Long-term in vivo chimeric cells tracking in non-human primate

Non-human primates (NHPs) are increasingly used in preclinical trials to test the safety and efficacy of biotechnology therapies. Nonetheless, given the ethical issues and costs associated with this model, it would be highly advantageous to use NHP cellular models in clinical studies. However, developing and maintaining the naïve state of primate pluripotent stem cells (PSCs) remains difficult as does in vivo detection of PSCs, thus limiting biotechnology application in the cynomolgus monkey. Here, we report a chemically defined, xeno-free culture system for culturing and deriving monkey PSCs in vitro. The cells display global gene expression and genome-wide hypomethylation patterns distinct from monkey-primed cells. We also found expression of signaling pathways components that may increase the potential for chimera formation. Crucially for biomedical applications, we were also able to integrate bioluminescent reporter genes into monkey PSCs and track them in chimeric embryos in vivo and in vitro. The engineered cells retained embryonic and extra-embryonic developmental potential. Meanwhile, we generated a chimeric monkey carrying bioluminescent cells, which were able to track chimeric cells for more than 2 years in living animals. Our study could have broad utility in primate stem cell engineering and in utilizing chimeric monkey models for clinical studies.

Long-Chain Bio-Based Nylon 514 Salt: Crystal Structure, Phase Transformation, and Polymerization

Nylon 514 is one of the new long-chain bio-based nylon materials; its raw material, 1,5-pentanediamine (PDA), is prepared by biological techniques, using biomass as the raw material. The high-performance monomer of nylon 514, 1,5-pentanediamine-tetradecanedioate (PDA-TDA) salt, was obtained through efficient crystallization methods. Here, two crystal forms of PDA-TDA, anhydrous and dihydrate, were identified and studied in this paper. From the characterization data, their crystal structures and thermal behaviors were investigated. Lattice energy was calculated to gain further insight into the relationship between thermal stability and crystal structures. The contribution of hydrogen bonds and other intermolecular interactions to the crystal structure stability have been quantified according to detailed Hirshfeld and IRI analyses. Additionally, the transformation mechanism of the anhydrate and dihydrate was established through a series of well-designed stability experiments, in which the temperature and water activity play a significant role in the structural stability of crystalline forms. Eventually, we obtained nylon 514 products with good thermal stability and low absorption using stable dihydrate powders as monomers. The properties of nylon 514 products prepared by different polymerization methods were also compared.

[Zellweger syndrome caused by PEX6 gene variation in 2 cases and literature review]

Objective: To summarize the clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation. Methods: This was a case series research. Clinical date and genetic results of 2 neonatal cases of Zellweger syndrome caused by PEX6 gene variation in Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology and Affiliated Hospital of Guangdong Medical University from July 2021 to July 2022 were retrospectively collected and analyzed. Literature up to August 2023 was searched from electronic databases of China National Knowledge Infrastructure (CNKI), Wanfang Data and PubMed with the combined keywords of "Zellweger syndrome" "Zellweger spectrum disorder", and "PEX6 gene" both in Chinese and English. The main clinical features and genetic characteristics of Zellweger spectrum disorder caused by PEX6 gene variation were summarized. Results: The 2 male neonates both developed clinical manifestations as dyspnea, hypotonia, feeding difficulties, enlarged fontanelle, and high palatine arch after birth. Biochemical parameters indicated elevated bile acids, and the cranial ultrasound showed the enlarged bilateral ventricles and subependymal cyst in both 2 neonates. Zellweger syndrome was confirmed by whole exome sequencing, and the results revealed PEX6 gene variation in the 2 neonates, including compound heterozygous variants c.315G>A and c.2095-3T>G, and homozygous variant c.506_507del. Case 1 was hospitalized for 5 days, and case 2 for 32 days; they both died shortly after being discharged (the specific time is unknown). Literature review found 26 patients, including 2 neonates in this study, with Zellweger spectrum disorder caused by PEX6 gene defect reported in 1 Chinese article and 11 English articles. Clinical features included hearing loss (19 cases), developmental delay (19 cases), vision impairment (19 cases), elevated very long chain fatty acids (17 cases), brain malformations (15 cases), hypotonia (12 cases), hepatic insufficiency (12 cases), distinctive facies (10 cases), and dental impairment (9 cases). Compound heterozygous variations dominated the variation types (15 cases), and the frameshift variations (16 cases) were the main pathogenic variations. Conclusions: Zellweger spectrum disorder should be considered when neonates show hypotonia, feeding difficulty, distinctive facial appearance, brain malformations and failure of hearing screening, or when older children show retinitis pigmentosa, sensorineural hearing loss, amelogenesis imperfecta and developmental delays. Detection of genetic variation in the PEX gene is crucial for definitive diagnosis.

Pharmacological activity and clinical progress of Triptolide and its derivatives LLDT-8, PG490-88Na, and Minnelide: a narrative review

Triptolide, a compound isolated from a Chinese medicinal herb, has potent antitumor, immunosuppressive, and anti-inflammatory properties. Due to its interesting structural features and diverse pharmacological activities, it has attracted great interest by the Society of Organic Chemistry and Pharmaceutical Chemistry. However, its clinical potential is greatly hampered by limited aqueous solubility and oral bioavailability, and multi-organ toxicity. In recent years, various derivatives of Triptolide have made varying degrees of progress in the treatment of inflammatory diseases, autoimmune diseases, and cancer. The most researched and potentially clinically valuable of them were (5R)-5-hydroxytriptolide (LLDT-8), PG490-88Na (F6008), and Minnelide. In this review, we provide an overview of the advancements made in triptolide and several of its derivatives' biological activity, mechanisms of action, and clinical development. We also summarized some prospects for the future development of triptolide and its derivatives. It is hoped to contribute to a better understanding of the progress in this field, make constructive suggestions for further studies of Triptolide, and provide a theoretical reference for the rational development of new drugs.

A Remineralizing and Antibacterial Coating for Arresting Caries

Dental caries is a dynamic disease induced by the unbalance between demineralization of dental hard tissues caused by biofilm and remineralization of them; however, although various effective remineralization methods have been well documented, it is a challenge to reestablish the balance by enhancing remineralization alone while ignoring the antibacterial therapy. Therefore, the integration of remineralizing and antibacterial technologies offers a promising strategy to halt natural caries progression in clinical practice. Here, the conception of interrupting dental caries (IDC) was proposed based on the development of dual-functional coating with remineralizing and antibacterial properties. In this study, bovine serum albumin (BSA) loaded octenidine (OCT) successfully to form a BSA-OCT composite. Subsequently, through fast amyloid-like aggregation, the phase-transited BSA-OCT (PTB-OCT) coating can be covered on teeth, resin composite, or sealant surfaces in 30 min by a simple smearing process. The PTB-OCT coating showed satisfactory effects in promoting the remineralization of demineralized enamel and dentin in vitro. Moreover, this coating also exerted significant acid-resistance stability and anti-biofilm properties. Equally importantly, this coating exhibited promising abilities in reducing the microleakage between the tooth and resin composite in vitro and preventing primary and secondary caries in vivo. In conclusion, this novel dual-functional PTB-OCT coating could reestablish the balance between demineralization and remineralization in the process of caries, thereby potentially preventing or arresting caries.

The Incidence and Prognosis Value of Perineural Invasion in Rectal Carcinoma: From Meta-Analyses and Real-World Clinical Pathological Features

AIMS

Perineural invasion (PNI) is a special type of metastasis of several cancers and has been reported as being a factor for poor prognosis in colorectal carcinoma. However, investigations of PNI in only rectal cancer and a comprehensive analysis combining meta-analyses with real-world case studies remain lacking.

