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The potential of electrical impedance spectroscopy (EIS) was demonstrated for the investigation of microstructural properties of osseous tissue. Therefore, a deep neural network (DNN) was implemented for a sensitive assessment of different structural features that were derived on the basis of dielectric parameters, especially relative permittivities, recorded over a frequency range from 40 Hz to 5 MHz. The advantages of the developed method over conventional approaches, including equivalent circuit models (ECMs), linear regression and effective medium approximation (EMA), is the comprehensive quantification of bone morphologies by several microstructural parameters simultaneously, such as bone volume fraction (BV/TV), bone surface-volume-ratio (BS/BV), structure model index (SMI), trabecular number (Tb.N) and trabecular thickness (Tb.Th). The comparison of predictions of the DNN with an analysis of µCT-images confirmed a high accuracy for different microstructural parameters, which was indicated by corresponding Pearson correlation coefficients, especially for Tb.Th (r = 0.89) and BS/BV (r = 0.80). Concurrently, the approach was able to unambiguously discriminate anatomically similar bone regions (femoral head, greater trochanter and femoral neck) and therefore was capable to determine the morphological status of osseous tissue in detail. The classification was more discriminative than one based on classical linear discriminant analysis (LDA), due to the distinguishing features extracted by the DNN model. Accordingly, the method and model can serve as a potential tool for evaluating bone quality and bone status.

Elevated serum homocysteine, an intermediate of cellular one-carbon metabolism, is an independent risk factor for cardiovascular disease (CVD). Folate deficiency increases serum homocysteine and may contribute to CVD progression. Vascular smooth muscle cells (VSMCs) regulate vascular contractility, but also contribute to repair processes in response to vascular injury. Nutritional deficiencies, like folate deficiency, are thought to impact on this phenotypic plasticity, possibly by epigenetic mechanisms. We have investigated the effect of folate deficiency on VSMCs in two cell culture systems representing early and late stages of smooth muscle cells differentiation. We find that folate deficiency promotes differentiation towards a more contractile phenotype as indicated by increased expression of respective marker genes. However, microarray analysis identified markers of striated muscle as the predominant gene expression change elicited by folate deficiency. These changes are not merely a reflection of cell cycle arrest, as foetal calf serum restriction or iron deficiency do not replicate the gene expression changes observed in response to folate deficiency. Folate deficiency only has a marginal effect on global DNA methylation. DNA methylation of CpG islands associated with genes regulated by folate deficiency remains unaffected. This supports our earlier findings in a mouse model system which also did not show any changes in global DNA methylation in response to folate and vitamin B6/B12 deficiency. These data suggest that folate deficiency enhances the expression of smooth muscle marker gene expression, promotes a shift towards a skeletal muscle phenotype, and does not regulate gene expression via DNA methylation.

Low-temperature plasma with reactive species including the hydroxyl radical is found very effective for the degradation of many pharmaceuticals and macromolecular organic matter in wastewater. The most efficient way is to excite plasma directly in the wastewater using high-voltage sub-microsecond pulses which prevents the corona discharges developing into arc discharges. Recently, plasma generated with high-voltage pulses of only several hundred nanosecond durations has been found to be especially efficient. Therefore, an all solid-state sub-microsecond pulse generator prototype based on the Marx concept is constructed, with MOSFET power semiconductor devices. This pulse generator is able to generate rectangular pulses with adjustable durations in impedance-varying wastewater. The sub-microsecond signals are generated by field-programmable gate array, and simulations of the driving circuits are carried out to optimize the driving signals so as to trigger the switches synchronously in a few nanoseconds. First, experiments show that sub-microsecond pulses with amplitudes over 7 kV and a minimum pulse duration of about 100 ns can be generated. Both rise time and fall time are about 22 ns. Pulse frequency up to 30 kHz is achieved. Besides, most of these parameters can be adjusted. The pulse generator itself is compact and portable.

