Additional Defects Research Articles

Insight into the synergistic effect of defect and strong interface coupling on ZnIn2S4/CoIn2S4 heterostructure for boosting photocatalytic H2 evolution

Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions. In this work, an atomic-shared heterointerface is constructed between the defect-rich ZnIn2S4 (HVs-ZIS) and CoIn2S4 (CIS) via a defect-guided heteroepitaxial growth strategy. The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS, enhancing the internal electric field (IEF) in the ZnIn2S4/CoIn2S4 (HVs-ZIS/CIS) heterostructure. The defect structure in HVs-ZIS induces an additional defect level, improving the separation efficiency of photocarriers. Moreover, promoted by the IEF and intimate heterointerface, photogenerated electrons trapped by the defect level can migrate to the valence band of CIS, contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS. Consequently, the HVs-ZIS/CIS heterostructure performs a boosted H2 evolution activity of 33.65 mmol g−1 h−1. This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts.

Effect of Sm doping on structure, dielectric properties and microwave absorption performance of SrMnO3

In this work, Sr1-xSmxMnO3(x = 0,0.5) powders were prepared by solid-state reaction method. The effects of Sm doping on structure, electromagnetic properties and microwave absorption performance of SrMnO3 were systematically investigated by experimental characterizations and first-principles calculations. It is found that the doping of Sm transforms the hexagonal structure P63/mmc of SrMnO3(SMO) into an orthorhombic phase Pnma of Sr0.5Sm0.5MnO3 (SSMO) at room temperature. Sm doping and the increase of Mn3+ content induce the lattice distortion, resulting in octahedral torsion and the Mn–O–Mn bond angle towards 180°. Furthermore, doping introduces additional oxygen vacancies and defects in SMO, significantly enhancing various polarizations within the system. As a result, there is a substantial improvement in the microwave absorption capability of the doped sample. Compared to undoped SMO, SSMO performs excellent microwave absorbing properties in the higher frequency band and the value of reflection loss has increased by 29.47 dB at the optimal matching thickness.

A collection of novel Lotus japonicus LORE1 mutants perturbed in the nodulation program induced by the Agrobacterium pusense strain IRBG74.

The Lotus japonicus population carrying new Lotus retrotransposon 1 (LORE1) insertions represents a valuable biological resource for genetic research. New insertions were generated by activation of the endogenous retroelement LORE1a in the germline of the G329-3 plant line and arranged in a 2-D system for reverse genetics. LORE1 mutants identified in this collection contributes substantially to characterize candidate genes involved in symbiotic association of L. japonicus with its cognate symbiont, the nitrogen-fixing bacteria Mesorhizobium loti that infects root nodules intracellularly. In this study we aimed to identify novel players in the poorly explored intercellular infection induced by Agrobacterium pusense IRBG74 sp. For this purpose, a forward screen of > 200,000 LORE1 seedlings, obtained from bulk propagation of G329-3 plants, inoculated with IRBG74 was performed. Plants with perturbed nodulation were scored and the offspring were further tested on plates to confirm the symbiotic phenotype. A total of 110 Lotus mutants with impaired nodulation after inoculation with IRBG74 were obtained. A comparative analysis of nodulation kinetics in a subset of 20 mutants showed that most of the lines were predominantly affected in nodulation by IRBG74. Interestingly, additional defects in the main root growth were observed in some mutant lines. Sequencing of LORE1 flanking regions in 47 mutants revealed that 92 Lotus genes were disrupted by novel LORE1 insertions in these lines. In the IM-S34 mutant, one of the insertions was located in the 5´UTR of the LotjaGi5g1v0179800 gene, which encodes the AUTOPHAGY9 protein. Additional mutant alleles, named atg9-2 and atg9-3, were obtained in the reverse genetic collection. Nodule formation was significantly reduced in these mutant alleles after M. loti and IRBG74 inoculation, confirming the effectiveness of the mutant screening. This study describes an effective forward genetic approach to obtain novel mutants in Lotus with a phenotype of interest and to identify the causative gene(s).

