Surface albedo measurements and surface type classification from helicopter-based observations during MOSAiC.

Global climate change poses significant societal and political challenges. The rapid increase in the near-surface air temperatures and the drastic retreat of the Arctic sea ice during summer are not well represented by climate models. The data sets introduced here intend to help improving the current understanding of the ongoing Arctic climate changes.

Profile observations of the Arctic atmospheric boundary layer with the BELUGA tethered balloon during MOSAiC.

During the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, the Balloon-bornE moduLar Utility for profilinG the lower Atmosphere (BELUGA) was deployed from an ice floe drifting in the Fram Strait from 29 June to 27 July 2020. The BELUGA observations aimed to characterize the cloudy Arctic atmospheric boundary layer above the sea ice using a modular setup of five instrument packages. The in situ measurements included atmospheric thermodynamic and dynamic state parameters (air temperature, humidity, pressure, and three-dimensional wind), broadband solar and terrestrial irradiance, aerosol particle microphysical properties, and cloud particle images.

MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC.

Two airborne field campaigns focusing on observations of Arctic mixed-phase clouds and boundary layer processes and their role with respect to Arctic amplification have been carried out in spring 2019 and late summer 2020 over the Fram Strait northwest of Svalbard. The latter campaign was closely connected to the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Comprehensive datasets of the cloudy Arctic atmosphere have been collected by operating remote sensing instruments, in-situ probes, instruments for the measurement of turbulent fluxes of energy and momentum, and dropsondes on board the AWI research aircraft Polar 5.

Effects of the shape distribution of aerosol particles on their volumetric scattering properties and the radiative transfer through the atmosphere that includes polarization.

In this paper, we investigate the effects of shape distribution of aerosol particles on the volumetric scattering properties, as well as the radiance and polarization distributions of skylight, by numerical simulations. The results demonstrate that the shape distribution indeed exerts a significant influence on the skylight degree of linear polarization. The skylight polarization calculated assuming the microscope-measured shape distributions is distinct from that using the inversion-based shape distributions.

ARCTIC CHANGE AND POSSIBLE INFLUENCE ON MID-LATITUDE CLIMATE AND WEATHER: A US CLIVAR White Paper.

Unlabelled: The Arctic has warmed more than twice as fast as the global average since the mid 20th century, a phenomenon known as Arctic amplification (AA). These profound changes to the Arctic system have coincided with a period of ostensibly more frequent events of extreme weather across the Northern Hemisphere (NH) mid-latitudes, including extreme heat and rainfall events and recent severe winters. Though winter temperatures have generally warmed since 1960 over mid-to-high latitudes, the acceleration in the rate of warming at high-latitudes, relative to the rest of the NH, started approximately in 1990.

Studying aerosol light scattering based on aspect ratio distribution observed by fluorescence microscope.

Particle shape is crucial to the properties of light scattered by atmospheric aerosol particles. A method of fluorescence microscopy direct observation was introduced to determine the aspect ratio distribution of aerosol particles. The result is comparable with that of the electron microscopic analysis.

Degradation of indoor limonene by outdoor ozone: A cascade of secondary organic aerosols.

In indoor air, terpene-ozone reactions can form secondary organic aerosols (SOA) in a transient process. 'Real world' measurements conducted in a furnished room without air conditioning were modelled involving the indoor background of airborne particulate matter, outdoor ozone infiltrated by natural ventilation, repeated transient limonene evaporations, and different subsequent ventilation regimes. For the given setup, we disentangled the development of nucleated, coagulated, and condensed SOA fractions in the indoor air and calculated the time dependence of the aerosol mass fraction (AMF) by means of a process model.

EURECA: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation.

Trade-wind cumuli constitute the cloud type with the highest frequency of occurrence on Earth, and it has been shown that their sensitivity to changing environmental conditions will critically influence the magnitude and pace of future global warming. Research over the last decade has pointed out the importance of the interplay between clouds, convection and circulation in controling this sensitivity. Numerical models represent this interplay in diverse ways, which translates into different responses of trade-cumuli to climate perturbations.

The lasting effect of limonene-induced particle formation on air quality in a genuine indoor environment.

Atmospheric ozone-terpene reactions, which form secondary organic aerosol (SOA) particles, can affect indoor air quality when outdoor air mixes with indoor air during ventilation. This study, conducted in Leipzig, Germany, focused on limonene-induced particle formation in a genuine indoor environment (24 m(3)). Particle number, limonene and ozone concentrations were monitored during the whole experimental period.

