Distribution Of Sites Research Articles

Enhanced CO2 methanation activity over Ni/CeO2 catalyst by adjusting metal-support interactions

CO2 methanation is an essential means of utilizing CO2, which is crucial to solving environmental problems and alleviating energy crisis. The design and development of high- performance low temperature CO2 methanation catalysts is the key to its further application. In this work, the metal-support interaction of Ni/CeO2 catalyst was regulated by changing the calcination temperature and Ni loadings to optimize the CO2 methanation performance. The results showed that 5NiCe-800 exhibited the best CO2 conversion of 83.1 % and 98.0 % CH4 selectivity at 350 °C, since it has a suitable Ni-CeO2 interaction, higher oxygen vacancy concentration, great reducibility and better basic site distribution. The reaction mechanism and the synergistic effect of CeO2 and Ni in CO2 methanation was revealed by in-situ FTIR, which is of great significance for the development of efficient CeO2 supported Ni-based for CO2 methanation.

Distinct structure-activity relationship and reaction mechanism over BaCoO3/CeO2 catalysts for NO direct decomposition

The dependency on morphology is crucial for achieving highly efficient direct decomposition of NO. Herein, a BaCoO3/CeO2 catalyst is synthesized using CeO2 small particles (p), spheres (s) and rods (r) as supports. The NO conversion to N2 (NTN2) at 800 °C follows the order BaCoO3/CeO2-r (78.8 %) > BaCoO3/CeO2-s (75.9 %) > BaCoO3/CeO2-p (56.9 %) > BaCoO3 (8.6 %) at a space velocity 1 g s/cm3. BaCoO3/CeO2-r exhibts high tolerance to O2 and stability with conversion decreasing from 78.8 % to 74.6 %, 60.0 % and 50.0 % at 800 °C with 1, 5 and 10 vol% O2, respectively. The high redox activity, higher active oxygen mobility and NO adsorption capability ensures its superior performance, while the high surface area (31.29 m2/g) and uniform distribution of active sites on the surface further promote the activity. The mechanism of NO direct decomposition is elucidated by in situ Diffuse reflectance infrared Fourier transform spectroscopy, 18O2 isotopic transient exchange experiments and density functional theory (DFT) calculation.

Vascular Reactivity Index as an Effective Predictor of Mortality in Patients With Septic Shock: A Retrospective Study.

Sepsis is a serious complication that occurs after trauma, burns, and infections, and it is an important cause of death in intensive care unit (ICU) patients. Despite many new measures being proposed for sepsis treatment, its mortality rate remains high; sepsis has become a serious threat to human health, and there is an urgent need to carry out in-depth clinical research related to sepsis. In recent years, it has been found that septic shock-induced vasoplegia is a result of vascular hyporesponsiveness to vasopressors. Therefore, this study intended to establish an objective formula related to vasoplegia that can be used to assess the prognosis of patients and guide clinical treatment. A retrospective cohort study was conducted using data from 106 septic shock patients admitted to the ICU of Jining No. 1 People's Hospital from January 2020 to December 2022. The patients were divided into mortality and survival groups based on 28-day survival, and hemodynamics were monitored by the pulse index continuous cardiac output system. The dose and duration of vasopressors, major hemodynamic parameters, lactic acid (Lac) levels, and Sequential Organ Failure Assessment scores were recorded within 48 h of hospital admission. Multifactorial logistic regression was used to analyze the independent risk factors affecting the prognosis of patients, and the predictive value of the vascular response index (VRI) was analyzed by the receiver operating characteristic (ROC) curve. The differences between the survival and mortality groups in terms of age, sex ratio, body weight, ICU length of stay, distribution of infection sites, underlying disease conditions, baseline Lac levels, and some hemodynamic parameters were not statistically significant (P > .05). The results of multifactorial logistic regression showed that the admission Acute Physiology and Chronic Health Evaluation II score, Lac level at 24 h of treatment, maximal vasoactive inotropic score at 24 h (VISmax24), maximal vasoactive inotropic score at 48 h (VISmax48), and VRI were independent risk factors affecting 28-day mortality. Within 48 h of receiving vasopressor therapy, the VRI was lower in the mortality group than in the survival group. The area under the ROC curve for the VRI was 0.86, and the best cutoff value of the VRI for predicting 28-day mortality was 32.50 (YI = 0.80), with a sensitivity of 0.90, a specificity of 0.90, and a better prediction of mortality than the other indicators. The VRI is a good predictor of mortality in patients with septic shock, and a lower VRI indicates more severe vasoplegia, poorer prognosis, and higher mortality in patients with septic shock.