MATERIALS AND METHODS

First, articles from 2000 to 2020 concerning the relationship between PNI and rectal cancer prognoses and clinical features were meta-analysed. Subsequently, we carried out a retrospective analysis of 312 rectal cancer cases that underwent radical surgery in the real world. The incidence of PNI and the relationship between PNI and prognosis, as well as clinicopathological factors, were investigated.

RESULTS

The incidence of PNI was 23.09% and 33.01% in the meta-analysis and clinical cases, respectively. PNI occurred as early as stage I (2.94%). Moreover, neoadjuvant therapy significantly reduced the PNI-positive rate (20.34% versus 26.54%). Both meta-analysis and real-world clinical case studies suggested that PNI-positive patients had poorer prognoses than PNI-negative patients. We established an effective risk model consisting of T stage, differentiation and lymphovascular invasion to predict PNI in rectal cancer.

CONCLUSION

PNI is a poor prognostic factor for rectal cancer and could occur even in stage I. Additionally, neoadjuvant therapy could sufficiently reduce the PNI-positive rate. T stage, lymphovascular invasion and differentiation grade were independent risk factors for PNI and the risk model that included these factors could predict the probability of PNI.

Stereotactic Body Radiotherapy Combined with Sintilimab in Patients with Recurrent or Oligometastatic Hepatocellular Carcinoma: A Phase II Clinical Trial

PURPOSE/OBJECTIVE(S)

The anti-tumor activity and tolerability of stereotactic body radiotherapy (SBRT) and PD-1 inhibitors have been illustrated in retrospective studies, but the results vary across a broad range. This study aimed to assess the clinical efficacy of SBRT combined with sintilimab in patients with recurrent or oligometastatic hepatocellular carcinoma (HCC).

MATERIALS/METHODS

This trial involved patients with recurrent or oligometastatic HCC intravenously treated with SBRT plus sintilimab every 3 weeks for 12 months or until disease progression. The primary endpoint was progression-free survival (PFS).

RESULTS

Twenty-five patients were enrolled from August 14, 2019, to August 23, 2021. The median treatment duration was 10.2 months. SBRT was delivered at a median dose of 54 in six fractions. The median follow-up time was 21.9 months, and 32 targeted lesions among 25 patients were evaluated for treatment response according to the Response Evaluation Criteria in Solid Tumors version 1.1. The median PFS was 19.7 months, with PFS rates of 68% and 45.3% at 12 and 24 months, respectively. The median overall survival (OS) was not reached, with OS rates of 91.5% and 83.2% at 12 and 24 months, respectively. The 1- and 2-year local control rate were 100% and 90.9%, respectively. The confirmed objective response rate and disease control rate was 96%, and 96%, respectively. Most adverse events were graded as 1 or 2, and grade 3 adverse events were observed in three patients.

CONCLUSION

SBRT plus sintilimab is an effective, well-tolerated treatment regimen for patients with recurrent or oligometastatic HCC.

[Clinical efficacy of local injection of platelet-rich plasma combined with double-layer artificial dermis in treating wounds with exposed tendon on extremity]

Objective: To investigate the clinical efficacy of local injection of platelet-rich plasma (PRP) combined with double-layer artificial dermis in treating wounds with exposed tendon on extremity. Methods: A retrospective observational study was conducted. From December 2017 to October 2022, 16 patients were admitted to Department of Orthopaedic Trauma of the Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, and 32 patients were admitted to Department of Burns and Plastic Surgery of Guiyang Steel Factory Staff Hospital. All the patients had wounds with exposed tendon on extremity caused by various reasons and met the inclusion criteria. There were 39 males and 9 females, aged 26 to 58 years. The patients were divided into PRP alone group, artificial dermis alone group, and PRP+artificial dermis group, with 16 patients in each group. The wounds were treated with autologous PRP, double-layer artificial dermis, or thei combination of autologous PRP and double-layer artificial dermis, followed by autologous split-thickness scalp grafting after good growth of granulation tissue. On the 7th day after the secondary surgery, the autograft survival was observed, and the survival rate was calculated. The wound healing time and length of hospital stay of patients were recorded. At 3 and 6 months after wound healing, the Vancouver scar scale (VSS) was used to score the pigmentation, height, vascularity, and pliability of scars, and the total score was calculated. Adverse reactions during the entire treatment process were recorded. Data were statistically analyzed with chi-square test, Fisher's exact probability test, one-way analysis of variance, least significant difference test, Kruskal-Wallis H test, Nemenyi test, and Bonferroni correction. Results: On the 7th day after the secondary surgery, there was no statistically significant difference in the autograft survival rate of patients among PRP alone group, artificial dermis alone group, and PRP+artificial dermis group (P>0.05). The wound healing time and length of hospital stay of patients in PRP+artificial dermis group were (20.1±3.0) and (24±4) d, respectively, which were significantly shorter than (24.4±5.5) and (30±8) d in PRP alone group (P<0.05) and (24.8±4.9) and (32±8) d in artificial dermis alone group (P<0.05). At 3 and 6 months after wound healing, the pliability scores of patients in PRP+artificial dermis group were significantly lower than those in PRP alone group (with Z values of 12.91 and 15.69, respectively, P<0.05) and artificial dermis alone group (with Z values of 12.50 and 12.91, respectively, P<0.05). There were no statistically significant differences in pigmentation, vascularity, height scores, and total score of scar of patients among the three groups (P>0.05). In artificial dermis alone group, one patient experienced partial liquefaction and detachment of the double-layer artificial dermis due to local infection of Staphylococcus epidermidis, which received wound dressing change, second artificial dermis transplantation, and subsequent treatment as before. No adverse reactions occurred in the remaining patients during the whole treatment process. Conclusions: Local injection of PRP combined with double-layer artificial dermis is effective in treating wounds with exposed tendon on extremity, which can not only significantly shorten wound healing time and length of hospital stay, but also improve scar pliability after wound healing to some extent in the long term. It is a clinically valuable treatment technique that is worth promoting and applying.

[Comparison of incubation periods of infections of Omicron variants BA.2 and BF.7 in Beijing]

Objective: To understand the incubation periods of infections of Omicron variants BA.2 and BF.7 in two COVID-19 epidemics and related factors in Beijing and provide basic parameters for the establishment of 2019-nCoV dynamic transmission model. Methods: The COVID-19 cases with specific exposure time and onset time in the Omicron variant BA.2 infection epidemic in April 2022 and in the Omicron variant BF.7 infection epidemic in October 2022 in Beijing were included in the analysis. The rank-sum test was conducted to estimate the differences in the incubation period between two types of infections. The incubation period distribution of the Omicron variant infection was fitted by using Weibull, Gamma and lognormal distributions. Multivariate analysis of variance was conducted to assess the effects of age, sex, variant type and vaccination status on the incubation periods. Results: A total of 64 cases of variant BA.2 infection and 58 cases of variant BF.7 infection were included. The M(Q1,Q3) of the incubation period was 3.00 (3.00, 4.00) days for BA.2 infection and 3.00 (2.00, 3.25) days for BF.7 infection. The lognormal distribution was the best fit. Multivariate analysis of variance showed that there were some differences in the incubation periods between two types of infections of Omicron variants, and the incubation period of variant BF.7 infection was shorter than that of variant BA.2 infection. Conclusion: Omicron variant BF.7 infection had shorter incubation period compared with Omicron variant BA.2 infection.

