Fourier-transform infrared spectroscopy discriminates a spectral signature of endometriosis independent of inter-individual variation

Endometriosis is the growth of endometrial tissue outside of the uterine cavity. Its aetiology remains obscure, and it is difficult to diagnose ranging from asymptomatic to debilitating disease. Mid-infrared (IR) spectroscopy has become recognised as a potential clinical diagnostic tool. Biomolecules absorb mid-IR (4000 cm(-1) to 400 cm(-1)) and from this, a biochemical-cell fingerprint in the form of an absorbance spectrum can be derived. We set out to determine if IR spectroscopy could be used to identify underlying biochemical differences between endometrial tissues growing outside of the uterus (ectopic) from endometrial tissue of the uterus (eutopic). For comparative purposes, endometrial tissues from endometriosis-free women were also obtained (benign eutopic). Attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy or transmission FTIR microspectroscopy was employed for spectral acquisition. Principal component analysis (PCA)-linear discriminant analysis (LDA) was used for chemometric analysis. A clear segregation was exhibited between the three categories independent of inter-individual confounding differences. Importantly, there was a marked difference between eutopic endometrial tissue from patients with or without endometriosis. This indicates that IR spectroscopy coupled with multivariate analysis (e.g., PCA-LDA) may provide a non-invasive diagnostic tool for endometriosis. By analysing the underlying biochemistry of these endometrial tissues, this approach may facilitate a better understanding of this pathology.     

Stability of Parallel Fluid Loaded Plates: A Nonlocal Approach

We consider the motion of a collection of fluid loaded elastic plates, situated horizontally in an infinitely long channel. We use a new, unified approach to boundary value problems, introduced by A.S. Fokas in the late 1990s, and show the problem is equivalent to a system of one‐parameter integral equations. We give a detailed study of the linear problem, providing explicit solutions and well‐posedness results in terms of standard Sobolev spaces. We show that the associated Cauchy problem is completely determined by a matrix, which depends solely on the mean separation of the plates and the horizontal velocity of each of the driving fluids. This matrix corresponds to the infinitesimal generator of the C₀ ‐semigroup for the evolution equations in Fourier space. By analyzing the properties of this matrix, we classify necessary and sufficient conditions for which the problem is asymptotically stable.     

Two-phase stratified flow splitting at a T-jun

The objective of this study is to investigate, experimentally and theoretically, two-phase splitting under stratified wavy flow conditions at a regular horizontal T -junction with an inclined branch arm.

Experimental data have been acquired with the side arm at horizontal conditions, downward inclination angles of −5, −10, −25, −40 and −60°, and upward inclinations of 1, 5, 10, 20, and 35° from the horizontal. The data reveal that gravity forces have a significant effect on the flow splitting. For downward inclination of the side arm more liquid is diverted into the branch arm, as compared to the case in which the side arm was horizontal. All the liquid was found to be diverted into the branch arm when the branch arm inclination was increased to −60°. For upward inclination angles a significant amount of the inlet gas has to be diverted into the side arm in order to get any liquid to flow into that arm. However, once liquid has started flowing, not much more additional gas has to be diverted into the side arm to get all of the liquid to flow into the branch. At 35° almost all the gas has to be diverted for any liquid flow into the branch.

A mechanistic model has been developed for the prediction of the splitting phenomenon for both the horizontal and the downward orientations of the side arm. The model is based on the momentum equations applied for the separation streamlines of the gas phase and the liquid phase. Very good agreement is observed between the prediction of the model and the data acquired for all the cases.     

Application of phosphonate and thiophosphate analogues of nucleotides to studies of some enzyme reactions

The enzymatic cleavage of a scissile P O bond can be blocked by recourse to phosphonate analogues of biological phosphate esters. α-Fluorophosphonates have an enhanced electronegativity at the bridging carbon, which, in many cases, makes them superior to simple methylene phosphonates for the study of enzyme reactions. Thus, the β,γ-difluoro-methylene analogue of ATP is a good substrate for the interferon-induced (2→5)A_n synthetase, which converts it into a (2→5)A₄ species having a 5′-β,γ-difluoromethylenetriphosphate. This binds strongly to RNase L but does not activate it. The unsymmetrical Ap₄Aases from Artemia and Lupin are strongly inhibited by P^1,P⁴-dithiophosphate analogues of diadenosyl-5′,5‴-P¹,P⁴-tetraphosphate although nonregiospecific cleavage of certain P²,P³-methylene analogues can be observed. Some of these analogues are remarkably effective inhibitors of platelet aggregation and are effective inhibitors in vivo of arterial blood-clotting in rabbits. Separation of all diastereoisomers of P¹,P⁴-dithiophosphate analogues of Ap₄A is achieved cleanly using reverse-phase hplc chromatography and this provides direct access to β,γ-CHF-bridged analogues of ATP with resolved stereochemistry at the CHF center. Lastly, growing cells of Dictyostelium discoideum not only tolerate a range of substituted methylene bisphosphonates in their growth medium but actually incorporate them into nucleotide analogues of ATP and Ap₄A.