Objective We analyzed the outcomes for patients with a retropharyngeal internal carotid artery (ICA) who underwent a transoral robotic surgery (TORS) procedure involving a cervical-transoral robotic oropharyngectomy course with free flap reconstruction. Methods Patients were included in the prospective multicentric trial NCT02517125. These patients were scheduled to undergo surgery for an oropharyngeal localization. By pre-operative CT scan and MRI it was determined that they had a retropharyngeal internal carotid artery. Results Three patients had a retropharyngeal ICA: a patient with a 35 mm synovial sarcoma of the tonsillar fossa, a patient with a T2N2b squamous-cell carcinoma (SCC) of the glossotonsillar sulcus, and a patient with a T3N0 SCC of the tonsillar fossa in a previously irradiated field. These patients encountered neither preoperative nor postoperative complications. Conclusions In our experience, TORS for oropharyngeal cancers appears to be feasible in patients with a retropharyngeal ICA, provided that the procedure has been adapted for complex situations. Level of evidence 4.

Pulsed electrical discharges in water were used for nanostructuration of the polysilane-silicon quantum dots (SiQDs) composite dispersed in a cellulose acetate matrix. For this purpose, the polysilane-SiQDs composite was synthesized by chain scission of a poly[diphenyl-co-methyl(H)] oligomer in the presence of molten sodium and catalytic amounts of methyl(H) dichlorosilane. The resulting solid was utilized to prepare free standing thin films using the cellulose acetate matrix as support. Samples of these films were exposed to nanosecond pulsed electrical discharges in water. Through this approach, chemo-mechanical nanostructuration of specific silicon-based structures occurred by removing the excess of polysilane and by oxidative action. Fluorescence measurements of the plasma treated samples showed a higher intensity compared to the untreated ones. The elemental composition and the morphology of the film surface were investigated by TEM, XPS, UHR-SEM and AFM analysis. Such a technique represents a new approach toward a selective processing of the polysilane-SiQDs composite to obtain patterns with different optoelectronic properties on various supports.

Archaeological and geomorphological investigations of Little Bluff (47Tr32), in Trempealeau, Wisconsin, reveal how and, possibly, why this loess-capped sandstone ridge spur was anthropogenically altered in the mid-eleventh century A.D. Project excavation units and trenches dug in 2010–2011 revealed the timing, rate of completion, structure, symmetry, and orientation of the construction. In addition to delineating construction details and associated archaeological features, our research suggests that Cahokians, by sculpting and rebuilding this ridge spur, were actively positioning themselves vis-a-vis the wider Mississippi Valley landscape, if not the cosmos generally.

Nanosecond pulsed electric fields (nsPEFs) applied to cells can induce different biological effects depending on pulse duration and field strength. One known process is the induction of apoptosis whereby nsPEFs are currently investigated as a novel cancer therapy. Another and probably related change is the breakdown of the cytoskeleton. We investigated the elasticity of rat liver epithelial cells WB-F344 in a monolayer using atomic force microscopy (AFM) with respect to the potential of cells to undergo malignant transformation or to develop a potential to metastasize. We found that the elastic modulus of the cells decreased significantly within the first 8 min after treatment with 20 pulses of 100 ns and with a field strength of 20 kV/cm but was still higher than the elasticity of their tumorigenic counterpart WB-ras. AFM measurements and immunofluorescent staining showed that the cellular actin cytoskeleton became reorganized within 5 min. However, both a colony formation assay and a cell migration assay revealed no significant changes after nsPEF treatment, implying that cells seem not to adopt malignant characteristics associated with metastasis formation despite the induced transient changes to elasticity and cytoskeleton that can be observed for up to 1 h.

Gap junctional intercellular communication (GJIC) is an important mechanism that is involved and affected in many diseases and injuries. So far, the effect of nanosecond pulsed electric fields (nsPEFs) on the communication between cells was not investigated. An in vitro approach is presented with rat liver epithelial WB-F344 cells grown and exposed in a monolayer. In order to observe sub-lethal effects, cells were exposed to pulsed electric fields with a duration of 100 ns and amplitudes between 10 and 20 kV/cm. GJIC strongly decreased within 15 min after treatment but recovered within 24 h. Gene expression of Cx43 was significantly decreased and associated with a reduced total amount of Cx43 protein. In addition, MAP kinases p38 and Erk1/2, involved in Cx43 phosphorylation, were activated and Cx43 became hyperphosphorylated. Immunofluorescent staining of Cx43 displayed the disassembly of gap junctions. Further, a reorganization of the actin cytoskeleton was observed whereas tight junction protein ZO-1 was not significantly affected. All effects were field- and time-dependent and most pronounced within 30 to 60 min after treatment. A better understanding of a possible manipulation of GJIC by nsPEFs might eventually offer a possibility to develop and improve treatments.