Solubility, Crystallization, and Characterization of Cytidine Sulfate

Cytidine is an important kind of nucleoside that can be applied to drug development and food industry. Cytidine sulfate is one of its popular forms, which is promising as a medicinal intermediate, especially in antiviral and antitumor drugs. Product refining is the key point of industrial development, and crystallization is a significant way of refining. In this work, the solubility of cytidine sulfate in pure water from 278.15 to 328.15 K and in water-ethanol binary solvents at 298.15 K was measured by the UV spectroscopic method. The solubility data were correlated with temperature and solvent composition using the modified Apelblat, van't Hoff, and CNIBS/R-K equations. On this basis, we investigated and compared three crystallization processes, and the coupling method was developed to prepare crystals with a large particle size, concentrated distribution, and high yield and packing density. In addition, the structure and stability of the products were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamic vapor sorption analysis. It was found that cytidine sulfate has only one crystal form in our research process, and the product of coupling crystallization is stable and favorable for industrial development.

Spatiotemporal proteomic atlas of multiple brain regions across early fetal to neonatal stages in cynomolgus monkey

Fetal stages are critical periods for brain development. However, the protein molecular signature and dynamics of the human brain remain unclear due to sampling difficulty and ethical limitations. Non-human primates present similar developmental and neuropathological features to humans. This study constructed a spatiotemporal proteomic atlas of cynomolgus macaque brain development from early fetal to neonatal stages. Here we showed that (1) the variability across stages was greater than that among brain regions, and comparisons of cerebellum vs. cerebrum and cortical vs. subcortical regions revealed region-specific dynamics across early fetal to neonatal stages; (2) fluctuations in abundance of proteins associated with neural disease suggest the risk of nervous disorder at early fetal stages; (3) cross-species analysis (human, monkey, and mouse) and comparison between proteomic and transcriptomic data reveal the proteomic specificity and genes with mRNA/protein discrepancy. This study provides insight into fetal brain development in primates.

[Clinical features and prognostic factors of elderly patients with mantle cell lymphoma]

Objective: To examine the clinical characteristics and prognostic factors of elderly patients with mantle cell lymphoma (MCL) and the impact of nutrition and underlying diseases on the prognosis of elderly patients with MCL. Methods: retrospectively analyzed 255 elderly patients with MCL from 11 medical centers, including Peking University Third Hospital between January 2000 and February 2021. We analyzed clinical data, such as age, gender, Mantle Cell Lymphoma International Prognostic Index score, and treatment options, and performed univariate and multivariate prognostic analysis. We performed a comprehensive geriatric assessment on elderly MCL patients with medical records that included retraceable underlying disease and albumin levels, and we investigated the impact of basic nutrition and underlying disorders on MCL prognosis in the elderly. Results: There were 255 senior individuals among the 795 MCL patients. Elderly MCL was more common in males (78.4%), with a median age of 69 yr (ages 65-88), and the majority (88.6%) were identified at a late stage. The 3-yr overall survival (OS) rate was 42.0%, with a 21.2% progression-free survival (PFS) rate. The overall response rate (ORR) was 77.3%, with a 33.3% total remission rate. Elderly patients were more likely than younger patients to have persistent underlying illnesses, such as hypertension. Multivariate analysis revealed that variables related with poor PFS included age of ≥80 (P=0.021), Ann Arbor stage Ⅲ-Ⅳ (P=0.003), high LDH level (P=0.003), involvement of bone marrow (P=0.014). Age of ≥80 (P=0.001) and a high LDH level (P=0.003) were risk factors for OS. The complete geriatric assessment revealed that renal deficiency was associated with poorer OS (P=0.047) . Conclusions: Elderly MCL patients had greater comorbidities. Age, LDH, renal function, bone marrow involvement, and Ann Arbor stage are all independent risk factors for MCL in the elderly.

[Efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation treatment for T lymphoblastic leukemia/lymphoma]

Objective: To analyze the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for treating T lymphoblastic leukemia/lymphoma (T-ALL/LBL) . Methods: This study retrospectively evaluated 119 adolescent and adult patients with T-ALL/LBL from January 2006 to January 2020 at Peking University Third Hospital and Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences. Patients were divided into chemotherapy-only, chemotherapy followed by allo-HSCT, and chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) groups according to the consolidation regimen, and the 5-year overall survival (OS) and progression-free survival (PFS) rates of each group were compared. Results: Among 113 patients with effective follow-up, 96 (84.9%) patients achieved overall response (ORR), with 79 (69.9%) having complete response (CR) and 17 (15.0%) having partial response (PR), until July 2022. The analysis of the 96 ORR population revealed that patients without transplantation demonstrated poorer outcomes compared with the allo-HSCT group (5-year OS: 11.4% vs 55.6%, P=0.001; 5-year PFS: 8.9% vs 54.2%, P<0.001). No difference was found in 5-year OS and 5-year PFS between the allo-HSCT and auto-HSCT groups (P=0.271, P=0.197). The same results were achieved in the CR population. Allo-HSCT got better 5-year OS (37.5% vs 0) for the 17 PR cases (P=0.064). Different donor sources did not affect 5-year OS, with sibling of 61.1% vs hap-haploidentical of 63.6% vs unrelated donor of 50.0% (P>0.05). No significant difference was found in the treatment response in the early T-cell precursor acute lymphoblastic leukemia/lymphoma (ETP) and non-ETP populations. The ETP group demonstrated lower 5-year OS compared with the non-ETP group in the chemotherapy alone group (0 vs 12.6%, P=0.045), whereas no significant difference was found between the ETP and non-ETP groups in the allo-HSCT group (75.0% vs 62.9%, P=0.852). Multivariate analysis revealed that high serum lactate dehydrogenase level, without transplantation, and no CR after chemotherapy induction were independently associated with inferior outcomes (P<0.05) . Conclusion: Allo-HSCT could be an effective consolidation therapy for adult and adolescent patients with T-ALL/LBL. Different donor sources did not affect survival. Allo-HSCT may overcome the adverse influence of ETP-ALL/LBL on OS.

[A preliminary study on the tear matrix metalloproteinase 9 point-of-care assay using a domestic kit]

Objective: To compare the point-of-care assays for tear matrix metalloproteinase 9 (MMP-9) using domestic and InflammaDry kits, and to evaluate the feasibility of diagnosing dry eye with the domestic kit. Methods: It was a cross-sectional study. Thirty dry eye patients and 30 age-and sex-matched normal volunteers were continuously enrolled in this cross-sectional study from June 2022 to July 2022. Both domestic and InflammaDry kits were used to detect the tear MMP-9 levels. The positive rates were recorded for qualitative analysis, and the gray ratios of bands (the gray value of detection bands to that of control bands) were collected for quantitative analysis. The correlations of MMP-9 levels with age, ocular surface disease index, fluorescence tear break-up time, tear meniscus height, Schirmer's Ⅰ test score, corneal fluorescein staining score, and meibomian gland dropout were analyzed. The Mann-Whitney U test, paired Chi-square test, Kappa test, and Spearman's correlation coefficient were used for statistical analysis. Results: There were 14 males and 16 females (30 eyes) in the control group, and their age was (39.37±19.55) years. In the dry eye group, 11 males and 19 females (30 eyes), aged (46.87±17.85) years, had moderate to severe dry eye. The positive rates of MMP-9 in tear fluid were significantly different between dry eye patients (InflammaDry: 86.67%; domestic kit: 70.00%) and controls (InflammaDry: 16.67%, P<0.001; domestic kit: 6.67%, P<0.001). Although the sensitivity of the domestic kit was lower than that of the InflammaDry kit (70.0% vs. 86.7%, P=0.001), the specificity was higher (93.3% vs. 83.3%, P=0.001). In dry eye patients, the positive coincidence rate was 80.7% (21/26), the negative coincidence rate was 100% (4/4), and the total coincidence rate was 83.3% (25/30), with no significant difference between the two kits (McNemar test: χ²=3.20, P>0.05), and the results of both kits were consistent (Kappa=0.53, P=0.001). The Spearman's correlation coefficient showed the gray ratios using both kits were positively correlated with the corneal fluorescein staining score (InflammaDry: ρ=0.48, P<0.05; domestic kit: ρ=0.52, P=0.003). Conclusion: The performances of the domestic and InflammaDry kits are consistent in the point-of-care assay for tear MMP-9, and the domestic kit has lower sensitivity but higher specificity.

