The objective was to identify single nucleotide polymorphisms (SNPs) in exons of the osteoprotegerin gene and to analyze the relationship between the SNPs and bone mineral density in postmenopausal women. We used polymerase chain reaction (PCR) and direct sequencing methods to identify SNPs and genotypes in 205 postmenopausal women. BMD at the lumbar spine (L2-4) and femoral neck (FN) were measured by dual-energy X-ray absorptiometry (DEXA). Serum osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL) and urinary N-telopeptide of type I collagen (NTx) were also measured. In exon 1 of the OPG gene, we found the Lys3Asn SNP. In 205 postmenopausal women, the Asn-allele frequency was 26.0%, and the distribution of Lys3Asn genotypes was Lys-Lys 56.6%, Lys-Asn 34.6% and Asn-Asn 8.8%, respectively. BMD at the lumbar spine (L2-4) of the Asn-Asn genotype was significantly higher (9.5-12.6%) than Lys-Asn and Lys-Lys genotypes (P=0.012), with evidence for an allele dose effect (P=0.008). Results remained similar after adjustment for age and body mass index. The Lys3Asn polymorphism of the OPG gene alone accounted for 7.7% of the variance of the L2-4 BMD in a multiple regression model. Logistic regression analysis revealed that the OPG genotype Lys-Lys had a 2.7 times (95% CI: 0.83-9.11) greater risk for osteopenia/osteoporosis than the Asn-Asn genotype. The Lys3Asn polymorphism in the OPG gene is associated with L2-4 BMD in postmenopausal women. The Lys-allele is associated with lower BMD and an increased risk for osteoporosis.

a b s t r a c tPlastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg À 1 , respectively, in the soils and 1.53 and 2.10 mg kg À 1 , respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern.

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To find out which of the following parameters-serum levels of insulin-like growth factor 1 (IGF-1), osteoprotegerin (OPG), leptin, osteocalcin (OC), and urinary excretion of N-terminal telopeptide of type I collagen (NTx), can be used as an early marker for osteopenia/osteoporosis in women diagnosed by dual-energy X-ray absorptiometry (DXA), 282 premenopausal and 222 postmenopausal women aged 20-75 years were investigated by the measurement of bone mineral densities (BMDs) at lumbar spine (LS) and femoral neck (FN) by DXA, together with serum concentrations of IGF-1, OPG, leptin, OC, and urinary NTx. The characteristics of the earliest marker(s) were tested with the receiver operating characteristic (ROC) analysis. The area under the curve (AUC), sensitivity, and specificity parameters were determined. It was revealed that serum levels of IGF-1 and leptin changed the earliest, with both markers significantly decreasing (P < 0.0001) or increasing (P = 0.020), respectively, at age 30. However, in ROC analysis, IGF-1 was the only early parameter that had the capacity to differentiate the low bone mass/osteoporosis women from the normal ones (P < 0.0001). If the serum level of IGF-1 at 1.5 SD below its peak was adopted as a cutoff point, it could identify women with low bone mass/osteoporosis with a sensitivity of 73% and specificity of 67%. In the premenopausal women subgroup analysis, the low bone mass women (30/282, 10.6%) were older (38.2 +/- 1.7 vs. 34.5 +/- 0.5 years; P = 0.026), with lower serum levels of IGF-1 (215.1 +/- 22.4 vs. 278.8 +/- 9.4 ng/ml; P = 0.02) and less lean mass (33.1 +/- 0.6 vs. 34.8 +/- 0.2 kg; P = 0.010) than the normal ones. After controlling for age, the serum level of IGF-1 had a weak, but still significant, positive correlation with lean mass (r = 0.17, P < 0.001). In conclusion, measurement of serum IGF-1 in young women may help in the early identification of those at risk for developing low bone mass and osteoporosis.

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This study investigated the relative contribution of fat mass and lean mass to bone mineral density (BMD) in young and premenopausal healthy Chinese women. The study was performed in 282 young and premenopausal healthy women with regular menstrual cycles. The BMD at lumbar spine (L2-L4), total hip and total body, together with fat mass and lean mass were assessed by dual-energy X-ray absorptiometry (DXA); body height, weight, waist and hip circumference were also measured, and body mass index (BMI) and waist-hip ratio were calculated. Fat mass was a major determinant for BMI, BMI and lean mass were positively related to L2-L4, total hip and total body bone density ( P<0.001 for all), lean mass was the only independent factor contributing to BMD at L2-L4 (standardized coefficient beta=0.282, P<0.001), total hip (beta=0.336, P<0.001) and total body (beta=0.361, P<0.001) in multiple stepwise regression analysis. The correlation between BMI and BMD was improved after adjustment for fat mass, while decreased or even lost when lean mass was adjusted. These data suggested that in the Chinese population, lean mass is an important factor determining BMD in young and premenopausal women.

The serum level of total osteocalcin was positively associated with fat-free mass independent of age, fat mass, leptin, and other confounders in premenopausal women.

Fossil fuel resources (eg, coal, oil, and natural gas) exist in underground reservoirs, where discontinuities are widespread and influence the stability of rock structures. The mechanical behavior of jointed rock masses significantly affects the long‐term stability of rock engineering. A major challenge in this area is to link the time‐dependent deformation with damage influence induced by distribution of joints in rock masses. In this paper, a damage mechanical theory is adopted which deals with several groups of joints distributed in rock masses. Based on the geometrical distribution of joints, a damage model considering the influence of normal vector and area density of joints is used to describe the discontinuities. A damage rheological model for jointed rock masses is developed and programmed in the finite difference software FLAC3D, and an example of jointed rock masses is used to verify the validity of the model. The damage rheological model could predict the visco‐elastic strain which corresponds to primary creep property, visco‐plastic strain which corresponds to steady state creep property, and damage strain which reflects the damage effect of joints to rock masses. Finally, we use this model to predict the displacements and damage zones in the rock masses surrounding an underground opening.