Environmental implications of agricultural abandonment on Fe cycling: Insight from iron forms and stable isotope composition in karst soil, southwest China.

Land-use change influences the fate of nutrient elements, including iron (Fe), and then threaten soil security. In this study, Fe forms and stable isotope composition (δ56Fe) in soils were investigated to identify the variations in the processes of Fe cycling during agricultural abandonment in a karst region of Southwest China. Soil δ56Fe compositions varied from -0.05‰-0.02‰ in croplands, 0.05‰-0.12‰ in abandoned croplands, to 0.30‰-0.80‰ in the native vegetation lands. In the croplands, Fe oxidation-precipitation process is considered as the main contributor to Fe migration and isotope fractionation, leading to a relatively enrichment of heavier Fe isotope in deeper soil layer. In the abandoned croplands and native vegetation lands, Fe isotope in the organic-rich layer (0-10 cm) was significantly lighter than that in subsurface layer (20-30 cm), mainly due to the recovery of soil organic carbon (SOC) and macro-aggregate after cropland abandonment. Moreover, the eluviation process mainly caused a decrease in soil Fe contents and enrichment of heavy Fe isotope in deeper soils (below 40 cm). The positive correlation between oxidized Fe and SOC contents suggested the accumulation of mobile Fe in soils after agricultural abandonment, which is beneficial for Fe uptake and assimilation by plants. This study suggests that agricultural abandonment significantly reduce soil Fe leaching loss and improve plant Fe supply by SOC accumulation in surface soil, which gives an environmental implication for the management of soil nutrients.

Discovery and identification of a series of alkyl decalin isomers in petroleum geological samples.

The comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS) has been used to characterize a crude oil and a source rock extract sample. During the process, a series of pairwise components between monocyclic alkanes and mono-aromatics have been discovered. After tentative assignments of decahydronaphthalene isomers, a series of alkyl decalin isomers have been synthesized and used for identification and validation of these petroleum compounds. From both the MS and chromatography information, these pairwise compounds were identified as 2-alkyl-decahydronaphthalenes and 1-alkyl-decahydronaphthalenes. The polarity of 1-alkyl-decahydronaphthalenes was stronger. Their long chain alkyl substituent groups may be due to bacterial transformation or different oil cracking events. This systematic profiling of alkyl-decahydronaphthalene isomers provides further understanding and recognition of these potential petroleum biomarkers.

Forensic Medical Assessment for Neurologic Erectile Dysfunction: 58 Case Reports.

To introduce the approaches and procedures of neurologic erectile dysfunction (ED) assessment in our institute, and evaluate the neurologic investigation by making an analysis of 58 cases. Diagnostic criteria of neurologic ED: nervous system injuries or diseases, abnormal clinical symptoms and signs, electrophysiological abnormalities of nervous system, abnormal results of nocturnal penile tumescence and rigidity (NPTR) (penis rigidity <60% and lasting time <10 minutes). In the group of 20 patients with the injuries of the brain, spinal cord or spinal root nerves, pudendal cortical somatic evoked potential (PCSEP), sacral reflex latency (SRL), pudendal-to-cortical motor evoked potential (PCMEP), penile sym- pathetic skin responses (PSSR) and NPTR showed abnormality by 45%, 20%, 20%, 85% and 85%, re- spectively. In 38 patients with the injuries of pelvic fracture with urethra break, PCSEP, SRL, PCMEP, PSSR and NPTR showed abnormality by 24%, 5%, 20%, 92% and 66%, respectively. In the former, 35% were identified to have severe ED, and 50%, moderate ED; in the latter, 21%, to have severe ED, 13%, medium ED, and 37%, light ED. The approaches and procedures were proved to possess excellent specificity and reliability in the assessment of neurological ED.

[Automated assessment of developmental levels of epiphysis by support vector machine].

