*Corresponding author e-mail: [email protected] **This work was supported by the Internal Grant Agency of the Czech University of Life Sciences Prague, Project No. 20163001, (2016). A b s t r a c t . Image analysis is widely used for monitoring seeds during germination, and it is often the final phase of germination that is subjected to the greatest attention. However, the initial phase of germina...

Spontaneous imbibition enables the elegant propelling of nano-flows because of the dominance of capillarity at small length scales. The imbibition kinetics are, however, solely determined by the static host geometry, the capillarity, and the fluidity of the imbibed liquid. This makes active control particularly challenging. Here we show for aqueous electrolyte imbibition in nanoporous gold that...

Embryos, excised from seed coats of soybeans (Glycine max Merr. cv. ;Wayne'), leak profusely during the first minutes of imbibition. A discontinuity of temperature/leakage patterns occurs between 10 and 15 C; as embryos imbibe at 10 C or lower, disproportionately more solutes leak out per unit of water imbibed. Short periods of imbibition at or below 12 to 14 C reduce embryo germination and axi...

The main procyanidins, including dimeric B2 and B5, trimeric C1, tetrameric and pentameric procyanidins, were isolated from unroasted cocoa beans (Theobroma cacao L.) using various techniques of countercurrent chromatography, such as high-speed countercurrent chromatography (HSCCC), low-speed rotary countercurrent chromatography (LSRCCC) and spiral-coil LSRCCC. Furthermore, dimeric procyanidins...

Transients in water content are well-known to mobilize microorganisms that are retained in the vadose zone. However, there is no consensus on the relative importance of drainage and imbibition events on microorganism release. To overcome this limitation, we have systematically studied the release of Escherichia coli D21g during cycles of drainage and imbibition under various solution chemistry ...

Directional imbibition of oils (hexadecane, tetradecane, and dodecane) and water is demonstrated on a chemically patterned silicon micropillar array. Four different directional imbibition types are shown: unidirectional, two types of bidirectional and tridirectional imbibition. The surfaces consist of a silicon micropillar array with an overlaid surface chemistry pattern. This configuration lea...

Imbibition during the first few hours is crucial for the success of seed germination process. The effect of water deficit after 2 and 8 hours (h) of imbibition of seeds of durum wheat was studied in terms of reserve mobilization, total sugars and proteins at 24, 48 and 72 h post treatment. Imbibition for 2 and 8 h was not enough to support normal mobilization of seed reserves and solubilization...

Countercurrent systems have evolved in a variety of biological systems that allow transfer of heat, gases, and solutes. For example, in the renal medulla, the countercurrent arrangement of vascular and tubular elements facilitates the trapping of urea and other solutes in the inner medulla, which in turn enables the formation of concentrated urine. Arteries and veins in the cortex are also arra...

A physical model was used in a laboratory exercise to teach students about countercurrent exchange mechanisms. Countercurrent exchange is the transport of heat or chemicals between fluids moving in opposite directions separated by a permeable barrier (such as blood within adjacent blood vessels flowing in opposite directions). Greater exchange of heat or chemicals between the fluids occurs when...

[1] Electric field bursts were passively observed when a nonwetting fluid displaced a wetting fluid in a porous material (drainage) as well as during imbibition experiments. A sandbox experiment was conducted to study these electrical disturbances using a network of very sensitive nonpolarizing electrodes located at the top surface of the tank. Drainage exhibited many more electrical bursts, wi...