Abstract: Described embodiments generally relate to a computer-implemented method for modelling a subsurface formation. The method comprises receiving measurement data related to the subsurface formation, the measurement data comprising a plurality of data points; determining at least one rock physics model, each rock physics model relating to a rock type; assigning each data point of the measurement data to at least one initial rock class membership; fitting each determined rock physics model of the at least one rock physics model to the data points of the measurement data to produce at least one fitted rock physics model; reassigning each data point to at least one rock class based on the fitted rock physics models; determining whether a convergence criterion has been met; and responsive to the convergence criterion not being met, repeating the fitting and reassigning steps.

Abstract: A process for the production of pyrolytic carbon comprising the steps of: (A) depositing pyrolytic carbon on a substrate, and (B) controlling the structure of the deposited pyrolytic carbon through use of a Volmer-Weber island growth model.

Abstract: A method to stereospecifically prepare a steroidal sapogenin or a derivative thereof by reducing a 3-keto,5?-H steroidal sapogenin with a hindered organoborane or an organo-aluminium hydride. A 3?-hydroxy,5?-H steroidal sapogenin or derivative thereof may be prepared by reducing the 3-keto,5?-H steroidal sapogenin using as reducing agent a relatively highly hindered organoborane reagent or by SN 2 inversion of a 3?-hydroxy,5?-H steroidal sapogenin or derivative thereof. The organo-aluminium hydride may be used to prepare a 3?,5?-H steroidal sapogenin or derivative thereof. The invention provides a convenient route to useful steroidal sapogenins such as sarsasapogenin, episarsasapogenin, smilagenin, epismilagenin and esters thereof, from readily available or easily preparable starting materials (e.g. diosgenone, preparable from diosgenin).

Abstract: A method for selectively separating desirable steroidal glycosides from undesirable components present in plant material of the Asclepiadaceae family containing the same. The method comprises contacting the plant material or material derived therefrom (herein: “the material”) with liquid or supercritical carbon dioxide under conditions whereby the desirable steroidal glycosides dissolve in the liquid or supercritical carbon dioxide in preference to the undesirable components, and subsequently recovering the desirable steroidal glycosides from the carbon dioxide solution.

Abstract: Compounds of general formula I: wherein: R1 and R2 are, independently of each other, selected from hydrogen, optionally substituted C1-10alkyl, optionally substituted —CO—(C1-10alkyl), optionally substituted C3-10cycloalkyl, optionally substituted —CO—(C3-10cycloalkyl), optionally substituted C2-10alkenyl, optionally substituted —CO—(C2-10alkenyl), optionally substituted aryl, and optionally substituted —CO-aryl, or R1 and R2 together represent an optionally substituted saturated or unsaturated C1-10alkylidene group, or an optionally substituted saturated or unsaturated C3-10cycloalkylidene group, or R1 and R2 together with the carbon atom to which they are attached represent an optionally substituted saturated or unsaturated organic ring containing 3, 4, 5, 6, 7 or 8 ring carbon atoms and optionally 1, 2 or 3 ring heteroatoms selected from O, N and S; R3, which may be the same as, or different from, either of R1 and R2, is selected from optionally substituted C1-10alkyl, optionally substituted C3-10cycl

Abstract: A method is disclosed for determining improved estimates of properties of a model, on the basis of estimated prior constraints, by running a mathematical inversion several times using the output posterior estimate of the previous inversion, or any of the previous inversions to provide an input for the next inversion. This iterative inversion may be repeated until the prior and posterior estimates converge to within a given threshold. The method may be applied to seismic data, using a seismic inversion, in order to improve the prediction of the viability of potential petroleum reservoirs by determining improved estimates of volumetric properties of a subsurface region.