Assessing alfalfa (Medicago sativa L.) tolerance to salinity at seedling stage and screening of the salinity tolerance traits

Salt is among the most harmful agents that negatively influences crop yield. Alfalfa is an important perennial forage crop that exhibits wide cultivar variations in salt tolerance. Developing salt-tolerant alfalfa plants is a promising way to utilize salinized land. A comprehensive method was developed to achieve reliable and effective evaluation of alfalfa salt resistance. This included principal components, membership functions and cluster and stepwise regression analyses. These were used to analyse the salt tolerance coefficients of 14 traits and to evaluate 20 diverse alfalfa cultivars at the seedling stage. The various morphological root parameters of six alfalfa cultivars with contrasting salt tolerance were also tested by a scanning apparatus. According to the comprehensive evaluation value (D value), one highly salt-tolerant, two salt-tolerant, four moderately salt-tolerant and 13 salt-sensitive alfalfa cultivars were screened. A mathematical equation for the evaluation of alfalfa salt tolerance was established: D' = -0.126 + 0.667SFW + 0.377SDW + 1.089K⁺ /Na⁺  + 0.172SFW/RFW (R²  = 0.988; average forecast accuracy of 96.95%), where four indices were closely related to the salt tolerance: shoot fresh weight, ratio of shoot fresh weight to root fresh weight, shoot dry weight and ratio of K⁺ to Na⁺ in the shoot. We also found that SSA correlated strongly with SFW, SDW, K⁺ /Na⁺ , D values, while SRV correlated obviously with SFW, SFW/RFW and D values after 150 mm NaCl treatment. In conclusion, the SFW, K⁺ /Na⁺ , SDW, SFW/RFW, SSA and SRV could be used as indicators of salt tolerance in alfalfa seedlings grown under 150 mm NaCl treatment.

Dual Orbital Degeneracy Lifting in a Strongly Correlated Electron System

The local structure of NaTiSi_{2}O_{6} is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the transition. The analysis unravels that, on warming, the dimers evolve into a short range orbital degeneracy lifted (ODL) state of dual orbital character, persisting up to at least 490 K. The ODL state is correlated over the length scale spanning ∼6 sites of the Ti zigzag chains. Results imply that the ODL phenomenology extends to strongly correlated electron systems.

Physics-informed machine learning: case studies for weather and climate modelling

Machine learning (ML) provides novel and powerful ways of accurately and efficiently recognizing complex patterns, emulating nonlinear dynamics, and predicting the spatio-temporal evolution of weather and climate processes. Off-the-shelf ML models, however, do not necessarily obey the fundamental governing laws of physical systems, nor do they generalize well to scenarios on which they have not been trained. We survey systematic approaches to incorporating physics and domain knowledge into ML models and distill these approaches into broad categories. Through 10 case studies, we show how these approaches have been used successfully for emulating, downscaling, and forecasting weather and climate processes. The accomplishments of these studies include greater physical consistency, reduced training time, improved data efficiency, and better generalization. Finally, we synthesize the lessons learned and identify scientific, diagnostic, computational, and resource challenges for developing truly robust and reliable physics-informed ML models for weather and climate processes. This article is part of the theme issue 'Machine learning for weather and climate modelling'.

Factors Affecting Trends in Societal Indicators of Ageing Well in Hong Kong: Policies, Politics and Pandemics

OBJECTIVES

To document the trend in a quality of life indicator for the older Hong Kong population as an assessment of the impact of age friendly city policies, political conflicts and the covid-19 pandemic.

DESIGN

Random telephone survey and collection of government data over four years (2017-2020).

SETTING

Community living older people.

PARTICIPANTS

People aged 50 years and over.

MEASUREMENTS

The Hong Kong Quality of Life Index covering four domains of in income security, health status, capability and enabling environment.

RESULTS

From 2017-9, improvements were seen in various domains in parallel with the adoption of the World Health Organization's Age Friendly City concept by government policy together with a territory wide initiative supported by a major philanthropic organization. However scores of all domains dropped markedly as a result of political conflicts as well as the onset of the pandemic.

CONCLUSION

The documentation of the trend in HKEQOL shows that while it may be used as a macro indicator that is able to reflect policies affecting the well-being of older people, it is also able to reflect the impact of societal unrest and pandemics, and that the latter may override the effect of existing ageing policies. It also follows that during social unrest and pandemics, specific policies targeting older people may be needed to maintain well-being.

