Complete Cleavage Research Articles

A Biodegradable, Stretchable, Healable, and Self-Powered Optoelectronic Synapse Based on Ionic Gelatins for Neuromorphic Vision System.

Optoelectronic synapses have gained increasing attentions as a fundamental building block in the development of neuromorphic visual systems. However, it remains a challenge to integrate multiple functions into a single optoelectronic synapse that can be widely applied in wearable artificial intelligence and implantable neuromorphic vision systems. In this study, a stretchable optoelectronic synapse based on biodegradable ionic gelatin heterojunction is successfully developed. This device exhibits self-powered synaptic plasticity behavior with broad spectral response and excellent elastic properties, yet it degrades rapidly upon disposal. After complete cleavage, the device can be fully repaired within 1min, which is mainly attributed to the non-covalent interactions between different molecular chains. Moreover, the recovery and reprocessing of the ionic gelatins result in optoelectronic properties that are virtually indistinguishable from their original state, showcasing the resilience and durability of ionic gelatins. The combination of biodegradability, stretchability, self-healing, zero-power consumption, ease of large-scale preparation, and low cost makes the work a major step forward in the development of biodegradable and stretchable optoelectronic synapses.

Titin mechanical unloading disrupts sarcomere tensional homeostasis triggering fast, non-canonical myocardial fibrosis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): We acknowledge funding from Ministerio de Ciencia e Innovación (Madrid, Spain) through grant FJC2021 047055-I and European Research Council (ERC) through grant H2020-ERC-2020-COG (ProtMechanics-Live). Background/Introduction Stresses exerted during myocardial contraction and relaxation cycles are mainly braced by mechanical proteins located in the extracellular matrix (ECM) and cardiomyocytes (CMs). Titin (TTN) is a gigantic protein that scaffolds the sarcomere (i.e. the basic unit of contraction). Since most of the CM cytoskeleton is occupied by sarcomeres, titin is an essential structural hub for the maintenance of a homeostatic level of mechanical tension. Purpose It has been shown that mechanical disruption of the ECM affects the equilibrium forces between CMs and the ECM, leading to morphological changes in sarcomeres. However, potential alteration of tensional homeostasis resulting from defective mechanics of CM proteins remains unknown due to the lack of tools for in vivo studies. Therefore, the aim of this study is to explore the in vivo response of the myocardium to the abrupt cessation of the mechanical properties of titin. Methods For this purpose, we have experimentally challenged CMs to a tensional unloading by means of a titin cleavage model (TEVs-TTN) [1], both in vitro, using neonatal CM (NMCM), and in vivo. In this model, a cassette with a tobacco etch virus protease (TEVp) recognition sequence has been included in the I-band of titin. Transducing TEVp with adeno-associated virus (myoAAV), we were able to cleave titin in living CMs, ceasing only its mechanical properties. Samples were analyzed using an array of techniques such as histology, immunofluorescence and bulk and single-nucleus RNAseq. Results Our results show that while in NMCM we obtain a complete titin cleavage, in vivo we observe mosaic expression of TEVp and no more than 30% cleavage of the protein. In both cases, TEVp expression in TEVs-TTN does not affect cell viability. However, mild myocardial titin cleavage leads to a fibrotic response in less than six days, characterized by an increase in interstitial collagen and an expansion of cardiac fibroblasts population. Transcriptional and phospo-SMAD2/3 analysis results suggest that this fibrotic response occurs without activation of the canonical TGFβ pathway. Conclusion Taken together, our results suggest that the loss of titin mechanical-structural function in cardiomyocytes derived from the cleavage of a single peptide bond elicits a fast fibrotic compensatory response in the myocardium through intercellular communication with fibroblasts.

Copper‐Mediated Selective Multiple Inert Chemical Bonds Cleavage for Cyanation of Indoles via Tandem Carbon and Nitrogen Atom Transfer

Comprehensive SummaryThe activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom‐ and step‐economic synthesis. Undoubtedly, selectively activating and transforming multiple inert chemical bonds is an even more intriguing and demanding task in synthetic chemistry. However, due to its inherent complexity and extreme challenges, this endeavour is rarely accomplished. We report a copper‐mediated complete cleavage and selective transformation of multiple inert chemical bonds of three easily available feedstocks, i.e., a sp2C—H bond in indoles, three sp3C—H bonds and one C—N bond in a methyl carbon atom in TMEDA, and the C≡N triple bond in CH3CN. This reaction proceeds via tandem carbon and nitrogen atom transfer, and allows for the direct and efficient cyanation of indoles, presenting a simple and direct alternative for synthesizing 3‐cyanoindoles.