Sodium-iodide symporter positive cells after intracellular uptake of (99m)Tc versus α-emitter 211At. Reduction of clonogenic survival and characterization of DNA damage.

Purpose: We evaluated the DNA damaging potential of Auger electrons emitted in the decay of (99m)Tc compared to α-particles of 211At.

Material And Methods: The impact of (99m)Tc and 211At was monitored in a NIS-expressing rat thyroid cell model PCCl3 with varying, yet defined intra- and extracellular radionuclide distribution (using ± perchlorate). The radiotoxicity of (99m)Tc and 211At was studied by the comet assay under neutral and alkaline conditions and colony formation.

Reduction in clonogenic survival of sodium-iodide symporter (NIS)-positive cells following intracellular uptake of (99m)Tc versus (188)Re.

Purpose: Cellular radionuclide uptake increases the heterogeneity of absorbed dose to biological structures. Dose increase depends on uptake yield and emission characteristics of radioisotopes. We used an in vitro model to compare the impact of cellular uptake of (188)Re-perrhenate and (99m)Tc-pertechnetate on cellular survival.

Preincubation with Sn-complexes causes intensive intracellular retention of (99m)Tc in thyroid cells in vitro.

Unlabelled: Technetium radiopharmaceuticals are well established in nuclear medicine. Besides its well-known gamma radiation, (99m)Tc emits an average of five Auger and internal conversion electrons per decay. The biological toxicity of these low-energy, high-LET (linear energy transfer) emissions is a controversial subject.

Geant4-Simulations for cellular dosimetry in nuclear medicine.

The application of unsealed radionuclides in radiobiological experiments can lead to intracellular radionuclide uptake and an increased absorbed dose. Accurate dose quantification is essential to assess observed radiobiological effects. Due to small cellular dimensions direct dose measurement is impossible.

Particulate matter pollution in the megacities of the Pearl River Delta, China - a systematic literature review and health risk assessment.

The exposure to ambient particulate matter (PM) pollution is a major threat to public health. Chinese megacities are coined by high levels of PM. Our aims were to examine the concentration levels of PM in megacities (Guangzhou, Hong Kong, and Shenzhen) of the Pearl River Delta (PRD), South China; to compare the results with international and national air quality guidelines; and to assess the health impact in terms of possible reductions in premature deaths due to PM reduction.

[99mTc reduces clonogenic survival after intracellular uptake in NIS-positive cells in vitro more than 131I].

Aim: In addition to gamma radiation of 140 keV 99mTc emits during the transition to 99Tc electrons of low energy and tiny path-lengths. These Auger electrons cannot be utilized in diagnostic procedures. However, they were discussed frequently for therapeutic application.

[DNA damage in lymphocytes after irradiation with 211At and 188Re].

Aim: Ionising radiation produces many types of DNA lesions of different complexity. High linear energy transfer (LET) types of radiation are biological more effective than low LET radiation. In the present work we applied the single cell gel electrophoreses (comet assay) to study the induction of initial DNA damage, efficiency of repair and residual DNA damage in lymphocytes after treatment with 211At and 188Re.

[Cellular damage in vitro].

Aim: The cellular damage of ionising radiation depends on dose, physical radiation quality (e. g. LET) and intracellular radionuclide uptake.

Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: experiment.

We present effective radius, volume, surface-area, and number concentrations as well as mean complex refractive index of tropospheric particle size distributions based on lidar measurements at six wavelengths. The parameters are derived by means of an inversion algorithm that has been specifically designed for the inversion of available optical data sets. The data were taken on 20 June and on 20 July 1997 during the Aerosol Characterization Experiment ACE 2 (North Atlantic/Portugal) and on 9 August 1998 during the Lindenberg Aerosol Characterization Experiment LACE 98 (Lindenberg/Germany).

Bortezomib significantly impairs the immunostimulatory capacity of human myeloid blood dendritic cells.

Bortezomib is a potent drug for the treatment of multiple myeloma. Its anti-tumor activity is mediated by proteasome inhibition leading to decreased cell proliferation and induction of apoptosis. However, an unimpaired proteasomal function plays a crucial role for the induction of anti-tumor immunity by dendritic cells (DCs), which are currently used for therapeutic vaccination against various tumors including myeloma.