The role of manganese in CoMnO catalysts for selective long-chain hydrocarbon production via Fischer-Tropsch synthesis.

Cobalt is an efficient catalyst for Fischer-Tropsch synthesis (FTS) of hydrocarbons from syngas (CO + H) with enhanced selectivity for long-chain hydrocarbons when promoted by Manganese. However, the molecular scale origin of the enhancement remains unclear. Here we present an experimental and theoretical study using model catalysts consisting of crystalline CoMnO nanoparticles and thin films, where Co and Mn are mixed at the sub-nm scale.

PanKB: An interactive microbial pangenome knowledgebase for research, biotechnological innovation, and knowledge mining.

The exponential growth of microbial genome data presents unprecedented opportunities for unlocking the potential of microorganisms. The burgeoning field of pangenomics offers a framework for extracting insights from this big biological data. Recent advances in microbial pangenomic research have generated substantial data and literature, yielding valuable knowledge across diverse microbial species.

Multilaminate Energy Storage Films from Entropy-Driven Self-Assembled Supramolecular Nanocomposites.

Composite materials comprising polymers and inorganic nanoparticles (NPs) are promising for energy storage applications, though challenges in controlling NP dispersion often result in performance bottlenecks. Realizing nanocomposites with controlled NP locations and distributions within polymer microdomains is highly desirable for improving energy storage capabilities but is a persistent challenge, impeding the in-depth understanding of the structure-performance relationship. In this study, a facile entropy-driven self-assembly approach is employed to fabricate block copolymer-based supramolecular nanocomposite films with highly ordered lamellar structures, which are then used in electrostatic film capacitors.

Prevention of vertical transmission of HIV in Khayelitsha, South Africa: A contemporary review of services after 20 years.

Background: The first vertical transmission of HIV prevention (VTP) programme in South Africa was launched in 1999 in Khayelitsha, Western Cape Province (WC). Since then, VTP guidelines have expanded in complexity and scope.

Objectives: To describe contemporary VTP uptake in Khayelitsha and quantify vertical transmission (VT) risk factors based on linked routine electronic health data.

Observation of an Orientational Glass in a Superlattice of Elliptically-Faceted CdSe Nanocrystals.

Extensive prior work has shown that colloidal inorganic nanocrystals coated with organic ligand shells can behave as artificial atoms and, as such, form superlattices with different crystal structures and packing densities. Although ordered superlattices present a high degree of long-range positional order, the relative crystallographic orientation of the inorganic nanocrystals with respect to each other tends to be random. Recent works have shown that superlattices can achieve orientational alignment through combinations of nanocrystal faceting and ligand modification, as well as selective metal particle attachment to particular facets.

Multiscale Characterization of the Influence of the Organic-Inorganic Interface on the Dielectric Breakdown of Nanocomposites.

Nanoscale engineered materials such as nanocomposites can display or be designed to enhance their material properties through control of the internal interfaces. Here, we unveil the nanoscale origin and important characteristics of the enhanced dielectric breakdown capabilities of gold nanoparticle/polymer nanocomposites. Our multiscale approach spans from the study of a single chemically designed organic/inorganic interface to micrometer-thick films.

DNA Input Classification by a Riboregulator-Based Cell-Free Perceptron.

The ability to recognize molecular patterns is essential for the continued survival of biological organisms, allowing them to sense and respond to their immediate environment. The design of synthetic gene-based classifiers has been explored previously; however, prior strategies have focused primarily on DNA strand-displacement reactions. Here, we present a synthetic in vitro transcription and translation (TXTL)-based perceptron consisting of a weighted sum operation (WSO) coupled to a downstream thresholding function.

An analysis of the HIV testing cascade of a group of HIV-exposed infants from birth to 18 months in peri-urban Khayelitsha, South Africa.

