The authors conducted a study to assess the importance of underlying liver cirrhosis in the development of hepatocellular carcinoma (HCC) and the multifactorial etiology of liver cirrhosis in chronic carriers of hepatitis B virus (HBV). Between November 1980 and May 1990, all male hepatitis B surface antigen (HBsAg) carriers who routinely attended a clinic for asymptomatic HBV carriers at the Liver Unit of Chang-Gung Memorial Hospital, Taiwan, were enrolled in the study (n = 1,506). The authors used this cohort to investigate prospectively for liver cirrhosis and HCC at 6-month intervals by means of ultrasonography and clinical assessment. There were 16 incident cases of HCC and 89 cases of liver cirrhosis (78 of whom were detected during follow-up) identified after an average follow-up of 7.1 years. Subclinical liver cirrhosis diagnosed by ultrasonography was significantly associated with the risk for HCC (multivariate-adjusted relative risk (RR) = 11.8, 95% confidence interval (CI) 3.9-35.8). By multivariate analysis, the significant risk factors found for liver cirrhosis in HBsAg carriers were age, hepatitis B e antigen (HBeAg) carrier status, chronic hepatitis manifested by sustained elevated serum aminotransferase levels for > or = 6 months, cigarette smoking, non-A blood types, and low educational levels. Habitual alcohol drinking was not independently related to liver cirrhosis. However, the risk of liver cirrhosis associated with smoking was more striking among drinkers than nondrinkers (> or = 20 cigarettes/day vs. nonsmokers: drinkers, RR = 9.3, 95% CI 1.1-78.8; nondrinkers, RR = 1.85, 95% CI 0.98-3.51), which suggests a possible modification effect of alcohol drinking on the liver cirrhosis risk of cigarette smoking. The authors observed synergistic effects on liver cirrhosis development for cigarette smoking with HBeAg carrier status and chronic hepatitis.

No abstract

A newly designed transferable and flexible label-like organic memory based on a graphene electrode behaves like a sticker, and can be readily placed on desired substrates or devices for diversified purposes. The memory label reveals excellent performance despite its physical presentation. This may greatly extend the memory applications in various advanced electronics and provide a simple scheme to integrate with other electronics.

The trend towards simple and low-cost processing is one of the most important for macromolecular memory development. Here, bistable memory devices using a solution-processable active material, a mixture of graphene nanoflakes (GNFs) and insulating poly(vinyl alcohol) (PVA), are investigated, which serve as the first example for the direct integration of as-prepared nanoscale graphene into macromolecular memory devices through a one-step low-temperature processing method. Bistable electrical switching behavior and nonvolatile rewritable memory effects are realized by using an indium-tin-oxide/GNF-PVA/silver (ITO/GNF-PVA/Ag) sandwich structure. The resulting device exhibits low operation voltages of +1.4 V (turn-on) and À1.3 V (turn-off), which is promising for memory cells with low power consumptions. The programmable ON-and OFF-states possess a retention time of over 10 4 s and endure up to 10 7 read pulses. The carrier transport in the OFF-and ON-states follows the typical trap-limited space charge limited current and Ohmic laws, respectively. The asymmetric electrical switch behavior is therefore attributed to conducting filaments formed in the PVA layer assisted by the charged GNFs that induce the transition of the conductivity. Our study provides a potential approach for integrating as-prepared graphene into macromolecular memory devices with excellent performances through a simple solution-process.

A new approach to largely enhancing light harvesting of solar cells by employing bifunctional polymer nanocomposites as hole-transport layers (HTLs) is proposed. To illustrate our working principle, CH3NH3PbI3-xClx perovskite solar cells are used as examples. Gold nanoparticles (Au-NPs) are added into a conjugated poly(3-hexylthiophene-2,5-diyl) (P3HT) matrix, resulting in a ∼4-fold enhancement in the electrical conductivity and carrier mobility of the native P3HT film. The improved electrical properties are attributed to enhanced polymer chain ordering caused by Au-NPs. By integration of those P3HT:Au-NP films with an optimum loading concentration of 20% into perovskite solar cells as HTLs, this leads to a more than 25% enhancement in the power conversion efficiency (PCE) compared with that of the NP-free one. In addition to the modulated electrical properties of the HTL, the improved performance can also be attributed to the scattering effect from the incorporated Au-NPs, which effectively extends the optical pathway to amplify photon absorption of the photoactive layer. The design principle shown here can be generalized to other organic materials as well, which should be very useful for the further development of high-performance optoelectronic devices.