This paper describes the effect of nanosecond pulsed electrical discharges generated in distilled water on cobalt-modified fluorinated polyimide (PI) films derived from hexafluoroisopropylidendiphthalic dianhydride and 4,4’-diamino-3,3’-dimethyl diphenylmethane. The PI films have been characterized by dielectric spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction (XRD) measurements. The relative permittivity of the PI films increased after treatment by water plasma. The XRD analysis has shown a slight increase of the degree of intermolecular ordering and stronger $\pi $ – $\pi $ interactions with the increase of the plasma treatment time. Application of nanosecond high-voltage pulses has induced an increase in concentration of CF3 groups at the polymer surface. A decrease of the cobalt and chlorine fractions, due to their migration into water, and an increase of aliphatic C–C bonds at the film surface may be responsible for the relative permittivity modification after exposure to water plasma.

Antigen-induced mast cell (MC) activation via cross-linking of IgE-bound high-affinity receptors for IgE (FcεRI) underlies type I allergy and anaphylactic shock. Comprehensive knowledge of FcεRI regulation is thus required. We have identified a functional interaction between FcεRI and CD13 in murine MCs. Antigen-triggered activation of IgE-loaded FcεRI results in cocapping and cointernalization of CD13 and equivalent internalization rates of up to 40%. Cointernalization is not unspecific, because ligand-driven KIT internalization is not accompanied by CD13 internalization. Moreover, antibody-mediated cross-linking of CD13 causes IL-6 production in an FcεRI-dependent manner. These data are indicative of a functional interaction between FcεRI and CD13 on MCs. To determine the role of this interaction, CD13-deficient bone marrow-derived MCs (BMMCs) were analyzed. Intriguingly, antigen stimulation of CD13-deficient BMMCs results in significantly increased degranulation and proinflammatory cytokine production compared to wild-type cells. Furthermore, in a low-dose model of passive systemic anaphylaxis, antigen-dependent decrease in body temperature, reflecting the anaphylactic reaction, is substantially enhanced by the CD13 inhibitor bestatin (-5.9 ± 0.6°C) and by CD13 deficiency (-8.8 ± 0.6°C) in contrast to controls (-1.2 ± 1.97°C). Importantly, bestatin does not aggravate anaphylaxis in CD13-deficient mice. Thus, we have identified CD13 as a novel negative regulator of MC activation in vitro and in vivo-Zotz, J. S., Wölbing, F., Lassnig, C., Kauffmann, M., Schulte, U., Kolb, A., Whitelaw, B., Müller, M., Biedermann, T., Huber, M. CD13/aminopeptidase N is a negative regulator of mast cell activation.

A universal strategy for the sensitive investigation of cell responses to external stimuli, in particular nanosecond pulsed electric fields (nsPEFs), was developed based on electrical impedance spectroscopy (EIS) in combination with a multi-peak analysis for the distribution of relaxation times (DRT). The DRT method provides high resolution for the identification of different polarization processes without a priori assumptions, as they are needed by more conventional approaches, such as an evaluation by equivalent circuit models. Accordingly, the physical properties of cells and their changes due to external stimuli can be uncovered and visualized and dispersion mechanisms introduced by Schwan et al. clearly identified. These are in particular relaxation processes at about 100 kHz that are associated with cell membrane characteristics and dominating respective changes of the distribution function for epithelial cell monolayers after exposure. A relatively moderate evolution at about 10 kHz may represent the polarization of extracellular matrices. Relaxation processes at around 1 MHz were suggested to be associated with intracellular changes. Conversely, the distribution of relaxation times can aid the optimization of the experimental design with respect to intended responses by an external stimulus.

