259 research outputs found
Reversibly tuning the insulating and superconducting state in KxFe2-ySe2 crystals by post-annealing
Since the discovery of superconductivity at 26 K in oxy-pnictide
LaFeAsO1-xFx, enormous interests have been stimulated in the field of condensed
matter physics and material sciences. Among the many kind of structures in the
iron pnictide superconductors, FeSe with the PbO structure has received special
attention since there is not poisonous pnictogen element in chemical
composition and its structure is the simplest one. However, the superconducting
transition temperature (Tc) in iron chalcogenide compounds is not enhanced as
high as other iron pnictide superconductors under ambient pressure until the
superconductivity at above 30 K in potassium intercalated iron selenide
KxFe2-ySe2 was discovered. The insulating and the superconducting state are
both observed in KxFe2-ySe2 with different stoichiometries and some groups have
tuned the system from insulating to superconducting state by varying the ratio
of starting materials[10, 11]. The recent data from neutron scattering suggest
that the superconductivity may be built upon an ordered state of Fe vacancies
as well as the antiferromagnetic state with a very strong ordered magnetic
moment 3.4 B. Here we show that the superconductivity can actually be tuned on
a single sample directly from an insulating state by post-annealing and fast
quenching. Upon waiting for some days at room temperatures, the
superconductivity will disappear and the resistivity exhibits an insulating
behavior again. The spatial distribution of the compositions of the as-grown
sample and the post-annealed-quenched one was analyzed by the Energy Dispersive
X-ray Spectrum (EDXS) and found to be very close to each other. Therefore it is
tempting to conclude that the superconductivity is achieved when the
Fe-vacancies are in a random (disordered) state. Once they arrange in an
ordered state by relaxation or slow cooling, the system turns out to be an
insulator.Comment: 12 pages,5 figure
Transcription Factor NFAT5 Promotes Glioblastoma Cell-driven Angiogenesis via SBF2-AS1/miR-338-3p-Mediated EGFL7 Expression Change
Glioblastoma (GBM) is the most aggressive primary intracranial tumor of adults and confers a poor prognosis due to high vascularization. Hence anti-angiogenic therapy has become a promising strategy for GBM treatment. In this study, the transcription factor nuclear factor of activated T-cells 5 (NFAT5) was significantly elevated in glioma samples and GBM cell lines, and positively correlated with glioma WHO grades. Knockdown of NFAT5 inhibited GBM cell-driven angiogenesis. Furthermore, long non-coding RNA SBF2 antisense RNA 1 (SBF2-AS1) was upregulated in glioma samples and knockdown of SBF2-AS1 impaired GBM-induced angiogenesis. Downregulation of NFAT5 decreased SBF2-AS1 expression at transcriptional level. In addition, knockdown of SBF2-AS1 repressed GBM cell-driven angiogenesis via enhancing the inhibitory effect of miR-338-3p on EGF like domain multiple 7 (EGFL7). In vivo study demonstrated that the combination of NFAT5 knockdown and SBF2-AS1 knockdown produced the smallest xenograft volume and the lowest microvessel density. NFAT5/SBF2-AS1/miR-338-3p/EGFL7 pathway may provide novel targets for glioma anti-angiogenic treatment
Atherosclerosis and Helminths Infection
Atherosclerosis is a chronic disease that causes various cardiovascular complications. Plaque formation in atherosclerosis is considered similar to the pathogenesis of other autoimmune diseases; thus, immunomodulation and immunosuppression may present strategies for the treatment and prevention of these diseases. Interestingly helminth infection was found to inhibit T helper 1-mediated autoimmune diseases and T helper 2-mediated allergy and asthma, indicating significant potential for clinical application. Some study even found that therapeutic efficacy of the viable tapeworm was superior to dexamethasone treatment. Recently, some studies have shown an inverse association between helminth infections and inflammatory diseases, including diabetes mellitus, lipid abnormality, and atherosclerosis. Will the underlying mechanism bring us a new idea on the treatment for these diseases? We tried to find an answer by reviewing recent articles
Evidence synthesis of Chinese medicine for monkeypox: Suggestions from other contagious pox-like viral diseases
Background: Monkeypox, a zoonotic disease caused by an Orthopoxvirus, presents an etiology similar to smallpox in humans. Currently, there are no licensed treatments for human monkeypox, so clear and urgent research on its prophylaxis and treatment is needed.
