Single reporter for targeted multimodal in vivo imaging

We have developed a multifaceted, highly specific reporter for multimodal in vivo imaging and applied it for detection of brain tumors. A metabolically biotinylated, membrane-bound form of Gaussia luciferase was synthesized, termed mbGluc-biotin. We engineered glioma cells to express this reporter and showed that brain tumor formation can be temporally imaged by bioluminescence following systemic administration of coelenterazine. Brain tumors expressing this reporter had high sensitivity for detection by magnetic resonance and fluorescence tomographic imaging upon injection of streptavidin conjugated to magnetic nanoparticles or fluorophore, respectively. Moreover, single photon emission computed tomography showed enhanced imaging of these tumors upon injection with streptavidin complexed to (111)In-DTPA-biotin. This work shows for the first time a single small reporter (～40 kDa) which can be monitored with most available molecular imaging modalities and can be extended for single cell imaging using intravital microscopy, allowing real-time tracking of any cell expressing it in vivo.     

Antimony-antimony bond formation by reductive elimination from a hafnium bis(stibido) complex

The bis(stibido) complex CpCp*Hf(SbMes2)2 (2) was prepared and structurally characterized. Complex 2 reacts with 2 equiv of xylylisocyanide to give the bis-insertion product CpCp*Hf[C(SbMes2)=N(2,6-MeC6H3)]2 (4). The reaction of 2 with oxidants (I2 and O2) or donors (carbon monoxide and diphenylacetylene) or thermolysis promotes the reductive elimination of Sb2Mes4.     

A new coumarin and triterpenes from Malaysian Micromelum minutum

A new coumarin, 8,4'-dihydroxy-3',4'-dihydrocapnolactone-2',3'-diol (1) and two known triterpenes, 5(6)-gluten-3-one (2) and 5(6)-gluten-3alpha-ol (3) were isolated from the leaves of Micromelum minutum (Rutaceae) collected from Sepilok, Sabah, Malaysia and their structures were characterized by spectroscopic methods.     

Vinyl chloride–propylene copolymerization

Because of the allylic nature of propylene, the vinyl chloride–propylene system exhibits polymerization behavior markedly different from that of vinyl chloride, even at relatively low propylene concentrations. Propylene acts as a degradative chain-transfer agent, and as a result, both the polymerization rate and the molecular weight of the resultant copolymers are lower than those of the homopolymer, decreasing with increasing propylene content. Even at propylene concentrations as low as 10% the rate of polymerization is proportional to the initiation rate, indicating kinetic control by the propylene. The reactivity ratios of these monomers given by Cain were verified. The reciprocal intrinsic viscosity of the copolymer was found to be linearly related to the monomer feed composition.     

Inertia effects in rheometrical flow systems Part 3: Some energy considerations with respect to the flow field in the balance rheometer

Summary Following up a previous paper by one of the presents authors on the flow field in the balance rheometer, inertia effects being included, in this paper some energy considerations with respect to this flow field are presented. It is shown that in a frame rotating with the same angular velocity as the hemispheres the power supplied by these hemispheres equals the rate of energy dissipation in the sample, i.e. in this coordinate system there is no stress power paradox. Further it is shown that the elastic couple for a Newtonian liquid, appearing in the calculations, stems from the extra kinetic energy caused by the deviation of the actual flow field from the flow field that appears when inertia effects are ignored.

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Zusammenfassung Als Fortsetzung des früheren Beitrages eines der hier genannten Autoren über das Strömungsfeld in einem Képès-Rheometer unter Berücksichtigung der Flüssigkeitsträgheit werden in diesem Beitrag einige Energiebetrachtungen angestellt. Es wird gezeigt, daß in einem Koordinatensystem, das mit gleicher Winkelgeschwindigkeit wie die Halbkugeln rotiert, die durch diese Halbkugeln zugeführte Leistung der in der Probe dissipierten Leistung gleich ist, d. h. daß in diesem Koordinatensystem das sogenannte Spannungsenergieparadox nicht vorliegt. Es wird weiter gezeigt, daß das bei einer newtonschen Flüssigkeit auftretende elastische Drehmoment seinen Ursprung in der zusätzlichen kinetischen Energie hat, die der Abweichung des tatsächlichen Strömungsfeldes von dem unter Vernachlässigung der Flüssigkeitsträgheit berechneten Strömungsfeld entspricht.

