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Helicon waves are excited in a plasma wave facility by a half-turn double-helix antenna operating at 13.56 MHz for static magnetic fields ranging from 200 to 1000 G. A non-perturbing optical probe located outside the Pyrex™ plasma chamber is used to observe 443 nm Ar II emission that is spatially and temporally correlated with the helicon wave. The Ar II emission is measured along with wave magnetic and Langmuir probe density measurements at various axial and radial positions. 105 GHz interferometry is used to verify the bulk temperature corrected Langmuir probe measurements. The measured peak Ar II emission phase velocity is compared to the measured wave magnetic field phase velocity and code predicted wave phase velocity for the transition and blue mode regimes. Very different properties of the optical emission peak phase and wave characteristics for the transition and helicon modes of operation are observed. Comparison of the experimental results with the ANTENAII code [Y. Mouzouris and J. E. Scharer, ...

Summary form only given. Low-pressure microwave-excited microplasmas1 are promising sources of VUV photons for a variety of applications, including photoionization for mass spectrometry. A split-ring resonator microstrip architecture can be used to initiate and sustain these microplasmas using the extremely high electric field generated in the sub-millimeter gap between electrodes. The VUV flux, primarily the result of resonance radiation following electronic excitation of rare gas atoms, is a sensitive function of the distribution of electron energies. Direct measurement of the electron energy distribution (EED) could provide critical insight into the physics of the microplasma operation. We present Thomson scattering measurements of the EED in a split-ring resonator argon microplasma operating at 2.5 GHz and approximately 1 Torr. The diagnostic consists of a Q-switched Nd:YAG laser operating at 532 nm. Thomsonscattered light is collected with a high throughput (f/2) triple grating imaging spectrometer and an intensified CCD camera gated to the laser pulses. Stray and Rayleigh-scattered laser light, which can exceed the intensity of the Thomsonscattered light by factors of over 105, is filtered out using a mask placed between the first two gratings, which are operated in subtractive mode. Other available diagnostics include VUV flux measured using a vacuum UV monochromator. Plasma parameters are measured as a function of gas flow rate, absorbed microwave power, and spatial location both within the plasma cavity and in the downstream plume. Experimental results of the EED and VUV flux are compared with computational modeling using the Hybrid Plasma Equipment Model (HPEM).2 In this model, the EED and radiation transport are computed using Monte Carlo simulations, and neutral gas and plasma transport are addressed using fluid techniques. These experimental and computational modeling results provide a means for optimizing the VUV flux produced by the source.

S | Carcinogenesis & Cancer Genetics 074 Bullous leukemia cutis in a patient with T-cell prolymphocytic leukemia Q Jiang, S Siu, S Onder Alpdogan, A Gochoco, J Gong, J Lee and J Sahu 1 Dermatology, Thomas Jefferson University, Philadelphia, PA, 2 Pathology, Thomas Jefferson University, Philadelphia, PA and 3 Medical Oncology, Thomas Jefferson University, Philadelphia, PA T-cell prolymphocytic leukemia (T-PLL) is a rare neoplasm of mature T lymphocytes. Cutaneous involvement, e.g., leukemia cutis (LC), is a characteristic symptom of T-PLL and appears in up to one-third of cases. LC may follow, precede or occur concomitantly with the diagnosis of systemic leukemia, however, vesiculo-bullous LCs are rare. So far, few were reported in chronic lymphocytic leukemia, but none in T-PLL. T-PLL is a relatively unknown disease in the field of dermatology, and moreover, variable leukemic cutaneous manifestations, especially the non-specific lesions of bullous LC, make it clinically difficult to distinguish from other non-specific lesions. We report here a case of leukaemia cutis with vesiculo-bullous lesions in a patient who was recently diagnosed with T-PLL and has been on chemotherapy. A skin biopsy specimen showed dense infiltration