3,475 research outputs found

    Coronal condensations caused by magnetic reconnection between solar coronal loops

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    Employing Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) multi-wavelength images, we report the coronal condensation during the magnetic reconnection (MR) between a system of open and closed coronal loops. Higher-lying magnetically open structures, observed in AIA 171 A images above the solar limb, move downward and interact with the lower-lying closed loops, resulting in the formation of dips in the former. An X-type structure forms at the interface. The interacting loops reconnect and disappear. Two sets of newly-reconnected loops then form and recede from the MR region. During the MR process, bright emission appears sequentially in the AIA 131 A and 304 A channels repeatedly in the dips of higher-lying open structures. This indicates the cooling and condensation process of hotter plasma from ~0.9 MK down to ~0.6 MK, and then to ~0.05 MK, also supported by the light curves of the AIA 171 A, 131 A, and 304 A channels. The part of higher-lying open structures supporting the condensations participate in the successive MR. The condensations without support by underlying loops then rain back to the solar surface along the newly-reconnected loops. Our results suggest that the MR between coronal loops leads to the condensation of hotter coronal plasma and its downflows. MR thus plays an active role in the mass cycle of coronal plasma because it can initiate the catastrophic cooling and condensation. This underlines that the magnetic and thermal evolution has to be treated together and cannot be separated, even in the case of catastrophic cooling.Comment: 10 pages, 6 figure

    2-Amino-4,6-dimethyl­pyrimidin-1-ium 1-oxo-2,6,7-trioxa-1λ5-phosphabicyclo­[2.2.2]octane-4-carboxyl­ate

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    In the title compound, C6H10N3 +·C5H6O6P−, the cation and anion are linked by pairs of N—H⋯O hydrogen bonds. There are additional inter­molecular N—H⋯N hydrogen bonds, which generate centrosymmetric tetramers of two cations and two anions

    catena-Poly[[[aqua­silver(I)]-μ-4,4′-bipyridine-κ2 N:N′] 4-amino­benzoate nitrate hydrate]

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    In the structure of the title compound, 2[Ag(C10H8N2)(H2O)](C7H6NO2)(NO3)·H2O, the AgI atom is three-coordinated in a T-shaped configuration by two N atoms from two symmetry-related 4,4′-bipyridine (bipy) ligands at short distances and by one water O atom at a longer distance. Each bipy ligand bridges two neighbouring AgI atoms, forming a chain structure extending parallel to [101]. The complete 4-amino­benzoate anion, the nitrate anion and the uncoordinated water mol­ecule are located on mirror planes: together with the coordinated water mol­ecule, they form N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, stabilizing the crystal structure

    Re-evaluation of the carcinogenic significance of hepatitis B virus integration in hepatocarcinogenesis

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    To examine the role of hepatitis B virus (HBV) integration in hepatocarcinogenesis, a systematic comparative study of both tumor and their corresponding non-tumor derived tissue has been conducted in a cohort of 60 HBV associated hepatocellular carcinoma (HCC) patients. By using Alu-polymerase chain reaction (PCR) and ligation-mediated PCR, 233 viral-host junctions mapped across all human chromosomes at random, no difference between tumor and non-tumor tissue was observed, with the exception of fragile sites (P = 0.0070). HBV insertions in close proximity to cancer related genes such as hTERT were found in this study, however overall they were rare events. No direct correlation between chromosome aberrations and the number of HBV integration events was found using a sensitive array-based comparative genomic hybridization (aCGH) assay. However, a positive correlation was observed between the status of several tumor suppressor genes (TP53, RB1, CDNK2A and TP73) and the number of chromosome aberrations (r = 0.6625, P = 0.0003). Examination of the viral genome revealed that 43% of inserts were in the preC/C region and 57% were in the HBV X gene. Strikingly, approximately 24% of the integrations examined had a breakpoint in a short 15 nt viral genome region (1820-1834 nt). As a consequence, all of the confirmed X gene insertions were C-terminal truncated, losing their growth-suppressive domain. However, the same pattern of X gene C-terminal truncation was found in both tumor and non-tumor derived samples. Furthermore, the integrated viral sequences in both groups had a similar low frequency of C1653T, T1753V and A1762T/G1764A mutations. The frequency and patterns of HBV insertions were similar between tumor and their adjacent non-tumor samples indicating that the majority of HBV DNA integration events are not associated with hepatocarcinogenesis

