Structural Defects Research Articles

Engineering the structure defects of ceria-zirconia-praseodymia solid solutions for diesel soot catalytic elimination

Creating structure defects in ceria-based solid solution catalysts is a crucial yet challenging task. Herein, urea-assisted synthesis strategy was designed for ceria-zirconia-praseodymia catalyst (CeZrPrOx) to create lattice defects; its effects on catalyst structure, physical-chemical properties and catalytic diesel soot purification activity were systematically investigated. Raman and X-ray photoelectron spectroscopy (XPS) findings indicate that the urea-assisted synthesized catalyst (CeZrPrOx-U) has remarkably more Ce3+ proportion (structure defects), oxygen vacancies and surface reactive oxygen species (O22- and O2-). Temperature-programmed reduction by hydrogen (H2-TPR) and temperature-programmed desorption by oxygen (O2-TPD) results further prove that the oxygen migration of the CeZrPrOx-U is definitely enhanced. Compared to the conventional CeZrPrOx catalyst, the bulk lattice oxygen of the CeZrPrOx-U can be migrated to the surface to generate surface reactive oxygen species more easily. As a consequence, the prepared CeZrPrOx-U catalyst exhibits obviously better catalytic diesel soot purification activity. Therefore, this study suggests that engineering the structure defects in CeZrPrOx catalyst is an effective approach to improve physical-chemical properties and enhance the soot catalytic elimination activity of the catalyst.

Room temperature oxygenated groups addition in carbon materials via ozone oxidation for boosting electrochemical H2O2 production

The crucial yet delicate 2e− oxygen reduction reaction (ORR) for producing the green chemical H2O2 relies on the uniform coordination environment of the active sites, such as oxygenated groups in metal-free carbon material catalysts. However, conventional harsh carbon material synthesis methods inevitably introduce structural defects and alter morphology, hindering the precise control of active site formation. Herein, we developed the ozone oxidation method under controlled reaction conditions to precisely modify carbon materials at room temperature. Through controlling the ozonation of reaction time, concentration, temperature, and relative humidity, we find the mild method allows us to precisely add active carboxyl group (–COOH) without forming structural defects. Electrochemical tests reveal that the optimal catalyst with the highest –COOH content exhibits the most outstanding mass activity of 164 A/g at 0.65 V and the highest H2O2 selectivity of 91 %. The density functional theory calculations demonstrate that the carbon sites directly connected to –COOH possess the optimized binding strength of *OOH intermediate to favor the two-electron oxygen reduction process. This work offers a novel approach to precisely and gently control carbon surface groups while preserving the structural morphology through ozone gas treatment, which can be readily applied to other material designs.

Evaluation of Applied Destructive and Non-destructive Tests in the Technical Inspection Process of High-Frequency Electric Resistance Weld Pipes

Ensuring the absence of structural defects in metal pipes of the gas network requires production control and quality control tests. On the other hand, the main role of these pipes is the transmission of natural gas, therefore, the smallest leakage, along with damage to the environment and loss of natural gas, entails the dangers of explosion. In this article, all the quality tests performed on the raw materials and the metal pipe production process are mentioned, and the result of their optimization in terms of sampling, prototyping, and acceptance criteria in the quality control plan is given. In addition to destructive tests, three important non-destructive methods including industrial radiography, ultrasonic test, and eddy current test have been specially investigated. The statistical results of detectable defects for three specific sizes of pipes including 4, 6, and 8 inches have been collected. The final result of this essay is the optimization of high-frequency electric resistance welding pipe production.

