Insights into the Structure and Protein Composition of Moorella thermoacetica Spores Formed at Different Temperatures

The bacterium Moorella thermoacetica produces the most heat-resistant spores of any spoilage-causing microorganism known in the food industry. Previous work by our group revealed that the resistance of these spores to wet heat and biocides was lower when spores were produced at a lower temperature than the optimal temperature. Here, we used electron microcopy to characterize the ultrastructure of the coat of the spores formed at different sporulation temperatures; we found that spores produced at 55 °C mainly exhibited a lamellar inner coat tightly associated with a diffuse outer coat, while spores produced at 45 °C showed an inner and an outer coat separated by a less electron-dense zone. Moreover, misarranged coat structures were more frequently observed when spores were produced at the lower temperature. We then analyzed the proteome of the spores obtained at either 45 °C or 55 °C with respect to proteins putatively involved in the spore coat, exosporium, or in spore resistance. Some putative spore coat proteins, such as CotSA, were only identified in spores produced at 55 °C; other putative exosporium and coat proteins were significantly less abundant in spores produced at 45 °C. Altogether, our results suggest that sporulation temperature affects the structure and protein composition of M. thermoacetica spores.

Perfecting Straddle Packer Microfrac Stress Contrast Measurements for Hydraulic Fracturing Design in UAE Tight Oil Reservoir

The objective of this work was to quantify the in-situ stress contrast between the reservoir and the surrounding dense carbonate layers above and below for accurate hydraulic fracturing propagation modelling and precise fracture containment prediction. The goal was to design an optimum reservoir stimulation treatment in a Lower Cretaceous tight oil reservoir without fracturing the lower dense zone and communicating the high-permeability reservoir below. This case study came from Abu Dhabi onshore where a vertical pilot hole was drilled to perform in-situ stress testing to design a horizontal multi-stage hydraulic fractured well in a 35-ft thick reservoir. The in-situ stress tests were obtained using a wireline straddle packer microfrac tool able to measure formation breakdown and fracture closure pressures in multiple zones across the dense and reservoir layers. Standard dual-packer micro-injection tests were conducted to measure stresses in reservoir layers while single-packer sleeve-frac tests were done to breakdown high-stress dense layers. The pressure versus time was monitored in real-time to make prompt geoscience decisions during the acquisition of the data. The formation breakdown and fracture closure pressures were utilized to calibrated minimum and maximum lateral tectonic strains for accurate in-situ stress profile. Then, the calibrated stress profile was used to simulate fracture propagation and containment for the subsequent reservoir stimulation design. A total 17 microfrac stress tests were completed in 13 testing points across the vertical pilot, 12 with dual-packer injection and 5 with single-packer sleeve fracturing inflation. The fracture closure results showed stronger stress contrast towards the lower dense zone (900 psi) in comparison with the upper dense zone (600 psi). These measurements enabled the oilfield operating company to place the lateral well in a lower section of the tight reservoir without the risk of fracturing out-of-zone. The novelty of this in-situ stress testing consisted of single packer inflations (sleeve frac) in an 8½-in hole in order to achieve higher differential pressures (7,000 psi) to breakdown the dense zones. The single packer breakdown permitted fracture propagation and reliable closure measurements with dual-packer injection at a lower differential reopening pressure (4,500 psi). Microfracturing the tight formation prior to fluid sampling produced clean oil samples with 80% reduction of pump out time in comparison to conventional straddle packer sampling operations. This was a breakthrough operational outcome in sampling this reservoir.

The Impact of Power on Contact Zones and Receptivity

The concept of contacts zones, as developed in Ulf 2009, employs differentiating factors to embed the actors involved in the transfers of goods and ideas in their cultural and socio-political environments. Power exerted between people who transfer goods and ideas and those who receive them, is decisive for how receptivity is shaped by their recipients. To discover where power is situated in the complex processes of intercultural interactions, this paper leads attention to the societal characteristics that have an impact on the cultural actors. Referring to the change from the Greek enoikismoi within the scattered settlements of the local population(s) in the hinterland between the Gulf of Taranto and Brindisi to the emergence of recognizable Greek settlements along the coastline from the 8th to the 7th century BC, the example of the feast is chosen to highlight the accompanying change of the scale of power and its exertion. In the terminology of contact zones, a dense contact zone lacking a dominant partner turns into a Middle Ground. From the definition of the various contact zones derives, that the receptivity changed from free adaptation of so far unknown cultural elements to their own intentions and needs to conscious and intentional misunderstandings of the other’s cultural forms and behaviour to gain advantage over the exchange partner. Thus power is a growing factor in their relationship and becomes the more important when the Middle Ground is replaced by a dense zone of contact where one partner is able to dominate. Thereby, it becomes clear that the relationships in cultural transfers are not tied up with ethnic conditions or cultural superiority and inferiority, but determined by the type of contact zones which in turn are characterized by the tools of power involved.

