A superconducting interfaceInterfaces between materials can harbor quantum states that belong to neither of the materials. A classic example is the superconducting interface between two insulating ...oxides, LaAlO3 and SrTiO3, with a critical temperature of around 200 millikelvin. Liu et al. observed superconductivity at a different interface—formed between KTaO3 as a substrate and an overlayer of either EuO or LaAlO3—at a considerably higher temperature of about 2 kelvin. Transport measurements displayed anisotropy, which may indicate an unusual superconducting state.Science, this issue p. 716The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. Here we report on the discovery of superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3. The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Notably, similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicate that the superconductivity is two-dimensional. In EuO/KTaO3 (111) samples, a spontaneous in-plane transport anisotropy is observed before the onset of superconductivity, suggesting the emergence of a distinct “stripe”-like phase, which is also revealed near the critical field.
The sequenced Diels-Alder/oxidation reaction represents a powerful route for the construction of aromatic compounds in organic synthesis. The oxidative Diels-Alder reaction with H
evolution would be ...a more ideal approach that can avoid the additional oxidation procedure and stoichiometric oxidant. Herein, an oxidative 4 + 2 annulation reaction of styrene derivatives with electron-rich dienophiles accompanying the H
generation has been developed by using the synergistic merger of photoredox and cobaloxime catalyst. With respect to atom and step-economy ideals, this dual catalytic system enables the formation of high-value molecules from feedstock chemicals in a single step under room temperature.
Background: The plant working group of the Consortium for the Barcode of Life recommended the two-locus combination of rbcL + matK as the plant barcode, yet the combination was shown to successfully ...discriminate among 907 samples from 550 species at the species level with a probability of 72%. The group admits that the two-locus barcode is far from perfect due to the low identification rate, and the search is not over. Methodology/Principal Findings: Here, we compared seven candidate DNA barcodes (psbA-trnH, matK, rbcL, rpoC1, ycf5, ITS2, and ITS) from medicinal plant species. Our ranking criteria included PCR amplification efficiency, differential intra- and inter-specific divergences, and the DNA barcoding gap. Our data suggest that the second internal transcribed spacer (ITS2) of nuclear ribosomal DNA represents the most suitable region for DNA barcoding applications. Furthermore, we tested the discrimination ability of ITS2 in more than 6600 plant samples belonging to 4800 species from 753 distinct genera and found that the rate of successful identification with the ITS2 was 92.7% at the species level. Conclusions: The ITS2 region can be potentially used as a standard DNA barcode to identify medicinal plants and their closely related species. We also propose that ITS2 can serve as a novel universal barcode for the identification of a broader range of plant taxa.
is an important medicinal and edible plant with several pharmacologically active volatile oils. However, identifying
from
var.
and
which exhibit similar morphological characteristics to
, is ...difficult. The main goal of this study, therefore, is to mine genetic resources and improve molecular methods that could be used to distinguish these species. A total of eight complete chloroplasts (cp) genomes of these
species which were collected from the main producing areas in China were determined to be 163,608-164,069 bp in size. All genomes displayed a typical quadripartite structure with a pair of inverted repeat (IR) regions (29,820-29,959 bp) that separated a large single copy (LSC) region (88,680-88,857 bp) from a small single copy (SSC) region (15,288-15,369 bp). Each genome encodes 113 different genes with 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. More than 150 SSRs were identified in the entire cp genomes of these three species. The Sanger sequencing results based on 32
samples indicated that five highly divergent regions screened from cp genomes could not be used to distinguish
species. Phylogenetic analysis showed that the cp genomes could not only accurately identify
species, but also provide a solid foundation for the establishment of phylogenetic relationships of
species. The availability of cp genome resources and the comparative analysis is beneficial for species authentication and phylogenetic analysis in
.
The adulteration of herbal products is a threat to consumer safety. Here we surveyed the species composition of commercial Rhodiola products using DNA barcoding as a supervisory method. A Rhodiola ...dietary supplement DNA barcode database was successfully constructed using 82 voucher samples from 10 Rhodiola species. Based on the DNA barcoding standard operating procedure (SOP), we used this database to identify 100 Rhodiolae Crenulatae Radix et Rhizoma decoction piece samples that were purchased from drug stores and hospitals. The results showed that only 36 decoction piece sequences (40%) were authentic R. crenulata, which is recorded in Chinese Pharmacopeia, whereas the other samples were all adulterants and may indicate a potential safety issue. Among the adulterants, 35 sequences (38.9%) were authenticated as R. serrata, nine sequences (10%) were authenticated as R. rosea, which is documented in the United States Pharmacopeia, and the remaining samples were authenticated as other three Rhodiola species. This result indicates decoction pieces that are available in the market have complex origins and DNA barcoding is a convenient tool for market supervision.
