Cell size, density, and nutrient dependency of unicellular algal gravitational sinking velocities.

Eukaryotic phytoplankton, also known as algae, form the basis of marine food webs and drive marine carbon sequestration. Algae must regulate their motility and gravitational sinking to balance access to light at the surface and nutrients in deeper layers. However, the regulation of gravitational sinking remains largely unknown, especially in motile species. Here, we quantify gravitational sinking velocities according to Stokes' law in diverse clades of unicellular marine microalgae to reveal the cell size, density, and nutrient dependency of sinking velocities. We identify a motile algal species, Tetraselmis sp., that sinks faster when starved due to a photosynthesis-driven accumulation of carbohydrates and a loss of intracellular water, both of which increase cell density. Moreover, the regulation of cell sinking velocities is connected to proliferation and can respond to multiple nutrients. Overall, our work elucidates how cell size and density respond to environmental conditions to drive the vertical migration of motile algae.

Genomic prediction of regional-scale performance in switchgrass (Panicum virgatum) by accounting for genotype-by-environment variation and yield surrogate traits.

Switchgrass is a potential crop for bioenergy or carbon capture schemes, but further yield improvements through selective breeding are needed to encourage commercialization. To identify promising switchgrass germplasm for future breeding efforts, we conducted multi-site and multi-trait genomic prediction with a diversity panel of 630 genotypes from 4 switchgrass subpopulations (Gulf, Midwest, Coastal, and Texas), which were measured for spaced plant biomass yield across 10 sites. Our study focused on the use of genomic prediction to share information among traits and environments. Specifically, we evaluated the predictive ability of cross-validation (CV) schemes using only genetic data and the training set, (cross validation 1: CV1), a subset of the sites (cross validation 2: CV2), and/or with two yield surrogates (flowering time and fall plant height). We found that genotype-by-environment interactions were largely due to the north-south distribution of sites. The genetic correlations between yield surrogates and biomass yield were generally positive (mean height r=0.85; mean flowering time r=0.45) and did not vary due to subpopulation or growing region (North, Middle, South). Genomic prediction models had cross-validation predictive abilities of -0.02 for individuals using only genetic data (CV1) but 0.55, 0.69, 0.76, 0.81, and 0.84 for individuals with biomass performance data from one, two, three, four and five sites included in the training data (CV2), respectively. To simulate a resource-limited breeding program, we determined the predictive ability of models provided with: one site observation of flowering time (0.39), one site observation of flowering time and fall height (0.51), one site observation of fall height (0.52), one site observation of biomass (0.55), and five site observations of biomass yield (0.84). The ability to share information at a regional scale is very encouraging but further research is required to accurately translate spaced plant biomass to commercial-scale sward biomass performance.

Characteristics, Treatment, and Prognosis of Pediatric Symphyseal/Parasymphyseal-Condylar Fractures.

BACKGROUND: Pediatric condylar fractures combined with symphyseal or parasymphyseal fractures are common but challenging to manage. The authors present fracture characteristics, propose a treatment algorithm, and evaluate the treatment prognosis of pediatric symphyseal/parasymphyseal-condylar fractures. METHODS: A retrospective review was conducted on pediatric patients who underwent treatment for symphyseal/parasymphyseal-condylar fractures in a trauma center between January of 2006 and January of 2021. Demographic and fracture characteristics were recorded. Complications and functional evaluations, including maximum interincisal opening, Helkimo anamnestic index, and clinical dysfunction index, were assessed after at least 1 year of follow-up. RESULTS: After screening, 104 participants met the inclusion criteria. Among them, 50.96% received open reduction and internal fixation for symphyseal/parasymphyseal fractures and closed treatment for condylar fractures, 45.19% were treated by liquid diet and functional exercise, and the remaining 3.85% with severe malocclusion were treated with the assistance of orthodontic appliances. During follow-up, the average maximum interincisal opening of the patients increased from 17 ± 6.29 mm to 41.64 ± 6.33 mm. No subjective symptoms were observed in 86.54% of the patients and 79.81% showed no or mild clinical symptoms. Except for 1 patient who developed temporomandibular joint ankylosis, no other severe complication was reported. Postfracture remodeling of the nonfractured condyle was noted in 3 cases. CONCLUSIONS: Pediatric symphyseal/parasymphyseal-condylar fractures present unique biomechanical and anatomic challenges that require special consideration during management. In this study, satisfactory functional prognosis was achieved following implementation of the treatment algorithm. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Ecological risk assessment of commonly used antibiotics in aquatic ecosystems along the coast of China.

