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Abstract Background Insulin resistance (IR) induces hyperinsulinemia, which activates downstream signaling pathways such as the phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathway, ultimately leading to abnormal proliferation and apoptosis of endometrial cells. This is thought to be a key pathogenic mechanism underlying the development of endometrial polyps (EP). This study aims to investigate the relationship between IR and the development of EP, the expression levels of downstream signaling molecules, including PI3K and AKT, and related laboratory parameters were examined. Methods A total of 100 patients who visited the gynecology outpatient clinic of Zhongda Hospital affiliated with Southeast University from May 2021 to March 2023 and were diagnosed with abnormal endometrial echoes by vaginal ultrasound and underwent hysteroscopic diagnostic curettage were enrolled in this study. General data and relevant hematological indicators were compared, and intraoperative specimens were obtained for pathological examination. Possible factors influencing the development of endometrial polyps were analyzed using Pearson correlation analysis and logistic regression analysis. Results In terms of body mass index, waist circumference, fasting insulin, insulin resistance index, serum total testosterone, and free testosterone index, women of childbearing age in the endometrial polyp group had higher values than those in the non-polyp group, while sex hormone-binding globulin in the endometrial polyp group was lower than that in the non-polyp group, and the differences were statistically significant (P

Resistance seam welding additive manufacturing (RSAM) is a new solid-state additive manufacturing technique that utilizes pulsed current and pressure to welding powders layer by layer. In this study, Al1060 powder was employed as the raw material to prepare R0 and R10 samples through RSAM technology and subsequent repeated welding processes, respectively. The results showed that, compared to R0, the grain size of the R10 sample decreased from 34.3 μm to 8.7 μm, and the dislocation density increased from 4.355 × 1014 to 9.436 × 1014 m−2. Additionally, due to the additional heat and pressure from repeated welding, the porosity decreased from 0.998% to 0.017%, the ultimate tensile strength and elongation improved from 63.5 ± 0.5 MPa and 4.5 ± 0.1% in R0 to 93.3 ± 0.5 MPa and 34.3 ± 0.1% in R10. The improvement in mechanical properties is primarily due to the combined effects of grain refinement, dislocation strengthening, and pore self-healing. This study introduces a feasible new approach for additive manufacturing of aluminum alloys and other materials that is difficult to be additively manufactured by other methods.

Atherosclerosis is featured as chronic low-grade inflammation in the arteries, which leads to the formation of plaques rich in lipids. M2 macrophage-derived extracellular vesicles (M2EV) have significant potential for anti-atherosclerotic therapy. However, their therapeutic effectiveness has been hindered by their limited targeting capability in vivo. The objective of this study was to create the P-M2EV (platelet membrane-modified M2EV) using the membrane fusion technique in order to imitate the interaction between platelets and macrophages. P-M2EV exhibited excellent physicochemical properties, and microRNA (miRNA)-sequencing revealed that the extrusion process had no detrimental effects on miRNAs carried by the nanocarriers. Remarkably, miR-99a-5p was identified as the miRNA with the highest expression level, which targeted the mRNA of Homeobox A1 (HOXA1) and effectively suppressed the formation of foam cells in vitro. In an atherosclerotic low-density lipoprotein receptor-deficient (Ldlr−/−) mouse model, the intravenous injection of P-M2EV showed enhanced targeting and greater infiltration into atherosclerotic plaques compared to regular extracellular vesicles. Crucially, P-M2EV successfully suppressed the progression of atherosclerosis without causing systemic toxicity. The findings demonstrated a biomimetic platelet-mimic system that holds great promise for the treatment of atherosclerosis in clinical settings.

Polymetallic contamination of soils caused by mining activities seriously threatens soil fertility, biodiversity and human health. Bioremediation is thought to be of low cost and has minimal environmental risk but its effectiveness needs to be improved. This study aimed to identify the combined effect of plant growth and microbial strains with different functions on the enhancement of bioremediation of polymetallic contaminated soil. The microbiological mechanism of bioremediation was explored by amplicon sequencing and gene prediction. Soil was collected from polymetallic mine wastelands and a non-contaminated site for use in a pot experiment. Remediation efficiency of this method was evaluated by planting ryegrass and applying a mixed bacterial consortium comprising P-solubilizing, N-fixing and SO4-reducing bacteria. The plant-microbe joint remediation method significantly enhanced the above-ground biomass of ryegrass and soil nutrient contents, and at the same time reduced the content of heavy metals in the plant shoots and soil. The application of the composite bacterial inoculum significantly affected the structure of soil bacterial communities and increased the bacterial diversity and complexity, and the stability of co-occurrence networks. The relative abundance of the multifunctional genera to which the strains belonged showed a significant positive correlation with the soil nutrient content. Genera related to carbon (C), nitrogen (N), phosphorus (P), and sulphur (S) cycling and heavy metal resistance showed an up-regulation trend in heavy metal-contaminated soils after the application of the mixed bacterial consortium. Also, bacterial strains with specific functions in the mixed consortium regulated the expression of genes involved in soil nutrient cycling, and thus assisted in making the soil self-sustainable after remediation. These results suggested that the remediation of heavy metal-contaminated soil needs to give priority to the use of multifunctional bacterial agents.