Biofilm-Based Biocatalysis for Galactooligosaccharides Production by the Surface Display of β-Galactosidase in Pichia pastoris

Galactooligosaccharides (GOS) are one of the most important functional oligosaccharide prebiotics. The surface display of enzymes was considered one of the most excellent strategies to obtain these products. However, a rough industrial environment would affect the biocatalytic process. The catalytic process could be efficiently improved using biofilm-based fermentation with high resistance and activity. Therefore, the combination of the surface display of β-galactosidase and biofilm formation in Pichia pastoris was constructed. The results showed that the catalytic conversion rate of GOS was up to 50.3% with the maximum enzyme activity of 5125 U/g by screening the anchorin, and the number of the continuous catalysis batches was up to 23 times. Thus, surface display based on biofilm-immobilized fermentation integrated catalysis and growth was a co-culture system, such that a dynamic equilibrium in the consolidated integrative process was achieved. This study provides the basis for developing biofilm-based surface display methods in P. pastoris during biochemical production processes.

[Latent period and incubation period with associated factors of COVID-19 caused by Omicron variant]

Objective: To estimate the latent period and incubation period of Omicron variant infections and analyze associated factors. Methods: From January 1 to June 30, 2022, 467 infected persons and 335 confirmed cases in five local Omicron variant outbreaks in China were selected as the study subjects. The latent period and incubation period were estimated by using log-normal distribution and gamma distribution models, and the associated factors were analyzed by using the accelerated failure time model (AFT). Results: The median (Q₁, Q₃) age of 467 Omicron infections including 253 males (54.18%) was 26 (20, 39) years old. There were 132 asymptomatic infections (28.27%) and 335 (71.73%) symptomatic infections. The mean latent period of 467 Omicron infections was 2.65 (95%CI: 2.53-2.78) days, and 98% of infections were positive for nucleic acid detection within 6.37 (95%CI: 5.86-6.82) days after infection. The mean incubation period of 335 symptomatic infections was 3.40 (95%CI: 3.25-3.57) days, and 97% of them developed clinical symptoms within 6.80 (95%CI: 6.34-7.22) days after infection. The results of the AFT model analysis showed that compared with the group aged 18~49 years old, the latent period [exp(β)=1.36 (95%CI: 1.16-1.60), P<0.001] and incubation period [exp(β)=1.24 (95%CI: 1.07-1.45), P=0.006] of infections aged 0~17 year old were also prolonged. The latent period [exp(β)=1.38 (95%CI: 1.17-1.63), P<0.001] and the incubation period [exp(β)=1.26 (95%CI: 1.06-1.48), P=0.007] of infections aged 50 years old and above were also prolonged. Conclusion: The latent period and incubation period of most Omicron infections are within 7 days, and age may be the influencing factor of the latent period and incubation period.

[Chemical reprogramming of human embryonic fibroblasts into neural progenitor cells in vitro]

OBJECTIVE

To establish a protocol for reprogramming human embryonic fibroblasts (HEFs) into chemically induced neural progenitor cells (ciNPCs).

METHODS

In the two-staged reprogramming of HEFs, the intermediate compact cell colonies were first chemically induced in KSR medium containing small-molecule compounds (VCR) for 15 days in normoxia, followed by the lineage-specific induction stage, in which the compact cell colonies were digested with 0.25% trypsin and the cells were cultured in low adhesion plates. After formation of a large number of free-floating neurospheres 2 days later, the ciNPCs were labeled with CM-DiI and transplanted into rat models of Parkinson's disease (PD)to observe the survival, migration and differentiation of the cells in PD brain.

RESULTS

After induction with VCR for 10 days under normoxic condition, compact cell colonies occurred in HEF cultures (approximately 40 colonies in each well containing 1×10⁵ HEFs), and most of the colonies expressed high levels of alkaline phosphatase. A large number of free-floating neurospheres formed 2 days after passage and were defined as P1 ciNPCs. These ciNPCs exhibited typical neurosphere-like structures and expressed NPC-specific markers (nestin, Sox2, and Pax6). Under neuronal or glial differentiation condition, the ciNPCs expressed the neuron-specific marker Tuj1 and the astrocyte-specific marker GFAP. These ciNPCs could differentiate into Tuj1⁺, GFAP⁺, TH⁺ and GABA⁺ cells 4 weeks after transplantation into the brain of PD rats.

CONCLUSION

HEFs can be directly reprogrammed into ciNPCs using smallmolecule compounds without the need of introducing exogenous genes. This success may provide a solution to the shortage of donor materials for neuroscience research and treatment of neurodegenerative diseases.

[Analysis on infection sources and transmission chains of three outbreaks caused by 2019-nCoV Omicron variant in Beijing, China]

Objective: To investigate the infection sources and the transmission chains of three outbreaks caused by 2019-nCoV Omicron variant possibly spread through cross-border logistics in Beijing. Methods: Epidemiological investigation and big data were used to identify the exposure points of the cases. Close contacts were traced from the exposure points, and the cases' and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: The Omicron variant causing 3 outbreaks in Beijing from January to April, 2022 belonged to BA.1, BA.1.1 and BA.2. The outbreaks lasted for 8, 12 and 8 days respectively, and 6, 42 and 32 cases infected with 2019-nCoV were reported respectively. International mail might be the infection source for 1 outbreak, and imported clothes might be the infection sources for another 2 outbreaks. The interval between the shipment start time of the imported goods and the infection time of the index case was 3-4 days. The mean incubation period (Q₁, Q₃) was 3 (2,4) days and the mean serial interval (Q₁, Q₃) was 3 (2,4)days. Conclusions: The 3 outbreaks highlighted the risk of infection by Omicron variant from international logistics-related imported goods at normal temperature. Omicron variant has stronger transmissibility, indicating that rapid epidemiological investigation and strict management are needed.

The effect of polymorphism on polymer properties: crystal structure, stability and polymerization of the short-chain bio-based nylon 52 monomer 1,5-pentanediamine oxalate

The compound 1,5-pentanediamine (PDA) is prepared by biological methods using biomass as raw material. The salt of 1,5-pentanediamine oxalate (PDA-OXA) was used directly as the monomer for the preparation of a new bio-based nylon 52 material. High-performance polymer materials require initial high-quality monomers, and crystallization is an essential approach to preparing such a monomer. In this work, three crystal forms of PDA-OXA, the anhydrate, dihydrate and trihydrate, were found and the single crystals of two hydrates were obtained. Their crystal structures were determined using single-crystal and powder X-ray diffraction. The thermal behaviors were characterized by thermodynamic analysis, and the lattice energy was calculated to further explore the relationship between the thermal stability and crystal structure. Detailed computational calculations, Hirshfeld analyses and lattice energy calculations were performed to quantify both the contribution of intra- and intermolecular interactions to the supramolecular assembly, as well as the influence on the stability of the structure. The structure-property relationship between the PDA-OXA crystal forms was established. Moreover, the phase transformation mechanism between the crystalline forms of PDA-OXA has been established, and the control strategy of specific crystal forms was developed from the water activity-temperature phase diagram and relevant thermodynamic data. Finally, the influence of the polymorphism of the monomer and the polymerization methods on the properties of the polymer was investigated. The nylon 52 product obtained showed good appearance, high hardness and thermal stability, the polymer made using the anhydrate as the monomer has better thermodynamic properties than that prepared from the dihydrate, indicating practical industrial application prospects.