OBJECTIVE: To realize the automated assessment of the levels of epiphysis of distal radius and ulna by support vector machine (SVM). METHODS: The X-ray films of the left wrist joints were taken from 140 teenagers aged from 11 to 19 years old as training samples. The levels of epiphysis of distal radius and ulna were divided into five developmental levels. Each level contained 28 samples. Another 35 cases were selected as independent verifying samples. SVM classification models of the five developmental levels of epiphysis of distal radius and ulna were established. The internal cross validation was made by leave one out cross validation (LOOCV), while the external validation was made by histogram of oriented gradient (HOG), and then the accuracy (PA) of testing results was calculated, respectively. RESULTS: The PA of SVM, LOOCV and HOG of distal radius epiphyseal level were 100%, 78.6%, and 82.8%, respectively; whereas the PA of SVM, LOOCV and HOG of distal ulna epiphyseal level were 100.0%, 80.0% and 88.6%, respectively. CONCLUSION: The SVM-based automatic models of the growth stage of distal ra- dius and ulna appear to have certain feasibility, and may provide a foundation for software development of bone age assessment by forensic medicine.

[Coronary angiography of in vitro porcine heart using MSCT].

OBJECTIVE: To establish standardized methods and parameters of the isolated heart coronary angiography through the experiment of in vitro porcine heart by MSCT. METHODS: Based on different perfusion volume (50, 60 and 70 mL) and different perfusion-imaging time (5, 10 and 20 min), the in vitro porcine coronary artery was injected liposoluble and water-soluble contrast agents using remodel angiography equipment and scanned by MSCT. And the 3D image results were compared. The images were recorded and evaluated by 2 radiologists and analyzed by statistical software. RESULTS: Liposoluble contrast agent affected the images by damaging and infiltrating the fats around the coronary artery, while the water-soluble contrast agent didn't affect the images. The groups with 60 mL or 70 mL perfusion and 5 min perfusion-imaging time had the best images. CONCLUSION: The suitable parameters of the angiography lay the foundation of postmortem coronary angiography.

Geochemical Characteristics of Trace Elements and Mineralization Model of the Ediacaran-Early Cambrian Phosphorites, South China.

As a nonrenewable resource, phosphate rock is an important support for the development and survival of the national economy. The regional distribution and output of phosphate rock in China are extremely uneven, and the amount of high-quality ore resources is relatively poor, which seriously restricts the development and utilization of phosphate rock resources in China. This paper briefly summarizes the distribution characteristics of phosphate rock resources and summarizes the characteristics and research progress of Ediacaran-early Cambrian phosphorus mineralization types, geological characteristics, and deposit genesis of the Yangtze platform in South China. The Ediacaran-early Cambrian sedimentary phosphorite deposits in China are mainly distributed in Yunnan, Guizhou, Hubei, Sichuan and Hunan provinces of the Yangtze platform, in which the early Cambrian phosphate deposits are also rich in rare earth elements, associated with uranium, nickel, molybdenum, vanadium, and other beneficial metal elements. The increase of atmospheric oxygen content at the Ediacaran-Cambrian boundary may have promoted the extensive oxygenation of the late Neoproterozoic oceans, so the Ediacaran-early Cambrian oceans generally showed a reductive environment, and there may be dynamic chemical stratification of the oxidation zone-sulfide zone-iron zone. Up to the early Cambrian, the redox stratified structure of Precambrian seawater may still be inherited, showing that the surface water is an oxidizing environment, changing to a reduction environment, and even wedge-shaped sulfide water is developed at the bottom of the deep basin. The main phosphorus sources are deep phosphorus-rich seawater, continental weathering, and deep hydrothermal activity of Ediacaran-early Cambrian marine sedimentary phosphorite deposits in South China. The genetic mechanisms of phosphorite deposits in the Yangtze platform in South China are mainly biogenic, upwelling phosphorus-forming theory, mechanical mineralization, and syn-sedimentary hot water mixed genesis. In the future, it is still necessary to further explore the internal relationship between phosphorus deposits and major geological events, the in situ analysis of microstructure of phosphate rock ores, and the genetic mechanism of phosphate deposits and the reconstruction of paleo-marine environment.

Paleo-marine redox environment fluctuation during the early Cambrian: Insight from iron isotope in the Tarim Basin, China.

