Three-Dimensional Acoustic Device for Testing the All-Directional Anisotropic Characteristics of Rock Samples.

Many oil and gas fields, especially non-conventional shale and compacted sand reservoirs, have formation anisotropy. The acoustic anisotropy measurement of cores in these reservoirs can guide drilling, well logging, and exploitation. However, almost all core holders are designed for cylinder cores, which are not suitable for all-directional measurements. A three-dimensional measurement device was designed on the basis of the cross-hole sonic logging method. This device mainly consisted of two pairs of transducers, a signal generator, an oscillograph, an omnidirectional positioning system, and a computer control system. By adjusting the measurement latitude and longitude circle automatically, this device scanned spherical sample rocks and obtained full-wave waveforms in all directions. Experiments were performed taking granite from the Jiaodong Peninsula, China, as an example, and the arrival times and velocities of the longitudinal and shear waves were calculated based on the full-wave waveforms. Thereafter, anisotropic physical characterizations were carried out on the basis of these velocities. These data play an important role in guiding formation fracturing and analyzing the stability of borehole walls.

Dynamic structural changes in microbial membranes in response to high hydrostatic pressure analyzed using time-resolved fluorescence anisotropy measurement.

High hydrostatic pressure has a profound physiological impact on lipid membranes, primarily resulting in tighter packing and restriction of acyl-chain motion. To fulfill membrane protein functions in high-pressure environments, deep-sea organisms possess specialized cell membranes. Although the effects of high-pressure on model membranes have been investigated in great detail, high-pressure-induced structural changes in living cell membranes remain to be elucidated. Of the spectroscopic techniques available to date, fluorescence anisotropy measurement is a common useful method that provides information on dynamic membrane properties. This mini-review focuses on pressure-induced changes in natural cell membranes, analyzed by means of high-pressure time-resolved fluorescence anisotropy measurement (HP-TRFAM). Specifically, the role of eicosapentaenoic acid in deep-sea piezophiles is described in terms of the structural integrity of the membrane under high pressure.

Growth, fatty acid profile in major lipid classes and lipid fluidity of Aurantiochytrium mangrovei Sk-02 as a function of growth temperature

Aurantiochytrium mangrovei Sk-02 was grown in a medium containing glucose (40 g/l), yeast extract (10 g/L) and sea salts (15 g/L) at temperatures ranging from 12 to 35°C. The fastest growth (µmax= 0.15 h-1) and highest fatty acid content of 415 mg/g-dry cell weight were found in the cells grown at 30°C. However, the cells grown at 12°C showed the highest percentage of polyunsaturated fatty acid (PUFA) (48.6% of total fatty acid). The percentage of docosahexaenoic acid (DHA) and pentadecanoic acid (C15:0) decreased with an increase in the growth temperature, whereas, palmitic acid (C16:0), stearic acid (C18:0) and DPA (C22:5n6) increased with an increase in the growth temperature. The composition of the major lipid class (%w/w) was slightly affected by the growth temperature. The fluidity of the organelle membrane or intracellular lipid (by DPH measurement) decreased with an increase in the growth temperatures, while the plasma membrane fluidity (by TMA-DPH measurement) could still maintain its fluidity in a wide range of temperatures (15 - 37°C). Furthermore, the distribution of DHA was found to be higher (36 - 54%) in phospholipid (PL) as compared to neutral lipid (NL) (20 - 41%).

Growth, fatty acid profile in major lipid classes and lipid fluidity of Aurantiochytrium mangrovei SK-02 As a function of growth temperature.

Aurantiochytrium mangrovei Sk-02 was grown in a medium containing glucose (40 g/l), yeast extract (10 g/L) and sea salts (15 g/L) at temperatures ranging from 12 to 35°C. The fastest growth (µmax= 0.15 h(-1)) and highest fatty acid content of 415 mg/g-dry cell weight were found in the cells grown at 30°C. However, the cells grown at 12°C showed the highest percentage of polyunsaturated fatty acid (PUFA) (48.6% of total fatty acid). The percentage of docosahexaenoic acid (DHA) and pentadecanoic acid (C15:0) decreased with an increase in the growth temperature, whereas, palmitic acid (C16:0), stearic acid (C18:0) and DPA (C22:5n6) increased with an increase in the growth temperature. The composition of the major lipid class (%w/w) was slightly affected by the growth temperature. The fluidity of the organelle membrane or intracellular lipid (by DPH measurement) decreased with an increase in the growth temperatures, while the plasma membrane fluidity (by TMA-DPH measurement) could still maintain its fluidity in a wide range of temperatures (15 - 37°C). Furthermore, the distribution of DHA was found to be higher (36 - 54%) in phospholipid (PL) as compared to neutral lipid (NL) (20 - 41%).