Applications of nanomaterials in COVID-19 pandemic.

The novel coronavirus 2019 (COVID-19) pandemic represents one of the biggest global health threats in the last two decades, so researchers around the world are searching for solutions and treatments for COVID-19. At the time of writing, there are no specific drugs that have demonstrated suitable effectiveness in treating COVID-19. The current challenge involves designing tools for the prevention, rapid and accurate diagnosis, drug delivery, and effective treatment of this novel coronavirus. In this short review, we discuss how nanotechnology offers new ways to combat COVID-19, and how nanomaterials can be applied to control the COVID-19 outbreak. We also summarize relevant studies regarding the use of nanomaterials for preventing viral spread, preparing vaccines, and diagnosing coronavirus, as well as studies that show how nanoparticles can be used as drug delivery systems for the treatment of viral infections. Research on nanotechnology-based diagnosis, drug delivery, and antiviral therapy is currently in the early stages. However, the unique chemical properties of some nanomaterials highlight the broad prospect of nanomaterials in the future, and we propose that they will play an important role in the fight against COVID-19.

T4 Pili Promote Colonization and Immune Evasion Phenotypes of Nonencapsulated M4 Streptococcus pyogenes.

Streptococcus pyogenes (group A Streptococcus [GAS]) is an important human pathogen causing a broad spectrum of diseases and associated with significant global morbidity and mortality. Almost all GAS isolates express a surface hyaluronic acid capsule, a virulence determinant that facilitates host colonization and impedes phagocyte killing. However, recent epidemiologic surveillance has reported a sustained increase in both mucosal and invasive infections caused by nonencapsulated GAS, which questions the indispensable role of hyaluronic acid capsule in GAS pathogenesis. In this study, we found that pilus of M4 GAS not only significantly promotes biofilm formation, adherence, and cytotoxicity to human upper respiratory tract epithelial cells and keratinocytes, but also promotes survival in human whole blood and increased virulence in murine models of invasive infection. T4 antigen, the pilus backbone protein of M4 GAS, binds haptoglobin, an abundant human acute-phase protein upregulated upon infection and inflammation, on the bacterial surface. Haptoglobin sequestration reduces the susceptibility of nonencapsulated M4 GAS to antimicrobial peptides released from activated neutrophils and platelets. Our results reveal a previously unappreciated virulence-promoting role of M4 GAS pili, in part mediated by co-opting the biology of haptoglobin to mitigate host antimicrobial defenses.IMPORTANCE Group A Streptococcus (GAS) is a strict human pathogen causing more than 700 million infections globally each year. The majority of the disease-causing GAS are encapsulated, which greatly guarantees survival and dissemination in the host. Emergence of the capsule-negative GAS, such as M4 GAS, in recent epidemiologic surveillance alarms the necessity to elucidate the virulence determinants of these pathogens. Here, we found that M4 pili play an important role in promoting M4 GAS adherence and cytotoxicity to human pharyngeal epithelial cells and keratinocytes. The same molecule also significantly enhanced M4 GAS survival and replication in human whole blood and experimental murine infection. T4 antigen, which composes the backbone of M4 pili, was able to sequester the very abundant serum protein haptoglobin to further confer M4 GAS resistance to antibacterial substances released by neutrophils and platelets.

[Effects of ant colonization on spatiotemporal variation of organic carbon mineralization in Xishuangbanna tropical forest soils]. / 蚂蚁筑巢对西双版纳热带森林土壤碳矿化动态的影响.

Ants as ecosystem engineers can increase the input of soil organic matter, change soil physicochemical properties, and stimulate microbial activities through their colonization, thus affecting the spatiotemporal dynamics of soil organic carbon mineralization. We explored the spatiotemporal characteristics of carbon mineralization rates in ant nests and the adjacent soils in Syzygium oblatum community of Xishuangbanna, Yunnan. We analyzed the association of the variation in carbon mineralization rates with soil physicochemical properties. We found that ant colonization had a significant effect on soil organic carbon mineralization. The mean carbon mineralization rate was 19.2% higher in nest soils than that in the surrounding soils. The monthly carbon mineralization rate in nest soils and the reference soils was ranked as June ＞ September ＞ March ＞ December. The highest increase of carbon mineralization rate in ant nests was observed in 10-15 cm soil layer, while that in the reference soils was in 0-5 cm soil depth. Ant colonization had a significant effect on soil physicochemical properties. Compared with reference soils, soil temperature, soil water, soil organic carbon,soil microbial carbon, total nitrogen, hydrolytic nitrogen, nitrate, and ammonium increased by 7.6%, 5.4%, 9.9%, 14.8%, 13.4%, 9.9%, 24.1%, 6.6% and 19.4%, respectively. In contrast, soil bulk density and soil pH were decreased by 1.4% and 2.5%, respectively. Results from correlation coefficients and principal component analysis (PCA) showed that soil organic carbon and soil microbial carbon were the key factors controlling the mineralization of soil organic carbon, followed by total nitrogen, hydrolyzed nitrogen, ammonium, nitrate, temperature, and soil moisture. We conclude that ant colonization mainly alter the substrate components (i.e., soil organic carbon and microbial biomass carbon) of soil organic carbon mineralization and thus affect its spatio-temporal dynamics in Xishuangbanna tropical forests.

