[Research on the framework of biosafety standards for pathogenic microbial laboratories]

Developing and implementing biosafety standards for pathogenic microbiology laboratories is essential to achieving scientific, efficient, and standardized management and operation. This article analyzes the current standardization construction in biosafety in pathogenic microbiology laboratories domestically and internationally. It proposes a framework for the biosafety standard system of pathogenic microbiology laboratories, which mainly includes four parts: basic standards, management standards, technical standards, and industry applications. It provides a reference for the standardization work of pathogenic microbiology laboratories and helps to standardize the biosafety industry in China.

[Characteristics of nutrient accumulation and vertical spatial distribution in Cunninghamia lanceolata plantation with different stand densities]

The growth, biomass, nutrient content and accumulation as well as the vertical distribution of nutrient accumulation in Cunninghamia lanceolata plantation across densities of 1800, 3000, 4500 trees·hm^-2 were stu-died in order to provide scientific basis for efficient cultivation of C. lanceolata plantation. The total amounts of nutrients accumulated in C. lanceolata plantation with 1800, 3000, 4500 trees·hm^-2 were 1311.57, 2531.55 and 2307.33 kg·hm^-2, respectively. There were significant variations among different densities. Under the same density, the order of nutrient content and accumulation in C. lanceolata plantation was total N > total K > total Ca > total Mg > total P. Moreover, the amount of nutrients in trunk and bark decreased with the increases of tree height. The amount of nutrient accumulation in persistent withered branch and leaf were allocated from middle to the upper part of tree, while the opposite was observed for fresh branch and leaf. N accumulation increased with the increases of stand densities, while the other nutrients first increased then decreased. The order of the amount of nutrient accumulation in trunk, bark, root, persistent withered branch, persistent withered leaf and litter among different densities was 4500 > 3000 > 1800 trees·hm^-2, and was 3000 > 1800 > 4500 trees·hm^-2 in fresh branch and leaf, and 1800 > 3000 > 4500 trees·hm^-2 in understory. Under the densities of 1800 and 4500 trees·hm^-2, the nutrient distribution ratio in bark was the largest, accounting for 21.6% and 19.4%. In 3000 trees·hm^-2, the distribution ratio of fresh leaves reached its maximum, accounting for about 22.9%, and the next was fresh branches, which had a distribution ratio of about 17.8%. 3000 trees·hm^-2 was the most appropriate density for nutrient accumulation and distribution in C. lanceolata plantation.

[Interpretation for the group standards in technical specification for health risk investigation of central air conditioning ventilation system during coronavirus disease 2019 epidemic]

The central air conditioning ventilation system plays an important role in the air circulation of buildings such as centralized isolation medical observation points and general public buildings. In order to meet the requirements of COVID-19 epidemic prevention and control, Beijing Preventive Medicine Association organized Beijing CDC and other professional institutes to write up the group standard entitled "Technical specification for health risk investigation of central air conditioning ventilation system during the COVID-19 epidemic (T/BPMA 0006-2020)" . According to the particularity of central air conditioning ventilation system risk control during the outbreak of similar respiratory infectious diseases, based on current laws and regulations and the principle of scientific, practical, consistency and normative, 8 key points of risk investigations were summarized, which were the location of fresh air outlet, air conditioning mode, air return mode, air system, air distribution, fresh air volume, exhaust and air conditioner components. The contents, process, method, data analysis and conclusion of the investigation implementation were also defined and unified. It could standardize and guide institutions such as disease control and health supervision to carry out relevant risk managements, and provided solutions and technical supports for such major public health emergencies in city operations.

[Effects of undergrowth vegetation management measures on the soil bacterial community structure of large diameter timber plantation of Cunninghamia lanceolata]

Given the importance of undergrowth vegetation to plantation ecosystem, this study analyzed the effects of three kinds of understory management measures, including understory preservation, understory removal, and interplanting, on the soil bacterial diversity, community structure and relative abundance under large diameter timber plantation of Cunninghamia lanceolata using high-throughput sequencing technology. The relationship between soil physical and chemical properties and bacterial community diversity were analyzed. The results showed that Chao1, Ace and Shannon indices of soil bacterial communities of understory preservation were higher than those of understory removal and interplanting. Actinobacteria, Acidobacteria and Chloroflexi were the dominant bacteria groups in the soil of C. lanceolata plantation. Compared with understory removal and interplanting, the relative abundance of Proteobacteria, Planctomycetes, Firmicutes and Verrucomicrobia in the soil of understory preservation was relatively high, while that of Actinobacteria, Acidobacteria and Chloroflexi was relatively low. There were significant differences in the relative abundance of Firmicutes, Planctomycetes, Verrucomicrobia, Parcubacteria and Actinobacteria among three understory management measures. The contents of moisture, total nitrogen, total phosphorus, hydrolyzed nitrogen and available phosphorus in the soil were important factors affecting soil bacterial community structure. Soil bacterial diversity indices had significant positive correlation with the contents of total nitrogen, total phosphorus, total potassium, hydrolyzed nitrogen and available potassium in the soil.