There and back again? A B cell’s tale on responses and spatial distribution in teleosts

Teleost B cells are of special interest due to their evolutionary position and involvement in vaccine-induced adaptive immune responses. While recent progress has revealed uneven distribution of B cell subsets across the various immune sites and that B cells are one of the early responders to infection, substantial knowledge gaps persist regarding their immunophenotypic profile, functional mechanisms, and what factors lead them to occupy different immune niches. This review aims to assess the current understanding of B cell diversity, their spatial distribution in various systemic and peripheral immune sites, how B cell responses initiate, the sites where these responses develop, their trafficking, and the locations where long-term B cell responses take place.

Geohydrologic units of Ischia Island (Southern Tyrrhenian Sea, Italy)

ABSTRACT The first hydrogeological mapping of Ischia Island at the 1:10,000 scale is presented and discussed. The ‘Map of the geohydrologic units of Ischia Island’ and the accompanying hydrostratigraphic sequence at a basin scale are based on the most recent geological maps and data from the CAR.G Project, and on new volcanological and hydrogeological surveys and studies. Data sources include the database stored by the INGV, Sezione di Napoli, Osservatorio Vesuviano and field investigations, including a survey of the springs and thermo-mineral springs which has been neglected up to now. In total 130 volcanostratigraphic units and 18 geohydrologic units were recognized; the distribution of fumaroles sites was enhanced, and 60 springs/thermal springs were identified/rediscovered. The proposed hydrogeological map provides an overview of the volcano-tectonic evolution of Ischia Island and upgrades the hydrogeological model, becoming a catalyst for the effort to acquire better data and to manage natural both resources and risks.

Coordination‐mediated atomic metal catalysts for cascaded transformation of β‐O‐4 dimeric model compound into quinoline

AbstractHere, we report the fabrication of atomic‐metal catalysts for the facile cascaded transformation of lignin β‐O‐4 dimeric model compound into quinoline. A series of dual‐metal single‐atom (SA) moieties (MaC4 and Mb2N6, where Ma and Mb represent two different metal SAs, C and N represent carbon and nitrogen atoms, respectively) are integrated on N‐doped carbons with designed compositions and coordination configurations. Characterizations indicate the homogeneous distribution of uniform and modifiable SA sites, over which the electron distribution is significantly polarized due to synergistic interactions. The distinctive physicochemical properties of catalysts afford attractive performances in the cascaded synthesis of quinoline from lignin β‐O‐4 dimeric model compound through cascaded transformation. In a continuous flow instrument, CuC4/Co2N6@NC furnishes 93.7% yield of 2‐phenylquinoline with a space‐time yield of 75.7 g gcat h−1. Control experiments and density functional theory calculations reveal the synergistic interactions between CuC4 and Co2N6 endow the catalyst with high efficiency in cascaded transformation.

Discovering High Entropy Alloy Electrocatalysts in Vast Composition Spaces with Multiobjective Optimization.

High entropy alloys (HEAs) are a highly promising class of materials for electrocatalysis as their unique active site distributions break the scaling relations that limit the activity of conventional transition metal catalysts. Existing Bayesian optimization (BO)-based virtual screening approaches focus on catalytic activity as the sole objective and correspondingly tend to identify promising materials that are unlikely to be entropically stabilized. Here, we overcome this limitation with a multiobjective BO framework for HEAs that simultaneously targets activity, cost-effectiveness, and entropic stabilization. With diversity-guided batch selection further boosting its data efficiency, the framework readily identifies numerous promising candidates for the oxygen reduction reaction that strike the balance between all three objectives in hitherto unchartered HEA design spaces comprising up to 10 elements.