of small lymphocytes in the dermis, and subsequent immunogenotyping confirmed the presence of leukemia cells in the same patterns of previous biopsies of the lymph node. To our knowledge, this is the first report of vesiculo-bullous LC in a patient with T-PLL. LC is an indicator of poor prognosis and often requires more aggressive therapies. Proper diagnosis of LC is essential because it can alter the appropriate treatment for a patient. S14 Journal of Investigative Dermatology (2016), Volume 136 075 Ephrin-A loss in cutaneous squamous cell carcinoma progression and metastasis J Zheng, B Perez White, N Kaplan, A Petty, Z Zhao, K Honda, M Denning, M Blumenberg, S Getsios and B Wang 1 Dermatology, Northwestern U., Chicago, IL, 2 Case Western Reserve U., Cleveland, OH, 3 Loyola U., Chicago, IL and 4 New York U., New York, NY Glycophosphatidylinositol-linked ephrin-A proteins target EphA receptor tyrosine kinases (RTKs) to promote keratinocyte differentiation and maintain tissue homeostasis. Accordingly, genetic ablation of EphA2, a major epidermal EphA subtype, increases susceptibility to chemically induced skin carcinogenesis in mice. Defining the corresponding role of ligands for EphA2 in skin cancer has been more cumbersome as the three ephrin-A genes (efna1, efna3, efna4) proximal to the epidermal differentiation complex gene cluster are each prominently expressed in skin. We met this challenge by engineering a triple efnA1/3/4 knock-out mouse (efnA-TKO mice) that reflects the pattern of reduced efnA gene expression found in mouse and human cutaneous SCCs. Skin tumors were evident earlier and grew faster in mice lacking these three ephrin-A ligands or EphA2. While histologically benign papillomas were prominent in EphA2-deficient mice, efnA-TKO mice developed invasive squamous cell carcinomas that metastasized to the lymph nodes and lungs within 25 weeks of DMBA-TPA treatment. Using primary mouse and human cell culture models, we found that ephrin-A proteins operate within the epidermis by targeting EphA2 to limit keratinocyte migration. We also illustrated a key tumor suppressive role for ephrin-A ligands in the surrounding tumor microenvironment by re-introducing isogenic tumor cell lines into the skin of wild-type or efnA-TKO mice. Importantly, the invasive phenotype of efnA-TKO mouse tumor cell lines was normalized by genetic reintroduction of efnA3. Integrating our findings from human tumors, mouse models, and primary cell cultures provides strong support for the notion that ephrins operate within tumor cells and also in the microenvironment to suppress skin cancer growth and metastasis. 076 Senescent fibroblasts enhance squamous cell carcinoma progression through secretion of Chemerin and activation of MAPK pathway V Farsam, A Basu, M Gatzka, M Wlaschek, N Treiber, MA Mulaw, T Lucas, S Kochanek and K Scharffetter-Kochanek 1 Department of Dermatology and Allergic Diseases, University of Ulm, Ulm, Germany, 2 Institute of Experimental Cancer Research, University of Ulm, Ulm, Germany and 3 Department of Gene Therapy, University of Ulm, Ulm, Germany Aging is associated with an increased risk of cutaneous squamous cell carcinoma (cSCC) partly due to the accumulation of mutations in stem/progenitor cells and partly due to the acquisition of a senescence-associated secretory phenotype (SASP) by senescent fibroblasts in dermal stroma. However, the mechanisms underlying the SASP-induced cSCC progression are not sufficiently understood. We investigated the SASP effect of senescent human dermal fibroblasts on cSCC cell motility in vitro using Transwell migration assay. Conditioned media (CM) of senescent fibroblasts significantly increased the migration of cSCC lines in comparison to young CM. Using RT-qPCR and specific ELISA, high levels of Chemerin transcripts and protein were found in senescent compared to young fibroblasts. An increase in Chemerin immunostaining in dermal fibroblasts of skin sections from old healthy individuals were observed as opposed to almost absent Chemerin immunostaining in young skin. Enhanced expression of Chemerin receptor CCRL2 was detected in cSCC lines when compared to normal keratinocytes. Increased CCRL2 was also confirmed with immunostaining of skin biopsies derived from patients suffering from cSCC. Recombinant human (rh) Chemerin enhanced the migration of cSCC lines in a concentration-dependent manner, while silencing Chemerin in senescent fibroblasts via siRNAs reduced cSCC migration. Chemerin was found to activate mitogen-activated protein kinase (MAPK) signaling pathway. Of note, inhibition of MAPK signaling pathway with chemical inhibitors impaired SASP-induced migration of cSCC cells in response to senescent fibroblast CM and rh Chemerin. In aggregate, these previously unreported data suggest that senescent fibroblasts may facilitate tumor progression through Chemerin-mediated activation of MAPK pathway in cSCC cells. 