Speciation, bioaccessibility and human health risk assessment of chromium in solid wastes from an ultra-low emission coal-fired power plant, China

Chromium (Cr) in solid wastes from ultra-low emission (ULE) coal-fired power plants (CFPPs) could engender adverse effects on environment and human health. Hence, solid waste samples containing bottom ash, fly ash, gypsum and sludge were collected from a typical ULE CFPP in China to study the distribution, speciation, bioaccessibility and human health risk of Cr. The results showed that Cr was depleted in gypsum, whereas significantly enriched in bottom ash, fly ash and sludge comparing with feed coal. The ratios of Cr(VI) to total Cr in solid wastes were relatively low, but the increase of flow fractions in Cr chemical binding forms implied the deterioration of environmental stability. Based on the in vitro simulated digestion methods of solubility bioavailability research consortium (SBRC) and physiologically based extraction test (PBET), the bioaccessibility of Cr in the gastric and intestinal phases reached the highest values in either gypsum or sludge. After incorporating bioaccessibility in human health risk assessment, the carcinogenic risk (CR) within acceptable limits of Cr in solid wastes to adults and children was concluded, with the non-carcinogenic hazard quotient (HQ) was all within the safety threshold. The Monte Carlo model was applied to evaluate the uncertainty analysis of human health risk assessment at 5% and 95% confidence interval, and the fitting results were consistent with the calculation results of the carcinogenic and non-carcinogenic risk for adults and children. This study is expected to provide insights for the integration of bioaccessibility into the health risk assessment of Cr in solid wastes from ULE CFPPs, thus is conducive to the disposal of solid wastes and human health protection.

[Impact of NLR on atrial fibrillation recurrence after radiofrequency ablation in atrial fibrillation patients combined with heart failure]

Objective: To investigate the predictive value of neutrophils-to-lymphocytes ratio (NLR) for atrial fibrillation recurrence after radiofrequency ablation in atrial fibrillation patients combined with heart failure. Methods: This is a retrospective cohort study. Patients with atrial fibrillation and heart failure who received radiofrequency ablation in the First Affiliated Hospital of Zhengzhou University from January 2019 to June 2020 were included. Patient were followed up in the outpatient clinic at 3, 6, 9 and 12 months after radiofrequency ablation and were divided into recurrent and non-recurrent groups according to the absence or presence of atrial fibrillation. Demographic data, echocardiographic indices and inflammation-related indices including NLR were collected and compared between the two groups. Spearman rank correlation was performed to analyze the correlation of NLR with atrial fibrillation recurrence after radiofrequency ablation. Multivariate logistic regression analysis was used to determine independent risk factors of atrial fibrillation recurrence after radiofrequency ablation. The receiver operating characteristic (ROC) curve was used to evaluate the value of NLR in predicting the atrial fibrillation recurrence after radiofrequency ablation. Results: A total of 883 patients were included, of which 460 (52.1%) were male, mean age was (64.4±10.7) years old. There were 246 patients (27.9%) in the recurrence group and 637 patients (72.1%) in the non-recurrence group. Compared with the non-recurrent group, the duration of atrial fibrillation, NLR, neutrophil count, N-terminal B-type natriuretic peptide precursor (NT-proBNP) and body mass index levels were significantly higher, while lymphocyte count was significantly lower in the recurrence group than in the non-recurrent group (all P<0.05). Spearman rank correlation analysis showed that NLR was positively correlated with the atrial fibrillation recurrence (r=0.333, P<0.05). Multivariate logistic regression analysis showed that NLR was an independent risk factor for atrial fibrillation recurrence after radiofrequency ablation in atrial fibrillation patients combined heart failure (OR=1.634, P<0.001). The ROC curve showed that the area under the curve (AUC) of NLR in predicting the recurrence of atrial fibrillation after radiofrequency ablation was 0.715 (95%CI: 0.668-0.762, P<0.001), with a sensitivity of 55.61% and a specificity of 84.54%. Conclusion: NLR is a useful predictor of atrial fibrillation recurrence after radiofrequency ablation in atrial fibrillation patients combined with heart failure.

[Landscape and metastases of the lymph nodes in prostatic anterior fat pad at radical prostatectomy]

Objectives: To examine the landscape and metastases of the lymph nodes in prostatic anterior fat pad (PAFP) at radical prostatectomy (RP), and to describe the clinical characteristic of the patients with lymph node metastases in PAFP. Methods: The clinical and pathological data of 287 prostate cancer patients underwent RP from December 2019 to August 2021 in Department of Urology, Sun Yat-sen University Cancer Center were collected and analyzed retrospectively. All patients were male, aging (66±7) years (range: 42 to 83 years). The preoperative prostate-specific antigen (PSA) (M(IQR)) were 16.00(29.64) μg/L (range: 0.01 to 99.90 μg/L). There were 244 patients with localized or locally advanced prostate cancer and 43 patients with metastatic prostate cancer. All PAFP were dissected at RP routinely and were sent for pathologic analysis respectively. The PAFP was dissected from the prostate apex caudally toward the bladder neck and dissection extended to the joint of the prostate and the endopelvic fascia bilaterally. All the specimen of PAFP were examined and reported by subspecialty pathologists of genitourinary tumors. Statistical analysis was performed by Student t test, Wilcoxon rank-sum test, χ² test or Fisher exact test. Results: There were 8.0% (23/287) patients with lymph nodes in PAFP, 3.8% (11/287) patients with PAFP lymph node metastases. Pathologically upstaged occurred in 1 patient due to the PAFP lymph node as the solitary metastatic lesion. Patients with lymph node metastases in PAFP presented higher preoperative PSA (M(IQR): 48.2(73.0) μg/L vs. 15.4(26.5) μg/L, Z=3.158, P=0.002), clinical T stage and N stage (Z=2.977, P=0.003; Z=2.780, P=0.005) and preoperative Gleason score (Z=2.205, P=0.027). Conclusions: Routine dissection of PAFP at RP and separately pathological analysis may allow more lymph nodes and lymph node metastases detection. More accurate pathological N stage may be acquired and consequently may improve the survival of patients by offering more appropriate adjuvant or salvage therapy.

Association of usual walking with mortality in oldest old adults aged 85 years and older: a nationwide senior cohort study

Background

Current guidelines recommend moderate to vigorous intensity physical activity (MVPA) for health benefit in adults. However, it is difficult to meet the recommended minimum MVPA in “oldest old” aged over 85. Although walking is simple and easy exercise for oldest old, research on the association between walking and mortality in oldest old are lacking.

Purpose

To investigate the association between walking and the risk of all-cause and cardiovascular mortality among older adults aged 85 years and older.

Methods

7047 participants aged 85 or older underwent the Korean National Health Screening Program, including self-administered questionnaire for physical activity. Reported frequency per week of walking for at least 30 minutes increment was used to classify hours of walking per week. We computed multivariable-adjusted hazard ratios for walking and mutually adjusted for MVPA in relation to all-cause and cardiovascular mortality.