The consistent input of antibiotics into aquatic environments may pose risks to various creatures and ecosystems. However, risk assessment of pharmaceuticals and personal care products (PPCPs) in aquatic environments is frequently limited by the lack of toxicity data. To investigate the risk of commonly used antibiotics to various aquatic creatures, we focused on the distribution patterns and temporal dynamics of antibiotics in the coastal estuary area of China and performed a comprehensive ecological risk assessment for four antibiotics: erythromycin (ERY), tetracycline (TCN), norfloxacin (NOR) and sulfamethoxazole (SMX). An interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) combined model was applied to predict the toxicity data of untested aquatic species, and an accurate ecological risk assessment procedure was developed to evaluate the risk level of PPCPs. The results of risk quotient assessments and probabilistic risk assessments (PRAs) suggested that four objective antibiotics in the Chinese coastal estuary area were at a low risk level. These antibiotics posed a high risk in antibiotic-related global hot spots, with probabilistic risk values for ERY, NOR, SMX, and TCN of 81.33 %, 27.08 %, 21.13 %, and 15.44 %, respectively. We applied an extrapolation method to overcome the lack of toxicity data in ecological risk assessment, enhanced the ecological reality of water quality criteria derivation and reduced the uncertainty of risk assessment for antibiotics.

Characterization of a new greenbug resistance gene Gb9 in a synthetic hexaploid wheat.

Greenbug [Schizaphis graminum (Rondani)] is a serious insect pest that not only damages cereal crops, but also transmits several destructive viruses. The emergence of new greenbug biotypes in the field makes it urgent to identify novel greenbug resistance genes in wheat. CWI 76364 (PI 703397), a synthetic hexaploid wheat (SHW) line, exhibits greenbug resistance. Evaluation of an F2:3 population from cross OK 14319 × CWI 76364 indicated that a dominant gene, designated Gb9, conditions greenbug resistance in CWI 76364. Selective genotyping of a subset of F2 plants with contrasting phenotypes by genotyping-by-sequencing identified 25 SNPs closely linked to Gb9 on chromosome arm 7DL. Ten of these SNPs were converted to Kompetitive allele-specific polymerase chain reaction (KASP) markers for genotyping the entire F2 population. Genetic analysis delimited Gb9 to a 0.6-Mb interval flanked by KASP markers located at 599,835,668 bp (Stars-KASP872) and 600,471,081 bp (Stars-KASP881) on 7DL. Gb9 was 0.5 cM distal to Stars-KASP872 and 0.5 cM proximal to Stars-KASP881. Allelism tests indicated that Gb9 is a new greenbug resistance gene which confers resistance to greenbug biotypes C, E, H, I, and TX1. TX1 is one of the most widely virulent biotypes and has overcome most known wheat greenbug resistance genes. The introgression of Gb9 into locally adapted wheat cultivars is of economic importance, and the KASP markers developed in this study can be used to tag Gb9 in cultivar development.

Electrochemical Reductive Cross-Coupling of Alkyl or Alkenyl Halides with gem-Difluoroalkenes.

Herein, we describe an electroreductive cross-electrophile coupling protocol for the construction of valuable monofluoroalkenes from easily accessible alkyl or alkenyl halides with gem-difluoroalkenes. The reaction can be conducted under sustainable and mild conditions delivering valuable and functionalized monofluoroalkenes with excellent Z-selectivity. The protocol's most notable advantage is the in situ release of nickel catalyst from the inexpensive electrodes without the addition of extra hazardous metal catalyst and superstoichiometric reductant.

Early prediction of gestational diabetes mellitus using maternal demographic and clinical risk factors.

OBJECTIVE: To build and validate an early risk prediction model for gestational diabetes mellitus (GDM) based on first-trimester electronic medical records including maternal demographic and clinical risk factors. METHODS: To develop and validate a GDM prediction model, two datasets were used in this retrospective study. One included data of 14,015 pregnant women from Máxima Medical Center (MMC) in the Netherlands. The other was from an open-source database nuMoM2b including data of 10,038 nulliparous pregnant women, collected in the USA. Widely used maternal demographic and clinical risk factors were considered for modeling. A GDM prediction model based on elastic net logistic regression was trained from a subset of the MMC data. Internal validation was performed on the remaining MMC data to evaluate the model performance. For external validation, the prediction model was tested on an external test set from the nuMoM2b dataset. RESULTS: An area under the receiver-operating-characteristic curve (AUC) of 0.81 was achieved for early prediction of GDM on the MMC test data, comparable to the performance reported in previous studies. While the performance markedly decreased to an AUC of 0.69 when testing the MMC-based model on the external nuMoM2b test data, close to the performance trained and tested on the nuMoM2b dataset only (AUC = 0.70).