Unveiling the influence of open metal sites in quasi ZIF-67 for eco-friendly catalysis of solvent-free aldehyde cyanosilylation

Quasi metal–organic frameworks (Q-MOFs) containing a high density of open metal centers are considered as an effective method of expanding the effectiveness of defective MOF-based catalysts. To achieve this, quasi ZIF-67 (Q-ZIF-67), having large scale structural defects in the framework, is produced through partial deligandation of ZIF-67 under controlled thermal treatment at 310 °C in air. This generates many unsaturated cobalt centers as Lewis acid sites, and results in the coexistence of micro and meso-pores within the Q-ZIF-67 network. Subsequently Q-ZIF-67 was employed in the catalytic cyanosilylation of benzaldehyde with trimethylsilyl cyanide, resulting in the corresponding cyanohydrin within 30 min under solvent free-conditions in air at 40 °C and room temperature with TOF values of 1.62, 1.53 min−1, respectively. The related cyanohydrin product was identified via 1H NMR. Importantly, Q-ZIF-67 displayed a highly efficient heterogeneous Lewis acid catalyst for the cyanosilylation of benzaldehyde compared to the pristine ZIF-67 and related cobalt oxide. Furthermore, investigating the impact of the electron-donating and electron-withdrawing para-substitutions on benzaldehyde revealed that electron-withdrawing groups are suitable for nucleophilic reactions. It was also observed that there was no significant decrease in catalytic activity after five catalytic runs. Thus, the Q-ZIF-67 has considerable potential as environmentally friendly catalyst for wide range of practical application in aldehyde cyanosilylation reactions.

Cashew phenol modified lignosulfonate strategy for the preparation of high-performance dye dispersants.

Lignin-based dye dispersants (LDD), as one of the most common lignin resource end-application product, is difficult to meet the rapidly developing needs of modern fiber dyeing due to their inherent structural defects. The efficient upgrading and modification of LDD is of great significance to the value-added application of lignin resources and the expansion of LDD sinking market. In this study, using industrial kraft lignin as raw material, cashew phenol was introduced into lignosulfonate in the form of CC bonds by ingenious utilizing the structural characteristics of lignin disordered condensation. Aromatic ring in cashew phenol could provide sufficient sulfonic acid group grafting sites, while C15 fatty chain could enhance steric hindrance effect. In the dispersibility test, the dispersing power showed 99.09 %, and the low/high temperature dispersion (LTD/HTD) were 5 s/4 and 6 s/4, respectively, higher than the dispersibility level of LDD in the market, has great commercial value and industrial potential. Combined with FTIR, 1H NMR, GPC and ICP, the structural properties of lignin were analyzed in detail, and the degree of sulfonation-condensation was balanced-optimized. The CC bond condensation process between cashew phenol and lignin was revealed, and the mechanism of action on dye particles was elucidated.

Effects of structural defects on dielectric properties of Nb-doped SrTiO3-based ceramics

In this study, the Nb-doped SrTiO3 (SNT) ceramics were prepared using the traditional solid-state reaction method. It was observed that the room temperature permittivity exhibited a significant increase from 102 to 104 as the partial pressure of oxygen in the sintering atmosphere gradually decreased. To elucidate the mechanism driving these observed changes in permittivity, the microstructure and dielectric properties of SNT ceramics were investigated. The results indicated that the presence of Ti3+/Ti4+ polar structure and the defect dipole [Ti4+∙e−Vo∙∙−Ti4+∙e] resulted in the increase of permittivity, but only [Ti4+∙e−Vo∙∙−Ti4+∙e] can reduced dielectric loss. The formation and concentration of these defects would be influenced by the oxygen partial pressure in the sintering atmosphere, consequently influencing the alteration in the permittivity.

Sb-anchoring single-crystal engineering enables ultra-high-Ni layered oxides with high-voltage tolerance and long-cycle stability