Effect of confined Mn oxides on regulating capability of activated coke for persulfate-based oxidation of a sweetener acesulfame

Mn oxides are confined within the porous structure of activated coke (ACO) via impregnation followed by calcination treatment. The Mn-ACO sample calcined at 600 °C (Mn-ACO600) demonstrated superior performance despite containing only a minute atomic ratio of 0.11 % Mn on its surface. This treatment led to a slight increase in the specific surface area and pore volume of ACO, with a significant enhancement in the proportion of micropores, rising from 54.2 % in ACO to 71.8 % in Mn-ACO600. Raman spectroscopy indicated additional defects in Mn-ACO, while XPS analysis confirmed the coexistence of Mn(II), Mn(III), and Mn(IV) oxides. Although ACO adsorption alone was ineffective in removing acesulfame (ACE), Mn-ACO600 achieved a removal rate of 19.0 %. The introduction of peroxydisulfate (PDS) further boosted the degradation of Mn-ACO600, with a Kapp value that was 2.28 times of that of the combined Mn-ACO600 adsorption and PDS oxidation process, indicating a remarkable synergistic effect. To optimize the experimental conditions, a response surface methodology design analysis was conducted, revealing that solution pH and the dosage of Mn-ACO600 were crucial factors. Furthermore, the study confirmed non-radical oxidizing species, such as 1O2 and h+, played a predominant role in the process, with relatively minor contributions from radical oxidizing species.

Performance of perovskite solar cells based on SnO<sub>2</sub>:DPEPO hybrid electron transport layer

The electron transport layer is an important functional layer of perovskite solar cells, and its surface and internal defects are critical parts of limiting the performance improvement of perovskite solar cells. The double electron transport layer (double ETL) strategy can effectively passivate inherent defects in the electron transport layer (such as SnO<sub>2</sub>) and improve electron extraction and transport between the functional layers, providing an effective way for developing efficient and stable PSCs. However, due to the existence of independent interfaces in the dual ETL, the cell mismatch in different ETL materials also leads to additional carrier defects, hindering the continuous advancement of the dual ETL strategy. This work proposes a strategy for introducing di[2-((oxo)diphenylphosphino)phenyl]ether (DPEPO) into SnO<sub>2</sub> ETL to design a hybrid electron transport layer strategy. Using the hole-blocking effect of DPEPO, which has a higher HOMO energy level and good ability to transfer electrons, the intrinsic defects in SnO<sub>2</sub> are successfully passivated, while significantly improving the crystalline quality of the SnO<sub>2</sub> film surface. So, avoiding the direct contact between the perovskite photoactive layer and the conductive substrate can effectively improve the extraction and transport of electrons. Due to the preparation of high-quality electron transport layer, the crystallization regulation of perovskite thin film is further achieved, thereby improving the performance of perovskite solar cells. Finally, 21.53% of the power conversion rate is obtained, the open-circuit voltage (<i>V</i><sub>OC</sub>) reaches 1.220 V, the short-circuit current (<i>J</i><sub>SC</sub>) is 23.19 mA/cm<sup>2</sup>, and the fill factor (FF) is 76.11%. This efficiency is 1.39% higher than that of the control one. It is shown that the hybrid electron transport layer strategy can not only optimize the carrier transport dynamics efficiently and reduce the device performance affected by the defects in the functional layer significantly, but also regulate the perovskite crystallization, which has the prospect for preparing high-performance solar cells.

Enhancing hydrogen evolution reaction activity through defects and strain engineering in monolayer MoS2.

