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Krumland J, Velja S, Cocchi C. Quantum Dots in Transition Metal Dichalcogenides Induced by Atomic-Scale Deformations. ACS Photonics 2024; 11:586-595. [PMID: 38405397 PMCID: PMC10885200 DOI: 10.1021/acsphotonics.3c01470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 02/27/2024]
Abstract
Single-photon emission from monolayer transition metal dichalcogenides requires the existence of localized, atom-like states within the extended material. Here, we predict from first-principles the existence of quantum dots around atomic-scale protrusions, which result from substrate roughness or particles trapped between layers. Using density functional theory, we find such deformations to give rise to local membrane stretching and curvature, which lead to the emergence of gap states. Having enhanced outer-surface localization, they are prone to mixing with states pertaining to chalcogen vacancies and adsorbates. If the deformation is sharp, the conduction band minimum furthermore assumes atomic and valley-mixed character, potentially enabling quantum light emission. When such structural defects are arranged in an array, the new states couple to form energetically separated sub-bands, holding promise for intriguing superlattice dynamics. All of the observed features are shown to be closely linked to elastic, deformation-induced intra- and intervalley scattering processes.
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Affiliation(s)
- Jannis Krumland
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
- Physics
Department and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
| | - Stefan Velja
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
| | - Caterina Cocchi
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
- Physics
Department and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
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Flathmann C, Meyer T, Titova V, Schmidt J, Seibt M. Composition and electronic structure of [Formula: see text]/[Formula: see text]/Al passivating carrier selective contacts on n-type silicon solar cells. Sci Rep 2023; 13:3124. [PMID: 36813814 PMCID: PMC9946942 DOI: 10.1038/s41598-023-29831-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/10/2023] [Indexed: 02/24/2023] Open
Abstract
Carrier-selective and passivating SiO[Formula: see text]/TiO[Formula: see text] heterocontacts are an attractive alternative to conventional contacts due to their high efficiency potentials combined with relatively simple processing schemes. It is widely accepted that post deposition annealing is necessary to obtain high photovoltaic efficiencies, especially for full area aluminum metallized contacts. Despite some previous high-level electron microscopy studies, the picture of atomic-scale processes underlying this improvement seems to be incomplete. In this work, we apply nanoscale electron microscopy techniques to macroscopically well-characterized solar cells with SiO[Formula: see text]/TiO[Formula: see text]/Al rear contacts on n-type silicon. Macroscopically, annealed solar cells show a tremendous decrease of series resistance and improved interface passivation. Analyzing the microscopic composition and electronic structure of the contacts, we find that partial intermixing of the SiO[Formula: see text] and TiO[Formula: see text] layers occurs due to annealing, leading to an apparent thickness reduction of the passivating SiO[Formula: see text]. However, the electronic structure of the layers remains clearly distinct. Hence, we conclude that the key to obtain highly efficient SiO[Formula: see text]/TiO[Formula: see text]/Al contacts is to tailor the processing such that the excellent chemical interface passivation of a SiO[Formula: see text] layer is achieved for a layer thin enough to allow efficient tunneling through the layer. Furthermore, we discuss the impact of aluminum metallization on the above mentioned processes.
