2D fin field-effect transistors integrated with epitaxial high-k gate oxide.

Precise integration of two-dimensional (2D) semiconductors and high-dielectric-constant (k) gate oxides into three-dimensional (3D) vertical-architecture arrays holds promise for developing ultrascaled transistors1-5, but has proved challenging. Here we report the epitaxial synthesis of vertically aligned arrays of 2D fin-oxide heterostructures, a new class of 3D architecture in which high-mobility 2D semiconductor fin Bi2O2Se and single-crystal high-k gate oxide Bi2SeO5 are epitaxially integrated. These 2D fin-oxide epitaxial heterostructures have atomically flat interfaces and ultrathin fin thickness down to one unit cell (1.2 nm), achieving wafer-scale, site-specific and high-density growth of mono-oriented arrays. The as-fabricated 2D fin field-effect transistors (FinFETs) based on Bi2O2Se/Bi2SeO5 epitaxial heterostructures exhibit high electron mobility (µ) up to 270 cm2 V-1 s-1, ultralow off-state current (IOFF) down to about 1 pA µm-1, high on/off current ratios (ION/IOFF) up to 108 and high on-state current (ION) up to 830 µA µm-1 at 400-nm channel length, which meet the low-power specifications projected by the International Roadmap for Devices and Systems (IRDS)6. The 2D fin-oxide epitaxial heterostructures open up new avenues for the further extension of Moore's law.

Strain-Free Layered Semiconductors for 2D Transistors with On-State Current Density Exceeding 1.3 mA µm-1.

High-mobility and air-stable two-dimensional (2D) Bi2O2Se semiconductor holds promise as an alternative fast channel material for next-generation transistors. However, one of the key challenges remaining in 2D Bi2O2Se is to prepare high-quality crystals to fabricate the high-performance transistors with a high on-state current density. Here, we present the free-standing growth of strain-free 2D Bi2O2Se crystals. An ultrahigh Hall mobility of 160 000 cm2 V-1 s-1 is measured in strain-free Bi2O2Se crystals at 2 K, which enables the observation of Shubnikov-de Haas quantum oscillations and shows substantially higher (>4 times) mobility over previous in-plane 2D crystals. The fabricated 2D transistors feature an on-off current ratio of ∼106 and a record-high on-state current density of ∼1.33 mA µm-1, which is comparable to that of commercial Si and Ge n-type field-effect transistors (FETs) for similar channel length. Strain-free 2D Bi2O2Se provides a promising material platform for studying novel quantum phenomena and exploration of high-performance low-power electronics.

Integrated 2D multi-fin field-effect transistors.

Vertical semiconducting fins integrated with high-κ oxide dielectrics have been at the centre of the key device architecture that has promoted advanced transistor scaling during the last decades. Single-fin channels based on two-dimensional (2D) semiconductors are expected to offer unique advantages in achieving sub-1 nm fin-width and atomically flat interfaces, resulting in superior performance and potentially high-density integration. However, multi-fin structures integrated with high-κ dielectrics are commonly required to achieve higher electrical performance and integration density. Here we report a ledge-guided epitaxy strategy for growing high-density, mono-oriented 2D Bi2O2Se fin arrays that can be used to fabricate integrated 2D multi-fin field-effect transistors. Aligned substrate steps enabled precise control of both nucleation sites and orientation of 2D fin arrays. Multi-channel 2D fin field-effect transistors based on epitaxially integrated 2D Bi2O2Se/Bi2SeO5 fin-oxide heterostructures were fabricated, exhibiting an on/off current ratio greater than 106, high on-state current, low off-state current, and high durability. 2D multi-fin channel arrays integrated with high-κ oxide dielectrics offer a strategy to improve the device performance and integration density in ultrascaled 2D electronics.

Epidemiological investigation of Entamoeba in wild rhesus macaques in China: A novel ribosomal lineage and genetic differentiation of Entamoeba nuttalli.

