Twenty kinds of amino acids are simplified into 3 types: hydrophobic amino acids (H), hydrophilic amino acids (P) and neutral amino acids (N). Each residue is reduced to a bead which locates in the position of the C?琢 atom. The off-lattice model is adopted and the relative entropy is used as a minimization function to predict the tertiary structure of a protein. A new contact intensity function is given to consist with protein design research based on the relative entropy. Testing on several real proteins from Protein Data Bank (PDB) shows the good results obtained with the model and method. The root mean square deviations (RMSD) of the predicted structures relative to the native structures range from 0.30 to 0.70 nm. A foundation for studying protein design using the HNP model and the relative entropy was made.

The application of the protein design method based on the HNP model and the relative entropy theory is discussed for four structural classes of real proteins, and the results are compared with that of the HP model. Testing on 190 proteins shows that this method is generally effective for the different structural classes of proteins. Further studies show that the success rate of this method on regular secondary structures is higher than that on the random coil. Additionally, the success rate for different types of amino acids is also analyzed. It is found that the success rate on the hydrophilic residues is higher than those of the other two types. Furthermore, the success rate of this method on the conserved residues is higher than the non-conserved residues. The reasons resulting in the difference of the success rate on different systems were also analyzed. All analyses mentioned above make the foundation for the development and the application of this method in the future.

Adolescent ; Adult ; China ; epidemiology ; Humans ; Middle Aged ; Motor Activity ; Rural Population ; Suburban Population ; Urban Population

Objective: To analyze the status of dietary sodium intake of Chinese adult residents in fifteen provinces in 2015. Methods: Data were collected from 2015 China Nutrition Transition Cohort Study. This cohort study used a three consecutive 24-h retrospective method to record food intake and weighing method to record household condiment consumption. In this study, 14 847 residents aged 18 years and over with complete data from 15 provinces in 2015 were selected for the comparison of dietary sodium intake (median) with different characteristics. Results: Among the 14 847 residents, 47.1% were males, and the rural and northern residents accounted for 60.1% and 37.7%, respectively. Median sodium intake was 3 960.0 mg/d among residents in 2015. The sodium intake of males (4 272.1 mg/d) was higher than that of females (3 716.6 mg/d). Across age subgroups, sodium intake was highest among residents aged 45-59 years (4 257.0 mg/d; 18-44 years old, 3 867.1 mg/d; ≥60 years old, 3 799.0 mg/d). Sodium intake was higher in rural area (4 042.9 mg/d) than in urban area (3 866.8 mg/d), higher in north (4 229.2 mg/d) than in south (3 806.8 mg/d) (all P values <0.05). 11.8% of residents with dietary sodium intake were below 2 000 mg/d. The main sources of dietary sodium were condiments (79.4%), regular cooking foods (11.9%) and processed foods (8.7%). Among the condiments, the salt and soy sauce accounted for 63.6% and 10.4%, respectively. Conclusion In 2015, Chinese adult residents had higher dietary sodium intake with gender and regional differences. Condiments were the main source of dietary sodium.

Objective To analyze the status of dietary sodium intake of Chinese adult residents in fifteen provinces in 2015. Methods Data were collected from 2015 China Nutrition Transition Cohort Study. This cohort study used a three consecutive 24?h retrospective method to record food intake and weighing method to record household condiment consumption. In this study, 14 847 residents aged 18 years and over with complete data from 15 provinces in 2015 were selected for the comparison of dietary sodium intake (median) with different characteristics. Results Among the 14 847 residents, 47.1% were males, and the rural and northern residents accounted for 60.1% and 37.7%, respectively. Median sodium intake was 3 960.0 mg/d among residents in 2015. The sodium intake of males (4 272.1 mg/d) was higher than that of females (3 716.6 mg/d). Across age subgroups, sodium intake was highest among residents aged 45-59 years (4 257.0 mg/d; 18-44 years old, 3 867.1 mg/d; ≥60 years old, 3 799.0 mg/d). Sodium intake was higher in rural area (4 042.9 mg/d) than in urban area (3 866.8 mg/d), higher in north (4 229.2 mg/d) than in south (3 806.8 mg/d) (all P values<0.05). 11.8% of residents with dietary sodium intake were below 2 000 mg/d. The main sources of dietary sodium were condiments (79.4%), regular cooking foods (11.9%) and processed foods (8.7%). Among the condiments, the salt and soy sauce accounted for 63.6% and 10.4%, respectively. Conclusion In 2015, Chinese adult residents had higher dietary sodium intake with gender and regional differences. Condiments were the main source of dietary sodium.

