Direct Oxidative Cyclization of 3-Arylpropionic Acids to 3,4-Dihydrocoumarins: Reinvestigation of the Reaction Mechanism.

Instigated by olfactory analysis of odorant molecules, the constitutions of 3,4-dihydrocoumarins prepared by PIFA-based oxidative cyclizations of 3-arylpropionic acids were revised by means of 2D NMR and X-ray analysis. Supported by computational analysis, the migratory mechanism of intermediate spirolactonic cations has been amended: 1,2-alkyl shifts instead of 1,2-carboxylic shifts were selectively obtained.

The underlying molecular mechanism of ciliated epithelium dysfunction and TGF-ß signaling in children with congenital pulmonary airway malformations.

The aim of this study was to investigate the variation in gene expression in the complete transcripts of Congenitalpulmonary airwaymalformation (CPAM) of the lung using Next Generation Sequencing (NGS) technology. There were 20 cases involving children with CPAM were used for selection of study sample. NGS was used to establish RNA-Seq libraries for the two groups of samples separately, and both groups were conducted to differential expression analysis and Gene Ontology (GO) functional enrichment analysis. The pathways of the differential genes were analyzed to find the enriched target pathways. A total of 592 genes were expressed with significant differences (CPAM vs. normal tissue, P < 0.05). GO functional analysis of DEGs indicated that abnormal ciliary function played a role in the development of CPAM. Subsequently, analysis of these genes pathways showed the TGF-ß signaling pathway was significantly enriched. Finally, the results of immunohistochemical analysis of some DEGs showed that a significant reduction in the expression of SMAD6, a gene related to the TGF-ß signaling pathway, led to abnormal activation of the pathway. TGF-ß signaling pathway involved in the evolution of the disease obtained by DEGs enrichment pathway analysis. SMAD6, a gene involved in this pathway, might be a potential biomarker for the diagnosis and treatment of CPAM.

Qualitative Proteome-wide Lysine Crotonylation Profiling Reveals Protein Modification Alteration in the Leukocyte Extravasation Pathway in Systemic Lupus Erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is a severe systemic autoimmune disease with multiple manifestations. Lysine crotonylation (Kcr) is a newly discovered posttranslational modification epigenetic pattern that may affect gene expression and is linked to diseases causally. METHODS: We collected blood samples from 11 SLE individuals and 36 healthy subjects. Then, we used highly sensitive liquid chromatography-mass spectrometry technology to carry out proteomics and quantitative crotonylome analysis of SLE peripheral blood mononuclear cells in this investigation, which indicated the unique etiology of SLE. Finally, we verified the expression of critical protein in the leukocyte extravasation pathway by online database analysis and Western blot. RESULTS: There were 618 differentially expressed proteins (DEPs), and 612 crotonylated lysine sites for 272 differentially modified proteins (DMPs) found. These DEPs and DMPs are primarily enriched in the leukocyte extravasation signaling pathway, such as MMP8, MMP9, and ITGAM. CONCLUSIONS: This is the first study of crotonylated modification proteomics in SLE. The leukocyte extravasation signaling pathway had a considerable concentration of DEPs and DMPs, indicating that this pathway may be involved in the pathogenic development of SLE.

Identification of a novel ferroptosis-related gene signature associated with retinal degeneration induced by light damage in mice.