Objective: The purpose of this study was to explore the evidence of Chinese medicine for contagious pox-like viral diseases and provide suggestions for the multi-country outbreak management of monkeypox.
Methods: The review was registered on INPLASY (INPLASY202270013). Ancient classics in China and clinical trials involving randomized controlled trials , non-RCTs, and comparative observational studies of CM on the prevention and treatment of monkeypox, smallpox, measles, varicella, and rubella were retrieved from the Chinese Medical Code (fifth edition), Database of China Ancient Medicine, PubMed, the Cochrane Library, China National Knowledge Infrastructure, Chongqing VIP, Wanfang, Google Scholar, International Clinical Trial Registry Platform, and Chinese Clinical Trial Registry until 6 July 2022. Both quantitative and qualitative methods were applied to present the data collected.
Results: The use of CM to control contagious pox-like viral diseases was traced back to ancient Chinese practice cited in Huangdiâs Internal Classic, where the pathogen was recorded nearly two thousand years back. There were 85 articles (36 RCTs, eight non-RCTs, one cohort study, and 40 case series) that met the inclusion criteria, of which 39 studies were for measles, 38 for varicella, and eight for rubella. Compared with Western medicine for contagious pox-like viral diseases, CM combined with Western medicine showed significant improvements in fever clearance time (mean difference, â1.42 days; 95% CI, â1.89 to â0.95; 10 RCTs), rash/pox extinction time (MD, â1.71 days; 95% CI, â2.65 to â0.76; six RCTs), and rash/pox scab time (MD, â1.57 days; 95% CI, â1.94 to â1.19; five RCTs). When compared with Western medicine, CM alone could reduce the time of rash/pox extinction and fever clearance. Chinese herbal formulas, including modified Yinqiao powder, modified Xijiao Dihaung decoction, modified Qingjie Toubiao decoction, and modified Shengma Gegen decoction, were frequently applied to treat pox-like viral diseases and also showed significant effects in shortening the time of fever clearance, rash/pox extinction, and rash/pox scabs. Compared with Western medicine (placental globulin) or no intervention, eight non-randomized trials and observational studies on the prevention of contagious pox-like viral diseases showed a significant preventive effect of Leiji powder among high-risk populations.
Conclusion: Based on historical records and clinical studies of CM in managing contagious pox-like viral diseases, some botanical drugs could be an alternative approach for treating and preventing human monkeypox. Prospective, rigorous clinical trials are urgently needed to confirm the potential preventive and treatment effect of Chinese herbal formulas
Effect of dispersion on indistinguishability between single-photon wave-packets
With propagating through a dispersive medium, the temporal-spectral profile
of laser pulses should be inevitably modified. Although such dispersion effect
has been well studied in classical optics, its effect on a single-photon
wave-packet, i.e., the matter wave of a single-photon, has not yet been
entirely revealed. In this paper, we investigate the effect of dispersion on
indistinguishability of single-photon wave-packets through the Hong-Ou-Mandel
(HOM) interference. By dispersively manipulating two indistinguishable
single-photon wave-packets before interfering with each other, we observe that
the difference of the second-order dispersion between two optical paths of the
HOM interferometer can be mapped to the interference curve, indicating that (1)
with the same amount of dispersion effect in both paths, the HOM interference
curve must be only determined by the intrinsic indistinguishability between the
wave-packets, i.e., dispersion cancellation due to the indistinguishability
between Feynman paths; (2) unbalanced dispersion effect in two paths cannot be
cancelled and will broaden the interference curve thus providing a way to
measure the second-order dispersion coefficient. Our results suggest a more
comprehensive understanding of the single-photon wave-packet and pave ways to
explore further applications of the HOM interference
