Tumors of the gastrointestinal system represent a significant share of solid tumors worldwide. Despite the advances in diagnosis and treatment, the prognosis of gastrointestinal tumors is still very ...poor and improved therapies are indispensable. Cytokine-induced killer (CIK) cells are feasible for an immunotherapeutic approach as they are easily available and have an advantageous biologic profile; they are rapidly proliferating and their high cytotoxicity is non-MHC-restricted. We summarize and discuss twenty recent clinical studies applying CIK cells for the treatment of gastric, pancreatic, hepatocellular, and colorectal cancer. Autologous CIK cells were transfused intravenously, intraperitoneally, or via the common hepatic artery. In all studies side effects and toxicity of CIK cell therapy were mild and easily controllable. The combination of CIK cell therapy with conventional adjuvant or palliative therapies was superior to the standard therapy alone, indicating the benefit of CIK cell therapy for cancer patients. Thus, CIK cells represent a promising immunotherapy for the treatment of gastrointestinal tumors. The optimal treatment schedule and ideal combination with conventional therapies should be evaluated in further clinical studies.
Ice nucleating particles (INPs) affect the radiative properties of cold clouds. Knowledge concerning their concentration above ground level and their potential sources is scarce. Here we present the ...first highly temperature resolved ice nucleation spectra of airborne samples from an aircraft campaign during late winter in 2018. Most INP spectra featured low concentration levels (<3 · 10−4 L−1 at −15°C). However, we also found INP concentrations of up to 1.8·10−2 L−1 at −15°C and freezing onsets as high as −7.5°C for samples mainly from the marine boundary layer. Shape and onset temperature of the ice nucleation spectra of those samples as well as heat sensitivity hint at biogenic INP. Colocated measurements additionally indicate a local marine influence rather than long‐range transport. Our results suggest that even in late winter above 80°N a local marine source for biogenic INP, which can efficiently nucleate ice at high temperatures, is present.
Plain Language Summary
Clouds are a key factor in the energy budget of the Arctic atmosphere. Ice nucleating particles (INPs) can modify the radiation properties and lifetime of clouds by affecting the relative abundance of liquid and frozen droplets in a cloud. Despite this important ability, knowledge about the INP concentration above ground level is limited as airborne INP measurements are very scarce in the Arctic. Here we present results from an aircraft campaign, which took place during the late winter of 2018 in latitudes above 80°N. We found INP concentrations at above −15°C, which are similar to those found in midlatitudes. These INPs also initiate freezing already at high temperatures. We found indications that the INPs are biogenic and originate from a local, marine source, rather than being transported from midlatitudes into the Arctic. Due to the presence of numerous cracks, open leads and polynyas in the sea ice in the investigation area, the ocean may provide a source for these biogenic INP in an environment, where sources on land are still shrouded in snow and ice. However, in a warming Arctic contributions from different sources might change, making the characterization of the current state important.
Key Points
Ice nucleating particles on airborne filter samples containing mainly Arctic marine boundary layer aerosol initiate freezing at −7.5°C
At −15°C, concentrations of ice nucleating particles ranged from up to 2 · 10−2 L−1 down to below 10−3 L−1
A local marine source and biogenic origin for the high‐temperature ice nucleating particles is likely
Airborne measurements of solar spectral radiance reflected by cirrus are performed with the HALO-Solar Radiation (HALO-SR) instrument onboard the High Altitude and Long Range Research Aircraft (HALO) ...in November 2010. The data are used to quantify the influence of surface albedo variability on the retrieval of cirrus optical thickness and crystal effective radius. The applied retrieval of cirrus optical properties is based on a standard two-wavelength approach utilizing measured and simulated reflected radiance in the visible and near-infrared spectral region. Frequency distributions of the surface albedos from Moderate resolution Imaging Spectroradiometer (MODIS) satellite observations are used to compile surface-albedo-dependent lookup tables of reflected radiance. For each assumed surface albedo the cirrus optical thickness and effective crystal radius are retrieved as a function of the assumed surface albedo. The results for the cirrus optical thickness are compared to measurements from the High Spectral Resolution Lidar (HSRL). The uncertainty in cirrus optical thickness due to local variability of surface albedo in the specific case study investigated here is below 0.1 and thus less than that caused by the measurement uncertainty of both instruments. It is concluded that for the retrieval of cirrus optical thickness the surface albedo variability is negligible. However, for the retrieval of crystal effective radius, the surface albedo variability is of major importance, introducing uncertainties up to 50%. Furthermore, the influence of the bidirectional reflectance distribution function (BRDF) on the retrieval of crystal effective radius was investigated and quantified with uncertainties below 10%, which ranges below the uncertainty caused by the surface albedo variability. The comparison with the independent lidar data allowed for investigation of the role of the crystal shape in the retrieval. It is found that if assuming aggregate ice crystals, the HSRL observations fit best with the retrieved optical thickness from HALO-SR.
