SARS-CoV-2 NSP12 utilizes various host splicing factors for replication and splicing regulation.

The RNA-dependent RNA polymerase (RdRp) is a crucial element in the replication and transcription of RNA viruses. Although the RdRps of lethal human coronaviruses severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), SARS-CoV, and Middle East respiratory syndrome coronavirus (MERS-CoV) have been extensively studied, the molecular mechanism of the catalytic subunit NSP12, which is involved in pathogenesis, remains unclear. In this study, the biochemical and cell biological results demonstrate the interactions between SARS-CoV-2 NSP12 and seven host proteins, including three splicing factors (SLU7, PPIL3, and AKAP8). The entry efficacy of SARS-CoV-2 considerably decreased when SLU7 or PPIL3 was knocked out, indicating that abnormal splicing of the host genome was responsible for this occurrence. Furthermore, the polymerase activity and stability of SARS-CoV-2 RdRp were affected by the three splicing factors to varying degrees. In addition, NSP12 and its homologues from SARS-CoV and MERS-CoV suppressed the alternative splicing of cellular genes, which were influenced by the three splicing factors. Overall, our research illustrates that SARS-CoV-2 NSP12 can engage with various splicing factors, thereby impacting virus entry, replication, and gene splicing. This not only improves our understanding of how viruses cause diseases but also lays the foundation for the development of antiviral therapies.

[Characteristics and Impact Factors of Number Concentration of Primary Biological Aerosol Particles in Beijing].

Primary biological aerosol particles (PBAP) are an important part of ambient aerosols. Both living and dead organisms not only influence human health and air quality but also play important roles in regulating certain atmospheric processes and affect the hydrological cycle and climate change. In this study, flow cytometry (FCM) was utilized in combination with the simultaneous use of permeant (SYBR Green I) and impermeant (propidium iodide, PI) nucleic acid fluorescent staining to detect and quantify the viable and dead airborne biological particles. At the same time, based on this method, the dead/viable PBAP in a Beijing urban area was detected and quantified. Moreover, the influence of environmental factors on the concentrations of primary biological aerosol particles was illuminated. The results showed that the media number concentration of dead and alive PBAP in the Beijing urban area during summer (1.03×106 m-3 and 7.43×105 m-3, respectively) were higher than those during winter (7.34×105 m-3and 6.18×105 m-3, respectively). Statistical analysis showed that there was no significant correlation between PBAP number concentration and environmental factors, i.e., meteorological conditions and air quality, showing a weak positive correlation with temperature and humidity and weak negative correlations with O3, maximum wind speed, and sunshine duration. The number concentration of PBAP was weakly correlated with the mass concentration of PM2.5 but positively correlated with that of coarse particulate matter (PM2.5-10). Both stable weather and dust transport could increase the number concentration of PBAP in Beijing.

Primary nature of brown carbon absorption in a frigid atmosphere with strong haze chemistry.

Severe haze hovered over Harbin during the heating season of 2019-2020, making it one of the ten most polluted Chinese cities in January of 2020. Here we focused on the optical properties and sources of brown carbon (BrC) during the extreme atmospheric pollution periods. Enhanced formation of secondary BrC (BrCsec) was evident as relative humidity (RH) became higher, accompanied with a decrease of ozone but concurrent increases of aerosol water content and secondary inorganic aerosols. These features were generally similar to the characteristics of haze chemistry observed during winter haze events in the North China Plain, and indicated that heterogeneous reactions involving aerosol water might be at play in the formation of BrCsec, despite the low temperatures in Harbin. Although BrCsec accounted for a substantial fraction of brown carbon mass, its contribution to BrC absorption was much smaller (6 vs. 28%), pointing to a lower mass absorption efficiency (MAE) of BrCsec compared to primary BrC. In addition, emissions of biomass burning BrC (BrCBB) were inferred to increase with increasing RH, coinciding with a large drop of temperature. Since both the less absorbing BrCsec and the more absorbing BrCBB increased as RH became higher, the MAE of total BrC were largely unchanged throughout the measurement period. This study unfolded the contrast in the source apportionment results of BrC mass and absorption, and could have implications for the simulation of radiative forcing by brown carbon.

Strong biomass burning contribution to ambient aerosol during heating season in a megacity in Northeast China: Effectiveness of agricultural fire bans?

