Porous graphitic carbon (PGC) is an important tool in a chromatographer's armory that retains polar compounds with mass spectrometry (MS)-compatible solvents. However, its applicability is severely limited by an unpredictable loss of retention, which can be attributed to contamination. The solutions offered fail to restore the original retention and our observations of retention time shifts of ...

INTRODUCTION Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chro...

This paper demonstrates how a complex model like the IWA Anaerobic Digestion Model no. 1 can be applied to gain more insight in the anaerobic process and particularly in the dynamics of the digester. The illustrated modelling approach avoids laborious measurements to characterise the influent according the extensive list of components defined in the model. It rather uses the model to make a bet...

To estimate tag retention time, 39 acoustic transmitters were hand-fed to bull sharks Carcharhinus leucas, lemon sharks Negaprion acutidens and tiger sharks Galeocerdo cuvier, in the Shark Reef Marine Reserve, Fiji. Minimum tag retention times ranged from less than 24 h to 34 days, and bull sharks could be tracked for a minimum mean duration of 6.8 days. Feeding acoustic transmitters wrapped in...

Background HIV remains a major public health challenge in Zambia. The roll-out of antiretroviral treatment (ART) has engendered new challenges in retention in care. Objective To conceptualise the factors affecting retention in care of ART patients at three primary healthcare facilities using the ecological framework. Method Qualitative data were collected through in-depth interviews with 45...

Some food characteristics, like stickiness and consistency, can modify the time for food removal from the mouth as well as favors the activity of cariogenic bacteria, increasing dental caries risk. This study aimed to observe food retention in contact with a cariogenic substrate in 24-30 months old children. Therefore, 27 children (54 teeth) were evaluated. They intake a chocolate cookie and th...

In this investigation the denture retention was measured and the influence of denture -retention on ima'sticatory efficiency was examined. The investigation was iperf armed on 36 comiplete denture wearers. The test of masticatory efficiency wals used according to Ni'kšić (1965). The meaisuriinig of denture retention was made by specially constructed mechanical scale, which wa's designed so that...

In recent years capillary electrophoresis (CE) has been used routinely in many laboratories. Many rugged methods have been developed which utilize extensive capillary flushing and preconditioning steps to ensure constant run-to-run starting conditions, constant electro osmotic flow (EOF) and reproducible migration times. However, due to reliance on the EOF, in contrast to a constant pumping sys...