Background: Observational studies have shown that the correlation between neurodegenerative diseases and colorectal cancer (CRC) remains controversial. Therefore, this study aimed to verify the causal association between these two diseases. Methods: Mendelian randomization (MR) analysis was used to assess the causal relationships between five major neurodegenerative diseases and CRC. Multivariable MR (MVMR) analysis was conducted to assess the direct causal effect of neurodegenerative diseases on CRC. Colocalization and pathway enrichment analyses were conducted to further elucidate our results. Sensitivity analysis was conducted to assess the robustness of the results. Results: Genetically predicted Alzheimer's disease (AD) nominally increased CRC risk (OR = 1.0620, 95%CI = 1.0127–1.1136, P = 0.013). There was no causal effect of genetically predicted CRC on neurodegenerative diseases. Furthermore, we demonstrated that genetically predicted AD marginally increased colon cancer risk (OR = 1.1621, 95%CI = 1.0267–1.3153, P = 0.017). Genetically predicted Lewy body dementia (LBD) had a significant causal effect on the increasing risk of colon cancer (IVW OR = 1.1779, 95%CI = 1.0694–1.2975, P = 0.001). MVMR indicated that effect of AD on colon cancer was driven by LBD, type 2 diabetes, body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, total cholesterol (TC), processed meat consumption, smoking, alcohol consumption, and educational attainment, whereas the effect of LBD on colon cancer was only influenced by TC. Colocalization and pathway enrichment analysis suggested that LBD and colon cancer possibly shared causal variants (nearby gene APOE), and ERBB4 signaling and lipid metabolism may mediate the causal association between LBD and colon cancer. Sensitivity analysis confirmed the reliability of our findings. Conclusions: Our study demonstrated that genetic vulnerabilities to AD nominally increased the overall risk of CRC and colon cancer. Genetically predicted LBD indicated an elevated risk of colon cancer, potentially linked to ERBB4 signaling and lipid metabolism.

We propose and demonstrate a high-quality ($Q$) bound state in the continuum (BIC) cavity based on a hexagonal lattice photonic crystal (PhC) slab with $C_{6}$ symmetry, which carries high-order topological charges of $q=-\text{2}$. By combining the lateral photonic bandgap and high-order topological charge, we realize a $Q$ of $\text{7}\times \text{10}^{4}$ in the experiment which is several times higher than traditional BIC cavities with topological charge of $q=\pm\text{1}$. Specifically, we found that the boundary orientation would significantly influence the performance of lateral confinement. In contrast to an X direction boundary, a gradient J direction boundary can best alleviate the shortcoming of lateral leakage due to incomplete bandgap and the scattering because of momentum mismatching, and relax the strict constraints on wafer thickness. Our findings could broaden the application of BIC cavities from bio-sensing to on-chip telecommunication.

