Medical use of (non-)thermal plasmas is an emerging field in gynaecology. However, data on plasma energy dispersion remain limited. This systematic review presents an overview of plasma devices, ...fields of effective application, and impact of use factors and device settings on tissues in the female pelvis, including the uterus, ovaries, cervix, vagina, vulva, colon, omentum, mesenterium, and peritoneum. A search of the literature was performed on 4 January 2023 in the Medline Ovid, Embase, Cochrane, Web of Science, and Google Scholar databases. Devices were classified as plasma-assisted electrosurgery (ES) using electrothermal energy, neutral argon plasma (NAP) using kinetic particle energy, or cold atmospheric plasma (CAP) using non-thermal biochemical reactions. In total, 8958 articles were identified, of which 310 were scanned, and 14 were included due to containing quantitative data on depths or volumes of tissues reached. Plasma-assisted ES devices produce a thermal effects depth of <2.4 mm. In turn, NAP effects remained superficial, <1.0 mm. So far, the depth and uniformity of CAP effects are insufficiently understood. These data are crucial to achieve complete treatment, reduce recurrence, and limit damage to healthy tissues (e.g., prevent perforations or preserve parenchyma). Upcoming and potentially high-gain applications are discussed, and deficits in current evidence are identified.
Herein, we report a novel carbothermal welding strategy to prepare atomically dispersed Pd sites anchored on a three-dimensional (3D) ZrO2 nanonet (Pd1@ZrO2) via two-step pyrolysis, which were ...evolved from isolated Pd sites anchored on linker-derived nitrogen-doped carbon (Pd1@NC/ZrO2). First, the NH2–H2BDC linkers and Zr6-based Zr6(μ3-O)4(μ3-OH)412+ nodes of UiO-66-NH2 were transformed into amorphous N-doped carbon skeletons (NC) and ZrO2 nanoclusters under an argon atmosphere, respectively. The NC supports can simultaneously reduce and anchor the Pd sites, forming isolated Pd1–N/C sites. Then, switching the argon to air, the carbonaceous skeletons are gasified and the ZrO2 nanoclusters are welded into a rigid and porous nanonet. Moreover, the reductive carbon will result in abundant oxygen (O*) defects, which could help to capture the migratory Pd1 species, leaving a sintering-resistant Pd1@ZrO2 catalyst via atom trapping. This Pd1@ZrO2 nanonet can act as a semi-homogeneous catalyst to boost the direct synthesis of indole through hydrogenation and intramolecular condensation processes, with an excellent turnover frequency (1109.2 h–1) and 94% selectivity.
New occurrences of early artefacts ascribed to the Oldowan tradition come from localities at high level within the caldera of the extinct Kilombe volcano, located in the central rift valley of Kenya. ...The trachyte cone and caldera of Kilombe volcano formed at ca. 2.5 Ma, and the record of >130m of sediment-fill indicates that the caldera subsequently held a lake for long periods during the Early Pleistocene. The Oldowan artefact localities, dated by 40Ar/39Ar and palaeomagnetism to ∼1.78 Ma, lie east of the centre of the caldera, on the west side of an ancient small lake, which later drained away as a gorge formed on the east side of the mountain. The artefacts are dominantly made of Kilombe trachyte, and are associated with a fauna of large animals including Hippopotamus gorgops. These are the first Oldowan localities to be discovered in a new area of the Kenyan rift valley in the last thirty years, and their presence at high level in rugged landscape indicates that the associated hominins were exploiting a full range of environments.
De nouvelles occurrences d’artefacts anciens attribués à la tradition Oldowayenne proviennent de localités situées à un niveau élevé de la caldeira du volcan éteint de Kilombe, situé dans la vallée centrale du Rift au Kenya. Le cône de trachyte et la caldeira du volcan Kilombe se sont formés à ca. 2,5 Ma, et la séquence de plus de 130m de remplissage de sédiments indique qu’un lac occupait ensuite la caldeira pendant de longues périodes au cours du Pléistocène inférieur. Les sites d’artefacts oldowayens, datés par 40Ar/39Ar et du paléomagnétisme à ∼1,78 Ma, se trouvent à l’est du centre de la caldeira, sur le côté ouest d’un ancien petit lac, qui s’est ensuite drainé grâce a la formation d’une gorge sur le côté est de la montagne. Les artefacts sont principalement constitués de trachyte de Kilombe et sont associés à une faune de grands animaux, dont Hippopotamus gorgops. Ce sont les premières localités oldowayennes à être découvertes dans une nouvelle zone de la vallée du Rift kenyan au cours des trente dernières années, et leur présence à un niveau élevé dans un paysage accidenté indique que les hominidés associés exploitaient une gamme complète d’environnements.