Results

The proportions of participants who engaged in walking, moderate- and vigorous-intensity physical activity were 42.5% (2996/7047), 14.7% (1037/7047) and 11.0% (773/7047), respectively. Only 7.6% (538/7047) of participants met the guidelines recommended minimum MVPA. Compared to inactive individuals, those who walked at least 1 hour per week had lower all-cause (HR 0.60 [95% CI, 0.50–0.74]) and cardiovascular mortality risk (HR 0.61 [95% CI, 0.42–0.89]). Walking 1 hour per week was still significant associated with reduction of risk for all-cause (HR 0.50 [95% CI, 0.40–0.61]) and cardiovascular mortality (HR 0.46 [95% CI, 0.30–0.70]) among participants who reported only walking without any MVPA.

Conclusions

1 hour a week of walking might be of benefit for all-cause and cardiovascular mortality in aged over 85 years, even without MVPA. Promoting walking may be a way to help oldest old avoid inactivity and encourage an active lifestyle for all-cause and cardiovascular mortality risk reduction.

Funding Acknowledgement

Type of funding sources: None.

Polymorph control by designed ultrasound application strategy: The role of molecular self-assembly

Molecular self-assembly plays a vital role in the nucleation process and sometimes determines the nucleation outcomes. In this study, ultrasound technology was applied to control polymorph nucleation. For the first time, different ultrasonic application methods based on the nucleation mechanisms have been proposed. For PZA-water and DHB-toluene systems that the molecular self-assembly in solution resembles the synthon in crystal structure, ultrasound pretreatment strategy was conducted to break the original molecular interactions to alter the nucleated form. When the solute molecular self-associates can't give sufficient information to predict the nucleated polymorph like INA-ethanol system, the method of introducing continuous ultrasonic irradiation in the nucleation stage was applied. The induction of ultrasound during nucleation process can break the original interactions firstly by shear forces and accelerate the occurrence of nucleation to avoid the reorientation and rearrangement of solute molecules. These strategies were proved to be effective in polymorph control and have a degree of applicability.

[Survey on infection source of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing]

Objective: To investigate the source and the transmission chain of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing. Methods: Epidemiological investigation were used to verify the exposure points of the cases. Close contacts were traced from the exposure points, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: A total of 112 cases of COVID-19 were reported in the epidemic from January 18 to February 6, 2022 in Beijing. Except for 1 case was uncertain, there were epidemiological links among 111 cases. The source of infection was the packages of imported cold-chain products from Southeast Asia, which were harvested and stored in a local cold-storage in January 2021, and packaged and sent to the cold-storage A in A district in June 2021, and then sold in batches in cold-storage B in B district from January 2022. The first case was infected in the handling of positive frozen products, and then 77 cases occurred due to working, eating and living together with the index case in the cold-storage B, cold-storage C and restaurant D. Besides the cold-storage B, C and the restaurant D, there were 16 sub-transmission chains, resulting in additional 35 cases. Conclusion: The epidemic indicated that the risk of 2019-nCoV infection from imported cold-chain products contaminated by package and highlighted the importance to strengthen the management of cold-chain industry in future.

SpringWorm: A Soft Crawling Robot with a Large-Range Omnidirectional Deformable Rectangular Spring for Control Rod Drive Mechanism Inspection

In this article, a cable-driven elastic backbone worm-like robot (named "SpringWorm") of decimeter-level size is designed, which has high adaptability in crack inspection of the weld between reactor pressure vessel (RPV) and control rod drive mechanisms. The robot consists of a body that adopts a rectangular helix spring backbone driven by four cables and the flexible claws embedded with distributed electromagnets. Combining the omnidirectional deformation of the backbone and the passive deformation adsorption of the claws, the robot can achieve a variety of gaits. Based on the approaches of geometric analysis and transformation matrices of the coordinate frame, a kinematic model of the cable-driven backbone has been established. Moreover, a mechanical model considering the friction between the cable and the backbone has also been established. The top position and the bending angle of the backbone obtained by the theory, simulation, and experiment are in good agreement. In addition, the errors of the driving force between simulation and experimental results are also small. SpringWorm is 670 g, measures 206 × 65 × 75 mm, has a maximum speed of 8.9 mm/s, and has a maximum payload of 1 kg. The robot can climb over 2-cm-tall steps and 4-cm-deep ditches, and climb and turn on the vertical wall, on the pipe with a radius of 31 cm, and on the spherical surface of RPV.

Cloning and base editing of GFP transgenic rhesus monkey and off-target analysis

We report the cloning of a 12-year-old transgenic green fluorescent protein (GFP) monkey by somatic cell nuclear transfer (SCNT) and base editing of the embryos, accompanied with safety evaluation of adenine base editors (ABEs). We first show the ability of ABEmax to silence GFP through A-to-G editing of the GFP sequence in 293T cells. Subsequently, using donor cells from a monkey expressing GFP, we have successfully generated 207 ABEmax-edited (SCNT-ABE) and 87 wild-type (SCNT) embryos for embryo transfer, genotyping, and genome and transcriptome analysis. SCNT-ABE and SCNT embryos are compared for off-target analysis without the interference of genetic variants using a new method named as OA-SCNT. ABEmax does not induce obvious off-target DNA mutations but induces widespread off-target RNA mutations, 35% of which are exonic, in edited monkey embryos. These results provide important references for clinical application of ABE.

[Progress in epidemiological research of norovirus infection]

With characteristics of high infectivity, diverse transmission routes and high variation, norovirus is the main pathogen of sporadic cases and outbreaks of acute gastroenteritis, resulting in a serious disease burden. This paper summarizes the latest progress in epidemiological research of norovirus infection from aspects of disease burden caused by acute gastroenteritis, virus variation and predominant strains, prevention and control measures, and immunization and vaccine development.

Rheumatoid arthritis and the risk of major cardiometabolic diseases: a Mendelian randomization study

OBJECTIVE

Rheumatoid arthritis (RA) is suggested to be implicated in the development of cardiometabolic diseases. We conducted a Mendelian randomization (MR) study to assess potential causality for associations of RA with the risk of cardiometabolic diseases, including type 2 diabetes (T2D), coronary artery disease (CAD), and ischaemic stroke.

METHOD

Seventy independent single-nucleotide polymorphisms (SNPs) associated with RA were identified as instrumental variables from a genome-wide association study (GWAS) of 58 284 European subjects. Summary-level data for the associations of the 70 genetic variants with T2D, CAD, and ischaemic stroke were taken from three GWASs with a total of 1 529 131 participants. Inverse-variance weighted (IVW) MR was used in the main analyses.

RESULTS

The main IVW MR analysis showed that genetically determined RA was associated with higher risks of T2D [odds ratio (OR): 1.04, 95% confidence interval (CI) 1.02-1.05; p < 0.001] and CAD (OR: 1.02, 95% CI 1.00-1.03; p = 0.012), but not ischaemic stroke (OR: 1.00, 95% CI 0.99-1.02; p = 0.961). Sensitivity analyses with multiple MR methods confirmed these associations. MR-Egger regression showed no evidence of pleiotropy in the association between genetically determined RA and the risk of T2D, CAD, and ischaemic stroke. Leave-one-out sensitivity analysis showed that the association between genetically determined RA and the risk of T2D, CAD, and ischaemic stroke was not driven by any individual SNP.

CONCLUSION

Genetically determined RA was associated with increased risks of T2D and CAD, suggesting that RA plays a crucial role in the pathogenesis of T2D and CAD.