Anthropogenic pollutants and in particular pharmaceutical residues are a potential risk for potable water where they are found in increasing concentrations. Different environmental effects could already be linked to the presence of pharmaceuticals in surface waters even for low concentrations. Many pharmaceuticals withstand conventional water treatment technologies. Consequently, there is a need for new water purification techniques. Advanced oxidation processes (AOP), and especially plasmas with their ability to create reactive species directly in water, may offer a promising solution. We developed a plasma reactor with a coaxial geometry to generate large volume corona discharges directly in water and investigated the degradation of seven recalcitrant pharmaceuticals (carbamazepine, diatrizoate, diazepam, diclofenac, ibuprofen, 17α-ethinylestradiol, trimethoprim). For most substances we observed decomposition rates from 45% to 99% for treatment times of 15-66 min. Especially ethinylestradiol and diclofenac were readily decomposed. As an inherent advantage of the method, we found no acidification and only an insignificant increase in nitrate/nitrite concentrations below legal limits for the treatment. Studies on the basic plasma chemical processes for the model system of phenol showed that the degradation is primarily caused by hydroxyl radicals.

Nanosecond high voltage pulses of 10 ns duration were used to generate pulsed discharges in distilled water for surface modifications of the aromatic and partially aromatic polyimides. Optical emission spectroscopy has shown the formation of excited speciesin plasma due to water dissociation and ionization. Molecular bands of hydrogen, oxygen, and nitrogen have dominated the emission spectra. The reactive species are likely to be responsible for the observed surface modifications of polymer films which were investigated by FTIR, AFM, XPS, and static contact angle measurements. The surface hydrophobicity of the polyimide films increased with treatment time. The mechanism of surface modification of polyimides treated by nanosecond pulsed discharges was different from previously described interactions with plasmas that were generated with microsecond voltage pulses. Nanosecond high voltage pulses have induced an increase of the unsaturated bondings on the polyimide surface, while the segregation of CF3 groups at the film surface was responsible for the increased surface hydrophobicity when discharges were generated with microsecond high voltage pulses.

Chemical species that are generated by a plasma jet in a microhollow cathode discharge geometry when operated with air and a dc voltage were investigated. Nitric oxide (NO) is found as the dominant long-lived reaction product with concentrations of several hundreds of ppm. In comparison, the concentrations observed for nitric dioxide (NO2) and ozone (O3) are negligible. The concentrations of NO are increasing with increasing electric power but decreasing with increasing flow rates. Simultaneously, NO2 concentrations are increasing slightly. The results suggest that the observed far reaching biocidal effect of the plasma jet depends on the generation of nitric oxide.

The efficient extraction of the rich amount of primary and secondary metabolites from microalgae has motivated considerable research. Besides biofuel production, microalgae are especially interesting as source for pharmaceutically and nutritionally valuable compounds. Major obstacle for economic down-streaming processes is the strong and rigid cell wall of microalgae, which impedes efficient compound extraction. Standard extraction methods suffer from several disadvantages and hence, alternative techniques are needed. Especially techniques, which do not modify components and are suitable for thermolabile compounds are required. Microwave burst exposures and submerged spark plasmas have been shown to lead to the release of higher protein yields than other methods. For comparison, Chlorella vulgaris was chosen as model organism because of its particular strong cell wall. Shotgun proteomics revealed comparable results of both methods, though several protein groups of interest showed differences in label-free quantification. Peptide modifications caused by reactive oxygen and nitrogen species (RONS) were observed after spark plasma treatment. However, spark discharges have been found more suitable for the extraction of heat sensitive compounds, such as photosystem-related proteins or histones.