Determinant of m6A regional preference by transcriptional dynamics.

N6-Methyladenosine (m6A) is the most abundant chemical modification occurring on eukaryotic mRNAs, and has been reported to be involved in almost all stages of mRNA metabolism. The distribution of m6A sites is notably asymmetric along mRNAs, with a strong preference toward the 3' terminus of the transcript. How m6A regional preference is shaped remains incompletely understood. In this study, by performing m6A-seq on chromatin-associated RNAs, we found that m6A regional preference arises during transcription. Nucleosome occupancy is remarkedly increased in the region downstream of m6A sites, suggesting an intricate interplay between m6A methylation and nucleosome-mediated transcriptional dynamics. Notably, we found a remarkable slowdown of Pol-II movement around m6A sites. In addition, inhibiting Pol-II movement increases nearby m6A methylation levels. By analyzing massively parallel assays for m6A, we found that RNA secondary structures inhibit m6A methylation. Remarkably, the m6A sites associated with Pol-II pausing tend to be embedded within RNA secondary structures. These results suggest that Pol-II pausing could affect the accessibility of m6A motifs to the methyltransferase complex and subsequent m6A methylation by mediating RNA secondary structure. Overall, our study reveals a crucial role of transcriptional dynamics in the formation of m6A regional preference.

Tailoring the Active Species Distribution of Heterogeneous Catalyst for Regulating the Chain Structure of Nascent Polyethylene

AbstractHeterogeneous catalysis is the most widely used process for ethylene polymerization in industry. Active site distribution is one of the crucial issues in the heterogeneous catalysis, which strongly influences the catalytic process and the microstructure of synthesized polyethylene. In this respect, aiming at an explicit understanding of the progress, the challenge and the possible future directions in the study of heterogeneous catalysis of ethylene polymerization, the recent strategies of designing heterogeneous catalysts are reviewed from the perspective of tailoring the active site distribution, where the regulation of chain structures, including molecular weight distribution, branch distribution and entanglement state, are highlighted. The in situ and operando characterizations are also reviewed for assisting the understanding of structural information in heterogeneous catalysts.

Promoted catalytic performance of sugarcane bagasse ash supported by γ‐alumina as efficient, stable, and ecofriendly catalyst for dehydration of methanol to dimethyl ether

AbstractThe aim of this study was to use different proportions (1% to 20% by weight) of γ‐alumina to modify sugarcane bagasse ash (SCBA) for the production of dimethyl ether (DME) through the dehydration of methyl alcohol. A simple precipitation method was utilized to fabricate (1–20 wt.%) Al2O3/SCBA catalysts. X‐ray fluorescence, X‐ray diffraction, Fourier‐transform infrared spectroscopy, transmission electron microscopy, and N2 sorption were used to explore the structural, spectroscopic, morphological, and textural features. The XRD pattern of Al2O3/SCBA catalysts showed a new peak that corresponded to the formation of γ‐Al2O3. In addition, the average crystallite sizes of pure SCBA and 10% and 20%Al2O3/SCBA catalysts were calculated and found to be 20.1, 21.6, and 22.6 nm, respectively. To evaluate the acidity of these catalysts, the dehydration of isopropyl alcohol and the chemisorption of basic probe molecules were employed. The acidity test results displayed that these catalysts have weak to moderate acidic sites. The 10% Al2O3/SCBA catalyst calcined at 400°C showed high efficiency for the conversion of methyl alcohol to DME, attaining 89% conversion with 100% selectivity. This observation can be attributed to the even distribution of active sites and the acid–base equilibrium on the surface. Moreover, its catalytic activity and selectivity remain unchanged over a continuous 2‐week operation without coke formation, demonstrating its extremely high stability. A strong correlation was observed between the catalytic activity and both the surface area and acidity of the catalysts.

Chromosome-Scale Genome Assembly for Clubrush (Bolboschoenus planiculmis) Indicates a Karyotype with High Chromosome Number and Heterogeneous Centromere Distribution.