Sustainable use of crop residues remains a challenge in main agricultural regions of China such as the Northeast Plain. Here we investigated the impacts of biomass burning on fine particle (PM2.5) during a six-month long heating season in the Harbin-Changchun (HC) metropolitan area, China's only national-level city cluster located in the severe cold climate region. Temporal variation of PM2.5 was found to coincide with that of levoglucosan. This was attributed to the strong contribution of biomass burning to organic aerosol (the dominant component in PM2.5), as supported by the source apportionment results and high levoglucosan-to-organic carbon (OC) ratios. Furthermore, the variation of biomass burning contribution was inferred to be driven mainly by agricultural fires with relatively low combustion efficiencies, based on a synthesis of the relationship between OC and elemental carbon (EC), the dependence of EC on carbon monoxide, and the relative abundances of different tracers for biomass burning. Nitrate formation was enhanced during biomass burning episodes whereas no evidence was observed to indicate enhanced sulfate formation or net increase of OC mass due to secondary formation. This study demonstrates the importance of open burning as a source of haze pollution in the HC region.

Secondary inorganic aerosol during heating season in a megacity in Northeast China: Evidence for heterogeneous chemistry in severe cold climate region.

The characteristics of secondary inorganic aerosol including sulfate, nitrate and ammonium (SNA) were investigated during a six-month long heating season in the Harbin-Changchun metropolitan area, i.e., China's only national-level city cluster located in the severe cold climate region. The contribution of SNA to fine particulate matter (PM2.5) tended to decrease with increasing PM2.5 concentration, opposite to the trend repeatedly observed during winter in Beijing. Heterogeneous sulfate formation was still evident when the daily average temperature was as low as below -10 °C, with the preconditions of high relative humidity (RH; above ∼80%) and high nitrogen dioxide (above ∼60 µg/m3). Both the sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were enhanced at high RH, reaching ∼0.3. However, the high RH conditions were not commonly seen during the heating season, which should be responsible for the overall lack of linkage between the SNA contribution and PM2.5 temporal variation.

Investigation of the pharmacodynamic substances in dahuang zhechong pill that inhibit energy metabolism.

ETHNOPHARMACOLOGICAL RELEVANCE: Dahuang Zhechong pill (DHZCP) is a commonly used traditional Chinese medicine for the treatment of hepatocarcinoma. AIM OF THE STUDY: Previous studies have found that DHZCP can exert anti-hepatocarcinoma effects and reverse drug resistance by inhibiting energy metabolism. The goal of this study was to further explore the pharmacodynamic substances that inhibit energy metabolism. METHODS: The components of DHZCP absorbed into plasma were identified by UHPLC-Q-TOF-MS/MS. The Swiss and STITCH databases were used for target collection. The DAVID database was used for pathway enrichment analysis. Cytoscape software was used for network construction. The CCK-8 method detected cell viability. Chemiluminescence was used to detect ATP levels. RESULTS: A total of 89 components absorbed into plasma were identified by UHPLC-Q-TOF-MS/MS. Based on this, 24 potential pharmacodynamic substances were selected by network pharmacology. Among them, 11 components such as rhein can significantly inhibit ATP levels. CONCLUSIONS: Rhein, emodin, chrysophanol, hypoxanthine, baicalein, baicalin, wogonoside, acteoside, formononetin, isoliquiritigenin, and glycyrrhizic acid were the pharmacodynamic substances responsible for inhibition of energy metabolism of DHZCP.

In vitro effect of caveolin-1 as a slow-release material on bone-tendon junction healing: A comparative study.

Bone tendon junction injury is hard to cure because of its special anatomical structure, and the treatment applied for bone-tendon junction injury cannot result in the perfect vascular regeneration and restoration of the fibrocartilage zone. In this article, we aim to explore the effect of caveolin-1 as a slow-release material on bone-tendon junction healing. Seventy-two New Zealand rabbits were randomly selected and assigned into the experimental, sham-operated and control groups (n = 24). Caveolin-1 microspheres and microcapsule were developed as drug delivery system. At the 4th, 8th, and 12th weeks after surgery, quadriceps muscle patella-patellar tendon (QMPPT) was obtained from each rabbit to observe the tendon-to-bone tunnel healing, and X-ray examination, histological examination and biomechanical testing were applied for evaluating new bone formation. As the X-ray showed, caveolin-1 increased the new bone area at each time point. At the 4th and 8th weeks after surgery, the rabbit treated with caveolin-1 slow release material showed repair of fibrocartilage. According to the biomechanical results, the cross-sectional area, breaking load and ultimate tensile strength were increased along with time. At the same time point, caveolin-1 increased the ultimate tensile strength. Our study demonstrates that caveolin-1 as a slow-release material could accelerate bone-tendon junction healing by promoting the formation of the transition zone.

