Well‐aligned ZnO nanowires (NWs) with tunable n‐type conductivity are synthesized by introducing Ga2O3 as a dopant source in thermal evaporation. The crystallographic orientation of the NWs depends ...on the dopant content. Electrical transport property measurements on single nanowires verify that the resistivity of ZnO NWs can be controlled, with high reproducibility, by the Ga impurities.
We have utilized DC and AC transport measurements to measure the resistance and capacitance of thin films of conjugated oligophenyleneimine (OPI) molecules ranging from 1.5 to 7.5 nm in length. These ...films were synthesized on Au surfaces utilizing the imine condensation chemistry between terephthalaldehyde and 1,4-benzenediamine. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy yielded molecular tilt angles of 33–43°. To probe DC and AC transport, we employed Au–S–OPI//GaO x /EGaIn junctions having contact areas of 9.6 × 102 μm2 (109 nm2) and compared to previously reported DC results on the same OPI system obtained using Au–S–OPI//Au conducting probe atomic force microscopy (CP-AFM) junctions with 50 nm2 areas. We found that intensive observables agreed very well across the two junction platforms. Specifically, the EGaIn-based junctions showed: (i) a crossover from tunneling to hopping transport at molecular lengths near 4 nm; (ii) activated transport for wires >4 nm in length with an activation energy of 0.245 ± 0.008 eV for OPI-7; (iii) exponential dependence of conductance with molecular length with a decay constant β = 2.84 ± 0.18 nm–1 (DC) and 2.92 ± 0.13 nm–1 (AC) in the tunneling regime, and an apparent β = 1.01 ± 0.08 nm–1 (DC) and 0.99 ± 0.11 nm–1 (AC) in the hopping regime; (iv) previously unreported dielectric constant of 4.3 ± 0.2 along the OPI wires. However, the absolute resistances of Au–S–OPI//GaO x /EGaIn junctions were approximately 100 times higher than the corresponding CP-AFM junctions due to differences in metal–molecule contact resistances between the two platforms.
To improve our understanding of the chemical characteristics of aerosols transported from the Asian continent to the western North Pacific, an aerosol observation network has been established in ...Taiwan. From the measurements made during 2003–2005, it was found that the aerosol concentrations in the continental outflows were much higher than those of remote areas, evidently due to the long-range transport of air pollutants and dust from the Asian continent. Analysis on the chemical compositions of aerosols revealed that the Asian outflow aerosols underwent chemical transformation and, consequently, became more abundant in ammonium and nitrate when they mixed with air pollutants originating from Taiwan. The NH
4
+/SO
4
2− ratio in fine aerosols (PM2.5) increased from 1.55 at the Cape Fuguei, the northern tip of Taiwan, to 2.30 at Penghu, in the middle of the Taiwan Strait. The increased NH
4
+/SO
4
2− ratio implied that the acidity of the sulfate aerosols in Asian outflows was totally neutralized by ammonia as the aerosols traveled through the North Taiwan and its vicinity. In addition, the analysis indicated that the chlorine deficiency of sea salt aerosols was higher at the southern stations than at the Cape Fuguei. The chlorine deficiency was attributed to the heterogeneous reaction of NaCl and HNO
3(g), which means that the oxidation of SO
2 in sea spray droplets was inhibited. Moreover, uptake of secondary acids by the dust particles was observed. The results of this study suggested that the Asian outflow aerosols are important carriers of gaseous inorganic nitrogen species, particularly nitric acid and ammonia, in this region. Hence the atmospheric deposition of soluble inorganic nitrogen could become enhanced in the northern South China Sea, which is downwind of Taiwan during the periods of Asian winter monsoons.
p-Type surface conductivity is a uniquely important property of hydrogen-terminated diamond surfaces. In this work, we report similar surface-dominated electrical properties in silicon nanowires ...(SiNWs). Significantly, we demonstrate tunable and reversible transition of p+−p−i−n−n+ conductance in nominally intrinsic SiNWs via changing surface conditions, in sharp contrast to the only p-type conduction observed on diamond surfaces. On the basis of Si band energies and the electrochemical potentials of the ambient (pH value)-determined adsorbed aqueous layer, we propose an electron-transfer-dominated surface doping model, which can satisfactorily explain both diamond and silicon surface conductivity. The totality of our observations suggests that nanomaterials can be described as a core−shell structure due to their large surface-to-volume ratio. Consequently, controlling the surface or shell in the core−shell model represents a universal way to tune the properties of nanostructures, such as via surface-transfer doping, and is crucial for the development of nanostructure-based devices.