Background: Neurodegenerative retinal diseases such as retinitis pigmentosa are serious disorders that may cause irreversible visual impairment. Ferroptosis is a novel type of programmed cell death, and the involvement of ferroptosis in retinal degeneration is still unclear. This study aimed to investigate the related ferroptosis genes in a mice model of retinal degeneration induced by light damage. Methods: A public dataset of GSE10528 deriving from the Gene Expression Omnibus database was analyzed to identify the differentially expressed genes (DEGs). Gene set enrichment analysis between light damage and control group was conducted. The differentially expressed ferroptosis-related genes (DE-FRGs) were subsequently identified by intersecting the DEGs with a ferroptosis genes dataset retrieved from the FerrDb database. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were further performed using the DE-FRGs. A protein-protein interaction (PPI) network was constructed to identify hub ferroptosis-related genes (HFRGs). The microRNAs (miRNAs)-HFRGs, transcription factors (TFs)-HFRGs networks as well as target drugs potentially interacting with HFRGs were analyzed utilizing bioinformatics algorithms. Results: A total of 932 DEGs were identified between the light damage and control group. Among these, 25 genes were associated with ferroptosis. GO and KEGG analyses revealed that these DE-FRGs were mainly enriched in apoptotic signaling pathway, response to oxidative stress and autophagy, ferroptosis, necroptosis and cytosolic DNA-sensing pathway. Through PPI network analysis, six hub ferroptosis-related genes (Jun, Stat3, Hmox1, Atf3, Hspa5 and Ripk1) were ultimately identified. All of them were upregulated in light damage retinas, as verified by the GSE146176 dataset. Bioinformatics analyses predicated that 116 miRNAs, 23 TFs and several potential therapeutic compounds might interact with the identified HFRGs. Conclusion: Our study may provide novel potential biomarkers, therapeutic targets and new insights into the ferroptosis landscape in retinal neurodegenerative diseases.

Dysregulated Arginine Metabolism Is Linked to Retinal Degeneration in Cep250 Knockout Mice.

Purpose: Degeneration of retinal photoreceptors is frequently observed in diverse ciliopathy disorders, and photoreceptor cilium gates the molecular trafficking between the inner and the outer segment (OS). This study aims to generate a homozygous global Cep250 knockout (KO) mouse and study the resulting phenotype. Methods: We used Cep250 KO mice and untargeted metabolomics to uncover potential mechanisms underlying retinal degeneration. Long-term follow-up studies using optical coherence tomography (OCT) and electroretinography (ERG) were performed. Results: OCT and ERG results demonstrated gradual thinning of the outer nuclear layer (ONL) and progressive attenuation of the scotopic ERG responses in Cep250-/- mice. More TUNEL signal was observed in the ONL of these mice. Immunostaining of selected OS proteins revealed mislocalization of these proteins in the ONL of Cep250-/- mice. Interestingly, untargeted metabolomics analysis revealed arginine-related metabolic pathways were altered and enriched in Cep250-/- mice. Mis-localization of a key protein in the arginine metabolism pathway, arginase 1 (ARG1), in the ONL of KO mice further supports this model. Moreover, adeno-associated virus (AAV)-based retinal knockdown of Arg1 led to similar architectural and functional alterations in wild-type retinas. Conclusions: Altogether, these results suggest that dysregulated arginine metabolism contributes to retinal degeneration in Cep250-/- mice. Our findings provide novel insights that increase understanding of retinal degeneration in ciliopathy disorders.

Image-Guided Optical Coherence Tomography to Assess Structural Changes in Rodent Retinas.

Ocular diseases, such as age-related macular degeneration, glaucoma, retinitis pigmentosa, and uveitis, are always accompanied by retinal structural changes. These diseases affecting the fundus always exhibit typical abnormalities in certain cell types in the retina, including photoreceptor cells, retinal ganglion cells, cells in the retinal blood vessels, and cells in the choroidal vascular cells. Noninvasive, highly efficient, and adaptable imaging techniques are required for both clinical practice and basic research. Image-guided optical coherence tomography (OCT) satisfies these requirements because it combines fundus photography and high-resolution OCT, providing an accurate diagnosis of tiny lesions as well as important changes in the retinal architecture. This study details the procedures of data collection and data analysis for image-guided OCT and demonstrates its application in rodent models of choroidal neovascularization (CNV), optic nerve crush (ONC), light-induced retinal degeneration, and experimental autoimmune uveitis (EAU). This technique helps researchers in the eye field to identify rodent retinal structural changes conveniently, reliably, and tractably.