The Ediacaran to Cambrian period is generally considered to be the vital transition in the history of marine redox environment and life evolution on earth. The ocean oxygenation levels during this transition period are still debated. Since iron is widely involved in biogeochemical cycles and undergoes redox cycling both in the seawater and sediments, it has become a significant proxy to reconstruct paleo-marine environment. In order to constrain the paleo-marine redox state in the early Cambrian, the iron isotope composition of bulk rock (δ56FeT) is interpreted combining with iron-speciation, redox sensitive elements and pyrite sulfur isotope (δ34Spy) of Yuertusi Formation in Tarim Block. The δ56FeT values varies from -0.39 ‰ to 0.48 ‰, with an average of 0.07 ‰, mainly controlled by pyrite mineral facies in this study. Based on the mechanism of pyrite generation in different redox condition, it is proposed that the marine environment of the lower Cambrian in the Tarim basin is dominated by anoxic with intermittent euxinic state. The dynamic evolution of redox environment can be divided into three intervals. The gradual decrease of δ56Fe in Interval I indicates the paleo-marine environment changed from anoxic ferruginous to euxinic, and the paleo-marine sulfate reservoir decreased to a limited level, which might be attributed to abundant burial of organic matter and pyrite. For Interval II, δ56Fe values first increase to evident positive because of partial oxidization then decreased to that of seawater (about 0 ‰) due to complete oxidization. In Interval III, the continuous decrease of δ56Fe values infers a sustaining oxidization. In summary, the paleo-marine environment of the lower Cambrian Yuertusi Formation evolved from anoxic ferruginous to euxinic and then oxidized continuous. Iron isotope statistics from geological historical periods indicate that seawater was relatively oxidized after the NOE event but did not reach the oxidation levels of present-day seawater.

Electroretinogram and histopathologic changes of the retina after methanol intoxication.

In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication, 35 rats were divided randomly into five groups administrated with saline, 3-day high dose, 7-day high dose, 3-day low dose and 7-day low dose methanol separately. The retinal function of each group was assessed by flash electroretinogram (F-ERG) 3 and 7 days after methanol poisoning. The microstructure and ultrastructure of the retina were observed at the same time. The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning, which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG. These injuries were aggravated 7 days after poisoning. Meanwhile, the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning, but there were no further worsening tendency 7 days after poisoning. The retinal histological analysis showed cellular edema, heteromorphy and disarrangement, tissular loosen of the inner nuclear layer and photoreceptors layer. The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer. The low-dose methanol intoxication only caused transient damage of the retina. Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells. The mitochondrial damage developed from outer layer to inner layer of the retina.

[The staging method of sternal end of clavicle epiphyseal growth by thin layer CT scan and imaging reconstruction].

OBJECTIVE: To establish a CT staging method of sternal end of clavicle epiphyseal growth for teenagers by thin layer CT scan, multiplanar reconstruction (MPR) and volume reconstruction (VR) technologies. METHODS: The CT imaging characteristics, which collected from 460 teenagers (aged from 15 to 25) in East and South China, were studied through both sternal ends of clavicles' imagings by thin layer coronal CT scan and axial CT scan, MPR and VR technologies. The parameters of sternal end of clavicle including the longest diameter of epiphysis, the longest diameter of metaphysis, their length ratio, area of epiphysis, area of metaphysis, and their area ratio were measured and calculated in order to establish new classification. RESULTS: Based on the staging method of Schmeling, integrating the CT imaging reconstruction information of sternal end of clavicle, the new classification of sternal end of clavicle epiphyseal growth were divided into 1 to 5 stages, and stage 2 and stage 3, respectively, contained a, b and c sub-classification. CONCLUSION: This new classification has merits of large sample size, wide age range and easy operability. By using CT imaging reconstruction techniques and analyzing the data which closely related to sternal end of clavicle epiphyseal growth of teenagers, the feasibility of the staging method could be increased.

[Bone development trend in the knee joint of Tibetan teenagers in Aba Prefecture of Sichuan Province].

OBJECTIVE: To discuss bone development trend in the knee joint of Tibetan teenagers in Sichuan province and to effectively update the database for estimating the living age of Tibetan teenagers in terms of bone age of the knee joint. METHODS: Radiographs including epiphysis of distal femur, proximal tibia and proximal fibula were taken from 483 Tibetan male and female teenagers aged from 14 to 19 years old in Aba prefecture of Sichuan province in order to observe epiphyseal growth situation. The descriptive data of the epiphyseal closure ages of these teenagers' knee joints were statistically analyzed by SPSS 16.0 software. RESULTS: The distal femur epiphyseal closure occurred earliest, while the proximal fibula epiphyseal closure occurred latest. The epiphyseal growth of knee joints of females occurred about one year earlier than that of males. CONCLUSION: The forensic information and data related to Tibetan teenagers' bone age identification should be updated regularly. These results provide potential value for the practice of forensic medicine, anthropology and clinical medicine.