[Effects of ant nesting on soil microbial biomass carbon and quotient in tropical forest of Xishuangbanna.] / 蚂蚁筑巢对西双版纳热带森林土壤微生物生物量碳及熵的影响.

Ant nesting can modify soil physicochemical conditions in the tropical forest, exerting a crucial effect on spatiotemporal variation in soil microbial biomass carbon and quotient. In this study, the chloroform fumigation method was used to measure the spatiotemporal dynamics of microbial biomass carbon and quotient in ant nests and the reference soils in Syzygium oblatum community of tropical Xishuangbanna. The results were as following: 1) Microbial biomass carbon and quotient were significantly higher in ant nests (1.95 g·kg-1, 6.8%) than in the reference soils (1.76 g·kg-1, 5.1%). The microbial biomass carbon in ant nests and the reference soils showed a signifi-cantly unimodal temporal variation, whereas the temporal dynamics of microbial biomass quotient presented a distribution pattern of "V" type. 2) The microbial biomass carbon and quotient showed significant vertical changes in ant nests and the reference soils. The microbial biomass carbon decreased, and microbial biomass quotient increased significantly along the soil layers. The vertical variations in microbial biomass carbon and quotient were more significant in ant nests than in refe-rence soils. 3) Ant nesting significantly changed the spatiotemporal distributions of soil water and temperature in ant nests, which in turn affected spatiotemporal dynamics of soil microbial biomass carbon and quotient. Soil water content could explain 66%-83% and 54%-69% of the variation of soil microbial biomass carbon and quotient, respectively. Soil temperature could explain 71%-86% and 67%-76% of the variation of soil microbial biomass carbon and quotient in ant nests and the reference soils, respectively. 4) Changes in soil physicochemical properties induced by ant nesting had significant effect on the soil microbial biomass carbon and quotient. There were positive correlations of soil microbial biomass carbon to soil organic carbon, soil temperature, total nitrogen and soil water content, and to bulk density, nitrate nitrogen and hydrolyzed nitrogen; whereas a negative correlation of them was observed with soil pH. Soil pH was positively and other soil physicochemical properties were negatively correlated with microbial biomass quotient. Total organic carbon, total nitrogen and soil temperature had greater contribution to microbial biomass carbon, while total organic carbon and total nitrogen had the least negative effect on microbial biomass quotient. Therefore, ant nesting could modify microhabitats (e.g., soil water and soil temperature) and soil physicochemical properties (e.g., total organic carbon and total nitrogen), thereby regulating the spatiotemporal variation in soil microbial biomass carbon and quotient in tropical forests.

[Effects of ant nesting on the spatiotemporal dynamics of soil easily oxidized organic carbon in Xishuangbanna tropical forests, China]. / 蚂蚁筑巢对西双版纳热带森林土壤易氧化有机碳时空动态的影响.

Ant nesting can form microhabitat and soil nutrient condition in their nests that is diffe-rent from the surrounding environment, thus having a crucial effect on the variation of soil easily oxidized organic carbon (EOC). In this study, the Mallotus paniculatus communities in Menglun Tropical Botanical Garden of Xishuangbanna, Chinese Academy of Sciences was taken as the research object. We compared the spatiotemporal distribution of soil EOC in ant nests and the refe-rence soils, and analyzed the relationship of the variation in soil EOC to the changes in soil physicochemical properties. The results showed that soil EOC in ant nests and the reference soils had a unimodal change trend with months. The order was ranked as June>September>March>December. The soil EOC decreased with the soil layers. The EOC was higher in 0-5 cm nest soils than in the refe-rence soils, while it was not significantly different in the 5-10 cm and 10-15 cm soil layers. Ant nesting increased soil temperature, soil organic carbon, soil easily oxidized organic carbon, soil microbial biomass carbon, total nitrogen, soil nitrate nitrogen and hydrolysis nitrogen, but reduced the soil water content and bulk density. The impacts of ant nesting on soil ammonium and pH was not significant. The soil organic carbon and microbial biomass carbon had crucial roles in regulating the spatiotemporal variation in EOC in ant nests and the reference soils, whereas the effects of soil temperature, soil water content, total nitrogen and nitrate nitrogen ranked the second. The ant nesting had a crucial effect on the spatiotemporal variations in easily oxidized organic carbon, mainly through changing the microhabitat (e.g., soil temperature and moisture) and soil nutrients (e.g., soil organic carbon and microbial biomass carbon) in Xishuangbanna tropical forests.