Molybdenum disulfide (MoS2) has recently emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER). However, the poor in-plane electrical conductivity and inert basal plane activity pose major challenges in realizing its practical application. Herein, we demonstrate a new approach to induce biaxial strain into CVD-grown MoS2 monolayers by draping it over an array of patterned gold nanopillar arrays (AuNAs) as an efficient strategy to enhance its HER activity. We vary the magnitude of applied strain by changing the inter-pillar spacing, and its effect on the HER activity is investigated. To capitalize on the synergistic effect of improved ΔG H via strain engineering and leverage basal plane activation by introduction of sulphur vacancies, we further exposed the strained MoS2 monolayers to oxygen plasma treatment to create S-vacancies. The strained MoS2 on AuNAs with optimal inter-pillar spacing is exposed to oxygen plasma treatment for different durations, and we study its electrocatalytic activity towards the HER using on-chip microcell devices. The strained and vacancy-rich monolayer MoS2 draped on AuNAs with a 0.5 μm inter-pillar spacing and exposed to plasma for 50 s (S0.5μmV50-MoS2) is shown to exhibit remarkable improvement in HER activity, with an overpotential of 53 mV in 0.5 M H2SO4. Thus, the synergistic creation of additional vacancy defects, along with strain-induced active sites, results in enhancement in HER performance of CVD-grown monolayer MoS2. The present study provides a highly promising route for engineering 2D electrocatalysts towards efficient hydrogen evolution.

Clinical Presentation and Therapy of Truncus Arteriosus.

Truncus arteriosus (TA, also known as common arterial trunk) consists of only one great artery ("the truncus") with a semilunar valve (truncus valve) arising from the heart and an additional ventricular septal defect and (Fig. 50.1). This great artery is positioned above the ventricular septal defect and gives rise to the coronary arteries, the pulmonary arteries, and the aortic arch. Historically, TA has been classified by Collet and Edwards in three types, where in type I there was a common pulmonary artery truncus, in type II the left and right PA arise separately but close to each other, in type III both PA arise independently; in addition, there was a type IV that was later characterized as pulmonary atresia with VSD and major aortopulmonary collateral arteries arising from the descending aorta.

Notice of Violation of IEEE Publication Principles: Design of Cost Efficient Modular Digital QCA Circuits using Optimized XOR Gate

Notice of Violation of IEEE Publication Principles “Design of Cost Efficient Modular Digital QCA Circuits using Optimized XOR Gate” by Suhaib Ahmed and Syed Farah Naz in IEEE Transactions on Circuits and Systems II: Express Briefs After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE’s Publication Principles. This paper contains significant portions of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission. “Design and Analysis of a Novel Low-Power Exclusive-OR Gate Based on Quantum-Dot Cellular Automata” By Haotian Chen, Hongjun Lv, Zhang Zhang, Xin Cheng and Guangjun Xie in Journal of Circuits, Systems, and Computers, Vol. 28, No. 8, 2017 The advantages such as high operating frequency (in the range of few THz), low power dissipation, small size and high density in the nano regime has led to the application of Quantum dot Cellular Automata (QCA) in designing various digital circuits. In this brief, an ultra-efficient two input XOR gate design in QCA is proposed. It is a single layer design consisting of only 9 cells with no crossover and operating on cell to cell interaction. The functionality of the proposed gate has been verified at both physical and simulation level. In addition to this, fault tolerance to single cell missing defect, single cell addition defect and single cell displacement defect of the proposed XOR gate has also been presented. Based on the performance evaluation, it is seen that the proposed XOR gate has least cell count, least area and least latency which in turn leads to least circuit cost. Also, the proposed design dissipates least energy. The applicability of proposed XOR gate has also been investigated by designing various cost efficient digital circuits such as full adder, parity checker, etc.

Band Engineering Through Pb-Doping of Nanocrystal Building Blocks to Enhance Thermoelectric Performance in Cu3SbSe4.

