Chemical composition, size distributions, and degree of
oligomerization of secondary organic aerosol (SOA) from α-pinene
(C10H16) ozonolysis were investigated for low-temperature
conditions (223 K). ...Two types of experiments were performed using two
simulation chambers at the Karlsruhe Institute of Technology: the Aerosol
Preparation and Characterization (APC) chamber, and the Aerosol Interaction
and Dynamics in the Atmosphere (AIDA) chamber. Experiment type 1 simulated
SOA formation at upper tropospheric conditions: SOA was generated in the AIDA
chamber directly at 223 K at 61 % relative humidity (RH; experiment
termed “cold humid”, CH) and for comparison at 6 % RH (experiment
termed “cold dry”, CD) conditions. Experiment type 2 simulated SOA
uplifting: SOA was formed in the APC chamber at room temperature (296 K) and
< 1 % RH (experiment termed “warm dry”, WD) or 21 % RH
(experiment termed “warm humid”, WH) conditions, and then partially
transferred to the AIDA chamber kept at 223 K, and 61 % RH (WDtoCH) or
30 % RH (WHtoCH), respectively. Precursor concentrations varied between
0.7 and 2.2 ppm α-pinene, and between 2.3 and 1.8 ppm ozone for type 1 and
type 2 experiments, respectively. Among other instrumentation, a chemical
ionization mass spectrometer (CIMS) coupled to a filter inlet for gases and
aerosols (FIGAERO), deploying I− as reagent ion, was used for SOA
chemical composition analysis. For type 1 experiments with lower α-pinene concentrations and cold SOA
formation temperature (223 K), smaller particles of 100–300 nm vacuum
aerodynamic diameter (dva) and higher mass fractions
(> 40 %) of adducts (molecules with more than 10 carbon
atoms) of α-pinene oxidation products were observed. For type 2
experiments with higher α-pinene concentrations and warm SOA formation
temperature (296 K), larger particles (∼ 500 nm dva) with
smaller mass fractions of adducts (< 35 %) were produced. We also observed differences (up to 20 ∘C) in maximum desorption
temperature (Tmax) of individual compounds desorbing from the
particles deposited on the FIGAERO Teflon filter for different experiments,
indicating that Tmax is not purely a function of a compound's
vapor pressure or volatility, but is also influenced by diffusion limitations
within the particles (particle viscosity), interactions between particles
deposited on the filter (particle matrix), and/or particle mass on the
filter. Highest Tmax were observed for SOA under dry conditions
and with higher adduct mass fraction; lowest Tmax were observed for SOA under
humid conditions and with lower adduct mass fraction. The observations
indicate that particle viscosity may be influenced by intra- and
inter-molecular hydrogen bonding between oligomers, and particle water
uptake, even under such low-temperature conditions. Our results suggest that particle physicochemical properties such as
viscosity and oligomer content mutually influence each other, and that
variation in Tmax of particle desorptions may have
implications for particle viscosity and particle matrix effects. The
differences in particle physicochemical properties observed between our
different experiments demonstrate the importance of taking experimental
conditions into consideration when interpreting data from laboratory studies
or using them as input in climate models.
Living templates: Gold, silver, platinum, and palladium nanoparticles are synthesized. The as‐obtained citrate‐stabilized solutions are used as growth media for a variety of fungi. The nanoparticles ...partly assemble onto the mycelia, leading to a hybrid structure which consists of a biological template covered with nanoparticles. Supercritical drying of these structures conserves the three‐dimensional tubular shape.
► We developed a new method for determination of the degree of N-acetylation of chitin and chitosan. ► We used first derivative diamond ATR FTIR spectroscopy. ► The new method allows the ...determination of the degree of N-acetylation in the presence of water. ► The new method was compared to results obtained by UV spectroscopy, elemental analysis, and Raman spectroscopy.
A new method for the determination of the degree of N-acetylation (DA) of chitin and chitosan is described using first derivative diamond ATR FTIR spectroscopy. Applying the derivative values of the amide III band at 1327cm−1 and the CH deformation band of the N-acetyl group at 1383cm−1 as measure of the N-acetyl content of the sample in relation to the derivative value of the bridge oxygen vibration at 1163cm−1 as internal standard, a linear correlation to the results of first derivative UV spectroscopy was obtained and confirmed by elemental analysis and Raman spectroscopy. The described method allows the determination of the degree of N-acetylation of chitosan and chitin in the presence of water thus making drying procedures unnecessary.