Genetic polymorphisms of CYP2A13 and its relationship to nasopharyngeal carcinoma in the Cantonese population
Nasopharyngeal carcinoma (NPC) is characterized by a high prevalence in Southern China, especially among Cantonese individuals of the Guangdong Province. Epidemiological studies have suggested that frequent exposure to high levels of nitrosamine from preserved foods such as salted fish could be a risk factor for NPC. Cytochrome P450 encompasses a family of enzymes that metabolize carcinogens and CYP2A13, a member of this family, is expressed predominantly in the respiratory tract with the highest levels in the nasal mucosa. In an effort to test whether a correlation exists between CYP2A13 genetic polymorphism and the risk of developing NPC, we sequenced all nine exons and the exon-intron junctions of the CYP2A13 gene in 45 NPC patients. We identified a total of 21 single nucleotide polymorphism (SNPs), including 7 novel SNPs. The most frequent functional variant allele was 74A-1757G-3375T-7233G with a haplotype frequency of 7.8% in the 45 NPC cases. In addition, a stop codon mutation was detected in one case. We then selected the 3 most frequent SNPs and one stop codon mutation to expand our study to a case-control analysis within the Cantonese population. A novel haplotype consisting 8 SNPs in introns, and four additional novel SNPs were identified; but no correlation between CYP2A13 genetic polymorphism and individual susceptibility to NPC was observed
Cancer survival: left truncation and comparison of results from hospital-based cancer registry and population-based cancer registry
BackgroundCancer survival is an important indicator for evaluating cancer prognosis and cancer care outcomes. The incidence dates used in calculating survival differ between population-based registries and hospital-based registries. Studies examining the effects of the left truncation of incidence dates and delayed reporting on survival estimates are scarce in real-world applications.MethodsCancer cases hospitalized at Nantong Tumor Hospital during the years 2002â2017 were traced with their records registered in the Qidong Cancer Registry. Survival was calculated using the life table method for cancer patients with the first visit dates recorded in the hospital-based cancer registry (HBR) as the diagnosis date (OSH), those with the registered dates of population-based cancer (PBR) registered as the incidence date (OSP), and those with corrected dates when the delayed report dates were calibrated (OSC).ResultsAmong 2,636 cases, 1,307 had incidence dates registered in PBR prior to the diagnosis dates of the first hospitalization registered in HBR, while 667 cases with incidence dates registered in PBR were later than the diagnosis dates registered in HBR. The 5-year OSH, OSP, and OSC were 36.1%, 37.4%, and 39.0%, respectively. The âlostâ proportion of 5-year survival due to the left truncation for HBR data was estimated to be between 3.5% and 7.4%, and the âdelayed-reportâ proportion of 5-year survival for PBR data was found to be 4.1%.ConclusionLeft truncation of survival in HBR cases was demonstrated. The pseudo-left truncation in PBR should be reduced by controlling delayed reporting and maximizing completeness. Our study provides practical references and suggestions for evaluating the survival of cancer patients with HBR and PBR
One-Step Synthesis of Monodisperse In-Doped ZnO Nanocrystals
A method for the synthesis of high quality indium-doped zinc oxide (In-doped ZnO) nanocrystals was developed using a one-step ester elimination reaction based on alcoholysis of metal carboxylate salts. The resulting nearly monodisperse nanocrystals are well-crystallized with typically crystal structure identical to that of wurtzite type of ZnO. Structural, optical, and elemental analyses on the products indicate the incorporation of indium into the host ZnO lattices. The individual nanocrystals with cubic structures were observed in the 5% InâZnO reaction, due to the relatively high reactivity of indium precursors. Our study would provide further insights for the growth of doped oxide nanocrystals, and deepen the understanding of doping process in colloidal nanocrystal syntheses
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