We report a process route to fabricate an Al-Al interpenetrating-phase composite by combining the Al-Mg-Mn-Sc-Zr lattice structure and Al
84
Ni
7
Gd
6
Co
3
nanostructured structure. The lattice ...structure was produced by the selective laser melting and subsequently filled with the Al
84
Ni
7
Gd
6
Co
3
amorphous powder, and finally the mixture was used for hot extrusion to produce bulk samples. The results show that the composites achieve a high densification and good interface bonding due to the element diffusion and plastic deformation during hot extrusion. The bulk samples show a heterogeneous structure with a combination of honeycomb lattice structure with an average grain size of less than 1 µm and nanostructured area with a high volume fraction of nanometric intermetallics and nanograin α-Al. The heterogeneous structure leads to a bimodal mechanical zone with hard area and soft area giving rise to high strength and acceptable plasticity, where the compressive yield strength and the compressive plasticity can reach ∼745 MPa and ∼30%, respectively. The high strength can be explained by the rule of mixture, the grain boundary strengthening, and the back stress, while the acceptable plasticity is mainly owing to the confinement effect of the nanostructured area retarding the brittle fracture behavior.
Hepatitis A virus (HAV) genotype IA was most common among strains tested in US outbreak investigations and surveillance during 1996-2015. However, HAV genotype IB gained prominence during 2016-2019 ...person-to-person multistate outbreaks. Detection of previously uncommon strains highlights the changing molecular epidemiology of HAV infection in the United States.
Hepatitis C virus (HCV) infections are public health problem across the globe, particularly in developing countries. Pakistan has the second highest prevalence of HCV infection worldwide. Limited ...data exist from Pakistan about persons who inject drugs (PWID) and are at significant risk of exposure to HCV infection and transmission. Serum specimens (n = 110) collected from PWID residing in four provinces were tested for molecular markers of HCV infection. Next generation sequencing (NGS) of the hypervariable region (HVR1) of HCV and Global Hepatitis Outbreak and Surveillance Technology (GHOST) were used to determine HCV genotype, genetic heterogeneity, and construct transmission networks. Among tested specimens, 47.3% were found anti-HCV positive and 34.6% were HCV RNA-positive and belonged to four genotypes, with 3a most prevalent followed by 1a, 1b and 4a. Variants sampled from five cases formed phylogenetic cluster and a transmission network. One case harbored infection with two different genotypes. High prevalence of infections and presence of various genotypes indicate frequent introduction and transmission of HCV among PWID in Pakistan. Identification of a transmission cluster across three provinces, involving 20% of all cases, suggests the existence of a countrywide transmission network among PWIDs. Understanding the structure of this network should assist in devising effective public health strategies to eliminate HCV infection in Pakistan.
Objective
To investigate the clinicopathological features, diagnosis and differential diagnosis of patients with primary ovarian carcinoid tumours arising in mature cystic teratomas.
Methods
This ...retrospective case series analysed the data from patients with primary ovarian carcinoid tumours arising in mature cystic teratomas.
Results
The study enrolled four patients. Histopathological analysis of the tumours identified the following subtypes: insular (n = 1), trabecular (n = 1) and strumal (n = 2). All four primary ovarian carcinoid tumours originated from a mature teratoma. The morphology of the primary ovarian carcinoids was similar to other neuroendocrine tumours. Strumal carcinoids were composed of different proportions of thyroid tissue intimately admixed with carcinoid tumour. Tumour tissue was arranged in insular and/or trabecular patterns. The nucleus of tumour cells displayed exquisite chromatin without obvious mitotic figures. Tumour tissues were positively stained for neuroendocrine markers chromogranin A, synaptophysin and CD56 to varying degrees. Strumal carcinoid tumours were cytokeratin 19 positive and thyroid transcription factor 1 negative. No recurrence or metastasis occurred during follow-up (12–71 months).
Conclusion
Primary ovarian carcinoid tumours arising in mature cystic teratomas are rare. Diagnosis and differential diagnosis should be confirmed by clinical features, histopathological characteristics and specific immunophenotyping.
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![Oxidative [4+2] annulation ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2041-1723/small "Oxidative [4+2] annulation of styrenes with alkynes under external-oxidant-free conditions")