Bolboschoenus planiculmis (F.Schmidt) T.V.Egorova is a typical wetland plant in the species-rich Cyperaceae family. This species contributes prominently to carbon dynamics and trophic integration in wetland ecosystems. Previous studies have reported that the chromosomes of B. planiculmis are holocentric; i.e. they have kinetic activity along their entire length and carry multiple centromeres. This feature was suggested to lead to a rapid genome evolution through chromosomal fissions and fusions and participate to the diversification and ecological success of the Bolboschoenus genus. However, the specific mechanism remains uncertain, partly due to the scarcity of genetic information on Bolboschoenus. We present here the first chromosome-level genome assembly for B. planiculmis. Through the integration of high-quality long-read and short-read data, together with chromatin conformation using Hi-C technology, the ultimate genome assembly was 238.01 Mb with a contig N50 value of 3.61 Mb. Repetitive elements constituted 37.04% of the genome, and 18,760 protein-coding genes were predicted. The low proportion of long terminal repeat retrotransposons (∼9.62%) was similar to that reported for other Cyperaceae species. The Ks (synonymous substitutions per synonymous site) distribution suggested no recent large-scale genome duplication in this genome. The haploid assembly contained a large number of 54 pseudochromosomes with a small mean size of 4.10 Mb, covering most of the karyotype. The results of centromere detection support that not all the chromosomes in B. planiculmis have multiple centromeres, indicating more efforts are needed to fully reveal the specific style of holocentricity in cyperids and its evolutionary significance.

Tuning the luminescence color of Eu3+- and alkali-ion-codoped Sr2CaWO6 orange-red phosphors: Eu3+ site distribution and site-selective photoluminescence studies

In this study, Eu3+- and alkali-ion (M+)-codoped Sr2CaWO6:x (Eu3+, M+) (x = 0.01–0.10) were synthesized via a solid-state reaction. The effects of different Sr/Ca ratios, types of monovalent metal ions (M+ = Na+, K+, and Li+), and doping concentrations were systematically investigated. The crystalline phase, photoluminescence (PL) properties, lattice site occupied by the Eu3+ ion, Eu3+ site distribution, and site-selective PL properties were evaluated by x-ray diffraction, PL/photoluminescence excitation (PLE) spectroscopy with a monochromatic light source, PL quantum efficiency (QE) measurements, and high-resolution PL/PLE spectroscopy with a wavelength-tunable laser. A dependence of the PL asymmetry ratio for the 5D0–7F1,2 transitions on the Sr/Ca ratio was identified and quantified for the first time. Based on the site-selective PL measurements, this behavior was ascribed to the enhancement of Eu3+ local distortion by Sr2+ substitution at the A site at lower Sr/Ca ratios (<2) and to the high symmetry of the ligand structure of EuO6 octahedra owing to Ca2+ substitution at the B site at higher Sr/Ca ratios (>2). The PLE results provided insight into the Eu3+ site distribution, which explained the orange-red PL and PL QEs of the synthesized phosphors.

The Suitability of Fe3O4/Graphene Oxide Nanocomposite for Adsorptive Removal of Methylene Blue and Congo Red

In this study, Fe3O4/GO nanocomposite was synthesized by hydrothermal method and tested for its efficiency in removing methylene blue (MB) and congo red (CR) from water. The synthesized nanocomposite was characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The optimal values for MB and CR removal were determined to be pH 6.0, an adsorbent weight of 50.0 mg, and a contact time of 10 min. The adsorption isotherms of the contaminants on the nanocomposite were analyzed using the Freundlich model, indicating a heterogeneous distribution of active sites on the adsorbent surface. The highest adsorption capacity of MB and CR is 135.1 and 285.7 mg.g-1, respectively. Moreover, Fe3O4/GO nanocomposite recycled five cycles with proper adsorption capacity. Overall, the Fe3O4/GO nanocomposite holds great promise for efficient and sustainable water treatment, providing safe and clean water globally.