Mathematical models for teenager's living age evaluation based on CT image of medial clavicular epiphysis.

OBJECTIVE: To explore the correlation between volume rendering (VR) statistics of medial clavicular epiphysis and living age, and establish the mathematical models for living age evaluation using the CT image of medial clavicular epiphysis based on the growth rules of osteoepiphysis of medial clavicle. METHODS: The CT images of the medial clavicles from 795 teenagers aged 15-25, 387 males and 408 females, were collected in East and South China. VR 3D images were reconstructed from 0.60 mm-thick slice CT images. The epiphyseal diameter, sternal end diameter, and their respective diameter ratio (the left: X1; the right: x3); epiphyseal area, sternal end area, and their respective area ratio (the left: x2; the right: x4), were measured and calculated. All these observations were analyzed using SPSS 19.0 statistical software. The statistical differences in gender and age were analyzed by Mann-Whitney U test. The mathematical models were established using least square. Sixty trained subjects, 30 males and 30 females, were tested to verify the accuracy of the established mathematical models. RESULTS: In the group of same age, x1 showed significant difference in gender; the same results were observed in x2, x3, and x4, which suggested that the growth rules of osteoepiphysis of medial clavicle were highly correlated with living age. The accuracy of these mathematical models were all above 67.6% (+/- 1.0 year) and 78.5% (+/- 1.5 year). CONCLUSION: The mathematical models with reasonable accuracy could be manageable in practice to confirm the conclusion of the atlas method. The current study can contribute to the single skeletal age evaluation.

[Progress in thin layer CT scan technology in estimating skeletal age of sternal end of clavicle].

It is practical value for determination the teenagers whether the age is full of the legal responsibility age of 18 years old or not by estimating skeletal age of sternal end of clavicle. The traditional methods mainly based on X-ray radiography. However, sternal end of clavicle and adjacent lung, bronchus, sternum, rib, transverse process of thoracic vertebra are overlapped each other. As a result of overlapping, there will be obtained false negative or positive film reading results when according to X-ray observation of epiphyseal growth of sternal end of clavicle, which directly affect the scientificalness and accuracy of estimating of skeletal age. In recent years, the scholars at home and abroad have started to use thin layer CT scan technology to estimate skeletal age of the sternal end of clavicle. With the 2D and 3D CT recombination technology, the accuracy of the film reading distinctly improves by making the shape, size and position of epiphysis displayed clearly. This article reviews the application and research progress of thin layer CT scanning technology in estimating skeletal age of sternal end of clavicle at home and abroad, analyzes the superiority and value of thin layer CT scan technology, which applied to skeletal age of sternal end of clavicle.

Reliability study on quantitative detection of extensor digitorum brevis strength with needle electromyography and nerve conduction.

OBJECTIVE: To study the objectivity and reliability of needle electromyography and nerve conduction for detection of musculus extensor digitorum brevis strength, which may provide a basis for establishing a quantitative detection of muscle strength in forensic clinical study. METHODS: Forty-four healthy people were enrolled as the subjects, and during toe dorsiflexion, the following items including needle electromyography indexes, motor unit potential (MUP) amplitude, MUP count, recruitment reaction type, and nerve conduction detection indexes, compound muscle action potential (CMAP) amplitude, CMAP latent period and motor nerve conduction velocity (MNCV), were simultaneously detected under the cooperation and disguise condition. RESULTS: Under the cooperation condition, regardless of the same operator or different operators, there were good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, while there were normal test-retest reliabilities in MUP count and recruitment reaction type and the repeatability of the same operator was slightly better than the repeatability between different operators. Under the disguise condition, test-retest reliabilities of MUP amplitude, CMAP amplitude, CMAP latent period and MNCV were relatively high, while test-retest reliabilities of MUP count and recruitment reaction type were relatively low. CONCLUSION: There are good test-retest reliabilities in MUP amplitude, CMAP amplitude, CMAP latent period and MNCV, which can be conducive to comparison between different operators and results at various times; MUP count and recruitment reaction type, which can be easily affected by subjectivity of operators and examinees, can be used to differentiate whether an examinee disguises or not. The indexes used to objectively judge muscle strength remain to be further investigated.

[Application of MSCT's coronary artery calcification score in evaluation of sudden death caused by coronary artery disease].

