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1.
Clin Cancer Res ; 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-39150517

ABSTRACT

PURPOSE: Anti-PD-1/L1 has been demonstrated for its efficacy when combined with cytotoxic chemotherapy in randomized phase 3 trials for advanced biliary tract cancer (BTC). However, no biomarker predictive of benefit has been established for anti-PD-1/L1 in BTC. Here, we evaluated tumor-infiltrating lymphocytes (TILs) using artificial intelligence-powered immune phenotype (AI-IP) analysis in advanced BTC treated with anti-PD-1. PATIENTS AND METHODS: Pre-treatment H&E-stained whole-slide images from 339 advanced BTC patients who received anti-PD-1 as second-line treatment or beyond, were utilized for AI-IP analysis and correlative analysis between AI-IP and efficacy outcomes with anti-PD-1. Next, data and images of BTC cohort from The Cancer Genome Atlas (TCGA) were additionally analyzed to evaluate the transcriptomic and mutational characteristics of various AI-IPs in BTC. RESULTS: Overall, AI-IPs were classified as inflamed (high intratumoral TIL [iTIL]) in 40 patients (11.8%), immune-excluded (low iTIL and high stromal TIL) in 167 (49.3%), and immune-deserted (low TIL overall) in 132 (38.9%). The inflamed IP group showed a significantly higher overall response rate compared to the non-inflamed IP groups (27.5% vs. 7.7%, P<0.001). Median overall survival and progression-free survival were significantly longer in the inflamed IP group than in the non-inflamed IP group (OS: 12.6 vs. 5.1 months, P=0.002; PFS: 4.5 vs. 1.9 months, P<0.001). In the analysis using TCGA cohort, the inflamed IP showed increased cytolytic activity scores and an interferon-gamma signature compared to the non-inflamed IP. CONCLUSIONS: AI-powered IP based on spatial TIL analysis was effective in predicting the efficacy outcomes in patients with BTC treated with anti-PD-1.

2.
Hepatol Commun ; 8(8)2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39101773

ABSTRACT

BACKGROUND: Intermediate cell carcinoma (Int-CA) is a rare and enigmatic primary liver cancer characterized by uniform tumor cells exhibiting mixed features of both HCC and intrahepatic cholangiocarcinoma. Despite the unique pathological features of int-CA, its molecular characteristics remain unclear yet. METHODS: RNA sequencing and whole genome sequencing profiling were performed on int-CA tumors and compared with those of HCC and intrahepatic cholangiocarcinoma. RESULTS: Int-CAs unveiled a distinct and intermediate transcriptomic feature that is strikingly different from both HCC and intrahepatic cholangiocarcinoma. The marked abundance of splicing events leading to intron retention emerged as a signature feature of int-CA, along with a prominent expression of Notch signaling. Further exploration revealed that METTL16 was suppressed within int-CA, showing a DNA copy number-dependent transcriptional deregulation. Notably, experimental investigations confirmed that METTL16 suppression facilitated invasive tumor characteristics through the activation of the Notch signaling cascade. CONCLUSIONS: Our results provide a molecular landscape of int-CA featured by METTL16 suppression and frequent intron retention events, which may play pivotal roles in the acquisition of the aggressive phenotype of Int-CA.


Subject(s)
Carcinoma, Hepatocellular , Cholangiocarcinoma , Gene Expression Profiling , Liver Neoplasms , Humans , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cholangiocarcinoma/genetics , Cholangiocarcinoma/pathology , Transcriptome , Male , Methyltransferases/genetics , Methyltransferases/metabolism , Signal Transduction/genetics , Gene Expression Regulation, Neoplastic , Bile Duct Neoplasms/genetics , Bile Duct Neoplasms/pathology , Female , Middle Aged
3.
Anal Chem ; 96(35): 14178-14185, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39169664

ABSTRACT

Blood cell counting typically requires complex machinery. Flow cytometers used for this purpose involve precise optical alignment, costly detectors, and pretreatment with fluorescent labels. Coulter countertype devices, which monitor ion current, are simpler. However, conventional Coulter counters provide only information about size, making it impossible to distinguish similarly sized lymphocytes from red blood cells (RBCs). Inspired by the fact that RBCs have an exceptionally high propensity to absorb light and convert it to heat, i.e., photothermal effect, this study proposes integrating photothermal phenomena into a microfluidic Coulter counting chip. Photothermal heat selectively amplifies the ion current from RBCs over other components including lymphocytes. The combination of ion current monitoring and the photothermal effect for RBC counting suggests an evolution toward versatile flow cytometers.


