To investigate the pathogens, clinical manifestations, prognosis of and the risk factors for pulmonary mycosis in China.
All cases of pulmonary mycosis from 16 centers in 10 cities from Jan. 1998 to ...Dec. 2007 that met the diagnostic criteria were included for clinical, microbiological and radiological analysis.
Totally 474 cases of pulmonary mycosis were retrieved. The top 5 pulmonary mycosis was pulmonary aspergillosis (180 cases, 37.9%), pulmonary candidiasis (162 cases, 34.2%), pulmonary cryptococcosis (74 cases, 15.6%), pneumocystis carinii pneumonia (23 cases, 4.8%) and pulmonary mucormycosis (10 cases, 2.1%). The constituent ratio in the last 3 years was similar to that in the former 7 years. The main pathogens of pulmonary candidiasis were Candida albicans (308/474, 65.0%) and Candida tropicalis (57/474, 12.0%), which were sensitive to common azoles. Compared with bacterial pneumonia, pulmonary mycosis showed more symptoms of hemoptysis (147/474, 31.0%) and pleural effusion (95/474, 20.0%), and less ra
This paper presents a model in which some sophisticated investors do not wait for receipt of a signal before purchasing an asset. Its critical innovation is an arbitrage equation for frontrunning. ...Some sophisticates who will receive information in the next period arbitrage against similar sophisticates who will act on that information in that next period when the information is received. The costs of such frontrunning are borne totally by unsophisticated traders-with no gain or loss to sophisticates. Nor does the frontrunning produce any information discovery. Thus, this paper describes a financial-market anomaly: of inefficient financial transactions with gains to no one.
Hypoxia-inducible factor-2α (HIF2α) is a major determinant factor of invasion and metastasis in various tumors. It has been reported that HIF2α is overexpressed in many tumors, including gastric ...cancer. However, the roles of HIF2α in the progression of gastric cancer are still not clear. In this study, we first examined the levels of HIF2α in gastric cancer by using immunohistochemistry, western blot and real-time PCR analysis. The results showed that HIF2α was highly expressed in gastric cancers compared to non-neoplastic mucosa and significantly correlated with histologic grade, TNM stages and peritoneal dissemination. MTT and colony formation assay revealed HIF2α overexpression induced high proliferation in BGC823 cells and HIF2α knockdown significantly inhibited proliferation in SGC7901 cells. Furthermore, we demonstrated that HIF2α could promote migration and invasion in gastric cancer cells. The results of western blot and RT-PCR analysis indicated that Survivin, Cyclin D1, MMP2 and MMP9 are upregulated with HIF2α overexpression. Finally, similar roles of HIF2α also in vivo were demonstrated. Taken together, the present study suggested that HIF-2α was involved in proliferation, metastasis and invasion of gastric cancer cells, with the induction of Survivin, Cyclin D1, MMP2 and MMP9 expression.
A fluorescence biosensor was developed for the ultrasensitive detection of the available lead in soil samples by coupling with DNAzyme and hairpin DNA cyclic assembly. The biorecognition between lead ...and 8-17 DNAzyme will cleave the substrate strands (DNA2) and release the trigger DNA (T), which can be used to initiate the DNA assembly reactions among the hairpins (H1, H2, and H3). The formed Y-shaped sensing scaffold (H1-H2-H3) contains active Mg2+-DNAyzmes at three directions. In the presence of Mg2+, the BHQ and FAM modified H4 will be cleaved by the Mg2+-DNAyzme to generate a high fluorescence signal for lead monitoring. The linear range of the fluorescence biosensor is from 1 pM to 100 nM and the detection limit is 0.2 pM. The biosensor also exhibited high selectivity and the nontarget competing heavy metals did not interfere with the detection results. Compare with the traditional method (DTPA+ICP-MS) for the available lead detection, the relative error (Re) is in the range from −8.3 % to 9.5 %. The results indicated that our constructed fluorescence biosensor is robust, accurate, and reliable, and can be applied directly to the detection of the available lead in soil samples without complex extraction steps.
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•DNAzyme biorecognition-induced DNA cyclic assembly was used to construct the biosensor.•Hairpin probes were used to build the Y-shaped sensing scaffold.•The linear range of the biosensor is from 1 pM to 100 nM and the detection limit is 0.2 pM.•The assay is robust and has been applied to the detection of the available lead in soil samples.
The uranyl ion (UO22+) is the most stable form of uranium, which exhibits high toxicity and bioavailability posing a severe risk to human health. The construction of ultrasensitive, reliable, and ...robust sensing techniques for UO22+ detection in water and soil samples remains a challenge. Herein, a DNA network biosensor was fabricated for UO22+ detection using DNAzyme as the heavy metal recognition element and double-loop hairpin probes as DNA assembly materials. UO22+-activated specific cleavage of the DNAzyme will liberate the triggered DNA fragment, which can be utilized to launch a double-loop hairpin probe assembly among Hab, Hbc, and Hca. Through multiple cyclic cross-hybridization reactions, hexagonal DNA duplex nanostructures (nHab•Hbc•Hca) were formed. This DNA network sensing system generates a high fluorescence response for UO22+ monitoring. The biosensor is ultrasensitive, with a detection limit of 2 pM. This sensing system also displays an excellent selectivity and robustness, enabling the DNA network biosensor to work even in complex water and soil samples with excellent accuracy and reliability. With the advantages of enzyme-free operation, outstanding specificity, and high sensitivity, our proposed DNA network biosensor provides a reliable, simple, and robust method for trace levels of UO22+ detection in environmental samples.