Developing cost-effective and high-performance thermoelectric (TE) materials to assemble efficient TE devices presents a multitude of challenges and opportunities. Cu3SbSe4 is a promising p-type TE material based on relatively earth abundant elements. However, the challenge lies in its poor electrical conductivity. Herein, an efficient and scalable solution-based approach is developed to synthesize high-quality Cu3SbSe4 nanocrystals doped with Pb at the Sb site. After ligand displacement and annealing treatments, the dried powders are consolidated into dense pellets, and their TE properties are investigated. Pb doping effectively increases the charge carrier concentration, resulting in a significant increase in electrical conductivity, while the Seebeck coefficients remain consistently high. The calculated band structure shows that Pb doping induces band convergence, thereby increasing the effective mass. Furthermore, the large ionic radius of Pb2+ results in the generation of additional point and plane defects and interphases, dramatically enhancing phonon scattering, which significantly decreases the lattice thermal conductivity at high temperatures. Overall, a maximum figure of merit (zTmax) ≈ 0.85 at 653 K is obtained in Cu3Sb0.97Pb0.03Se4. This represents a 1.6-fold increase compared to the undoped sample and exceeds most doped Cu3SbSe4-based materials produced by solid-state, demonstrating advantages of versatility and cost-effectiveness using a solution-based technology.

The Effect of Point Defects on Young’s Modulus of the Off-Stoichiometric Al3X (X = Li, Sc, and Zr) Phases: A First-Principles Study

L12-Al3X (X = Li, Sc, and Zr) precipitates are the main strengthened phases of high-strength aluminum alloys and are critical for aerospace structural materials. Point defects and substitutional ternary elements change the mechanical properties of Al3X. In this paper, the effect of point defects, including vacancy, antisite, and substitutional element addition defects on the elastic modulus of the off-stoichiometric Al3X (X = Li, Sc, and Zr) phase were investigated by using first-principle calculations. The formation enthalpies of the defective Al3X alloy and isolated point defects in Al3X were calculated, and the results showed that the defects have an effect on the structure and elasticity of the off-stoichiometric Al3X phases. The lattice distortion, elastic constants, and elastic moduli were further investigated. It was found that the point defects increased the Young’s modulus for Al3Zr, and the doping of Er improved the Young’s modulus for off-stoichiometric Al3Li and Al3Sc. Adjusting the position of vacancies can improve the elastic modulus. In addition, the doping of substitutional elements (especially Sc, Ti, Zr, Hf, Ta, Mn, Ir, and Cf) can greatly increase the Young’s modulus of off-stoichiometric Al3Li.

Doping induced mixed polytypic interfaces of MoS2 for superior electrocatalytic hydrogen evolution

Metallic 1Tphase of MoS2 is desirable for accelerating electrochemical hydrogen generation from water due to its excellent electrical conductivity. However, it is challenging to synthesize stable 1T-MoS2 on a large scale using conventional chemical or physical routes. Here in, we report highly durable Mn-doping assisted in-plane 1T/2H mixed phases of MoS2 synthesized by a simple one-step hydrothermal method. The Mn-doping not only results in a favourable electronic modification in the host lattice but also in a structural evolution from 2H (trigonal prismatic) to 1T (octahedral) phase through sulfur-plane gliding with additional defects. The 1T/2H interfaces exhibit more active sites for hydrogen evolution reaction (HER) than its bulk 2H-counterpart. The developed electrode shows relatively low overpotential of 95 mV at a current density of 10 mA/cm2 and a low Tafel slope of 72 mV/dec in 0.5 M H2SO4. In addition, Density Functional Theory based calculations also support that Mn-doping in pristine 2H-MoS2 encourages a structural phase separation. Locally hybridized d-orbitals of Mn induce the formation of 2H/1T interfaces. It results in the delocalization of electrons, and thus facilitates the hydrogen adsorption and desorption process, better than the 2H phase.