Subject(s)
Erythrocytes , Flow Cytometry , Erythrocytes/cytology , Erythrocytes/chemistry , Humans , Flow Cytometry/methods , Ions/chemistry
4.
ACS Omega ; 9(29): 31864-31870, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39072101

ABSTRACT

Magnesium, calcium, and barium heteroleptic complexes were synthesized by the substitution reaction of the bis(trimethylsilyl)amide of Mg(btsa)2·DME, Ca(btsa)2·DME, and Ba(btsa)2·2DME with an ethereal group and hfac ligands (btsa = bis(trimethylsilyl)amide, DME = dimethoxyethane). The compounds Mg(dts)(hfac)2 (1), Ca(dts)(hfac)2 (2), Mg(dmts)(hfac)2 (3), Ca(dmts)(hfac)2 (4), and Ba(dmts)(hfac)2 (5) were fabricated and analyzed using various techniques, including Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetric analyses, and elemental analysis (dts = 2,2-dimethyl-3,6,9-trioxa-2-siladecane, dmts = 2,2-dimethyl-3,6,9,12-tetraoxa-2-silatridecane, hfac = hexafluoroacetylacetonate). The structures of complexes 2, 4, and 5 were confirmed using single-crystal X-ray crystallography; all complexes display monomeric structures. All compounds underwent trimethylsilylation of the coordinating ethereal alcohols (meeH and tmgeH) in the presence of HMDS as byproducts because of their increasing acidity originating from the electron-withdrawing hfac ligands. (meeH = 2-(2-methoxyethoxy)ethan-1-ol, tmgeH = tri(ethylene glycol) monoethyl ether, HMDS = hexamethyldisilazane).

5.
ACS Omega ; 9(29): 31871-31877, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39072115

ABSTRACT

We report the synthesis and characterization of novel antimony(III) complexes: Sb(mpa)3 (1), Sb(mmpa)3 (2), Sb(mdpa)3 (3), Sb(epa)3 (4), Sb(empa)3 (5), and Sb(edpa)3 (6) (mpa = N-methoxypropanamide, mmpa = N-methoxy-2-methyl-propanamide, mdpa = N-methoxy-2,2-dimethylpropanamide, epa = N-ethoxypropanamide, empa = N-ethoxy-2-methylpropanamide, and edpa = N-ethoxy-2,2-dimethylpropanamide, via a salt-elimination reaction with SbCl3 and sodium-substituted carboxamide. The molecular structure of 6 revealed the formation of a homoleptic conformer with a highly distorted pentagonal bipyramidal geometry, as determined by X-ray crystallography. Thermogravimetric analysis showed excellent volatility at elevated temperatures, with complex 4 displaying the lowest residual mass of 0.16% at 500 °C. For complexes 4, 5, and 6, the temperature at a vapor pressure of 1 Torr and the enthalpy of vaporization were estimated to be 58, 64, and 45 °C and 83.31, 103.58, and 99.93 kJ/mol, respectively.