B-vitamin deficiency is a risk factor for vascular disease. The mechanism by which the deficiency impacts on disease risk is unclear. We have analysed whether the inflammatory response of mononuclear cells can be modified by cellular folate status in vitro. We show that the mouse monocyte cell line RAW264.7 grown under folate restriction displays a decrease in intracellular folate levels and a reduced growth rate. The cells also show a 2- to 3-fold increase in expression of the inflammatory mediators, IL1β, IL6, TNFα and MCP1 at the RNA and protein level (p

Early malnutrition is a highly prevalent condition in developing countries. Different rodent models of postnatal early malnutrition have been used to approach the subject experimentally, inducing early malnutrition by maternal malnutrition, temporal maternal separation, manipulation of litter size or the surgical nipple ligation to impair lactation. Studies on the behaviour of (previously) malnourished animals using animal models have produced sometimes contradictory results regarding the effects of early postnatal malnutrition and have been criticized for introducing potential confounding factors. The present paper is a first report on the behavioural effects of early malnutrition induced by an alternative approach: mice nursed by α-casein-deficient knockout dams showed a severe growth delay during early development and substantial catch-up growth after weaning when compared with animals nursed by wild-type females.Established behavioural tests were used to study the consequences of early postnatal malnutrition on mouse pups at weaning and after partial weight recovery.Despite the impaired growth, the only behavioural difference between malnourished and normally growing animals was found in exploratory behaviour during acute malnutrition at the time of weaning. After partial catch-up in weight early protein malnourished animals showed no indication of lasting effects on general activity, emotionality and exploration, memory, and pain reactivity.These results suggest that the role of early nutrition on behavioural development after recovery in animal models may have been overestimated. Further careful examination of this animal model in terms of maternal care and offspring behaviour will be necessary to confirm if mice nursed by α-casein-deficient dams offer an alternative to existing models while eliminating potential confounding factors.

A plasma jet operated with atmospheric pressure air is presented. Unlike the dynamics of plasma jets working with noble gases, the propagation of the jet that is operated with air is primarily determined by the gas flow. This jet can be generated by applying a continuous, i.e., DC high voltage. However, depending on the applied voltage and gas flow rate a true DC operation can be distinguished from a self-pulsing mode. The gas temperature of the plasma plume when operated in the pulsed mode is lower than for the DC mode. Conversely, emission intensities of atomic oxygen, O, and nitrogen species, N 2 and N + 2 , are much higher for the pulsed mode than observed for DC operation.

Geriatric medicine is one of the most rapidly growing medical subspecialties as a response to demographic changes seen in all western societies. One of the main problems of all aging populations is the increase in incidence and severity of comorbidities. Three epidemiological types of (co)morbidities can be identified: (1) Cardiac and vascular diseases including risk factors like diabetes mellitus, (2) malignancies of the elderly and (3) cognitive impairments defined as dementia. These epidemiologic-medical classes need different strategies. The first morbidity type is addressed by preventive medicine and modern therapy with great successes in recent years. In contrast, malignant diseases are continuously increasing in the elderly cohort, but a variety of new therapeutic measure shave turned some previously fatal disorders into chronic ones. In contrast, neither preventive nor therapeutic measures are available for dementia. Our response is better care and support, which demands specialized human resources that are becoming scarce. Better training of more individuals to care for elderly is a great challenge for our society.

We evaluated a nonthermal plasma jet for a respective use to prevent infections from bacteria and yeasts. The plasma jet is generated from the flow of ambient air with 8 slm through a microhollow cathode discharge assembly that is operated with a direct current of 30 mA. With these parameters, the temperature in the jet reaches 43 °C at 10 mm from the discharge. Agar plates that were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Candida kefyr were treated at this distance, moving the plates through the jet in a meander that covered a 2 cm by 2 cm area. Different exposure times were realized by changing the speed of the movement and adjusting the distance between consecutive passes. S. aureus was most responsive to the exposure with a reduction in the number of colony forming units of 5.5 log steps in 40 s. All other microorganisms show a more gradual inactivation with exposure times. For all bacteria, a clearing of the treated area is achieved in about 2.5-3.5 min, corresponding to log-reduction factors of 5.5-6.5. Complete inactivation of the yeast requires about 7 min. Both S. aureus and C. kefyr show considerable inactivation also outside the immediate treatment area, while P. aeruginosa and A. baumannii do not. We conclude that differences in the morphologies of the membrane structures are responsible for the diverging results, together with a targeted response to different agents provided with the plasma jet. For the gram negative bacteria, we hold short-lived agents, acting across a short range, responsible, while for the other microorganisms, longer lived species seem more important. Our measurements show that neither heat, ultraviolet radiation, nor the generation of ozone can be responsible for the observed results. The most prominent long lived reaction product found is nitric oxide, which, by itself or through induced chemical reactions, might affect cell viability.