Validation of the Construct of Intrinsic Capacity in a Longitudinal Chinese Cohort

OBJECTIVES

We examined the structure and predictive ability of intrinsic capacity in a cohort of Chinese older adults.

METHODS

We used data from the MrOS and MsOS (Hong Kong) study, which was designed to examine the determinants of osteoporotic fractures and health in older Chinese adults. We analysed baseline and the 7-year follow-up data using exploratory factor analysis, confirmatory factor analysis (CFA), and mediation analysis.

RESULTS

The study consisted of 3736 participants at baseline (mean 72.2 years), with 1475 in the 7-year follow-up. Bi-factor CFA revealed five sub-factors labelled as 'cognitive', 'locomotor', 'vitality', 'sensory', and 'psychological' and one general factor labelled as 'intrinsic capacity'. The model fits the data well, with Root Mean Square Error of Approximation (RMSEA)=0.055 (90% CI=0.053-0.058) for the 5-factor model and RMSEA=0.031 (90% CI=0.028-0.035) for the bi-factor model. Significantly lower intrinsic capacity scores were found in older age groups, women, as well as those who had lower levels of education, lower subjective social status, reported more chronic diseases, or a higher number of IADL limitations (All p<0.0001). Intrinsic capacity had a direct effect in predicting incident IADL limitations at the 7-year follow-up (β=-0.21, p<0.001). The effect was larger than the direct effect of the number of chronic diseases on incident IADL limitations (β=0.05, not significant).

CONCLUSIONS

This study supports the construct and predictive validity of the proposed capacity domains of intrinsic capacity. The findings could inform the development of an intrinsic capacity score that would facilitate implementation of the concept of intrinsic capacity in clinical practice.

Neighborhood Social Cohesion Associates with Loneliness Differently among Older People According to Subjective Social Status

OBJECTIVES

To examine whether neighborhood social cohesion can alleviate the negative impact of low subjective social status on feelings of loneliness.

DESIGN

Cross-sectional study.

SETTING

Community, Hong Kong.

PARTICIPANTS

Older people who participated in a cohort study on osteoporosis and general health in Hong Kong (MrOs study).

METHODS

Data were sourced from the 14-year follow-up data of the MrOs study. Loneliness was measured using the 6-item De Jong Gierveld Loneliness Scale. Neighborhood social cohesion was measured by the Hong Kong version of Neighborhood Cohesion Instrument. Linear regression models were used to examine the associations between neighborhood social cohesion and loneliness, controlled for age, sex, marital status, educational level, lifestyle, number of diseases, and maximum lifetime income. The analyses were stratified by subjective social status as measured by a 10-rung self-anchoring scale.

RESULTS

1,037 participants with a mean age of 83 years were included in the study, of whom 72%, 83%, and 64% were classified as at risk of overall loneliness, emotional loneliness, and social loneliness, respectively. Those who were classified as at risk of overall loneliness reported lower subjective social status and had lower levels of neighborhood social cohesion. Linear regression models showed that higher levels of neighborhood social cohesion were associated with lower levels of overall and social loneliness. Stratified analyses showed that the associations between neighborhood social cohesion and loneliness vary across subjective social status groups. Among those with low/middle social status ranking, higher levels of neighborhood social cohesion were associated with lower overall (low-ranking B=-0.111, p=0.001; middle-ranking B=-0.057, p=0.026) and social (low-ranking B=-0.093, p<0.001; middle-ranking B=-0.073, p<0.001) loneliness scores. Among those with high ranking, higher levels of neighborhood social cohesion were associated with lower overall (B=-0.099, p=0.041) and emotional (B=-0.056, p=0.017) loneliness scores, but the associations became insignificant when controlling for maximum lifetime income.

CONCLUSIONS AND IMPLICATIONS

Neighborhood social cohesion may operate differently in different social ranking groups. Interventions to alleviate feelings of loneliness should be subjective social status specific.