Wild rhesus macaques are a potential source of zoonotic parasites for humans, and Entamoeba spp. are common intestinal parasites. To investigate the prevalence of Entamoeba in wild rhesus macaques in China and explore the genetic differentiation of the potentially pathogenic species Entamoeba nuttalli, a total of 276 fecal samples from five populations at high altitudes (HAG, 2,800-4,100 m above sea level) and four populations at low altitudes (LAG, 5-1,000 m above sea level) were collected. PCR methods based on the ssrRNA gene were used to detect Entamoeba infection. Genotyping of E. nuttalli was performed based on six tRNA-linked short tandem repeat (STR) loci for further genetic analyses. The results revealed that Entamoeba infection (69.2%) was common in wild rhesus macaques in China, especially in LAG which had a significantly higher prevalence rate than that in HAG (P < 0.001). Three zoonotic species were identified: Entamoeba chattoni (60.9%) was the most prevalent species and distributed in all the populations, followed by Entamoeba coli (33.3%) and Entamoeba nuttalli (17.4%). In addition, a novel Entamoeba ribosomal lineage named RL13 (22.8%) was identified, and phylogenetic analysis revealed a close genetic relationship between RL13 and Entamoeba. hartmanni. Genotyping of E. nuttalli obtained 24 genotypes from five populations and further analysis showed E. nuttalli had a high degree of genetic differentiation (FST > 0.25, Nm < 1) between the host populations. The result of analysis of molecular variance (AMOVA) revealed that observed genetic differences mainly originate from differences among populations (FST = 0.91). Meanwhile, the phylogenetic tree showed that these genotypes of E. nuttalli were clustered according to geographical populations, indicating a significant phylogeographic distribution pattern. Considering the potential pathogenicity of E. nuttalli, attention should be paid to its risk of zoonotic transmission.

Metabarcoding of protozoa and helminth in black-necked cranes: a high prevalence of parasites and free-living amoebae.

Parasites and free-living amoebae (FLA) are common pathogens that pose threats to wildlife and humans. The black-necked crane (Grus nigricollis) is a near-threatened species and there is a shortage of research on its parasite diversity. Our study aimed to use noninvasive methods to detect intestinal parasites and pathogenic FLA in G. nigricollis using high-throughput sequencing (HTS) based on the 18S rDNA V9 region. A total of 38 fresh fecal samples were collected in Dashanbao, China, during the overwintering period (early-, middle I-, middle II-, and late-winter). Based on the 18S data, eight genera of parasites were identified, including three protozoan parasites: Eimeria sp. (92.1%) was the dominant parasite, followed by Tetratrichomonas sp. (36.8%) and Theileria sp. (2.6%). Five genera of helminths were found: Echinostoma sp. (100%), Posthodiplostomum sp. (50.0%), Euryhelmis sp. (26.3%), Eucoleus sp. (50.0%), and Halomonhystera sp. (2.6%). Additionally, eight genera of FLA were detected, including the known pathogens Acanthamoeba spp. (n = 13) and Allovahlkampfia spp. (n = 3). Specific PCRs were used to further identify the species of some parasites and FLA. Furthermore, the 18S data indicated significant changes in the relative abundance and genus diversity of the protozoan parasites and FLA among the four periods. These results underscore the importance of long-term monitoring of pathogens in black-necked cranes to protect this near-endangered species.

Title: Métabarcoding des protozoaires et des helminthes chez les grues à cou noir : forte prévalence de parasites et d'amibes libres. Abstract: Les parasites et les amibes libres sont des agents pathogènes courants qui constituent une menace pour la faune et les humains. La grue à cou noir (Grus nigricollis) est une espèce quasi menacée et les recherches sur sa diversité parasitaire sont insuffisantes. Notre étude visait à utiliser des méthodes non invasives pour détecter les parasites intestinaux et les amibes libres pathogènes chez G. nigricollis en utilisant le séquençage à haut débit basé sur la région V9 de l'ADNr 18S. Au total, 38 échantillons de matières fécales fraîches ont été collectés à Dashanbao, en Chine, au cours de la période d'hivernage (début, milieu I, milieu II et fin de l'hiver). Sur la base des données 18S, huit genres de parasites ont été identifiés, dont trois parasites protozoaires : Eimeria sp. (92,1 %) était le parasite dominant, suivi de Tetratrichomonas sp. (36,8 %) et Theileria sp. (2,6 %). Cinq genres d'helminthes ont été trouvés : Echinostoma sp. (100 %), Posthodiplostomum sp. (50,0 %), Euryhelmis sp. (26,3 %), Eucoleus sp. (50,0 %) et Halomonhystera sp. (2,6 %). De plus, huit genres d'amibes libres ont été détectés, y compris les agents pathogènes connus Acanthamoeba spp. (n = 13) et Allovahlkampfia spp. (n = 3). Des PCR spécifiques ont été utilisées pour identifier davantage les espèces de certains parasites et amibes libres. En outre, les données 18S ont indiqué des changements significatifs dans l'abondance relative et la diversité des genres des parasites protozoaires et des amibes au cours des quatre périodes. Ces résultats soulignent l'importance de la surveillance à long terme des agents pathogènes chez les grues à cou noir pour protéger cette espèce quasi menacée.

