Successful outcome after spontaneous first trimester intra-amniotic haematoma and early preterm premature rupture of membranes

A spontaneous intra-amniotic haematoma is a rare cause of preterm premature rupture of the membranes (PPROM) but can have significant fetal and maternal consequences. It has previously been reported to occur in the second and third trimesters but not in an earlier gestation. We present a case that presented acutely in the first trimester of pregnancy, which leads to early PPROM at 15 weeks and spontaneous preterm delivery at 28 weeks of gestation. There were no maternal complications during the pregnancy

Swelling and hydration studies on egg yolk samples via scanning fluid dynamic gauge and gravimetric tests

AbstractHydration and swelling in initially dry protein-based samples represent the first stage in their cleaning from hard surfaces. These phenomena have been studied in technical egg yolk stains via scanning Fluid Dynamic Gauge (sFDG) and gravimetric tests. Temperature (30 °C to 55 °C) and pH (9.5 to 11.5) were investigated as factors influencing the process. The kinetics did not appear to be significantly different as 95% of the equilibrium swelling was reached at approximately 90 min in all tests. No removal of the egg yolk layer was observed in most cases, except at high alkaline conditions (pH 11.5), where a lift-up followed by a partial removal of the protein network was seen when an external shear stress was applied. The process mimicked creep behaviour of plastic materials. Gravimetric data on the hydration of the sample suggested a Fickian diffusion transport (Case I), where solvent diffusion is the rate limiting stage. The initial hydration was proved to be linear. Two diffusion theories of increasing complexity were applied to estimate effective diffusion coefficients: Fick's second law (with moving boundaries) and a non-linear poroelasticity theory. The temperature dependence of different diffusion coefficients assuming an Arrhenius equation gave an activation energy in the range of 16.4 (±6.7) KJ/mol to 18.4 (±9.0) KJ/mol

Microstructure and reconstitution of freeze-dried gum Arabic at a range of concentrations and primary drying temperatures

Freeze-drying is an energy intensive unit operation used for the production of dehydrated foods, such as instant coffee and dried fruits, and results in high sensorial, nutritional and reconstitution properties of the final products. Understanding the relationships between operating conditions and product quality is essential to design processes that are energy efficient, whilst producing high quality dried foods. In this work, the properties (microstructure and reconstitution) of freeze-dried gum arabic samples (with initial concentrations ranging between 20 and 60% solids by weight) were evaluated. The materials were dried at three different primary drying shelf temperatures, Ts (- 20, - 30 and - 40 ◦C). Sample temperatures recorded throughout freeze-drying were close to the pre-set Ts, with the exception of the 60% initial concentration system, where the sample was hotter than the shelf by 10–15 ◦C, in particular on increasing Ts. This was attributed to a combination of local temperature and pressure conditions that may have resulted in partial melting of the material. For the 20–50% systems, the properties of the freeze-dried materials were mainly affected by the initial concentration of the system, with increasing initial concentration generally resulting in lower porosities (ranging between 20 and 40%) and higher reconstitution times (ranging between 0.5 and 10min for 95% reconstitution). Pores were generally needle-shaped and <200 μm. Large (200–1800 μm), circular pores were observed in high initial concentration systems, and they were dominant in the microstructure of the freeze-dried 60% sample. The presence of these large bubbles was linked to the partial melting of the material, which enabled its expansion and puffing. For the 60% system, primary drying temperature had a profound effect on the properties of the freeze-dried solid, with samples dried at higher temperature showing higher porosity (e.g. 60–70% for Ts = -¬¬ 20◦C) and faster reconstitution rates (e.g. 3min for 95% reconstitution at Ts = - 20◦C). Overall, this study demonstrates the significance of formulation and shelf temperature on the porous structure of freeze-dried samples, which directly influences product performance

Statistics of low-energy levels of a one-dimensional weakly localized Frenkel exciton: A numerical study

Numerical study of the one-dimensional Frenkel Hamiltonian with on-site randomness is carried out. We focus on the statistics of the energy levels near the lower exciton band edge, i. e. those determining optical response. We found that the distribution of the energy spacing between the states that are well localized at the same segment is characterized by non-zero mean, i.e. these states undergo repulsion. This repulsion results in a local discrete energy structure of a localized Frenkel exciton. On the contrary, the energy spacing distribution for weakly overlapping local ground states (the states with no nodes within their localization segments) that are localized at different segments has zero mean and shows almost no repulsion. The typical width of the latter distribution is of the same order as the typical spacing in the local discrete energy structure, so that this local structure is hidden; it does not reveal itself neither in the density of states nor in the linear absorption spectra. However, this structure affects the two-exciton transitions involving the states of the same segment and can be observed by the pump-probe spectroscopy. We analyze also the disorder degree scaling of the first and second momenta of the distributions.Comment: 10 pages, 6 figure

