Low-Loss Paper-Substrate Triple-Band-Frequency Reconfigurable Microstrip Antenna for Sub-7 GHz Applications.

In this paper, a low-cost resin-coated commercial-photo-paper substrate is used to design a printed reconfigurable multiband antenna. The two PIN diodes are used mainly to redistribute the surface current that provides reconfigurable properties to the proposed antenna. The antenna size of 40 mm × 40 mm × 0.

Quad Element MIMO Antenna for C, X, Ku, and Ka-Band Applications.

This article presents a quad-element MIMO antenna designed for multiband operation. The prototype of the design is fabricated and utilizes a vector network analyzer (VNA-AV3672D) to measure the S-parameters. The proposed antenna is capable of operating across three broad frequency bands: 3-15.

Dynamic unwrapping of nucleosomes by HsRAD51 that includes sliding and rotational motion of histone octamers.

Wrapping of genomic DNA into nucleosomes poses thermodynamic and kinetic barriers to biological processes such as replication, transcription, repair and recombination. Previous biochemical studies have demonstrated that in the presence of adenosine triphosphate (ATP) the human RAD51 (HsRAD51) recombinase can form a nucleoprotein filament (NPF) on double-stranded DNA (dsDNA) that is capable of unwrapping the nucleosomal DNA from the histone octamer (HO). Here, we have used single molecule Förster Resonance Energy Transfer (smFRET) to examine the real time nucleosome dynamics in the presence of the HsRAD51 NPF.

Hybrid phase ligation for efficient synthesis of histone proteins.

We introduce a hybrid solid-solution phase ligation approach that combines the efficiency of solid phase ligation with solution phase ligation in the total synthesis of modified histone proteins. A two linker strategy allows analysis throughout work on the solid phase and maximizes yields through cleavage at an external Rink, while an internal HMBA linker allows the native carboxyl terminus for any protein sequence. We demonstrate this approach for two histone proteins: triple-acetylated H4-K5ac, K12ac, K91ac and CENP-A-K124ac.

Probing the stabilizing effects of modified nucleotides in the bacterial decoding region of 16S ribosomal RNA.

The bacterial decoding region of 16S ribosomal RNA has multiple modified nucleotides. In order to study the role of N(4),2'-O-dimethylcytidine (m(4)Cm), the corresponding phosphoramidite was synthesized utilizing 5'-silyl-2'-ACE chemistry. Using solid-phase synthesis, m(4)Cm, 5-methylcytidine (m(5)C), 3-methyluridine (m(3)U), and 2'-O-methylcytidine (Cm) were site-specifically incorporated into small RNAs representing the decoding regions of different bacterial species.

A reversible protection strategy to improve Fmoc-SPPS of peptide thioesters by the N-Acylurea approach.

C-terminal peptide thioesters are an essential component of the native chemical ligation approach for the preparation of fully or semisynthetic proteins. However, the efficient generation of C-terminal thioesters by Fmoc solid-phase peptide synthesis remains a challenge. The recent N-acylurea approach to thioester synthesis relies on the deactivation of one amine of 3,4-diaminobenzoic acid (Dbz) during Fmoc SPPS.

Synthesis and solution conformation studies of the modified nucleoside N(4),2'-O-dimethylcytidine (m(4)Cm) and its analogues.

The dimethylated ribosomal nucleoside m(4)Cm and its monomethylated analogues Cm and m(4)C were synthesized. The conformations (syn vs anti) of the three modified nucleosides and cytidine were determined by CD and 1D NOE difference spectroscopy. The ribose sugar puckers were determined by the use of proton coupling constants.

Combined Approaches to Site-Specific Modification of RNA.

Both natural and unnatural modifications in RNA are of interest to biologists and chemists. More than 100 different analogues of the four standard RNA nucleosides have been identified in nature. Unnatural modifications are useful for structure and mechanistic studies of RNA.

Expanding the nucleotide repertoire of the ribosome with post-transcriptional modifications.

In all kingdoms of life, RNAs undergo specific post-transcriptional modifications. More than 100 different analogues of the four standard RNA nucleosides have been identified. Modifications in ribosomal RNAs (rRNAs) are highly prevalent and cluster in regions of the ribosome that have functional importance, have a high level of nucleotide conservation, and typically lack proteins.