6.
ACS Omega ; 9(26): 28707-28714, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38973851

ABSTRACT

This study describes the synthesis of germanium and tin complexes Ge(mdpaS)2 (1), Ge(edpaS)2 (2), Ge(bdpaS)2 (3), Ge(empaS)2 (4), Sn(mdpaS)2 (5), Sn(edpaS)2 (6), Sn(bdpaS)2 (7), and Sn(empaS)2 (8) (mdpaSH = (Z)-N-methoxy-2,2-dimethylpropanimidothioic acid; edpaSH = (Z)-N-ethoxy-2,2-dimethylpropanimidothioic acid; bdpaSH = (Z)-N-(tert-butoxy)-2,2-dimethylpropanimidothioic acid; empaSH = (Z)-N-ethoxy-2-methylpropanimidothioic acid), using newly designed N-alkoxy thioamide ligands as precursors for metal chalcogenide materials. All complexes were characterized using various analytical techniques, and the single-crystal structures of complexes 5 and 7 revealed a distorted seesaw geometry in the monomeric SnL2 form. Thermogravimetric (TG) curves showed differences between Ge compounds, which exhibited single-step weight losses, and Sn compounds, which exhibited multistep weight losses. As a result, we suggest that the synthesized complexes 1-8 are potential precursors for group IV metal chalcogenide materials.

7.
Hum Pathol ; 149: 55-65, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38876199

ABSTRACT

Histological subtyping of hepatocellular carcinoma (HCC) is challenging in the presence of histological heterogeneity, where distinctly different morphological patterns are present within the same tumor. Current approaches rely on percent cut-offs. We hypothesized that morphologic intratumor heterogeneity is a non-random biological feature and that incorporating recurrent patterns would improve histological subtyping of HCC. Resected HCC were studied and the overall frequency of morphologic intratumor heterogeneity was 45% in 242 specimens. Steatohepatitic HCC (SH-HCC) had the highest frequency of morphologic intratumor heterogeneity (91%); this was confirmed in additional cohorts of SH-HCC from different medical centers (overall frequency of 78% in SH-HCC). Morphologic intratumor heterogeneity in SH-HCC showed distinct and recurrent patterns that could be classified as early, intermediate, and advanced. Incorporating these patterns into the definition of SH-HCC allowed successful resolution of several persistent challenges: the problem of the best cut-off for subtyping SH-HCC, the problem of the relationship between SH-HCC and scirrhous HCC, and the classification for HCC with abundant microvesicular steatosis. This approach also clarified the relationship between SH-HCC and CTNNB1 mutations, showing that CTNNB1 mutations occur late in a subset of SH-HCC. In summary, there is a high frequency of morphologic intratumor heterogeneity in HCC. Incorporating this finding into histological subtyping resolved several persistent problems with the SH-HCC subtype.


Subject(s)
Carcinoma, Hepatocellular , Fatty Liver , Liver Neoplasms , Mutation , beta Catenin , Humans , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , beta Catenin/genetics , Male , Female , Middle Aged , Fatty Liver/pathology , Fatty Liver/complications , Aged , Adult , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics
8.
Article in English | MEDLINE | ID: mdl-38664939

ABSTRACT

Dynamic random-access memory (DRAM) capacitor electrodes, exemplified by TiN, face performance limitations owing to their relatively low work functions in addition to the formation of a low-k interfacial layer caused by their insufficient chemical stability. With recent advances in device scaling, these issues have become increasingly problematic, prompting the exploration of alternative electrode materials to replace TiN. Molybdenum dioxide (MoO2) has emerged as a promising candidate for this application, outperforming TiN due to its low resistivity, high work function (>5 eV), and excellent chemical stability. Moreover, monoclinic MoO2 exhibits a distorted rutile structure, enabling the in situ growth of high-k rutile TiO2 on MoO2 at low deposition temperatures. However, MoO2 deposition poses challenges because of its metastable nature compared to the more stable molybdenum oxide (MoOx) phases, such as MoO3 and Mo4O11. In this work, we successfully fabricated Sn-doped MoOx (TMO) films by atomic layer deposition (ALD) at 300 °C. A stabilized monoclinic MoO2 phase was achieved using ALD by incorporating SnOx into MoOx on both SiO2 and TiN substrates. The ALD TMO process comprised MoOx and SnOx subcycles, and the MoOx:SnOx subcycle ratio was varied from 100:1 to 20:1. High growth rates ranging from 0.19 to 0.34 nm/cycle were achieved for ALD TMO with varying the MoOx:SnOx subcycle ratio from 20:1 to 100:0. After post-deposition annealing at 500 °C, polycrystalline TMO films were obtained with smooth surface morphology. ALD TMO exhibited excellent interface quality with ALD TiO2, possessing a negligible low-k interfacial layer. Moreover, a rutile TiO2 film with a high dielectric constant of 136 was successfully grown on a 20% Sn-TMO electrode. Overall, this study provides a strategy to stabilize metastable MoO2 films using ALD, and it demonstrates the superiority of ALD TMO as a promising DRAM capacitor electrode material.