Enhanced catalytic hydrogenolysis of natural rubber to natural gas over Ru/ZrO2 via phase control strategy

The inert CC and C-C bonds is a major limitation for the degradation and utilization of rubber wastes, which has resulted in the increasingly serious environmental crisis. Here we developed an efficient strategy to catalyze complete cleavage of CC and C-C bonds in natural rubber by the enhanced reaction activity of Ru-based catalysts with the modulated ZrO2 crystal phases. And 95.0% of gas carbon yield with 98.6 mol% of CH4 and 1.4 mol% of C2-C4 hydrocarbons was achieved over Ru/m-ZrO2, which was more than 3 times higher than gas carbon yield over Ru/c-ZrO2 and Ru/t-ZrO2. The investigation on reaction pathway displayed that the primary hydrogenation of CC bonds with high bond energy would promote the transformation of natural rubber. The Ru0 species and spill-over hydrogen in Ru/m-ZrO2 catalyst acted in synergy for the catalytic hydrogenolysis of natural rubber. Ultimately, various rubber wastes were directly converted to natural gas, it could provide a new perspective for the chemical upcycling of the accumulated rubber wastes.

Reversibly Cross-Linked Isoporous Membranes Fabricated by the Recyclable Block Copolymer with Pendent Dithiolane Groups.

The reversible formation and cleavage of disulfide bonds under physical/chemical stimuli make it a valuable motif in constructing dynamically cross-linked materials. In the present work, the block copolymer bearing pendent dithiolanes was synthesized and fabricated into isoporous membranes by the combination of self-assembly and nonsolvent-induced phase separation strategy. The cross-linking within the membrane was realized by the thiol-initiated ring-opening cascades of cyclic disulfides. Successful formation of disulfide bond networks within the isoporous membranes was proved by the Raman spectra, UV-vis diffuse reflectance spectroscopy, differential scanning calorimetry, and rheological analysis. The cross-linking in membranes was further demonstrated by the notably improved toughness and obviously enhanced swelling resistance to acid/alkaline solution as well as organic solvents. Importantly, the cross-linked isoporous membranes were fully dissolvable in solution containing dithiothreitol, which enabled the complete cleavage of disulfide bonds and successful recovery of the block copolymer that was able to be repeatedly fabricated into isoporous membranes with pore sizes identical to membranes prepared from the freshly synthesized copolymer. Our results indicate that dynamically cross-linked isoporous membranes with improved durability and good recyclability can be custom-made by simply incorporating active dithiolane moieties into self-assembling block copolymers.

Mineralogical characteristics and fluid inclusions of the Dashuixiabei crystalline graphite deposit in the Dunhuang block

AbstractGraphite is a strategic mineral resource of the world. The Dashuixiabei (DSXB) crystalline graphite deposit is located in the Dongbatu area in the Altyn crystalline graphite metallogenic belt. This study presents data from x‐ray diffraction (XRD), scanning electron microscopy (SEM), laser Raman spectroscopy, and fluid inclusions analysis conducted on the DSXB crystalline graphite deposit. The graphite is flake shaped, with a diameter of 0.1–0.4 mm. A group of extremely complete cleavage was observed under SEM, and the overall distribution was a flake. The C content in graphite is greater than 90 wt%, followed by N, O, and so on. The results of XRD analysis show that the lattice parameters of the DSXB crystalline graphite is a = 0.246–0.2465 nm, c = 0.6714–0.6715 nm, and V = 0.03519–0.03532 nm3. The degree of graphitization ranges from 0.8490 to 0.8519, indicating that the graphite crystal structure is relatively intact, the average metamorphic temperature is 552°C, and the content of 3R polytypes ranges from 13.16% to 13.25%. It is concluded that the metamorphic rocks of the DSXB crystalline graphite deposit have undergone medium‐grade metamorphism. The Raman spectral peaks show that DSXB crystalline graphite has a high degree of crystallinity. The DSXB crystalline graphite ore is dominated by hydrothermal fluids with medium‐low temperature and medium‐low salinity, and the vapor phase of the fluid inclusions is composed of CH4. There may be a superposition of the main and secondary mineralization stages. The crystalline graphite from the DSXB deposit shows high quality and stable ore quality, which has good metallogenic conditions and development and utilization prospects.

N[double bond, length as m-dash]N bond cleavage in diazirines by a cyclic diborane(4) compound.