Ni-rich layered oxides are promising cathodes for Li-ion batteries, but the inherent structural defects result in severe surface/bulk degradation during long cycling, especially at high cutoff voltage. Herein we propose a Sb-anchoring single-crystalline engineering to enhance the microstructural and electrochemical stability of ultra-high-Ni layered oxides, where the surface-enriched Sb doping inhibits Li-Ni mixing, suppressing the undesired layered to mixed/rock-salt phase transformation; the bulk-doped Sb rivets into Ni sites, reinforcing the bulk phase stability; the single-crystal endows enhanced crack resistance and reduced surface area, preventing surface parasitic reactions and the subsequent proliferation of cathode electrolyte interfaces. In-situ XRD reveals an essential correlation between cycle stability and phase reversibility, whereas Sb doping into both surface and bulk structures showcases a continuous anchoring effect, largely enhancing the phase transformation reversibility. DFT calculations prove a high oxidation tolerance, as Ni2+ diffusion barrier is higher than the pure cathode. A representative Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2 cathode exhibits a high-voltage up to 4.6V, and a Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2//graphite full-cell demonstrates an ultra-high capacity retention of 93.4% after 1000 cycles at 1C in 3.0−4.2V. This simple and efficient cathode engineering will promote the promising application of Ni-rich layered oxides in high-energy Li-ion batteries.

Accumulation of oxygen interstitial-vacancy pairs under irradiation of corundum single crystals with energetic xenon ions

Single crystals of α-Al2O3 with broad sides oriented perpendicular to the c crystal axis have been irradiated by 231-MeV xenon ions with fluence varying from 5×1011 to 1014 ions/cm2. The spectra of radiation-induced optical absorption (absorption of a pristine crystal is subtracted) have been decomposed into Gaussians serving as a measure of oxygen-related Frenkel defects (vacancy-interstitial pairs). The concentration of all structural defects considered – vacancy-type F and F+ centers as well as oxygen interstitials – continuously increases with ion fluence. Therefore, radiation-induced origin of elementary absorption bands at 5.6 and 6.6 eV tentatively ascribed earlier to charged and neutral oxygen interstitials has been proved for the first time. The concentrations of charged interstitials (in the form of superoxide ions) have been directly determined by the EPR method. The evolution of cathodoluminescence bands typical of self-trapped excitons (VUV band at 7.6 eV) and F-type defects (bands peaked around 3.0 and 3.8 eV) with the rise of Xe-ion-irradiation fluence has been measured and analyzed.

Molecular diagnoses and candidate gene identification in the congenital heart disease cohorts of the 100,000 genomes project.

Congenital heart disease (CHD) describes a structural cardiac defect present from birth. A cohort of participants recruited to the 100,000 Genomes Project (100 kGP) with syndromic CHD (286 probands) and familial CHD (262 probands) were identified. "Tiering" following genome sequencing data analysis prioritised variants in gene panels linked to participant phenotype. To improve diagnostic rates in the CHD cohorts, we implemented an agnostic de novo Gene Discovery Pipeline (GDP). We assessed de novo variants (DNV) for unsolved CHD participants following filtering to select variants of interest in OMIM-morbid genes, as well as novel candidate genes. The 100kGP CHD cohorts had low rates of pathogenic diagnoses reported (combined CHD "solved" 5.11% (n = 28/548)). Our GDP provided diagnostic uplift of nearly one third (1.28% uplift; 5.11% vs. 6.39%), with a new or potential diagnosis for 9 additional participants with CHD. When a filtered DNV occurred within a non-morbid gene, our GDP prioritised biologically-plausible candidate CHD genes (n = 79). Candidate variants occurred in both genes linked to cardiac development (e.g. AKAP13 and BCAR1) and those currently without a known role (e.g. TFAP2C and SETDB1). Sanger sequencing of a cohort of patients with CHD did not identify a second de novo variant in the candidate dataset. However, literature review identified rare variants in HMCN1, previously reported as causative for pulmonary atresia, confirming the approach utility. As well as diagnostic uplift for unsolved participants of the 100 kGP, our GDP created a dataset of candidate CHD genes, which forms an important resource for further evaluation.