Extensive prevalence and significant genetic differentiation of Blastocystis in high- and low-altitude populations of wild rhesus macaques in China.

BACKGROUND: Blastocystis is a common intestinal protist with a wide range of hosts. Thus far, 38 subtypes have been identified. In recent years, wild animals have been confronted with habitat fragmentation as well as an increasing risk of zoonotic disease transmission due to human disturbance. Only limited data are available on Blastocystis infection and subtype distribution in wild rhesus macaques in China. The aim of the present study was to investigate the prevalence and genetic diversity of Blastocystis in nine wild rhesus macaque populations in China. METHODS: A total of 276 faecal samples were collected from five high-altitude populations (high-altitude group [HAG]; 2800-4100 m a.s.l.) and four low-altitude populations (low-altitude group [LAG]; 5-1000 m a.s.l) of rhesus macaques. PCR-based analysis, using a new primer pair for the amplification of a 1690-bp sequence of the small subunit ribosomal RNA (SSU rRNA) gene, was used for prevalence and genetic diversity analysis. RESULT: Analysis of faecal samples revealed that Blastocystis infection was common in rhesus macaques, with an infection positivity rate of 80.1% (n = 221/276 samples). There was no significant difference (P = 0.121) in positivity rate between the LAG (84.3%) and HAG (76.8%). Overall, 33 haplotypes were obtained and classified into four subtypes (STs), of which three were potentially zoonotic subtypes (ST1, 29.7%; ST2, 16.7%; ST3, 31.9%) and one that was first identified in this study and named ST39 (12.0%). The STs were distributed differently among the rhesus macaque populations, except for ST3, which was found in all populations. Phylogenetic analyses revealed two major divergent clades of ST3 for the HAG and LAG. Genetic diversity analysis showed a high genetic diversity of ST3 (haplotype diversity: 0.846; nucleotide diversity: 0.014) in the rhesus macaques, but a high genetic differentiation (FST > 0.25) and a low gene flow (Nm = 0.09) between the HAG and LAG. CONCLUSION: Our study, which is the first investigation on Blastocystis infection in multiple wild rhesus macaque populations in China, indicates a potential risk of zoonotic transmission of Blastocystis in the study areas. Blastocystis ST3 showed high genetic diversity in wild rhesus macaques and significant genetic differentiation between the HAG and LAG. Our results provide fundamental information on the genetic diversity and prevalence of Blastocystis in wild rhesus macaque populations.

Upconversion nanoparticles coupled with hierarchical ZnIn2S4 nanorods as a near-infrared responsive photocatalyst for photocatalytic CO2 reduction.

Developing near-infrared responsive (NIR) photocatalysts is very important for the development of solar-driven photocatalytic systems. Metal sulfide semiconductors have been extensively used as visible-light responsive photocatalysts for photocatalytic applications owing to their high chemical variety, narrow bandgap and suitable redox potentials, particularly the benchmark ZnIn2S4. However, their potential as NIR-responsive photocatalysts is yet to be reported. Herein, for the first time demonstrated that upconversion nanoparticles can be delicately coupled with hierarchical ZnIn2S4 nanorods (UCNPs/ZIS) to assemble a NIR-responsive composite photocatalyst, and as such composite is verified by ultraviolet-visible diffuse reflectance spectra and upconversion luminescence spectra. As a result, remarkable photocatalytic CO and CH4 production rates of 1500 and 220 nmol g-1h-1, respectively, were detected for the UCNPs/ZIS composite under NIR-light irradiation (λ ≥ 800 nm), which is rarely reported in the literature. The remarkable photocatalytic activity of the UCNPs/ZIS composite can be understood not only because the heterojunction between UCNPs and ZIS can promote the charge separation efficiency, but also the intimate interaction of UCNPs with hierarchical ZIS nanorods can enhance the energy transfer. This finding may open a new avenue to develop more NIR-responsive photocatalysts for various solar energy conversion applications.

Prevalence and new genotypes of Enterocytozoon bieneusi in wild rhesus macaque (Macaca mulatta) in China: A zoonotic concern.