Reactions of o-carborane-fused diborane(4) with 3H-diazirines led to the complete cleavage of the N[double bond, length as m-dash]N bond, with one nitrogen atom being incorporated into the B-B bond. The molecular and electronic structures of the resultant borylnitrogen compounds were confirmed through single-crystal X-ray analyses and computational studies. The related reaction mechanism was investigated using DFT calculations.

Directed Circularization of a Short RNA.

Basic research and functional analyses of circular RNA (circRNA) have been limited by challenges in circRNA formation of desired length and sequence in adequate yields. Nowadays, circular RNA can be obtained using enzymatic, "ribozymatic," or modulated splice events. However, there are few records for the directed circularization of RNA. Here, we present a proof of principle for an affordable and efficient RNA-based system for the controlled synthesis of circRNA with a physiological 3',5'-phosphodiester conjunction. The engineered hairpin ribozyme variant circular ribozyme 3 (CRZ-3) performs self-cleavage poorly. We designed an activator-polyamine complex to complete cleavage as a prerequisite for subsequent circularization. The developed protocol allows synthesizing circRNA without external enzymatic assistance and adds a controllable way of circularization to the existing methods.

Alkyl, aryl and hetaryl acetylenes - highly reactive multifunctional compounds (a review)

The author’s data (2000-2022) on synthesis methods, reactivity and applied aspects of aryl- and hetarylacetylenes were summarized. The specificity of alkynylarenes (hetarenes) associated with the activation of the triple bond by acceptor groups were noted. Particular attention was paid to fundamentally important new reactions of heterocyclization and complete soft cleavage of the triple bond. The prospects for the use of alkynylarenes and -hetarenes and their modification products were reflected. The results of screening of the synthesized compounds were presented.

Efficient degradation of imidacloprid by surface discharge cold plasma: Mechanism of interaction between ROS and molecular structure and evaluation of residual toxicity

Incorrect use of neonicotinoid pesticides poses a serious threat to human and pollinator health, as these substances are commonly present in bee products and even drinking water. To combat this threat, the study developed a new method of degrading the pesticide imidacloprid using surface discharge cold plasma oxidation technology. The study showed that this method achieved a very high efficiency of imidacloprid degradation of 91.4%. The main reactive oxygen species (H2O2, O3, ·OH, O2-, 1O2) effectively participated in the decomposition reaction of imidacloprid. Reactive oxygen species were more sensitive to the structure of the nitroimine group. Density functional theory (DFT) further explored the sites of reactive oxygen species attack on imidacloprid and revealed the process of energy change of attacking imidacloprid. In addition, a degradation pathway for imidacloprid was proposed, mainly involving reactive oxygen species chemisorption, a ring-opening intermediate, and complete cleavage of the nitroimine group structure. Model predictions indicated that acute oral and developmental toxicity were significantly reduced after cold plasma treatment, as confirmed by insect experiments. Animal experiments have shown that plasma treatment reduces imidacloprid damage to mice hippocampal tissue structure and inhibits the reduction of brain-derived neurotrophic factor content, thus revealing the detoxification mechanism of the body.

Titin governs myocardial passive stiffness with major support from microtubules and actin and the extracellular matrix.

Myocardial passive stiffness is crucial for the heart's pump function and is determined by mechanical elements, including the extracellular matrix and cytoskeletal filaments; however, their individual contributions are controversially discussed and difficult to quantify. In this study, we targeted the cytoskeletal filaments in a mouse model, which enables the specific, acute and complete cleavage of the sarcomeric titin springs. We show in vitro that each cytoskeletal filament's stiffness contribution varies depending on whether the elastic or the viscous forces are considered and on strain level. Titin governs myocardial elastic forces, with the largest contribution provided at both low and high strain. Viscous force contributions are more uniformly distributed among the microtubules, titin and actin. The extracellular matrix contributes at high strain. The remaining forces after total target element disruption are likely derived from desmin filaments. Our findings answer longstanding questions about cardiac mechanical architecture and allow better targeting of passive myocardial stiffness in heart failure.

Selective Cleavage of Methylene Linkage in Kraft Lignin over Commercial Zeolite in Isopropanol.

