Laser facilitated epicutaneous peptide immunization using dry patch technology

The skin has been intensely investigated as a target tissue for immunization because it is populated by multiple types of antigen presenting cells. Directly addressing dendritic cells or Langerhans cells in vivo represents an attractive strategy for inducing T cell responses in cancer immunotherapy. We and others have studied fractional laser ablation as a novel method combining efficient delivery of macromolecules to the skin with an inherent adjuvant effect of laser illumination. In this proof of concept study, we demonstrate the feasibility of peptide delivery to the skin using the P.L.E.A.S.E. professional Erb:YAG fractional infrared laser together with EPIMMUN patches. In an ovalbumin mouse model we demonstrate that a dry patch formulation of SIINFEKL peptide in combination with CpG-ODN1826, but not imiquimod or polyI:C, induces potent cytotoxic T cell responses, which can be further boosted by co-delivery of the pan-helper T cell epitope PADRE.

The Initiation of Dry Patches in Cloud-Resolving Convective Self-Aggregation Simulations: Boundary Layer Dry-Subsidence Feedback

Self-aggregation of convection can be considered as the simultaneous occurrence of dry patch initiation/amplification and wet patch contraction/intensification from initially uniform moisture and temperature fields. As the twin of wet patches, dry patches play an important role in moisture and energy balance during convective self-aggregation. In this study, the WRF Model is used to study the initiation of dry patches in convective self-aggregation, especially the continuous drying in their boundary layer (BL). In the dry patch BL, increased air density leads to an enhanced high pressure anomaly, which drives an amplifying BL divergent flow and induces an amplifying BL subsidence. The virtual effect of drying by subsidence counteracts warming by subsidence and the BL process, further increasing BL air density. Our analysis indicates the existence of a dry-subsidence feedback, which leads to the initiation of dry patches in convective self-aggregation. This feedback is shown to be important even in very large-scale (3000 km × 9000 km) cloud-resolving convective self-aggregation simulations.

Impact of an Interactive SST on the Convective Aggregation Process

<p>The spontaneous aggregation of convective clouds over a moist portion of the domain is ubiquitous in cloud resolving model simulations. This phenomenon significantly reduces the domain mean total water vapor and enhances the outgoing long radiation. In this study we use the system of atmospheric modeling (SAM) in a radiative-convective equilibrium (RCE) setup in order to investigate the impact of an interactive sea surface temperature (SST) on the aggregation progress. We use a slab ocean (with depth of 5, 10 and 50 m) with constant target SST to which the domain mean SST is relaxed. Our results show that, consistent with previous studies, an interactive SST delays the aggregation with a larger impact for a shallower slab. This effect is enhanced for a smaller target SST.</p><p>The aggregation proceeds by the expansion of non-convective dry areas. Before aggregation, dry areas are associated with warmer surface due to enhanced short-wave radiation. During and after the aggregation, a single large dry patch develops and is associated with a colder surface. This cooling is due to a reduction in downwelling long-wave radiation and to enhanced latent heat flux due to drier boundary layer. The edge of the dry patch has warm SST anomaly forming a ring of warm water around it that favors divergence of low-level moist air from the dry patch and accelerates dry patch expansion. This is favored by a positive surface pressure anomaly (PSFC) in the dry patch.</p><p>Therefore, at first, the warm SST anomaly opposes the divergent flow from dry regions, opposing the aggregation. Then the cold SST anomaly that develops in dry regions increases the divergent flow and favors the dry patch expansion. For a small ocean slab, the warm SST anomaly that develops in the dry areas at early times inhibits the dry patch expansion and can significantly delay the beginning of aggregation.</p>

A Computational Study of Thin Film Dynamics on Micro-Structured Surfaces

The present study is motivated by interest in understanding of physical mechanisms that govern the effect of material and micro-structural characteristics of heat surface on boiling heat transfer and burnout at high heat fluxes. The effect was reported and investigated experimentally and analytically over several past decades. Only recently, with the advent of nanotechnology including microscale manufacturing, it becomes possible to perform high heat-flux boiling experiments with control of surface conditions. Of particular importance for practice is the potential for significant enhancement of boiling heat transfer (BHT) and critical heat flux (CHF) in pool and flow boiling on heaters with specially manufactured and controlled micro-structured surfaces. This enhancement is very important to a very wide range of engineering applications, like heat exchanger and cooling system, where maximum flux is needed. Currently, there are many controlled experiments that investigate such effect and they lend themselves a subject for detailed computational analysis. The focus of this study is micro-hydrodynamics of the evaporating thin liquid film at the receding triple contact line, corresponding to formation of dry spot in the footprint of a growing bubble. Parametric investigations are performed to assess the hypotheses that micro-structured surfaces enhance resilience to burnout due to residual liquid in the dry patch after contact line receding. Towards the study objective, a particle-based (mesh-less) method of computational fluid dynamics called Smoothed Particle Hydrodynamics (SPH) is adopted. The SPH method is selected for its capability to handle fluid dynamics in complex geometries and free surface problems without mass loss (characteristic of alternative interface capturing schemes used in mesh-based methods). Both surface tension and surface adhesion (hydrophilicity) are implemented and tested. The solid (heater) surface and manufactured micro-structures are represented by solid-type particles. Heat transfer, phase change (evaporation) and vapor dynamics are not included in the present simulation. The bouncing drop case measures the contact time of water droplet with solid surface. This case is used for “mesh” sensitivity (particle size) study and calibration of boundary conditions and surface tension coefficient. Subsequently, case studies are formulated and performed for contact line dynamics on heater surfaces with the fabricated Micro Pillar Arrays surfaces (MPA) and smooth surface. Variable characteristics include surface tension and pillar density on structured surface (modified by changing distance between pillars). First of all, residual fluid are found in all simulations with structured surface, while fluid are drained for smooth cases. For structured surface, it’s found that after the contact line recedes, fluid with higher surface tension resides in the dry patch more than fluid with lower coefficient, and the relation tends to be non-linear. While for smooth surface, all fluid will be drained after certain time and the relations are non-monotonic; it’s also found that the amount of residual fluid increase as the distance between pillars decreases until a limit. The fluid then starts to decrease with pillars being set further apart. The increase starts from 30 μm and the limit is around 10 μm.