analyzed. The objective of this study was to determine the level of free l -carnitine present in food commonly consumed in Western countries. A radioisotopic assay was used to estimate l -carnitine content in raw and processed foods. From this study, it clearly appeared that meat products were the best sources for l -carnitine.…

Changes of Photosynthesis-Related Parameters and Productivity of Spring Oilseed Rape under Different Nitrogen and Sulphur Fertilizers Supply

2015

Fertilization with essential mineral elements is important to get high quality yield results. The lack of necessary mineral elements in soil can affect oilseed rape plant physiological functions, photosynthesis and plant productivity. Oilseed rape plants have high requirements for nitrogen and as oil crop – for sulphur. The aim of the investigation was to explain changes of chlorophyll a fluorescence parameters in spring oilseed rape leaves and yield changes under nitrogen and sulphur supply. During laboratory experiments changes of chlorophyll a fluorescence parameters and during field experiments changes of yield parameters under different nitrogen and sulphur supply were observed. Labora…

Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent

2012

This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achie…

Cultivation of granular sludge with hypersaline oily wastewater

2015

The time required to stabilise mature aerobic granules is rather variable. In addition, cultivation time and the structural characteristics of granules seem to be related to the nature of wastewater influent. Granular sludge has been used for the treatment of several industrial wastewaters, but nothing has been reported about wastewater characterized by the simultaneous presence of hydrocarbons and high chloride concentration. In this work, the authors analysed the granulation process and performance as well as the physical characteristics of aerobic granules in two Granular Sequencing Batch Airlift Reactors (GSBARs), fed with acetate-based synthetic wastewater in reactor 1 (R1) and with a …

Impact of micronutrients on oral and general health

2012

Food choices and environmental responsibility – protect the Baltic Sea

2012

‘The Baltic environment, food and health: from habits to awareness – FOODWEB’ is a project that aims to raise public awareness about the links between food quality and its origin, focusing on the Baltic Sea and its surroundings. Cultivation of food for humans and related production activities can impact negatively on the Baltic Sea, and aquatic food products from the Baltic Sea may cause problems to humans as a result of toxins in the marine environment. This is a circular problem in the Baltic ecosystem. The project is a part of Central Baltic IVA Programme 2007- 2013. Finland, Estonia and Latvia take part in the Foodweb-project. The population is projected to grow in Finland and decrease …