Spatially resolved X ray absorption spectroscopy investigation of individual cation intercalated multi layered Ti3C2Tx MXene particles

Ti3C2Tx MXene is a two dimensional 2D material possessing highly active hydrophilic surfaces coupled with high metallic conductivity. Cations intercalation between the Ti3C2Tx nanosheets has a significant role in many applications such as water purification, desalination, and electrochemical energy storage. The pseudocapacitive charging mechanism involving surface redox reactions at the Ti3C2Tx surface enables higher energy densities than electrical double layer capacitors, and higher power densities than batteries. In this context, the oxidation state of surface Ti atoms involved in redox reactions has a high impact on the capacitance of Ti3C2Tx MXene and this can be impacted by cation intercalation. Thus, the electronic structure of multi layered Ti3C2Tx particles is investigated by X ray absorption XA spectroscopy, while also benefitting from a high spatial resolution of 30 nm from X ray photoemission electron microscopy. In this work, the XA spectra from multi layered intercalated Ti3C2Tx particles of different thicknesses were recorded at the Ti L and O K edges. The Ti oxidation state in pristine, Li , and Mg intercalated Ti3C2Tx was found to be thickness dependent, while Na and K intercalated Ti3C2Tx particles did not reveal differences upon changing thickness. This work demonstrates thickness dependent modification of the MXene surface chemistry upon cation intercalation in different individual Ti3C2Tx particle

High-Throughput Screening to Identify Plant Derived Human LDH-A Inhibitors

Aims: Lactate dehydrogenase (LDH)-A is highly expressed in diverse human malignant tumors, parallel to aggressive metastatic disease, resistance to radiation /chemotherapy and clinically poor outcome. Although this enzyme constitutes a plausible target in treatment of advanced cancer, there are few known LDH-A inhibitors. Study Design: In this work, we utilized a high-throughput enzyme micro-array format to screen and evaluate > 900 commonly used medicinal plant extracts (0.00001-.5 mg/ml) for capacity to inhibit activity of recombinant full length human LDHA; EC .1.1.1.27. Methodology: The protein sequence of purified enzyme was confirmed using 1D gel electrophoresis- MALDI-TOF-MS/MS, enzyme activity was validated by oxidation of NADH (500μM) and kinetic inhibition established in the presence of a known inhibitor (Oxalic Acid). Results: Of the natural extracts tested, the lowest IC50s [<0.001 mg/ml] were obtained by: Chinese Gallnut (Melaphis chinensis gallnut), Bladderwrack (Fucus vesiculosus), Kelp (Laminaria Japonica) and Babul (Acacia Arabica). Forty-six additional herbs contained significant LDH-A inhibitory properties with IC50s [<0.07 mg/ml], some of which have common names of Arjun, Pipsissewa, Cinnamon, Pink Rose Buds/ Petals, Wintergreen, Cat’s Claw, Witch Hazel Root and Rhodiola Root. Conclusion: These findings reflect relative potency by rank of commonly used herbs and plants that contain human LDH-A inhibitory properties. Future research will be required to isolate chemical constituents within these plants responsible for LDH-A inhibition and investigate potential therapeutic application

Fully Conjugated Graft Copolymers Comprising a P‑Type Donor–Acceptor Backbone and Poly(3-hexylthiophene) Side Chains Synthesized Via a “Graft Through” Approach

A series of fully conjugated graft copolymers containing poly­(3-hexylthiophene) (P3HT) side chains and a p-type carbazole-diketopyrrolopyrrole (CbzDPP) donor–acceptor backbone were synthesized via a graft through Suzuki polymerization. The macromonomers were formed by externally initiating P3HT growth from a boronic ester-functionalized carbazole via Kumada catalyst transfer polycondensation. Subsequently, this macromonomer was copolymerized with a DPP monomer via a graft through Suzuki polymerization to yield the final graft copolymers. The graft copolymers exhibit optical and electronic properties of both P3HT and the CbzDPP polymers independently due to the break in conjugation between the carbazole unit and P3HT chain. Moreover, these properties reflect the relative proportion of P3HT and CbzDPP polymers; shorter P3HT chain lengths lead to graft copolymers that possess more CbzDPP character and vice versa. The macromonomers were characterized by gel permeation chromatography, mass spectrometry, and UV–visible spectroscopy. The graft copolymers were further investigated using gel permeation chromatography, UV–visible spectroscopy, cyclic voltammetry, differential scanning calorimetry, and atomic force microscopy. Finally, organic field effect transistors were fabricated using the graft copolymers and compared to an analogous linear CbzDPP copolymer. Ultimately, the graft copolymers with the longest P3HT chains (ca. 75 repeat units) exhibited almost exclusively P3HT characteristics, possessing a small CbzDPP internal charge transfer (ICT) peak and only p-type conductivity (μ_h ∼ 6 × 10^–4 cm² V^–1 s^–1). Conversely, the graft copolymers with the shortest P3HT chains (ca. 10 repeat units) showed significant CbzDPP character, including a strong ICT peak and ambipolar mobilities (μ_h ∼ 5 × 10^–3 cm² V^–1 s^–1; μ_e ∼ 7 × 10^–4 cm² V^–1 s^–1)

Bioactivity-Guided Isolation of Neuritogenic Factor from the Seeds of the Gac Plant (Momordica cochinchinensis)

