[Progress in genetic epidemiology of non-syndromic cleft palate only]

One of the most common birth defects is cleft palate only (CPO) of which non-syndromic cleft palate only (NSCPO) accounts for 50%. NSCPO is a complex disease where multiple genes and environmental factors contribute to its risk. Unlike non-syndromic cleft lip with or without cleft palate (NSCL/P), previous genome-wide association studies only identified a few common genetic variations achieving genome-wide significance. This review summarizes the recent findings on genetic epidemiology of NSCPO. According to the current evidence, the candidate genes are divided into three categories: candidate genes with strong evidence, candidate genes with suggestive evidence, and candidate genes with inadequate evidence. The findings of epigenetic studies, the next generation sequencing studies, interaction analysis on NSCPO are also reviewed.

Percutaneous reduction and fixation technique for 4th metacarpal shaft fracture

The objective of this retrospective study was to introduce a percutaneous reduction and intermetacarpal K-wire fixation technique for the treatment of the 4th metacarpal shaft fracture. From January 2014 to February 2017, 25 patients with isolated closed 4th metacarpal shaft fracture (angulation > 30°, rotation > 5°, or shortening > 5 mm) were treated by percutaneous reduction and internal fixation. Assessment comprised total active motion, grip strength, dorsal prominence, and patient satisfaction. Bone healing was achieved in all patients. At a mean follow-up of 28 months (range, 25-32 months), total active range of motion averaged 98% of contralateral values (range, 88%-100%). There were 20 excellent and 5 good results. Grip strength averaged 97% of contralateral values (range, 88%-100%). Mean dorsal prominence on a 100-mm visual analogue scale was 0 (range, 0-1). Mean satisfaction rating on the Short Assessment of Patient Satisfaction 26 (range, 22-28). Percutaneous reduction and intermetacarpal K-wire fixation is a useful technique for treating 4th metacarpal shaft fracture, achieving stable and reliable fixation, with good hand function.

POS0452 SYNOVIAL MYELOID-STROMAL PATHOTYPE PREDICTS ONE-YEAR RADIOGRAPHIC PROGRESSION IN ACTIVE RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a heterogeneous disease with variable prognosis. The cellular composition in synovium is the driving force of joint destruction in RA, and the predictive values of histopathological assessments on the clinical outcomes of RA have been identified. However, current synovial histopathological assessments mainly focus on the infiltrated immunocytes to distinguish RA synovium into different synovial pathotypes. Whether addition of stromal cells improve the accuracy of histopathological assessments remains unknow.

Objectives:

To distinguish synovial pathotypes of RA based on intercellular connection and explore their predictive value on one-year radiographic progression.

Methods:

Active RA patients who underwent needle synovial biopsy at baseline were recruited from a real-world prospective cohort. Clinical data were evaluated at baseline and 1, 3, 6, 12 months. Histopathologic assessments included Krenn synovitis score and semiquantitative score of immunohistochemical staining for CD20, CD38, CD4, CD8, CD68, CD31 and CD90. Cluster analysis was used to distinguish synovial pathotypes. The primary outcome was one-year radiographic progression defined as a change in total Sharp/van der Heijde modified score≥0.5 units.

Results:

1. Among 134 RA patients who received synovial biopsy at baseline and finished one-year follow-up, 105 had qualified synovial tissue. The mean age was 50.2±13.3 years with 77.1% female. The median disease duration was 24 (9-120) months. All patients were active RA, and 64.8%, 26.7% and 8.6% patients in high, moderate and low disease activity, respectively. There were 41 (39%) patients who have never been treated with corticosteroids or disease-modifying anti-rheumatic drugs.

2. During one-year follow-up, there were 48.6%, 63.8%, 71.4%, and 69.5% patients achieved CDAI LDA target, and 12.4%, 30.5%, 34.3%, and 32.4% patients achieved CDAI remission after 1, 3, 6, and 12 months, respectively. A total of 33 (31.4%) patients had radiographic progression.