Abstract
The outcome of T cell activation is determined by mechanisms that balance Ca
2+
influx and clearance. Here we report that murine CD4 T cells lacking Neuroplastin (
Nptn
−/−
), an ...immunoglobulin superfamily protein, display elevated cytosolic Ca
2+
and impaired post-stimulation Ca
2+
clearance, along with increased nuclear levels of NFAT transcription factor and enhanced T cell receptor-induced cytokine production. On the molecular level, we identified plasma membrane Ca
2+
ATPases (PMCAs) as the main interaction partners of Neuroplastin. PMCA levels were reduced by over 70% in
Nptn
−/−
T cells, suggesting an explanation for altered Ca
2+
handling. Supporting this, Ca
2+
extrusion was impaired while Ca
2+
levels in internal stores were increased. T cells heterozygous for PMCA1 mimicked the phenotype of
Nptn
−/−
T cells. Consistent with sustained Ca
2+
levels, differentiation of
Nptn
−/−
T helper cells was biased towards the Th1 versus Th2 subset. Our study thus establishes Neuroplastin-PMCA modules as important regulators of T cell activation.
Learning and memory processes are accompanied by rearrangements of synaptic protein networks. While various studies have demonstrated the regulation of individual synaptic proteins during these ...processes, much less is known about the complex regulation of synaptic proteomes. Recently, we reported that auditory discrimination learning in mice is associated with a relative down‐regulation of proteins involved in the structural organization of synapses in various brain regions. Aiming at the identification of biological processes and signaling pathways involved in auditory memory formation, here, a label‐free quantification approach was utilized to identify regulated synaptic junctional proteins and phosphoproteins in the auditory cortex, frontal cortex, hippocampus, and striatum of mice 24 h after the learning experiment. Twenty proteins, including postsynaptic scaffolds, actin‐remodeling proteins, and RNA‐binding proteins, were regulated in at least three brain regions pointing to common, cross‐regional mechanisms. Most of the detected synaptic proteome changes were, however, restricted to individual brain regions. For example, several members of the Septin family of cytoskeletal proteins were up‐regulated only in the hippocampus, while Septin‐9 was down‐regulated in the hippocampus, the frontal cortex, and the striatum. Meta analyses utilizing several databases were employed to identify underlying cellular functions and biological pathways. Data are available via ProteomeExchange with identifier PXD003089.
How does the protein composition of synapses change in different brain areas upon auditory learning? We unravel discrete proteome changes in mouse auditory cortex, frontal cortex, hippocampus, and striatum functionally implicated in the learning process. We identify not only common but also area‐specific biological pathways and cellular processes modulated 24 h after training, indicating individual contributions of the regions to memory processing.
How does the protein composition of synapses change in different brain areas upon auditory learning? We unravel discrete proteome changes in mouse auditory cortex, frontal cortex, hippocampus, and striatum functionally implicated in the learning process. We identify not only common but also area‐specific biological pathways and cellular processes modulated 24 h after training, indicating individual contributions of the regions to memory processing.
We developed a fluid dynamic model to predict the size and material dependent particle deposition efficiencies for a commercial available exposure chamber. Validated by measurements with SiO2 and ...polystyrene particle standards between 29nm and 2μm we obtained a parameterization of the particle deposition efficiency for a specific set of practically relevant flow, pressure and temperature conditions that can be used for accurate dose calculations at these conditions. Furthermore, the model predicts that a significant impact on the deposition efficiency due to the fractal-like structure of nanoparticle agglomerates is expected for cluster sizes beyond 200nm mobility equivalent diameter. For the commercially available gravitation–diffusion based exposure chamber investigated here at one specific flow rate, the results indicate that deposition rates of particles smaller than 100nm are too low in order to deposit mass doses that are equivalent to typical cytotoxic LOAELs determined in submerged experiments within reasonable times.
•We model and measure deposition efficiencies in a commercial exposure chamber.•We estimate the difference between spherical and fractal-like structured particles.•The deposition efficiency is given as a function of size and density.•Above 200nm the deposition efficiency decreases compared to spheres•The presented model allows easy and accurate dose estimations.
Purpose
This study aims to examine the health-related quality of life in patients with hepatocellular carcinoma.
Methods
181 patients attending a tertiary center outpatient clinic were interviewed ...and completed the short form 36 (SF36) questionnaire. The SF36 was used to assess health-related QoL. Cross-sectional analyses by group (age, gender, clinical scores, systemic, and local interventions) as well sequel questionnaires were conducted.