We have investigated the temporal evolution of the dielectric properties of Jurkat cells, a malignant human T-cell line, after exposure to microsecond and nanosecond pulsed electric fields. Suspensions with a 10% volume fraction of Jurkat cells were exposed to either 8 consecutive 1.1 kV/cm electroporation pulses of 100 μs, or 8 consecutive 20-kV/cm pulses of 300 ns, applied with a repetition rate of about 1 Hz. The dielectric spectrum of the cell suspensions before and after exposure was determined by means of time domain reflectometry dielectric spectroscopy. After correction for electrode polarization, the conductivity and permittivity of the cell membrane was derived by fitting the suspension spectrum to a combination of Maxwell-Wagner mixture model and single-shell cell model. Both exposure regimens lead to an increase in the conductivities of suspending medium and cell membrane indicating that membrane poration had occurred. This was confirmed by membrane integrity markers. Significantly higher membrane conductivities without uptake of membrane integrity marker suggest different pore formation mechanisms. Accordingly, dielectric measurements allow us to assess conformational and possibly induced functional changes of cells after exposure on biologically relevant time scales, and in turn, evaluate and compare the efficacy of chosen pulse parameters.

Gemas einem Modell nach Balducci verschiebt sich die Stammzellreserve im Alter vom „ruhenden“, selbstreproduzierenden Pool zum proliferierenden Pool, entsprechend den hoheren Anforderungen zur Gewahrleistung der immunologischen Homoostase und Infektabwehr. „Hamatopoetischer Stress“ jeder Art, z. B. bei einer Sepsis oder einer zytoreduktiven Chemotherapie, fuhrt zu einer Verminderung der peripheren Stammzellzahl bei Alteren im Gegensatz zu einem Anstieg bei Jungeren. Diese Veranderungen sind etwa ab dem 70. Lebensjahr physiologisch relevant. Zusatzlich kommt es auch zu einer Anderung der Granulozytenfunktion, speziell ihrer phagozytaren Kapazitat, sowie der Balance zwischen stimulierenden und hemmenden Zytokinen. Bestehende Komorbiditaten beeinflussen das Ausmas von Leukopenie und febriler Septikamie. Die prophylaktische Gabe von myelopoetischen Wachstumsfaktoren wird deshalb fur altere Patienten empfohlen, sobald das Risiko fur eine hohergradige Hamatotoxizitat (Grad III oder IV nach WHO-Kriterien) erwartet wird. Bislang existieren keine prognostischen Tests, die das individuelle Risiko der Hamatotoxizitat vorhersagen konnen.

Nitric oxide (NO) conversion has been studied for two different types of atmospheric-pressure pulsed-corona discharges, one generates a surface-plasma and the other provides a volume-plasma. For both types of discharges the energy cost for NO removal increases with decreasing oxygen concentration and initial concentration of NO. However, the energy cost for volume plasmas for 50% NO removal, EC50, from air was found to be 120 eV/molecule, whereas for the surface plasma, it was only 70 eV/molecule. A smaller difference in energy cost, but a higher efficiency for removal of NO was obtained in a pure nitrogen atmosphere, where NO formation is restricted due to the lack of oxygen. For the volume plasma, EC50 in this case was measured at 50 eV/molecule, and for the surface plasma it was 40 eV/molecule. Besides the higher NO removal efficiency of surface plasmas compared to volume plasmas, the energy efficiency of surface-plasmas was found to be almost independent of the amount of electrical energy deposited in the discharge, whereas the efficiency for volume plasmas decreases considerably with increasing energy. This indicates the possibility of operating surface plasma discharges at high energy densities and in more compact reactors than conventional volume discharges.

We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and stabilize DNA to the nuclear membrane, are severely compromised as measured by a pan-telomere probe. Internal pore formation following nsPEF applications has been described as a factor in induced cell death. Here we suggest that nsPEF induced physical changes to the cell in addition to pore formation need to be considered as an alternative method of cell death. We suggest nsPEF electrochemical induced depolymerization of actin filaments may account for cytoskeleton and nuclear membrane anomalies leading to sensitization.