Non-thermal (low-temperature) physical plasma is under intensive study as an alternative approach to control superficial wound and skin infections when the effectiveness of chemical agents is weak ...due to natural pathogen or biofilm resistance. The purpose of this study was to test the individual susceptibility of pathogenic bacteria to non-thermal argon plasma and to measure the effectiveness of plasma treatments against bacteria in biofilms and on wound surfaces. Overall, Gram-negative bacteria were more susceptible to plasma treatment than Gram-positive bacteria. For the Gram-negative bacteria Pseudomonas aeruginosa, Burkholderia cenocepacia and Escherichia coli, there were no survivors among the initial 10(5) c.f.u. after a 5 min plasma treatment. The susceptibility of Gram-positive bacteria was species- and strain-specific. Streptococcus pyogenes was the most resistant with 17 % survival of the initial 10(5) c.f.u. after a 5 min plasma treatment. Staphylococcus aureus had a strain-dependent resistance with 0 and 10 % survival from 10(5) c.f.u. of the Sa 78 and ATCC 6538 strains, respectively. Staphylococcus epidermidis and Enterococcus faecium had medium resistance. Non-ionized argon gas was not bactericidal. Biofilms partly protected bacteria, with the efficiency of protection dependent on biofilm thickness. Bacteria in deeper biofilm layers survived better after the plasma treatment. A rat model of a superficial slash wound infected with P. aeruginosa and the plasma-sensitive Staphylococcus aureus strain Sa 78 was used to assess the efficiency of argon plasma treatment. A 10 min treatment significantly reduced bacterial loads on the wound surface. A 5-day course of daily plasma treatments eliminated P. aeruginosa from the plasma-treated animals 2 days earlier than from the control ones. A statistically significant increase in the rate of wound closure was observed in plasma-treated animals after the third day of the course. Wound healing in plasma-treated animals slowed down after the course had been completed. Overall, the results show considerable potential for non-thermal argon plasma in eliminating pathogenic bacteria from biofilms and wound surfaces.
Semi-systematic and even trivial names are commonly used by the chemical community because of complicity of systematic names. But the differences between the expected and the actual composition are ...surprising in most cases. In this article, which is Part 1 (of a planned 4 articles), we consider elements from hydrogen (H) to argon (Ar) (Z = 1 to 18) and related compounds chosen for phonetic similarity of sound. A brief overview of the chemical energetics, most generally the enthalpy of formation, is given.
•The pore structure characteristics of coals were measured by the LP-N2GA and LP-ArGA.•The different properties are reflected in the pore structure parameters obtained by the LP-N2GA and ...LP-ArGA.•Fractal characteristics are used to analyze pore complexity and the roughness.
The accurate characterization of coal pore structure is of great significance for in-depth understanding of interior properties and gas adsorption, desorption and diffusion characteristics. In this study, the low pressure argon adsorption (LP-ArGA) and low pressure nitrogen adsorption (LP-N2GA) were all used to analyze the pore parameters of coal with different metamorphism. The results indicated that the adsorption isotherm type and desorption hysteresis type of coal samples obtained by the LP-ArGA and LP-N2GA belong to the same type, but the adsorption capacity of the former is higher than that of the latter. The pore size distribution (PSD) of coal samples shows a significant multi-peak distribution feature. Compared with the LP-N2GA, the LP-ArGA can accurately analyze the pore parameters between 2 and 4 nm or part of 2–7 nm. The mesopore volumes obtained by the LP-ArGA is 1.66–2.84 times that of the LP-N2GA, and there is no obvious law of macropore volume. The macropore volumes of QN and PM samples decreased by 17.2% and 50.9%, respectively, while GHS sample increased by 166.0%. The corresponding specific surface area (SSA) showed the same properties. Fractal curve fitting results obtained by the two methods are highly correlated, but compared with LP-ArGA, D1 and D2 obtained by the LP-N2GA can well reflect pore characteristics. The fractal dimension obtained by the two methods and the variation trend with the metamorphic degree are all different, which is mainly due to the difference of adsorption volume. The purpose of this paper is to introduce a new method for the analysis of coal pore structure in order to better understand the pore characteristics.
