In this topical review, we report on recent advances on the coupling of single semiconductor quantum emitters, quantum dots, to the dynamic strain and electric fields of surface acoustic waves. ...Quantum dots are atom-like optically addressable two-level systems embedded in semiconductor matrices. On the one hand, the occupancy states of these 'artificial atoms' can be programmed by spatio-temporal carrier dynamics driven by sound waves. On the other hand, the quantized energy levels of electrons and holes couple strongly to the mechanical strain of these waves. We present an overview of the fundamental coupling mechanisms, experimental techniques to probe these systems in the time domain, and recent hallmark experiments. We discuss emerging research themes including hybrid architectures comprising advanced LiNbO3 SAW devices and single quantum dot devices of nanowire-based quantum emitters, and sound-driven control of light-matter interaction between single photons in nanophotonic resonators and two-level quantum dot systems.
The 2019 surface acoustic waves roadmap Delsing, Per; Cleland, Andrew N; Schuetz, Martin J A ...
Journal of physics. D, Applied physics,
08/2019, Letnik:
52, Številka:
35
Journal Article
Recenzirano
Odprti dostop
Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these ...nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.
Prime editing is a recent genome editing technology using fusion proteins of Cas9-nickase and reverse transcriptase, that holds promise to correct the vast majority of genetic defects. Here, we ...develop prime editing for primary adult stem cells grown in organoid culture models. First, we generate precise in-frame deletions in the gene encoding β-catenin (CTNNB1) that result in proliferation independent of Wnt-stimuli, mimicking a mechanism of the development of liver cancer. Moreover, prime editing functionally recovers disease-causing mutations in intestinal organoids from patients with DGAT1-deficiency and liver organoids from a patient with Wilson disease (ATP7B). Prime editing is as efficient in 3D grown organoids as in 2D grown cell lines and offers greater precision than Cas9-mediated homology directed repair (HDR). Base editing remains more reliable than prime editing but is restricted to a subgroup of pathogenic mutations. Whole-genome sequencing of four prime-edited clonal organoid lines reveals absence of genome-wide off-target effects underscoring therapeutic potential of this versatile and precise gene editing strategy.
Abstract
Microbially mediated nitrogen cycling in carbon-dominated cold seep environments remains poorly understood. So far anaerobic methanotrophic archaea (ANME-2) and their sulfate-reducing ...bacterial partners (SEEP-SRB1 clade) have been identified as diazotrophs in deep sea cold seep sediments. However, it is unclear whether other microbial groups can perform nitrogen fixation in such ecosystems. To fill this gap, we analyzed 61 metagenomes, 1428 metagenome-assembled genomes, and six metatranscriptomes derived from 11 globally distributed cold seeps. These sediments contain phylogenetically diverse nitrogenase genes corresponding to an expanded diversity of diazotrophic lineages. Diverse catabolic pathways were predicted to provide ATP for nitrogen fixation, suggesting diazotrophy in cold seeps is not necessarily associated with sulfate-dependent anaerobic oxidation of methane. Nitrogen fixation genes among various diazotrophic groups in cold seeps were inferred to be genetically mobile and subject to purifying selection. Our findings extend the capacity for diazotrophy to five candidate phyla (Altarchaeia, Omnitrophota, FCPU426, Caldatribacteriota and UBA6262), and suggest that cold seep diazotrophs might contribute substantially to the global nitrogen balance.
The lack of microbial genomes and isolates from the deep seabed means that very little is known about the ecology of this vast habitat. Here, we investigate energy and carbon acquisition strategies ...of microbial communities from three deep seabed petroleum seeps (3 km water depth) in the Eastern Gulf of Mexico. Shotgun metagenomic analysis reveals that each sediment harbors diverse communities of chemoheterotrophs and chemolithotrophs. We recovered 82 metagenome-assembled genomes affiliated with 21 different archaeal and bacterial phyla. Multiple genomes encode enzymes for anaerobic oxidation of aliphatic and aromatic compounds, including those of candidate phyla Aerophobetes, Aminicenantes, TA06 and Bathyarchaeota. Microbial interactions are predicted to be driven by acetate and molecular hydrogen. These findings are supported by sediment geochemistry, metabolomics, and thermodynamic modelling. Overall, we infer that deep-sea sediments experiencing thermogenic hydrocarbon inputs harbor phylogenetically and functionally diverse communities potentially sustained through anaerobic hydrocarbon, acetate and hydrogen metabolism.