3. All patients were divided into three clusters using cluster analysis based on the seven synovial cellular scores. Patients in cluster 1 (n=50, 47.6%) had higher scores of sublining CD68+ macrophages, CD31+ endothelial cells and CD90+ fibroblasts, thus named as myeloid-stromal pathotype. Patients in cluster 2 (n=26, 24.8%) had higher scores of CD20+ B cells, CD38+ plasma cells, CD4+ T cells and CD8+ T cells, thus named as lymphoid pathotype. Patients in cluster 3 (n=29, 27.6%) had lower scores of all seven cell types, thus named as pauci-cellular pathotype (Figure 1).

4. RA patients with baseline synovial myeloid-stromal pathotype showed higher rate of one-year radiographic progression versus lymphoid and pauci-cellular pathotypes (48% vs. 16.4%, P<0.001), whereas there was no difference between lymphoid and pauci-cellular pathotypes (11.5% vs. 20.7, P=0.475). Adjusted for confounding factors including age, sex, smoking, disease duration, RF status, ACPA status, CDAI, HAQ-DI and mTSS at baseline, multivariate logistic regression analysis showed that baseline synovial myeloid-stromal pathotype independently predicted one-year radiographic progression (AOR=3.602, 95%CI:1.257-10.324, P=0.017, Table 1).

Conclusion:

Baseline synovial myeloid-stromal pathotype in RA can predict one-year radiographic progression.

Funding:

This work was supported by National Natural Science Foundation of China (no. 81971527, 81801606 and 81801605), Guangdong Natural Science Foundation (no. 2018A030313541 and 2018A030313690), Guangdong Medical Scientific Research Foundation (no. A2018062), Guangdong Basic and Applied Basic Research Foundation (no. 2019A1515011928 and 2020A1515110061), and Science and Technology Program of Guangzhou (no. 201904010088).

Acknowledgements:

We thank all subjects and medical staff who generously contributed to this study.

Disclosure of Interests:

None declared

Three-dimensional bioprinting of artificial ovaries by an extrusion-based method using gelatin-methacryloyl bioink

PURPOSE

The aim of this study was to design and fabricate a three-dimensional (3D) printed artificial ovary.

METHODS

We first compared the printability of gelatin-methacryloyl (GelMA), alginate and GelMA-alginate bioinks, of which GelMA was selected for further investigation. The swelling properties, degradation kinetics and shape fidelity of GelMA scaffolds were characterized by equilibrium swelling/lyophilization, collagenase processing and micro-computed tomography evaluation. Commercial ovarian tumor cell lines (COV434, KGN, ID8) and primary culture ovarian somatic cells were utilized to perform cell-laden 3D printing, and the results were evaluated by live/dead assays and TUNEL detection. Murine ovarian follicles were seeded in the ovarian scaffold and their diameters were recorded every day. Finally, in vitro maturation was performed, and the ovulated oocytes were collected and observed.

RESULTS

Our results indicated that GelMA was suitable for 3D printing fabrication. Its scaffolds performed well in terms of hygroscopicity, degradation kinetics and shape fidelity. The viability of ovarian somatic cells was lower than that of commercial cell lines, suggesting that extrusion-based 3D culture fabrication is not suitable for primary ovarian cells. Nevertheless, the GelMA-based 3D printing system provided an appropriate microenvironment for ovarian follicles, which successfully grew and ovulated in the scaffolds. Metaphase II oocytes were also observed after in vitro maturation.

CONCLUSIONS

The GelMA-based 3D printing culture system is a viable alternative option for follicular growth, development and transfer. Accordingly, it shows promise for clinical application in the treatment of female endocrine and reproductive conditions.

