Electron Cloaking in MoS for High-Performance Optoelectronics.

Defects in two-dimensional (2D) materials represent both challenges and opportunities to their optoelectronic performance. While defects limit the carrier mobility in transistors through increased charge scattering, they also enhance 2D material functionality in sensors. Electron cloaking, a process that reduces Coulomb scattering via localized electron-defect interactions, has recently been shown to mitigate the performance degradation of bulk semiconductors in the presence of defects.

Enhancing the Electrochemical Activity of 2D Materials Edges through Oriented Electric Fields.

The edges of 2D materials have emerged as promising electrochemical catalyst systems, yet their performance still lags behind that of noble metals. Here, we demonstrate the potential of oriented electric fields (OEFs) to enhance the electrochemical activity of 2D materials edges. By atomically engineering the edge of a fluorographene/graphene/MoS heterojunction nanoribbon, strong and localized OEFs were realized as confirmed by simulations and spatially resolved spectroscopy.

An enantioselective formal synthesis of thienamycin.

Thienamycin is a carbapenem antibiotic with potent activity against gram-negative and gram-positive bacteria. Due to its promising activity but lack of chemical stability, thienamycin serves as inspiration for new synthetic antibiotic scaffolds. In this study, we report a nine-step enantioselective formal synthesis of thienamycin.

Total Synthesis of Dynobactin A.

The first total synthesis of the potent antimicrobial agent dynobactin A is disclosed. This synthesis enlists a singular aziridine ring opening strategy to access the two disparate β-aryl-branched amino acids present within this complex decapeptide. Featuring a number of unique maneuvers to navigate inherently sensitive and epimerizable functional groups, this convergent approach proceeds in only 16 steps (LLS) from commercial materials and should facilitate the synthesis of numerous analogues for medicinal chemistry studies.

Atroposelective Total Synthesis of Darobactin A.

A concise, modular synthesis of the novel antibiotic darobactin A is disclosed. The synthesis successfully forges the hallmark strained macrocyclic ring systems in a sequential fashion. Key transformations include two atroposelective Larock-based macrocyclizations, one of which proceeds with exquisite regioselectivity despite bearing an unprotected alkyne.

Stereoselective Synthesis of the Spirocyclic γ-Lactam Core of the Ansalactams.

Ansalactam A is an ansa macrolide natural product that contains a densely functionalized spiro-γ-lactam core containing three contiguous stereocenters. This unusual motif distinguishes it from other members of this family and represents a significant synthetic challenge. Herein, we report the development of a stereoselective formal [3+2] cycloaddition reaction for the construction of this key spiro-γ-lactam motif for the first time, thereby enabling access to the northern domain of ansalactam A.

Leveraging Marine Natural Products as a Platform to Tackle Bacterial Resistance and Persistence.

Antimicrobial resistance to existing antibiotics represents one of the greatest threats to human health and is growing at an alarming rate. To further complicate treatment of bacterial infections, many chronic infections are the result of bacterial biofilms that are tolerant to treatment with antibiotics because of the presence of metabolically dormant persister cell populations. Together these threats are creating an increasing burden on the healthcare system, and a "preantibiotic" age is on the horizon if significant action is not taken by the scientific and medical communities.

Concise Synthesis and Antimicrobial Evaluation of the Guanidinium Alkaloid Batzelladine D: Development of a Stereodivergent Strategy.

Herein, we describe a stereodivergent route to (±)-batzelladine D (), (+)-batzelladine D (), (-)-batzelladine D (), and a series of stereochemical analogues and explore their antimicrobial activity for the first time. The concise synthetic approach enables access to the natural products in a sequence of 8-12 steps from readily available building blocks. Highlights of the synthetic strategy include gram-scale preparation of a late stage intermediate, pinpoint stereocontrol around the tricyclic skeleton, and a modular strategy that enables analogue generation.

JPEG2000 still image coding quality.

This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation.

A novel medical image quality index.

A novel medical image quality index using grey relational coefficient calculation is proposed in this study. Three medical modalities, DR, CT and MRI, using 30 or 60 images with a total of 120 images used for experimentation. These images were first compressed at ten different compression ratios (10 ∼ 100) using a medical image compression algorithm named JJ2000.