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As demand for higher integration density and smaller devices grows, silicon-based complementary metal-oxide-semiconductor (CMOS) devices will soon reach their ultimate limits. 2D transition metal dichalcogenides (TMDs) semiconductors, known for excellent electrical performance and stable atomic structure, are seen as promising materials for future integrated circuits. However, controlled and reliable doping of 2D TMDs, a key step for creating homogeneous CMOS logic components, remains a challenge. In this study, a continuous electrical polarity modulation of monolayer WS2 from intrinsic n-type to ambipolar, then to p-type, and ultimately to a quasi-metallic state is achieved simply by introducing controllable amounts of vanadium (V) atoms into the WS2 lattice as p-type dopants during chemical vapor deposition (CVD). The achievement of purely p-type field-effect transistors (FETs) is particularly noteworthy based on the 4.7 at% V-doped monolayer WS2, demonstrating a remarkable on/off current ratio of 105. Expanding on this triumph, the first initial prototype of ultrathin homogeneous CMOS inverters based on monolayer WS2 is being constructed. These outcomes validate the feasibility of constructing homogeneous CMOS devices through the atomic doping process of 2D materials, marking a significant milestone for the future development of integrated circuits.
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Visuomorphic computing aims to simulate and potentially surpass the human retina by mimicking biological visual perception with an artificial retina. Despite significant progress, challenges persist in perceiving complex interactive environments. Negative photoconductivity transistors (NPTs) mimic synaptic behavior by achieving adjustable positive photoconductivity (PPC) and negative photoconductivity (NPC), simulating "excitation" and "inhibition" akin to sensory cell signals. In complex interactive environments, NPTs are desired for visuomorphic computing that can achieve a better sense of information, lower power consumption, and reduce hardware complexity. In this review, it is started by introducing the development process of NPTs, while placing a strong emphasis on the device structures, working mechanisms, and key performance parameters. The common material systems employed in NPTs based on their functions are then summarized. Moreover, it is proceeded to summarize the noteworthy applications of NPTs in optoelectronic devices, including advanced multibit nonvolatile memory, optoelectronic logic gates, optical encryption, and visual perception. Finally, the challenges and prospects that lie ahead in the ongoing development of NPTs are addressed, offering valuable insights into their applications in optoelectronics and a comprehensive understanding of their significance.
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Inorganic semiconductors typically have limited p-type behavior due to the scarcity of holes and the localized valence band maximum, hindering the progress of complementary devices and circuits. In this work, we propose an inorganic blending strategy to activate the hole-transporting character in an inorganic semiconductor compound, namely tellurium-selenium-oxygen (TeSeO). By rationally combining intrinsic p-type semimetal, semiconductor, and wide-bandgap semiconductor into a single compound, the TeSeO system displays tunable bandgaps ranging from 0.7 to 2.2 eV. Wafer-scale ultrathin TeSeO films, which can be deposited at room temperature, display high hole field-effect mobility of 48.5 cm2/(Vs) and robust hole transport properties, facilitated by Te-Te (Se) portions and O-Te-O portions, respectively. The nanosphere lithography process is employed to create nanopatterned honeycomb TeSeO broadband photodetectors, demonstrating a high responsibility of 603 A/W, an ultrafast response of 5 µs, and superior mechanical flexibility. The p-type TeSeO system is highly adaptable, scalable, and reliable, which can address emerging technological needs that current semiconductor solutions may not fulfill.
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<p><b>BACKGROUND</b>There were some papers published in the Jonrnal of Science, December 2000 suggesting that one or more important susceptibility genes for late onset Alzheimer's disease (LOAD) were located on the long arm of chromosome 10. Linkage analysis showed maximum lod score close to D10S1225 loci, which indicated the loci might contribute to the etiology of Alzheimer's disease (AD).</p><p><b>METHODS</b>Fifty-nine LOAD patients and 107 controls were recruited. Apolipoprotein E (ApoE) genotypes were determined by reverse dot blotting hybridization assay. The D10S1225 was genotyped by 12% nondenaturing polyacrylamide gels electrophoresis and analyzed by silver staining. Statistical analysis was used to compare genotype and allele distributions between LOAD group and control group for ApoE and D10S1225 polymorphisms.</p><p><b>RESULTS</b>ApoE epsilon 4 was significantly higher in LOAD group in comparison with the control group (chi(2) = 6.530, P = 0.011). Seven different alleles of D10S1225 have been identified. The length of these gene fragments were 178 bp, 181 bp, 184 bp, 187 bp, 190 bp, 193 bp, and 196 bp, respectively. A total of 21 different genotypes were observed. There was no relationship between D10S1225 polymorphism and LOAD (chi(2) = 4.488, P > 0.05). Conclusion This study suggests that ApoE epsilon 4 is a risk factor for LOAD, however, the results indicated that there is not any possible linkage for disequilibria with a nearby AD risk gene near D10S1225.</p>
Asunto(s)
Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Alelos , Enfermedad de Alzheimer , Genética , Apolipoproteínas E , Genética , Genotipo , Desequilibrio de Ligamiento , Polimorfismo GenéticoRESUMEN
<p><b>OBJECTIVE</b>To determine the molecular basis of late onset ornithine transcarbamylase (OTC) deficiency in a Chinese family of Han nationality and the exon sequences of OTC gene of this patient.</p><p><b>METHODS</b>Polymerase chain reaction-single strand conformation polymorphism and direct sequencing were used to identify the mutation type.</p><p><b>RESULTS</b>A missense mutation E122G in the conserved residue of exon 4 was identified which is unreported before.</p><p><b>CONCLUSION</b>The E122G mutation in human OTC gene may cause late onset OTC deficiency.</p>
Asunto(s)
Preescolar , Femenino , Humanos , Masculino , Edad de Inicio , Secuencia de Bases , ADN , Química , Genética , Análisis Mutacional de ADN , Salud de la Familia , Resultado Fatal , Modelos Moleculares , Mutación Missense , Ornitina Carbamoiltransferasa , Química , Genética , Enfermedad por Deficiencia de Ornitina Carbamoiltransferasa , Genética , Patología , Linaje , Polimorfismo Conformacional Retorcido-Simple , Estructura Secundaria de ProteínaRESUMEN
<p><b>OBJECTIVE</b>To explore new mutation in phenylalanine hydroxylase (PAH) gene.</p><p><b>METHODS</b>The PAH genes from 40 phenylketonuria (PKU) patients and 30 normal controls were screened by PCR-single strand conformation polymorphism (SSCP) and further sequencing.</p><p><b>RESULTS</b>Eleven mutations and 3 polymorphisms in PAH gene were found. No abnormalities in the PAH gene from 30 controls were detected.</p><p><b>CONCLUSION</b>M276K, M276R, 280insT, IVS10nt+32T-->A, IVS4nt+47C-->T were demonstrated as novel mutations in comparison with the PAH mutation database. One mission mutation (H290R) was first documented in Chinese PKU gene.</p>