ABSTRACT
We discuss the fabrication procedure and device characteristics of ITO/Zn2TiO4/Pt resistive random-access memory (RRAM) at room temperature. Four different resistive states were obtained by applying different current compliances, all of which showed good retention characteristics with no obvious degradation and were individually distinguished after 10 000 s at a read voltage of 100 mV. The multilevel memory effect can be attributed to the combination of the radial growth of filaments and the formation of conductive filaments when applying different compliance current values during the set process. The set and reset voltages of the ITO/Zn2TiO4/Pt RRAM device were maintained within ±1 V. The device performed well at low operation voltages. The mechanisms of multilevel resistive switching characteristics were investigated to illustrate the multilevel carrier conduction phenomenon associated with Zn2TiO4-based RRAM devices. In this study, our group illustrated the application of zinc titanate (Zn2TiO4) in non-volatile memories for the first time.
ABSTRACT
AIM: To investigate the loci of adefovir dipivoxil (ADV)-induced resistance in hepatitis B virus (HBV) isolates and optimize the management of ADV-treated patients. METHODS: Between June 2008 and August 2010, a cross-sectional control study was conducted comprising 79 patients with chronic HBV infection-related liver disease who had been administered ADV monotherapy. Patients underwent liver imaging. Serum DNA extracts were analyzed for HBV DNA levels, genotypes, and serology markers, and deep sequencing of the HBV P gene was performed. RESULTS: ADV-resistant patients were found either with a single mutated locus, or with coexisting mutated loci. The most prevalent mutations were rtA181T, rtV214A, and rtN236T. Twenty-six patients had more than two mutated loci. The mutants were distributed among the patients without any significant affinity for gender, age, end-stage of liver disease, complications of non-alcoholic fatty liver disease, or HBV DNA levels. Patients with the rtA181T mutant were primarily infected with genotype C and e-antigen negative HBV, while patients with the rtN236T mutant were primarily infected by genotype B HBV (χ(2) = 6.004, 7.159; P = 0.023, 0.007). The duration of treatment with ADV was shorter in the single mutant group compared with the multi-mutant group (t = 2.426, P = 0.018). CONCLUSION: Drug-resistant HBV mutants are complex and diverse. Patients should receive the standard and first-line antiviral treatment, strictly comply with medication dosage, and avoid short-term withdrawal.
Subject(s)
Adenine/analogs & derivatives , Antiviral Agents/therapeutic use , Drug Resistance, Viral/genetics , Hepatitis B virus/drug effects , Hepatitis B, Chronic/drug therapy , Mutation , Organophosphonates/therapeutic use , Adenine/therapeutic use , Adult , Chi-Square Distribution , Cross-Sectional Studies , DNA Mutational Analysis , DNA, Viral/genetics , Diagnostic Imaging/methods , Female , Genotype , Hepatitis B virus/genetics , Hepatitis B, Chronic/diagnosis , Hepatitis B, Chronic/virology , High-Throughput Nucleotide Sequencing , Humans , Male , Middle Aged , Predictive Value of Tests , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
Not Abstract.