9.
Nat Commun ; 15(1): 2138, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38459015

ABSTRACT

The advanced patterning process is the basis of integration technology to realize the development of next-generation high-speed, low-power consumption devices. Recently, area-selective atomic layer deposition (AS-ALD), which allows the direct deposition of target materials on the desired area using a deposition barrier, has emerged as an alternative patterning process. However, the AS-ALD process remains challenging to use for the improvement of patterning resolution and selectivity. In this study, we report a superlattice-based AS-ALD (SAS-ALD) process using a two-dimensional (2D) MoS2-MoSe2 lateral superlattice as a pre-defining template. We achieved a minimum half pitch size of a sub-10 nm scale for the resulting AS-ALD on the 2D superlattice template by controlling the duration time of chemical vapor deposition (CVD) precursors. SAS-ALD introduces a mechanism that enables selectivity through the adsorption and diffusion processes of ALD precursors, distinctly different from conventional AS-ALD method. This technique facilitates selective deposition even on small pattern sizes and is compatible with the use of highly reactive precursors like trimethyl aluminum. Moreover, it allows for the selective deposition of a variety of materials, including Al2O3, HfO2, Ru, Te, and Sb2Se3.

10.
Anal Chem ; 2024 Feb 11.
Article in English | MEDLINE | ID: mdl-38341845

ABSTRACT

Monitoring the dendritic electrodeposition process is crucial in various fields such as energy storage devices and sensors. A variety of in situ dendritic growth monitoring methods have been developed, especially for battery applications, but they require specialized cells and equipment and are often invasive, making them unsuitable for various electrochemical systems and commercial batteries. To address these challenges, a real-time impedance analysis technique was used to determine dendritic electrodeposition on microelectrodes. The "effective size" of the electrodeposit was extracted from the impedance data, and the dendritic growth was assessed in real-time by comparing "effective size" to a theoretical radius assuming hemispherical growth. The technique was validated using scanning electron microscopy imaging and finite element method simulation. Initially applied to gold electrodeposition, the method was extended to zinc electrodeposition, demonstrating potential utilization for energy storage systems.

11.
J Chem Phys ; 160(2)2024 Jan 14.
Article in English | MEDLINE | ID: mdl-38189606

ABSTRACT

Alkoxide precursors have been highlighted for depositing carbon-free films, but their use in Atomic Layer Deposition (ALD) often exhibits a non-saturated growth. This indicates no self-limiting growth due to the chain reaction of hydrolysis or ligand decomposition caused by ß-hydride elimination. In the previous study, we demonstrated that self-limiting growth of ALD can be achieved using our newly developed precursor, hafnium cyclopentadienyl tris(N-ethoxy-2,2-dimethyl propanamido) [HfCp(edpa)3]. To elucidate the growth mechanism and the role of cyclopentadienyl (Cp) ligand in a heteroleptic alkoxide precursor, herein, we compare homoleptic and heteroleptic Hf precursors consisting of N-ethoxy-2,2-dimethyl propanamido (edpa) ligands with and without cyclopentadienyl ligand-hafnium tetrakis(N-ethoxy-2,2-dimethyl propanamido) [Hf(edpa)4] and HfCp(edpa)3. We also investigate the role of a Cp ligand in growth characteristics. By substituting an alkoxide ligand with a Cp ligand, we could modify the surface reaction during ALD, preventing undesired reactions. The last remaining edpa after Hf(edpa)4 adsorption can undergo a hydride elimination reaction, resulting in surface O-H generation. In contrast, Cp remains after the HfCp(edpa)3 adsorption. Accordingly, we observe proper ALD growth with self-limiting properties. Thus, a comparative study of different ligands of the precursors can provide critical clues to the design of alkoxide precursors for obtaining typical ALD growth with a saturation behavior.