    Synergistic binding of actinomycin D and echinomycin to DNA mismatch sites and their combined anti-tumour effects

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    Combination cancer chemotherapy is one of the most useful treatment methods to achieve a synergistic effect and reduce the toxicity of dosing with a single drug. Here, we use a combination of two well-established anticancer DNA intercalators, actinomycin D (ActD) and echinomycin (Echi), to screen their binding capabilities with DNA duplexes containing different mismatches embedded within Watson-Crick base-pairs. We have found that combining ActD and Echi preferentially stabilised thymine-related T:T mismatches. The enhanced stability of the DNA duplex-drug complexes is mainly due to the cooperative binding of the two drugs to the mismatch duplex, with many stacking interactions between the two different drug molecules. Since the repair of thymine-related mismatches is less efficient in mismatch repair (MMR)-deficient cancer cells, we have also demonstrated that the combination of ActD and Echi exhibits enhanced synergistic effects against MMR-deficient HCT116 cells and synergy is maintained in a MMR-related MLH1 gene knockdown in SW620 cells. We further accessed the clinical potential of the two-drug combination approach with a xenograft mouse model of a colorectal MMR-deficient cancer, which has resulted in a significant synergistic anti-tumour effect. The current study provides a novel approach for the development of combination chemotherapy for the treatment of cancers related to DNA-mismatches

    AMT: All-Pairs Multi-Field Transforms for Efficient Frame Interpolation

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    We present All-Pairs Multi-Field Transforms (AMT), a new network architecture for video frame interpolation. It is based on two essential designs. First, we build bidirectional correlation volumes for all pairs of pixels, and use the predicted bilateral flows to retrieve correlations for updating both flows and the interpolated content feature. Second, we derive multiple groups of fine-grained flow fields from one pair of updated coarse flows for performing backward warping on the input frames separately. Combining these two designs enables us to generate promising task-oriented flows and reduce the difficulties in modeling large motions and handling occluded areas during frame interpolation. These qualities promote our model to achieve state-of-the-art performance on various benchmarks with high efficiency. Moreover, our convolution-based model competes favorably compared to Transformer-based models in terms of accuracy and efficiency. Our code is available at https://github.com/MCG-NKU/AMT.Comment: Accepted to CVPR202

    Severe 2009 H1N1 infection in early pregnancy

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    AbstractObjectiveBecause pregnancy suppresses the immune system, women at any stage of pregnancy are more susceptible to bacterial and viral infection. Pregnant women might thus be at increased risk of complications from pandemic H1N1 virus infection, and illness may progress rapidly.Case ReportA 23-year-old primigravida at 9 weeks’ gestation was presented to our institution because of the sudden onset of sore throat, fever, chills, and vomiting for 5 days. She was diagnosed with early pregnancy H1N1 infection, vulvar herpes infection, and impending intravascular disseminated coagulopathy. Oseltamivir (Tamiflu) 75 mg and valacyclovir 500 mg were then administered orally twice daily for 5 days. The patient’s fever, chills, and vomiting subsided 2 days later. The real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis of nasal discharge for influenza virus types A and B showed positive results for the A/H1N1 influenza virus. The early pregnancy was terminated by therapeutic curettage at the patient’s request. The surgical specimen revealed products of conception with the presence of necrotic chorionic villi, and focal lymphocytes in decidual tissue. RT-PCR analysis of gestational tissue for A/H1N1 was negative.ConclusionPregnant women with H1N1 infection seem to benefit from antiviral therapy
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