Application of Medical Statistical and Machine Learning Methods in the Age Estimation of Living Individuals.

In the study of age estimation in living individuals, a lot of data needs to be analyzed by mathematical statistics, and reasonable medical statistical methods play an important role in data design and analysis. The selection of accurate and appropriate statistical methods is one of the key factors affecting the quality of research results. This paper reviews the principles and applicable principles of the commonly used medical statistical methods such as descriptive statistics, difference analysis, consistency test and multivariate statistical analysis, as well as machine learning methods such as shallow learning and deep learning in the age estimation research of living individuals, and summarizes the relevance and application prospects between medical statistical methods and machine learning methods. This paper aims to provide technical guidance for the age estimation research of living individuals to obtain more scientific and accurate results.

Dental age estimation based on the radiographic visibility of the periodontal ligament in the lower third molars: application of a new stage classification.

The purpose of the present study was to test whether a new stage classification based on radiographic visibility of the periodontal ligament in lower third molars in a Chinese population can be used for the 18- and 21-year thresholds. A total of 1300 orthopantomograms, including equal numbers of northern Chinese males and females evenly distributed between the ages of 15 and 40 years, were analyzed. The stages were defined according to the visibility of periodontal ligament for the outer parts of lower third molar roots because the visibility status of the periodontal ligament between the roots of lower third molars is none valuable in many Chinese individuals. Stage 0 was first achieved at the age of 17.05 years in males and 17.46 years in females. The earliest appearance of stage 1 was 17.47 years in males and 17.86 years in females. Stage 2 was first observed in males at the age of 21.43 years and in females at the age of 21.96 years. The onset of stage 3 was first observed at the age of 25.83 years in males and 23.14 years in females. Compared with the stage classification of Olze et al., which also considers the mesial parts of the roots, the number of assessable cases could be significantly increased. Therefore, our novel approach is effective for age estimation in the Chinese population.

Third molar maturity index (I3M) for assessing age of majority in northern Chinese population.

In many countries, assessment of legal age, also known as age of majority, has become increasingly important over the years. In China, individuals older than 18 years of age have full capacity regarding civil conduct and can be tried as an adult for criminal charges. Therefore, from a legal point of view, it is crucial to determine whether an individual is an adult. The developmental degree of the third molar is widely recognized as a suitable site for age estimation in late adolescence. This article uses the third molar maturity index (I3M) with a cutoff value of I3M = 0.08, which was established by Cameriere et al. in 2008, to distinguish whether an individual is a minor or an adult (≥ 18 years of age) in a northern Chinese population. A total of 840 digital orthopantomograms (OPTs) from 420 male and 420 female northern Chinese subjects aged 12 to 25 years were evaluated. It was found that an increase in I3M corresponded to a decrease in chronological age. In our study, I3M = 0.10 showed better accuracy in age discrimination in both men and women. This threshold also resulted in high sensitivity (0.929 and 0.809) and specificity (0.940 and 0.973) in males and females, respectively. The proportion of correctly classified subjects was 0.917 (95% CI, 0.898 to 0.935) in total, 0.938 (95% CI, 0.915 to 0.961) in male and 0.895 (95% CI, 0.866 to 0.925) in female subjects. Bayes post-test probabilities were 0.967 (95% CI, 0.947 to 0.986) in males and 0.983 (95% CI, 0.966 to 0.998) in females. These differences in threshold values between Chinese and Caucasian populations might be because the development of third molars is delayed in the Chinese population compared to the Caucasian population. In conclusion, I3M might be a useful method in legal and forensic practices to determine ages in late adolescence in northern Chinese individuals. However, a specific population should be tested before I3M is used for legal age estimation.

In vitro evaluation of the impact of a bioceramic root canal sealer on the mechanical properties of tooth roots.

Bacground/purpose: Endodontically treated teeth are more prone to vertical root fracture with the mechanical property changes to some extent during root canal treatment. This study aimed to investigate the effects of a bioceramic sealer on the mechanical properties of tooth roots. Materials and methods: Dentin discs were dried by two different methods (ethanol drying and paper points drying) and then filled with a BC sealer named iRoot SP. SEM and EDS were used to analyze the newly formed minerals in dentin tubules. Elastic modulus and hardness of the secondary dentin in areas proximal to the primary dentin (PD-SD) and areas proximal to canal or iRoot SP (SD-C/SD-iRoot SP) were measured using nanoindentation technique. The compressive strength of roots filled with iRoot SP were tested by compressive loading test. Results: (1) Penetration and mineralization: Paper points drying was more conducive to iRoot SP adhesion, spreading and penetration into the dentin tubules than 95% ethanol drying. (2) Micromechanical properties: After filling root canal with iRoot SP, the elastic modulus and hardness of SD-iRoot SP were higher than those of PD-SD (P = 0.001 and P = 0.000). (3) Fracture resistance: The compressive strength of the roots filled with iRoot SP was not significantly different from that of the roots unprepared and unfilled (P = 0.957), but was higher than that of the roots prepared and unfilled (P = 0.009). Conclusion: Excessive drying (95% ethanol drying method) is not conducive to the penetration and mineralization of the BC sealer iRoot SP into dentin tubules. The good bioactivity of iRoot SP was responsible for increasing the elastic modulus and hardness of dentin, which strengthened the prepared roots.