Whole-genome sequencing of allotetraploid bermudagrass reveals the origin of Cynodon and candidate genes for salt tolerance.

Bermudagrass (Cynodon dactylon) is a globally distributed, extensively used warm-season turf and forage grass with high tolerance to salinity and drought stress in alkaline environments. However, the origin of the species and genetic mechanisms for salinity tolerance in the species are basically unknown. Accordingly, we set out to study evolution divergence events in the Cynodon genome and to identify genes for salinity tolerance. We developed a 604.0 Mb chromosome-level polyploid genome sequence for bermudagrass 'A12359' (n = 18). The C. dactylon genome comprises 2 complete sets of homoeologous chromosomes, each with approximately 30 000 genes, and most genes are conserved as syntenic pairs. Phylogenetic study showed that the initial Cynodon species diverged from Oropetium thomaeum approximately 19.7-25.4 million years ago (Mya), the A and B subgenomes of C. dactylon diverged approximately 6.3-9.1 Mya, and the bermudagrass polyploidization event occurred 1.5 Mya on the African continent. Moreover, we identified 82 candidate genes associated with seven agronomic traits using a genome-wide association study, and three single-nucleotide polymorphisms were strongly associated with three salt resistance genes: RAP2-2, CNG channels, and F14D7.1. These genes may be associated with enhanced bermudagrass salt tolerance. These bermudagrass genomic resources, when integrated, may provide fundamental insights into evolution of diploid and tetraploid genomes and enhance the efficacy of comparative genomics in studying salt tolerance in Cynodon.

Electrochemical Reductive Cross-Coupling of Vinyl Bromides for the Synthesis of 1,3-Dienes.

An electroreductive cross-electrophile coupling protocol was developed for the construction of valuable 1,3-dienes from vinyl bromides. Furthermore, this scalable method can also be used to forge complex [4 + 2] cycloadducts in a one-pot manner. One of the most important advantages of this green and sustainable protocol is the in situ release of nickel catalyst from the inexpensive electrodes without the addition of extra harmful metal catalysts and reductant.

Simulating behavior of perfluorooctane sulfonate (PFOS) in the mainstream of a river system with sluice regulations.

Perfluorooctane sulfonate (PFOS) is a persistent, anionic and ubiquitous contaminant that undergoes long-range transport within the environment. Its behavior has attracted wide-range academic and regulatory attention. In this article, a mass balance model was employed to simulate PFOS concentrations in the mainstream of Haihe River water system, encompassing sluices and artificial rivers. The dynamic simulation of PFOS concentrations in both sediment and freshwater took into account fluctuations in PFOS emissions, water levels and water discharge. Furthermore, the study delved into exploring the impacts of sluices and artificial rivers on the behavior of PFOS. The simulated concentrations of PFOS in steady state agreed with the measured concentrations in surveys carried out in Nov. 2019, July 2020, Oct. 2020, and June 2021. Every year, approximately 24 kg PFOS was discharged into the Bohai Sea with Chaobai New River being the largest contributor for 44 %. Moreover, the transport of PFOS in the original rivers is likely to be restricted by sluices and replaced by artificial rivers. Monte Carlo analysis showed that model predictions of PFOS concentrations in sediment were subject to greater uncertainty than those in freshwater as the former is impacted by more parameters, such as density of sediment. This study provides a scientific basis for the local government to manage and control PFOS.

Characterization of Quantitative Trait Loci for Leaf Rust Resistance in the Uzbekistani Wheat Landrace Teremai Bugdai.