Anti-inflammatory effects of Morchella esculenta polysaccharide and its derivatives in fine particulate matter-treated NR8383 cells.

Fine particulate matter (PM2.5) exposure could cause many acute and chronic respiratory diseases. In this study the protective effects of polysaccharide from Morchella esculenta (FMP-1) and its derivatives against PM2.5-induced inflammation were evaluated. By flow cytometry and ELISA analysis, sulfated polysaccharide SFMP-1 showed the best protective effect in reducing PM2.5-induced cell death, cell apoptosis and production of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß), which was accompanied by a diminished level in reactive oxygen species (ROS) formation caused by PM2.5 in rat alveolar macrophage NR8383 cells. Furthermore, the mechanism was studied by immunofluorescence, qRT-PCR and western blotting. SFMP-1 could down-regulate the expression of inducible NO synthesis (iNOS) and cyclooxygenase-2 (COX-2) at both mRNA and protein levels in PM2.5-treated cells. The PM2.5-induced phosphorylation of nuclear factor-kappa B (NF-κB) was also reduced through suppressing nuclear translation of the NF-κB and inhibiting the degradation and phosphorylation of IκBα. These results indicated that SFMP-1 could protect NR8383 cells from PM2.5-induced inflammation by inhibiting NF-κB activation.

Uncertainties in thermal-optical measurements of black carbon: Insights from source and ambient samples.

Black carbon (BC) is important due to its complex influences on the environment and on climate in particular. However, reported BC data are largely dependent on measurement techniques due to the multitude of measurement principles. Here we focused on thermal-optical method which has been widely used to determine BC mass (as elemental carbon, EC). Several factors influencing EC measurement were investigated. Results from source samples representing vehicle engine emissions pointed to a continuum of EC components in thermal stability and provided direct observational evidence for the premature evolution of EC in inert atmosphere. It was also found that EC masses may be substantially underestimated for the vehicle exhaust samples if the adopted protocol requires an oxidizing atmosphere to define the split point between organic carbon (OC) and EC. Results from a field campaign conducted during winter in Beijing showed that the optical attenuation (ATN; i.e., the filter transmittance signal, I) was largely saturated for the samples with relatively high loadings, indicating their EC results were unreliable. Improved measurement of EC was achieved by extracting these heavily loaded filters using methanol, given that ATN was considerably reduced by the extraction and, moreover, saturation of ATN (or I) became not evident for the extracted samples. The methanol extraction also significantly reduced the transformation of OC to char-OC, by removing the majority (i.e., ~85%) of the deposited organic aerosols. Higher EC were measured for the extracted samples compared with the untreated ones, indicating that EC tends to be underestimated due to the charring-induced uncertainties. In addition, the methanol extraction largely reduced the inter-protocol discrepancy in the EC measurement results. Similar effects of methanol extraction have been observed during summer in Beijing, despite the seasonal variations of aerosol sources and compositions. This study indicates the potential benefits of methanol extraction for EC measurement.

The characteristics of carbonaceous aerosol in Beijing during a season of transition.

Carbonaceous aerosol was measured during fall of 2010 in Beijing. Daily variation of organic carbon (OC) was found to coincide with that of relative humidity (RH), and the OC to elemental carbon (EC) ratios were more than doubled during the more humid periods (RH above 0.75) compared to other conditions. This large increase in OC/EC could not be explained by the variations of primary biomass burning emissions but was accompanied by a five-fold increase in the sulfate to EC ratio. It was then inferred that secondary organic aerosol (SOA) formation was enhanced under the more humid conditions, presumably through aqueous-phase processes. This enhanced SOA formation might be partially associated with particles externally mixed with black carbon, as indicated by the RH-dependent relationships between aerosol optical attenuation and EC loading. In addition, organic aerosols exhibited different properties between the more humid and the other periods, such that they were less volatile and charred more significantly during thermal-optical analysis in the former case. These differences coincided with the evidence of enhanced SOA formation under the more humid conditions. This study highlights the necessity of incorporating aqueous-phase chemistry into air quality models for SOA.

