Zinc-phosphate nanoparticles with reversibly attached TNF-α analogs: an interesting concept for potential use in active immunotherapy

The authors’ intention was to prepare nanometer-sized zinc-phosphate nanoparticles that would be capable of binding histidine-rich TNF-α analogs onto their surface via a coordinative bond. Zinc-phosphate nanoparticles with a size of around 60 nm were prepared by a wet precipitation method and characterized using SEM, EDX, XRD, and DLS. First, BSA was bound as a testing protein, afterward two TNF-α analogs with decreased activity were bound to the described nanoparticles. The efficiency of binding and the existence of coordinative bond were confirmed with SDS-PAGE analysis. During binding, particle storage, and release experiments, the prepared TNF-α analogs retained their biological activity—hence the epitopes necessary for formation of antibodies stayed intact. The particle size did not change within a period of 2 weeks. No significant agglomeration was observed, the particles could be quickly dispersed in ultrasound. The present nanoparticles and the general approach of coordinative binding are widely applicable for natural and engineered histidine-rich proteins. The nanoparticles bearing appropriate TNF-α analogs could also be potentially used for active immunotherapy to tackle the chronic inflammatory diseases associated with pathogenically elevated levels of TNF-α.     

Electrons ejected in resonant Raman scattering of X-rays on krypton

In the resonant Raman scattering of x-rays on krypton gas the ejected electrons were investigated by a proportional counter spectrometer. The cross sections for the process were determined for three energies of the incident photons (181 eV, 89 eV, and 33 eV below theK edge). The results agree with the theoretical predictions, thus independently confirming the theory that has so far only been tested by scattered photon data. From the cross sections the width of theK-shell excited state of krypton is extracted asΓ _K =(2.75±0.10) eV.     

TheK-shell fluorescence yield of germanium

TheK-shell fluorescence yield of germanium has been determined asω _K=0.570±0.003 by the modified proportional counter technique using a special wall-less proportional counter filled with methane and small admixture of germanium hydride GeH₄. The required ratio of the total photoabsorption to the absorption in theK-shell has been obtained from the separate study of the energy dependence of the X-ray absorption in germanium.     

The determination of theK-shell fluorescence yield of xenon by use of the proportional counter method

The wall-less proportional counter filled with propane with a small admixture of xenon was used as a spectrometer of electrons emitted by xenon atoms when photoelectrically excited by americium-241γ-rays and erbiumKα rays. TheK-shell fluorescence yield of xenon as extracted from spectra ammounts toω _k=0.889(1±0.01).     

Gradient chromatofocusing-mass spectrometry: A new technique in protein analysis

A new analytical technique, gradient chromatofocusing-mass spectrometry (gCF-MS), was developed employing ion-exchange high-performance liquid chromatography (HPLC) interfaced to an electrospray-quadrupole mass spectrometer in the determination of proteins. There have been few reports, if any, of a HPLC-MS technique for proteins in which the ion-exchange column is directly interfaced to the mass spectrometer. The employment of a linear pH gradient elution scheme directly interfaced to mass spectrometry is also unique in the present work. The technique was demonstrated by the separation of six proteins (carbonic anhydrase II, enolase, beta-lactoglobulin A, lactoglobulin B, soybean trypsin inhibitor, and amyloglucosidase) employing a descending linear pH gradient from pH 9 to 2.6 on a 50 mm x 2.1 mm DEAE HPLC column using volatile buffer components. A signal enhancement solution consisting of 8% formic acid in acetonitrile was pumped post-column and was mixed 1:1 with column effluent and then directed on-line into the mass spectrometer. Molecular masses of the proteins were determined within +/-0.010% to 0.033% (+/-100 to 330 ppm) with peak height total ion current detection limits of 4 to 78 pmol of injected amounts (S/N = 3). This technique is applicable to the analysis of proteins and other charged molecules.     

A mass spectral investigation of derivatives of kanamycin A

The high and low resolution mass spectra of the N-acetyl-N,O-methyl and N-acetyl-O-trimethylsilyl derivatives of kanamycin A have been determined and interpreted, along with those of deuterated analogs under conditions of electron impact. In addition, the chemical ionization mass spectrum of the N-acetyl-N,O-methyl derivative is presented. The use of these spectra for recognizing structural features, such as the sequence of the sugar units, is discussed. The characteristics of the two types of derivatives are compared. The value of the chemical ionization spectrum and the complementary nature of the data obtained from it are emphasized.     

How ions affect the structure of water

We model ion solvation in water. We use the MB model of water, a simple two-dimensional statistical mechanical model in which waters are represented as Lennard-Jones disks having Gaussian hydrogen-bonding arms. We introduce a charge dipole into MB waters. We perform (NPT) Monte Carlo simulations to explore how water molecules are organized around ions and around nonpolar solutes in salt solutions. The model gives good qualitative agreement with experiments, including Jones-Dole viscosity B coefficients, Samoilov and Hirata ion hydration activation energies, ion solvation thermodynamics, and Setschenow coefficients for Hofmeister series ions, which describe the salt concentration dependence of the solubilities of hydrophobic solutes. The two main ideas captured here are (1) that charge densities govern the interactions of ions with water, and (2) that a balance of forces determines water structure: electrostatics (water's dipole interacting with ions) and hydrogen bonding (water interacting with neighboring waters). Small ions (kosmotropes) have high charge densities so they cause strong electrostatic ordering of nearby waters, breaking hydrogen bonds. In contrast, large ions (chaotropes) have low charge densities, and surrounding water molecules are largely hydrogen bonded.     

Four algorithms to solve symmetric multi-type non-negative matrix tri-factorization problem

Journal of Global Optimization - In this paper, we consider the symmetric multi-type non-negative matrix tri-factorization problem (SNMTF), which attempts to factorize several symmetric...     

Mass spectra of flavonoids. Electron impact mass spectra of flavan-4-ols

The electron impact mass spectra of seven flavan-4-ols are reported. Fragmentation pathways were investigated using deuterium labeling and high resolution measurements. The results are consistent with previously proposed ion structures for these compounds, but indicate that the mechanisms suggested for certain hydrogen rearrangements should be revised.