Lignin is an aromatic polymer that constitutes over 30 wt% of lignocellulosic biomass and is the most important source of renewable aromatics in nature. The global paper industry generates more than 70 million tons of Kraft lignin annually. Depolymerization of Kraft lignin to value-added monomers can significantly enhance the profitability of biorefinery. However, the method is impeded by the severe condensation of Kraft lignin during the pulping process, which forms robust C-C bonds and results in low monomer yields. In this study, we present a stepwise approach for producing valuable aromatic monomers from Kraft lignin through the cleavage of both C-O and C-C bonds. The approach initiated with complete cleavage of C-O bonds between lignin units within Kraft lignin through alcoholysis in isopropanol, resulting in a monomer yield of 8.9 %. Subsequently, the selective cleavage of methylene linkages present in the residual dimers and oligomers was achieved with commercial MCM-41 zeolite in the same pot, proceeding with an additional monomer yield of 4.0 %, thereby increasing the total monomer yield by 45 %. This work provides an avenue for increasing the depolymerization efficiency of Kraft lignin.

Degradation Kinetics of Disulfide Cross-Linked Microgels: Real-Time Monitoring by Confocal Microscopy.

Although biodegradable microgels represent a useful drug delivery system, questions remain regarding the kinetics of gel degradation and subsequent drug release. Spherical microgels (~Ø10-300 µm) were synthesized using an inverse suspension polymerization method. Specifically, acrylamide and acrylonitrile monomers were thermally co-polymerized with N,N'-bis(acryloyl)cystamine as a cross-linker with disulfide bridges. The kinetics and mechanism of degradation of these cross-linked, degradable, fluorescently labeled microgels (PAAm-AN-BAC-FA) were quantitatively studied under confocal microscopy at various concentrations of glutathione (reducing agent) ranging from 0.06 to 91.8 mM. It was found that polymer network degradation via the cleavage of disulfide bonds was accompanied by two overlapping processes: diffusion-driven swelling and dissolution-driven erosion. A slow increase in microgel size (swelling) resulted from partial de-cross-linking in the bulk of the microgel, whereas a faster decrease in fluorescence intensity (erosion) resulted from the complete cleavage of disulfide bonds and the release of uncleaved polymeric chains from the microgel immediate surface into the solution. Swelling and erosion exhibited distinct kinetics and characteristic times. Importantly, the dependence of kinetics on glutathione concentration for both swelling and erosion suggests that degradation would occur faster in cancer cells (higher concentration of reductants) than in normal cells (lower concentration of reductants), such that drug release profiles would be correspondingly different. A greater comprehension of microgel degradation kinetics would help in (i) predicting the drug release profiles for novel multifunctional drug delivery systems and (ii) using redox-sensitive degradable hydrogel particles to determine the concentrations of reducing agents either in vitro or in vivo.

Double Bond Cleavage in Small Molecules Using a Geminal Sc/P Lewis Pair.

Frustrated Lewis pairs (FLPs) have proven capable of cleaving the H-H σ-bond and binding a variety of unsaturated small molecules. In contrast, examples of FLP-mediated complete rupture of double-bonded substrates remain scarce. Herein, we present a geminal Sc/P Lewis pair, i.e., (ArO)2ScN(tBu)PPh2 (Ar = 2,6-tBu2-C6H3), that exhibits typical FLP-type 1,2-addition reactivity toward CO2. Notably, it enables the complete cleavage of a series of double bonds, such as the N═N bond in azobenzene or pyridazine, the N═O bond in nitrosobenzene, and the N═S and S═O bonds in N-sulfinylaniline, to yield the corresponding metallacyclic products. Moreover, the first rare-earth metal sulfur monoxide adduct could be obtained through the bond cleavage of PhNSO, demonstrating the capability of rare-earth metal complexes to capture reactive species.

Ni-catalyzed carbon–carbon bonds cleavage of mixed polyolefin plastics waste

The inert carbon–carbon (C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickel-based catalyst involving Ni2Al3 phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier. Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.

DEVELOPMENT OF A METHOD FOR PRODUCING FAB/F(AB’)2 FRAGMENTS FROM A FULL-LENGTH MONOCLONAL ANTIBODY FOR BIOANALYTICAL ASSAYS