Based on airborne spectral imaging observations, three-dimensional (3-D) radiative effects between Arctic boundary layer clouds and highly variable Arctic surfaces were identified and quantified. A ...method is presented to discriminate between sea ice and open water under cloudy conditions based on airborne nadir reflectivity gamma lambda measurements in the visible spectral range. In cloudy cases the transition of gamma lambda from open water to sea ice is not instantaneous but horizontally smoothed. In general, clouds reduce gamma lambda above bright surfaces in the vicinity of open water, while gamma lambda above open sea is enhanced. With the help of observations and 3-D radiative transfer simulations, this effect was quantified to range between 0 and 2200 m distance to the sea ice edge (for a dark-ocean albedo of alpha water = 0.042 and a sea-ice albedo of alpha ice = 0.91 at 645 nm wavelength). The affected distance Delta L was found to depend on both cloud and sea ice properties. For a low-level cloud at 0-200 m altitude, as observed during the Arctic field campaign VERtical Distribution of Ice in Arctic clouds (VERDI) in 2012, an increase in the cloud optical thickness tau from 1 to 10 leads to a decrease in Delta L from 600 to 250 m. An increase in the cloud base altitude or cloud geometrical thickness results in an increase in Delta L; for tau = 1/10 Delta L = 2200 m/1250 m in case of a cloud at 500-1000 m altitude. To quantify the effect for different shapes and sizes of ice floes, radiative transfer simulations were performed with various albedo fields (infinitely long straight ice edge, circular ice floes, squares, realistic ice floe field). The simulations show that Delta L increases with increasing radius of the ice floe and reaches maximum values for ice floes with radii larger than 6 km (500-1000 m cloud altitude), which matches the results found for an infinitely long, straight ice edge. Furthermore, the influence of these 3-D radiative effects on the retrieved cloud optical properties was investigated. The enhanced brightness of a dark pixel next to an ice edge results in uncertainties of up to 90 and 30 % in retrievals of tau and effective radius reff, respectively. With the help of Delta L, an estimate of the distance to the ice edge is given, where the retrieval uncertainties due to 3-D radiative effects are negligible.
The sensitivity of passive remote sensing measurements to retrieve microphysical parameters of convective clouds, in particular their thermodynamic phase, is investigated by three-dimensional (3-D) ...radiative transfer simulations. The effects of different viewing geometries and vertical distributions of the cloud microphysical properties are investigated. Measurement examples of spectral solar radiance reflected by cloud sides (passive) in the near-infrared (NIR) spectral range are performed together with collocated lidar observations (active). The retrieval method to distinguish the cloud thermodynamic phase (liquid water or ice) exploits different slopes of cloud side reflectivity spectra of water and ice clouds in the NIR. The concurrent depolarization backscattering lidar provides geometry information about the cloud distance and height as well as the depolarization.
Spectral airborne upward and downward irradiance measurements are used to derive the area-averaged surface albedo. Real surfaces are not homogeneous in their reflectivity. Therefore, this work ...studies the effects of the heterogeneity of surface reflectivity on the area-averaged surface albedo to quantify how well aircraft measurements can resolve the small-scale variability of the local surface albedo. For that purpose spatially heterogeneous surface albedo maps were input into a 3-dimensional (3-D) Monte Carlo radiative transfer model to simulate 3-D irradiance fields. The calculated up- and downward irradiances in altitudes between 0.1 and 5 km are used to derive the area-averaged surface albedo using an iterative retrieval method that removes the effects due to atmospheric scattering and absorption within the layer beneath the considered level. For the case of adjacent land and sea surfaces, parametrizations are presented which quantify the horizontal distance from the coastline that is required to reduce surface heterogeneity effects on the area-averaged surface albedo to a given limit. The parametrization which is a function of altitude, aerosol optical depth, single scattering albedo, and the ratio of local land and sea albedo was applied for airborne spectral measurements. In addition, the deviation between area-averaged and local surface albedo is determined for more complex surface albedo maps. For moderate aerosol conditions (optical depth less than 0.4) and a wavelength range between 400 and 1000 nm, the altitude and the heterogeneity of the surface albedo are the dominant factors determining the mean deviation between local and area-averaged surface albedo. A parametrization of the mean deviation is applied to an albedo map that was derived from a Landsat image of an area in East Anglia (UK). Parametrization and direct comparison of local and area-averaged surface albedo show similar mean deviations (20% vs. 25%) over land.
First data from collocated, helicopter‐based measurements of boundary layer cloud microphysical properties (effective droplet radius Reff, droplet number concentration N) and spectral radiative ...quantities (cloud optical thickness τ, cloud top albedo ρ, reflectivity ) are presented. The in situ measurements of the microphysical cloud properties were collected by the Airborne Cloud Turbulence Observation System (ACTOS) attached to a helicopter by a 145 m long rope. Cloud spectral reflectivity was derived from radiances measured by grating spectrometers combined with downward looking optical inlets installed underneath the helicopter. Correlations between cloud microphysics and reflected radiation are presented for two cloud cases with different optical and geometrical thicknesses. On the basis of common retrieval techniques, τ and Reff are derived using a radiative transfer model. The results of the retrieval are compared to the collocated in situ measurements and data from the Moderate‐Resolution Imaging Spectroradiometer (MODIS). Within the limitations of the relatively small data set, the feasibility of closely collocated microphysics and radiation data and their benefits were demonstrated.