Attenuation study of a clay-rich dense zone in fractured carbonate reservoirs

Seismic attenuation in clay-rich dense zones remains unknown, despite the importance of such zones in hydrocarbon reservoirs, where they delimit the reservoir zones and isolate them from nearby aquifers. We have determined that a dense zone separating two carbonate reservoirs of an onshore oilfield in Abu Dhabi, United Arab Emirates, exhibits the highest intrinsic attenuation even though the zone contains no hydrocarbons. The frictional movement due to the elastic contrast between the hard carbonates and soft clay is most likely the dominant mechanism in the dense zone. The compressional sonic and vertical seismic profile (VSP) attenuation are on the same order of magnitude and are both maximum in the dense zone. Therefore, it is possible that the same attenuation mechanism in this zone exists at low and high frequencies; whereas the intrinsic attenuation mechanism in the reservoir zones, which are more permeable and porous than the dense zone, can be explained by the coexistence of global and squirt-flow mechanisms. Moreover, sonic attenuation exhibits higher magnitudes than VSP attenuation in these zones. This is due to the fact that the squirt-flow mechanism, which can take place between pores and fractures, is more important at sonic frequencies. The scattering mechanism is also important in the reservoir zones; this is due to the high heterogeneity and the presence of fractures in these zones.

Early differentation of lamellar structure of the intervertebral disc in staged human embryos

Introduction. In the vast literature concerning the development of the intervertebral discs controversies exist as to the period of differentiation and structure of the nucleus pulposus and annulus fibrosus. These controversies result from different determination of age of the investigated embryos. Aim. Using embryos from departmental collection age of which was established according to international Carnegie staging and expressed in postfertilizational days, the differentiation of the intervertebral discs was traced. Material and methods. Study was performed on 34 embryos at developmental stages 13–23 (32–56 days). Embryos were serially sectioned in sagittal, frontal and horizontal planes. Sections were stained with various histological methods and impregnated with silver.Results. Division of sclerotomes into loose cranial and dense caudal zones (sclerotomites) was observed in embryos aged 32 days (stage 13). The intervertebral disc developed from the dense zone of sclerotome and was well recognized in embryos aged 33 days (stage 14). At the end of fifth week (embryos at stage 15, 36 days) the annulus fibrosus and the nucleus pulposus were seen. The annulus fibrosus differentiated into lateral and medial zones. Within the lateral zone cells were arranged into circular rows. These rows were considered as the first stage of laminar structure. In further developmental stages the laminae occupied both zones of the annulus fibrosus.Conclusions. The intervertebral discs develop from the dense zone of the sclerotome which is evident in embryos at stage 13 (32 days). Discs differentiate in embryos aged 33 days, when the nucleus pulposus and annulus fibrosus are recognized. In embryos aged 36 days in the annulus fibrosus circular rows forming laminar arrangement are seen.

2D CFD Simulation of Hydrodynamics of the Dense Zone of a 65t/h High-Low Bed CFB

Gas-solid flow behavior of the bottom zone of a 65t/h High-low bed CFB was simulated using the commercial computational fluid dynamics (CFD) software package Fluent. The Eulerian-Eulerian model (EEM) based on the kinetic theory of granular flow (KTGF) was adopted. This approach treated each phase as continuous separately. The link between the gas and solid phases was through drag model and turbulence model. While the turbulence was simulated by the standard k-ε and mixture multiphase model, the Gidaspow drag model was used to model the interphase interaction. Four phases were set to achieve size distribution in the EEM. Gas and solid flow profiles are obtained for solid velocity, solid volume fraction, pressure, and size distribution. The results show that EEM can predict preferably the internal circulation process of the dense zone high-low bed CFB.