Fluids trapped as inclusions within minerals can be billions of years old and preserve a record of the fluid chemistry and environment at the time of mineralization. Aqueous fluids that have had a ...similar residence time at mineral interfaces and in fractures (fracture fluids) have not been previously identified. Expulsion of fracture fluids from basement systems with low connectivity occurs through deformation and fracturing of the brittle crust. The fractal nature of this process must, at some scale, preserve pockets of interconnected fluid from the earliest crustal history. In one such system, 2.8 kilometres below the surface in a South African gold mine, extant chemoautotrophic microbes have been identified in fluids isolated from the photosphere on timescales of tens of millions of years. Deep fracture fluids with similar chemistry have been found in a mine in the Timmins, Ontario, area of the Canadian Precambrian Shield. Here we show that excesses of (124)Xe, (126)Xe and (128)Xe in the Timmins mine fluids can be linked to xenon isotope changes in the ancient atmosphere and used to calculate a minimum mean residence time for this fluid of about 1.5 billion years. Further evidence of an ancient fluid system is found in (129)Xe excesses that, owing to the absence of any identifiable mantle input, are probably sourced in sediments and extracted by fluid migration processes operating during or shortly after mineralization at around 2.64 billion years ago. We also provide closed-system radiogenic noble-gas ((4)He, (21)Ne, (40)Ar, (136)Xe) residence times. Together, the different noble gases show that ancient pockets of water can survive the crustal fracturing process and remain in the crust for billions of years.
The protonated argon ion, {sup 36}ArH{sup +}, was recently identified in the Crab Nebula from Herschel spectra. Given the atmospheric opacity at the frequency of its J = 1-0 and J = 2-1 rotational ...transitions (617.5 and 1234.6 GHz, respectively), and the current lack of appropriate space observatories after the recent end of the Herschel mission, future studies on this molecule will rely on mid-infrared observations. We report on accurate wavenumber measurements of {sup 36}ArH{sup +} and {sup 38}ArH{sup +} rotation-vibration transitions in the v = 1-0 band in the range 4.1-3.7 μm (2450-2715 cm{sup –1}). The wavenumbers of the R(0) transitions of the v = 1-0 band are 2612.50135 ± 0.00033 and 2610.70177 ± 0.00042 cm{sup –1} (±3σ) for {sup 36}ArH{sup +} and {sup 38}ArH{sup +}, respectively. The calculated opacity for a gas thermalized at a temperature of 100 K and with a linewidth of 1 km s{sup –1} of the R(0) line is 1.6 × 10{sup –15} × N({sup 36}ArH{sup +}). For column densities of {sup 36}ArH{sup +} larger than 1 × 10{sup 13} cm{sup –2}, significant absorption by the R(0) line can be expected against bright mid-IR sources.
Aluminum microfoams are found to exhibit persistent sputtering yield reductions of 40%-80% compared to a flat aluminum surface under 100 to 300 eV argon plasma bombardment. An analytical model ...reveals a strong dependency of the yield on the foam geometry and plasma sheath. For foam pore sizes near or larger than the sheath thickness, the plasma infuses the foam and transitions the plasma-surface interactions from superficial to volumetric phenomena. By defining a plasma infusion parameter, the sputtering behavior of foams is shown to be separated into the plasma-facing and plasma-infused regimes. While plasma infusion leads to a larger effective sputtering area, geometric recapture of ejected particles facilitates an overall reduction in yield. For a given level of plasma infusion, the reductions in normalized yield are more pronounced at lower ion energies since angular sputtering effects enable more effective geometric recapture of sputterants.
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