Adsorption‐photocatalysis for methylene blue dye removal by novel Fe‐MOFs through defect engineering

AbstractIn recent years, metal–organic frameworks (MOFs) have attracted much attention in environmental pollution control. However, most MOFs still have problems such as low utilization of visible light and easy recombination of photogenerated electrons and holes. In this study, novel defective Fe‐MOFs with appropriate structural defects were prepared by solvothermal method and used to remove methylene blue (MB) in aqueous phase through adsorption and photocatalysis. Defective Fe‐MOFs have Fe content as high as 10.31% with specific surface area of 40.95 m2/g, which is beneficial for both dye adsorption and photocatalytic process. Defective Fe‐MOFs have spindle‐like structures with sizes ranging from 40 nm to 100 nm and an average size of 69.1 nm, as well as some irregularly shaped nanoparticles. Irregular stacking of these two kinds of structure makes Fe‐MOFs appropriate structural defects, large specific surface area, and mesoporous structure. Kinetics and isotherms of dye adsorption process are consistent with pseudo‐first‐order kinetic model and Freundlich isotherm model, respectively. Defective Fe‐MOFs can absorb MB dye rapidly, reaching adsorption equilibrium within 60 min. Dye adsorption process is endothermic, spontaneous, and entropy‐increasing process. After 180 min visible light illumination, dye photocatalytic efficiency of the defective Fe‐MOFs reaches 97.56% in the condition of MB concentration as high as 30 mg/L. Consequently, defective Fe‐MOFs with appropriate structural defects, porous structure, high Fe‐O content, and strong electron‐donating amino groups have huge potential applications in removing organic dyes from the aqueous solution by a green and environmentally friendly way due to their high dye adsorption and dye photocatalytic activity.

Direct Regeneration of Industrial LiFePO4 Black Mass Through A Glycerol‐Enabled Granule Reconstruction Strategy

AbstractWith the increasing sales of electric vehicles, lots of spent lithium‐ion batteries (LIBs) assembled with LiFePO4 (LFP) cathodes will retire in the next few years, posing a significant challenge for their effective and environmentally‐friendly recycling. The main reason why spent LFP cathodes fail to re‐utilize lies in the lattice defects caused by lithium loss and structural defects resulting from stress accumulation. In this work, we propose an in situ granule reconstruction strategy to directly regenerate spent LFP black mass (S−BM) using glycerol in industry settings. The hydroxyl groups abundant in glycerol serves as electron donor that help reduce Fe (III) and repair Fe−Li antisite defects (FeLi). Additionally, the chelating properties of glycerol intervene with structurally disintegrated particles, inhibiting Oswald ripening effect and promoting bonding of grain boundaries to generate lamellar microcrystals with homogeneous grain size, recover their morphology and crystal structure after a facile annealing procedure. Furthermore, the regenerated LFP restores Fe−O bonds which further inhibits structural distortion and improve Li+ migration kinetics. As a result, the regenerated industrial LFP black mass (R−BM) exhibits superior lithium storage performance with a discharge capacity of 123.2 mA h g−1 after 500 cycles at 5.0 C (a capacity retention rate of 93.1 %).

Transfer Reconstruction from High-Frequency to Low-Frequency Bridge Responses Under Vehicular Loading with a ResNet

The reconstruction of bridge responses has been a significant area of focus within the field of structural health monitoring. This process entails the cross-reconstruction of responses from various cross-sections to identify any anomalies at specific locations, which may indicate the presence of structural defects. Traditional research has concentrated on simulating the relationships between different cross-sections for both high- and low-frequency components in isolation. However, this study introduces an innovative approach using a residual network (ResNet) to reconstruct high-frequency bridge responses under vehicular loading and demonstrates its applicability to low-frequency response reconstruction as well. The theoretical basis of this method is established through an analysis of the dynamics within a simplified vehicle-bridge-interaction (VBI) system. This analysis reveals that the transfer matrices for both high- and low-frequency components remain consistent across various loading conditions. Then, a data interception technique is introduced to separate high-frequency, low-frequency, and temperature-related components based on their spectral characteristics. The ResNet modeled the inter-sectional relationships of the high-frequency components and was then used to reconstruct the low-frequency responses under vehicular loading. The methodology was validated using a series of finite element models, confirming the uniformity of the transfer matrix between high- and low-frequency vibration components of the bridge. Field testing was also conducted to evaluate the practical effectiveness of the method. The proposed transfer–reconstruction method is expected to significantly reduce training dataset requirements compared with existing methods, thereby enhancing the efficiency of structural health monitoring systems.