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a distance between rotation axes of orthogonal rheometer - b, c positive numbers (see eq. [29]) - f _n (z) j _n (z),y _n (z),h _n ⁽¹⁾ (z) orh _n ⁽²⁾ (z) - h distance between discs of orthogonal rheometer - h _n ⁽¹⁾ (z) =j _n (z) +iy _n (z) spherical Bessel functions of the third kind and ordern - h _n ⁽²⁾ (z) =j _n (z) –iy _n (z) spherical Bessel functions of the third kind and ordern - i - j _n (z) spherical Bessel function of the first kind and ordern - k – (/2)^1/2 - n integer - p ₁ j ₁(r ₂)y ₁(r ₁) –j ₁(r ₁)y ₁(r ₂) - q ₁ - r spherical polar coordinate - r ₁(r ₂) radius of inner (outer) hemisphere - s ₁ - t time - u _r ,u ,u physical components of displacement - x, z variables - x, y, z cartesian coordinates in eq. [1] - y _n (z) spherical Bessel function of the second kind and ordern - E _kin kinetic energy - E _s stored energy - F force - F _n (z) J _n (z),Y _n (z),H _n ⁽¹⁾ (z) orH _n ⁽²⁾ (z) - G ^* =G + iG complex shear modulus - H _n ⁽¹⁾ (z) =J _n (z) +iY _n (z) Bessel functions of the third kind and ordern - H _n ⁽²⁾ (z) =J _n (z) –iY _n (z) Bessel functions of the third kind and ordern - Im imaginary part of - J _n (z) Bessel function of the first kind and ordern - N - P energy supplied to the sample during one cycle - Re real part of - S strain - U - W energy dissipated in the sample during one cycle - Y _n Bessel function of the second kind and ordern - (/G ^*)^1/2-complex shear wave factor - /(r ₁ +r ₂) - loss angle - angle between rotation axes of balance rheometer - viscosity - spherical polar coordinate - order of cylinder function (see eq. [24]) - linear combination of spherical Bessel functions of first, second, and third kind, in which the coefficients are independent of the argument and the order - µ, v constants (see eq. [24]) - see - density - shear stress - spherical polar coordinate - cylinder functions - angular velocity With 3 figures     

Design of an automated particle sizing apparatus

The ability of fast transient electric birefringence data to measure directly the size distribution for non-spherical particles in the micron and sub-micron range has been appreciated for a number of years. As no commercial system exists, this paper gives practical details of a compact, safe and accurate apparatus to enable laboratory analysts to design, construct and use a system of their own. The method is fast, and the size data are accurate to within ten percentage points.     

Silicon–Nitrogen Bond Formation via Heterodehydrocoupling and Catalytic N-Silylation

Silicon–nitrogen bond formation is an important subfield in main group chemistry, and catalysis is an attractive route for efficient, selective formation of these bonds. Indeed, heterodehydrocoupling and N-silylation offer facile methods for the synthesis of small molecules through the coupling of primary, secondary, and tertiary silanes with N-containing substrates such as amines, carbazoles, indoles, and pyrroles. However, the reactivity of these catalytic systems is far from uniform, and critical issues are often encountered with product selectivity, conversions, substrate scope, catalyst activation, and in some instances, competing side reactions. Herein, a catalogue of catalysts and their reactivity for Si−N heterodehydrocoupling and N-silylation are reported.     

Bisresorcinol Derivatives from Grevillea glauca

Seven new and three known bisresorcinols, grevirobstol A (=5,5′‐((6Z,9Z)‐hexadeca‐6,9‐diene‐1,16‐diyl)bisresorcinol; 8 ), 5,5′‐[(8Z)‐hexadec‐8‐ene‐1,16‐diyl]bisresorcinol ( 9 ), and 2‐methyl‐5,5′‐[8Z)‐hexadec‐8‐ene‐1,16‐diyl]bisresorcinol ( 10 ) were isolated from the stems of Grevillea glauca. The new compounds were identified on the basis of spectroscopic data as (Z)‐6,7‐didehydroglaucone A ( 1 ), glaucones A and B ( 2 and 3 , resp.), 2‐(3‐hydroxyisopentyl)bisnorstriatol ( 4 ), 2‐(3‐methylbut‐2‐en‐1‐yl)bisnorstriatol ( 5 ), 2′‐methylgrebustol A ( 6 ), and glaucane ( 7 ).