Effect of freezing on microstructure and reconstitution of freeze-dried high solid hydrocolloid-based systems

Freeze-drying has been associated with high quality hydrocolloid-based products such as coffee. However, it is an expensive technique, and one way to reduce energy and water use is by drying concentrated systems. Controlling the ice crystal formation is important to produce final dried materials with desired microstructure and properties. This study presents the effect of freezing with and without temperature oscillations on the final microstructure and reconstitution of aerated and non-aerated freeze-dried concentrated (50 and 60% w/w) gum arabic and coffee systems. Samples were either frozen at -40 C or subjected to fluctuating temperatures between -40 and -20 C prior to drying. Thermal analysis of the systems showed lower nucleation and freezing temperatures for 50% compared to 60% solutions, as expected, and melting temperatures > -20 C. During drying, puffing of the material was observed, with appearance of a glass-like, puffed bottom layer, in particular for the 60% coffee frozen at -40 C. SEM micrographs revealed pores of dendritic, hexagonal, and circular shape, indicating voids produced by sublimation of ice crystals. Pore sizes were smaller (by 50%, of the order of 40ìm) for the 60%, than the 50% systems. Temperature fluctuations during freezing doubled the observed pore sizes and the apparent total porosity which effectively accelerated the dissolution kinetics. Aeration resulted in the appearance of air bubbles (diameter 200e1600 mm) that largely phase separated in gum arabic and resulted in faster rehydrating solids. This work demonstrates the potential of process design to control microstructural attributes and reconstitution properties of freeze-dried hydrocolloid-based products in systems with high solute concentrations

In silico modelling of mass transfer &amp; absorption in the human gut

AbstractAn in silico model has been developed to investigate the digestion and absorption of starch and glucose in the small intestine. The main question we are aiming to address is the relative effect of gastric empting time and luminal viscosity on the rate of glucose absorption. The results indicate that all factors have a significant effect on the amount of glucose absorbed. For low luminal viscosities (e.g. lower than 0.1 Pas) the rate of absorption is controlled by the gastric emptying time. For viscosities higher than 0.1 Pas a 10 fold increase in viscosity can result in a 4 fold decrease of glucose absorbed. Our model, with the simplifications used to develop it, indicate that for high viscosity luminal phases, gastric emptying rate is not the controlling mechanism for nutrient availability. Developing a mechanistic model could help elucidate the rate limiting steps that control the digestion process

Processing of barley grains in a continuous vibrating conveyor

AbstractA novel tubular industrial apparatus for the surface pasteurization of particles has been studied. Particles are conveyed through a helical pipe by vibrations created by off-balance motors. The residence time of barley grains was characterized. The behaviour of the system was a function of motor angle and motor speed. The residence time could vary up to 21% during one experiment of 2 h (20°, 740 rpm). However, ranges of processing conditions were identified that produce stable operation and thus effective pasteurization of product. In some cases, residence time increased by up to 7% of the initial value over consecutive experiments (40°, 710 rpm). Some reasons for this phenomenon have been proposed and tested. The formation of a powder layer inside the pipe has been proven to affect the residence time of barley grains. A simple model for pasteurization of particles has been developed to characterise the impact of variation in residence time on microbial inactivation

A systematic study of the residence time of flour in a vibrating apparatus used for thermal processing

AbstractThe dry heat treatment of flour is well established for the production of cake flour for high ratio cakes. This study investigates a new tubular apparatus in which flour is conveyed by vibrations through a helical pipe. Residence time distributions (RTDs) of flour were characterised for various processing conditions and the development of the residence time in extended operation was analysed.A method was developed to accurately determine the RTDs, which could be approximated by normal distributions. The width of the distributions is a critical factor for the accuracy of a thermal process and was identified for different processing conditions. The distributions were narrow, with variations of ±1% at most.In some cases, the residence time increased over 3.5h of machine run-time by 7.7%–13.9%. To explain this phenomenon, several hypotheses have been tested. The machine performance was constant with time and no influence of ambient temperature or humidity could be found. It was furthermore shown that changes in the bulk material passing through the apparatus were not the cause of the increase. However, electrostatic charging of the material was observed.Two things led to a reduction in residence time: i) cleaning the pipe with a cleaning pig and water and ii) time, during which the machine is not running. It was suggested that a thin layer of particles inside the pipe in combination with electrostatics effects could be the reason for the residence time increase. Frequent cleaning can therefore allow relatively uniform behaviour and control of residence time.Industrial relevanceThis work investigates the potential application of a novel, vibrating device for the dry heat treatment of flour as a replacement for chlorination in the production of cake flour. Since chlorination was banned in the EU in the year 2000, there is an industrial interest for alternative treatments and equipment to produce flour for high ratio cakes