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Affiliation(s)
- Christoph Flathmann
- 4th Institute of Physics– Solids and Nanostructures, University of Goettingen, 37077 Göttingen, Germany
| | - Tobias Meyer
- 4th Institute of Physics– Solids and Nanostructures, University of Goettingen, 37077 Göttingen, Germany
- Institute of Materials Physics, University of Goettingen, 37077 Göttingen, Germany
| | - Valeriya Titova
- Institute for Solar Energy Research Hamelin (ISFH), 31860 Emmerthal, Germany
- Institute of Solid-State Physics, Leibniz University Hannover, 30167 Hannover, Germany
| | - Jan Schmidt
- Institute for Solar Energy Research Hamelin (ISFH), 31860 Emmerthal, Germany
- Institute of Solid-State Physics, Leibniz University Hannover, 30167 Hannover, Germany
| | - Michael Seibt
- 4th Institute of Physics– Solids and Nanostructures, University of Goettingen, 37077 Göttingen, Germany
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Stankov MV, Cossmann A, Bonifacius A, Dopfer-Jablonka A, Ramos GM, Gödecke N, Scharff AZ, Happle C, Boeck AL, Tran AT, Pink I, Hoeper MM, Blasczyk R, Winkler MS, Nehlmeier I, Kempf A, Hofmann-Winkler H, Hoffmann M, Eiz-Vesper B, Pöhlmann S, Behrens GMN. Humoral and Cellular Immune Responses Against Severe Acute Respiratory Syndrome Coronavirus 2 Variants and Human Coronaviruses After Single BNT162b2 Vaccination. Clin Infect Dis 2021; 73:2000-2008. [PMID: 34134134 PMCID: PMC8384414 DOI: 10.1093/cid/ciab555] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Vaccine-induced neutralizing antibodies are key in combating the coronavirus disease 2019 (COVID-19) pandemic. However, delays of boost immunization due to limited availability of vaccines may leave individuals vulnerable to infection and prolonged or severe disease courses. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC)-B.1.1.7 (United Kingdom), B.1.351 (South Africa), and P.1 (Brazil)-may exacerbate this issue, as the latter two are able to evade control by antibodies. METHODS We assessed humoral and T-cell responses against SARS-CoV-2 wild-type (WT), VOC, and endemic human coronaviruses (hCoVs) that were induced after single and double vaccination with BNT162b2. RESULTS Despite readily detectable immunoglobulin G (IgG) against the receptor-binding domain of the SARS-CoV-2 S protein at day 14 after a single vaccination, inhibition of SARS-CoV-2 S-driven host cell entry was weak and particularly low for the B.1.351 variant. Frequencies of SARS-CoV-2 WT and VOC-specific T cells were low in many vaccinees after application of a single dose and influenced by immunity against endemic hCoV. The second vaccination significantly boosted T-cell frequencies reactive for WT and B.1.1.7 and B.1.351 variants. CONCLUSIONS These results call into question whether neutralizing antibodies significantly contribute to protection against COVID-19 upon single vaccination and suggest that cellular immunity is central for the early defenses against COVID-19.
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Affiliation(s)
- Metodi V Stankov
- Department of Rheumatology and Immunology, Hannover
Medical School, Hannover, Germany
| | - Anne Cossmann
- Department of Rheumatology and Immunology, Hannover
Medical School, Hannover, Germany
| | - Agnes Bonifacius
- Institute of Transfusion Medicine and Transplant
Engineering, Hannover Medical School,
Hannover, Germany
| | - Alexandra Dopfer-Jablonka
- Department of Rheumatology and Immunology, Hannover
Medical School, Hannover, Germany
- German Center for Infection Research, partner site
Hannover-Braunschweig, Braunschweig,
Germany
| | - Gema Morillas Ramos
- Department of Rheumatology and Immunology, Hannover
Medical School, Hannover, Germany
| | - Nina Gödecke
- Institute of Transfusion Medicine and Transplant
Engineering, Hannover Medical School,
Hannover, Germany
| | - Anna Zychlinsky Scharff
- Department of Pediatric Pneumology, Allergology and
Neonatology, Hannover Medical School,
Hannover, Germany
| | - Christine Happle
- Department of Pediatric Pneumology, Allergology and
Neonatology, Hannover Medical School,
Hannover, Germany
- German Center for Lung Research, Biomedical Research in
End Stage and Obstructive Lung Disease,
Hannover, Germany
| | - Anna-Lena Boeck
- Department for Neurology, Hannover Medical
School, Hannover, Germany
| | - Anh Thu Tran
- Department for Neurology, Hannover Medical
School, Hannover, Germany
| | - Isabell Pink