Increased expression of CXCL2 in ACPA-positive rheumatoid arthritis and its role in osteoclastogenesis

Anti-citrullinated protein/peptide antibodies (ACPA) play important roles in the pathogenesis of rheumatoid arthritis (RA). ACPA-positive (ACPA⁺ ) and ACPA-negative (ACPA^- ) RA were suggested to be different disease subsets, with distinct differences in genetic variation and clinical outcomes. The aims of the present study were to compare gene expression profiles in ACPA⁺ and ACPA^- RA, and to identify novel candidate gene signatures that might serve as therapeutic targets. Comprehensive transcriptome analysis of peripheral blood mononuclear cells (PBMCs) from ACPA⁺ and ACPA^- RA patients and healthy controls was performed via RNA sequencing. A validation cohort was used to further investigate differentially expressed genes via polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Spearman's correlation test was used to evaluate the correlation of differentially expressed genes and the clinical and laboratory data of the patients. The role of differentially expressed genes in osteoclastogenesis was further investigated. Expression of C-X-C motif chemokine ligand 2 (CXCL2) was significantly increased in ACPA⁺ RA than in ACPA^- RA, which was validated in PBMCs and serum. CXCL2 promoted the migration of CD14⁺ monocytes and increased osteoclastogenesis in RA patients. RAW264.7 macrophages were used to investigate specific mechanisms, and the results suggested that CXCL2 stimulated osteoclastogenesis via extracellular receptor kinase (ERK) mitogen-activated protein kinase (MAPK) and nuclear factor kappa B pathways. In conclusion, CXCL2 was highly expressed in ACPA⁺ RA than in ACPA^- RA. CXCL2 promoted osteoclastogenesis and was related to bone erosion in RA, which suggests that the blockade of CXCL2 might be a novel strategy for the treatment of RA.

[Study on the expression of non-coding microRNA-376b-3p in serum exosomes of patients with malignant glioma and the mechanism of anti-angiogenesis]

Objective: To screen the different microRNAs in the serum exosomes of patients with malignant glioma, to explore the effect of non-coding microRNA-376b-3p (miR-376b-3p) on the proliferation, invasion and tumor vasculogenic mimicry of glioma cells, and to verify its targeting effect on HOXD10. Methods: HiSeq/MiSeq high-throughput sequencing was used to screen the different microRNA expression profiles, target genes and action pathways in the serum exosomes of patients with malignant glioma. Samples were used to evaluate the expression of candidate microRNAs in serum exosomes of high-grade gliomas. The effects of miR-376b-3p on the proliferation, invasion and angiogenesis of glioma cells were detected by MTT assay, Transwell migration assay and Matrigel vasculogenic mimicry assay. The mRNA and protein expression of HOXD10 were detected to evaluate the regulatory effect of miR-376b-3p on it. Results: There were 144 different expression microRNAs in the serum exosomes between malignant glioma and the normal control. Focal adhesion and tumor protein polysaccharides were involved in the regulation of glioma enriched by KEGG(Kyoto Encyclopedia of Genes and Genomes). MiR-376b-3p was down regulated in malignant glioma, and AUC of malignant glioma was 0.85 (P<0.01). MTT test showed that the proliferation ability of miR-376b-3p inhibitor group was higher than that of the control group, and that of miR-376b-3p mimic group was lower than that of the control group. Transwell migration test showed that the number of transmembrane cells in miR-376b-3p inhibitor group was higher than that in NC inhibitor group, and the number of transmembrane cells in miR-376b-3p mimic group was lower than that in NC mimic group. The number of tubes of vasculogenic mimicry in miR-376b-3p mimic group was lower than that in NC mimic group. MiR-376b-3p inhibitor decreased the expression level of HOXD10 mRNA and protein, and miR-376b-3p mimic increased the expression level of HOXD10 mRNA and protein. Conclusions: MiR-376b-3p is down-regulated in the serum exosomes of malignant glioma patients. The up-regulated miR-376b-3p can reduce the proliferation and invasion of glioma cells, inhibit the formation of vasculogenic mimicry, and increase the expression of HOXD10, which is expected to inhibit the formation of two forms of angiogenesis at the same time. MiR-376b-3p may be a new therapeutic target of anti-angiogenesis for malignant glioma.