Application of second-generation sequencing in congenital pulmonary airway malformations.

To investigate the differential expression of genes in whole transcripts of congenital pulmonary airway malformation (CPAM) using second-generation sequencing (also known as next-generation sequencing, NGS) technology. Children with CPAM were strictly screened after setting the criteria, and grouped by taking CPAM parietal tissue and CPAM lesion tissue respectively, and RNA-Seq libraries were established separately using second-generation sequencing technology, followed by differential expression analysis and GO (gene ontology) functional enrichment analysis, KEGG (Kyoto encyclopedia of genes and genomes, a database) pathway analysis and GSEA (Gene Set Enrichment Analysis) analysis. Five cases were screened from 36 children with CPAM, and high-throughput sequencing was performed to obtain 10 whole transcripts of samples with acceptable sequence quality and balanced gene coverage. One aberrantly expressed sample (3b) was found by analysis of principal components, which was excluded and then subjected to differential expression analysis, and 860 up-regulated genes and 203 down-regulated genes. GO functional enrichment analysis of differentially expressed genes demonstrates the functional class and cellular localization of target genes. The whole transcript of CPAM shows obvious gene up and down-regulation, differentially expressed genes are located in specific cells and belong to different functional categories, and NGS can provide an effective means to study the transcriptional regulation of CPAM from the overall transcriptional level.

Clinical Image Feature Analysis and Diagnostic Efficacy Evaluation of Pulmonary Ultrasound in the Diagnosis of Congenital Pulmonary Airway Malformations in Children: Based on a Single Center, Retrospective Cohort Study.

Objective: A single center, retrospective cohort study was conducted to analyze the clinical image features and diagnostic efficiency of pulmonary ultrasound in the diagnosis of congenital pulmonary airway malformations (CPAMs) in children. Methods: The starting and ending time of this study is from May 2019 to December 2021. This study included 200 children with CPAM diagnosed by prenatal ultrasound and postpartum CT imaging (aged from 1 hour to 3 years), including 103 males and 97 females. All of them were diagnosed by fetal ultrasound and were examined by chest X-ray (CXR), chest CT, and lung ultrasound (LUS). The clinical image characteristics and diagnostic efficiency of CXR, chest CT, and LUS in the diagnosis of CPAM in children were analyzed. Results: 200 lesions were limited to single lung, and the most common were right lower lobe, right lower lobe in 80 cases (40.0%), left lower lobe in 60 cases (30.0%), right upper lobe in 30 cases (15.0%), left upper lobe in 20 cases (10.0%), and right middle lobe in 10 cases (5.0%). Among the 200 cases of preoperative CT examination, 196 cases (98.00%) showed lesions and confirmed diagnosis, and 4 cases were missed. Chest X-ray showed multiple focal circular low-density shadow in the right lung, and the heart shadow and mediastinum moved slightly to the left. CXR showed multiple cystic transparent shadows in the left lower lung and slightly to the right of the mediastinum and heart. CXR showed multiple balloon cavities of different sizes in the right lung field, and the mediastinum and heart shadow shifted to the left. The direct signs of LUS (including single or multiple cystic lesions) were not significantly different from those of CXR, but the indirect signs were significantly higher than those of CXR. Conclusion: The most common CT findings of CPAM in children are cystic lesions, especially polycystic lesions, while LUS images of CPAM in children are various. LUS is a noninvasive and nonradiological examination method, which is easy to operate and repeat. LUS can be used for preliminary qualitative screening of CPAM in children, and the diagnostic value of indirect signs of LUS is better than that of CXR.

Depletion of miR-96 Delays, But Does Not Arrest, Photoreceptor Development in Mice.

