In the present study, we employed a
19
F NMR approach to study the association of telomere RNA and DNA
in vitro
and in living human cells. We successfully characterized the DNA-RNA hybrid ...G-quadruplex (HQ) structure formed by telomeric DNA and RNA. We further demonstrated for the first time that an HQ conformation can exist in the environmental conditions of HeLa cells.
In the present study, we employed a
19
F NMR approach to study the association of telomere RNA and DNA
in vitro
and in living human cells.
Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has ...been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.
Although the telomeric sequence has been reported to form various G-quadruplex topologies in vitro and in Xenopus laevis oocytes, in living human cells, the topology of telomeric DNA G-quadruplex ...remains a challenge. To investigate the human telomeric DNA G-quadruplex in a more realistic human cell environment, in the present study, we demonstrated that the telomeric DNA sequence can form two hybrid-type and two-tetrad antiparallel G-quadruplex structures by in-cell 19F NMR in living human cells (HELA CELLS). This result provides valuable information for understanding the structures of human telomeric DNA in living human cells and for the design of new drugs that target telomeric DNA.
Background and Aim
Previous smaller meta‐analyses comparing the incidence of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients treated with tenofovir disoproxil fumarate (TDF) ...versus entecavir (ETV) provided controversial results. This updated meta‐analysis aimed to reliably identify any difference in the HCC incidence between TDF‐treated or ETV‐treated CHB patients in general or in specific subgroups.
Methods
PubMed, EMBASE, Web of Science, and Cochrane Library were systematically searched for relevant studies with hazard ratios (HRs) for HCC between TDF‐treated and ETV‐treated CHB patients. Retrieved dates ranged from January 2009 to October 2021. HRs with or without adjustment were pooled with random‐effects model.
Results
Twenty‐four comparative studies involving 37 771 CHB patients treated with TDF and 72 094 treated with ETV were included. TDF was associated with lower risk of HCC compared with ETV, with pooled unadjusted HR of 0.76 (95% confidence interval CI: 0.67–0.86) (24 studies) and adjusted HR of 0.81 (95% CI: 0.72–0.91) (21 studies). In propensity score matching cohorts, the TDF superiority was confirmed for unadjusted HR 0.83 (95% CI: 0.71–0.97) (14 studies) and was close to significance for adjusted HR (0.78, 95% CI: 0.58–1.04) (8 studies). Subgroup analyses showed that TDF was associated with lower HCC risk than ETV treatment in CHB patients who were from Asia (adjusted HR: 0.76, 95% CI: 0.66–0.87; 15 studies) or nucleos(t)ide naïve (adjusted HR:0.74, 95% CI: 0.65–0.84; 18 studies).
Conclusion
Current evidence from a sizable population suggests that TDF is associated with significantly lower HCC risk compared with ETV treatment in patients who are from Asia and/or nucleos(t)ide naïve.
•ACE2 are highly expressed in human small intestinal enterocytes.•2019-nCoV may have same tissue tropism such as small intestine with SARS-CoV.•The gastrointestinal tract may be an alternative route ...for 2019-nCoV.•Distribution pattern of ACE2 gene insinuates the possibility of a fecal–oral transmission for COVID-19.
The coronavirus disease 2019 (COVID-19) was first reported in Wuhan, China and rapidly spread in other countries in December 2019. The infected patients presented with fever, respiratory symptoms, sometimes with digestive and other systemic manifestations, and some progressed with a severe acute respiratory syndrome or even death. Associated digestive symptoms were frequently observed in the patients, with an unknown significance and mechanism. ACE2, as the major known functional receptor of the 2019 novel coronavirus (2019-nCoV) attracted our attention. We collected the clinical data of the 2019-nCoV-infected patients from published studies and extracted the data about the incidence of gastrointestinal symptoms. Furthermore, we used online datasets to analyze ACE2 expression in different human organs, especially in the small intestine, to explore the relationship between ACE2 expression patterns and clinical symptoms. We found that diarrhea accounted for a notable proportion of COVID-19 patients, ranging from 8.0% to 12.9%. The results reveal that ACE2 mRNA and protein are highly expressed in the small intestinal enterocytes but not in the goblet cells or intestinal immune cells. High expression of ACE2 on the surface cells in the digestive tract may lead to gastrointestinal symptoms and inflammation susceptibility. Overall, digestive symptoms were common in the COVID-19 patients. ACE2 expression on surface cells of the small intestine may mediate the invasion and amplification of the virus and activation of gastrointestinal inflammation. It is a possible mechanism of digestive symptoms in the COVID-19 patients and explains the presence of the virus in patients’ stool samples. The study also highlights the necessity of taking stool samples for suspected patients to help in early diagnosis and assessment of disease status.