Comprehensive risk assessment of a renewables‐based stand‐alone electric vehicle charging station with multiple energy storage technologies

AbstractThis study presents the application of a comprehensive risk assessment and risk management framework on a grid‐independent and renewable energy‐based electric vehicle charging station with multiple energy storage techniques including hydrogen and ammonia. The design comprises complex subsystems such as concentrated photovoltaic thermal, wind turbine, biomass standby generator, hydrogen storage, fuel cell, Ammonia storage and fuel cell, Lithium‐ion battery storage, Salt‐hydrate thermal storage, lithium‐bromide absorption cooling, and fast charging units. Systematic risk‐based approaches compromising multiple phases and qualitative and quantitative risk assessment techniques are applied to identify the causes and consequences of potentially critical events associated with the incorporated subsystems and components. The results show that out of 15 identified technical, economic, environmental, and health and safety risks, three health and safety risks were found unacceptable with risk values above 14. In contrast, three technical, three environmental, two health and safety, and one economic risks were found undesirable with risk values between 8 and 12. Appropriate preventive and protective measures are applied to lessen the high‐risk levels to acceptable safe limits below 6. Proper safety barriers and distances are considered while recommending the associated subsystems and components' optimal physical site distribution plan.

Heterostructures by Templated Synthesis of Layered Double Hydroxide to Modulate the Electronic Structure of Nickel Sites for a Highly Efficient Oxygen Evolution Reaction

The design and development of highly efficient electrocatalysts for oxygen evolution reaction (OER) are critical for renewable energy generation. Ni‐based electrocatalysts are widely used in the water electrolysis process. In this work, heterostructure consisting of selenides and layered double hydroxides (LDH) named (Co, Ni)Se4@NiFe‐LDH, are prepared by an LDH‐based strategy, in which the electronic structure of Ni active sites is regulated by interfacial electron interaction. The (Co, Ni)Se4@NiFe‐LDH shows an optimized charge distribution of Ni sites and excellent catalytic activity. The effective charge modulation results in lowering the energy barrier of OOH* intermediate formation and adequate adsorption strength of the intermediates on Ni‐active sites, which improves the kinetics of OER. Specifically, the (Co, Ni)Se4@NiFe‐LDH only requires an overpotential of 237 mV to reach the current density of 10 mA cm−2 under alkaline conditions. The results of this work demonstrate that reasonable engineering of heterostructure is an effective strategy to improve the intrinsic property of OER electrocatalysts for water splitting.

A layered multifunctional framework based on polyacrylonitrile and MOF derivatives for stable lithium metal anode

Composite Li metal anodes based on three-dimensional (3D) porous frameworks have been considered as an effective material for achieving stable Li metal batteries with high energy density. However, uneven Li deposition behavior still occurs at the top of 3D frameworks owing to the local accumulation of Li ions. To promote uniform Li deposition without top dendrite growth, herein, a layered multifunctional framework based on oxidation-treated polyacrylonitrile (OPAN) and metal-organic framework (MOF) derivatives was proposed for rationally regulating the distribution of Li ions flux, nucleation sites, and electrical conductivity. Profiting from these merits, the OPAN/carbon nano fiber-MOF (CMOF) composite framework demonstrated a reversible Li plating/stripping behavior for 500 cycles with a stable Coulombic efficiency of around 99.0% at the current density of 2 mA/cm2. Besides, such a Li composite anode exhibited a superior cycle lifespan of over 1300 h under a low polarized voltage of 18 mV in symmetrical cells. When the Li composite anode was paired with LiFePO4 (LFP) cathode, the obtained full cell exhibited a stable cycling over 500 cycles. Moreover, the COMSOL Multiphysics simulation was conducted to reveal the effects on homogeneous Li ions distribution derived from the above-mentioned OPAN/CMOF framework and electrical insulation/conduction design. These electrochemical and simulated results shed light on the difficulties of designing stable and safe Li metal anode via optimizing the 3D frameworks.