- Department of Pneumology, Hannover Medical School, member
of the German Center for Lung Research,
Hannover, Germany
| | - Marius M Hoeper
- Department of Pneumology, Hannover Medical School, member
of the German Center for Lung Research,
Hannover, Germany
| | - Rainer Blasczyk
- Institute of Transfusion Medicine and Transplant
Engineering, Hannover Medical School,
Hannover, Germany
| | - Martin S Winkler
- Department of Anaesthesiology and Intensive Care Unit,
University of Göttingen Medical Center, Georg-August University of
Göttingen, Göttingen, Germany
| | - Inga Nehlmeier
- Infection Biology Unit, German Primate
Center, Göttingen, Germany
| | - Amy Kempf
- Infection Biology Unit, German Primate
Center, Göttingen, Germany
| | | | - Markus Hoffmann
- Infection Biology Unit, German Primate
Center, Göttingen, Germany
- Faculty of Biology and Psychology,
Georg-August-Universität Göttingen,
Göttingen, Germany
| | - Britta Eiz-Vesper
- Institute of Transfusion Medicine and Transplant
Engineering, Hannover Medical School,
Hannover, Germany
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate
Center, Göttingen, Germany
- Faculty of Biology and Psychology,
Georg-August-Universität Göttingen,
Göttingen, Germany
| | - Georg M N Behrens
- Department of Rheumatology and Immunology, Hannover
Medical School, Hannover, Germany
- German Center for Infection Research, partner site
Hannover-Braunschweig, Braunschweig,
Germany
- Centre for Individualized Infection
Medicine, Hannover, Germany
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Dupont A, Sommer F, Zhang K, Repnik U, Basic M, Bleich A, Kühnel M, Bäckhed F, Litvak Y, Fulde M, Rosenshine I, Hornef MW. Age-Dependent Susceptibility to Enteropathogenic Escherichia coli (EPEC) Infection in Mice. PLoS Pathog 2016; 12:e1005616. [PMID: 27159323 PMCID: PMC4861285 DOI: 10.1371/journal.ppat.1005616] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/15/2016] [Indexed: 01/14/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) represents a major causative agent of infant diarrhea associated with significant morbidity and mortality in developing countries. Although studied extensively in vitro, the investigation of the host-pathogen interaction in vivo has been hampered by the lack of a suitable small animal model. Using RT-PCR and global transcriptome analysis, high throughput 16S rDNA sequencing as well as immunofluorescence and electron microscopy, we characterize the EPEC-host interaction following oral challenge of newborn mice. Spontaneous colonization of the small intestine and colon of neonate mice that lasted until weaning was observed. Intimate attachment to the epithelial plasma membrane and microcolony formation were visualized only in the presence of a functional bundle forming pili (BFP) and type III secretion system (T3SS). Similarly, a T3SS-dependent EPEC-induced innate immune response, mediated via MyD88, TLR5 and TLR9 led to the induction of a distinct set of genes in infected intestinal epithelial cells. Infection-induced alterations of the microbiota composition remained restricted to the postnatal period. Although EPEC colonized the adult intestine in the absence of a competing microbiota, no microcolonies were observed at the small intestinal epithelium. Here, we introduce the first suitable mouse infection model and describe an age-dependent, virulence factor-dependent attachment of EPEC to enterocytes in vivo.
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Affiliation(s)
- Aline Dupont
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (AD); (MWH)
| | - Felix Sommer
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Kaiyi Zhang
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Marijana Basic
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - André Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Mark Kühnel
- Institute for Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Fredrik Bäckhed
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Yael Litvak
- Department for Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Marcus Fulde
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Ilan Rosenshine
- Department for Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mathias W. Hornef
- Institute for Medical Microbiology, RWTH Aachen University Hospital, Aachen, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- * E-mail: (AD); (MWH)
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