Intrinsic Spin Susceptibility and Pseudogaplike Behavior in Infinite-Layer LaNiO_{2}

The recent discovery of superconductivity in doped infinite-layer nickelates has stimulated intensive interest, especially for similarities and differences compared to that in cuprate superconductors. In contrast to cuprates, although earlier magnetization measurement reveals a Curie-Weiss-like behavior in undoped infinite-layer nickelates, there is no magnetic ordering observed by elastic neutron scattering down to liquid helium temperature. Until now, the nature of the magnetic ground state in undoped infinite-layer nickelates was still elusive. Here, we perform a nuclear magnetic resonance (NMR) experiment through ^{139}La nuclei to study the intrinsic spin susceptibility of infinite-layer LaNiO_{2}. First, the signature for magnetic ordering or freezing is absent in the ^{139}La NMR spectrum down to 0.24 K, which unambiguously confirms a paramagnetic ground state in LaNiO_{2}. Second, a pseudogaplike behavior instead of Curie-Weiss-like behavior is observed in both the temperature-dependent Knight shift and nuclear spin-lattice relaxation rate (1/T_{1}), which is widely observed in both underdoped cuprates and iron-based superconductors. Furthermore, the scaling behavior between the Knight shift and 1/T_{1}T has also been discussed. Finally, the present results imply a considerable exchange interaction in infinite-layer nickelates, which sets a strong constraint for the proposed theoretical models.

Detection of CTCs and CSCs in the staging and metastasis of non-small cell lung cancer based on microfluidic chip and the diagnostic significance

OBJECTIVE

Dynamic monitoring of CTCs/CSCs can assist in the diagnosis and prognosis of tumors. This study explores the diagnostic significance of microfluidic chip technology in the detection of CTCs/CSCs in clinical staging and metastasis of patients with non-small cell lung cancer (NSCLC). That lays a solid foundation for the use of microfluidic chips to monitor CTCs/CSCs for the stage and metastasis of patients with non-small cell lung cancer.

PATIENTS AND METHODS

This study collected 80 patients with lung cancer from October 2017 to October 2018. Meanwhile, 30 healthy people and 30 patients with benign lung diseases were selected during the same period as the control group 1 and the control group 2, respectively. CellSearch (Huntington Valley, PA, USA) and microfluidic chip were used to detect CTCs, the sensitivities were recorded. ELISA methods were used to detect the concentrations of tumor markers VEGF-C, CEA, and CA125 in serum, and their association with CTCs and CSCs was analyzed. In addition, after 3 months, we followed up 40 patients with lung cancer, recorded their prognosis, and extracted peripheral blood to detect changes in their CTCs and CSCs. The CellSearch (Huntington Valley, PA, USA) system and the microfluidic chip system were used to detect the CTCs in patients with lung cancer, and the sensitivity and specificity of the patients were analyzed. The changes in CTCs and CSCs in the peripheral blood of the patient were recorded.

RESULTS

It can be seen that the positive rate of CTCs and CSCs is not significantly correlated with the patients' age, gender, pathological type (adenocarcinoma, squamous cell carcinoma), etc. They are significantly correlated with clinical stage (I + II and III + IV) and metastasis (metastasis and non-metastasis) (p<0.01). Then, we divided the patients into groups for testing, and analyzed the association between different groups of patients and CTCs and CSCs. Compared with control group 1 and control group 2, the positive rates of CTCs and CSCs in lung cancer metastasis group and non-metastasis group were significantly different (p<0.05). Compared with the control group 1 and control group 2, the positive rates of CTCs and CSCs in stage I + II and III + IV of lung cancer were significantly different (p<0.05). The positive rate was significantly higher in the cancer metastasis group (p<0.05). The concentrations of tumor markers VEGF-C, CEA, CA125 in the serum of patients were consistent with CTCs-negative and CTC-positive lung cancer, with significant differences (p<0.05). CSCs negative and CSCs positive patients have similar results. Subsequently, we analyzed the sensitivity and specificity of CSCs, CTCs, and tumor markers for the diagnosis of NSCLC. The results showed that the sensitivity of CSCs and CTCs to diagnose patients was significantly higher than that of tumor markers.