Regulating the distribution of iron active sites on γ-Fe2O3via Mn-modified α-Fe2O3 for NH3-SCR

Developing below 150 °C highly activity and broad reaction window catalysts has been challenging by using Fe-based catalysts for NH3-SCR. The octahedral Fe3+ (Fe3+Oh) sites exist in hematite (α-Fe2O3) and maghemite (γ-Fe2O3) are inactive for NH3-SCR due to the redox circle of Fe2+→Fe3+ reliance on the distribution of iron sites in crystal structure. Here we modified the α-Fe2O3 crystal structure by substituting part inactive Fe3+Oh sites with catalytically active Mn3+Oh sites, which promoted the formation of γ-Fe2O3 to generate the active tetrahedral Fe3+ (Fe3+Td) sites and enhanced the magnetism of the Fe1−yMnyOx. The strong Fe-O-Mn interaction established by crystal coordinative configurations not only boosted the formation of NO2 but also facilitated the Brønsted acid circle. Surprisingly, the Fe0.85Mn0.15Ox exhibited the superior low temperature NH3-SCR activity, with NOx conversion above 100% at 100–275 °C under a GHSV of 60000 h−1.

Demographic and clinical profile of 1106 adult soft tissue sarcoma patients: A single institutional prospective database experience from India.

Adult soft tissue sarcomas (STS) are rare and diverse. Current management is based on limited literature from the West. Therefore, data from different geographical regions is required, including the low-middle-income countries. This is our experience managing adult sarcomas in the tertiary cancer center of North India. This is a retrospective analysis of the structured sarcoma database of patients treated in the surgical oncology department between 1992 and 2020. The descriptive analysis includes demography, site distribution, diagnosis, histopathology variations, prior surgical interventions, and stage. A total of 1106 soft tissue sarcoma patients were treated in three decades. Age distribution was 13%, 43%, 31%, and 11% in <20, 21-40, and 41-60 and >60 years, respectively. The male-to-female ratio was 1.73. The anatomical distribution was 17%, 42%, 23%, 7%, 7%, and 3% in upper extremity, lower extremity, trunk, retroperitoneum, head and neck, and viscera, respectively. Overall, 49% of patients had undergone prior suboptimal surgeries at community hospitals. Common histology subtypes were synovial sarcoma (18%), undifferentiated pleomorphic sarcoma (UPS) (13%), dermatofibrosarcoma protuberans (12%), and liposarcoma (9%). A pathological discordance of 13% was identified between the initial and the final histologies. Overall, 61% of tumors were high-grade. Memorial Sloan Kettering Stages II and III were present in 33% and 35% of patients, respectively. This is one of the largest single institutional experiences of STS from the Asian population. Mostly young adults were affected with male preponderance. The lower extremity and trunk were common subsites. Frequent histologies were synovial sarcoma and UPS. A high rate of suboptimal surgical intervention at the community level and pathological discordance was noted. This study highlights the need to establish prospective structured databases for capturing quality information related to rare malignancies and providing insights for future research.

The Occurrence of Suids in the Post-Olduvai to Pre-Jaramillo Pleistocene of Europe and Implications for Late Villafranchian Biochronology and Faunal Dynamics

It has been proposed that suids were absent from Europe during the post-Olduvai to pre-Jaramillo Early Pleistocene (from less than 1.8 to more than 1.2 Ma) and that their “re-appearance” in the late Early Pleistocene would mark the end of the late Villafranchian and the beginning of the Epivillafranchian. Arguments enumerated in favor of this “suid gap” are the lack of suid remains from extensively sampled fossil localities of this age and the high reproductive potential (r-strategy) of suids, which would translate in a high commonness of their remains in the fossil record. However, here it shown that while suids’ reproductive potential is certainly exceptional within artiodactyls, there is no direct relationship between the reproductive strategy and preservation rate of a taxon in the fossil record. In Early Pleistocene localities of Europe and adjoining areas, where suids are present in a fossil assemblage, they are always rare. In terms of number of occurrences (frequency), suids range from being moderately common (~2.0–1.8 Ma) to moderately rare (~1.1–1.0 Ma). Suid material is also described herein from Peyrolles (Issoire, France; reference locality for MNQ 19), a site dated at 1.47 Ma, providing direct evidence for the presence of suids within the purported “suid gap”. The case of suids underlines an important source of caveat in inferring faunal dynamics of the late Early Pleistocene of western Europe—including the dispersal of hominins—i.e., the unequal geographical distribution of the paleontological sites of post-Olduvai to pre-Jaramillo age. Indeed, Peyrolles is the only large mammal site in western Europe located outside the Iberian and Italian Peninsulas reliably dated around 1.5 Ma. In the post-Olduvai to pre-Jaramillo period, there is a paucity of radiometric estimates (or they have too coarse a resolution) and of paleomagnetic excursions detectable in continental deposits. Basically, for this time span, there is a high dependence on biochronological correlations, although, at the same time, these correlations are less reliable—because these are based on a few sites not covering the entire spectrum of environments present in Europe and the sites are not independently dated with methods that outperform biochronology—than those for other periods.