Nerve growth factor (NGF) is an endogenously produced protein with the capacity to induce central nervous system (CNS) neuronal differentiation and repair. NGF signaling involves its binding to tropomyosin-related kinase (Trk) receptors, internalization, and initiation of phosphorylation cascades which cause microtubule reorganization and neuronal outgrowth. Because NGF cannot cross the blood-brain barrier, its therapeutic use is limited. Synthetic peptides that can act as NGF receptor agonists (NGF mimetics) are known to attenuate neurodegenerative pathologies in experimental models of Alzheimer’s disease and Parkinson’s disease; however, the existence of plant-based NGF mimetics is uncertain. For this reason, we recently completed a high throughput screening of over 1100 nutraceuticals (vitamins, herbal plant parts, polyphenolics, teas, fruits, and vegetables) to identify neuritogenic factor using a PC-12 cell model. Remarkably we found only one, commonly known as the seed of Gac plant (Momordica cochinchinensis) (MCS). In the current study, we further investigated this seed for its neuritogenic effect using bioactivity-guided chemical separations. The data show no biological neuritogenic activity in any chemical solvent fraction, where activity was exclusive to the crude protein. MSC crude proteins were then separated by 1D electrophoresis, where the active neuritogenic activity was confirmed to have a molecular mass of approximately 17 kDa. Subsequently, the 17kDa band was excised, digested, and run on a UPLC-MS/MS with a Q Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer with data evaluated diverse tools such as X! Tandem, OMS, and K-score algorithms. Proteomic evaluation of the 17kDa band confirmed evidence for 11S globulin subunit beta, napin, oleosin, Momordica trypsin inhibitors (TI) MCoTI-I /II, and many isoforms of Two Inhibitor Peptide Topologies (TIPTOPs). While all peptides identified correspond to the genus/species, Momordica cochinchinensis and Cucumis Sativus, a significant limitation of the analysis is the nonexistence of full annotation for the Momordica cochinchinensis proteome. In conclusion, these findings demonstrate that there is a stable protein within MCS having a mass of 17kDa with the capacity to induce neurite outgrowth. Future work will be required to establish the therapeutic value of the MCS for the treatment of neurodegenerative diseases

Phase Transformation and Microstructural Evolution of CuS Electrodes in Solid State Batteries Probed by In Situ 3D X Ray Tomography

Copper sulfide shows some unique physico chemical properties that make it appealing as a cathode active material CAM for solid state batteries SSBs . The most peculiar feature of the electrode reaction is the reversible formation of m sized Cu crystals during cycling, despite its large theoretical volume change 75 . Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X ray tomography. The formation of m sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z oriented reversible displacement of the cathode pellet, which is linked to the plating stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft material

Evaluation of the Inhibitory Effects of Bavachinin and Bavachin on Human Monoamine Oxidases A and B

Monoamine oxidase B inhibitors (MAO-BIs) are used in the early management of Parkinson’s disease (PD). Long-term suspected side effects of MAO-B classical inhibitors established the need for safer alternative therapeutic agents. In our study, the flavanone bavachinin (BNN) and its analog bavachin (BVN) found in the seeds of Psoralea corylifolia L. ethanolic extract (PCSEE) were investigated for their human MAO-A and MAO-B (hMAO-A and hMAO-B) inhibition. Both PCSEE and BNN effectively reduced hMAO-B activity more than hMAO-A while BVN had activating effects. BNN showed selective hMAO-B inhibition (IC50 ~ 8.82 μM) more than hMAO-A (IC502009;~ 189.28 μM). BNN in the crude extract was determined by HPLC, also validated by TLC showing a yield of 0.21% PCSEE dry weight. BNN competitively inhibited hMAO-A and hMAO-B, with a lower hMAO-B Ki than hMAO-A Ki by 10.33-fold, and reduced hMAO-B Km/Vmax efficiency ratio to be comparable to the standard selegiline. Molecular docking examination of BNN and BVN predicted an indirect role of BNN C7-methoxy group for its higher affinity, selectivity, and reversibility as an MAO-BI. These findings suggest that BNN, which is known to be a potent PPAR-γ agonist, is a selective and competitive hMAO-B inhibitor and could be used in the management of PD

Effect of Regioregularity on Charge Transport and Structural and Excitonic Coherence in Poly(3-hexylthiophene) Nanowires

This study explores the role of very small changes in poly­(3-hexylthiophene-2,5-diyl) (P3HT) regioregularity on the physical and electronic properties of P3HT nanowires. Due to a high level of synthetic control, we are able to isolate the effects of regioregularity from those of polymer molecular weight and dispersity for the first time. A series of P3HTs with regioregularities from 96 to 99%, similar molecular weights, and low dispersities are synthesized. The charge transport properties of these polymers, along with a Soxhlet extracted 93% regioregular P3HT purchased from Rieke metals, are investigated in both thin film and nanowire transistors. The resulting structural characteristics are examined by atomic force microscopy and X-ray diffraction, and the optical characteristics are explored by UV–vis absorption. It is found that increasing the P3HT regioregularity results in improved charge transport characteristics, with an increase in mobility by a factor of 4 for the regioregularities examined. The increased mobility is shown to reflect increasing structural coherence lengths in the (010) direction, as well as improved J-aggregate characteristics due to greater planarity and reduced numbers of defect sites along the polymer nanowires. Overall, this study serves to emphasize the importance of determining and reporting even small changes in polymer regioregularity