Background: Despite the reduction of HIV mother-to-child transmission, there are concerns regarding transmission rate in the breastfeeding period. We describe the routine uptake of 6 or 10 (6/10) weeks, 9 months and 18 months testing, with and without tracing, in a cohort of infants who received HIV PCR testing at birth (birth PCR) (with and without point of care (POC) testing) in a peri-urban primary health care setting in Khayelitsha, South Africa.

Methods: In this cohort study conducted between November 2014 and February 2018, HIV-positive mothers and their HIV-exposed babies were recruited at birth and all babies were tested with birth PCR.

Cell-Free Characterization of Coherent Feed-Forward Loop-Based Synthetic Genetic Circuits.

Regulatory pathways inside living cells employ feed-forward architectures to fulfill essential signal processing functions that aid in the interpretation of various types of inputs through noise-filtering, fold-change detection and adaptation. Although it has been demonstrated computationally that a coherent feed-forward loop (CFFL) can function as noise filter, a property essential to decoding complex temporal signals, this motif has not been extensively characterized experimentally or integrated into larger networks. Here we use post-transcriptional regulation to implement and characterize a synthetic CFFL in an cell-free transcription-translation system and build larger composite feed-forward architectures.

Conformation, and Charge Tunneling through Molecules in SAMs.

This paper demonstrates that the molecular conformation (in addition to the composition and structure) of molecules making up self-assembled monolayers (SAMs) influences the rates of charge tunneling (CT) through them, in molecular junctions of the form Au/S(CH)CONRR//GaO/EGaIn, where R and R are alkyl chains of different length. The lengths of chains R and R were selected to influence the conformations and conformational homogeneity of the molecules in the monolayer. The conformations of the molecules influence the thickness of the monolayer (i.

Light-Activated Signaling in DNA-Encoded Sender-Receiver Architectures.

Collective decision making by living cells is facilitated by exchange of diffusible signals where sender cells release a chemical signal that is interpreted by receiver cells. A variety of nonliving artificial cell models have been developed in recent years that mimic various aspects of diffusion-based intercellular communication. However, localized secretion of diffusive signals from individual protocells, which is critical for mimicking biological sender-receiver systems, has remained challenging to control precisely.

Spontaneous Emergence of Self-Replicating Molecules Containing Nucleobases and Amino Acids.

The conditions that led to the formation of the first organisms and the ways that life originates from a lifeless chemical soup are poorly understood. The recent hypothesis of "RNA-peptide coevolution" suggests that the current close relationship between amino acids and nucleobases may well have extended to the origin of life. We now show how the interplay between these compound classes can give rise to new self-replicating molecules using a dynamic combinatorial approach.

A Multilayer Microfluidic Platform for the Conduction of Prolonged Cell-Free Gene Expression.

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic regulatory circuits. The analysis of synthetic genetic regulatory networks in vivo is time consuming and suffers from a lack of environmental control, with exogenous synthetic components interacting with host processes resulting in undesired behavior. To overcome these issues, cell-free characterization of novel circuitry is becoming more prevalent.

DNA-based communication in populations of synthetic protocells.

Developing molecular communication platforms based on orthogonal communication channels is a crucial step towards engineering artificial multicellular systems. Here, we present a general and scalable platform entitled 'biomolecular implementation of protocellular communication' (BIO-PC) to engineer distributed multichannel molecular communication between populations of non-lipid semipermeable microcapsules. Our method leverages the modularity and scalability of enzyme-free DNA strand-displacement circuits to develop protocellular consortia that can sense, process and respond to DNA-based messages.

Cell-free microcompartmentalised transcription-translation for the prototyping of synthetic communication networks.

Recent efforts in synthetic biology have shown the possibility of engineering distributed functions in populations of living cells, which requires the development of highly orthogonal, genetically encoded communication pathways. Cell-free transcription-translation (TXTL) reactions encapsulated in microcompartments enable prototyping of molecular communication channels and their integration into engineered genetic circuits by mimicking critical cell features, such as gene expression, cell size, and cell individuality within a community. In this review, we discuss the uses of cell-free transcription-translation reactions for the development of synthetic genetic circuits, with a special focus on the use of microcompartments supporting this reaction.

