Potential Dependent Reorientation Controlling Activity of a Molecular Electrocatalyst.

The activity of molecular electrocatalysts depends on the interplay of electrolyte composition near the electrode surface, the composition and morphology of the electrode surface, and the electric field at the electrode-electrolyte interface. This interplay is challenging to study and often overlooked when assessing molecular catalyst activity. Here, we use surface specific vibrational sum frequency generation (VSFG) spectroscopy to study the solvent and potential dependent activation of Mo(bpy)(CO)4, a CO2 reduction catalyst, at a polycrystalline Au electrode. We find that the parent complex undergoes potential dependent reorientation at the electrode surface when a small amount of N-methyl-2-pyrrolidone (NMP) is present. This preactivates the complex, resulting in greater yields at less negative potentials, of the active electrocatalyst for CO2 reduction.

Studying the cation dependence of CO2 reduction intermediates at Cu by in situ VSFG spectroscopy.

The nature of the electrolyte cation is known to have a significant impact on electrochemical reduction of CO2 at catalyst|electrolyte interfaces. An understanding of the underlying mechanism responsible for catalytic enhancement as the alkali metal cation group is descended is key to guide catalyst development. Here, we use in situ vibrational sum frequency generation (VSFG) spectroscopy to monitor changes in the binding modes of the CO intermediate at the electrochemical interface of a polycrystalline Cu electrode during CO2 reduction as the electrolyte cation is varied. A CObridge mode is observed only when using Cs+, a cation that is known to facilitate CO2 reduction on Cu, supporting the proposed involvement of CObridge sites in CO coupling mechanisms during CO2 reduction. Ex situ measurements show that the cation dependent CObridge modes correlate with morphological changes of the Cu surface.

Diabetic sensory neuropathy and insulin resistance are induced by loss of UCHL1 in Drosophila.

Diabetic sensory neuropathy (DSN) is one of the most common complications of type 2 diabetes (T2D), however the molecular mechanistic association between T2D and DSN remains elusive. Here we identify ubiquitin C-terminal hydrolase L1 (UCHL1), a deubiquitinase highly expressed in neurons, as a key molecule underlying T2D and DSN. Genetic ablation of UCHL1 leads to neuronal insulin resistance and T2D-related symptoms in Drosophila. Furthermore, loss of UCHL1 induces DSN-like phenotypes, including numbness to external noxious stimuli and axonal degeneration of sensory neurons in flies' legs. Conversely, UCHL1 overexpression improves DSN-like defects of T2D model flies. UCHL1 governs insulin signaling by deubiquitinating insulin receptor substrate 1 (IRS1) and antagonizes an E3 ligase of IRS1, Cullin 1 (CUL1). Consistent with these results, genetic and pharmacological suppression of CUL1 activity rescues T2D- and DSN-associated phenotypes. Therefore, our findings suggest a complete set of genetic factors explaining T2D and DSN, together with potential remedies for the diseases.

Aging of hair follicle stem cells and their niches.

Hair follicles in the skin undergo cyclic rounds of regeneration, degeneration, and rest throughout life. Stem cells residing in hair follicles play a pivotal role in maintaining tissue homeostasis and hair growth cycles. Research on hair follicle aging and age-related hair loss has demonstrated that a decline in hair follicle stem cell (HFSC) activity with aging can decrease the regeneration capacity of hair follicles. This review summarizes our understanding of how age-associated HFSC intrinsic and extrinsic mechanisms can induce HFSC aging and hair loss. In addition, we discuss approaches developed to attenuate ageassociated changes in HFSCs and their niches, thereby promoting hair regrowth. [BMB Reports 2023; 56(1): 2-9].

Concerns and breakthroughs of combining ionic liquids with microwave irradiation for the synthesis of Ru nanoparticles via decarbonylation.

HYPOTHESIS: Combination of microwave irradiation (MWI) and ionic liquids (IL) is widely used for the synthesis of nanoparticles (NP) via decarbonylation of zero-valent metal carbonyl precursors. However, we carefully raise a question as to whether this combination is always beneficial. Upon MWI, highly-absorbing materials such as ILs would be subject to local intense heating, likely resulting in the occurrence of localized chemical decomposition. The decomposition is expected to influence the growth mechanism of NPs due to changes in the electrostatic and steric effects. If the assumption is valid, it should be possible to decompose IL and destabilize the NPs by modifying the amplitude of the incident microwaves. In other words, it should also be possible to control the particle aggregation by circumventing the decomposition of the IL. EXPERIMENTS: A series of comparative studies were conducted using a model system (i.e. [BMIm][BF4] and Ru3(CO)12). Variables were systematically controlled. After MWI, the decrease in colloidal stability of NPs was identified. FINDINGS: In the formation of Ru NPs via decarbonylation, the association between incident microwave intensity, chemical decomposition of IL, and initiation of particle aggregation has been demonstrated. Conditions that can accelerate or alleviate the decomposition and the aggregation are also corroborated.

Catalytic Reforming of Lignin-Derived Bio-Oil Over a Nanoporous Molecular Sieve Silicoaluminophosphate-11.

Catalytic pyrolysis of lignin, a major constituent of biomass, was performed. A nanoporous molecular sieve silicoaluminophosphate-11 (SAPO-11) was selected as catalyst. Thermogravimetric analysis showed that 500 degrees C was the optimal pyrolysis temperature. Pyrolyzer-gas chromatography/mass spectroscopy was used to investigate the pyrolysis product distribution. Production of phenolics, the dominant product from the pyrolysis of lignin, was promoted by the increase in the catalyst dose. In particular, low-molecular-mass phenolics were produced more over SAPO-11, while high-molecular-mass phenolics and double-bond-containing phenolics were produced less. The fraction of aromatic compounds, including benzene, toluene, xylene, and ethylbenzene, was also increased by catalytic reforming. The catalytic effects were more pronounced when the catalyst/biomass ratio was increased. The enhanced production of aromatic compounds by an acidic catalyst obtained in this study is in good agreement with the results of previous studies.

Packaging of porcine reproductive and respiratory syndrome virus replicon RNA by a stable cell line expressing its nucleocapsid protein.

Porcine reproductive and respiratory syndrome virus (PRRSV), a member of the Arteriviridae family, is one of the most common and economically important swine pathogens. Although both live-attenuated and killed-inactivated vaccines against the virus have been available for a decade, PRRSV is still a major problem in the swine industry worldwide. To explore the possibility of producing single-round infectious PRRSV replicon particles as a potential vaccine strategy, we have now generated two necessary components: 1) a stable cell line (BHK/Sinrepl9/PRRSV-N) that constitutively expresses the viral nucleocapsid (N) protein localized to the cytoplasm and the nucleolus and 2) a PRRSV replicon vector (pBAC/PRRSV/Replicon-AN) with a 177-nucleotide deletion, removing the 3'-half portion of ORF7 in the viral genome, from which the self-replicating propagation-defective replicon RNAs were synthesized in vitro by SP6 polymerase run-off transcription. Transfection of this replicon RNA into N protein-expressing BHK-21 cells led to the secretion of infectious particles that packaged the replicon RNA, albeit with a low production efficiency of 0.4 × 10(2) to 1.1 × 10(2) infectious units/ml; the produced particles had only single-round infectivity with no cell-to-cell spread. This trans-complementation system for PRRSV provides a useful platform for studies to define the packaging signals and motifs present within the viral genome and N protein, respectively, and to develop viral replicon-based antiviral vaccines that will stop the infection and spread of this pathogen.