Objective To analyze the status of dietary sodium intake of Chinese adult residents in fifteen provinces in 2015. Methods Data were collected from 2015 China Nutrition Transition Cohort Study. This cohort study used a three consecutive 24?h retrospective method to record food intake and weighing method to record household condiment consumption. In this study, 14 847 residents aged 18 years and over with complete data from 15 provinces in 2015 were selected for the comparison of dietary sodium intake (median) with different characteristics. Results Among the 14 847 residents, 47.1% were males, and the rural and northern residents accounted for 60.1% and 37.7%, respectively. Median sodium intake was 3 960.0 mg/d among residents in 2015. The sodium intake of males (4 272.1 mg/d) was higher than that of females (3 716.6 mg/d). Across age subgroups, sodium intake was highest among residents aged 45-59 years (4 257.0 mg/d; 18-44 years old, 3 867.1 mg/d; ≥60 years old, 3 799.0 mg/d). Sodium intake was higher in rural area (4 042.9 mg/d) than in urban area (3 866.8 mg/d), higher in north (4 229.2 mg/d) than in south (3 806.8 mg/d) (all P values<0.05). 11.8% of residents with dietary sodium intake were below 2 000 mg/d. The main sources of dietary sodium were condiments (79.4%), regular cooking foods (11.9%) and processed foods (8.7%). Among the condiments, the salt and soy sauce accounted for 63.6% and 10.4%, respectively. Conclusion In 2015, Chinese adult residents had higher dietary sodium intake with gender and regional differences. Condiments were the main source of dietary sodium.

Background The decline of physical activity in the elderly due to aging may increase the risk of sarcopenia. Currently, there is a lack of evidence from large natural populations on the relationship between PA and sarcopenia. Objective To explore the relationship between PA and sarcopenia in the elderly aged 60 years and above in 10 provinces (autonomous regions) of China. Methods Data were retrieved from the 2022—2023 round of the China Development and Nutrition Health Impact Cohort. Personal basic information and PA data were collected by questionnaire survey. Skeletal muscle mass was measured by bio-electrical impedance analysis, muscle strength was measured using a grip dynamometer, and physical performance was reflected by 6-meter walk speed. The Asian Working Group for Sarcopenia (AWGS) 2019 criteria were used to diagnose sarcopenia. Light physical activity (LPA) duration, moderate-to-vigorous physical activity (MVPA) duration, and total physical activity volume were calculated. A total of 3326 residents aged ≥60 years with complete data were selected as the survey participants. Multiple logistic regression models and restricted cubic splines (RCS) were used to assess the association between PA duration/volume and sarcopenia. Results In 10 provinces (autonomous regions) of China, the prevalence of sarcopenia in the elderly aged 60 years and above was 5.5% (95%CI: 4.7%, 6.2%). The logistic regression analysis showed that compared with the elderly reporting 0-7.0 h·week⁻¹ in LPA duration, the risk of sarcopenia in the elderly with LPA duration of >14.0-21.0 h·week⁻¹ was reduced by 51% (OR=0.49, 95%CI: 0.26, 0.96). Compared with the elderly with total physical activity ≥15.0 metabolic equivalent of task (MET)-h·week⁻¹, those with <7.5 MET-h·week⁻¹ had a 2.24-fold increased risk of sarcopenia (OR=2.24, 95%CI: 1.17, 4.29). The RCS results found that LPA duration and total physical activity volume each showed a nonlinear dose-response relationship with the risk of sarcopenia (P_overall<0.05, P_non-linear<0.05). Compared with the elderly with an LPA duration of 0 h· week⁻¹, the risk of sarcopenia in the elderly with an LPA duration of 12.6 h· week⁻¹ was the lowest (OR=0.42, 95%CI: 0.21, 0.83). Compared with the elderly with a total physical activity volume of 15.0 MET-h· week⁻¹, the elderly with a total physical activity volume of 46.0 MET-h· week⁻¹ had the lowest risk of sarcopenia (OR=0.57, 95%CI: 0.38, 0.84). There was no statistically significant association between weekly MVPA duration and the risk of sarcopenia (P>0.05). Conclusion Increasing weekly LPA duration and total physical activity volume would help to reduce the risk of sarcopenia.