Additive-free electroless deposition on graphene/copper foil: Photo-induced and defect-assisted approach for environmentally friendly plating

The environmental toxicity of chemicals used in electroless plating process is often overlooked. In fact, the wastewater from the electroless plating process contains metal complexes, reducing agents and stabilizers that can create hazard to our environment. To address this concern, an additive-free electroless deposition process on graphene/Cu foil is proposed. The defect structure of graphene plays a pivotal role by acting as a reservoir for concentrating photoelectrons generated from ultra-thin cuprous oxide (Cu2O) located at the interface of graphene and Cu foil upon exposure to light irradiation. In the Cu ion solution, Cu ions were anchored on the defect sites and formed a Cu-C4 structure with graphene. The Cu-C4 sites accumulate abundant photoelectrons and trigger the reduction of Cu ions to form island-like growth of Cu, which immediately was oxidized to Cu2O, leaving only a small portion of metallic Cu. Concurrently, the presence of Cu ions induces the generation of additional defect sites on graphene, providing further growth sites for Cu deposition. This process continues until the entire graphene surface is covered by the deposited Cu2O. Ultimately, the deposition of metallic oxides with lower redox potential can be achieved. The proposed deposition mechanism assisted by irradiation of photocatalyst and defect structure of graphene material provides a truly environmentally friendly electroless plating process. By eliminating the need for additives and significantly reducing the environmental hazards associated with electroless plating, this method holds great promise for sustainable materials manufacturing.

Engineering Mn–O strength in manganese oxide catalyst to enhance propane catalytic oxidation

Developing highly active and thermally stable transition-metal-oxide catalysts for light alkane catalytic oxidation is of great importance but very challenging. In the work, the catalytic performance for propane deep oxidation was significantly enhanced on the Mn1NixOy solid solution catalyst by weakening the Mn–O bond strength of manganese oxide. The characterization results combined with DFT calculations demonstrated that the introduction of Ni could create additional defect sites, resulting in a significant improvement of the adsorption and the activation of both propane and oxygen molecules. The optimal Mn1Ni0.15Oy catalyst exhibits abundant oxygen vacancies with low MnO bond strength, high redox ability and oxygen mobility, which account for its superior activity. Specifically, the specific reaction rate on Mn1Ni0.15Oy is three times higher than that on pure Mn2O3. Moreover, a Mn1Ni0.15Oy/cordierite monolithic catalyst was made by wash-coating method, and exhibited remarkable catalytic performance and stability on catalytic oxidation of propane during the 45 days (1080 h) on stream, even after tens of high temperature thermal shocks (up to 650 ℃), which declared to be satisfied for practical industrial applications. This work will shed light on designing high-efficiency and long-life environmental catalyst for VOCs elimination.

Controlling of precursor micelle size by ternary co-spacer cations for efficient pure red quasi-2D PeLEDs with recommendation 2020 color coordinates

Quasi-two-dimensional (quasi-2D) perovskites have emerged as one of the most promising luminescent materials owing to their outstanding optoelectronic properties and facile solution processability. However, high-performance pure red quasi-2D perovskite light-emitting diodes (PeLEDs) still remain a great challenge due to wide phase distribution and inefficient quantum well energy transfer. Here, we develop a ternary co-spacer cations system to vary the micelle size of the precursor solution and to modulate the phase distribution in film using phenylbutyl-ammonium (PBA+) as the third spacer cation, which has stronger binding energy with lead-halide octahedron. By virtue of its additional defect passivation effect, the resulting device displays a champion maximum external quantum efficiency (EQE) of 15.7 % with an electroluminescent peak at 631 nm and Commission Internationale de l’Éclairage (CIE) coordinates of (0.709, 0.290) as well as excellent spectral stability. This work provides useful guidance for perovskite phase modulation and the development of highly efficient pure-red PeLEDs.

Abstract B055: Characterization of highly selective and CNS-penetrant PARP1 inhibitors