[Comparison of Chemical Components Characteristics of PM2.5 Between Haze and Clean Periods During Summertime in Lin'an].

PM2.5 samples were collected at a background site of the Yangtze River Delta in China, during summertime, of which the carbonaceous components, i.e., OC and EC, and water-soluble inorganic ions, including sulfate, nitrate, and ammonium, were quantified. The average concentrations of OC and EC in PM2.5 during summer at Lin'an were (14.3±3.95) µg·m-3 and (3.33±1.47) µg·m-3, respectively. Compared to an urban site, the correlation between OC and EC during summertime in Lin'an, which was a rural site, was relatively weak (R2=0.31, P<0.01). The concentrations of secondary inorganic aerosols (sulfate as SO42-, nitrate as NO3-, and ammonium as NH4+) were much higher than those of other water-soluble inorganic ions, with average values of (8.70±5.66), (2.04±1.07), and (3.25±2.29) µg·m-3, respectively. Based on long-term intensive observations, combined with the analysis of back trajectory and fire spots observations, it was revealed that regional transport and stable synoptic conditions both play important roles in controlling the variations in aerosol chemical components. During the transition from clean to hazy days, the EC and POC fractions showed no obvious variation; in contrast, the SOC fraction decreased obviously. Unlike for SOAs, relative contributions of sulfate and ammonia to PM2.5 increased during hazy days, suggesting enhanced chemical production via other pathways for these two secondary inorganic ions, probably through heterogeneous reactions.

Clinical outcomes of frozen-thawed single blastocyst transfer in patients requiring whole embryo freezing.

We compared clinical outcomes amongst frozen-thawed cleavage-stage embryo, double and single blastocyst transfers in patients requiring whole embryo freezing. Data of infertile patients undergoing in-vitro fertilization and embryo transfer (IVF-ET) in our Reproductive Medicine Center from January 2010 to December 2012 were retrospectively analyzed. According to patients' wishes, patients were divided into cleavage-stage embryo transfer groups (group A, n = 456), double blastocyst transfer group (group B, n = 106), and single blastocyst transfer group (group C, n = 402). We found that the number of frozen embryos was significantly less in groups B and C than in group A (all p < 0.05), but the implantation rate was significantly higher in groups B and C as compared to group A (all p < 0.05). The clinical pregnancy rate and pregnancy rate per included cycle were significantly higher in group B than in groups A and C (all p < 0.05). The multiple pregnancy rate was significantly lower in group C than in groups A and B (all p < 0.05). The rate of early abortion was significantly lower in group C as compared to group A (p < 0.05). The data support the view that it may be the best clinical strategy for patients who require whole embryo freezing and have four or more Day 3 embryos available, to incubate Day 3 embryos into blastocysts, which are then vitrified for elective single blastocyst transfer.

[Composition and Source Apportionments of Saccharides in Atmospheric Particulate Matter in Beijing].

Based on the newly established high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), the saccharides in PM2.5 and PM10 in Beijing from 2011 - 2012 were quantified. Fourteen saccharides were synchronously detected in the aerosols samples in Beijing, which can be divided into three categories, i. e. anhydrosugar, sugar and sugar alcohol. Anhydrosugar, coming from biomass burning, include levoglucosan, mannosan and galactosan. Sugar and sugar alcohol, emitted by the primary biogenic emission, include glucose, fructose, trehalose, arabitol, mannitol, glycerol, threitol, 2-meythltrtols (2-methylthreitol and 2-methylerythrito), xylitol and inositol. The concentrations of monosaccharide anhydrides in summer and autumn were obviously higher than those in spring and winter, while the concentrations of sugar and sugar alcohol in winter were significantly lower than those in other seasons. The results of positive matrix factorization analysis suggested that saccharides compounds in atmospheric PM in Beijing can be derived from biomass burning, suspended soil or dust, isoprene SOA, as well as direct release of airborne fungal spores and pollen.

[Efficacy of the arthroscopic suture in meniscus anterior horn injury].

