Fluorescent small molecule probe to modulate and explore α2β1 integrin function

Collagen binding integrins are an important family of cell surface receptors that mediate bidirectionally signals between the interior of the cell and the extracellular matrix. The protein-protein interactions between cells and collagen are necessary for many physiological functions, but also promote diseases. For example, the interaction of α2β1 integrin and collagen has been shown to have an important role in thrombus formation and cancer spread. The fact that the discovery of small molecules that can block such protein-protein interactions is highly challenging has significantly hindered the discovery of pharmaceutical agents to treat these diseases. Here, we present a rationally designed novel fluorescent molecule that can be synthesized in just a few minutes from commercially available starting materials. This molecule blocks the protein-protein interaction between α2β1 integrin and collagen, and due to its fluorescent properties, it can be employed in wide variety of biological applications.     

Lab‐on‐a‐Chip Reactor Imaging with Unprecedented Chemical Resolution by Hadamard‐Encoded Remote Detection NMR

The development of microfluidic processes requires information‐rich detection methods. Here we introduce the concept of remote detection exchange NMR spectroscopy (RD‐EXSY), and show that, along with indirect spatial information extracted from time‐of‐flight data, it provides unique information about the active regions, reaction pathways, and intermediate products in a lab‐on‐a‐chip reactor. Furthermore, we demonstrate that direct spatial resolution can be added to RD‐EXSY efficiently by applying the principles of Hadamard spectroscopy.     

Intra-Channel Nonlinear Effect on Optical PPM Pulse Transmission

PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channel system.     

Intramolecular cyclization of chloral allyl hemiacetal under the action of the Fe(CO)5-DMF system

Chloral allyl hemiacetal undergoes cyclization in the presence of the Fe(CO)₅-DMF system to form 3,3,5-trichloro-2-hydroxytetrahydropyran rather than a butyrolactone derivative. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 750–752, April, 1999.     

Black Holes as Atoms

Stationary spacetimes containing a black hole have several properties akin to those of atoms. For instance, such spacetimes have only three classical degrees of freedom, or observables, which may be taken to be the mass, the angular momentum, and the electric charge of the hole. There are several arguments supporting a proposal originally made by Bekenstein that quantization of these classical degrees of freedom gives an equal spacing for the horizon area spectrum of black holes. We review some of these arguments and introduce a specific Hamiltonian quantum theory of black holes. Our Hamiltonian quantum theory gives, among other things, a discrete spectrum for the classical observables, and it produces an area spectrum which is closely related to Bekenstein's proposal. We also present a foamlike model of horizons of spacetime. In our model spacetime horizon consists of microscopic Schwarzschild black holes. Applying our Hamiltonian approach to this model we find that the entropy of any horizon is one quarter of its area.     

Virtual quark-quark scattering in the pseudoparticle background

We calculate off-shell four point functions of massless fermions in a pseudoparticle background. The results are exact to lowest order quantum fluctuations about the classical pseudoparticle field. Only pseudoparticle solutions of unit winding number contribute to the calculated correlation functions. The developed technique requires knowledge only of the zero frequency fermion solutions in the pseudoparticle potential.     

Characterization of the alnumycin gene cluster reveals unusual gene products for pyran ring formation and dioxan biosynthesis

Alnumycin is closely related to the benzoisochromanequinone (BIQ) polyketides such as actinorhodin. Exceptional structural features include differences in aglycone tailoring that result in the unique alnumycin chromophore and the existence of an unusual 4-hydroxymethyl-5-hydroxy-1,3-dioxan moiety. Cloning and sequencing of the alnumycin gene cluster from Streptomyces sp. CM020 revealed expected biosynthesis genes for polyketide assembly, but several genes encoding subsequent tailoring enzymes were highly atypical. Heterologous expression studies confirmed that all of the genes required for alnumycin biosynthesis resided within the sequenced clone. Inactivation of genes aln4 and aln5 showed that the mechanism of pyran ring formation differs from actinorhodin and granaticin pathways. Further inactivation studies identified two genes, alnA and alnB, involved in the synthesis and attachment of the dioxan moiety, and resulted in the production of the polyketide prealnumycin.     

Structural studies of seven homoisoflavonoids, six thiohomoisoflavonoids, and four structurally related compounds

¹H and ¹³C NMR chemical shifts have been determined and assigned based on PFG ¹H, ¹³C HMQC, and HMBC experiments for 3-(4′-X-benzyl)-4-chromenones (Ia, X = CN and Ib, X = NO₂), 3-(4′-X-benzyl)-4-thiochromenones (IIa, X = Cl and IIb, X = Br), (E)-3-(4′-X-benzylidene)-4-chromanones (IIIa–IIIe, X = OCH₃, CH₃, Cl, N(CH₃)₂, Br), (Z)-3-(4′-X-benzylidene)4-thiochromanones (IVa–IVd, X = Cl, Br, F, OCH₃), 2-benzyl-1,2,3,4-tetrahydro-1-naphthol (V), 2-benzyl- and (E)-2-benzylidene-1-tetralones (VI and VII), and (E)-2-benzylidene-1-benzosuberol (VIII). The crystal structures have been determined for the following seven compounds: derivatives of 4-chromanones (IIIa–IIId), 1-tetrahydronaphtol (V), and 1-tetralones (VI and VII). The molecular features and intermolecular interactions in crystal state have been discussed.