CONCLUSIONS

This study shows that our microfluidic chip device can exhibit relatively good performance and can better detect CTCs and CSCs. Monitoring CTCs and CSCs of patients can provide a basis for judging the stage and metastasis of patients.

Highly Degenerate Ground States in a Frustrated Antiferromagnetic Kagome Lattice in a Two-Dimensional Metal-Organic Framework

Realization of the Kagome antiferromagnetic (KAF) lattice is of high interest because the geometric frustration in the Kagome lattice is expected to give rise to highly degenerated ground states that may host exotic phases such as quantum spin liquid. Here we demonstrate the design and synthesis of a single-layer two-dimensional metal-organic framework (2D-MOF) containing a Kagome lattice of Fe(II) ions assembled on a Au(111) surface. First-principles calculations reveal that the Fe(II) ions are at a high spin state of S = 2 and are coupled antiferromagnetically with nearest-neighboring exchange J₁ = 5.8 meV. The ground state comprises various degenerated spin configurations including the well-known q = 0 and q = √3 × √3 phases. Remarkably, we observe a spin excitation at 6 meV using tunneling spectroscopy. This work points out a feasible route toward realizing spin ¹/₂ KAF, a candidate quantum spin liquid system, by replacing Fe(II) by Cu(II) in the same structure.

Surfactant-Enhanced Spontaneous Emulsification Near the Crude Oil-Water Interface

Spontaneous emulsification near the oil-water interface and destabilization of water-in-oil emulsions in the bulk oil phase may affect the efficiency of improved oil recovery. In this study, we investigate the effect of a demulsifier surfactant on spontaneous emulsification near the oil-aqueous phase interface and in the bulk oil phase through imaging. The results show that pronounced spontaneous emulsions may form near the oil-aqueous phase interfaces. The mechanism of diffusion and stranding is believed to dominate spontaneous emulsification. A demulsifier surfactant, which has been used for demulsification of water-in-oil emulsions in the bulk oil phase, is found to enhance spontaneous emulsification near the oil-water interface. The diffusive flux of water through the interface can be enhanced if the demulsifier is added into the aqueous phase, in which the demulsifier may act as a carrier. It can generate a region of local supersaturation combined with hydrated asphaltenes and result in faster and stronger spontaneous emulsification. We also investigate the effect of a viscosifier polymer on emulsion formation. The polymer is used to improve sweep efficiency in oil displacement. In this work, we show that it can inhibit emulsification in the bulk oil phase, but its effect on spontaneous emulsification near the interface is not pronounced.

Quantitative comparative phosphoproteomic analysis of the effects of colostrum and milk feeding on liver tissue of neonatal calves

Posttranslational modifications, mostly phosphorylation, are critical for protein structure and function. However, the association between liver phosphoproteins in neonatal calves and colostrum intake is not well understood. In this study, we examined the liver phosphoproteome profile in neonatal calves after receiving colostrum or milk. Liver tissue samples were collected from control calves (CON, n = 3) 2 h after birth and from calves that received colostrum (CG, n = 3) or milk (MG, n = 3) 24 h after birth. Hepatic phosphoprotein expression profiles were analyzed using quantitative proteomics based on the liquid chromatography-tandem mass spectrometry method. In total, 1,587 phosphorylated sites were identified in 1,011 liver proteins. The most abundant phosphorylation site AA was serine (87.5%), followed by threonine (11.9%) and tyrosine (0.5%). Among the 1,011 phosphoproteins, 219, 453, and 26 displayed differential expression in the CG versus MG, CG versus CON, and MG versus CON comparisons, respectively. Differentially expressed phosphoproteins in the CG-MG comparison included 3-phosphoinositide-dependent protein kinase 1, glucose transporter member 4, protein kinase N2, and vinculin, which were mainly involved in the glycogen metabolic process, transport, growth and development, and cell adhesion process, according to Gene Ontology analysis. Pathway analysis indicated their enrichment in the insulin signaling pathway, spliceosome, and adherens junction. The CG-CON comparison identified differentially expressed phosphoproteins and their target genes that were largely involved in the cellular process, macromolecule metabolic process, developmental process, and transport. Pathway analysis indicated their association with endocytosis, mechanistic target of rapamycin, AMP-activated protein kinase, and insulin signaling pathways. These data demonstrate that changes in the phosphoproteins of liver tissues may play an important role in energy metabolism and immune response in the calves that received colostrum. These results provide novel insights into the crucial roles of protein phosphorylation during the early life of newborn calves.