[CT perfusion analysis on the association of permeability surface with hematoma and edema volume in acute spontaneous putaminal and thalamic hematoma]

Objective: To discuss the correlation of permeability surface (PS) with hematoma and edema volume in acute spontaneous putaminal and thalamic hematoma using CT perfusion imaging. Methods: A total of 48 acute spontaneous putaminal and thalamic hemorrhage patients were enrolled in this study during October 2015 and December 2016 at the First Affiliated Hospital of Wenzhou Medical University. At the image slice with maximum size of hematoma, PS was measured by drawing various regions of interest (ROI) including"hot spots", perihematomal regions, outward regions, hemisphere regions and contralateral mirror regions. The relative PS (rPS) was calculated as the ratio of ipsilateral to contralateral PS value in each ROI. Hematoma and edema volumes were traced and obtained with commercial software. Results: The"hot spots"PS ((2.8±1.5) ml·100 g(-1)·min(-1)) and perihematomal PS ((2.1±1.4) ml·100 g(-1)·min(-1)) were both significantly higher than the PS of the contralateral mirror regions ((1.1±0.5) ml·100 g(-1)·min(-1)) (P<0.001). There was no significant difference in outward regions PS and contralateral mirror regions PS (P>0.05), nor in hemisphere regions PS and contralateral mirror regions PS (P>0.05). There was no significant difference in"hot spots"rPS and perihematomal rPS (P=0.218). The"hot spots"rPS and Perihematomal rPS were both higher than the rPS of the outward and hemisphere regions (P<0.01). There was no significant difference in the outward and hemisphere regions (P<0.01). The median hematoma volume was 12.63 ml and the median edema volume was 12.36 ml. The edema volume had a positive association with the hematoma volume(r=0.799, P<0.001) and perihematomal PS(r=0.465, P=0.001). Perihematomal PS had a positive association with the hematoma volume (r=0.386, P=0.007). Conclusion: The damage of blood-brain barrier around acute spontaneous hematoma can be measured via CT perfusion imaging. Perihematomal PS was associated with the hematoma and edema volume.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

[Analysis of CT perfusion imaging in chronic cerebral circulatory insufficiency and its relationship with crossed cerebellar diaschisis]

Objective: To investigate the change of cerebral microcirculation of chronic cerebral circulation insufficiency(CCCI) patients and the relationship between CCCI and crossed cerebellar diaschisis(CCD)by using 320-detector row of low-dose volume CT perfusion imaging. Methods: A total of 158 patients (103 males, 55 females, from 45 to 82 years old, the mean age was 62.9) with symptoms of CCCI were admitted to the First Affiliated Hospital of Wenzhou Medical University from June 2013 to January 2016. Low-dose CTP imaging of whole brain was performed to them using 320-detector row volume CT scanner. The perfusion parameters such as cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT), time to peak(TTP) and DLY in both cerebral blood supply areas and cerebellum were got, so were the 4-dimensional CTA images, and rCBF, rCBV, rMTT and rTTP were calculated by ipsilateral/contralateral value. Comparative t-test and independent t-test were applied to analyzing these parameters quantitatively.Chi-square test and Logistic regression model were applied to analyzing the related clinical risk factors. Results: (1) All 108 patients in CCCI group showed asymmetric perfusion within two cerebral hemispheres in CTP images. The CBF, CBV of diseased side were lower than the contralateral mirror area (t(CBF)=-12.89, t(CBV)=-7.031, P(CBF, CBV)<0.001); the MTT of the diseased side was shorter than the contralateral mirror area (t(MTT) =13.310, P(MTT)<0.001); the TTP of the diseased side was longer than the contralateral mirror area (t(TTP)=-4.012, P(TTP)<0.001). The rCBF and rCBV of CCCI group were lower than that in non-CCCI group (t(rCBF)=3.079, t(rCBV)=2.760, P(rCBF, rCBV)<0.01), while the rTTP of CCCI group was longer than that in non-CCCI group (t(rTTP)=4.846, P(rTTP)<0.001). (2)The results of Chi-square test showed that the differences of gender (χ(2)=4.036, P=0.045), hyperlipidemia (χ(2)=7.687, P=0.006), as well as smoking (χ(2)=11.868, P=0.001) had statistical significance between CCCI group and non-CCCI group.Multi-factor Logistic regression analysis showed that hyperlipidemia (OR value=3.736, P=0.016) and smoking (OR value=4.641, P=0.01) were the risk factors of CCCI, while gender had no relationship with it.(3)The incidence of CCD was 18.5% in the CCCI group, and at the same time, the supratentorial corresponding blood supply areas were classified.A total of 10(34.5%) cases were in blood supply area of posterior cerebral artery, 6(20.7%) cases were in blood supply area of middle cerebral artery, 12(41.4%) cases were of anterior cerebral artery, while only 1(3.5%) case was of basal ganglia, in which 4 cases were in blood supply area of posterior cerebral artery, another 4 cases were middle cerebral artery, 7 cases were of anterior cerebral artery and no case of basal ganglia respectively leading CCD alone. Conclusions: CTP could display the microcirculation situation of abnormal brain tissue perfusion area intuitively and quantitatively. Additionally, it could reflect the degree of relationship between cerebral several blood supply areas and cerebellum.