The initial effect of nanosecond pulsed electric fields (nsPEFs) on cells is a change of charge distributions along membranes. This first response is observed as a sudden shift in the plasma transmembrane potential that is faster than can be attributed to any physiological event. These immediate, yet transient, effects are only measurable if the diagnostic is faster than the exposure, i.e., on a nanosecond time scale. In this study, we monitored changes in the plasma transmembrane potential of Jurkat cells exposed to nsPEFs of 60 ns and amplitudes from 5 to 90 kV/cm with a temporal resolution of 5 ns by means of the fast voltage-sensitive dye Annine-6. The measurements suggest the contribution of both dipole effects and asymmetric conduction currents across opposite sides of the cell to the charging. With the application of higher field strengths the membrane charges until a threshold voltage value of 1.4-1.6 V is attained at the anodic pole. This indicates when the ion exchange rates exceed charging currents, thus providing strong evidence for pore formation. Prior to reaching this threshold, the time for the charging of the membrane by conductive currents is qualitatively in agreement with accepted models of membrane charging, which predict longer charging times for lower field strengths. The comparison of the data with previous studies suggests that the sub-physiological induced ionic imbalances may trigger other intracellular signaling events leading to dramatic outcomes, such as apoptosis.

The application of gas discharge plasmas has assumed an important place in many manufacturing processes. Plasma methods contribute significantly to the economic prosperity of industrialized societies. However, plasma is mainly an enabling method and therefore its role remains often hidden. Hence the success of plasma technologies is described for different examples and commercial areas. From these examples and emerging applications, the potential of plasma technologies is discussed. Economic trends are anticipated together with research needs. The community of plasma scientists strongly believes that more exciting advances will continue to foster innovations and discoveries in the first decades of the 21st century, if research and education will be properly funded and sustained by public bodies and industrial investors.

Exposures to nanosecond pulsed electric fields (nsPEFs) are known to induce intracellular responses, such as the induction of apoptosis, offering a promising new method to treat cancer. This and other secondary biological responses are believed to be promoted by an initial formation of nanopores in cellular membranes. The primarily responsible charging mechanisms depend on pulse duration and amplitude, as well as the conductivity of the extracellular medium. In comparison, the postexposure development of membrane integrity and secondary-cell responses depend on complex interaction of biophysical and biochemical processes. To assess the effect of exposure media beyond their electrical characteristics, we studied different exposure media with similar conductivities and osmolalities. Experiments were performed using a typical nsPEF regimen, as is used in apoptosis studies (eight pulses of 60-ns duration and 60 kV/cm). We investigated the development of membrane permeability with propidium iodide and cell survival with calcein-AM on biologically relevant times out to 20 or 90 min, respectively. We found a tenfold increase in permeabilization of the plasma membrane depending on the exposure medium and a similar effect on the cell viability. The results suggest that progression of membrane permeability and cell survival strongly depend on the composition of the extracellular medium, rather than its electrical characteristic alone.

Micro-plasma jets in atmospheric pressure molecular gases (nitrogen, oxygen, air) were generated by blowing these gases through direct current microhollow cathode discharges (MHCDs). The tapered discharge channel, drilled through two 100 to 200 μm thick molybdenum electrodes separated by a 200 μm thick alumina layer, is 150 to 450 μm in diameter in the cathode and has an opening of 100 to 300 μm in diameter in the anode. Sustaining voltages are 400 to 600 V, the maximum current is 25 mA. The gas temperature of the microplasma inside the microhollow cathode varies between ~2000 K and ~1000 K depending on current, gas, and flow rate. Outside the discharge channel the temperature in the jet can be reduced by manipulating the discharge current and the gas flow to achieve values close to room temperature. This cold microplasma jet can be used for surface treatment of heat sensitive substances, and for sterilization of contaminated areas.