Sigma Factor-Mediated Tuning of Bacterial Cell-Free Synthetic Genetic Oscillators.

Cell-free transcription-translation provides a simplified prototyping environment to rapidly design and study synthetic networks. Despite the presence of a well characterized toolbox of genetic elements, examples of genetic networks that exhibit complex temporal behavior are scarce. Here, we present a genetic oscillator implemented in an E.

The Rate of Charge Tunneling in EGaIn Junctions Is Not Sensitive to Halogen Substituents at the Self-Assembled Monolayer//GaO Interface.

This paper describes experiments that are designed to test the influence of terminal groups incorporating carbon-halogen bonds on the current density (by hole tunneling) across self-assembled monolayer (SAM)-based junctions of the form M/S(CH)NHCOCH X//GaO/EGaIn (where M = Ag and Au and X = CH, F, Cl, Br, I). Within the limits of statistical significance, these rates of tunneling are insensitive to the nature of the terminal group at the interface between the SAM and the GaO. The results are relevant to the origin of an apparent inconsistency in the literature concerning the influence of halogen atoms at the SAM//electrode interface on the tunneling current density.

Affinity Maturation of a Cyclic Peptide Handle for Therapeutic Antibodies Using Deep Mutational Scanning.

Meditopes are cyclic peptides that bind in a specific pocket in the antigen-binding fragment of a therapeutic antibody such as cetuximab. Provided their moderate affinity can be enhanced, meditope peptides could be used as specific non-covalent and paratope-independent handles in targeted drug delivery, molecular imaging, and therapeutic drug monitoring. Here we show that the affinity of a recently reported meditope for cetuximab can be substantially enhanced using a combination of yeast display and deep mutational scanning.

Kinetic Analysis as a Tool to Distinguish Pathway Complexity in Molecular Assembly: An Unexpected Outcome of Structures in Competition.

While the sensitive dependence of the functional characteristics of self-assembled nanofibers on the molecular structure of their building blocks is well-known, the crucial influence of the dynamics of the assembly process is often overlooked. For natural protein-based fibrils, various aggregation mechanisms have been demonstrated, from simple primary nucleation to secondary nucleation and off-pathway aggregation. Similar pathway complexity has recently been described in synthetic supramolecular polymers and has been shown to be intimately linked to their morphology.

Colorful protein-based fluorescent probes for collagen imaging.

Real-time visualization of collagen is important in studies on tissue formation and remodeling in the research fields of developmental biology and tissue engineering. Our group has previously reported on a fluorescent probe for the specific imaging of collagen in live tissue in situ, consisting of the native collagen binding protein CNA35 labeled with fluorescent dye Oregon Green 488 (CNA35-OG488). The CNA35-OG488 probe has become widely used for collagen imaging.

Evaluation of the portal venous system: complementary roles of invasive and noninvasive imaging strategies.

Evaluation of the portal venous system is required in several clinical circumstances, including before and after liver transplantation, before creation of a transjugular intrahepatic portosystemic shunt, in the clinical setting of bowel ischemia, or to evaluate varices. Several noninvasive modalities (magnetic resonance [MR] imaging and MR angiography, computed tomography [CT], and ultrasound [US]) are available for evaluation of the portal venous system in addition to the invasive angiographic methods. In most clinical circumstances, either CT or MR imaging and MR angiography in combination with US of the liver vasculature will allow complete evaluation of the portal venous system.

Imaging findings in Caroli's disease.

In 1958 Jacques Caroli described communicating cavernous ectasia of the biliary tree as an uncommon cause of chronic, often life-threatening hepatobiliary disease. The disease now most often referred to as Caroli's disease is a rare condition characterized by nonobstructive saccular or fusiform dilatation of the intrahepatic bile ducts. In the so-called pure form, dilatation is classically segmental and saccular and is associated with stone formation and recurrent bacterial cholangitis.