Visible-Light-Activated TiO2-Based Photocatalysts for the Inactivation of Pathogenic Bacteria

Pathogenic bacteria in the environment pose a significant threat to public health. Titanium dioxide (TiO2)-based photocatalysts have emerged as a promising solution due to their potent antimicrobial effects under visible light and their generally eco-friendly properties. This review focuses on the antibacterial properties of visible-light-activated, TiO2-based photocatalysts against pathogenic bacteria and explores the factors influencing their efficacy. Various TiO2 modification strategies are discussed, including doping with non-metals, creating structure defects, combining narrow-banded semiconductors, etc., to extend the light absorption spectrum from the UV to the visible light region. The factors affecting bacterial inactivation, and the underlying mechanisms are elucidated. Although certain modified TiO2 nanoparticles (NPs) show antibacterial activities in the dark, they exhibit much higher antibacterial efficacies under visible light, especially with higher light intensity. Doping TiO2 with elements such as N, S, Ce, Bi, etc., or introducing surface defects in TiO2 NPs without doping, can effectively inactivate various pathogenic bacteria, including multidrug-resistant bacteria, under visible light. These surface modifications are advantageous in their simplicity and cost-effectiveness in synthesis. Additionally, TiO2 can be coupled with narrow-banded semiconductors, resulting in narrower band gaps and enhanced photocatalytic efficiency and antibacterial activities under visible light. This information aids in understanding the current technologies for developing visible-light-driven, TiO2-based photocatalysts and their application in inactivating pathogenic bacteria in the environment.

Assessment of impaired reinforced concrete dapped‐end beams: An analytical approach

AbstractReinforced concrete dapped‐end beams (DEBs) represent a unique structural type with the presence of recessed ends. The beam configuration is ideal for structural connections. However, the recessed area is structurally a disturbed region, and is vulnerable to embedded reinforcement deterioration. This study explored the potential of strength assessment of impaired DEBs via an analytical approach. A kinematics based model (KBM) was opted, and it was subjected to significant modifications to account to suit with distinct structural defects that were common to DEBs. The extended model (EKBM) was validated using experimental results available for eight beams. Both the load and failure mode predictions from the EKBM were found to be more accurate than those from the KBM, where the EKBM prediction offset was within a fair range of −23% to 15%. Furthermore, a parametric analysis was carried out to investigate the sensitivity of shear reinforcement deficiency and of reinforcement corrosion in the joint region on the beam load capacity. It revealed that the first two shear links were the most critical links. The load reduction was linearly proportional to the area reduction of reinforcement due to corrosion, however, the trend deviated from that at some combined deficiencies. The corroded reinforcement length was rather insensitive to the resulting beam strength.

Iodine Deficiency Exacerbates Thyroidal and Neurological Effects of Developmental Perchlorate Exposure in the Neonatal and Adult Rat

Thyroid hormones (THs) require iodine for biosynthesis and play critical roles in brain development. Perchlorate is an environmental contaminant that reduces serum THs by blocking the uptake of iodine from the blood to the thyroid gland. Using a pregnant rodent model, we examined the impact of maternal exposure to perchlorate under conditions of dietary iodine deficiency (ID) on the brain and behavior of offspring. We observed modest reductions in thyroxine (T4) in the serum of dams and no effect on T4 in pup serum in response to maternal exposure to 300 ppm of perchlorate in the drinking water. Likewise, serum T4 was reduced in ID dams, but, as with perchlorate, no effects were evident in the pup. However, when ID was coupled with perchlorate, reductions in pup serum THs and transcriptional alterations in the thyroid gland and pup brain were detected. These observations were accompanied by reductions in the number of cortical inhibitory interneurons containing the calcium-binding protein parvalbumin (Pvalb). Alterations in Pvalb expression in the neonatal brain were associated with deficits in the prepulse inhibition of acoustic startle in adult male offspring and enhanced fear conditioning in females. These findings support and extend structural defects in the brain previously reported in this model. Further, they underscore the critical need to consider additional non-chemical stressors in the determination of hazards and risks posed by environmental contaminants that affect the thyroid system.