Purpose: Abundant retinal microRNA-183 cluster (miR-183C) has been reported to be a key player in photoreceptor development and functionality in mice. However, whether there is a protagonist in this cluster remains unclear. Here, we used a mutant mouse model to study the role of miR-96, a member of miR-183C, in photoreceptor development and functionality. Methods: The mature miR-96 sequence was removed using the CRISPR/Cas9 genome-editing system. Electroretinogram (ERG) and optical coherence tomography (OCT) investigated the changes in structure and function in mouse retinas. Immunostaining determined the localization and morphology of the retinal cells. RNA sequencing was conducted to observe retinal transcription alterations. Results: The miR-96 mutant mice exhibited cone developmental delay, as occurs in miR-183/96 double knockout mice. Immunostaining of cone-specific marker genes revealed cone nucleus mislocalization and exiguous Opn1mw/Opn1sw in the mutant (MT) mouse outer segments at postnatal day 10. Interestingly, this phenomenon could be relieved in the adult stages. Transcriptome analysis revealed activation of microtubule-, actin filament-, and cilia-related pathways, further supporting the findings. Based on ERG and OCT results at different ages, the MT mice displayed developmental delay not only in cones but also in rods. In addition, a group of miR-96 potential direct and indirect target genes was summarized for interpretation and further studies of miR-96-related retinal developmental defects. Conclusions: Depletion of miR-96 delayed but did not arrest photoreceptor development in mice. This miRNA is indispensable for mouse photoreceptor maturation, especially for cones.

AMnAs3S6 (A = Cs, Rb): Phase-Matchable Infrared Nonlinear Optical Functional Motif [As3S6]3- Obtained via Surfactant-Thermal Method.

Exploration of a new nonlinear optical (NLO)-active functional motif is important in the rational design of promising infrared (IR) NLO materials. Compared with typical tetrahedral MQ4 (M = IIB, III, IV metals; Q = S, Se) motifs, MQ3 (M = As, Sb) pyramids favor high second-harmonic generation (SHG) efficiency while frequently hindering phase matching (PM) because of excessively large optical anisotropy. The surfactant-thermal method was first adopted to achieve PM in MQ3-containing systems and synthesize mixed covalent-ionic IR NLO materials. Two new thioarsenates of AMnAs3S6 (A = Cs, Rb) exhibiting strong PM SHG efficiencies comparable to commercial AGS and laser-induced damage thresholds of one order higher than AGS were obtained. The [As3S6]3- unit in their structures is an unprecedented NLO-active functional motif, which can be useful in designing new IR NLO compounds with large SHG efficiency. In addition, the surfactant-thermal method provides a new general strategy for synthesizing new IR NLO materials.

[ABa2Cl][Ga4S8] (A = Rb, Cs): Wide-Spectrum Nonlinear Optical Materials Obtained by Polycation-Substitution-Induced Nonlinear Optical (NLO)-Functional Motif Ordering.

Noncentrosymmetry (NCS) is a prerequisite for second-order nonlinear optical (NLO) materials. In this work, a new polycation-substitution-induced centrosymmetry (CS)-to-NCS transformation strategy was applied in CS RbGaS2, affording two novel NCS salt-inclusion chalcogenides: [ABa2Cl][Ga4S8] (A = Rb, 1; Cs, 2). Remarkably, they exhibit the key merits of both Vis and IR NLO candidates, including strong phase-matchable second harmonic generation intensities (10.4-15.3 × KH2PO4 at 1064 nm; 0.9-1.0 × AgGaS2 at 1910 nm), high laser-induced damage thresholds (11-12 × AgGaS2), and a wide transparent window. Their prominent NLO performances originate from the orderly packing of T2-supertetrahedral Ga4S10 motifs resulting from the template effect of acentric polycation [ClA2Ba3]7+. The CS-to-NCS transformation first realized by polycation-substitution-induced NLO-functional motif ordering provides an effective approach for designing new NLO materials.

Li[LiCs2 Cl][Ga3 S6 ]: A Nanoporous Framework of GaS4 Tetrahedra with Excellent Nonlinear Optical Performance.