MODIS (MOderate-resolution Imaging Spectroradiometer) retrievals of aerosol optical depth (AOD) are biased over urban areas, primarily because the reflectance characteristics of urban surfaces are ...different than that assumed by the retrieval algorithm. Specifically, the operational "dark-target" retrieval is tuned towards vegetated (dark) surfaces and assumes a spectral relationship to estimate the surface reflectance in blue and red wavelengths. From airborne measurements of surface reflectance over the city of Zhongshan, China, were collected that could replace the assumptions within the MODIS retrieval algorithm. The subsequent impact was tested upon two versions of the operational algorithm, Collections 5 and 6 (C5 and C6). AOD retrieval results of the operational and modified algorithms were compared for a specific case study over Zhongshan to show minor differences between them all. However, the Zhongshan-based spectral surface relationship was applied to a much larger urban sample, specifically to the MODIS data taken over Beijing between 2010 and 2014. These results were compared directly to ground-based AERONET (AErosol RObotic NETwork) measurements of AOD. A significant reduction of the differences between the AOD retrieved by the modified algorithms and AERONET was found, whereby the mean difference decreased from 0.27±0.14 for the operational C5 and 0.19±0.12 for the operational C6 to 0.10±0.15 and -0.02±0.17 by using the modified C5 and C6 retrievals. Since the modified algorithms assume a higher contribution by the surface to the total measured reflectance from MODIS, consequently the overestimation of AOD by the operational methods is reduced. Furthermore, the sensitivity of the MODIS AOD retrieval with respect to different surface types was investigated. Radiative transfer simulations were performed to model reflectances at top of atmosphere for predefined aerosol properties. The reflectance data were used as input for the retrieval methods. It was shown that the operational MODIS AOD retrieval over land reproduces the AOD reference input of 0.85 for dark surface types (retrieved AOD = 0.87 (C5)). An overestimation of AOD = 0.99 is found for urban surfaces, whereas the modified C5 algorithm shows a good performance with a retrieved value of AOD = 0.86.
Low-level airborne observations of the Arctic surface radiative energy budget are discussed. We focus on the terrestrial part of the budget, quantified by the thermal-infrared net irradiance (TNI). ...The data were collected in cloudy and cloud-free conditions over and in the vicinity of the marginal sea ice zone (MIZ) close to Svalbard during two aircraft campaigns conducted in the spring of 2019 and in the early summer of 2017. The measurements, complemented by ground-based observations available from the literature and radiative transfer simulations, are used to evaluate the influence of surface type (sea ice, open ocean, MIZ), seasonal characteristics, and synoptically driven meridional air mass transports into and out of the Arctic on the near-surface TNI. The analysis reveals a typical four-mode structure of the frequency distribution of the TNI as a function of surface albedo, the sea ice fraction, and surface brightness temperature. Two modes prevail over sea ice and another two over open ocean, each representing cloud-free and cloudy radiative states. Characteristic shifts and modifications of the TNI modes during the transition from winter to spring and early summer conditions are discussed. Furthermore, the influence of warm air intrusions (WAIs) and marine cold-air outbreaks (MCAOs) on the near-surface downward thermal-infrared irradiances and the TNI is highlighted for several case studies. It is concluded that during WAIs the surface warming depends on cloud properties and evolution. Lifted clouds embedded in warmer air masses over a colder sea ice surface, decoupled from the ground by a surface-based temperature inversion, have the potential to warm the surface more strongly than near-surface fog or thin low-level boundary layer clouds because of a higher cloud base temperature. For MCAOs it is found that the thermodynamic profile of the southward-moving air mass adapts only slowly to the warmer ocean surface.
Metastatic renal cell carcinoma (RCC) seems to be resistant to conventional chemo- and radiotherapy and the general treatment regimen of cytokine therapy produces only modest responses while inducing ...severe side effects. Nowadays standard of care is the treatment with VEGF-inhibiting agents or mTOR inhibition; nevertheless, immunotherapy can induce complete remissions and long-term survival in selected patients. Among different adoptive lymphocyte therapies, cytokine-induced killer (CIK) cells have a particularly advantageous profile as these cells are easily available, have a high proliferative rate, and exhibit a high antitumor activity. Here, we reviewed clinical studies applying CIK cells, either alone or with standard therapies, for the treatment of RCC. The adverse events in all studies were mild, transient, and easily controllable. In vitro studies revealed an increased antitumor activity of peripheral lymphocytes of participants after CIK cell treatment and CIK cell therapy was able to induce complete clinical responses in RCC patients. The combination of CIK cell therapy and standard therapy was superior to standard therapy alone. These studies suggest that CIK cell immunotherapy is a safe and competent treatment strategy for RCC patients and further studies should investigate different treatment combinations and schedules for optimal application of CIK cells.
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