The application of endoscopic therapies for early cancers of the esophagus is limited by the possible presence of regional lymph node metastases. Our objective was to determine the prevalence and ...predictors of lymph node metastases in patients with pT1 carcinoma of the esophagus and the gastric cardia.
The National Cancer Institute's Surveillance Epidemiology and End Results Database (2004 to 2010) was used to identify all patients with pT1 carcinomas who underwent primary surgical resection for squamous cell carcinoma (SCC) or adenocarcinoma (EAC) of the esophagus and of the esophagogastric junction (AEG). Prevalence of lymph node metastases was assessed, and survival in all types of cancer was calculated. Multivariate logistic regression was used to identify factors predicting positive lymph node status.
There were 1,225 patients (84% male), with a mean age of 64 ± 10 years, and 90% were white. Intramucosal disease was present in 44% of patients, and submucosal invasion (T1b) was present in 692 (56%). Prevalence of lymph node metastases in EAC, SCC, and AEG was 6.4%, 6.9%, and 9.5% for pT1a tumors and 19.6%, 20%, and 22.9% for pT1b tumors, respectively. In patients with more than 23 lymph nodes removed during resection, prevalence of lymph node metastases in EAC, SCC, and AEG was 8.1%, 25%, and 7.4% for pT1a tumors and 27.8%, 33.3%, and 22% for pT1b tumors, respectively. Positive lymph node status was associated with worse overall 5-year survival in EAC (N0 vs N+: 78% vs 52%) and AEG (N0 vs N+: 83% vs 44%) but did not have a significant effect on the long-term survival of patients with SCC. Infiltration of the submucosa, tumor size exceeding 10 mm, and poor tumor differentiation were independently associated with the risk of nodal disease. Prevalence of lymph node metastasis negative for these three risk factors was only 4.8%.
Prevalence of lymph node metastasis in early esophageal cancer is high in patients with T1 cancer. Inadequate lymphadenectomy underestimates lymph node status. Endoscopic treatment can be considered only in a select group of patients with early esophageal cancer.
Background & Aims The comparative efficacy and safety of infliximab and azathioprine therapy alone or in combination for ulcerative colitis (UC) have not been evaluated previously. Methods This ...randomized, double-blind trial evaluated the efficacy and safety of 16 weeks of treatment with infliximab monotherapy, azathioprine monotherapy, or the 2 drugs combined in tumor necrosis factor-α antagonist-naive adults with moderate to severe UC. Patients were assigned randomly to receive intravenous infusions of infliximab 5 mg/kg at weeks 0, 2, 6, and 14 plus daily oral placebo capsules; oral azathioprine 2.5 mg/kg daily plus placebo infusions on the infliximab schedule; or combination therapy with the 2 drugs. Corticosteroid-free clinical remission (primary end point, week 16) was evaluated at weeks 8 and 16. The study was terminated before the enrollment target was reached. Results A total of 239 patients were included in efficacy analyses. Baseline characteristics were similar between treatment groups. Corticosteroid-free remission at week 16 was achieved by 39.7% (31 of 78) of patients receiving infliximab/azathioprine, compared with 22.1% (17 of 77) receiving infliximab alone ( P = .017) and 23.7% (18 of 76) receiving azathioprine alone ( P = .032). Mucosal healing at week 16 occurred in 62.8% (49 of 78) of patients receiving infliximab/azathioprine, compared with 54.6% (42 of 77) receiving infliximab ( P = .295) and 36.8% (28 of 76) receiving azathioprine ( P = .001). Serious infections occurred in 2 patients (1 patient receiving infliximab, and 1 patient receiving azathioprine). Conclusions Anti–tumor necrosis factor-α–naive patients with moderate to severe UC treated with infliximab plus azathioprine were more likely to achieve corticosteroid-free remission at 16 weeks than those receiving either monotherapy. Combination therapy led to significantly better mucosal healing than azathioprine monotherapy. ClinicalTrials.gov number, NCT00537316.
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