A large nonlinear optical (NLO) coefficient and a wide band gap are two crucial but contradictory parameters that are difficult to achieve simultaneously in a single infrared (IR) NLO compound. A salt-inclusion chalcogenide (SIC), Li[LiCs2 Cl][Ga3 S6 ] (1), was prepared that presents a nanosized tunnel framework constructed from monotype chalcogenide tetrahedra. Highly oriented covalent GaS4 tetrahedra in the host lead to a moderate second harmonic generation response (0.7 AgGaS2 ), and ionic guests effectively broaden the band gap to the widest value (4.18 eV) among all IR NLO chalcogenides, thereby achieving a remarkable balance between NLO efficiency and band gap.

New strategy for designing promising mid-infrared nonlinear optical materials: narrowing the band gap for large nonlinear optical efficiencies and reducing the thermal effect for a high laser-induced damage threshold.

To circumvent the incompatibility between large nonlinear optical (NLO) efficiencies and high laser-induced damage thresholds (LIDTs) in mid-infrared NLO materials, a new strategy for designing materials with both excellent properties is proposed. This strategy involves narrowing the band gap for large NLO efficiencies and reducing the thermal effect for a high LIDT. To support these proposals, a series of isostructural chalcogenides with various tetrahedral center cations, Na2Ga2MQ6 (M = Ge, Sn; Q = S, Se), were synthesized and studied in detail. Compared with the benchmark AGS, these chalcogenides exhibit significantly narrower band gaps (1.56-1.73 eV, AGS: 2.62 eV) and high NLO efficiencies (1.6-3.9 times that of AGS at 1910 nm), and also outstanding LIDTs of 8.5-13.3 × those of AGS for potential high-power applications, which are contrary to the conventional band gap view but can be attributed to their small thermal expansion anisotropy, surmounting the NLO-LIDT incompatibility. These results shed light on the search for practical IR NLO materials with excellent performance not restricted by NLO-LIDT incompatibility.

Strong Infrared Nonlinear Optical Efficiency and High Laser Damage Threshold Realized in Quaternary Alkali Metal Sulfides Na2Ga2MS6 (M = Ge, Sn) Containing Mixed Nonlinear Optically Active Motifs.

Two new infrared (IR) nonlinear optical (NLO) sulfides, Na2Ga2GeS6 and Na2Ga2SnS6, were obtained by mixing different typical NLO-active motifs GaS4 and GeS4/SnS4 in the alkali metal-containing system. The IR NLO sulfides present laser-induced damage thresholds that are 18.1 and 17.9 times that of the reference AgGaS2 (AGS) and second-harmonic generation efficiencies that are 0.8 and 1.1 times that of AGS. These properties originate from the GaS4, GeS4, and SnS4 tetrahedral blocks in the structures of the sulfides. Both compounds also exhibit a broad transparency range and type-I phase-matching behavior, which support their high potential in high-power laser applications. This work sheds new light on the development of promising mid-IR NLO materials by combining different NLO-active motifs.

Detecting the Presence of Bacterial DNA and RNA by Polymerase Chain Reaction to Diagnose Suspected Periprosthetic Joint Infection after Antibiotic Therapy.

