Calcium-binding capacity of organic and inorganic ortho- and polyphosphates

The aim of this research was to determine the calcium-binding capacity of inorganic and organic ortho- and polyphosphates. This calcium-binding capacity can be used to influence the stability of, for example, casein micelles in dairy systems. Four phosphates were selected: disodium uridine monophosphate (Na2UMP, organic orthophosphate), disodium hydrogen phosphate (Na2HPO4, inorganic orthophosphate), sodium phytate (SP, organic polyphosphate), and sodium hexametaphosphate (SHMP, inorganic polyphosphate). Concentrations of up to 100 mmolL-1 phosphate were added to a 50 mmolL-1 CaCl2 solution. The samples were prepared at pH 8.0 and were analyzed before and after sterilization for calcium-ion activity, conductivity, pH, sediment, and turbidity. Both SHMP and SP are strong chelators, as calcium ions bind to these phosphates in the ratio of 3:1 and 6:1, respectively. Calcium ions also strongly bind to Na2HPO4, but in a ratio of 3:2 with insoluble Ca3(PO4)2 complexes as result. The equilibrium position of Na2UMP is not strong towards the chelated complex, and significant levels of free calcium and free phosphate can exist. An equilibrium constant of Lmol-1 was determined for calcium uridine monophosphate (CaUMP) complexes. Both calculation of the equilibrium constant and analysis on the CaUMP precipitate confirmed a reactivity of 1:1 between calcium and Na2UMP. The CaUMP complexes are well soluble at ambient temperature, and insoluble complexes appear after sterilization, because the solubility of CaUMP decreases during heating. Finally, we concluded that the structure of phosphate molecules determines their calcium-binding capacity rather than organic or inorganic origin of phosphate

The ‘Donor of the Future Project’ : first results and further research domains

Background: The Alliance of Blood Operators initiated a project labelled ‘Donor of the Future’. This study gives an overview of the project results, in particular with regard to country differences. Study Design and Methods: A large survey (N = 7663) among blood donors in six countries was conducted to analyse the effects of five global areas of change: (1) demographic change; (2) technological developments; (3) health innovations; (4) public, behavioural and attitudinal aspects; and (5) political, economic and environmental issues. Results: The main results exhibited similarities and differences between blood donors of the participating countries. Greater differences were found, for example, regarding technological developments. Whereas only blood donors from the UK and Australia would like to be informed via SMS, blood donors from all countries would like to be informed via email. Conclusion: Different priorities of donors have been uncovered. These differences give suggestions to improve the country-specific donor management. Furthermore, the key findings provide a comprehensive overview of major future research domains

Grazing of Zooplankton in the Oceanic Environment

48 pagesGrazing in the oceans, in general, refers to herbivores feeding on plant material. It is an important factor in determining primary production in the sea, and is difficult to estimate. Also, this energy transfer seems at least in part to be responsible for population changes which occur in the ocean. Since it is only in the coastal waters that other plant material besides the phytoplankton is abundant (seaweed) and that other zooplankton organisms besides the copepods are abundant (meroplankton: the planktonic larval stages of Mollusca, Echinodermata and worms), attention will be primarily focused on the relation between phytoplankton organisms and copepods. (Marshall and Orr, 1966b) Most experimental work has been done with cope pods, al though other plank tonic animals (Euphausids, Chaetognaths etc.) are abundant at certain places for part of the year. In order to understand the problems involved in studying the quantitative aspects of grazing, a general discussion of the patterns of feeding is necessary (Chapter I). The second chapter provides the theoretical background. (mathematical models) for a discussion of the methods used and measurements obtained in chapter three. The last chapter discusses grazing as it relates to the ecological problem of population control and evaluates the progress made in this area of research

On the Connection of Anisotropic Conductivity to Tip Induced Space Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs

The electronic properties of shallow acceptors in p-doped GaAs{110} are investigated with scanning tunneling microscopy at low temperature. Shallow acceptors are known to exhibit distinct triangular contrasts in STM images for certain bias voltages. Spatially resolved I(V)-spectroscopy is performed to identify their energetic origin and behavior. A crucial parameter - the STM tip's work function - is determined experimentally. The voltage dependent potential configuration and band bending situation is derived. Ways to validate the calculations with the experiment are discussed. Differential conductivity maps reveal that the triangular contrasts are only observed with a depletion layer present under the STM tip. The tunnel process leading to the anisotropic contrasts calls for electrons to tunnel through vacuum gap and a finite region in the semiconductor.Comment: 11 pages, 8 figure

Mental healthcare goes online:Practitioners' experiences of providing mental healthcare during the COVID-19 pandemic

The outbreak of the COVID-19 pandemic has necessitated sudden and radical changes in mental health care delivery, as strict social distancing and lockdown measures were imposed in the early phases of the pandemic. Almost overnight, practitioners were forced to transfer their face-to-face care practice to online means. To understand the implications of this drastic change for mental health care, and to improve the online care offerings, an online qualitative survey was held among mental health care professionals in Netherlands (n = 51). Our findings indicate that technological and usability problems pose a significant challenge, as do difficulties to establish rapport with clients. Moreover, not all mental health issues and treatment forms are equally amenable to online interaction. In contrast, in many instances, practitioners were positive about the effectiveness of treatment, and reported flexibility, a lower threshold for contact, and lack of travel time as advantages. Their most prominent needs concern better technological, organizational, and logistical support. It is critical that these needs are acted upon by institutions and governments. In addition, current results inform future research on the improvement of e-mental health technologies

Species rank of Isabela Oriole Oriolus isabellae and White-lored Oriole O. albiloris reinforced by song playback responses

Environmental BiologyConservation Biolog