Nucleation and Growth Synthesis of Siloxane Gels to Form Functional,Monodisperse, and Acoustically Programmable Particles

Nucleation and growth methods offer scalable means of synthesizing colloidal particles with precisely specified size for applications in chemical research, industry, and medicine. These methods have been used to prepare a class of silicone gel particles that display a range of programmable properties and narrow size distributions. The acoustic contrast factor of these particles in water is estimated and can be tuned such that the particles undergo acoustophoresis to either the pressure nodes or antinodes of acoustic standing waves. These particles can be synthesized to display surface functional groups that can be covalently modified for a range of bioanalytical and acoustophoretic sorting applications.     

Synthetically Tuning the 2‐Position of Halogenated Quinolines: Optimizing Antibacterial and Biofilm Eradication Activities via Alkylation and Reductive Amination Pathways

Agents capable of eradicating bacterial biofilms are of great importance to human health as biofilm‐associated infections are tolerant to our current antibiotic therapies. We have recently discovered that halogenated quinoline (HQ) small molecules are: 1) capable of eradicating methicillin‐resistant Staphylococcus aureus (MRSA), methicillin‐resistant Staphylococcus epidermidis (MRSE) and vancomycin‐resistant Enterococcus faecium (VRE) biofilms, and 2) synthetic tuning of the 2‐position of the HQ scaffold has a significant impact on antibacterial and antibiofilm activities. Here, we report the chemical synthesis and biological evaluation of 39 HQ analogues that have a high degree of structural diversity at the 2‐position. We identified diverse analogues that are alkylated and aminated at the 2‐position of the HQ scaffold and demonstrate potent antibacterial (MIC≤0.39 μm ) and biofilm eradication (MBEC 1.0–93.8 μm ) activities against drug‐resistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium strains while demonstrating <5 % haemolysis activity against human red blood cells (RBCs) at 200 μm . In addition, these HQs demonstrated low cytotoxicity against HeLa cells. Halogenated quinolines are a promising class of antibiofilm agents against Gram‐positive pathogens that could lead to useful treatments against persistent bacterial infections.     

Micellar catalysis in the oxidation of lipids

The features of the catalytic effects of surfactants (S) in the oxidation of hydrocarbons and lipids are considered. It is shown that the primary amphiphilic products of the oxidation of hydroperoxides (ROOH) and lipids and the known cationic surfactants form mixed micelles {nS-mROOH} in which the accelerated decomposition of ROOH occurs and other polar components, such as metal-containing compounds, inhibitors, etc., can be concentrated, thus producing a large effect on the oxidation rate and mechanism.     

The Parameters of Bipartite Q-polynomial Distance-Regular Graphs

Let denote a bipartite distance-regular graph with diameter D 3 and valency k 3. Suppose ₀, ₁, ..., _D is a Q-polynomial ordering of the eigenvalues of . This sequence is known to satisfy the recurrence _{i – 1} – _i + _{i + 1} = 0 (0 > i > D), for some real scalar . Let q denote a complex scalar such that q + q ^–1 = . Bannai and Ito have conjectured that q is real if the diameter D is sufficiently large.We settle this conjecture in the bipartite case by showing that q is real if the diameter D 4. Moreover, if D = 3, then q is not real if and only if ₁ is the second largest eigenvalue and the pair (, k) is one of the following: (1, 3), (1, 4), (1, 5), (1, 6), (2, 4), or (2, 5). We observe that each of these pairs has a unique realization by a known bipartite distance-regular graph of diameter 3.     

Absolute quantitation of host cell proteins in recombinant human monoclonal antibodies with an automated CZE‐ESI‐MS/MS system

We report the first use of CZE for absolute characterization of host cell proteins (HCPs) in recombinant human monoclonal antibodies. An electrokinetically pumped nanoelectrospray interface was used to couple CZE with a tandem mass spectrometer. Three isotopic‐labeled peptides (LSFDKDAMVAR, VDIVENQAMDTR, and LVSDEMVVELIEK) were synthesized by direct incorporation of an isotope‐labeled lysine or arginine. The heavy‐labeled peptides were spiked in the HCP digests at known concentrations. After CZE‐ESI‐MS/MS analysis, the peaks of native and isotopic‐labeled peptides were extracted with mass tolerance ≤ 5 ppm from the electropherograms, and the ratios of peak area between native and isotopic‐labeled peptides pairs were calculated. Calibration curves (the ratios of peak area versus spiked peptide amount) with R² values of 0.999, 0.997, and 0.999 were obtained for the three HCP peptides, and the absolute amounts of the three proteins present were determined to be at the picomole level in a 20 μg sample of digested HCPs. The target proteins were present at the 7–30 ppt level in the purified HCP samples.     

Effect of surfactants on liquid-phase oxidation of hydrocarbons and lipids

A review is presented compiling new data on liquid-phase oxidation of hydrocarbons and plant oils in microheterogeneous environment formed by the addition of surfactants. Cationic surfactants catalyze the decomposition of the primary oxidation products, hydroperoxides, into free radicals thus accelerating the oxidation process. Anionic surfactants catalyze the heterolystic decomposition of hydroperoxides and therefore are excellent antioxidants for ethylbenzene, cumene, and other alkylaromatic hydrocarbons.     

Reaction of 6(7)-acyl-and 6(7)-formylperimidines with 1,3,5-triazines in poly-phosphoric acid

A method has been developed for the synthesis of 1,3,7-triazapyrenes using the reaction of 6(7)-formyl-and 6(7)-benzoylperimidines with 1,3,5-triazines in PPA. Under these conditions, 6(7)-formylperimidine reacts with 2,4,6-trimethyl-1,3,5-triazine to give 6-hydroxy-1,3-diazapyrene. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1080–1084, July, 2008.     

A New Plethysm Formula for Symmetric Functions

This paper gives a new formula for the plethysm of power-sum symmetric functions and Schur symmetric functions with one part. The form of the main result is that for b,

Dieckmann-Shapiro condensation of substituted phthalides with p-dimethylaminobenzaldehyde

Conclusion In the Dieckmann-Shapiro condensation of phthalides with p-dimethylaminobenzaldehyde the reaction rate decreases with an increase in the electron-donor effect of the substituent in the phthalide and becomes comparable to the rate of a competing reaction — Claisen condensation of ethyl acetate with the aldehyde.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khlmicheskaya, No. 8, pp. 1850–1855, August, 1986.The authors thank L. A. Sibel'dina's group for recording the PMR spectra.