15 research outputs found
CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers
For three austral summer seasons (2013â2016, each from December to February)
aerosol particles arriving at the Belgian Antarctic research station Princess
Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized.
This included number concentrations of total aerosol
particles (NCN) and cloud condensation nuclei (NCCN),
the particle number size distribution (PNSD), the aerosol particle
hygroscopicity, and the influence of the air mass origin on NCN
and NCCN. In general NCN was found to range from
40Â to 6700 cmâ3, with a median of 333 cmâ3, while
NCCNÂ was found to cover a range between less than 10Â and
1300 cmâ3 for supersaturations (SSs) between 0.1 % and 0.7 %. It is
shown that the aerosol is dominated by the Aitken mode, being characterized by a
significant amount of small, and therefore likely secondarily formed, aerosol
particles, with 94 % and 36 % of the aerosol particles smaller than
90Â and â35 nm, respectively. Measurements of the basic
meteorological parameters as well as the history of the air masses arriving
at the measurement station indicate that the station is influenced by both
marine air masses originating from the Southern Ocean and coastal areas
around Antarctica (marine events â MEs) and continental air masses
(continental events â CEs). CEs, which were defined as instances when the air
masses spent at least 90 % of the time over the
Antarctic continent during the last 10Â days prior to arrival at the measurements station, occurred during 61 % of the time during which
measurements were done. CEs came along with rather constant NCN
and NCCNÂ values, which we denote as Antarctic continental
background concentrations. MEs, however, cause large fluctuations
in NCN and NCCN, with low concentrations likely caused
by scavenging due to precipitation and high concentrations likely originating
from new particle formation (NPF) based on marine precursors. The application
of HYSPLIT back trajectories in form of the potential source contribution
function (PSCF) analysis indicate that the region of the Southern Ocean is a
potential source of Aitken mode particles. On the basis of PNSDs, together
with NCCNÂ measured at an SS of 0.1 %, median values for the
critical diameter for cloud droplet activation and the aerosol particle
hygroscopicity parameter Îș were determined to be 110 nm and 1,
respectively. For particles larger than â110 nm the Southern Ocean
together with parts of the Antarctic ice shelf regions were found to be
potential source regions. While the former may contribute sea spray particles
directly, the contribution of the latter may be due to the emission of sea salt
aerosol particles, released from snow particles from surface snow layers,
e.g., during periods of high wind speed, leading to drifting or blowing snow.
The region of the Antarctic inland plateau, however, was not found to feature a
significant source region for aerosol particles in general or for cloud condensation nuclei measured at the PEÂ station in
the austral summer.</p
Role of TNFα in pulmonary pathophysiology
Tumor necrosis factor alpha (TNFα) is the most widely studied pleiotropic cytokine of the TNF superfamily. In pathophysiological conditions, generation of TNFα at high levels leads to the development of inflammatory responses that are hallmarks of many diseases. Of the various pulmonary diseases, TNFα is implicated in asthma, chronic bronchitis (CB), chronic obstructive pulmonary disease (COPD), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In addition to its underlying role in the inflammatory events, there is increasing evidence for involvement of TNFα in the cytotoxicity. Thus, pharmacological agents that can either suppress the production of TNFα or block its biological actions may have potential therapeutic value against a wide variety of diseases. Despite some immunological side effects, anti-TNFα therapeutic strategies represent an important breakthrough in the treatment of inflammatory diseases and may have a role in pulmonary diseases characterized by inflammation and cell death
Nanoparticle drug loading as a design parameter to improve docetaxel pharmacokinetics and efficacy
Nanoparticle (NP) drug loading is one of the key defining characteristics of a NP formulation. However, the effect of NP drug loading on therapeutic efficacy and pharmacokinetics has not been thoroughly evaluated. Herein, we characterized the efficacy, toxicity and pharmacokinetic properties of NP docetaxel formulations that have differential drug loading but are otherwise identical. Particle Replication in Non-wetting Templates (PRINT(Âź)), a soft-lithography fabrication technique, was used to formulate NPs with identical size, shape and surface chemistry, but with variable docetaxel loading. The lower weight loading (9%-NP) of docetaxel was found to have a superior pharmacokinetic profile and enhanced efficacy in a murine cancer model when compared to that of a higher docetaxel loading (20%-NP). The 9%-NP docetaxel increased plasma and tumor docetaxel exposure and reduced liver, spleen and lung exposure when compared to that of 20%-NP docetaxel