Optical methods to manipulate and detect nanoscale objects are highly desired in both nanomaterials and molecular biology fields. Optical tweezers have been used to manipulate objects that range in ...size from a few hundred nanometres to several micrometres. The emergence of near-field methods that overcome the diffraction limit has enabled the manipulation of objects below 100 nm. A highly free manipulation with signal-enhanced real-time detection, however, remains a challenge for single sub-100-nm nanoparticles or biomolecules. Here we show an approach that uses a photonic nanojet to perform the manipulation and detection of single sub-100-nm objects. With the photonic nanojet generated by a dielectric microlens bound to an optical fibre probe, three-dimensional manipulations were achieved for a single 85-nm fluorescent polystyrene nanoparticle as well as for a plasmid DNA molecule. Backscattering and fluorescent signals were detected with the enhancement factors up to ∼10
and ∼30, respectively. The demonstrated approach provides a potentially powerful tool for nanostructure assembly, biosensing and single-biomolecule studies.
A simple and efficient synthesis of NBN‐doped conjugated polycyclic aromatic hydrocarbons (such as diazaborinines) has been accomplished by a catalyst‐free intermolecular dehydration reaction at room ...temperature between boronic acid and diamine moieties with yields up to 99 %. Polycyclic aromatic hydrocarbons with a six‐membered NBN ring are a new class of aggregation‐induced emissive luminogens. Extremely sensitive detection of ppb levels of TNT by phenyl naphthodiazaborinine is straightforward. Visual detection of TNT is illustrated by fabrication of TNT test strips, which can detect as little as 100 ng of TNT powder. This simple and sensitive detection of TNT has potential applications in the area of public safety and security against terrorist activities.
Sensitive to explosives: A simple and efficient room‐temperature, catalyst‐free dehydration method is reported for the synthesis of NBN‐doped polycyclic aromatic hydrocarbons. These contain naphthodiazaborinines, a new class of AIEgen capable of detection of TNT at the ppb level.
Background and Aim
Remimazolam tosilate (RT) is a new short‐acting GABA(A) receptor agonist, having potential to be an effective option for procedural sedation. Here, we aimed to compare the efficacy ...and safety of RT with propofol in patients undergoing upper gastrointestinal endoscopy.
Methods
This positive‐controlled, non‐inferiority, phase III trial recruited patients at 17 centers, between September 2017 and November 2017. A total of 384 patients scheduled to undergo upper gastrointestinal endoscopy were randomly assigned to receive RT or propofol. Primary endpoint was the success rate of sedation. Adverse events (AEs) were recorded to evaluate safety.
Results
The success rate of sedation in the RT group was non‐inferior to that in the propofol group (97.34% vs 100.00%; difference in rate −2.66%, 95% CI −4.96 to −0.36, meeting criteria for non‐inferiority). Patients in the RT group had longer time to adequate sedation (P < 0.0001) but shorter time to fully alert (P < 0.0001) than that in the propofol group. The incidences of hypotension (13.04% vs 42.86%, P < 0.0001), treatment‐related hypotension (0.54% vs 5.82%, P < 0.0001), and respiratory depression (1.09% vs 6.88%, P = 0.0064) were significantly lower in the RT group. AEs were reported in 74 (39.15%) patients in the RT group and 114 (60.32%) patients in the propofol group, with significant difference (P < 0.0001).
Conclusion
This trial established non‐inferior sedation success rate of RT compared with propofol. RT allows faster recovery from sedation compared with propofol. The safety profile is favorable and appears to be superior to propofol, indicating that it was feasible and well tolerated for patients.
•Rate-based model of the typical CO2 capture process by aqueous MEA solution is built.•The new model is validated by the recently published pilot-scale experimental results.•The profiles of the ...temperature and the concentration of CO2 in the liquid phase are predicted accurately.•Important insights have been obtained on the function of washing sections.
An improved rate-based model of the typical CO2 capture process by aqueous MonoEthanolAmine (MEA) solution is built within Aspen Plus V8.0 software in this study. The improved model is built on the basis of an example model coming along with Aspen Plus V8.0, and thermodynamic model of ENRTL-RK is adopted. Improvements include the washing section of the absorption column is strictly modelled by a separate column, and the error on mass balance of MEA is greatly reduced. The new model is validated by the recently published pilot-scale experimental results of the absorption of CO2 by MEA solution, in which both absorption and desorption columns are equipped with the structured packing Sulzer Mellapak 250.Y™. It predicts the experimental profiles of the temperature and the concentration of CO2 in the liquid phase with an accuracy of ±4%, and obviously much better than recently reported model with an accuracy of ±8%. Important insights have been obtained on the function of washing sections on the top of both absorber and desorption column, the factors to determine the flowrates of make-up water and recycle water around the washing section of the absorber are first analyzed.
Here we report an iridium-catalyzed asymmetric umpolung allylation of imines as a general approach to prepare 1,4-disubstituted homoallylic amines, a fundamental class of compounds that are hitherto ...not straightforward to obtain. This transformation proceeds by a cascade involving an intermolecular regioselective allylation of 2-azaallyl anions and a following 2-aza-Cope rearrangement, utilizes easily available reagents and catalysts, tolerates a substantial scope of substrates, and readily leads to various enantioenriched, 1,4-disubstituted homoallylic primary amines.
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