Abstract Several observational studies have revealed an association between autoimmune diseases (AIDs) and colorectal cancer (CRC), although their causal association remained controversial. Therefore, our study used a two-sample Mendelian randomization (MR) analysis to verify the causal association between AIDs and CRC. We employed three common MR approaches, including inverse variance weighted (IVW), weighted median, and MR-Egger methods, to assess the causal association between type 1 diabetes (T1D), systemic lupus erythematosus, rheumatoid arthritis, psoriasis, multiple sclerosis, juvenile idiopathic arthritis, celiac disease, and primary sclerosing cholangitis (PSC) and CRC. The reverse MR analysis was performed to assess the possibility of reverse causation. To evaluate the validity of the analysis, we also performed sensitivity analysis, such as the heterogeneity test, the horizontal pleiotropy test, and the leave-one-out sensitivity analysis, and validated the results in the validation cohort. Our results showed that genetically predicted T1D was nominally associated with a lower risk of CRC (IVW OR = 0.965, 95% CI = 0.939–0.992, P = 0.012). However, genetic susceptibility to psoriasis nominally increased the risk of CRC (IVW OR = 1.026, 95% CI = 1.002–1.050, P = 0.037). Genetically predicted PSC had a significant causal effect on the increasing risk of CRC (IVW OR = 1.038, 95% CI = 1.016–1.060, P = 5.85 × 10−4). Furthermore, the MR analysis between PSC and the CRC validation cohort indicated consistent results. We found no causal association between genetically predicted other five AIDs and CRC (P > 0.05). The results of reverse MR analysis showed that genetically predicted CRC had no causal effect on T1D, psoriasis, and PSC (P > 0.05). The sensitivity analysis demonstrated that the results of the MR analysis were reliable. Our findings help to understand the causal association between AIDs and CRC, which deserves further investigation.

BackgroundSchizophrenia (SCZ) is a severe neurodevelopmental disorder with brain dysfunction. This study aimed to use bioinformatic analysis to identify candidate blood biomarkers for SCZ.MethodsThe study collected peripheral blood leukocyte samples of 9 SCZ patients and 20 healthy controls for RNA sequencing analysis. Bioinformatic analyses included differentially expressed genes (DEGs) analysis, pathway enrichment analysis, and weighted gene co-expression network analysis (WGCNA).ResultsThis study identified 1,205 statistically significant DEGs, of which 623 genes were upregulated and 582 genes were downregulated. Functional enrichment analysis showed that DEGs were mainly enriched in cell chemotaxis, cell surface, and serine peptidase activity, as well as involved in Natural killer cell-mediated cytotoxicity. WGCNA identified 16 gene co-expression modules, and five modules were significantly correlated with SCZ (p < 0.05). There were 106 upregulated genes and 90 downregulated genes in the five modules. The top ten genes sorted by the Degree algorithm were RPS28, BRD4, FUS, PABPC1, PCBP1, PCBP2, RPL27A, RPS21, RAG1, and RPL27. RAG1 and the other nine genes belonged to the turquoise and pink module respectively. Pathway enrichment analysis indicated that these 10 genes were mainly involved in processes such as Ribosome, cytoplasmic translation, RNA binding, and protein binding.ConclusionThis study finds that the gene functions in key modules and related enrichment pathways may help to elucidate the molecular pathogenesis of SCZ, and the potential of key genes to become blood biomarkers for SCZ warrants further validation.

Mg3Sb2 has been considered a highly promising thermoelectric material for mid-temperature applications. Optimizing the properties of the material is crucial for accelerating its commercial use. In this work, first-principles molecular simulations of P-type Mg3Sb2 doped with the carbon group elements Ge and Si have been carried out. Results indicate that doping with Ge and Si enhances the thermodynamic stability and electrical conductivity of the material. This improvement is achieved by decreasing the bandgap, increasing the local and peak density of states, flattening the band structure, and elevating the relative mass of carriers. Additionally, doping with Ge and Si decreases the phonon velocity and Debye temperature, which weakens the thermal transport properties of the material. These findings suggest that Ge and Si doping is an effective method for improving the thermoelectric properties of the material. At the same doping concentration, the Si single-doped system possesses the smallest bandgap value with the highest peak density of states and forms an indirect bandgap, leading to the best electrical transport properties; the Ge single-doped system has the lowest phonon velocity and Debye temperature, which has the most significant effect in attenuating the thermal transport properties of the material; and the Ge–Si co-doped system has the highest relative mass of carriers, which is conducive to the enhancement of Seebeck coefficient. The results offer theoretical guidance for experimentally analyzing the effects of Ge and Si doping on the thermoelectric properties of Mg3Sb2.

Studies have shown that the prostaglandin (PG) family acts as allergic inflammatory mediator in malignant diseases. Furthermore, prostaglandin E2 (PGE2) and its related receptors, as well as the prostaglandin D2 (PGD2)/PGD2 receptor (PTGDR2), play irreplaceable roles in tumorigenesis and anti-tumor therapy. Several experiments have demonstrated that PGD2 signaling through PTGDR2 not only directly inhibits cancer cell survival, proliferation, and migration but also reduces resistance towards conventional chemotherapeutic agents. Recent studies from our and other laboratories have shown that PGD2, its ligands, and related metabolites can significantly alter the tumor microenvironment (TME) by promoting the secretion of chemokines and cytokines, thereby inhibiting tumor progression. Additionally, reduced PGD2 expression has been associated with poor prognosis in patients with gastric, breast, lung, and pancreatic cancers, validating the preclinical findings and their clinical relevance. This review focuses on the current understanding of PGD2/PTGDR2 expression patterns and biological activity in cancer, proposing questions to guide the assessment of PGD2 and its receptors as potential targets for effective cancer therapies.