Polymorphisms rs763110 in FASL is linked to hepatitis C virus infection among high-risk populations

BACKGROUND

The Fas cell surface death receptor (FAS) and Fas ligand (FASL) can participate in the apoptosis of immune cells and target cells infected with a virus through the FAS-FASL signalling pathway. The decoy receptor 3 (DCR3) can competitively inhibit the binding of FAS to FASL. Our aim is to investigate the effect of single nucleotide polymorphisms (SNPs) in FAS, FASL and DCR3 on hepatitis C virus (HCV) infection.

METHODS

Four SNPs (rs763110 in FASL, rs1324551 and rs2234767 in FAS and rs2257440 in DCR3) were genotyped in 1495 controls free of HCV, 522 individuals with spontaneous HCV clearance and 732 patients with hepatitis C virus infection. The RegulomeDB database and RNAfold web servers were used to explore potential biological functions of SNPs.

RESULTS

FASL rs763110 was associated with susceptibility to HCV infection, and not to CHC. The odds ratio (95% confidence interval) of HCV infection in high-risk populations carrying FASL rs763110-TT was 1.82 (1.36-2.51, P < 0.001) compared to that of CC genotypes and 1.93 (1.43-2.60, P < 0.001) higher than that of CC + CT genotypes. Based on computer simulation, FASL rs763110-T may affect the transcription of mRNA by affecting the binding of a transcription factor, leading to structural changes in mRNA.

CONCLUSION

The genetic variant in FASL is linked with HCV infection, but not to spontaneous HCV clearance.

Older Adults' Perspective towards Participation in a Multicomponent Frailty Prevention Program: A Qualitative Study

OBJECTIVES

This study aimed to explore pre-frail and frail older Chinese people's perspectives on a multi-component, group-based frailty prevention program in Hong Kong, along with their views regarding factors determining participation and sustainability of such program.

DESIGN

Seven focus groups were conducted.

SETTING

Community elderly centres.

PARTICIPANTS

A total of 38 community-dwelling older people aged 54 - 84 (mean age, 64.9 years; female, 58%; married, 68%; retired, 97%) screened with pre-frailty or frailty completing a 12-week multi-component (involving physical, cognitive, and social activities), group-based frailty prevention program were interviewed.

MEASUREMENTS

Thematic analysis was conducted.

RESULTS

Using thematic analysis, perceived health benefits, peer support and social networking were identified as key motivators concerning intention to participate in the frailty prevention program; whereas perceived health benefits, socializing, sense of connectedness, expert guidance and sense of dignity were identified as key motivators concerning program adherence.

CONCLUSION

Majority of participants provided positive feedbacks about the multi-component intervention program in regards to their physical health, psychological well-being and social life. These findings highlighted several important factors for consideration in future design of frailty interventions regarding the needs of pre-frail and frail older adults, which could help to motivate and sustain their participation in community-based frailty prevention programs.

Directional massless Dirac fermions in a layered van der Waals material with one-dimensional long-range order

One or a few layers of van der Waals (vdW) materials are promising for applications in nanoscale electronics. Established properties include high mobility in graphene, a large direct gap in monolayer MoS₂, the quantum spin Hall effect in monolayer WTe₂ and so on. These exciting properties arise from electron quantum confinement in the two-dimensional limit. Here, we use angle-resolved photoemission spectroscopy to reveal directional massless Dirac fermions due to one-dimensional confinement of carriers in the layered vdW material NbSi_0.45Te₂. The one-dimensional directional massless Dirac fermions are protected by non-symmorphic symmetry, and emerge from a stripe-like structural modulation with long-range translational symmetry only along the stripe direction as we show using scanning tunnelling microscopy. Our work not only provides a playground for investigating further the properties of directional massless Dirac fermions, but also introduces a unique component with one-dimensional long-range order for engineering nano-electronic devices based on heterostructures of vdW materials.

How Much Money Is Enough? Poverty and Health in Older People

OBJECTIVES

We examined the relationship between absolute income, adequacy of disposable income, and self-rated health among participants aged 60 years and over.

DESIGN

Cross sectional study.

SETTING

Community living older people in Hong Kong.

PARTICIPANTS

Older people aged 60 years and over in five districts in Hong Kong.

MEASUREMENTS

Data from a cross sectional survey of age friendly characteristics across five districts of Hong Kong carried out using stratified random sampling across a broad range of socioeconomic attributes.