Distance to water source in early childhood affects growth: a cohort study

OBJECTIVES

Approximately 165 million children aged <5 years are at risk of low height-for-age. This study explored whether water quality and distance to water source affected short- and long-term growth, and the critical time windows of such effects.

STUDY DESIGN

This study used data from the China Health and Nutrition Survey (CHNS), which was a cohort study performed in 15 Chinese provinces.

METHODS

Data from the CHNS between 1989 and 2011 were examined. Three cohorts of children who were enrolled at 0-2 years of age in 1989, 1993, and 2000 provided sufficient data for this study. Child height was measured by physicians, and household water supply, including the water quality (safe or unsafe) and distance to the source (in-yard or out-yard), was assessed using a questionnaire when the children were 0-2, 4-6, and 11-13 years of age. Multiple regressions were performed to analyse the associations between water quality and distance to the source at various ages, and height at that age and older ages, with and without adjusting for the household water supply at previous ages. Multiple informant models were created using a generalised estimating equation and these were used to assess whether the exposure coefficients were equal across the three age periods.

RESULTS

A total of 1192 children were included. Water quality was not significantly associated with height over the three age periods. An out-yard water source at the age of 0-2 years was not associated with child height at that age, but it was inversely associated with child height at ages 4-6 and 11-13 years (β = -1.605, 95% confidence interval [CI]: -2.490 to -0.720, and β = -2.817, 95% CI: -4.411 to -1.224, respectively), after adjusting for sociodemographic and economic covariates and baseline child height. Distance to the water source at age 4-6 and 11-13 years was not significantly associated with height. However, significant differences were observed in the associations between distance to water source across the three age periods and height at age 4-6 and 11-13 years (p_int = 0.064 and 0.069, respectively).

CONCLUSIONS

Distance to the water source in early, but not later, childhood exerted a long-term effect on child height. When the water quality is good, efforts should be made to shorten the distance to the source to improve child health and growth.

Drug utilization of paliperidone in adolescent schizophrenia patients: A retrospective cohort study in China

Introduction

In China, the indications of paliperidone extended in schizophrenia adolescents (12-17 years) was approved by National Medical Products Administration (NMPA) in 2017. But, the utilization of paliperidone in this group needs to be further investigated.

Objectives

To assess paliperidone utilization in schizophrenia adolescents.

Methods

The study employed the electronic medical records (EMRs) database from a psychiatry specialized hospital (PH) and a general hospital (GH), respectively. General information, including birth date, gender, visit date, diagnosis (inpatient and outpatient) with ICD-10 coding, drug characterize, prescription date and dosage, was de-identified and standardized for analysis. Schizophrenia adolescents (ICD-10: F20.x) received at least one prescription of paliperidone between 2018 and 2019 were included in this study. Index date was defined as the date of first identified paliperidone prescription. The patients were followed up until the end of 2019 with the last record, or upon reaching 18 years. The database was analyzed based on days of supply, administration frequency, and daily dose.

Results

Overall, 112 and 117 eligible patients were included in the present study from PH and GH, respectively. The median drug supply was 179.0 days and 44.0 days, respectively, during which median number of prescriptions patients received was 6.0 and 3.0. Paliperidone was mostly initiated alone (57.1% and 88.9%) with frequency of once daily (97.3% and 88.9%), and the median of average daily dose during follow-up was 5.7 mg/day and 6.0 mg/day, respectively.