Leaf rust, caused by Puccinia triticina, is a major cause of wheat yield losses globally, and novel leaf rust resistance genes are needed to enhance wheat leaf rust resistance. Teremai Bugdai is a landrace from Uzebekistan that is highly resistant to many races of P. triticina in the United States. To unravel leaf rust resistance loci in Teremai Bugdai, a recombinant inbred line (RIL) population of Teremai Bugdai × TAM 110 was evaluated for response to P. triticina race Pt54-1 (TNBGJ) and genotyped using single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS). Quantitative trait loci (QTL) analysis using 5,130 high-quality GBS-SNPs revealed three QTLs, QLr-Stars-2DS, QLr-Stars-6BL, and QLr.Stars-7BL, for leaf rust resistance in two experiments. QLr-Stars-2DS, which is either a new Lr2 allele or a new resistance locus, was delimited to an ∼19.47-Mb interval between 46.4 and 65.9 Mb on 2DS and explained 31.3 and 33.2% of the phenotypic variance in the two experiments. QLr-Stars-6BL was mapped in an ∼84.0-kb interval between 719.48 and 719.56 Mb on 6BL, accounting for 33 to 36.8% of the phenotypic variance in two experiments. QLr.Stars-7BL was placed in a 350-kb interval between 762.41 and 762.76 Mb on 7BL and explained 4.4 to 5.3% of the phenotypic variance. Nine GBS-SNPs flanking these QTLs were converted to kompetitive allele specific PCR (KASP) markers, and these markers can be used to facilitate their introgression into locally adapted wheat lines.

Cost-Effectiveness Analysis of Adjuvant Endocrine Therapy With Ovarian Suppression in Premenopausal Patients With Hormone Receptor-Positive Early Breast Cancer in China.

PURPOSE: Endocrine therapy combined with ovarian function suppression (OFS) is recommended in intermediate- or high-risk patients among premenopausal women with hormone receptor-positive early breast cancer. However, in China, the cost-effectiveness of this strategy compared with endocrine therapy alone is unclear. This study aimed to evaluate the long-term cost-effectiveness of tamoxifen (TAM), TAM+OFS, and exemestane plus OFS (EXE+OFS). METHODS: On the basis of prognostic data from the Suppression of Ovarian Function Trial (SOFT), cost data from the Hospital Information System of the West China Hospital of Sichuan University, and health utility values from the published literature, a Markov model was established. The incremental cost-effectiveness ratio (ICER) was used to compare the treatment strategies. RESULTS: In a 25-year simulation of adjuvant therapy in Chinese women with early breast cancer, the total costs of TAM, TAM+OFS, and EXE+OFS were $7821, $9318, and $9445, respectively. The quality-adjusted life-years (QALYs) were 11.615, 11.896, and 11.734 years, respectively. Compared with TAM, the ICERs of TAM+OFS and EXE+OFS were $5,327.4021/QALY and $13,647.0588/QALY, respectively. The ICERs of TAM+OFS and EXE+OFS were below the threshold of $32,517/QALY. The reliability and stability of the simulation results were verified using Monte Carlo simulation and sensitivity analysis. CONCLUSION: In the context of limited resources in China, TAM+OFS and EXE+OFS are cost-effective options compared with TAM.

Legacy and alternative per-and polyfluoroalkyl substances (PFASs) in the Bohai Bay Rim: Occurrence, partitioning behavior, risk assessment, and emission scenario analysis.

The use of alternative per- and polyfluoroalkyl substances (PFASs) has been practiced because of the restrictions on legacy PFASs. However, knowledge gaps exist on the ecological risks of alternatives and relationships between restrictions and emissions. This study systematically analyzed the occurrence characteristics, water-sediment partitioning behaviors, ecological risks, and emissions of legacy and alternative PFASs in the Bohai Bay Rim (BBR). The mean concentration of total PFASs was 46.105 ng/L in surface water and 6.125 ng/g dry weight (dw) in sediments. As an alternative for perfluorooctanoic acid (PFOA), hexafluoropropylene oxide dimer acid (GenX) had a concentration second only to PFOA in surface water. In sediments, perfluorobutyric acid (PFBA) and GenX were the two predominant contaminants. In the water-sediment partitioning system, GenX, 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (F-53B), and 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (8:2 Cl-PFESA) tended to be enriched towards sediments. The species sensitivity distribution (SSD) models revealed the low ecological risks of PFASs and their alternatives in the BBR. Moreover, predicted no-effected concentrations (PNECs) indicated that short-chain alternatives like PFBA and perfluorobutane sulfonate (PFBS) were safer for aquatic ecosystems, while caution should be exercised when using GenX and F-53B. Due to the incremental replacement of PFOA by GenX, cumulative emissions of 1317.96 kg PFOA and 667.22 kg GenX were estimated during 2004-2022, in which PFOA emissions were reduced by 59.2 % due to restrictions implemented since 2016. If more stringent restrictions are implemented from 2023 to 2030, PFOA emissions will further decrease by 85.0 %, but GenX emissions will increase by an additional 21.3 %. Simultaneously, GenX concentrations in surface water are forecasted to surge by 2.02 to 2.45 times in 2023. This study deepens the understanding of PFAS alternatives and assists authorities in developing policies to administer PFAS alternatives.