OBJECTIVE: To access application value of multi-slice spiral computed tomography (MSCT) and coronary artery calcium scoring (CACS) in investigation the coronary artery disease (CAD), and to explore the effective way of virtual autopsy to evaluate the sudden death due to CAD. METHODS: Nine cases of sudden cardiac death were collected to analyze MSCT before the autopsy. The quantitative analysis of the degree of coronary artery calcium was made by Agatston's method. The CACS of all the subjects were calculated based on the diagnostic criteria for CAD, in which calcium scoring was more than 400. The results of CACS were compared with that of the autopsy. RESULTS: Only 2 cases got the high calcium scoring which were more than 400 in the 9 cases died of CAD confirmed by the autopsy. The prediction rate of CACS for CAD was only 22.2%. Pulmonary edema of different severity was found in both autopsy and MSCT. There was a higher morbidity rate in the left anterior descending of coronary artery than the other branches. CONCLUSION: Obvious calcification of coronary artery can be detected by MSCT and calculating CACS. To detect subtle calcification needs other technologies such as postmortem angiography.

Land-use conversion controls on the mobility of Zn in paddy soils revealed by stable Zn isotopes.

Understanding Zn biogeochemical cycling is necessary for monitoring Zn supply for plants and life during land use conversion, which is critical for environmentally sustainable development. But little is known about how the conversion of paddy soil to abandoned land affects the Zn isotope signature. A comparative field observation was conducted in northeast Thailand to investigate the Zn isotope footprint of paddy soils and abandoned paddy soils (PL and NPL). Our results show that Zn (τZnint : 0.04) slightly retains on PL, but is lost from NPL (τZnint from - 0.81 to - 0.24) to the river during weathering. Compared to PL (Δ66Znparent-soil: -0.29 ‰), more 66Zn isotopes might enter the river when rice cultivation ceases in NPL (Δ66Znparent-soil from -0.26 ‰ to -0.47 ‰). Rice harvest and then root decay might result in heavy 66Zn isotopes accumulating at the topmost soil in PL (δ66Zn: 0.14 ‰) and short-term abandonment (1-2 years) in paddy soils (NPL1 δ66Zn: 0.18 ‰). The release of assimilated Zn, and then the high adsorption of Zn in the Fe-SOM-metal(loid)s ternary system positively contribute to the high [Zn] in PL, while this was not observed in NPL. Our findings provide a comprehensive insight into the Zn isotope signature in response to the conversion of land-use types, which is beneficial for understanding the terrestrial Zn geochemical cycle.

New insights into the dolomitization and dissolution mechanisms of dolomite-calcite (104)/(110) crystal boundary: An implication to geologic carbon sequestration process.

Geologic carbon sequestration (GCS) is a promising strategy to reduce the harm of CO2 due to the rapidly increased fossil fuel combustion. Dolomitization and dissolution processes of deeply buried carbonate reservoirs significantly impact the potential of GCS. However, previous investigations mainly focus on the macroscopic batch experiments, the mechanisms at atomic level are still unclear especially for crystal boundary, but urgently required. Herein, the GCS potential and the effects of boundary dissolution on calcite and dolomite were investigated based on both analytical and simulation methods such as molecular dynamics simulation (MDS) and density functional theory (DFT) calculations, to deeply unveil the mechanisms of dolomitization and formation of intergranular secondary pores from the atomic perspective. The morphology results indicated that the dissolution of calcite and dolomite in carbonic acid solution started via the edges and corners. In addition, the simulated results showed that the carbon sequestration potential presented an order in dolomite (PMg50%) > PMg40% > PMg30% > PMg20% > PMg10% > calcite by dolomitization due to the reduced bulk volume but increased lattice stress. Furthermore, both electrons transfer and diffusion coefficients results suggested that the (104)/(110) boundary was preferentially dissolved as compared to the (104) and (110) planes, indicating that crystal boundary was beneficial to the formation of pores for the oil and gas storage, but harmful to the stability of long-term GCS. Therefore, this study, for the first time, provides new insights into uncovering the mechanisms of the GCS process in depth, from an atomic level focusing on the crystal boundary, thereby promoting the understand of the long-term evolution for both calcite and dolomite in deep reservoirs.

Interface dissolution kinetics and porosity formation of calcite and dolomite (110) and (104) planes: An implication to the stability of geologic carbon sequestration.