The association between the regular use of proton pump inhibitors (PPIs) and the risk of type 2 diabetes remains unclear, although a recent randomised controlled trial showed a trend towards ...increased risk. This study was undertaken to evaluate the regular use of PPIs and risk of type 2 diabetes.
This is a prospective analysis of 204 689 participants free of diabetes in the Nurses' Health Study (NHS), NHS II and Health Professionals Follow-up Study (HPFS). Type 2 diabetes was confirmed using American Diabetes Association (ADA) diagnostic criteria. We evaluated hazard ratios (HRs) adjusting for demographic factors, lifestyle habits, the presence of comorbidities, use of other medications and clinical indications.
We documented 10 105 incident cases of diabetes over 2 127 471 person-years of follow-up. Regular PPI users had a 24% higher risk of diabetes than non-users (HR 1.24, 95% CI 1.17 to 1.31). The risk of diabetes increased with duration of PPI use. Fully adjusted HRs were 1.05 (95% CI 0.93 to 1.19) for participants who used PPIs for >0-2 years and 1.26 (95% CI 1.18 to 1.35) for participants who used PPIs for >2 years compared with non-users.
Regular use of PPIs was associated with a higher risk of type 2 diabetes and the risk increased with longer duration of use. Physicians should therefore exercise caution when prescribing PPIs, particularly for long-term use.
Despite being one of the most promising candidates for grid‐level energy storage, practical aqueous zinc batteries are limited by dendrite formation, which leads to significantly compromised safety ...and cycling performance. In this study, by using single‐crystal Zn‐metal anodes, reversible electrodeposition of planar Zn with a high capacity of 8 mAh cm−2 can be achieved at an unprecedentedly high current density of 200 mA cm−2. This dendrite‐free electrode is well maintained even after prolonged cycling (>1200 cycles at 50 mA cm−2). Such excellent electrochemical performance is due to single‐crystal Zn suppressing the major sources of defect generation during electroplating and heavily favoring planar deposition morphologies. As so few defect sites form, including those that would normally be found along grain boundaries or to accommodate lattice mismatch, there is little opportunity for dendritic structures to nucleate, even under extreme plating rates. This scarcity of defects is in part due to perfect atomic‐stitching between merging Zn islands, ensuring no defective shallow‐angle grain boundaries are formed and thus removing a significant source of non‐planar Zn nucleation. It is demonstrated that an ideal high‐rate Zn anode should offer perfect lattice matching as this facilitates planar epitaxial Zn growth and minimizes the formation of any defective regions.
Zinc‐metal anodes, which are desirable for various aqueous zinc battery chemistries, degrade over repeated cycling due to dendrite growth. It is found that dendrites can be prevented by ensuring no defective regions form during zinc deposition, thus removing sites for dendrite nucleation and ensuring purely planar deposition. This allows unprecedentedly high charging rates to be achieved.