In vitro and In vivo Antioxidant Activity of Flavonoid Extracted from Mulberry Fruit (Morus alba L.).

BACKGROUND: Many plants possess antioxidants that exhibit additive or synergistic activities. OBJECTIVE: In this study, an ethanol-extracted flavonoid extracted from mulberry fruit (FEM) was evaluated for the antioxidant activity in vitro and the hemolysis in red blood cell (RBC) and lipid peroxidation in liver in vivo. MATERIALS AND METHODS: Antioxidant activities in vitro were measured by quantifying its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, reducing power, and Fe(2+)-chelating ability. FEM inhibits hemolysis in RBCs and effects of lipid peroxidation in the liver were estimated. RESULTS: The total content of flavonoid compounds was 187.23 mg of quercetin equivalents per grams dried material. In the in vitro assays, FEM demonstrated a strong antioxidant effect, especially in DPPH scavenging activity and reducing power. Mouse RBC hemolysis induced by H2O2 was significantly inhibited by FEM in a dose- and time-dependent manner. The effects of FEM on lipid peroxidation in liver, mitochondria, and microsome were investigated. The percentage of inhibition at high concentration (100 µg/mL) of FEM was 45.51%, 39.36%, and 42.78% for liver, mitochondria, and microsomes, respectively. These results suggest that the FEM possesses a strong antioxidant activity both in vivo and in vitro. SUMMARY: The total content of flavonoid compounds in mulberry fruit was 187.23 mg/g dried materialFEM showed a strong antioxidant effect, especially in 2,2-diphenyl-1-picrylhydrazyl scavenging activity and reducing powerMouse red blood cell hemolysis induced by H2O2 was significantly inhibited by FEM in a dose- and time-dependent mannerThe inhibition percentage at high concentration of FEM was 45.51%, 39.36%, and 42.78% for mouse's liver, mitochondrial, and microsomes, respectively. Abbreviations used: FEM: Flavonoid Extracted from Mulberry fruit, H2O2: Hydrogen peroxide, DPPH: 2,2-diphenyl-1-picrylhydrazyl, EDTA: Ethylene diamine tetraacetic acid, MDA: malondialdehyde, TBA: 2-thiobarbituric acid, RBC: Red blood cells, DNJ: 1-deoxynojirimycin, LDL: low density lipoprotein, ROS: reactive oxygen species, EDTA2Na: Ethylenediaminetetraacetic acid disodium salt.

Determination of gardenia yellow colorants in soft drink, pastry, instant noodles with ultrasound-assisted extraction by high performance liquid chromatography-electrospray ionization tandem mass spectrum.

A novel, rapid and simple analytical method was developed for the quantitative determination of crocin, crocetin and geniposide in soft drink, pastry and instant noodles. The solid samples were relatively homogenized into powders and fragments. The gardenia yellow colorants were successively extracted with methanol using ultrasound-assisted extraction. The analytes were quantitatively measured in the extracts by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. High correlation coefficients (r(2)>0.995) of crocin, crocetin and geniposide were obtained within their linear ranges respectively (50-1000ng/mL, 50-1000ng/mL, 15-240ng/mL) by external standard method. The limits of detection (LODs) were 0.02µg/g for crocin, 0.01µg/g for crocetin and 0.002µg/g for geniposide. And the limits of quantitation (LOQs) were in the ranges of 0.05-0.45µg/g for crocin, and in the ranges of 0.042-0.32µg/g for crocetin, and in the ranges of 0.02-0.15µg/g for geniposide in soft drink, pastry and instant noodles samples. The average recoveries of crocin, crocetin and geniposide ranged from 81.3% to 117.6% in soft drink, pastry and instant noodles. The intra- and inter-day precisions were respectively in the range of 1.3-4.8% and 1.7-11.8% in soft drink, pastry and instant noodle. The developed methods were successfully validated and applied to the soft drink, pastry, and instant noodles collected from the located market in Beijing from China. Crocin, crocetin and geniposide were detected in the collected samples. The average concentrations ranged from 0.84 to 4.20mg/g for crocin, and from 0.62 to 3.11mg/g for crocetin, and from 0.18 to 0.79mg/g for gardenia in various food samples. The method can provide evidences for government to determine gardenia yellow pigments and geniposide in food.

