Neutron scattering and neural-network quantum molecular dynamics investigation of the vibrations of ammonia along the solid-to-liquid transition.

Vibrational spectroscopy allows us to understand complex physical and chemical interactions of molecular crystals and liquids such as ammonia, which has recently emerged as a strong hydrogen fuel candidate to support a sustainable society. We report inelastic neutron scattering measurement of vibrational properties of ammonia along the solid-to-liquid phase transition with high enough resolution for direct comparisons to ab-initio simulations. Theoretical analysis reveals the essential role of nuclear quantum effects (NQEs) for correctly describing the intermolecular spectrum as well as high energy intramolecular N-H stretching modes. This is achieved by training neural network models using ab-initio path-integral molecular dynamics (PIMD) simulations, thereby encompassing large spatiotemporal trajectories required to resolve low energy dynamics while retaining NQEs. Our results not only establish the role of NQEs in ammonia but also provide general computational frameworks to study complex molecular systems with NQEs.

[Magnetic resonance imaging T2 mapping could reflect disease status in patients with dermatomyositis or polymyositis].

This study aimed to explore the value of magnetic resonance imaging (MRI) T2 mapping in the assessment of dermatomyositis (DM) and polymyositis (PM). Thirty-three confirmed cases (myosin group) and eight healthy volunteers (healthy control group) at the Department of Rheumatology and Immunology, the First Affiliated Hospital of Kunming Medical University, from October 2016 to December 2017, were collected and analyzed. Multiple parameters of the myosin group were quantified, including creatine kinase (CK), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement C3, and complement C4. Disease status was evaluated using a panel of tools: myositis disease activity assessment tool-muscle (MDAAT-muscle), myositis disease activity assessment tool-whole (MDAAT-all), health assessment questionnaire (HAQ), medical outcomes study health survey short form-36 item (SF-36), hand muscle strength test (MMT-8) score, and MRI T2 mapping of muscle (22 muscles in the pelvis and thighs) T2 values. The results showed that in the myositis group, the measurements for CK, ESR, CRP, complement C3, and complement C4 were 457.2 (165.6, 1 229.2) IU/L, 20 (10, 42) mm/1h, 3.25 (2.38, 10.07) mg/L, 0.90 (0.83, 1.06) g/L, and 0.18 (0.14, 0.23) g/L, respectively. The scores for MMT-8, MDAAT-muscle, MDAAT-all, HAQ, and SF-36 were 57.12±16.23, 5.34 (4.00, 6.00), 34.63±12.62, 1.55 (0.66, 2.59), and 44.66±7.98, respectively. T2 values were significantly higher in all 22 muscles of the pelvis and thighs of patients with DM or PM compared with the healthy controls [(54.99±11.60)ms vs. (36.62±1.66)ms, P<0.001], with the most severe lesions in the satrorius, iliopsoas, piriformis, gluteus minimus, and gluteus medius muscles. The total muscle T2 value in the myositis group was positively correlated with CK, MDAAT-muscle, MDAAT-all, and HAQ (r=0.461, 0.506, 0.347, and 0.510, respectively, all P<0.05). There was a negative correlation between complement C4, SF-36, and MMT-8 scores (r=-0.424, -0.549, and -0.686, respectively, all P<0.05). Collectively, the findings from this study suggest that MRI T2 mapping can objectively reflect the disease status of DM and PM.

[Analysis of the therapeutic efficacy and factors influencing sequential combination of nucleos(t)ide analogues with pegylated interferon alpha for 48~96 weeks in the treatment of patients with chronic hepatitis B].

Objective: To explore the therapeutic efficacy and factors influencing the sequential combination of nucleos(t)ide analogues (NAs) with pegylated interferon alpha (Peg-IFN-α) in the treatment of patients with chronic hepatitis B (CHB). Methods: 144 CHB cases with NAs treatment for more than 1 year, HBV DNA < 20 IU/ml, hepatitis B surface antigen (HBsAg) quantification < 3 000 IU/ml, treated with a sequential combination of Peg-IFN-α treatment for 48 to 96 weeks, and followed up were selected from the Fifth Medical Center of the PLA General Hospital between May 2018 and May 2020. Intention-to-treat analysis was used to measure the HBsAg clearance rate at 96 weeks. The Kaplan-Meier method was used to compute the cumulative HBsAg clearance rate at 96 weeks. Univariate and multivariate logistic regression were used to analyze the factors influencing HBsAg clearance at 48 weeks of sequential combination therapy. Univariate and multifactorial COX proportional hazard models were used to analyze the factors influencing HBsAg clearance following 96 weeks of prolonged PEG-IFN-α treatment. The receiver operating characteristic curve was used to assess the predictive value of factors influencing HBsAg clearance. A Mann-Whitney U test was used to compare the measurement data between groups. The count data was compared using the χ(2) test between groups. Results: 41 (28.47%) cases achieved HBsAg clearance at 48 weeks of sequential combination therapy. The HBsAg clearance rate at 96 weeks was 40.28% (58/144) by intention-to-treat analysis. The Kaplan-Meier method computed that the cumulative HBsAg clearance rate at 96 weeks was 68.90%. Multivariate logistic regression analysis showed that HBsAg quantification at baseline (OR = 0.090, 95%CI: 0.034-0.240, P < 0.001) and a 24-week drop in HBsAg level (OR = 7.788, 95%CI: 3.408-17.798, P < 0.001) were independent predictors of HBsAg clearance in CHB patients treated sequentially in combination with NAs and Peg-IFN-α for 48 weeks. Receiver operating characteristic curve analysis showed that the baseline HBsAg quantification [area under the receiver operating characteristic curve (AUC), 0.911, 95% CI: 0.852-0.952)] and 24-week drop in HBsAg level (AUC = 0.881, 95%CI: 0.814-0.930) had equally good predictive value for 48-week HBsAg clearance, but there was no statistically significant difference between the two (Z = 0.638, P = 0.523). The value of the combination of baseline HBsAg quantification and 24-week drop in HBsAg level (AUC = 0.981, 95%CI: 0.941-0.997) was superior to that of single baseline HBsAg quantification (Z = 3.017, P = 0.003) and 24-week drop in HBsAg level (Z = 3.214, P = 0.001) in predicting HBsAg clearance rate at 48 weeks. Multivariate COX proportional hazards model analysis showed that HBsAg quantification at 48 weeks (HR = 0.364, 95%CI: 0.176-0.752, P = 0.006) was an independent predictor of HBsAg clearance with a prolonged course to 96 weeks of Peg-IFN-α treatment. Conclusion: The HBsAg clearance rate can be accurately predicted with baseline HBsAg quantification combined with a 24-week drop in HBsAg level in patients with CHB who are treated with a sequential combination of NAs and Peg-IFN-α therapy for 48 weeks. Prolonging the course of Peg-IFN-α treatment can enhance the HBsAg clearance rate's capability. An independent predictor of HBsAg clearance is HBsAg quantification at 48 weeks of sequential combination therapy with a prolonged course of 96 weeks of Peg-IFN-α treatment.