Two-phase flow in a horizontal equal-sided impacting tee junction

Pressure-drop and phase-distribution data were generated for air–water flows in a horizontal impacting tee junction. All three sides of the junction (37.8-mm i.d.) were oriented horizontally. The data correspond to a junction pressure of 1.5 bar (abs), ambient temperature, inlet flow regimes of wavy, stratified, and annular, and a wide range of mass splits at the junction. Most of the range for the phase-distribution data corresponds to conditions that were untested in previous investigations. In general, it was found that the phases did not distribute themselves evenly between the two outlets unless the mass split is equal. There is a serious lack of data in the literature on the two-phase pressure drop in impacting tee junctions and therefore, the present data add substantially to the existing data. A mechanistic model capable of predicting the phase distribution and pressure drop was developed and shown to be in general good agreement with the present data and others from the literature.     

Correlation of p16(INK4A) expression and HPV copy number with cellular FTIR spectroscopic signatures of cervical cancer cells

Cervical cancer, a potentially preventable disease, has its main aetiology in infection by high risk human papillomavirus (HR-HPV). Approaches to improving cervical cancer screening and diagnostic methodologies include molecular biological analysis, targeting of biomarker proteins, but also exploration and implementation of new techniques such as vibrational spectroscopy. This study correlates the biomarker protein p16(INK4A) expression levels dependent on HPV copy number with the infrared absorption spectral signatures of the cervical cancer cell lines, HPV negative C33A, HPV-16 positive SiHa and CaSki and HPV-18 positive HeLa. Confocal fluorescence microscopy demonstrated that p16(INK4A) is expressed in all investigated cell lines in both nuclear and cytoplasmic regions, although predominantly in the cytoplasm. Flow cytometry was used to quantify the p16(INK4A) expression levels and demonstrated a correlation, albeit nonlinear, between the reported number of integrated HPV copies and p16(INK4A) expression levels. CaSki cells were found to have the highest level of expression, HeLa intermediate levels, and SiHa and C33A the lowest levels. FTIR spectra revealed differences in nucleic acid, lipid and protein signatures between the cell lines with varying HPV copy number. Peak intensities exhibited increasing tendency in nucleic acid levels and decreasing tendency in lipid levels with increasing HPV copy number, and although they were found to be nonlinearly correlated with the HPV copy number, their dependence on p16(INK4A) levels was found to be close to linear. Principal Component Analysis (PCA) of the infrared absorption spectra revealed differences between nuclear and cytoplasmic spectroscopic signatures for all cell lines, and furthermore clearly differentiated the groups of spectra representing each cell line. Finally, Partial Least Squares (PLS) analysis was employed to construct a model which can predict the p16(INK4A) expression level based on a spectral fingerprint of a cell line, demonstrating the diagnostic potential of spectroscopic techniques.     

Targeting choroid plexus epithelia and ventricular ependyma for drug delivery to the central nervous system

Background  

Because the choroid plexus (CP) is uniquely suited to control the composition of cerebrospinal fluid (CSF), there may be therapeutic benefits to increasing the levels of biologically active proteins in CSF to modulate central nervous system (CNS) functions. To this end, we sought to identify peptides capable of ligand-mediated targeting to CP epithelial cells reasoning that they could be exploited to deliver drugs, biotherapeutics and genes to the CNS.     

Absolutely Continuous Spectra of Quantum Tree Graphs with Weak Disorder

We consider the Laplacian on a rooted metric tree graph with branching number K≥2 and random edge lengths given by independent and identically distributed bounded variables. Our main result is the stability of the absolutely continuous spectrum for weak disorder. A useful tool in the discussion is a function which expresses a directional transmission amplitude to infinity and forms a generalization of the Weyl-Titchmarsh function to trees. The proof of the main result rests on upper bounds on the range of fluctuations of this quantity in the limit of weak disorder.     

Synthesis of pallescensin-E : Use of crown ether in the Wadsworth procedure for olefin formation

The furanosesquiterpene, pallescensin-E has been prepared by a route involving reaction of a dimethyl 3-furylmethyl phosphonate anion with 2,3-dimethylbenzaldehyde in the presence of 15-crown-5; this reaction has been shown to have general applicability.     

Marine natural products—XV : Polyhalogenated cyclic monoterpenes from the red alga plocamium cartilagineum of antarctica

Examination of the red alga Plocamium cartilagineum (L.) Dixon collected along the Antarctic Peninsula yielded several new cyclic halogenated monoterpenes. The structures of a 2,4-dichloro-trans-1-chloro-vinyl-1-methyl-5-methylene-cyclohexane, a 2-chloro-4-bromo-trans-1-chlorovinyl-1-methyl-5-methylene-cyclohexane, a 2-chloro-trans-1-chlorovinyl-1-methyl-5-chloromethyl-4-cyclohexene, and a 2,5-dichloro-4-bromo-trans-1-chlorovinyl-1-methyl-5-bromomethyl-cyclohexane are described. The structures were determined by spectroscopic methods and chemically related to the halogenated monoterpene violacene.     