Sepsis-induced myocardial dysfunction (SIMD) is associated with poor prognosis and increased mortality in patients with sepsis. Cytokines are important regulators of both the initiation and progression of sepsis. Interleukin-15 (IL-15), a pro-inflammatory cytokine, has been linked to protective effects against myocardial infarction and myocarditis. However, the role of IL-15 in SIMD remains unclear. We established a mouse model of SIMD via cecal ligation puncture (CLP) surgery and a cell model of myocardial injury via lipopolysaccharide (LPS) stimulation. IL-15 expression was prominently upregulated in septic hearts as well as cardiomyocytes challenged with LPS. IL-15 pretreatment attenuated cardiac inflammation and cell apoptosis and improved cardiac function in the CLP model. Similar cardioprotective effects of IL-15 pretreatment were observed in vitro. As expected, IL-15 knockdown had the opposite effect on LPS-stimulated cardiomyocytes. Mechanistically, we found that IL-15 pretreatment reduced the expression of the pro-apoptotic proteins cleaved caspase-3 and Bax and upregulated the anti-apoptotic protein Bcl-2. RNA sequencing and Western blotting further confirmed that IL-15 pretreatment suppressed the activation of nuclear factor kappa B (NF-κB) signaling in mice with sepsis. Besides, the addition of NF-κB inhibitor can significantly attenuate cardiomyocyte apoptosis compared to the control findings. Our results suggest that IL-15 pretreatment attenuated the cardiac inflammatory responses and reduced cardiomyocyte apoptosis by partially inhibiting NF-κB signaling in vivo and in vitro, thereby improving cardiac function in mice with sepsis. These findings highlight a promising therapeutic strategy for SIMD.

Sensing the lowering of endoplasmic reticulum (ER) calcium (Ca2+), STIM1 mediates a ubiquitous Ca2+ influx process called the store-operated Ca2+ entry (SOCE). Dysregulated STIM1 function or abnormal SOCE is strongly associated with autoimmune disorders, atherosclerosis, and various forms of cancers. Therefore, uncovering the molecular intricacies of post-translational modifications, such as oxidation, on STIM1 function is of paramount importance. In a recent proteomic screening, we identified three protein disulfide isomerases (PDIs)—Prolyl 4-hydroxylase subunit beta (P4HB), protein disulfide-isomerase A3 (PDIA3), and thioredoxin domain-containing protein 5 (TXNDC5)—as the ER-luminal interactors of STIM1. Here, we demonstrated that these PDIs dynamically associate with STIM1 and STIM2. The mutation of the two conserved cysteine residues of STIM1 (STIM1-2CA) decreased its Ca2+ affinity both in cellulo and in situ. Knockdown of PDIA3 or P4HB increased the Ca2+ affinity of wild-type STIM1 while showing no impact on the STIM1-2CA mutant, indicating that PDIA3 and P4HB regulate STIM1’s Ca2+ affinity by acting on ER-luminal cysteine residues. This modulation of STIM1’s Ca2+ sensitivity was further confirmed by Ca2+ imaging experiments, which showed that knockdown of these two PDIs does not affect STIM1-mediated SOCE upon full store depletion but leads to enhanced SOCE amplitudes upon partial store depletion. Thus, P4HB and PDIA3 dynamically modulate STIM1 activation by fine-tuning its Ca2+ binding affinity, adjusting the level of activated STIM1 in response to physiological cues. The coordination between STIM1-mediated Ca2+ signaling and redox responses reported herein may have implications for cell physiology and pathology.