RESULTS

Self-rated health showed a gradient for both absolute and adequacy of disposable income. The OR for the association between having just enough, or insufficient disposable income and poor health was higher: 2.0 and 3.6 respectively, and higher than that for absolute income (OR 1.8), and remained significant after adjustment for absolute income. No association between absolute income and self-rated health was observed among women. These findings suggest that adequacy of disposable income provide a stronger association with self-rated health compared with absolute income among older people aged 60 years and over, particularly for women. The absolute income corresponding to what is considered adequate disposable income lies between HK$4000-10000.

CONCLUSION

Adequacy of disposable income may be a better indicator than absolute income for older people in examining the relationship with health outcomes, particularly for older women.

Prognostic value of the pretreatment albumin:globulin ratio combined with adult comorbidity evaluation 27 and TMN staging in patients with squamous cell carcinoma of the maxillary sinus

The albumin:globulin (A:G) ratio, adult comorbidity evaluation 27 (ACE-27), and TMN staging have been shown to be strong predictive indicators of the survival of patients with many types of tumours. We have investigated the prognostic value of pretreatment based on the A:G ratio combined with TMN staging and ACE-27 in patients with squamous cell carcinoma (SCC) of the maxillary sinus. We studied 196 patients, and the prognostic value was explored by univariate and multivariate Cox's hazards analysis. Multivariate analyses suggested that pretreatment A:G ratio was independently associated with overall survival (hazard ratio (HR) 1.542, 95% CI 1.219 to 1.991, p=0.002); disease-specific survival, (HR 1.499, 95% CI 1.197 to 1.842, p=0.001); and disease-free survival (HR 1.452, 95% CI 1.207 to 1.834, p<0.001). Additional prognostic factors shown in the survival analyses included ACE-27, pathological T stage, and pathological N stage. Pretreatment A:G ratio combined with ACE-27 and TMN staging were powerful prognostic indicators of outcome in patients with SCC of the maxillary sinus, which has potentially important ramifications for stratification of the disease in the future.

[Diagnostic value of gadobenate dimeglumine enhanced MRI in hepatic fibrosis of rats]

Objective: To evaluate the value of Gd-BOPTA enhanced MRI in the staging of liver fibrosis. Method: Fifty male SD rats (6-week-old, 180-220 g) were divided into the modeling group (n=42) and the control group (n=8). The model of liver fibrosis in the modeling group was established by carbon tetrachloride (animal license No. SYXK (Su) 2017-0043). From week 2 to week 10, rats in the modeling group (n=4) and control group (n=1) were randomly selected to scan 1 h(RER1), 2 h(RER2) and 3 h(RER3) after injection of Gd-BOPTA, respectively, to measure the relative enhancement rate (RER) of liver parenchyma. The shape of intrahepatic bile duct and the degree of enhancement at each time point were observed. Results: Forty-two rats (34 rats in the modeling group and 8 rats in the control group) completed the experiment. RER1, RER2 and RER3 of the control group were 1.44±0.37, 1.22±0.37 and 0.84±0.28 respectively. RER1, RER2 and RER3 of the modeling group were respectively: S1 (n=6): 1.49±0.48, 1.29±0.39, 0.91±0.38;S2 (n=9): 1.48±0.44, 1.34±0.37, 1.04±0.40;S3 (n=11): 1.49±0.43, 1.37±0.39, 1.21±0.30; S4 (n=8): 1.49±0.44, 1.40±0.37, 1.24±0.40. There was no significant difference in RER1 and RER2 values between the control group and the liver fibrosis group (F=0.022, P=0.999; F=0.301, P=0.875). There were significant differences between the control group and RER3 values of hepatic fibrosis stage S3 and S4 (t=2.249, P=0.031; t=2.274, P=0.029), there was no significant difference between the remaining groups (all P>0.05).In the control group, the intrahepatic bile duct was obviously strengthened within 1 hour after enhancement, and walked naturally. The intrahepatic bile duct was slightly enhanced 1h after the enhancement of S3-S4 stage of hepatic fibrosis, and the intrahepatic bile duct was significantly enhanced 2-3 hours later, with distorted alignment. Conclusion: Delayed 3 hours liver parenchymal RER and intrahepatic bile duct distortion delay enhancement after Gd-BOPTA enhancement contribute to the S3-S4 diagnosis of liver fibrosis.