Exercise for Trismus Prevention in Patients with Head and Neck Cancer: A Network Meta-Analysis of Randomized Controlled Trials.

A common side effect of managing head and neck cancer is trismus, which devastates patients' quality of life. The purpose of this study was to investigate prophylactic exercise interventions for preventing trismus and difficulty in mouth opening in head and neck cancer. Five databases were searched for randomized controlled trials. Network meta-analysis was performed with risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). This study finally included 11 randomized controlled trials (n = 805). Trismus risk in patients who received exercise with phone call follow up (E + P) was significantly lower than those received usual care (RR = 0.42; 95% CI: 0.29 to 0.61) and exercise alone (RR = 0.33; 95% CI: 0.18 to 6.22). Mouth opening in usual care was significantly lower than in the tri-integrated strategy group (MD = 15.22; 95% CI: 8.88 to 21.56). Exercise is recommended for preserving mouth opening distance in patients with head and neck cancer. Tri-integrated strategies could be an effective method for preventing trismus.

Exogenous melatonin positively regulates lignin biosynthesis in Camellia sinensis.

Melatonin (MT) is a bioactive molecule that can regulate various developmental processes. Changes in lignin content play important roles in plant growth and development. Herein, quantitative analysis and histochemical staining showed that lignin content significantly increased over time, and melatonin treatment triggered the lignification at 8 and 16 d in tea leaves. The POD activity participated in lignin formation had also been significantly improved. The effect of melatonin on the increase of lignin content was attenuation over time. Sequencing results based on transcriptome at 8 and 16 d showed that 5273 and 3019 differentially expressed genes (DEGs) were identified in CK1 vs. MT1 and CK2 vs. MT2, respectively. A total of 67 DEGs were annotated to lignin biosynthesis, and 38 and 9 genes were significantly up-regulated under melatonin treatment, respectively. Some transcription factor genes such as MYB were also identified among the two pairwise comparisons, which might relate to lignin metabolism. Melatonin increased the degree of lignification in tea leaves by modifying the enzyme genes expression involved in lignin synthesis pathway. These results provide a reference for further study on the molecular mechanism of the dynamic changes of lignin content induced by melatonin treatment in tea plants.

Cytokinin (6-benzylaminopurine) elevates lignification and the expression of genes involved in lignin biosynthesis of carrot.

Carrot is a root crop consumed worldwide and has great nutritional qualities. It is considered as one of the ten most important vegetable crops. Cytokinins are an essential class of the plant hormones that regulate many processes of plant growth. Till now, the effects of cytokinin, BAP, on lignin biosynthesis and related gene expression profiles in carrot taproot is unclear. In order to investigate the effect of applied BAP on lignin-related gene expression profiles, lignin accumulation, anatomical structures, and morphological characters in carrot taproots. Carrot roots were treated with different concentrations of BAP (0, 10, 20, and 30 mg L-1). The results showed that the application of BAP significantly increased plant length, shoot fresh weight, root fresh weight, and taproot diameter. In addition, BAP at 20 mg L-1 or 30 mg L-1 enhanced the average number of petioles. BAP treatment led to increased number and width of xylem vessels. The parenchyma cell numbers of pith were significantly induced in taproots treated with the BAP at a concentration of 30 mg L-1. BAP significantly upregulated most of the expression levels of lignin biosynthesis genes, caused elevated lignin accumulation in carrot taproots. Our results indicate that BAP may play important roles in growth development and lignification in carrot taproots. Our results provide a valuable database for more studies, which may focus on the regulation of root lignification via controlling cytokinin levels in carrot taproots.

DcBAS1, a Carrot Brassinosteroid Catabolism Gene, Modulates Cellulose Synthesis.