Stabilizing bienzymatic cascade catalysis via immobilization in ZIF-8/GO composites obtained by GO assisted co-growth

Enzyme catalysis has clear advantages in the process of oxidizing glucose to produce gluconic acid. In the enzyme cascade, the improvement of the cascade efficiency is desired but challenging. Graphene oxide (GO) and ZIF-8 composites as enzyme support offer the promising opportunity that not only the cascade efficiency can be improved by control the distance between two enzymes, but also the stability can be improved. Here, a new strategy of GO assisted co-growth of ZIF-8 and enzyme was carried in a one-pot synthesis. Glucose oxidase&catalase immobilized in the ZIF-8/GO composites can obtain 98% residual activity after 15 days of storage with almost no enzyme shedding. The residual activity is still higher than 75% after 5 repeated uses. The presented method of controllable growth of metal organic frameworks on 2D nanosheet can also be extended for renewable energy devices, gas storage and separation of small molecules.

Fermented soybean meal increases nutrient digestibility via the improvement of intestinal function, anti-oxidative capacity and immune function of weaned pigs

The nutritional components of fermented soybean meal (FSBM) vary because of the complex process of microbial fermentation. The objective of this study was to investigate the nutritional value of FSBM from two sources and explore the mode of actions of FSBM on the improvement of nutrient digestibility with the measurements of digestive enzymes and serum biomarkers. Eight weaned barrows (initial BW: 14.12 ± 0.24 kg) equipped with T-cannula in the distal ileum were allotted to a duplicated 4 × 4 Latin-square design with four experimental diets and four periods. Four experimental diets included a soybean meal control diet, two FSBM diets, and a nitrogen-free diet. The two sources of FSBM increased the contents of CP, amino acid and lactic acid, while decreased the levels of anti-nutritional factors, including glycinin, β-conglycinin and trypsin inhibitors. Compared to soybean meal control diet, both FSBM diets significantly increased the apparent and standardised ileal digestibility of CP and amino acids (P < 0.05), increased the activities of lipase, maltase and invertase in digesta (P < 0.05), increased total antioxidant capacity, activities of glutathione peroxidase and superoxide dismutase, the levels of interleukin-4, IgA, IgG and IgM in serum (P < 0.05), while decreased the levels of diamine oxidase, malondialdehyde, interleukin-6, and interleukin-2 in serum (P < 0.05). Additionally, the standardised ileal digestibility of amino acids were highly correlated with the aforementioned digestive enzymes and health-related serum biomarkers. In summary, FSBM diets showed an improved nutritional value evidenced by the higher nutrient digestibility, which may be partially derived from its beneficial effects on intestinal integrity, anti-oxidative capacity and immune function.

[Etiological and epidemiological characteristics of Vibrio cholerae in Beijing, 2015-2021]

Objective: To analyze the etiological and epidemiological characteristics of Vibrio cholerae in Beijing during 2015-2021 and provide evidence for the prevention and control of cholera. Methods: The V. cholerae strains isolated in Beijing during 2015-2021 were analyzed by serotyping and virulence genes detection. Pulsed field gel electrophoresis (PFGE) was performed for the molecular typing of the strains. Based on the collected epidemiological and clinical data of cholera cases,the epidemiological characteristics of cholera were analyzed by descriptive epidemiology method. Results: A total of 76 Vibrio cholerae O1 strains were isolated in Beijing during 2015-2021, including 61 strains from human, 10 strains from environment and 5 strains from seafood. The 76 strains consisted of 68 Ogawa strains and 8 Inaba strains. Six Ogawa strains isolated from sporadic cases carried ctxAB. After NotⅠ digestion, 76 strains were divided into 33 PFGE patterns. From 2015 to 2021, a total of 38 cholera epidemics were reported in Beijing, most of them were sporadic ones, accounting for 92.11% (35/38). A total of 45 cases were reported, and the cases occurred during June-September accounted for 97.78% (44/45). Cholera cases occurred in 9 districts of Beijing, and the cases reported in Chaoyang district accounted for 42.22% (19/45) and in Changping district accounted for 31.11% (14/45). The age of the cholera cases ranged from 19 to 63 years. Except for one case with unknown clinical symptoms, 44 cases had diarrhea symptoms with 84.09% (37/44) of the cases reporting diarrhea (3-9 times/day), followed by yellow watery stool (95.45%, 42/44), abdominal pain (68.18%, 30/44), nausea and vomiting (40.91%, 18/44) and fever (36.36%, 16/44). Conclusion: Vibrio cholerae strains isolated in Beijing during 2015-2021 were mainly O1 serotype Ogawa,most of which were non-toxigenic. The PFGE of the strains varied. Cholera epidemics occurred in 9 districts of Beijing, but most were sporadic ones with incidence peak during June-September.

Degenerative Myelopathy and Neuropathy in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) Mice Caused by Lactate Dehydrogenase-Elevating Virus (LDV)

Following implantation of patient-derived xenograft (PDX) breast carcinomas from three separate individuals, 33/51 female NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ (NSG) mice presented with progressive, unilateral to bilateral, ascending hindlimb paresis to paralysis. Mice were mildly dehydrated, in thin to poor body condition, with reduced to absent hindlimb withdrawal reflex and deep pain sensation. Microscopically, there was variable axonal swelling, vacuolation, and dilation of myelin sheaths within the ventral spinal cord and spinal nerve roots of the thoracolumbar and sacral spinal cord, as well as within corresponding sciatic nerves. Results of PCR screening of PDX samples obtained at necropsy and pooled environmental swabs from the racks housing affected animals were positive for lactate dehydrogenase-elevating virus (LDV). LDV is transmitted through animal-animal contact or commonly as a contaminant of biologic materials of mouse origin. Infection is associated with progressive degenerative myelopathy and neuropathy in strains of mice harboring endogenous retrovirus (AKR, C58), or in immunosuppressed strains (NOD-SCID, Foxn1^nu), and can interfere with normal immune responses and alter engraftment and growth of xenograft tumors in immunosuppressed mice. This is the first reported series of LDV-induced poliomyelitis in NSG mice and should be recognized as a potentially significant confounder to biomedical studies utilizing immunodeficient xenograft models.

[Epidemiological characteristics of imported COVID-19 cases in Beijing]

Objective: To analyze the epidemiological characteristics of imported COVID-19 cases and the effect of vaccination on virus load and disease severity of the cases in Beijing. Methods: The data of the imported COVID-19 cases in Beijing were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and Epidemiology investigation. The data were processed and analyzed by Excel 2010 and SPSS 22.0. Results: From June 1 to September 30, 2021, a total of 171 imported COVID-19 cases were reported in Beijing, of which 66.67% (114/171) were asymptomatic. The cases were mainly from the Philippines, the United Arab Emirates, the United Kingdom and the Russian Federation, accounting for 67.84% (116/171). The male to female ratio of the cases was 2∶1 (114∶57). The median age M (Q₁, Q₃) of the cases was 28 (23, 36) years. The cases of Chinese accounted for 80.12% (137/171). The sequencing of the whole genome of the virus in 47 imported COVID-19 cases showed that the proportion of Delta variant was 76.60% (36/47). The COVID-19 vaccination coverage rate in the cases was 60.82% (104/171), but the full vaccination coverage rate was 53.80% (92/171). In the imported COVID-19 cases, 13.53% (23/170) were screened to be SARS-CoV-2 nucleic acid positive on the day when they arrived in Beijing, and all the cases were positive for 2019-nCoV nucleic acid within 28 days. The severity of the disease was higher in the unvaccinated group than in the partially vaccinated group and fully vaccinated group (P<0.001). In the unvaccinated group, there were 1 severe case and 1 critical case. The median Ct values M (Q₁, Q₃) of N gene and ORFlab gene in unvaccinated group were 32.51 (23.23, 36.06) and 32.78 (24.00, 36.38), respectively. There was no significant difference in the median of double-gene Ct value between the partially vaccinated group and the fully vaccinated group. Conclusions: During the study period, most of the imported COVID-19 cases in Beijing were asymptomatic. No matter vaccinated or not, the viral loads in the COVID-19 cases were similar, but the vaccination could reduce the severity of the disease.

