High-Dimensional Multivariate Time Series With Additional Structure

High-dimensional multivariate time series are challenging due to the dependent and high-dimensional nature of the data, but in many applications there is additional structure that can be exploited to reduce computing time along with statistical error. We consider high-dimensional vector autoregressive processes with spatial structure, a simple and common form of additional structure. We propose novel high-dimensional methods that take advantage of such structure without making model assumptions about how distance affects dependence. We provide nonasymptotic bounds on the statistical error of parameter estimators in high-dimensional settings and show that the proposed approach reduces the statistical error. An application to air pollution in the USA demonstrates that the estimation approach reduces both computing time and prediction error and gives rise to results that are meaningful from a scientific point of view, in contrast to high-dimensional methods that ignore spatial structure. In practice, these high-dimensional methods can be used to decompose high-dimensional multivariate time series into lower-dimensional multivariate time series that can be studied by other methods in more depth. Supplementary materials for this article are available online.     

Design,Synthesis, and Application of an Optimized Monofluorinated Aliphatic Label for Peptide Studies by Solid‐State 19F NMR Spectroscopy

A conformationally restricted monofluorinated α‐amino acid, (3‐fluorobicyclo[1.1.1]pentyl)glycine (F‐Bpg), was designed as a label for the structural analysis of membrane‐bound peptides by solid‐state ¹⁹F NMR spectroscopy. The compound was synthesized and validated as a ¹⁹F label for replacing natural aliphatic α‐amino acids. Calculations suggested that F‐Bpg is similar to Leu/Ile in terms of size and lipophilicity. The ¹⁹F NMR label was incorporated into the membrane‐active antimicrobial peptide PGLa and provided information on the structure of the peptide in a lipid bilayer.     

Nucleophilic Vinyl Substitution in the Synthesis of Heterocycles. (Review)

Published data on the synthesis of various heterocyclic compounds by the reaction of nucleophiles with electrophilic olefins containing a nucleophilic group are reviewed and analyzed.     

Palladium‐Catalyzed Chemoselective and Biocompatible Functionalization of Cysteine‐Containing Molecules at Room Temperature

The third generation of aminobiphenyl palladacycle pre‐catalyst “G3‐Xantphos” enables functionalization of peptides containing cysteine in high yields. The conjugation (bioconjugation) occurs chemoselectively at room temperature under biocompatible conditions. Extension of the method to protein functionalization allows selective bioconjugation of the trastuzumab antibody.     

A Laser-Diode-Pumped Widely Tunable Single-Longitude-Mode Tm：YAP Laser at Room Temperature

A laser-diode-pumped widely tunable single-longitude-mode TIn：YAP laser in 2μm eye-safe region is built. Con- tinuous tanable range from 1899nm to 2025nm is achieved with the maximum laser output power of 225mW at 1989 am. In addition, the TIn：YAP laser operating under multimode and slngle-mode conditions is discussed.     

Modulation of photo-oxidative DNA damage by cationic surfactant complexation

The natural packaging of DNA in the cell by histones provides a particular environment affecting its sensitivity to oxidative damage. In this work, we used the complexation of DNA by cationic surfactants to modulate the conformation, the dynamics, and the environment of the double helix. Photo-oxidative damage initiated by benzophenone as the photosensitizer on a plasmid DNA complexed by dodecyltrimethylammonium chloride (DTAC), tetradecyltrimethylammonium chloride (TTAC), cetyltrimethyammonium chloride (CTAC) and bromide (CTAB) was detected by agarose gel electrophoresis. By fluorescent titration in the presence of ethidium bromide (EB) and agarose gel electrophoresis, we experimentally confirmed the complexation diagrams with a critical aggregation concentration on DNA matrix (CAC DNA) delimiting two regions of complexation, according to the DNA-phosphate concentration. The study of the photo-oxidative damage shows, for the first time, a direct correlation between the DNA complexation by these surfactants and the efficiency of DNA cleavage, with a maximum corresponding to the CAC DNA for DTAC and CTAC, and to DNA neutralization for CTAC and CTAB. The localization of a photosensitizer having low water solubility, such as benzophenone, inside the hydrophobic domains formed by the surfactant aggregated on DNA, locally increases the photoinduced cleavage by the free radical oxygen species generated. The inefficiency of a water-soluble quencher of hydroxyl radicals, such as mannitol, confirmed this phenomenon. The detection of photo-oxidative damage constitutes a new tool for investigating DNA complexation by cationic surfactants. Moreover, highlighting the drastically increased sensitivity of a complexed DNA to photo-oxidative damage is of crucial importance for the biological use of surfactants as nonviral gene delivery systems.     

Synthesis,Antibacterial and Antifungal Activity of New 3-Aryl-5H-pyrrolo[1,2-a]imidazole and 5H-Imidazo[1,2-a]azepine Quaternary Salts

A series of novel 3-aryl-5H-pyrrolo[1,2-a]imidazole and 5H-imidazo[1,2-a]azepine quaternary salts were synthesized in 58–85% yields via the reaction of 3-aryl-6, 7-dihydro-5H-pyrrolo[1,2-a]imidazoles or 3-aryl-6,7,8,9-tetrahydro-5H-imidazo[1,2-a]azepines and various alkylating reagents. All compounds were characterized by ¹H NMR, ¹³C NMR, and LC-MS. The conducted screening studies of the in vitro antimicrobial activity of the new quaternary salts derivatives established that 15 of the 18 newly synthesized compounds show antibacterial and antifungal activity. Synthesized 3-(3,4-dichlorohenyl)-1-[(4-phenoxyphenylcarbamoyl)-methyl]-6,7-dihydro-5H-pyrrolo[1,2-a]imidazol-1-ium chloride 6c possessed a broad activity spectrum towards Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Cryptococcus neoformans, with a high hemolytic activity against human red blood cells and cytotoxicity against HEK-293. However, compound 6c is characterized by a low in vivo toxicity in mice (LD₅₀ > 2000 mg/kg).