Conclusions

The duration of paliperidone usage was very different in two hospitals, but the dosages in both hospitals were generally agreed with prescribing information.

Dosage of antipsychotics in China routine practice

Introduction

The antipsychotic dosage of Chinese schizophrenia patients has rarely been studied, although nonstandard dosage has impact on prognosis.

Objectives

To describe the dosage of antipsychotics in China routine practice.

Methods

This was a retrospective cohort study using de-identified data from a Chinese mental health hospital. The included patients were adults (≥18 years) with at least one diagnosis of schizophrenia (ICD-10: F20) and one prescription of any antipsychotic between 2014 and 2019. Date of first identified antipsychotic prescription was defined as index date, patients were followed up until last prescription of antipsychotics, end of 2019, or discontinuation (>60 days without antipsychotic prescription), whichever was earliest. Dosage was summarized using defined daily dose (DDD), calculated by cumulative average daily dose (CAD) with a unit of DDDs/day, i.e., total DDDs of all antipsychotics in follow-up period divided by total days of follow-up. CAD was categorized into low (<0.5 DDDs/day), moderate (0.5-1.5 DDDs/day), and high (>1.5 DDDs/day) groups.

Results

13554 patients were included with an average follow-up of 269.9 days. Median CAD was 0.8 DDDs/day (IQR=0.5-1.3), patients with hospitalization during follow-up and used multiple antipsychotics at the same time had larger median CAD, 1.0 DDDs/day and 1.2 DDDs/days, respectively. There were 3245 (23.9%), 7627 (56.3%), and 2682 (19.8%) patients in low, moderate, and high groups, respectively. The median CAD of high dosage group was 2.5 DDDs/day (IQR=1.9-10.5).

Conclusions

CAD of most Chinese schizophrenia patients was low or moderate. Association between CAD and hospitalization and multiple concurrent antipsychotics merit further research.

[Comparative study on metagenomics of esophageal flora in elderly and middle-aged esophageal squamous cell carcinoma patients]

Objective: To explore the flora characteristics and differences of esophageal tissues between elderly esophageal squamous cell carcinoma (ESCC) patients and young and middle-aged ESCC patients, so as to assist in studying the potential biomarkers of elderly ESCC patients. Methods: In this study, a retrospective study was adopted. 72 ESCC patients diagnosed in Taihe Hospital, Shiyan City, Hubei Province from July 2018 to July 2019 were selected, including 49 patients in the elderly group (≥ 60 years old, 40 males and 9 females), 23 patients in the young and middle-aged group (<60 years old, 21 males and 2 females). In the same period, 20 healthy persons without abnormal gastroscopy in endoscopy center were selected as the control group (aged 35-78 years old, median age 57 years old, 16 males and 4 females). The genomic DNA was extracted from the affected esophageal tissues of patients with ESCC and the middle esophageal samples of the control group. The V4 hypervariable region of bacterial 16SrRNA gene sequence was amplified. Illumina HiSeq sequencing technology was adopted. The flora characteristics of elderly, young and middle-aged ESCC patients was compared and analyzed. QIIME and Rstudio software were used to analyze the sequence data, and nonparametric Kruskal-Wallis test or Wilcoxon rank sum test were used for statistical methods. Results: Shannon index [5.17 (4.53, 5.95) vs. 4.79 (3.74, 5.97)], Simpson index [0.94 (0.91, 0.96) vs. 0.92 (0.83, 0.96)] and Chao1 index [343.55 (259.76, 570.59) vs. 329.16 (268.88, 648.00)] were similar in flora of two groups, and there was no significant difference (Z=-0.791, -1.057, -0.380, all P>0.05). There was no significant difference in β-diversity between the elderly group and the young and middle-aged group (PC1=19.14%, PC2=6.95%, P_PC1=0.67, P_PC2=0.42). At the phyla level, the top 5 phyla in abundance were as follows: Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria in the young and middle-aged group, while the top 5 phyla in abundance were as follows: Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria and Actinobacteria in the elderly group; the significant difference between the two groups was Fusobacteria (Q=0.596, P<0.05). At the genus level, the top 5 genera in the young and middle-aged group in abundance were as follows: Prevotella, Bacteroides, Streptococcus, Selenomonas and Veillonella. In the elderly group, Prevotella, Bacteroides, Streptococcus, Selenomonas and Haemophilus were the top 5 in abundance, and there were significant difference in Fusobacterium between the two groups (Q=0.938, P<0.05). PICRUSt function prediction showed that the abundance of Aminoacyl.tRNA.biosynthesis, Nucleotide.excision.repair, RNA.polymerase, Ribosome, Clavulanic.acid.biosynthesis, Photosynthesis and Photosynthesis. proteins in the elderly group were lower than those in the young and middle-aged group (all Q=0.734, P<0.05). Conclusion: There is no significant difference in α-diversity and β-diversity between elderly ESCC patients and young and middle-aged patients, but the abundance of Fusobacterium flora increased.