OBJECTIVE: To explore the diagnostic efficiency of DNA-based and RNA-based quantitative polymerase chain reaction (qPCR) analyses for periprosthetic joint infection (PJI). METHODS: To determine the detection limit of DNA-based and RNA-based qPCR in vitro, Staphylococcus aureus and Escherichia coli strains were added to sterile synovial fluid obtained from a patient with knee osteoarthritis. Serial dilutions of samples were analyzed by DNA-based and RNA-based qPCR. Clinically, patients who were suspected of having PJI and eventually underwent revision arthroplasty in our hospital from July 2014 to December 2016 were screened. Preoperative puncture or intraoperative collection was performed on patients who met the inclusion and exclusion criteria to obtain synovial fluid. DNA-based and RNA-based PCR analyses and culture were performed on each synovial fluid sample. The patients' demographic characteristics, medical history, and laboratory test results were recorded. The diagnostic efficiency of both PCR assays was compared with culture methods. RESULTS: The in vitro analysis demonstrated that DNA-based qPCR assay was highly sensitive, with the detection limit being 1200 colony forming units (CFU)/mL of S. aureus and 3200 CFU/mL of E. coli. Meanwhile, The RNA-based qPCR assay could detect 2300 CFU/mL of S. aureus and 11 000 CFU/mL of E. coli. Clinically, the sensitivity, specificity, and accuracy were 65.7%, 100%, and 81.6%, respectively, for the culture method; 81.5%, 84.8%, and 83.1%, respectively, for DNA-based qPCR; and 73.6%, 100%, and 85.9%, respectively, for RNA-based qPCR. CONCLUSIONS: DNA-based qPCR could detect suspected PJI with high sensitivity after antibiotic therapy. RNA-based qPCR could reduce the false positive rates of DNA-based assays. qPCR-based methods could improve the efficiency of PJI diagnosis.

Comparison of culture and broad-range polymerase chain reaction methods for diagnosing periprosthetic joint infection: analysis of joint fluid, periprosthetic tissue, and sonicated fluid.

PURPOSE: This study compared the diagnostic capabilities of culture and broad-range polymerase chain reaction (PCR) using joint fluid (JF), periprosthetic tissue (PT), and sonicated fluid (SF) for the diagnosis of periprosthetic joint infection (PJI). METHODS: Sixty-seven subjects underwent knee or hip revision surgery, with 53 PJI and 14 aseptic failure (AF) cases included retrospectively. JF, PT, and SF samples were collected after a suspension of antibiotics more than two weeks, and culture and broad-range PCR were performed for all samples. RESULTS: The sensitivities of SF culture (83.0%), JF-PCR (83.0%), and SF-PCR (84.9%) were similar (P > 0.05), but each was significantly more sensitive than JF culture (69.8%), PT culture (71.7%), and PT-PCR (34.0%) (P < 0.05). The specificities of JF culture, PT culture, SF culture, JF-PCR, PT-PCR, and SF-PCR were similar (100, 100, 85.7, 85.7, 100, and 78.6%, respectively) (P > 0.05). PCR was unable to accurately detect six polymicrobial infections and two fungal infections. CONCLUSIONS: SF culture, JF-PCR, and SF-PCR were more sensitive than JF culture, PT culture, and PT-PCR for diagnosing PJI among patients who have stopped taking antibiotics for two weeks or more. Compared with PCR methods, SF culture has the advantage of detecting polymicrobial or fungal infections. PT-PCR proved to be insufficiently sensitive for providing correct diagnoses.

Janus second-order nonlinear optical dendrimers: their controllable molecular topology and corresponding largely enhanced performance.

A new type of Janus dendrimers, consisting of two different side dendrons with the dipole orientation of the second-order nonlinear optical (NLO) chromophore moieties partially in a non-centrosymmetric direction, was intelligently designed and synthesized in order to enhance the macroscopic NLO performance and break through the limitation of NLO efficiency in the current molecular topological structure of azo chromophore-based polymers. This kind of Janus dendritic structure was constructed by the combination of convergent and divergent methods, with the utilization of a powerful "click chemistry reaction". The obtained three dendrimers, D-13N, D-17N and D-21N, show very high NLO performance, especially the dramatically enhanced NLO coefficient of 299 pm V-1 for D-13N, which is the highest value ever reported for polymers containing a simple azo chromophore. The new dendrimers provide a clear structure-properties relationship between high NLO efficiency and the controllable molecular topology with the non-centrosymmetrical alignment of dipole orientation, thus opening up a new avenue for the further development of NLO dendrimers with high performance and more importantly providing some clues for the rational design of functional dendrimers with controllable molecular topology.