Analysis of ROP signaling in the leaf epidermis of mutant tomato with low-energy ion beam

The importance of the ROP small GTPase signaling pathway in the regulation of cellular polarity growth in eukaryotes has been thoroughly studied. In this study, we examined the LeROP small GTPase (related to Arabidopsis thaliana genome LeROP GTPase in tomato) signaling of cell polarity growth in the mutant (M-1) tomato. Interestingly, we detected expansive growth of epidermis cells in M-1, in which the leaves appeared slightly lobed shaped. However, we observed jigsaw puzzle shaped and deeply lobed shaped leaves in wild-type leaf epidermis cells. The t-test showed significant difference (P < 0.05). Based on previous studies of the AtROP gene in Arabidopsis leaf epidermis cells, we hypothesized that the growth of mutant M-1 tomato leaf epidermis cell is related to AtROP gene signal transmission. The results of reverse transcription-polymerase chain reaction showed the expression of LeROP2, LeROP4, and LeROP7 in M-1 mutants were stronger than in wild-type cells. At the flowering stage, LeROP2 GTPase showed no expression in wild-type cells, but was expressed in mutant cells. This study revealed a link between the low-energy ion beam and the ROP GTPase signaling pathway in tomato. In addition, the ROP gene changes analyzed suggest a new mechanism for mutations following low-energy ion beam implantation.

Use of bone mesenchymal stem cells to treat rats with acute liver failure

This study aimed to isolate mesenchymal stem cells from bone mesenchymal stem cells (BMSCs), determine their therapeutic potential for treating rats with acute liver failure (ALF), further explore the factors that induce liver failure mechanisms, and elucidate the role of bone marrow stem cell therapy and BMSCs on liver homing. We found that differentiation potential was present in BMSCs expressing high levels of CD29 and CD90. These cells improved liver functioning in vivo after transplantation into rat livers with D-galactosamine damage, as evidenced by the levels of alanine aminotransferase and aspartate aminotransferase returning to normal (low levels) in recipient ALF rats. A significant improvement in the liver functional test and histological findings was observed in the transplantation group after 120 and 168 h of transplantation (P < 0.05). Histological data revealed that hepatocyte cell apoptosis was lower in the transplantation group compared to the control groups (P < 0.05), and that the transplantation of BMSCs reduced liver inflammation, decreased hepatic denaturation and necrosis, and promoted liver regeneration. These ameliorations were not recorded in the control groups. The results of in situ hybridization, immunofluorescence staining, and Western blot confirmed the presence of transplanted BMSCs in recipient rat livers. Stromal cell derived factor-1 alpha and vascular endothelial growth factor were significantly upregulated after the intraportal transplantation of BMSCs, with significantly higher levels being found in the portal vein and the tail vein groups (P < 0.05). In conclusion, BMSCs have a therapeutic effect against ALF rats, evoke endogenous repair mechanisms in the liver, and may represent a novel form of therapeutic intervention for the disease. Furthermore, intraportal transplantation serves as a more effective pathway compared to tail vein transplantation.

[QTL analysis for epistatic effects and QTL x environment interaction effects on final height of rice (Oryza sativa L.)]

QTLs with epistatic effects and environmental interaction effects for final height of rice were studied by mixed-model based QTL mapping with a doubled haploid population from IR64/Azucena in four environments. The results demonstrated the importance of epistasis as a genetic basis of the quantitative traits and also revealed several important features of this phenomenon. In the results, 100 per cent of QTLs were involved in epistasis, of which 64 per cent were found with significant additive effects. This might mean that the usual estimates of the QTL additive effects could be confounded by epistatic interactions and result in biased estimation unless epistatic effect is separated. The other 36 per cent did not have any significant additive effects of their own but were involved in 48 per cent of the identified epistatic interactions. Such loci might play the role of modifying agents that tend to activate other loci or modify the action of other loci. The other features of epistasis include as follows: it was fairly common for the same locus to get involved in interactions with more than one locus; the QTLs with relatively high magnitude of effects might also be involved in epistasis; and epistasis was sensitive to environmental interactions for their expression. QTL x environment (QE) interaction effects were detected more often than QTL main effects for plant height behavior, as might indicate that gene expression could be greatly affected by environments.

A facile method for the solution and solid-phase synthesis of substituted [3.3.1] bicycles

[reaction: see text] Interest in bicyclic natural products from the Guttiferae classification has led to the development of an improved method for the selenium-mediated cyclization of alkenyl-substituted beta-dicarbonyls (I) to form a variety of bicyclo[3.3.1]nonan-9-ones (II) both in solution and on solid support.