We examined the global incidence and mortality rates of liver cancer, and evaluated the association between incidence/mortality and socioeconomic development (Human Development Index HDI and Gross ...Domestic Product GDP) using linear regression analysis. The average annual percent change (AAPC) of the trends was evaluated from join-point regression analysis. The global incidence of liver cancer varied widely by nine-fold, and was negatively correlated with HDI (men: r = -0.232, p = 0.003; women: r = -0.369, p < 0.001) and GDP per capita (men: r = -0.164, p = 0.036; women: r = -0.212, p = 0.007). Its mortality showed a similarly negative correlation with both indices. The greatest incidence rise in men was observed in Poland (AAPC = 17.5, 95% C.I. = 5.6, 30.9) and Brazil (AAPC = 13.2, 95% C.I. = 5.9, 21.0), whereas Germany (AAPC = 6.6, 95% C.I = 2.0, 11.5) and Norway (AAPC = 6.5, 95% C.I. = 3.2, 10.0) had the greatest increase in women. The mortality rates paralleled the incidence rates in most countries. For mortality, Malta (AAPC = 11.5, 95% C.I. = 3.9, 19.8), Australia (AAPC = 6.8, 95% C.I. = 2.2, 11.5) and Norway (APCC = 5.6, 95% C.I. = 2.8, 8.5) reported the biggest increase among men; whilst Australia (AAPC = 13.4, 95% C.I. = 7.8, 19.4) and Singapore (AAPC = 7.7, 95% C.I. = 4.1, 11.5) showed the most prominent rise among women. These epidemiological data identified countries with potentially increasing trends of liver cancer for preventive actions.
Purpose Selective internal radiation therapy or radioembolization (RE) shows efficacy in unresectable hepatocellular carcinoma (HCC) limited to the liver. This study compared the safety and efficacy ...of RE and sorafenib in patients with locally advanced HCC. Patients and Methods SIRveNIB (selective internal radiation therapy v sorafenib), an open-label, investigator-initiated, phase III trial, compared yttrium-90 (
Y) resin microspheres RE with sorafenib 800 mg/d in patients with locally advanced HCC in a two-tailed study designed for superiority/detriment. Patients were randomly assigned 1:1 and stratified by center and presence of portal vein thrombosis. Primary end point was overall survival (OS). Efficacy analyses were performed in the intention-to-treat population and safety analyses in the treated population. Results A total of 360 patients were randomly assigned (RE, 182; sorafenib, 178) from 11 countries in the Asia-Pacific region. In the RE and sorafenib groups, 28.6% and 9.0%, respectively, failed to receive assigned therapy without significant cross-over to either group. Median OS was 8.8 and 10.0 months with RE and sorafenib, respectively (hazard ratio, 1.1; 95% CI, 0.9 to 1.4; P = .36). A total of 1,468 treatment-emergent adverse events (AEs) were reported (RE, 437; sorafenib, 1,031). Significantly fewer patients in the RE than sorafenib group had grade ≥ 3 AEs (36 of 130 27.7%) v 82 of 162 50.6%; P < .001). The most common grade ≥ 3 AEs were ascites (five of 130 3.8% v four of 162 2.5% patients), abdominal pain (three 2.3% v two 1.2% patients), anemia (zero v four 2.5% patients), and radiation hepatitis (two 1.5% v zero 0% patients). Fewer patients in the RE group (27 of 130 20.8%) than in the sorafenib group (57 of 162 35.2%) had serious AEs. Conclusion In patients with locally advanced HCC, OS did not differ significantly between RE and sorafenib. The improved toxicity profile of RE may inform treatment choice in selected patients.
State-of-the-art n-i-p perovskite solar cells (PSCs) suffer from stability issues due to ionic interdiffusion. Herein, by enlarging the indacenodithiophene π-bridge donor (D′) to combine with the ...methoxy triphenylamine donor (D) and benzothiadiazole acceptor (A), three linear molecules termed L1, L2 and L3 with a D-A-D′-A-D structure are developed as dopant-free hole transport materials (HTMs). The π-bridge extension with active sites for coordination leverages the intramolecular dipole effect and intermolecular packing effect, resulting in a conformally bonded ultrathin interface with compact and uniform coverage (∼60 nm) to retard iodine migration and protect the buried perovskite. The unencapsulated L3-PSC (ITO/SnO
2
/perovskite/L3/MoO
3
/Au) achieved an impressive PCE of 22.61% (certified 21.79%, 0.0525 cm
2
). Ultrafast laser spectroscopy reveals that L-series molecules have a sequential reduction of photoexcited energy disorder to illustrate the structure-performance-stability relationship. L3-PSC maintains over 85% of the initial efficiency after 500 h at 85 °C maximum power point tracking (MPP) and enables the possibility of using small molecules to stabilize n-i-p PSCs.
A molecular hole transport material retards the iodine migration and delivers high stability in a harsh 85 °C MPP test.
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