Association of smoking with knee osteoarthritis structural defects and symptoms: an individual participant data meta-analysis

Prior meta-analyses have suggested a protective link between smoking and knee osteoarthritis (KOA), but they relied on aggregate data, potentially obscuring the true relationship. To address this limitation, we conducted an Individual Participant Data (IPD) meta-analysis using data from three large cohorts: the Osteoarthritis Initiative (OAI), the Multicenter Osteoarthritis Study (MOST), and the Cohort Hip and Cohort Knee (CHECK) study. Participants from 16 centers in the USA and Netherlands were categorized as current, former, or never smokers. We assessed six outcomes, three related to structural changes over 4–5 years of follow-up, and three related to changes in KOA symptoms over 2–2.5 years, 5 years, and 7–8 years of follow-up. First, the incidence of radiographic KOA was evaluated in 10,072 knees, defined as having a Kellgren-Lawrence grade ≥ 2 (‘radiographic KOA’) at follow-up but not at baseline. Second, the progression of radiographic KOA was evaluated in 5274 knees, defined as an increase in Kellgren–Lawrence grade between baseline and follow-up in knees that had radiographic KOA at baseline. Third, the incidence of symptomatic KOA was evaluated in 12,910 knees, defined as having radiographic KOA in addition to symptoms at follow-up but not at baseline. Fourth, fifth, and sixth, we investigated changes between baseline and all follow-ups in scores for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscales of pain, disability, and stiffness (in 2640 knees). There were no differences between smoking groups in any of these six outcomes. Our study, leveraging data from three large cohorts and the advantages of IPD, finds no evidence that smoking offers any protection against KOA, refuting the notion that smoking may benefit joint health.

Visualizing the Submolecular Organization of αβ-Tubulin Subunits on the Microtubule Inner Surface Using Atomic Force Microscopy.

Microtubules (MTs) are dynamic cytoskeletal polymers essential for mediating fundamental cellular processes, including cell division, intracellular transport, and cell shape maintenance. Understanding the arrangement of tubulin heterodimers within MTs is key to their function. Using frequency modulation atomic force microscopy (FM-AFM) and simulations, we revealed the submolecular arrangement of α- and β-tubulin subunits on the inner MT surface. We observed an undulating molecular arrangement of protofilaments (PFs) with alternating height variations, attributed to different structural orientations and the confirmation of αβ-tubulin heterodimers in adjacent PFs, forming bimodal lateral contacts, as confirmed by AFM simulations. Structural defects resulting from missing tubulin units were directly identified. This detailed structural information provides critical insight into the MT functional properties. Our findings highlight the potential of FM-AFM in liquid as a powerful tool for elucidating the complex interactions among MTs, MT-associated proteins, and other molecules, which are essential for understanding MT dynamics in the cellular context.

Light‐Driven Dynamic Defect‐Passivation for Efficient Inorganic Perovskite Solar Cells

AbstractDue to its soft lattice characteristics, all‐inorganic cesium lead halide (CsPbI3‐xBrx) perovskite is vulnerable to external environmental stress such as moisture, polar solvent, illumination. resulting in structural defects (VI, Ii, etc.) and ion mobility. However, most of the prior arts focus on short‐term and static passivation, which has a negligible effect on defects formed during solar cell operation. Herein, a photoisomerizable molecule, 1,3,3‐trimethylindolino‐8′‐methoxybenzopyrylospiran (OMe‐SP), exhibiting light‐driven pre‐isomeric (SP) and post‐isomeric (PMC) configurations, is employed as an interfacial protective layer on top of CsPbI3‐xBrx. The present strategy not only effectively suppresses migration of halogen ions, but also enables sustainable passivation of defects, thereby significantly reducing interfacial charge recombination and retarding perovskite degradation. Consequently, the OMe‐SP‐modified perovskite solar cells (PSCs) exhibit superior stability, maintaining 91% of their initial efficiency after aging 1032 h under maximum power point (MPP) tracking and continuous one sun illumination. Meanwhile, the OMe‐SP‐modified cell also achieves an impressive power conversion efficiency of 22.20%, which stands as the highest among all‐inorganic perovskite solar cells. Overall, the implementation of this robust strategy provides sustainable defect passivation and continuous suppression of ion migration for achieving both high PCE and stable inorganic perovskite.