Abstract First-generation PARP1/2 inhibitors are FDA-approved for cancers such as breast, ovarian prostate and pancreas and provide significant therapeutic benefit to patients whose tumors harbor BRCA1 or BRCA2 mutations or homologous recombination deficiency (HRD). However, their use is associated with hematological toxicities that narrow their therapeutic index and restrict their application, particularly in combination with standard-of-care chemotherapy. All four FDA-approved PARP1 inhibitors are largely non-selective for the closely related enzyme PARP2, inhibition of which has been shown to drive hematotoxicity. Hence, the development of second-generation molecules highly selective for PARP1 over PARP2 offers a significant opportunity to 1) dramatically enhance therapeutic index, 2) enable additional precision medicine/combination approaches with chemotherapy, radiotherapy, immunotherapy and targeted agents and 3) expand the addressable patient population to those whose tumors harbour additional DDR defects. Utilising X-ray crystallography and structure-based drug design, we describe the characterization of exquisitely selective PARP1 inhibitors. These molecules demonstrate high potency in multiple biochemical and cell-based assays, including viability and colony forming unit read-outs in BRCA-deficient cancer cells, whilst sparing HR-proficient cancer cell lines and primary cells. The molecules are potent PARP1-DNA trappers and exhibit high selectivity across the PARP family and wider secondary pharmacology targets. The molecules potentiate the activity of ATR inhibitors when tested in ATM-deficient cancer cell lines. This chemical series generally exhibits highly desirable physico-chemical and in vitro ADME properties, which translate to high oral bioavailability and low clearance in rodent PK studies. Exemplar molecules also demonstrate high rat CNS penetrance using in vivo microdialysis. Lead molecules yield deep and durable dose-dependent anti-tumor efficacy in a variety of BRCAm xenograft models with responses continuing after cessation of treatment. The compounds demonstrate strong PK/PD relationships which correlate with anti-tumor efficacy using inhibition of tumor PARylation as a PD read-out. Strikingly, the molecules demonstrate compelling anti-tumor efficacy in BRCA-deficient xenograft models that are known to be largely resistant to FDA-approved non-selective PARP1/2 inhibitors. Taken together, these data predict low once daily therapeutic oral dosing based on a highly favorable pre-clinical PK profile and potent in vivo efficacy, with the potential to demonstrate improved efficacy and tolerability compared to marketed PARP inhibitors. In summary, we describe the characterization of next generation potent and selective CNS-penetrant PARP1 inhibitors. These molecules have the potential for an improved safety profile and greater combination potential with standard-of-care and targeted anti-cancer therapies. Citation Format: Phillip M Cowley, Barry E McGuinness, Gillian M Campbell, Alan Wise. Characterization of highly selective and CNS-penetrant PARP1 inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B055.

Highly Reliable Van Der Waals Memory Boosted by a Single 2D Charge Trap Medium.

Charge trap materials that can store carriers efficiently and controllably are desired for memory applications. 2D materials are promising for highly compacted and reliable memory mainly due to their ease of constructing atomically uniform interfaces, however, remain unexplored as being charge trap media. Here it is discovered that 2D semiconducting PbI2 is an excellent charge trap material for nonvolatile memory and artificial synapses. It is simple to construct PbI2 -based charge trap devices since no complicated synthesis or additional defect manufacturing are required. As a demonstration, MoS2 /PbI2 device exhibits a large memory window of 120V, fast write speed of 5 µs, high on-off ratio around 106 , multilevel memory of over 8 distinct states, high reliability with endurance up to 104 cycles and retention over 1.2 × 104 s. It is envisioned that PbI2 with ionic activity caused by the natively formed iodine vacancies is unique to combine with unlimited 2D materials for versatile van der Waals devices with high-integration and multifunctionality.

Evaluation of Couples at Risk for Hemoglobin Disorders in Italy: The Results of an 18-Month Retrospective Observational Single-Center Study