OBJECTIVE: To explore the clinical efficacy of the arthroscopic Mender II stapler for the treatment of patients with meniscus anterior horn injury needing meniscal suture repair. METHODS: Among 47 patients with meniscus anterior horn injury, 29 patients were male and 18 patients were female, ranging in age from 12 to 31 years old, with a mean age of (20.53± 4.12) years old. The duration of disease ranged from 3 to 35 days, and the average duration was (12.43±5.74) days. The Mender II stapler was used to carry out arthroscopic suture from outside to inside. The Lysholm knee scoring system was used to evaluate and analyze preoperative and postoperative symptoms, such as pain, limping embolism and so on. RESULTS: Forty-six patients were followed up, and the duration ranged from 12 to 48 months, with a mean of (20.53±4.12) years. The incision healed at the first stage without important vessels and nerves injuries. The symptoms of the locked knee joint disappeared, and symptoms such as pain, limp, swelling and limitation of activity improved. The Lysholm score increased from preoperative 52.33±7.31 to postoperative 86.74±6.92. CONCLUSION: Using Mender II stapler to treat patients with meniscus anterior horn injury who were treated with arthroscopic suture from outside to inside is effective to improve symptoms, and to obtain good short-term results.

The characteristics of Beijing aerosol during two distinct episodes: impacts of biomass burning and fireworks.

The chemical composition of Beijing aerosol was measured during summer and winter. Two distinct episodes were identified. Water-soluble potassium (K(+)) increased significantly during the firework episode in winter with an episode to non-episode ratio of 4.97, whereas the biomass burning (BB) episode in summer was characterized by high episode to non-episode ratios of levoglucosan (6.38) and K(+) (6.90). The BB and firework episodes had only a minor influence on the water-soluble OC (organic carbon) to OC ratio. Based on separate investigations of episode and non-episode periods, it was found that: (i) sulfate correlated strongly with both relative humidity and nitrate during the typical winter period presumably indicating the importance of the aqueous-phase oxidation of sulfur dioxide by nitrogen dioxide, (ii) oxalate and WSOC during both winter and summer in Beijing were mainly due to secondary formation, and (iii) high humidity can significantly enhance the formation potential of WSOC in winter.

[Study on ovary development in vitrification of embryos born mice and expression of growth differentiation factor 9].

OBJECTIVE: To study ovarian development in vitrification of embryos born mice and expression of growth differentiation factor 9 (GDF-9) in its. METHODS: The vitrification recovery embryos (vitrified-embryo group) and fresh embryos (fresh-embryo group) were transplanted into pseudopregnant mice, respectively. The female offspring mice in two groups were sacrificed on the 3(rd), 7(th), 14(th), 21(st), 28(th) and 60(th) day after birth, the ovarian tissues were taken, 6 mice in each time point of each group. The ovarian development was observed by HE staining, the expression of GDF-9 mRNA and protein at each time point of two groups were detected by reverse transcription (RT)-PCR and western blot. RESULTS: HE staining showed that no abnormal ovarian development was observed in offsprings at two groups. On the 3(rd), 7(th), 14(th), 21(st), 28(th) and 60(th) day after birth, the expression of GDF-9 mRNA in vitrified-embryo group were 0.14 ± 0.07, 0.42 ± 0.16, 1.00 ± 0.24, 1.59 ± 0.28, 2.05 ± 0.32 and 2.23 ± 0.21, respectively, which in fresh-embryo group were 0.13 ± 0.06, 0.45 ± 0.18, 1.00 ± 0.21, 1.56 ± 0.26, 2.01 ± 0.37 and 2.26 ± 0.23, respectively, there was no statistical difference between two groups (P > 0.05); the expression of GDF-9 protein in vitrified-embryo group were 0.040 ± 0.030, 0.120 ± 0.060, 0.170 ± 0.030, 0.250 ± 0.040, 0.320 ± 0.060 and 0.330 ± 0.010, respectively, which in fresh-embryo group were 0.030 ± 0.020, 0.110 ± 0.040, 0.150 ± 0.010, 0.210 ± 0.020, 0.360 ± 0.070 and 0.350 ± 0.030, respectively, there was no statistical difference between two groups (P > 0.05). CONCLUSION: The ovarian morphology in vitrification of embryos born mice and expression of GDF-9 in ovary has no any obvious change.