Abstract Background Monoclonal antibodies (mAb) comprise of two Fab fragments and one Fc fragment or one F(ab)’2 fragment and one Fc fragment. While a full-length mAb is frequently used as an assay reagent for bioanalysis, mAb fragments are required in certain cases. For example, to build a sandwich assay for detection of anti-drug antibodies (ADA) for therapeutic antibodies, Fab or F(ab)’2 fragment is used instead of a full-length mAb as capture reagent. This is because therapeutic antibodies, either humanized or fully human, are in many ways indistinguishable from the ADA generated in patients, especially in Fc fragment. When ADA detection methods utilizes anti-human Fc antibodies as the detection reagent, the full-length mAb drug will be directly bound by the detection reagent, causing interference. Preparation of a Fab or F(ab)’2 fragment is therefore needed. Methods and results We are developing a method for enzymatic digestion of therapeutic antibodies to generate monovalent Fab or bivalent F(ab’)2 fragments in this study. With such reagents becoming available, a sandwich ADA assay formats can be expanded to allow anti-human Fc antibodies as detection regents. To standardize the method, we explored various enzymatic conditions, including type of enzymes (i.e., pepsin, papain, and IdeS Protease), digestion-time (1, 2, 4, and 6 h), enzyme to antibody ratio (1:10, 1:20, and 1:40 w/w), IgG species and isotypes (human IgG1-κ, IgG1-λ, and IgG4-κ). The enzymatic hydrolysates were quantified by NanoDrop and purified by dialysis (10K MWCO) and Protein A/G/L magnetic bead methods. The effective recovery of truncated antibodies was > 90%, as assessed by reduced/non-reduced SDS-PAGE and ELISA analysis. Digestion of human IgG1 and IgG4 with pepsin resulted into a complete cleavage into F(ab')2 fragments and degradation of Fc fragments. While IdeS Protease produced an equivalent quantity of F(ab’)2 and Fc fragments with a similar efficiency, removal of the intact Fc fragment was required as an additional step. If the Fab fragments were desired, papain could be used with yield being over 90%. We have subsequently utilized either Fab or F(ab’)2 as a capture reagent for ADA detection. Conclusion We have successfully developed the enzymatic digestion method to prepare Fab or F(ab’)2 fragments. The optimized conditions described here are broadly applicable to different IgG isotypes across many therapeutic antibodies.

Microstructure and mechanical properties of suction-cast aluminium–cerium alloys

ABSTRACT In the present investigation, the microstructure and tensile properties of Al–12Ce, Al–12Ce–4Si, and Al–12Ce–4Si–0.4Mg alloys (wt-%), fabricated by suction-casting (SC) and gravity-casting (GC) were compared. The SC alloys exhibited finer grains and a higher number of precipitates than the GC alloys. Addition of Si and Mg in Al–12Ce alloy improved the hardness substantially. Incorporation of 4Si and 0.4Mg enhanced the yield and tensile stress but reduced ductility in the SC alloys. The SC Al-12Ce-4Si-0.4Mg alloy illustrated the best hardness and tensile strength. The fracture behaviour of the SC Al–12Ce alloy changed from quasi-cleavage to complete cleavage fracture following the addition of 4Si and 0.4Mg.

Interaction of Aluminum and Platinum Surfaces with the Ionic Liquids 1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

The processes at the interface between ionic liquids (ILs) and metals are a key factor for understanding especially in electrochemical deposition, nanoscale tribology applications and batteries. In the present work, the interfaces of 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Py1,4]TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm]TFSI) and platinum and aluminum were investigated by depositing thin IL films and studying them with X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum. It is found that there is no evidence of a decomposition reaction of either IL on platinum; however, the imidazolium cation of [EMIm]TFSI shows a strong interaction with the surface in the monolayer regime. In contrast, [Py1,4]TFSI and [EMIm]TFSI show massive decomposition on the aluminum surface without applying any electrochemical potential. The spectra for the [TFSI]− anion components show cleavage of C-F or N-S bonds in both cases. Both cleavage of a single fluorine atom and complete cleavage were observed, leading to further decomposition reactions of the anion. Consequently, new components such as AlOOH, Al(OH)3, Al2S3, Al2(SO4)3 and AlF3 appear at the interface. In addition, there is also evidence of decomposition of the cation by the splitting off hydrogen atoms or parts of the alkyl chain in both ILs.

P-296 Supernumerary blastocysts resulting from abnormal cleavage patterns: freeze or not to freeze? A practical question!