Background: Hemoglobinopathies are genetic disorders caused by mutations in the genes encoding globin chains. These conditions are the most common monogenic disorders worldwide, resulting in significant morbidity and mortality among those affected by the most severe forms. Antenatal evaluation for thalassemia and sickle cell disease (SCD) enables couples to know their reproductive risk, thus allowing an informed reproductive choice. However, in certain areas, couples do not often receive the appropriate counseling at the appropriate time. Aim: The aim of this study is to describe the characteristics of couples referred to our tertiary referral center in Milan, Italy, for evaluation of hemoglobinopathy risk and their management. Methods: in our Institution, a diagnostic-therapeutic pathway involving the Hemoglobinopathies unit, the Medical Genetic unit, and the central laboratory has been implemented. Subjects referred to the Institution, and their partner, underwent the following laboratory tests: complete blood count, hemolysis and iron parameters, vitamin pattern, and hemoglobin (Hb) pattern by high-performance liquid chromatography (HPLC). The couples were then evaluated by a hemoglobinopathy expert, and those at risk for Hb disorders were offered a molecular analysis. Couples were then referred to the geneticist to receive the results of the molecular analysis, discuss the genetic risk for the fetus and, in case of high risk, discuss possible reproductive choices (i.e., prenatal diagnosis, pre-implantation diagnosis). We retrospectively collected and analyzed couples' data referred to our center from the 1 st of July 2021 to the 31 st of December 2022. Results: Three hundred and fifty-one couples were evaluated for hemoglobinopathies over 18 months. The median age was 34 years, with a tendency for younger age in female partners; 67% (234/351) of the women were already pregnant at the time of evaluation (median gestational age 18 weeks, range 7-37), while 33% (117/351) were referred for preconception counseling. Individuals from more than 48 different countries were screened, and the most represented countries of origin included: Italy (50%), Nigeria (6%), Bangladesh (4%), and Ivory Coast (4%), underpinning a vastly diverse genomic background. The referral was triggered by either evidence of microcytic anemia (58%) or HPLC anomalies (42%), including Hb variants, HbA2 anomalies, or elevated HbF in at least one partner. 55% of the referrals did not require additional testing. The remaining 45% (158/351) underwent advanced molecular tests to determine the nature of the Hb defect, guided by the results of the first-level panel. Among these, 33 couples (12% of the total) were found to be at risk for transmission of severe clinical forms of β-thalassemia, sickle cell anemia, or compound β-disorder heterozygosity (HbS/β-thal, HbC/HbS). One additional couple (0.4%) was at risk for HbH disease. In addition, 4 couples (1.5%) were found to be at risk for thalassemia intermedia combining a β-thalassemia mutation and α-gene triplication. Of the above, all 34 couples underwent invasive fetal evaluation: 24 women underwent chorionic villous sampling, while 10 received amniocentesis. A diagnosis of thalassemia in the fetus was reported in 6/34 (18%) cases and 3 (9%) of SCD. Interestingly, during the 18 months of observation, among the evaluated adult subjects, we found 4 cases of non-transfusion dependent thalassemia (NTDT) and 1 of HbS/β-thal in otherwise healthy subjects. All 4 cases of NTDT resulted from α-gene triplication paired with a β-thalassemia heterozygous defect. Furthermore, α triplication was found alone in 4 subjects without additional Hb gene defects. Overall, α triplication was detected in 9 out of 154 (5.8%) individuals who underwent HBA gene analysis. Conclusion: The median gestational age at presentation was high, leading to a limited time for couples to receive the appropriate counseling to make an informed reproductive choice. Increasing awareness across all involved specialists remains the mainstay for an effective prevention program to promptly identify at-risk couples and offer counseling at the right time. In addition, the relatively high incidence of α triplication in our population of asymptomatic and hematologically normal subjects and the new diagnosis of 4 NTDT warrants further studies to confirm the prevalence of α triplication in the general population.

Colloidal synthesis and optical properties of Cs2ZnBr4 and Cs3ZnBr5 nanocrystals

A framework to understand the effects of an oxide-ligand environment on the photoluminescence (PL) of rare-earth-element-doped oxynitride compounds is well established, whereas the effects of halide coordination on crystal field splitting and the associated PL emission are rarely studied. In this paper, we report a synthetic route to alkali metal halide NCs of Cs2ZnBr4 and Cs3ZnBr5 with a broad blue PL emission and large Stokes shift. In particular, the zero-dimensional Cs3ZnBr5 phase, in which the isolated [ZnBr]42− units were completely separated by surrounding Cs+ cations, exhibited a strong blue PL emission at 437 nm with a PL quantum yield of 8.92 %. The formation of additional trap states or defects in the Cs3ZnBr5 crystalline lattice can be associated with a relatively considerable bands at 345 and 400 nm of the optical band edge, resulting in singlet-to-singlet transition of localized excitons with a short lifetime of 3.74 ns. Therefore, herein we demonstrate that tunable alkali metal halide NCs have considerable potential for optoelectronic applications.