Researching the structural characteristics of the spatial correlation network of cultivated land utilization ecological efficiency is of great significance to China's food security and agricultural green and low-carbon development. Taking 47 cities (autonomous prefectures) in the upper reaches of the Yangtze River as the research object, the ecological efficiency of cultivated land utilization from 2010 to 2020 was measured based on the unexpected output model (Super SBM), and the spatial correlation matrix was constructed using the revised gravity model. The structural characteristics of the spatial correlation network were analyzed using the social network model (SNA), and finally, the factors affecting the spatial correlation network of cultivated land utilization ecological efficiency in the upper reaches of the Yangtze River were analyzed through the quadratic assignment procedure (QAP) model. The results show that: (1) the ecological efficiency of cultivated land utilization in the upper reaches of the Yangtze River has been increasing year by year, but the overall level is low, and there is a large gap among provinces. Sichuan Province has the highest average value of 0.605, and Yunnan Province has the lowest average value of 0.359. (2) The ecological efficiency of cultivated land utilization in the upper reaches of the Yangtze River has broken through the provincial boundaries and has formed an obvious spatial correlation network, but the overall density is low, and the network is still relatively loose, needing further development and improvement. Chengdu, Yibin, Luzhou, and other cities are located in the center of the network and have formed four cohesive subgroups. (3)The differences in the level of agricultural economic development, the rural per capita disposable income, the differences in agricultural mechanization intensity, the regional population differences, and spatial adjacency have an impact on the spatial network of ecological efficiency of cultivated land utilization in the upper reaches of the Yangtze River. The difference in the level of agricultural economic development, the rural per capita disposable income, and the differences in agricultural mechanization intensity are negatively correlated, while the regional population differences are positively correlated with spatial adjacency.

This investigation employed different laser powers to conduct the laser welding–brazing process of 5052 aluminum alloy to both Al-Si coated and uncoated 22MnB5 steel. The flux-cored Zn-Al22 filler metal was employed during the procedure. The influence of Al-Si coatings on the microstructure and corrosion resistance of Al/Steel welded joints was investigated using microstructural characterization and electrochemical tests. It was noted that the interfacial microstructure of the laser Al/steel joints was significantly altered by the Al-Si coating. Moreover, the Al-Si coating suppressed the formation and growth of the interfacial reaction layer. Electrochemical corrosion tests showed that the impact of Al-Si coating on the corrosion resistance of laser joints depended on the laser powers and thickness of the interfacial intermetallic compound (IMC) layer. The research suggests that galvanic corrosion occurs due to the differences in corrosion potential between fusion zone (FZ), steel, and Fe-Al-Zn IMCs, which accelerate the corrosion of the joint. The IMC layer acts as a cathode to accelerate the corrosion of the FZ and as an anode to protect the steel from corrosion.

Hainan yellow cattle are indigenous Zebu cattle from southern China known for their tolerance of heat and strong resistance to disease. Generations of adaptation to the tropical environment of southern China and decades of artificial breeding have left identifiable selection signals in their genomic makeup. However, information on the selection signatures of Hainan yellow cattle is scarce. Herein, we compared the genomes of Hainan yellow cattle with those of Zebu, Qinchuan, Nanyang, and Yanbian cattle breeds by the composite likelihood ratio method (CLR), Tajima’s D method, and identifying runs of homozygosity (ROHs), each of which may provide evidence of the genes responsible for heat tolerance in Hainan yellow cattle. The results showed that 5210, 1972, and 1290 single nucleotide polymorphisms (SNPs) were screened by the CLR method, Tajima’s D method, and ROH method, respectively. A total of 453, 450, and 325 genes, respectively, were identified near these SNPs. These genes were significantly enriched in 65 Gene Ontology (GO) functional terms and 11 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways (corrected p < 0.05). Five genes—Adenosylhomocysteinase-like 2, DnaJ heat shock protein family (Hsp40) member C3, heat shock protein family A (Hsp70) member 1A, CD53 molecule, and zinc finger and BTB domain containing 12—were recognized as candidate genes associated with heat tolerance. After further functional verification of these genes, the research results may benefit the understanding of the genetic mechanism of the heat tolerance in Hainan yellow cattle, which lay the foundation for subsequent studies on heat stress in this breed.