Cyclin‐dependent kinase 13 is indispensable for normal mouse heart development

AbstractCongenital heart disease (CHD) has an incidence of approximately 1%. Over the last decade, sequencing studies including large cohorts of individuals with CHD have begun to unravel the genetic mechanisms underpinning CHD. This includes the identification of variants in cyclin‐dependent kinase 13 (CDK13), in individuals with syndromic CHD. CDK13 encodes a serine/threonine protein kinase. The cyclin partner of CDK13 is cyclin K; this complex is thought to be important in transcription and RNA processing. Pathogenic variants in CDK13 cause CDK13‐related disorder in humans, characterised by intellectual disability and developmental delay, recognisable facial features, feeding difficulties and structural brain defects, with 35% of individuals having CHD. To obtain a greater understanding for the role that this essential protein kinase plays in embryonic heart development, we have analysed a presumed loss of function Cdk13 transgenic mouse model (Cdk13tm1b). The homozygous mutants were embryonically lethal in most cases by E15.5. X‐gal staining showed Cdk13 expression localised to developing facial regions, heart and surrounding areas at E10.5, whereas at E12.5, it was more widely present. In the E15.5 heart, staining was seen throughout. RT‐qPCR showed significant reduction in Cdk13 transcript expression in homozygous compared with WT and heterozygous hearts at E10.5 and E12.5. Detailed morphological 3D analysis of embryonic and postnatal hearts was performed using high‐resolution episcopic microscopy, which affords a more detailed analysis of structures such as cardiac valve leaflets and endocardial cushions, compared with more traditional histological techniques. We show that both the homozygous and heterozygous Cdk13tm1b mutants exhibit a range of CHD, including ventricular septal defects, bicuspid aortic valve, double outlet right ventricle and atrioventricular septal defects. 100% (n = 4) of homozygous hearts displayed CHD. Differential expression was seen in Cdk13tm1b homozygous mutants for two genes known to be necessary for normal heart development. The types of defects, and the presence of CHD in heterozygous mice (17.02%, n = 8/47), are consistent with the CDK13‐related disorder phenotype in humans. This study provides important insights into the effects of reduced function of CDK13 in the mouse heart and contributes to our understanding of the mechanism behind this disorder as a cause of CHD.

Single‐Mode Lasing by Selective Mode Structure Breaking

AbstractSingle‐mode lasers are highly desirable for applications in optical communication, quantum information, and photonic computing, but their realization is challenging due to the competition of multiple closely spaced resonant modes in microcavities. This paper proposes a novel approach, termed mode structure breaking, to achieve high‐performance single‐mode lasing in an individual laser cavity. By introducing selective spatial structure defects, the mode structure of competing modes can be broken, enabling single‐mode selection without huge losses. As proof of concept, femtosecond (fs)‐laser ablation is experimentally employed to introduce external angle defects on a microdisk cavity, effectively eliminating mismatched competing modes and thus achieving single‐mode lasing output. The lasing characteristics are further optimized by incorporating a punched hole to suppress remaining high‐order lasing modes. Notably, the fabricated perovskite laser sources, which are called mode‐structure‐breaking lasers, demonstrate excellent single‐mode lasing properties, including stability, an ultralow threshold (≈2.31 µJ cm−2), and a narrow linewidth (≈0.15 nm). Conclusively, this comprehensive study of manipulating lasing mode by breaking mode structure may provide a promising approach to realizing single‐mode lasing in a single structure, which is significant for producing on‐chip laser source arrays for use in photonic integrated circuits.