Petaloid N-doped reduced graphene oxide supported zero-valent iron as catalyst activated peroxydisulfate for effective oxidation of β-hexachlorocyclohexane

Developing an efficient heteroatom-doped Fe-carbon catalyst is of great significance for the remediation of contaminated water and soil. In this study, a three-dimensional petaloid N-doped reduced graphene oxide (N-rGO)-supported nanoscale zero-valent iron (nZVI) composite (nZVI@N-rGO) was successfully prepared and applied to activate peroxydisulfate (PDS) to remove typical organochlorine pesticides (OCPs) from contaminated water and soil. The results indicated that N doping not only restructured the surface morphology of rGO and generated a petaloid nanosheet structure but also introduced additional defect sites for the loading of nZVI. nZVI@N-rGO effectively activated PDS to degrade β-hexachlorocyclohexane (β-HCH) in aqueous solution and contaminated soil. Characterization of the reaction process revealed that SO4∙-, •OH, 1O2 and O2∙- were the reactive species involved in β-HCH degradation and that the abundant N-doped sites and high conductivity of nZVI@N-rGO promoted the generation of reactive species and mediated direct electron transfer. Furthermore, the petaloid structure of N-rGO allowed for greater contact of PDS and β-HCH with nZVI, which improved the mass transfer of reactants. nZVI@N-rGO has good adaptability to different anions, humic acid concentrations and pH conditions in water. This work provides the necessary inspiration and guidance for the practical application of Fe-Carbon catalysts in the remediation of water and soil contaminated by OCPs.

Abstract 11801: Timing of Critical Congenital Heart Defect (CCHD) Detection at 7 U.S. Sites, the Birth Defects Study to Evaluate Pregnancy Exposures (BD-STEPS), 2014-2018

Background: CCHD detection prenatally or at birth hospitalization may reduce infant mortality and morbidity, yet little is known about prevalence and characteristics associated with timing of detection. Objective: To examine prevalence and characteristics associated with prenatal and late (>3 days after birth) detection of CCHD among infants in BD-STEPS, a multi-site population-based case-control study of risk factors for birth defects. Methods: Liveborn infants with non-syndromic CCHD without genetic causes born 2014-2018 with interviewed mothers were included. Timing of detection was based on date of earliest fetal or postnatal echocardiogram. Multivariable log-binomial models calculated adjusted prevalence ratios (aPR) for prenatal (vs postnatal) and late (vs not late) CCHD detection, by clinical and demographic characteristics. Log-linear models evaluated trends over time. Results: Among the 588/672 infants with CCHD and complete data, most infants’ mothers were Non-Hispanic White (53.4%), had some prenatal insurance (94.4%), and were multiparous (74.5%). Prenatal detection increased from 2014 to 2018 (24.7% to 40.1%) while late detection decreased (22.4% to 8.7%, Fig 1). Hypoplastic left heart syndrome had the highest prenatal detection (58.6%); late detection was highest for coarctation of the aorta (41.7%). Prenatal detection was more likely in infants of mothers 30-34 vs. 25-29 years at delivery (aPR=1.4, 95% confidence interval 1.0-1.9), and with additional non-cardiac defects (1.2, 1.1-1.4), and less likely among infants of mothers with <11 years of education vs. > bachelor’s degree (0.6, 0.3-1.0). Late detection was more likely among infants of mothers without prenatal insurance (1.8, 1.1-3.1), and less likely among those with non-cardiac defects (0.4, 0.2-0.8). Conclusion: From 2014 to 2018, prenatal detection increased and late detection decreased. Yet, disparities in detection by maternal insurance and education were observed.