A simple, accurate, time-saving and green method for the determination of 15 sulfonamides and metabolites in serum samples by ultra-high performance supercritical fluid chromatography.

An analytical method based on ultra-high performance supercritical fluid chromatography (UHPSFC) with photo-diode array detection (PDA) has been developed to quantify 15 sulfonamides and their N4-acetylation metabolites in serum. Under the optimized gradient elution conditions, it took only 7min to separate all 15 sulfonamides and the critical pairs of each parent drug and metabolite were completely separated. Variables affecting the UHPSFC were optimized to get a better separation. The performance of the developed method was evaluated. The UHPSFC method allowed the baseline separation and determination of 15 sulfonamides and metabolites with limit of detection ranging from 0.15 to 0.35µg/mL. Recoveries between 90.1 and 102.2% were obtained with satisfactory precision since relative standard deviations were always below 3%. The proposed method is simple, accurate, time-saving and green, it is applicable to a variety of sulfonamides detection in serum samples.

Human umbilical cord blood-derived mononuclear cell transplantation: case series of 30 subjects with hereditary ataxia.

BACKGROUND: The differential diagnosis for hereditary ataxia encompasses a variety of diseases characterized by both autosomal dominant and recessive inheritance. There are no curative treatments available for these neurodegenerative conditions. This open label treatment study used human umbilical cord blood-derived mononuclear cells (CBMC) combined with rehabilitation training as potential disease modulators. METHODS: 30 patients suffering from hereditary ataxia were treated with CBMCs administered systemically by intravenous infusion and intrathecally by either cervical or lumbar puncture. Primary endpoint measures were the Berg Balance Scale (BBS), serum markers of immunoglobulin and T-cell subsets, measured at baseline and pre-determined times post-treatment. RESULTS: A reduction of pathological symptoms and signs was shown following treatment. The BBS scores, IgG, IgA, total T cells and CD3+CD4 T cells all improved significantly compared to pre-treatment values (P < 0.01~0.001). There were no adverse events. CONCLUSION: The combination of CBMC infusion and rehabilitation training may be a safe and effective treatment for ataxia, which dramatically improves patients' functional symptoms. These data support expanded double blind, placebo-controlled studies for these treatment modalities.

Ultrasound probe pressure but not maternal Valsalva maneuver alters Doppler parameters during fetal middle cerebral artery Doppler ultrasonography.

OBJECTIVE: To determine the effects of increased ultrasound probe pressure and maternal Valsalva maneuver (VM) on the middle cerebral artery (MCA) Doppler ultrasonography in fetuses. METHODS: A total of 120 healthy pregnant women in second and third trimesters were enrolled in the study. MCA blood flow was measured by pulsed Doppler sonography in 60 fetuses (24 and 40 weeks' gestation) before and after the application of increased ultrasound probe pressure. In the other 60 fetuses (32 and 36 weeks' gestation), sonography was performed before and after maternal VM. Statistical analysis was performed by paired t-test. RESULTS: The pressure induced by the ultrasound probe induced a significant increase in the pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV); however, a significant decrease was found in the end-diastolic velocity (EDV) (p < 0.05). No statistically significant difference was found in the mean flow velocity (MFV). Moreover, maternal VM did not have any effect on the PI, RI, EDV, or MFV. CONCLUSION: Fetal MCA Doppler assessment is affected by increased probe pressure but not by maternal VM. Thus, the application of the MCA Doppler sonography should be undertaken in the head of fetuses without any probe pressure and without maternal VM.

[Study on determination of sodium, vanadium and aluminum contents in fuel oil by ICP-AES].

The present paper considers synthetically all kinds of factors affecting excitation spectrum under traditional measurement conditions of fluorescence matter in liquor using plasma atomic emission spectra. The input power, carrier gas flow and assistant gas flow for BEC of Na, V, Al were optimized by testing. The input power, carrier gas flow and assistant gas flow for Na are 950 W, 0.6 L x min(-1) and 1.0 L x min(-1), respectively. The input power, carrier gas flow and assistant gas flow for V are 1 150 W, 0.5 and 1.1 L x min(-1), respectively. The input power, carrier gas flow and assistant gas flow for Al are 1 150 W, 0.6 and 1.0 L x min(-1), respectively. The result shows that the method is sensitive, accurate, linear in a wide range and highly precise. The precision is between 1.7%-2.2%, the linear ranges are between 0-100 mg x L(-1) and recoveries are between 96%-105%.