Enterocytozoon bieneusi is a zoonotic pathogen with a wide range of animal host. There are only few reports of E. bieneusi infection in wild Chinese rhesus macaques. Here, we determined the prevalence of E. bieneusi in nine wild rhesus macaque populations and assessed their zoonotic potential by performed genotype of ITS gene. A total of 324 fecal samples of rhesus macaque were collected in nine geographical populations from five Chinese provinces (Sichuan, Chongqing, Qinghai, Tibet and Hainan). 38 samples (11.7%) were found to be infected with E. bieneusi, and 11 genotypes were identified including three known genotypes (D, EbpC and SCC-2) and eight novel genotypes named Mul6∼13. Genotype D (63.2%) was the most prevalent, being observed in seven populations except XZ-2 and QH, and other genotypes were identified only in a single area. According to the phylogenetic analysis, Mul6∼9, Mul11∼13 and zoonotic genotype D were clustered into Group 1, indicating that these genotypes may be potentially zoonotic. Among nine populations, population SC-3 had the highest infection rate (26.3%), and the lowest was the wild QH population without infection, but the difference of infection rate among the nine populations is not significant. It is concluded that, rhesus macaque populations are generally infected E. bieneusi in many areas of China, and there may be a risk of cross infection with E. bieneusi in some areas found having zoonotic genotypes, and these areas should be paid more attention to prevent.

MOF-derived synthesis of MnS/In2S3p-n heterojunctions with hierarchical structures for efficient photocatalytic CO2 reduction.

Photoreduction of CO2 to valuable fuels with semiconductor photocatalysts is a good solution to the problems of global warming and energy crisis. Creation of hybrid nanomaterials with hierarchical and/or heterojunction structures is beneficial to develop efficient photocatalysts for CO2 reduction. Herein we present a convenient method to obtain a hybrid photocatalyst consisting of MnS and In2S3 nanosheets with assembled hierarchical structures through using Mn2+-loaded MIL-68(In) submicro-rods as templates. Owing to the dispersive Mn2+ and In3+ ions in templates, numerous small p-n heterojunctions of MnS/In2S3 could be simultaneously produced in each hierarchical particle. The p-type MnS and n-type In2S3 with an original type II band alignment can create a stronger built-in electric field after the formation of p-n heterojunctions, which is favorable for charge separation and migration to catalyst surface. The prepared MnS/In2S3 heterojunctions show an 4-fold higher photocatalytic activity toward CO2 reduction than pristine MnS and In2S3. The MnS/In2S3 hierarchical structures were well characterized and their working mechanism was explored. This work demonstrates a facile strategy to create efficient hybrid photocatalysts with both hierarchical structures and p-n heterojunctions for photocatalytic applications.

Epidemiological investigation and genotypes of Enterocytozoon bieneusi in 11 captive Rhesus macaque populations.

Enterocytozoon bieneusi is an obligate intracellular parasite and the most common pathogen of microsporidiosis in humans and animals. In this study, a total of 198 fecal samples were collected from 11 captive populations of Rhesus macaque in Chinese zoos, to investigate the prevalence and analyze the zoonotic potential of E. bieneusi by genotype of the Internal Transcribed Spacer (ITS) gene on the rRNA of E. bieneusi via nested PCR. Results showed that the average infection rate of E. bieneusi in the 11 populations was 13.6%, and the highest infection rate was 56.5% in the population of Xinjiang Tianshan Zoo. Seven genotypes were identified including 2 known genotypes (D and CM1) and 5 novel genotypes (Mul1, Mul2, Mul3, Mul4 and Mul5). Phylogenetic analysis revealed that the novel genotypes Mul2, Mul3, Mul4 and Mul5 belonged to Group 1 showed the zoonotic potential．These findings extend the distribution of E. bieneusi genotypes and provide baseline data for controlling E. bieneusi infection.

The complete mitochondrial genome sequence and phylogenetic analysis of yellow weasel (Mustela sibirica).

In this study, we determined the complete mitochondrial genome sequence of the Mustela sibirica. The complete mitogenome of M. sibirica is 16,529 bp in length and consist of 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a D-loop region. The overall base composition of the mitochondrial DNA is 32.88%A, 13.84%G, 27.32%T, and 25.96%C. The phylogenetic tree of the family Mustelidae constructed by using mitogenome sequences from 10 mustelid species of the family Mustelidae. These results provide necessary information for molecular phylogeny and evolutionary analysis of the M. sibirica.