Chiral Aldehyde Catalysis-Enabled Asymmetric α-Functionalization of Activated Primary Amines.

ConspectusThe development of catalytic activation modes provides a reliable and effective platform for designing new enantioselective reactions and preparing chiral molecules with diverse structures. Chiral aldehyde catalysis is an attractive concept in asymmetric catalysis, which utilizes a chiral aldehyde catalyst to promote the asymmetric hydroamination of allylic amines, the asymmetric α-functionalization of primary amines, or the asymmetric transamination of α-keto esters. Typically, the chiral aldehyde-catalyzed asymmetric α-functionalization of primary amines provides an efficient and straightforward method for the synthesis of α-functionalized chiral amines, which does not require any additional protection or deprotection manipulations of the amine group. However, achieving catalytic stereoselective transformations with high efficiency and enantioselectivity by this strategy has remained an intractable challenge.This Account summarizes our endeavors in the development and application of chiral aldehyde catalysis. Using a chiral aldehyde as a catalyst, we reported the catalytic asymmetric α-C alkylation of 2-aminomalonate with 3-indolylmethanol in 2014, which represents the first chiral aldehyde-catalyzed asymmetric α-functionalization of an activated primary amine. Subsequently, several axially chiral aldehyde catalysts were continuously prepared by using chiral BINOL as the starting material, and their applications in asymmetric synthesis were explored. On the one hand, they were used as organocatalysts to realize the various transformations of α-amino acid esters, such as asymmetric 1,4-addition toward conjugated enones/α,β-unsaturated diesters and cyclic 1-azadienes as well as asymmetric α-arylation/allylation and benzylation with corresponding halohydrocarbons. Notably, taking advantage of the difference in the distribution of catalytic sites between two chiral aldehyde catalysts, we disclosed chiral aldehyde-catalyzed diastereodivergent 1,6-conjugated addition and Mannich reactions. On the other hand, the potential for the cooperative catalysis of a chiral aldehyde with a transition metal has also been demonstrated. Enabled by the combination of a chiral aldehyde, a palladium complex, and a Lewis acid, the enantioselective α-allylation of amino acid esters with allyl alcohol esters was established. Moreover, the ternary catalytic system has been successfully used for the α-functionalization of amino acid esters with 1,3-dienes, allenes, allenylic alcohol esters, 1,3-disubstituted allyl alcohol esters, and arylmethanol esters as well as the asymmetric cascade Heck-alkylation reaction. The combination of a chiral aldehyde and nickel complex allows for the asymmetric α-propargylation of amino acid esters with propargylic alcohol esters and provides excellent enantioselectivities. These transformations provide a large library of optically active amines and amino acids. With those chiral amino acid esters as key building blocks, the synthesis or formal synthesis of multiple natural products and biologically significant unnatural molecules was accomplished. This includes the stereodivergent synthesis of natural pyrrolizidine alkaloid NP25302 and the formal synthesis of natural product (S)-hypoestestatin 1 and manzacidin C, clinical candidate compound (+)-AG-041R, and somatostatin mimetics. It is fully anticipated that chiral aldehyde catalysis will soon witness rapid expansion both in the development of novel asymmetric transformations and in innovative applications for constructing optically active nitrogen-containing molecules with significant values.