Results
Participants included were 79% (143/181) men mean age at first SF36: 63.8 (± 12.3; 18.4–85.8) years. Barcelona Clinic Liver Cancer (BCLC) stadium C was associated with significantly lower SF36 total scores, and elevated initial alpha-fetoprotein (AFP) concentrations were associated with lower SF36 functional and mental health sum scores throughout the course of the third questionnaire. Patients treated with sorafenib had within the sub-dimension scores a significantly lower result for role limitations due to physical health compared to patients without sorafenib treatment. Patients who underwent a transarterial chemoembolization (TACE) had within the sub-dimension scores a significantly higher result for control of pain compared to patients without TACE. Kaplan–Meier analysis revealed significant survival benefits for patients who underwent any intervention at the first SF36 (mean survival in years 4.3 vs. 1.6;
P
< 0.01) as well as for patients who underwent hepatic resection (mean survival in years 6.3 vs. 2.7;
P
< 0.0001).
Conclusion
Advanced tumor stages marked by BCLC stadium C and elevated initial AFP concentrations were associated with lower SF36 total scores and functional sum scores, respectively. During the course of sorafenib treatment, the sub-dimensional score for role limitations due to physical health decreased significantly, whereas TACE performance was associated with a significant improvement of the control of body pain.
Standard first-line treatment of aggressive B cell lymphoma comprises six or eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus eight doses of rituximab (R). ...Whether adding two doses of rituximab to six cycles of R-CHOP is of therapeutic benefit has not been systematically investigated. The Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial investigated the ability of
18
F-fluorodesoxyglucose PET scanning to guide treatment in aggressive non-Hodgkin lymphomas. Patients with B cell lymphomas and a negative interim scan received six cycles of R-CHOP with or without two extra doses of rituximab. For reasons related to trial design, only about a third underwent randomization between the two options. Combining randomized and non-randomized patients enabled subgroup analyses for diffuse large B cell lymphoma (DLBCL;
n
= 544), primary mediastinal B cell lymphoma (PMBCL;
n
= 37), and follicular lymphoma (FL) grade 3 (
n
= 35). With a median follow-up of 52 months, increasing the number of rituximab administrations failed to improve outcome. A non-significant trend for improved event-free survival was seen in DLBCL high-risk patients, as defined by the International Prognostic Index, while inferior survival was observed in female patients below the age of 60 years. Long-term outcome in PMBCL was excellent. Differences between FL grade 3a and FL grade 3b were not apparent. The results were confirmed in a Cox proportional hazard regression model and a propensity score matching analysis. In conclusion, adding two doses of rituximab to six cycles of R-CHOP did not improve outcome in patients with aggressive B cell lymphomas and a fast metabolic treatment response.
This paper provides a survey of recent studies on the optical properties of aerosol and cloud particles that have been conducted at the AIDA facility of Forschungszentrum Karlsruhe (Aerosol ...Interactions and Dynamics in the Atmosphere). Reflecting the broad accessible temperature range of the AIDA chamber which extends from ambient temperature down to 183
K, the investigations feature a broad diversity of research topics, such as the wavelength-dependence of the specific absorption cross sections of soot and mineral dust aerosols at room temperature, depolarization and infrared extinction measurements of ice crystal clouds generated at temperatures below 235
K, and the optical properties of polar stratospheric cloud constituents whose formation was studied in chamber experiments at temperatures well below 200
K. After reviewing the AIDA research activity of the past decade and introducing the optical instrumentation of the AIDA facility, this paper presents illustrative examples of ongoing and already published work on optical measurements of soot aerosols, mineral dust particles, and ice crystal clouds.
The sectional aerosol behavior code COSIMA simulates the time evolution of the structural, dynamical, and optical properties of airborne agglomerate particles as well as their heterogeneous chemical ...interactions with reactive trace gases utilizing a formalism based on fractal scaling laws. The modeled processes include diffusion to the walls and sedimentational deposition, Brownian and gravitational coagulation, molecular transport from the gas phase to the accessible particle surface, surface adsorption and reactions, gas phase reactions, and dilution effects due to sampling (e.g. during aerosol chamber experiments). The effect of hydrodynamic interactions and shielding on particle mobility is considered within the framework of the Kirkwood–Riseman theory. Rayleigh–Debye–Gans theory is used to deal with light absorption and scattering. The code is validated against new experimental data on the dynamics of Diesel and graphite spark soot as well as recent theoretical and simulation results. Applying the Kirkwood–Riseman formalism to compute the mobility of fractal like agglomerates significantly enhances coagulation rates as well as wall and depositional loss but does not affect the form of the self preserving size distributions attained in the long time regime if Brownian coagulation dominates the aerosol dynamics.
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