The uranyl ion (UO2 2+) is the most stable form of uranium, which exhibits high toxicity and bioavailability posing a severe risk to human health. The construction of ultrasensitive, reliable, and ...robust sensing techniques for UO2 2+ detection in water and soil samples remains a challenge. Herein, a DNA network biosensor was fabricated for UO2 2+ detection using DNAzyme as the heavy metal recognition element and double-loop hairpin probes as DNA assembly materials. UO2 2+-activated specific cleavage of the DNAzyme will liberate the triggered DNA fragment, which can be utilized to launch a double-loop hairpin probe assembly among Hab, Hbc, and Hca. Through multiple cyclic cross-hybridization reactions, hexagonal DNA duplex nanostructures (nHab•Hbc•Hca) were formed. This DNA network sensing system generates a high fluorescence response for UO2 2+ monitoring. The biosensor is ultrasensitive, with a detection limit of 2 pM. This sensing system also displays an excellent selectivity and robustness, enabling the DNA network biosensor to work even in complex water and soil samples with excellent accuracy and reliability. With the advantages of enzyme-free operation, outstanding specificity, and high sensitivity, our proposed DNA network biosensor provides a reliable, simple, and robust method for trace levels of UO2 2+ detection in environmental samples.
Polymer dielectrics, with advanced dielectric properties and heat resistance, are critical for high‐temperature capacitors in various applications. However, the high performance of heat resistance ...and dielectric properties are quite difficult to achieve all together due to their mutual implication. Here, by intensively investigating the correlation between molecular structure and properties, polyimide dielectrics with i) enhanced dielectric constant by introducing sulfonyl group, ii) low dissipation factor by introducing flexible linkage, and iii) high Tg
(glass transition temperature) by retaining an aromatic structure, are obtained. The sulfonyl‐containing polyimides with different flexible linkages exhibit simultaneously a high dielectric constant (4.50–5.98), low dissipation factor (0.00298–0.00426), and outstanding breakdown strength (most above 500 MV m−1), as well as superior heat resistance (Tg
: 244–304 °C). Specifically, the polyimide (SPI‐1) with sulfonyl group in diamine moiety and para‐para linkage shows stable dielectric properties up to 150 °C, and the discharged energy density and charge–discharge efficiency can be as high as 7.04 J cm−3 and 91.3% at 500 MV m−1, respectively.
A series of sulfonyl‐containing aromatic polyimide dielectrics is prepared through molecular tailoring. The dielectrics exhibit high dielectric constant, low dissipation factor, and excellent breakdown strength, as well as outstanding heat resistance simultaneously. The correlation between molecular structure and properties is investigated.
Despite recent transport studies of ABC-stacked multilayer graphene systems revealed various unusual quantum phenomena which arise from the nearly flat electronic bands, their quantum tunneling ...properties have rarely been addressed. Here we investigate the local tunneling characteristics of a gapped ABC-stacked trilayer graphene (TLG) and report the experimental observation of the nearly flat band induced atomic-site-dependent negative differential conductivity (NDC, characterized by a current drop with increasing voltage) via scanning tunneling spectroscopy (STS) measurements. We show that strong NDC emerges in the gap region next to a sharp STS peak induced by the very flat low-energy dispersion of ABC TLG. The NDC is found to mainly reside on one atomic sublattice of the surface layer due to the strong sublattice and layer localization of the nearly flat bands. The observed NDC behavior is explained by the tunnel-diode mechanism, namely, the coexistence of a sharp flat-dispersion STS peak in which tunneling is strongly enhanced and a subsequent gap region in which tunneling is forbidden. Furthermore, we also find that a local defect could effectively switch off the NDC over a large spatial range. Our result highlights a quantum tunneling effect unique to the graphene-based nearly flat band system and expands the potential application scope of ABC TLG.
Near-infrared (NIR) light-emitting polymers are important because of their many civilian and military applications. The general strategy to design NIR-emissive conjugated polymers is to copolymerize ...an electron-donating unit and electron-accepting unit to design donor–acceptor-type copolymers. The resulting NIR-emissive copolymers suffer from low fluorescence efficiencies and wide fluorescence spectra. In this work, we report a series of organoboron-conjugated homopolymers with high quality NIR light emission. The repeating unit of these homopolymers is a double B←N-bridged bipyridine (BNBP) unit bearing diphenylether as a large steric hindrance. Because of the rigid backbone and small reorganization energy of BNBP, the organoboron homopolymers emit high-quality NIR light with the emission peak wavelength of ca. 750 nm, fluorescence quantum efficiency of ca. 0.7, and full width at half-maximum of ca. 50 nm. The application of these homopolymers as visible to NIR light converters in NIR organic light-emitting diodes has been demonstrated. This work indicates a new strategy of organoboron chemistry to develop narrow-band and bright NIR-emissive polymers for practical applications.
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