077 The role of intra-abdominal adipose tissue in UVB-induced skin cancer J Bernard and B Bullard Pharmacology and Toxicology, Michigan State University, East Lansing, MI Recent research suggests that a high-fat diet (HFD) and/or obesity (increased adiposity) are key players in the pathogenesis and prognosis of many common cancers. However the molecular changes induced by adipose tissue (AT) that actually enhance cancer development are poorly understood. Our previous studies indicated that decreasing visceral (intraabdominal) AT by surgical removal of the parametrial fat pads inhibited UVB-induced carcinogenesis in SKH-1 mice fed a HFD indicating that the parametrial AT from mice fed a HFD played a role in skin carcinogenesis. The purpose of this study was to investigate how a HFD may influence the intrinsic properties of the parametrial AT to induce UVB-induced skin tumor formation. We developed a system where molecules released and filtered from AT (fat tissue filtrate) stimulate JB6 P cell proliferation and transformation. The mouse BALB/c skin epithelial JB6 P cell line is a well-characterized model for neoplastic transformation that is responsive to tumor promoter-induced transformation growth in soft agar and is uniquely suited for studying tumor promotion and promotion-relevant molecular events in vitro. Our data demonstrate that fat tissue filtrate made from the parametrial ATof obese mice fed a HFD had 160% more transforming activity than that from mice fed a LFD (P

Microplasma sources typically take advantage of pd (pressure × size) scaling by increasing pressure to operate at dimensions as small as tens of microns. In many applications, low pressure operation is desirable, which makes miniaturization difficult. In this paper, the characteristics of low pressure microplasma sources excited by microwave power are discussed based on results from experimental and computational studies. The intended application is production of VUV radiation for chemical analysis, and so emphasis in this study is on the production of resonant excited states of rare gases and radiation transport. The systems of interest operate at a few to 10 Torr in Ar and He/Ar mixtures with cavity dimensions of hundreds of microns to 1 mm. Power deposition is a few watts which produces fractional ionization of about 0.1%. We found that production of VUV radiation from argon microplasmas at 104.8 nm and 106.7 nm saturates as a function of power deposition due to a quasi-equilibrium that is established between the electron temperature (that is not terribly sensitive to power deposition) and the population of the Ar(4s) manifold.

A laser initiation and radio frequency (rf) sustainment technique has been developed and improved from our previous work to create and sustain large-volume, high-pressure air and nitrogen plasmas. This technique utilizes a laser-initiated, 15 mTorr partial pressure tetrakis (dimethylamino) ethylene seed plasma with a 75 Torr background gas pressure to achieve high-pressure air/nitrogen plasma breakdown and reduce the rf power requirement needed to sustain the plasma. Upon the laser plasma initiation, the chamber pressure is raised to 760 Torr in 0.5 s through a pulsed gas valve, and the end of the chamber is subsequently opened to the ambient air. The atmospheric-pressure plasma is then maintained with the 13.56 MHz rf power. Using this technique, large-volume (1000 cm3), high electron density (on the order of 1011–12 cm−3), 760 Torr air and nitrogen plasmas have been created while rf power reflection is minimized during the entire plasma pulse utilizing a dynamic matching method. This plasma can project ...