Tunchang pigs are an indigenous pig population in China known for their high tolerance to roughage, delicious meat, and fecundity. However, the number of Tunchang pigs has been declining due to the influence of commercial breeds and African swine fever, which could potentially lead to inbreeding. To assess the inbreeding level and the genetic basis of important traits in Tunchang pigs, our research investigated the patterns in “runs of homozygosity” (ROHs) using whole genome resequencing data from 32 Tunchang pigs. The study aimed to determine the length, number, coverage, and distribution model of ROHs in Tunchang pigs, as well as genomic regions with high ROH frequencies. The results of the study revealed that a total of 20,499,374 single-nucleotide polymorphisms (SNPs) and 1953 ROH fragments were recognized in 32 individuals. The ROH fragments in Tunchang pigs were predominantly short, ranging from 0.5 to 1 megabases (Mb) in length. Furthermore, the coverage of ROHs varied across chromosomes, with chromosome 3 having the highest coverage and chromosome 11 having the lowest coverage. The genetic diversity of Tunchang pigs was found to be relatively high based on the values of HE (expected heterozygosity), HO (observed heterozygosity), pi (nucleotide diversity), Ne (effective population size), and MAF (minor allele frequency). The average inbreeding coefficients of Tunchang pigs, as determined by three different methods (FHOM, FGRM, and FROH), were 0.019, 0.0138, and 0.0304, respectively. These values indicate that the level of inbreeding in Tunchang pigs is currently low. Additionally, the study identified a total of 13 ROH islands on all chromosomes, which in total contained 38,913 SNPs and 120 genes. These ROH islands included genes associated with economically important traits, including meat quality (GYS1, PHLPP1, SLC27A5, and CRTC1), growth and development (ANKS1A, TAF11, SPDEF, LHB, and PACSIN1), and environmental adaptation (SLC26A7). The findings of this research offer valuable perspectives on the present status of Tunchang pig resources and offer a reference for breeding conservation plans and the efficient utilization of Tunchang pigs in the future. By understanding the inbreeding level and genetic basis of important traits in Tunchang pigs, conservation efforts can be targeted towards maintaining genetic diversity and promoting the sustainable development of this indigenous pig population.

Purpose: This study set out to investigate whether individuals with dysphonia, as determined by either self-assessment or clinician-based auditory-perceptual judgment, exhibited differences in perilaryngeal muscle activities using surface electromyography (sEMG) during various phonatory tasks. Additionally, the study aimed to assess the effectiveness of sEMG in identifying dysphonic cases. Method: A total of 77 adults (44 women, 33 men, Mage = 30.4 years) participated in this study, with dysphonic cases identified separately using either a 10-item Voice Handicap Index (VHI-10) or clinician-based auditory-perceptual voice quality (APVQ) evaluation. sEMG activities were measured from the areas of suprahyoid and sternocleidomastoid muscles during prolonged vowel /i/ phonations at different pitch and loudness levels. Normalized root-mean-square value against the maximal voluntary contraction (RMS %MVC) of the sEMG signals was obtained for each phonation and compared between subject groups and across phonatory tasks. Additionally, binary logistic regression analysis was performed to determine how the sEMG measures could predict the VHI-10-based or APVQ-based dysphonic cases. Results: Participants who scored above the criteria on either the VHI-10 (n = 29) or APVQ judgment (n = 17) exhibited significantly higher RMS %MVC in the right suprahyoid muscles compared to the corresponding control groups. Although the RMS %MVC value from the right suprahyoid muscles alone was not a significant predictor of self-evaluated dysphonic cases, a combination of the RMS %MVC values from both the right and left suprahyoid muscles significantly predicted APVQ-based dysphonic cases with a 69.66% fair level. Conclusions: This study found that individuals with dysphonia, as determined by either self-assessment or APVQ judgment, displayed more imbalanced suprahyoid muscle activities in voice production compared to nondysphonic groups. The combination of the sEMG measures from both left and right suprahyoid muscles showed potential as a predictor of dysphonia with a fair level of confidence. Supplemental Material: https://doi.org/10.23641/asha.25112804 [ABSTRACT FROM AUTHOR]

Grating couplers that interconnect photonic chips to off-chip components are crucial for various optoelectronics applications. Despite numerous efforts in past decades, the existing grating couplers are still far from optimal in energy efficiency and thus hinder photonic integration toward a larger scale. Here, we propose a strategy to achieve ultralow-loss grating couplers by using unidirectional guided resonances (UGRs), suppressing the useless downward radiation with no mirror on the bottom. By engineering the dispersion and apodizing the geometry of grating, we experimentally realize a grating coupler with a record-low loss of -0.34 dB and 1-dB bandwidth exceeding 30 nm at the telecom wavelength of 1550 nm and further demonstrate an optic via with a loss of only -0.94 dB. Given that UGRs ubiquitously exist in a variety of grating geometries, our work sheds light on a systematic method to achieve energy-efficient optical interconnect and paves the way to large-scale photonic integration. [ABSTRACT FROM AUTHOR]