Thiophosphates Containing Ag+ and Lone-Pair Cations with Interchiral Double Helix Show Both Ionic Conductivity and Phase Transition.

Quaternary metal thiophosphates containing second-order Jahn-Teller distorted d10 Ag+ and lone-pair cations, Ag3Bi(PS4)2 (1), Ag7Sn(PS4)3 (2), and Ag7Pb(PS4)3 (3), were obtained by solid-state synthesis. The structural frameworks of 2 and 3 feature an infinite 1-D interchiral double helix ∞1(Ag3P2S11), which is rare in inorganic compounds. Compound 3 undergoes a significant first-order structural phase transition from monoclinic to hexagonal at ∼204 °C. This can be ascribed to the significant mismatch in the expansion coefficients between Pb-S (Ag-S) and P-S bonds evaluated by bond valence theory. The three compounds are Ag+ ionic conductors, and Ag+ ion migration pathways are proposed by calculating maps of low bond valence mismatch. Moreover, the optical properties of the three compounds were studied, and electronic structure calculations were performed. The combination of second-order Jahn-Teller distorted d10 cation and lone-pair cation provides a new strategy to explore new metal thiophosphates with interesting structures and promising properties.

Phase Transition and Second Harmonic Generation in Thiophosphates Ag2Cd(P2S6) and AgCd3(PS4)S2 Containing Two Second-Order Jahn-Teller Distorted Cations.

Two new phases in the Ag-Cd-P-S system containing two second-order Jahn-Teller (SOJT) distorted d10 cations (Cd2+ and Ag+), namely, Ag2Cd(P2S6) (1) and AgCd3(PS4)S2 (2), are obtained via medium-temperature solid-state synthesis. Compound 1 exhibits a two-dimensional layered structure and undergoes a first-order structural phase transition at approximately 280 °C. This outcome can be ascribed to the significant mismatch in the expansion coefficients between Cd-S (Ag-S) and P-P (P-S) bonds evaluated through bond valence theory. The three-dimensional non-centrosymmetric (NCS) framework of 2 is constructed by two types of tetrahedral layers consisting of corner-shared CdS4, AgS4, and PS4 tetrahedra. Compound 2 exhibits second harmonic generation (SHG) intensity of 0.45 times that of commercial AgGaS2 (AGS) at a laser irradiation of 1.85 µm and an optical band gap of 2.56 eV, and no intrinsic vibrational absorption of chemical bonds is observed in the range of 2.5-18.2 µm. Both phase transition in 1 and SHG properties in 2 are closely related to the SOJT distorted d10 cations and diverse phosphorus-sulfur polyanions (PaSb)n-, which together can easily result in NCS distorted structures and interesting properties.

Syntheses, Structures, and Nonlinear Optical Properties of Two Sulfides Na2In2MS6 (M = Si, Ge).

The first two new Na-containing sulfides Na2In2MS6 (M = Si (1), Ge (2)) in the Na2Q-B2Q3-CQ2 (B = Ga, In; C = Si, Ge, Sn; Q = S, Se) system were prepared for the first time through conventional high-temperature solid-state reaction. They are isostructural with space group Cc (No. 9) in monoclinic phases and feature three-dimensional frameworks built by the (∞)¹[In2MS6]²â» (M = Si, Ge) chains through corner-sharing InS4 tetrahedra and MS4 (M = Si, Ge) tetrahedra, with Na⁺ cation located in the cavities. They display moderate second harmonic generation (SHG) conversion efficiencies compared with commercial AgGaS2, with phase-matching behavior at 1800 nm and laser-induced damage thresholds 6.9 and 4.0 times higher than that of AgGaS2, respectively. Therefore, the output SHG intensities of 1 and 2 will be ∼4.3 and 4.0 times larger than that of AgGaS2, when the intensity of incident laser increased to close the damage energy of 1 and 2, indicating their potential for high-power nonlinear optical application.