Many effective anti-cancer strategies target apoptosis and angiogenesis mechanisms. Applications of non-ionizing, nanosecond pulsed electric fields (nsPEFs) induce apoptosis in vitro and eliminate cancer in vivo; however in vivo mechanisms require closer analysis. These studies investigate nsPEF-induced apoptosis and anti-angiogenesis examined by fluorescent microscopy, immunoblots, and morphology. Six hours after treatment with one hundred 300 ns pulses at 40 kV/cm, cells transiently expressed active caspases indicating that caspase-mediated mechanisms. Three hours after treatment transient peaks in Histone 2AX phosphorylation coincided with terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells and pyknotic nuclei, suggesting caspase-independent mechanisms on nuclei/DNA. Large DNA fragments, but not 180 bp fragmentation ladders, were observed, suggesting incomplete apoptosis. Nevertheless, tumor weight and volume decreased and tumors disappeared. One week after treatment, vessel numbers, vascular endothelial growth factor (VEGF), platelet derived endothelial cell growth factor (PD-ECGF), CD31, CD35 and CD105 were decreased, indicating anti-angiogenesis. The nsPEFs activate multiple melanoma therapeutic targets, which is consistent with successes of nsPEF applications for tumor treatment in vivo as a new cancer therapeutic modality.

Nanosecond pulsed electric fields (nsPEFs) can affect the intracellular structures of cells in vitro. This study shows the direct effects of nsPEFs on tumor growth, tumor volume, and histological characteristics of normal skin and B16-F10 melanoma in SKH-1 mice. A melanoma model was set up by injecting B16-F10 into female SKH-1 mice. After a 100-pulse treatment with an nsPEF (40-kV/cm field strength; 300-ns duration; 30-ns rise time; 2-Hz repetition rate), tumor growth and histology were studied using transillumination, light microscopy with hematoxylin and eosin stain and transmission electron microscopy. Melanin and iron within the melanoma tumor were also detected with specific stains. After nsPEF treatment, tumor development was inhibited with decreased volumes post-nsPEF treatment compared with control tumors (P< 0.05). The nsPEF-treated tumor volume was reduced significantly compared with the control group (P < 0.01). Hematoxylin and eosin stain and transmission electron microscopy showed morphological changes and nuclear shrinkage in the tumor. Fontana–Masson stain indicates that nsPEF can externalize the melanin. Iron stain suggested nsPEF caused slight hemorrhage in the treated tissue. Histology confirmed that repeated applications of nsPEF disrupted the vascular network. nsPEF treatment can significantly disrupt the vasculature, reduce subcutaneous murine melanoma development, and produce tumor cell contraction and nuclear shrinkage while concurrently, but not permanently, damaging peripheral healthy skin tissue in the treated area, which we attribute to the highly localized electric fields surrounding the needle electrodes.

Physical mechanisms for streamer initiation and electrical breakdown in water are discussed. The focus is on various processes that could lead to the inception and propagation of streamers in water. Physical details associated with observed disparities in breakdown at the anode versus the cathode, differences in luminosity, and variations in streamer propagation speeds are discussed. Creation of a localized low-density region near the site of a field enhancement is shown to be essential for streamer initiation. Finally, the use of a trigatron-type electrically triggered switch with a triple-point geometry is shown to be a low-cost, compact alternative to laser (or acoustic) switching. Such controlled breakdown could be used for various applications including water purification and bio-decontamination.

Changes in [Ca 2+ ] i response of individual Jurkat cells to nanosecond pulsed electric fields (nsPEFs) of 60 ns and field strengths of 25, 50, and 100 kV/cm were investigated. The magnitude of the nsPEF-induced rise in [Ca 2+ ] i was dependent on the electric field strength. With 25 and 50 kV/cm, the [Ca 2+ ] i response was due to the release of Ca 2+ from intracellular stores and occurred in less than 18 ms. With 100 kV/cm, the increase in [Ca 2+ ] i was due to both internal release and to influx across the plasma membrane. Spontaneous changes in [Ca 2+ ] i exhibited a more gradual increase over several seconds. The initial, pulse-induced [Ca 2+ ] i response initiates at the poles of the cell with respect to electrode placement and co-localizes with the endoplasmic reticulum. The results suggest that nsPEFs target both the plasma membrane and subcellular membranes and that one of the mechanisms for Ca 2+ release may be due to nanopore formation in the endoplasmic reticulum.