[Survey of possible aerosol transmission of a COVID-19 epidemic caused by 2019-nCoV Delta variant]

Objective: To investigate the epidemiological characteristics and the transmission chain of a family clustering of COVID-19 cases caused by severe acute respiratory 2019-nCoV Delta variant in Changping district of Beijing. Methods: Epidemiological investigation was conducted and big data were used to reveal the exposure history of the cases. Close contacts were screened according to the investigation results, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: On November 1, 2021, a total of 5 COVID-19 cases caused by 2019-nCoV Delta variant were reported in a family detected through active screening. The infection source was a person in the same designated isolation hotel where the first case of the family cluster was isolated from 22 to 27, October. The first case was possibly infected through aerosol particles in the ventilation duct system of the isolation hotel. After the isolation discharge on October 27, and the first case caused secondary infections of four family members while living together from October 27 to November 1, 2021. Conclusion: 2019-nCoV Delta variant is prone to cause family cluster, and close attention needs to be paid to virus transmission through ventilation duct system in isolation hotels.

Antiretroviral Imprints and Genomic Plasticity of HIV-1 pol in Non-clade B: Implications for Treatment

Combinational antiretroviral therapy (cART) is the most effective tool to prevent and control HIV-1 infection without an effective vaccine. However, HIV-1 drug resistance mutations (DRMs) and naturally occurring polymorphisms (NOPs) can abrogate cART efficacy. Here, we aimed to characterize the HIV-1 pol mutation landscape in Cameroon, where highly diverse HIV clades circulate, and identify novel treatment-associated mutations that can potentially affect cART efficacy. More than 8,000 functional Cameroonian HIV-1 pol sequences from 1987 to 2020 were studied for DRMs and NOPs. Site-specific amino acid frequencies and quaternary structural features were determined and compared between periods before (≤2003) and after (2004-2020) regional implementation of cART. cART usage in Cameroon induced deep mutation imprints in reverse transcriptase (RT) and to a lower extent in protease (PR) and integrase (IN), according to their relative usage. In the predominant circulating recombinant form (CRF) 02_AG (CRF02_AG), 27 canonical DRMs and 29 NOPs significantly increased or decreased in RT during cART scale-up, whereas in IN, no DRM and only seven NOPs significantly changed. The profound genomic imprints and higher prevalence of DRMs in RT compared to PR and IN mirror the dominant use of reverse transcriptase inhibitors (RTIs) in sub-Saharan Africa and the predominantly integrase strand transfer inhibitor (InSTI)-naïve study population. Our results support the potential of InSTIs for antiretroviral treatment in Cameroon; however, close surveillance of IN mutations will be required to identify emerging resistance patterns, as observed in RT and PR. Population-wide genomic analyses help reveal the presence of selective pressures and viral adaptation processes to guide strategies to bypass resistance and reinstate effective treatment.

A proteomic approach to understand the impact of nodulation on salinity stress response in alfalfa (Medicago sativa L.)

Symbiotic nitrogen fixation in legumes is an important source of nitrogen supply in sustainable agriculture. Salinity is a key abiotic stress that negatively affects host plant growth, rhizobium-legume symbiosis and nitrogen fixation. This work investigates how the symbiotic relationship impacts plant response to salinity stress. We assayed the physiological changes and the proteome profile of alfalfa plants with active nodules (NA), inactive nodules (NI) or without nodules (NN) when plants were subjected to salinity stress. Our data suggest that NA plants respond to salinity stress through some unique signalling regulations. NA plants showed upregulation of proteins related to cell wall remodelling and reactive oxygen species scavenging, and downregulation of proteins involved in protein synthesis and degradation. The data also show that NA plants, together with NI plants, upregulated proteins involved in photosynthesis, carbon fixation and respiration, anion transport and plant defence against pathogens. The study suggests that the symbiotic relationship gave the host plant a better capacity to adjust key processes, probably to more efficiently use energy and resources, deal with oxidative stress, and maintain ion homeostasis and health during salinity stress.

The features of the crystal structure of the layered series hydrates of uridine-5'-monophosphate salts (UMPNa x ·yH2O)

Almost all reported salts of nucleotides crystallized from solutions are in the form of hydrate. Layered hydrates often occur in crystals with more than five water molecules per host molecule. In the present report, five single-crystal structures of uridine-5'-monophosphate (UMP) series hydrates of acid or salts (UMPNa _x ·yH₂O, x = 0-2) were determined and analysed. It was found that all crystal hydrates were orthorhombic with a C222₁ space group but with mere variation in the plane angle of adjacent bases and the distance between phosphate arms. The packing arrangements of UMPNa _x ·yH₂O hydrates present typical layered sandwich structures and show that the UMP molecular layers alternate with water molecular layers parallel to the ac plane, linked by hydrogen bonds or coupled with coordinate bonds besides ionic electrostatic interaction. Metal ions were located in water molecular layers as a form of hydration. In addition, we tried to deduce and give insights into the formation of UMPNa _x ·yH₂O hydrates. The effect of water molecules and metal ions on the crystal structure and stability was investigated. It was found that the coexistence of relatively rigid architectures constructed by host molecules and flexible interlayer regions was a key factor to the formation of these hydrates. Excessive loss of lattice water would give rise to the irreversible collapse of the host structure and loss of ability to recover to the initial state under humidity. Approximately seven crystal-water molecules were the balance point of sodium salt hydrates at room temperature under 43-76% RH conditions. The number of sodium ions in the crystal lattice is positively correlated with their thermal stability.

Enhanced Mechanical Properties of Polyvinyl Chloride-Based Wood–Plastic Composites With Pretreated Corn Stalk

Wood–plastic composites (WPCs) are a type of environmentally friendly materials widely used in daily life. This paper selected low-value biomass, corn stalk (CS), as the lignocellulosic resource for polyvinyl chloride (PVC)-based WPCs. To depict the relationship between lignocellulosic composition (cellulose, hemicellulose, and lignin) and mechanical performance of WPCs, pretreatments have been optimized to selective removal of lignin using an alkaline-EtOH stewing process and selective removal of hemicellulose using an acid stewing process. The αC sample, in which both lignin and hemicellulose were removed, shows the highest degree of crystallinity (72.60%) as estimated from X-ray diffraction analysis results and fibrous morphology with the highest aspect ratio as seen in scanning electron microscopy images. Compared with PVC/CS, PVC/αC gives a substantial increase in tensile strength and modulus by 37.21 and 21.66% and flexural strength and modulus by 29.98 and 34.88%, respectively. These improvements lie in the reinforcing effect of a fibrous structure and the improved interfacial compatibility as proven by scanning electron microscopy and dynamic mechanical analyzer results. Considering the extracted lignin and hemicellulose can be further developed to valuable biochemicals, the pretreatment to CS adds value to both WPC materials and biorefinery products.

Discovery and characterization of new crystal forms of bio-based nylon 4F salt

The transformation relationships between three new crystal forms of all-biobased nylon 4F salts.