10 research outputs found
Detection of nanoplastic by surface-enhanced Raman microscopy
Currently the extent of nanoplastic in the environment can only be estimated
by extrapolation from the plastic waste that can be detected. To be able to
quantify the whole extent of the problem, detection methods have to be
developed that can also identify particles that are smaller than 1 m. Here
we employ surface-enhanced Raman scattering (SERS) to image and identify single
nanoplastic particles down to 100 nm in size. We obtain an experimental
enhancement factor of more than three orders of magnitude measured on a single
plastic particle instead of averaging over a concentration. Our results
contribute to the better understanding and employment of SERS for nanoparticle
detection and present an important step for the development of future sensors.Comment: 9 pages, 7 figure
Nanofiber-based high-Q microresonator for cryogenic applications
We demonstrate a cryo-compatible, fully fiber-integrated, alignment-free
optical microresonator. The compatibility with low temperatures expands its
possible applications to the wide field of solid-state quantum optics, where a
cryogenic environment is often a requirement. At a temperature of 4.6 K we
obtain a quality factor of . In conjunction
with the small mode volume provided by the nanofiber, this cavity can be either
used in the coherent dynamics or the fast cavity regime, where it can provide a
Purcell factor of up to 15. Our resonator is therefore suitable for
significantly enhancing the coupling between light and a large variety of
different quantum emitters and due to its proven performance over a wide
temperature range, also lends itself for the implementation of quantum hybrid
systems.Comment: 9 pages, 3 figure
Efficacy and safety of oral methazolamide in patients with type 2 diabetes: A 24-week, placebo-controlled, double-blind study
OBJECTIVE To evaluate the safety and efficacy of methazolamide as a potential therapy for type 2 diabetes. RESEARCH DESIGN AND METHODS This double-blind, placebo-controlled study randomized 76 patients to oral methazolamide (40 mg b.i.d.) or placebo for 24 weeks. The primary efficacy end point for methazolamide treatment was a placebo-corrected reduction in HbA1c from baseline after 24 weeks (ÎHbA1c). RESULTS Mean ± SD baseline HbA1c was 7.1 ± 0.7% (54 ± 5 mmol/mol; n = 37) and 7.4 ± 0.6% (57 ± 5 mmol/mol; n = 39) in the methazolamide and placebo groups, respectively. Methazolamide treatment was associated with a ÎHbA1c of â0.39% (95% CI â0.82, 0.04; P < 0.05) (â4.3 mmol/mol [â9.0, 0.4]), an increase in the proportion of patients achieving HbA1c â€6.5% (48 mmol/mol) from 8 to 33%, a rapid reduction in alanine aminotransferase (âŒ10 units/L), and weight loss (2%) in metformin-cotreated patients. CONCLUSIONS Methazolamide is the archetype for a new intervention in type 2 diabetes with clinical benefits beyond glucose control
Imaging and identification of single nanoplastic particles and agglomerates
Abstract Pollution by nanoplastic is a growing environmental and health concern. Currently the extent of nanoplastic in the environment can only be cumbersomely and indirectly estimated but not measured. To be able to quantify the extent of the problem, detection methods that can identify nanoplastic particles that are smaller than 1 Ό m are critically needed. Here, we employ surface-enhanced Raman scattering (SERS) to image and identify single nanoplastic particles down to 100 nm in size. We can differentiate between single particles and agglomerates and our method allows an improvement in detection speed of 10 7 compared to state-of-the art surface-enhanced Raman imaging. Being able to resolve single particles allows to measure the SERS enhancement factor on individual nanoplastic particles instead of averaging over a concentration without spatial information. Our results thus contribute to the better understanding and employment of SERS for nanoplastic detection and present an important step for the development of future sensors
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Nanofiber-based high-Q microresonator for cryogenic applications
We demonstrate a cryo-compatible, fully fiber-integrated, alignment-free optical microresonator. The compatibility with low temperatures expands its possible applications to the wide field of solid-state quantum optics, where a cryogenic environment is often a requirement. At a temperature of 4.6 K we obtain a quality factor of (9.9 ± 0.7) à 106. In conjunction with the small mode volume provided by the nanofiber, this cavity can be either used in the coherent dynamics or the fast cavity regime, where it can provide a Purcell factor of up to 15. Our resonator is therefore suitable for significantly enhancing the coupling between light and a large variety of different quantum emitters and due to its proven performance over a wide temperature range, also lends itself for the implementation of quantum hybrid systems. © 2020 OSA - The Optical Society. All rights reserved
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Thermal tuning of a fiber-integrated Fabry-PĂ©rot cavity
Here, we present the thermal tuning capability of an alignment-free, fiber-integrated Fabry-PĂ©rot cavity. The two mirrors are made of fiber Bragg gratings that can be individually temperature stabilized and tuned. We show the temperature tuning of the resonance wavelength of the cavity without any degradation of the finesse and the tuning of the individual stop bands of the fiber Bragg gratings. This not only permits for the cavityâs finesse to be optimized post-fabrication but also makes this cavity applicable as a narrowband filter with a FWHM spectral width of 0.07â±â0.02 pm and a suppression of more than -15 dB that can be wavelength tuned. Further, in the field of quantum optics, where strong light-matter interactions are desirable, quantum emitters can be coupled to such a cavity and the cavity effect can be reversibly omitted and re-established. This is particularly useful when working with solid-state quantum emitters where such a reference measurement is often not possible once an emitter has been permanently deposited inside a cavity
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Quantum Emitter Localization in Layer-Engineered Hexagonal Boron Nitride.
Hexagonal boron nitride (hBN) is a promising host material for room-temperature, tunable solid-state quantum emitters. A key technological challenge is deterministic and scalable spatial emitter localization, both laterally and vertically, while maintaining the full advantages of the 2D nature of the material. Here, we demonstrate emitter localization in hBN in all three dimensions via a monolayer (ML) engineering approach. We establish pretreatment processes for hBN MLs to either fully suppress or activate emission, thereby enabling such differently treated MLs to be used as select building blocks to achieve vertical (z) emitter localization at the atomic layer level. We show that emitter bleaching of ML hBN can be suppressed by sandwiching between two protecting hBN MLs, and that such thin stacks retain opportunities for external control of emission. We exploit this to achieve lateral (x-y) emitter localization via the addition of a patterned graphene mask that quenches fluorescence. Such complete emitter site localization is highly versatile, compatible with planar, scalable processing, allowing tailored approaches to addressable emitter array designs for advanced characterization, monolithic device integration, and photonic circuits.European Unionâs Horizon 2020, Austrian Academy of Sciences, Royal Societ