Copper thioether chemistry: The synthesis and single crystal X-ray structures of [Cu2([18]aneS6)(NCMe)2](ClO4)2 and [Cu([9]aneS3)(AsPPh3)](ClO4)

Reaction of [18]aneS₆ with two molar equivalents of [Cu(NCMe)₄](ClO₄) in CH₂Cl₂-MeCN affords the binuclear copper(I) complex [Cu₂([18]aneS₆)(NCMe)₂](ClO₄)₂. The single crystal X-ray structure of the complex shows a centrosymmetric cation with two tetrahedral copper(I) centres each coordinated to three thioether S-donors of [18]aneS₆,Cu---S(1) = 2.3200(15), Cu---S(4) = 2.3415(16), Cu---S(7) = 2.3250(15) Å, and to one MeCN molecule, Cu---N(1) = 1.939(5) Å, to give an overall NS₃-donation at the metal centres. Additionally, S(7′) shows a long-range interaction, Cu …S(7′) = 3.318(2) Å thus distorting the coordination geometry of the metal ion towards trigonal bipyramidal. The metal-metal separation of 4.428(2) Å suggests that there is no significant interaction between the copper centres of the dimer. Reaction of [9]aneS₃ with one molar equivalent of [Cu(NCMe)₄](ClO₄) in refluxing MeCN in the presence of ligands, L, affords the adducts [Cu([9]aneS₃)L]⁺ (L = PPh₃, AsPh₃). The single crystal X-ray structure of the complex [Cu([9]aneS₃)(AsPh₃)](ClO₄) shows tetrahedral AsS₃ coordination at copper(I) with [9]aneS₃ bound facially to the metal centre, Cu---S = 2.303(6), Cu---As = 2.322(4) Å.     

Entanglement Dynamics of Disordered Quantum XY Chains

We consider the dynamics of the quantum XY chain with disorder under the general assumption that the expectation of the eigenfunction correlator of the associated one-particle Hamiltonian satisfies a decay estimate typical of Anderson localization. We show that, starting from a broad class of product initial states, entanglement remains bounded for all times. For the XX chain, we also derive bounds on the particle transport which, in particular, show that the density profile of initial states that consist of fully occupied and empty intervals only have significant dynamics near the edges of those intervals, uniformly for all times.     

Thioesterase-like role for fungal PKS-NRPS hybrid reductive domains

Fungal reduced polyketides possess diverse structures exploring a broad region of chemical space despite their synthesis by very similar enzymes. Many fungal polyketides are capped by diverse amino acid-derived five-membered rings, the tetramic acids and related pyrrolidine-2-ones. The known tetramic acid synthetase enzymes in fungi contain C-terminal reductive (R) domains that were proposed to release reduced pyrrolidine-2-one intermediates en route to the tetramic acids. To determine the enzymatic basis of pyrrolidine-2-one diversity, we overexpressed equisetin synthetase (EqiS) R domains and analyzed their reactivity with synthetic substrate analogs. We show that the EqiS R domain does not perform a reducing function and does not bind reducing cofactors. Instead, the EqiS R catalyzes a Dieckmann condensation, with an estimated kcat approximately 15 s(-1). This role differs from the redox reactions normally catalyzed by short chain dehydrogenase/reductase superfamily enzymes.     

Attenuated total reflection infrared studies of oleate and trioctylphosphine oxide ligand adsorption and exchange reactions on CdS quantum dot films

Ligand exchange reactions at the surface of oleate- and trioctylphosphine oxide (TOPO)-capped CdS quantum dots have been studied with attenuated total reflection infrared (ATR-IR) spectroscopy, using thin films deposited from organic solvent suspensions. The oleate and trioctylphosphine capping ligands were found to form highly ordered and densely packed monolayers on the CdS surface. Adsorbed oleate is coordinated to CdS in a chelating bidentate manner through the carboxylate functional group, while adsorbed trioctylphosphine oxide is coordinated though the P=O functional group and appears to have numerous adsorption environments on the CdS surface. Exposure of such films to aqueous solution was found to cause partial delamination of the films from the ATR prism interface which was reversible upon redrying. Ligand exchange reactions on the oleate- and trioctylphosphine-capped CdS films were studied in situ at room temperature by allowing the films to be exposed to dilute aqueous solutions of thiol-containing ligands. Oleate and trioctylphosphine oxide are both strongly adsorbed to the CdS surface, and ligand exchange with monothiol-containing ligands has been found to be highly dependent upon experimental conditions, in particular pH, where exchange is only observed at solution pH where the exchanging ligand is uncharged. This is attributed to the inability of a charged ligand to penetrate the hydrophobic polymethylene layer on the CdS surface.