Single-cell mass distributions reveal simple rules for achieving steady-state growth.

IMPORTANCE: Microbiologists have watched clear liquid turn cloudy for over 100 years. While the cloudiness of a culture is proportional to its total biomass, growth rates from optical density measurements are challenging to interpret when cells change size. Many bacteria adjust their size at different steady-state growth rates, but also when shifting between starvation and growth. Optical density cannot disentangle how mass is distributed among cells. Here, we use single-cell mass measurements to demonstrate that a population of cells in batch culture achieves a stable mass distribution for only a short period of time. Achieving steady-state growth in rich medium requires low initial biomass concentrations and enough time for individual cell mass accumulation and cell number increase via cell division to balance out. Steady-state growth is important for reliable cell mass distributions and experimental reproducibility. We discuss how mass variation outside of steady-state can impact physiology, ecology, and evolution experiments.

Genetic diversity and population structure of bermudagrass (Cynodon spp.) revealed by genotyping-by-sequencing.

Bermudagrass (Cynodon spp.) breeding and cultivar development is hampered by limited information regarding its genetic and phenotypic diversity. To explore diversity in bermudagrass, a total of 206 Cynodon accessions consisting of 193 common bermudagrass (C. dactylon var. dactylon) and 13 African bermudagrass (C. transvaalensis) accessions of worldwide origin were assembled for genetic characterization. Genotyping-by-sequencing (GBS) was employed for genetic marker development. With a minor allele frequency of 0.05 and a minimum call rate of 0.5, a total of 37,496 raw single nucleotide polymorphisms (SNPs) were called de novo and were used in the genetic diversity characterization. Population structure analysis using ADMIXTURE revealed four subpopulations in this germplasm panel, which was consistent with principal component analysis (PCA) and phylogenetic analysis results. The first three principal components explained 15.6%, 10.1%, and 3.8% of the variance in the germplasm panel, respectively. The first subpopulation consisted of C. dactylon accessions from various continents; the second subpopulation was comprised mainly of C. transvaalensis accessions; the third subpopulation contained C. dactylon accessions primarily of African origin; and the fourth subpopulation represented C. dactylon accessions obtained from the Oklahoma State University bermudagrass breeding program. Genetic diversity parameters including Nei's genetic distance, inbreeding coefficient, and Fst statistic revealed substantial genetic variation in the Cynodon accessions, demonstrating the potential of this germplasm panel for further genetic studies and cultivar development in breeding programs.

Research progress of severe acute respiratory syndrome coronavirus 2 on aerosol collection and detection.

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019 has negatively affected people's lives and productivity. Because the mode of transmission of SARS-CoV-2 is of great concern, this review discusses the sources of virus aerosols and possible transmission routes. First, we discuss virus aerosol collection methods, including natural sedimentation, solid impact, liquid impact, centrifugal, cyclone and electrostatic adsorption methods. Then, we review common virus aerosol detection methods, including virus culture, metabolic detection, nucleic acid-based detection and immunology-based detection methods. Finally, possible solutions for the detection of SARS-CoV-2 aerosols are introduced. Point-of-care testing has long been a focus of attention. In the near future, the development of an instrument that integrates sampling and output results will enable the real-time, automatic monitoring of patients.

Multimedia fate of sulfamethoxazole (SMX) in a water-scarce city by coupling fugacity model and HYDRUS-1D model.

Increased concentrations of pharmaceutical and personal care products (PPCPs) have raised concerns about their impact on the ecological system and human health. To understand the environmental impact of PPCPs, we evaluated the fate of a typical PPCP of sulfamethoxazole (SMX) in a water-scarce city of Tianjin during 2013-2020 using a coupled model based on the dynamic fugacity model and HYDRUS-1D model. The results showed that the coupled model successfully simulated the reported SMX concentrations in the main fate media of water and soils, which accounted for 46.4 % and 53.0 % with equilibrium concentrations of 135-165 ng/L and 0.4-0.5 ng/g, respectively. The cross-media transfer flux results showed that advection was the prime input path for SMX in water, while degradation was the dominant output path. Wastewater irrigation and degradation were the main transfer processes of SMX in the soil. Moreover, human activities (i.e., emission loads) and climate (i.e., temperature and precipitation) change can significantly affect the concentrations and transfer rate of SMX in the media. These findings provide basic data and methods for the risk assessment of SMX in water-scarce regions.

meta-Selective O-Arylation of Cyclic Diaryliodonium Salts with Phenols via Aryne Intermediates.