Perfluorocarbon Protects against Lipopolysaccharide-Induced Apoptosis of Endothelial Cells in Pulmonary Microvessels

This study was aimed to explore the effect and mechanisms of action of perfluorocarbon on LPS-induced apoptosis of pulmonary microvascular endothelial cells (PMVEC) isolated from Sprague-Dawley rats. Apoptosis rates were assessed by flow cytometry. Ultrastructural characteristics of PMVEC were evaluated by transmission electron microscopy. The protein expression of cleaved caspase-3 was measured using Western blotting. LPS significantly increased the level of apoptosis, induced the appearance of ultrastructural changes typical of apoptosis, up-regulated the expression of active caspase-3 protein. These effects of LPS were attenuated by co-administration of perfluorocarbon. These results suggest that perfluorocarbon can attenuate LPS-induced apoptosis of PMVEC by inhibiting TLR-4 signaling and caspase-3 activation.

On-surface preparation of coordinated lanthanide-transition-metal clusters

The study of lanthanide (Ln)-transition-metal (TM) heterometallic clusters which play key roles in various high-tech applications is a rapid growing field of research. Despite the achievement of numerous Ln-TM cluster compounds comprising one Ln atom, the synthesis of Ln-TM clusters containing multiple Ln atoms remains challenging. Here, we present the preparation and self-assembly of a series of Au-bridged heterometallic clusters containing multiple cerium (Ce) atoms via on-surface coordination. By employing different pyridine and nitrile ligands, the ordered coordination assemblies of clusters containing 2, 3 and 4 Ce atoms bridged by Au adatoms are achieved on Au(111) and Au(100), as revealed by scanning tunneling microscopy. Density functional theory calculations uncover the indispensable role of the bridging Au adatoms in constructing the multi-Ce-containing clusters by connecting the Ce atoms via unsupported Ce-Au bonds. These findings demonstrate on-surface coordination as an efficient strategy for preparation and organization of the multi-Ln-containing heterometallic clusters.

Influence of physicochemical properties and starch fine structure on the eating quality of hybrid rice with similar apparent amylose content

In this study, we compared the physicochemical properties and starch structures of hybrid rice varieties with similar apparent amylose content but different taste values. In addition to the apparent amylose content, gel permeation chromatography analysis showed that the higher proportions of amylopectin short chains and relatively lower proportions of amylopectin long chains, which could lead to higher peak viscosity and breakdown value, as well as a softer and stickier texture of cooked rice, were the key factors in determining the eating quality of hybrid rice. High-performance anion-exchange chromatography analyses showed that the proportion of amylopectin short chains (degree of polymerization 6-10) and intermediate chains (degree of polymerization 13-24), which might affect the gelatinisation enthalpy and crystallinity, also contributed greatly to the eating quality of hybrid rice. Moreover, this study indicated that a greater diversity of forms and sizes of starch granules might influence the eating quality of hybrid rice.