12.
ACS Appl Mater Interfaces ; 16(3): 3082-3092, 2024 Jan 24.
Article in English | MEDLINE | ID: mdl-38206769

ABSTRACT

Advancements in neural interface technologies have enabled the direct connection of neurons and electronics, facilitating chemical communication between neural systems and external devices. One promising approach is a synaptogenesis-involving method, which offers an opportunity for synaptic signaling between these systems. Janus synapses, one type of synaptic interface utilizing synaptic cell adhesion molecules for interface construction, possess unique features that enable the determination of location, direction of signal flow, and types of neurotransmitters involved, promoting directional and multifaceted communication. This study presents the first successful establishment of a Janus synapse between dopaminergic (DA) neurons and abiotic substrates by using a neuroligin-2 (NLG2)-mediated synapse-inducing method. NLG2 immobilized on gold-coated microspheres can induce synaptogenesis upon contact with spatially isolated DA axons. The induced DA Janus synapses exhibit stable synaptic activities comparable to that of native synapses over time, suggesting their suitability for application in neural interfaces. By calling for DA presynaptic organizations, the NLG2-immobilized abiotic substrate is a promising tool for the on-site detection of synaptic dopamine release.


Subject(s)
Neuroligins , Presynaptic Terminals , Presynaptic Terminals/metabolism , Dopamine/metabolism , Microspheres , Neurons , Synapses/physiology
13.
Small Methods ; 8(7): e2301284, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38155148

ABSTRACT

High-entropy alloys (HEAs), especially in the form of compositional complex solid solutions (CCSS), have gained attention in the field of electrocatalysis. However, exploring their vast composition space concerning their electrocatalytic properties imposes significant challenges. Scanning electrochemical cell microscopy (SECCM) offers high-speed electrochemical analysis on surface areas with a lateral resolution down to tens of nm. However, high-precision piezo positioners often used for the motion of the tip limit the area of SECCM scans to the motion range of the piezo positioners which is typically a few tens of microns. To bridge this experimental gap, the study proposes a long-range SECCM system with a rapid gas-exchange environmental cell for high-throughput electrochemical characterization of 100 mm diameter HEA thin-film material libraries (ML) obtained by combinatorial co-sputtering. Due to the gas-liquid interface at the positioned SECCM droplet on the sample, high-throughput evaluation under industrial current density conditions becomes feasible. This allows the direct correlation between electrocatalytic activity and material composition with high statistical reliability. The multidimensional data obtained accelerates materials discovery, development, and optimization.

14.
Inorg Chem ; 63(1): 537-547, 2024 Jan 08.
Article in English | MEDLINE | ID: mdl-38108625

ABSTRACT

In this article, we discuss the synthesis of eight novel zirconium and hafnium complexes containing amidoxime ligands as potential precursors for atomic layer deposition (ALD). Two amidoximes, viz., (E)-N'-hydroxy-N,N-dimethylacetimidamide (mdaoH) and (Z)-N'-hydroxy-N,N-dimethylpivalimidamide (tdaoH), along with their Zr and Hf homoleptic complexes, Zr(mdao)4 (1), Hf(mdao)4 (2), Zr(tdao)4 (3), and Hf(tdao)4 (4) were prepared. We further synthesized heteroleptic compounds with different physical properties by introducing cyclopentadienyl (Cp) ligand, namely, CpZr(mdao)3 (5), CpHf(mdao)3 (6), CpZr(tdao)3 (7), and CpHf(tdao)3 (8). Thermogravimetric analysis was used for the assessment of the evaporation characteristics of complexes 1, 2, 5, and 6, and it revealed multistep weight losses with high residues. On the other hand, the thermogravimetric analysis curves of complexes 3, 4, 7, and 8 comprising tdao ligands revealed single-step weight losses with moderate residues. Single-crystal X-ray diffraction studies of complexes 1, 3, and 7 showed that all of the complexes have monomeric molecular structures. Complex 7 exhibited a low melting point (75 °C), good volatility, and high thermal stability compared with other complexes. Therefore, an atomic layer deposition process for the growth of ZrO2 was developed by using ZrCp(tdao)3 (7) as a novel precursor.

