Photochemistry of Bacteriochlorophylls in Human Blood Plasma: 1. Pigment Stability and Light-induced Modifications of Lipoproteins

Transmetalated derivatives of bacteriochlorophyll are promising sensitizers in photodynamic therapy. Protocols using short delay times between injection and irradiation cause interest in the photochemistry of these pigments in the blood. Using near-infrared irradiation where these pigments absorb strongly, we have studied the photochemistry of Zn- and Pd-bacteriopheophorbide (WST09), and of the highly polar taurinated Pd-derivative, WST11, in isolated fractions of human blood plasma. The stability of all pigments is increased in blood plasma, compared with monomeric solutions. Pd-bacteriopheophorbide is much more stable than the other two derivatives. It also has a higher capacity for inducing reactive oxygen species, yet the consumption of oxygen is comparable. There is furthermore evidence for photobleaching under anoxic conditions. The generation of hydroperoxides (ROOH) is faster with Pd- than with Zn-complexes; the formation of endoperoxides (ROOR′), measured as thiobarbituric acid reactive substances, is comparable with the two central metals. Formation of both ROOH and ROOR′ is increased in low-density lipoproteins (LDL) compared with high-density lipoproteins (HDL), which is probably related to the higher concentration of target molecules in the former. In HDL, extensive cross-linking is induced among the apolipoproteins; judged from the electrophoretic mobility of LDL and HDL particles, there is also a gross structural change. Photosensitized cross-linking is much less pronounced with high-density proteins.     

Collars and partitions of hyperbolic cone-surfaces

For compact Riemann surfaces, the collar theorem and Bers’ partition theorem are major tools for working with simple closed geodesics. The main goal of this article is to prove similar theorems for hyperbolic cone-surfaces. Hyperbolic two-dimensional orbifolds are a particular case of such surfaces. We consider all cone angles to be strictly less than π to be able to consider partitions. Emily B. Dryden—partially supported by the US National Science Foundation grant DMS-0306752. Hugo Parlier—supported by the Swiss National Science Foundation grants 21-57251.99 and 20-68181.02.     

Continuous families of Hölder functions that are not of bounded variation

This paper deals with three classes of functions of great importance in analysis and its applications. We construct a family of Hölder functions in the closed unit interval having two continuous parameters. Those functions are not of bounded variation for any pair of values of the Hölder constant and exponent. The construction depends on a change of variables given by a Lipschitz function with constant equal to 1. Several questions related to the concepts of genericity, surjectivity and deformability are posed at the end.     

Un processus effectif de détermination des systoles pour les surfaces hyperboliques

We give an effective process to discribe explicitly the systols of an hyperbolic surface depending on his Fenchel-Nielsen coordinates.      

A comparison of depletion versus equalization for reducing high-abundance proteins in human serum

In this work three methods to diminish the content of most highly abundant proteins in human serum have been studied and compared. Protein depletion with ACN or DTT and protein equalization with the ProteoMiner^? (PM) have been assessed by 1‐D gel electrophoresis and MS. After treatment 5, 18 and 9 major proteins within the 20 most abundant proteins in serum were identified for the ACN, DTT and PM methods, respectively. The ACN method was efficient for depleting high molecular weight proteins, over 75 KDa, resulting in 10±4% (n=3) of the total protein content remaining in the depleted serum. In addition, 75% of the proteins belonging to the group of the 20 most abundant proteins were not detected, making this depletion strategy a cheap alternative to expensive commercial tools regularly used for removing high abundance proteins from serum. The ACN extract was found rich in apolipoproteins. The dithithreitol method promotes the precipitation of proteins rich in disulfide bonds, mainly albumin, with 73±7% (n=3) of the total protein content remaining in the depleted serum, which was found rich in immunoglobulins. The PM method compresses the dynamic range of the serum proteins, rendering an extract containing 16±2% (n=3) of the total initial protein content. The extract was found to be rich in both apolipoproteins and immunoglobulins. As a general rule the DTT and PM methods provide a compression of the dynamic range of serum protein concentrations while the ACN method allows an effective depletion of the protein fraction above 72 KDa.     

Biosynthesis of iron and silver nanoparticles at room temperature using aqueous sorghum bran extracts

Iron and silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous sorghum extracts as both the reducing and capping agent. Silver ions were rapidly reduced by the aqueous sorghum bran extracts, leading to the formation of highly crystalline silver nanoparticles with an average diameter of 10 nm. The diffraction peaks were indexed to the face-centered cubic (fcc) phase of silver. The absorption spectra of colloidal silver nanoparticles showed a surface plasmon resonance (SPR) peak centered at a wavelength of 390 nm. Amorphous iron nanoparticles with an average diameter of 50 nm were formed instantaneously under ambient conditions. The reactivity of iron nanoparticles was tested by the H(2)O(2)-catalyzed degradation of bromothymol blue as a model organic contaminant.