Geologic carbon sequestration (GCS) via injecting CO2 into deep carbonate reservoirs (mainly calcite and dolomite) is a promising strategy to reduce CO2 level. However, the dissolution or precipitation of calcite/dolomite planes on minerals/solution interface during long-term GCS process develops intergranular porosity and thus affects the permeability and stability of reservoirs. To investigate this process, both calcite and dolomite were dissolved in acetic and carbonic acids. A diffusion-controlled process was identified, with greater diffusion rates in acetic acid than that in carbonic acid. Quantified planes activity of both minerals follows (110) > (116) > (101) > (113) > (018) > (104) through density functional theory. Accomplished with preferential dissolution of calcite (110) planes in carbonic acid, calcite crystals precipitated with (104) planes at 423.15 K, under which, more calcite crystals were observed on dolomite surface, producing Ca-deplete surface. Molecular dynamic calculations showed higher dissolution rates of calcite/dolomite (110) planes than (104). In addition, the dissolution coefficients of Ca2+ were approximately triple of that Mg2+. Therefore, this study reveals the interface dissolution mechanisms of calcite and dolomite, especially on (110) and (104) planes at an atomic level, for the first time, providing better understanding for the stability of long-term GCS process.

Iron isotope fractionation of redox and geochemical cycling in the typical Gleysols in Mun River Basin, Northeast Thailand.

Iron (Fe) isotope is a potential tool for tracking redox process and geochemical cycling in terrestrial environment. In this study, Fe concentration and its isotopic composition (δ56Fe) in two typical Gleysol profiles (M1 and M2) were investigated to distinguish the processes which influence the variation of Fe isotopic composition during redox regimes in the Mun River Basin (MRB). Under oxidizing condition, Fe(II) was oxidized and re-precipitated to form Fe(III) (hydr)oxides zone (Fe nodule-containing zone) in two Gleysol profiles, leading to extremely light Fe isotopes in these zones. The results revealed that the lowest δ56Fe value in Fe(III) (hydr)oxides zone was derived from the migration of light Fe isotopes in upper zone, and Fe(II) was retained and oxidized to Fe(III) (hydr)oxides. Proton-promoted dissolution and leaching were two critical factors leading to a decrease in Fe concentration, which were accompanied by the accumulation of heavy Fe isotopes in the upper zone of M1 profile. In M2 profile, light Fe induced by soil organic matter was accumulated in the topsoil with abundant organic matter. These findings provide comprehensive information of Fe isotopic fractionation and Fe cycling in soil profiles, which would contribute to the understanding of biogeochemical elemental cycling in terrestrial ecosystems.

[Progress in diagnosis of neurogenic erectile dysfunction].

Recently, with application of evoked potentials technology in the test of somatic and autonomic nerves, quantitative sensory testing in the detection of small nerve fiber function, and functional magnetic resonance imaging in the detection of senior central function, the detection of neural function has become more accurate. This article reviews the progress and application of diagnostic methods about neurogenic erectile dysfunction in order to provide a reference for forensic diagnosis and research in the future.

Long-term trend of bone development in the contemporary teenagers of Chinese Han nationality.

OBJECTIVE: To further improve the accuracy of bone age identification using the time of secondary ossification center appearance and epiphyseal fusion of 7 joints to estimate the age of living individuals. METHODS: DR films were taken from 7 parts including sternal end of clavical and the left side of shoulder, elbow, carpal, hip, knee and ankle joints of 1 709 individuals who came from eastern China, central China and southern China, whose ages were between 11.0 and 20.0 years. From those 7 joints 24 osteal loci were selected as bone age indexes, which could better reflect age growth of teenagers. The characteristics of secondary ossification center appearance and epiphyseal fusion were observed, and the mean and age range of secondary ossification center appearance and epiphyseal fusion were calculated. RESULTS: The fusion time of the 24 epiphyses were advanced at different degrees, the most obvious epiphyses the sternal end of clavicle, scapular acromial end, distal end of the radius, distal end of the ulna, iliac crest, ischial tuberosity, the upper and lower end of tibia and fibula. The appearance time of sternal end of clavicle, scapular acromial end, iliac crest and ischial tuberosity epiphyses were all found to be after the age of 12, and the female's age, approximately 1 year ahead of schedule in comparison with the male's. CONCLUSION: The relevant forensic information and data for bone age identification should be updated every 10-15 years so as to provide accurate and objective evidence for court testimony, conviction and sentencing.