15.
Org Lett ; 26(1): 198-203, 2024 Jan 12.
Article in English | MEDLINE | ID: mdl-38153405

ABSTRACT

A practical method for C(sp3)-B bond activation was developed. Using a combination of alkyl trifluoroborates and N-iodosuccinimide (NIS), various C(sp3)-heteroatom bonds were readily generated in an efficient manner. Mechanistic studies revealed the bifunctional ability of NIS: mediating the formation of reactive halogenated intermediates and activating them via halogen bonding. This electrophilic activation of the reaction center enables the utilization of general heteroatom nucleophiles, which are used in a limited capacity in traditional 1,2-metalate rearrangements.

16.
ACS Omega ; 8(46): 43759-43770, 2023 Nov 21.
Article in English | MEDLINE | ID: mdl-38027341

ABSTRACT

This study describes the synthesis of 12 new germanium complexes containing ß-diketonate and/or N-alkoxy carboxamidate-type ligands as precursors for GeO2 through atomic layer deposition (ALD). A series of Ge(ß-diketonate)Cl complexes such as Ge(acac)Cl (1) and Ge(tmhd)Cl (2) were synthesized by using acetylacetone (acacH) and 2,2,6,6-tetramethyl-3,5-heptanedione (tmhdH). N-Alkoxy carboxamidate-type ligands such as N-methoxypropanamide (mpaH), N-methoxy-2,2-dimethylpropanamide (mdpaH), N-ethoxy-2-methylpropanamide (empaH), N-ethoxy-2,2-dimethylpropanamide (edpaH), and N-methoxybenzamide (mbaH) were used to afford further substituted complexes Ge(acac)(mpa) (3), Ge(acac)(mdpa) (4), Ge(acac)(empa) (5), Ge(acac)(edpa) (6), Ge(acac)(mba) (7), Ge(tmhd)(mpa) (8), Ge(tmhd)(mdpa) (9), Ge(tmhd)(empa) (10), Ge(tmhd)(edpa) (11), and Ge(tmhd)(mba) (12), respectively. Thermogravimetric analysis curves, which mostly exhibited single-step weight losses, were used to determine the evaporation properties of complexes 1-12. Interestingly, liquid complex 2 has no residue at 198 °C and therefore exhibits excellent vaporization properties and high volatility. Single-crystal X-ray diffraction studies of 1 and 7 demonstrated that the complexes had monomeric molecular structures with germanium chelated by the oxygen atoms of one or two bidentate ligands, respectively. An ALD process was developed for the growth of GeO2 using Ge(tmhd)Cl (2) as a new precursor and H2O2 as an oxidant. This study demonstrates the achievement of self-limiting growth of GeO2 films by varying the duration of injection/purge, with an observed ALD window at deposition temperatures ranging from 300 to 350 °C. The saturated growth per cycle of the GeO2 film was determined as 0.27 Å/cycle at a deposition temperature of 300 °C. The deposited films were observed to be amorphous consisting of GeO2.