Herein, we report a base-mediated, highly meta-selective O-arylation process of phenols and cyclic diaryliodonium salts without usage of transition metals. This novel and practical method was proved to be useful for the synthesis of iodine-containing meta-functionalized biaryl ethers in a broad functional group tolerance and environmentally friendly manner. Diversity-oriented transformations of the products were carried out to give various valuable functionalized biaryls. Preliminary mechanistic studies support the proposed aryne generation mechanism.

Does mandibular advancement with clear aligners have the same skeletal and dentoalveolar effects as traditional functional appliances?

BACKGROUND: The study aimed to compare the dentoskeletal effects of Vanbeek Activator, Herbst, Twin-Block and Mandibular Advancement with clear aligners in children with skeletal Class II malocclusions. METHODS: A sample with sixty-three patients (37 males, 26 females) was included and divided into untreated control group (C, n = 12), Vanbeek Activator group (V, n = 14), Herbst group (H, n = 11), Twin-Block group (TB, n = 12) and MA group (MA, n = 14). Cephalometric analysis and Johnston Pitchfork analysis were performed to quantify the skeletal and dentoalveolar components in molar relationship and overjet correction. Compare the differences of cephalometric data and Johnston-analysis data. RESULTS: The treatment changes showed significant differences in SNB, FH-NP, NA-PA, Co-Go, Co-Pog, ANB, lower facial height ratio, U1-PP, U6-PP, L1-MP and U1-L1. All the appliances improved overjet relationships significantly (Vanbeek, Herbst, Twin-Block and MA were 2.77 mm, 5.53 mm, 4.73 mm and 3.66 mm respectively) with significant retraction of maxillary incisors. The lower incisor displacement of group V and MA was negative, while that of group H and TB was positive and there were significant differences. Molar relationships were also improved by 3.45 mm, 6.85 mm, 3.48 mm and 0.92 mm for Vanbeek, Herbst, Twin-Block and MA. Mandible displacement showed a trend of group H > TB > V > MA. The displacement of maxillary molars in group H was greater than that in group C, TB and MA, and that of mandibular ones was greater than that in group C, V and MA, significantly. Herbst, Twin-Block and MA have more significant dentoalveolar effect than Vanbeek, while Vanbeek has more skeletal effect than the others especially in restraining maxillary growth. CONCLUSIONS: Four appliances are all effective in mandibular advancement, modification of class II molar relationship and deep overjet, with unavoidable increase in lower facial ratio. Vanbeek Activator has the most skeletal effects. Vanbeek and MA have a good control of mandibular incisors while more compensatory lower incisors proclination in Herbst and Twin-Block. Herbst has greater maxillary molar distalization. MA allows aligning and leveling meanwhile leading the mandible forward.

Relationship between EMG features and force in orbicularis oris muscle.

BACKGROUND: Lip incompetence resulting from mouth breathing is a common clinical manifestation, while there are no definite indicators of amplitude and intensity of muscle functional training in clinical practice, which leads to unsatisfactory training results. OBJECTIVE: The aim was to quantify the relationship between electromyography (EMG) and force in orbicularis oris muscle, so that the indicators of muscle functional training can be evaluated using EMG signals, so as to improve the training effects. METHODS: The EMG and the force signals of orbicularis oris muscle from 0% to 100% MVC within 5 s in twelve healthy subjects (six males and six females; age, 25 ± 2 years; mass, 60 ± 15 kg) were recorded simultaneously for three trials. Four EMG features consisting of RMS, WAMP, SampEn and FuzzyEn were analyzed. The regression analyses were performed using first-order and third-order polynomial model. RESULTS: There were high correlations between the four EMG features and muscle force with the two models. The third-order model yielded a higher coefficient of determination (R2) than the linear model (p< 0.001) and the result of FuzzyEn (R2: 0.884 ± 0.059) was the highest in the four features. CONCLUSION: The third-order model with FuzzyEn of EMG signals may be used to guide the muscle functional training.