Abstract Study question After eSET, the supernumerary blastocysts that showed cleavage anomalies can be vitrified as second choice embryos. Do they display enough implantation chance to be frozen? Summary answer No pregnancy was obtained after frozen transfer of blastocysts with direct uneven cleavage and chaotic cleavage. It is not recommended to freeze those spare embryos. What is known already The use of time-lapse incubation offers stable culture conditions and provides comprehensive information on dynamic embryo development. Studies found that abnormal cleavage affects the genome of human embryos and can reduce its developmental potential with embryonic arrest. Aneuploidy contributes also to failed implantation. It was also reported that cleavage anomalies such as direct uneven cleavage and chaotic cleavage affect negatively implantation and live birth. Even if the good survival rate of blastocysts after vitrification has dramatically improved clinical outcome after frozen embryo transfer, implantation and live birth are correlated to embryonic ploidy and healthy cellular machinery. Study design, size, duration Retrospective qualitative assessment of time-lapse images for 186 vitrified blastocysts resulting from extended culture of 871 embryos showing morphokinetic abnormalities such as direct uneven cleavage first mitosis (DC1), direct cleavage second mitosis (DC2), fast cleavage (FC), complete chaotic cleavage (CC) and multiple anomalies (MA), during 2021-2022 in a single private hospital, and analysis of the clinical outcome after warming and SET. Participants/materials, setting, methods From 871 embryos in Embryoscope + (Vitrolife), 445 total blastocysts and 251 top quality were obtained according to Gardner’s grading. 186 of those were vitrified for further transfer. In 5 subgroups of anomalies (DC1, DC2, FC, CC, MA) pregnancy (PR) and ongoing pregnancy rate (OPR) per warming cycle and per transfer were calculated. The results were compared by SPSS software to overall 2021 center’s results. Main results and the role of chance The mean female age was 35.4 ± 0.5 years. From the 186 top quality blastocysts that were vitrified, 96 were warmed in 94 frozen cycles with a survival rate of 98.3%, resulting in 93 SET transfers. A total of 32 pregnancies were obtained from which 21 were ongoing pregnancies. There was no statistical difference in PR per warming cycle or per transfer, and in OPR per warming cycle or per transfer between the overall study group compared to the center’s annual results 2021: 34.0% vs 40.2%, 34.4% vs 40.1%, 22.3% vs 30.1%, and 22.6% vs 30.7%. Reasonable PR and OPR per transfer were obtained with blastocysts from DC2, FC and MA patterns, with caution to small sample size: 32.0% and 20.0%, 44.1% and 32.3%, 40.0% and 25.0%. The results were statistically comparable to the center’s annual result. All the transfers from DC1 and CC pattern failed to achieve a pregnancy. Limitations, reasons for caution One limitation of the study was its retrospective nature and the other was the small sample size in each subgroup of anomaly. The results should be confirmed prospectively and should compel the live birth rate after delivery of the ongoing pregnancies obtained during the second semester of 2022. Wider implications of the findings Abnormal cleavage patterns such as DC and CC are known to affect negatively implantation and live birth. Deselection of embryos showing these specific patterns could significantly increase successful implantation for the accordingly selected embryos. It is therefore non optimal to freeze the spare blastocysts resulting from these peculiar abnormal patterns. Trial registration number NA

Biogeochemical behavior and ecological environmental effects of fluoroquinolones.

Synthetic fluoroquinolones (FQs) are the third most commonly used antibiotics in the world and play an extremely important role in antibacterial drugs. The excessive use and discharge will alter ecological environment, with consequence on human health and global sustainable development. It is therefore of great significance for scientific use and management of FQs to systematically understand their biogeochemical behavior and eco-environmental effects. After drug administration in humans and animals, only a small part of FQs are transformed in vivo. The main transformation processes include formylation, acetylation, oxidation and cleavage of piperazine ring, defluorination and decarboxylation of aromatic core ring, etc. About 70% of the original drug and a small amount of transformed products would be migrated to the environment through excretion. After entering the environment, FQs and their transformation products mainly exist in environmental media such as water, soil and sediment, and undergo migration and transformation processes such as adsorption, photolysis and biodegradation. Adsorption facilitates transfer of FQs from medium to another. The photolysis mainly affects the C7-amine substituents of FQs, whereas the core structure of FQs remains intact. Biodegradation mainly refers to the degradation of FQs by microorganisms and microalgae, including piperazine modification of the piperazine ring such as acetylation and formylation, partial or complete ring cleavage, core structure decarboxylation, defluorination and conjugation formation. The migration and transformation processes of FQs cannot completely eliminate them from the environment. Instead, they would become "pseudo-persistent" pollutants, which seriously affect the behavior, growth and reproduction of algae, crustaceans and fish, change biogeochemical cycle, destroy aquatic environment, and stimulate microbial resistance and the generation of resistance genes. In the future, more in-depth studies should be conducted on the environmental behavior of FQs and their impacts on ecological environment, the risk assessment of microbial resistance and resistance genes of FQs, and the mechanism and effect of micro-biodegradation of FQs.