17.
Dalton Trans ; 52(41): 15033-15042, 2023 Oct 24.
Article in English | MEDLINE | ID: mdl-37812132

ABSTRACT

Novel Sn precursors, Sn(tbip)2, Sn(tbtp)2, and Sn(tbta)2, were synthesized and characterized using various analytical techniques and density functional theory calculations. These precursors contained cyclic amine ligands derived from iminopyrrolidine. X-ray crystallography revealed the formation of monomeric SnL2 with distorted seesaw geometry. Thermogravimetric analysis demonstrated the exceptional volatility of all complexes. Sn(tbtp)2 showed the lowest residual weight of 2.7% at 265 °C. Sn3N4 thin films were successfully synthesized using Sn(tbtp)2 as the Sn precursor and NH3 plasma. The precursor exhibited ideal characteristics for atomic layer deposition, with a saturated growth per cycle value of 1.9 Å cy-1 and no need for incubation when the film was deposited at 150-225 °C. The indirect optical bandgap of the Sn3N4 film was approximately 1-1.2 eV, as determined through ultraviolet-visible spectroscopy. Therefore, this study suggests that the Sn3N4 thin films prepared using the newly synthesized Sn precursor are suitable for application in thin-film photovoltaic devices.

18.
Angew Chem Int Ed Engl ; 62(39): e202310069, 2023 Sep 25.
Article in English | MEDLINE | ID: mdl-37537136

ABSTRACT

The vast possibilities in the elemental combinations of high-entropy alloys (HEAs) make it essential to discover activity descriptors for establishing rational electrocatalyst design principles. Despite the increasing attention on the potential of zero charge (PZC) of hydrogen evolution reaction (HER) electrocatalyst, neither the PZC of HEAs nor the impact of the PZC on the HER activity at HEAs has been described. Here, we use scanning electrochemical cell microscopy (SECCM) to determine the PZC and the HER activities of various elemental compositions of a Pt-Pd-Ru-Ir-Ag thin-film HEA materials library (HEA-ML) with high statistical reliability. Interestingly, the PZC of Pt-Pd-Ru-Ir-Ag is linearly correlated with its composition-weighted average work function. The HER current density in acidic media positively correlates with the PZC, which can be explained by the preconcentration of H+ in the electrical double layer at potentials negative of the PZC.

19.
ACS Omega ; 8(25): 22783-22787, 2023 Jun 27.
Article in English | MEDLINE | ID: mdl-37396266

ABSTRACT

Novel barium heteroleptic complexes were synthesized through the substitution of the bis(trimethylsilyl)amide of Ba(btsa)2·2DME with aminoalkoxide and ß-diketonate ligands. Compounds [Ba(ddemap)(tmhd)]2 (1) and [Ba(ddemmp)(tmhd)]2 (2) were obtained and analyzed through Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and elemental analysis (ddemapH = 1-(dimethylamino)-5-((2-(dimethylamino)ethyl) (methyl)amino)pentan-3-ol and ddemmpH = 1-(dimethylamino)-5-((2-(dimethylamino)ethyl) (methyl)amino)-3-methylpentan-3-ol). In single-crystal X-ray crystallography, complex 1 exhibited a dimeric structure with µ2-O bonds of the ddemap ligand. All complexes exhibited high volatility and could be sublimed under reduced pressure (0.5 Torr) at 160 °C, indicating that these complexes are promising candidates as atomic layer deposition or chemical vapor deposition precursors for the growth of barium-containing thin films.

20.
Biosens Bioelectron ; 237: 115518, 2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37442029

ABSTRACT

Viruses have unique coat proteins that are genetically modifiable. Their surface can serve as a nano-template on which electroactive molecules are immobilized. In this study, we report filamentous bacteriophage as a backbone to which redox mediators are covalently and densely tethered, constructing redox nanowire, i.e. an electron conducting biomaterial. The highly ordered coat proteins of a filamentous bacteriophage provide flexible and biocompatible platform to constitute a biohybrid redox nanowire. Incorporating bacteriophage and redox molecules form an entangled assembly of nanowires enabling facile electron transfer. Electron transfer among the molecular mediators in the entangled assembly originates apparent electron diffusion of which the electron transfer rate is comparable to that observed in conventional redox polymers. Programming peptide terminals suggests further enhancement in electron mediation by increasing redox species mobility. In addition, the redox nanowire film functions as a favorable matrix for enzyme encapsulation. The stability of the enzymes entrapped in this unique matrix is substantially improved.


Subject(s)
Bacteriophages , Biosensing Techniques , Nanowires , Nanowires/chemistry , Oxidation-Reduction , Electron Transport , Electrodes
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