Brassinosteroids (BRs) are important phytohormones and play critical roles during the growth and development of the plant. Numerous studies on biosynthesis and the signaling pathway of BRs have been performed, while the report about the metabolism of BRs is limited to carrots. In this study, we identified a homologous gene of AtCYP734A1/BAS1 (DCAR_009214), named DcBAS1, from carrots based on the data of the genome. The Arabidopsis overexpression line hosting the DcBAS1 gene was a dwarf and had crinkled blades and shortened petioles. Exogenous BL treatment rescued its growth and stem elongation. In addition, overexpressing DcBAS1 inhibited the cellulose synthesis in transgenic Arabidopsis plants. Results of quantitative real-time polymerase chain reaction revealed that overexpression of DcBAS1 inhibited the expression levels of AtCESAs genes (AtCESA1, AtCESA3, and AtCESA6), which are involved in cellulose synthesis in primary cell walls. AtBES1, which can be active by BR signaling, was also inhibited. These results revealed that DcBAS1 is the important gene involved in BR metabolism in carrots. Overexpression of DcBAS1 reduced the level of endogenous BRs and inhibited the cellulose synthesis in transgenic Arabidopsis plants.

Exogenous brassinosteroids altered cell length, gibberellin content, and cellulose deposition in promoting carrot petiole elongation.

Brassinosteroid (BR) is a predominant plant hormone in regulating cell elongation and cell size. BR-deficient mutants display reduced plant growth and dwarfism in Arabidopsis and rice. In carrot, BRs promote petiole elongation, but its underlying mechanism involving exogenous BR remains unknown. Here, weighted gene co-expression network analysis and promoter region analysis were adopted to identify the potential genes that interacted with DcBZR1/BES1. Bioactive gibberellin (GA) level and cellulose deposition were also determined in the control and treated plants. Quantitative real-time PCR was performed to detect the expression profiles of GA biosynthesis-related genes, GA signaling genes, and cellulose synthase genes. Bioactive GA level and cellulose deposition were upregulated after the petioles were treated with 24-epibrassinolide (24-EBL). The most putative DcBZR1/BES1 genes were clustered in yellow module. The expression level of DCAR_009411 (a GA5-like gene) was significantly induced after 3 h of treatment. The expression levels of DCAR_019754 and DCAR_013973 (CESA-like genes) were also significantly induced after 3 h of 24-EBL treatment. Our results suggested that the effect of BR on carrot petiole growth was quick. These results also provided potential insights into the mechanism by which BRs modulate GA and cellulose synthesis to promote cell elongation in carrot petioles.

DcC4H and DcPER Are Important in Dynamic Changes of Lignin Content in Carrot Roots under Elevated Carbon Dioxide Stress.

In our study, isobaric tags for relative and absolute quantification (iTRAQ) was conducted to determine the significantly changed proteins in the fleshy roots of carrots under different carbon dioxide (CO2) treatments. A total of 1523 proteins were identified, of which 257 were differentially expressed proteins (DEPs). On the basis of annotation analysis, the DEPs were identified to be involved in energy metabolism, carbohydrate metabolism, and some other metabolic processes. DcC4H and DcPER, two lignin-related proteins, were identified from the DEPs. Under elevated CO2 stress, both carrot lignin content and the expression profiles of lignin biosynthesis genes changed significantly. The protein-protein interactions among lignin-related enzymes proved the importance of DcC4H and DcPER. The results of our study provided potential new insights into the molecular mechanism of lignin content changes in carrot roots under elevated CO2 stress.

Risk factors for infective endocarditis in children with congenital heart diseases - A nationwide population-based case control study.

BACKGROUND: Infective endocarditis (IE) is uncommon in childhood. Its associated epidemiological characteristics in patients with congenital heart disease (CHD) remain unclear. METHODS: The study population included children born in Taiwan during the years 1997 to 2005 who were diagnosed as having CHD before 3years of age. All children were followed up until the end year of 2010, the diagnosis of infective endocarditis, or death. The demographic characteristics of patients with and without IE, the invasive procedures performed during 6months before the index date, the prophylactic antibiotics related to dental procedures, and in-hospital mortality were collected. RESULTS: Information of 24,729 children with CHD were retrieved for our analysis and 237 patients with newly diagnosed IE were identified. The incidence rate of IE in all CHD lesions was 11.13 per 10,000person-years. Taking ASD for reference, the following CHD lesions were at risk for IE: cyanotic CHD (adjusted OR, 9.58; 95% confidence interval, 5.38-17.05), endocardial cushion defect (ECD) (8.01; 2.73-23.50), Left-sided lesions (4.36; 1.90-10.01) and VSD (2.93; 1.64-5.23). Patients who underwent procedures have a higher risk of acquiring IE which include central venous catheter (CVC) insertion (3.17; 2.36-4.27), cardiac catheterization (3.74; 2.67-5.22), open-heart surgery (2.47; 1.61-3.77), valve surgery (3.20; 1.70-6.02), and shunt surgery (7.43; 2.36-23.41). However, dental procedures did not increase the risk of IE, irrespective of antibiotic usage. CONCLUSIONS: The risk of IE varies markedly among CHD lesions in our study. Invasive heart procedures but not dental procedures, are more significantly associated with IE among children with CHD.