A simple microcalorimetry system to determine the adsorption behaviour of acids in large adhesive bond gaps using base-initiated solution polymerisation of ethyl-2-cyanoacrylate

Eight patients with suspected cyanoacrylate contact allergy post-surgery underwent patch testing with an extended European baseline of contact allergens and a ‘mini’ acrylates series (Chemotechnique Diagnostics, Vellinge, Sweden, in IQ Ultra™ chambers). Additionally, patch testing with the surgical glues Dermabond® (2-octyl cyanoacrylate, Ethicon, New Jersey) or Histoacryl® (n-butyl cyanoacrylate, B. Braun Medical Ltd, Sheffield, UK), was performed, in the conventional manner for all eight cases, and with tape stripping before application for cases 4–8. Allergens were occluded for 2 days, with readings on days 2, 4 and 7 in line with European Society of Contact Dermatitis guidelines. Tape stripping was performed by applying adhesive tape (Sellotape®) uniformly, 20 times, on the upper arm, prior to the application of the cyanoacrylates. Five of the patients (case 1–5) had a negative or doubtful reaction on conventional patch testing to the skin adhesive despite strong clinical suspicion, two of whom were strongly positive at the tape strip testing sites (Table 1, Figure 1). Conversely, all cases where tape strip testing was performed were positive. Ethyl cyanoacrylate (ECA) was positive in five cases; only one patient had a history of prior reactions to glue used for artificial nails. Dermabond® (N) ECA (N) Lipofilling to left breast reconstruction closed with Dermabond® N.B. left mastectomy 2 years previously, complicated with infection requiring multiple surgical procedures Dermabond® (N) ECA (+++) Itchy, blistering eruption around incisions – 48 h post-surgery N.B. History of similar skin reactions with glues used with artificial nails Dermabond® (N) ECA (++) Dermabond® (N) ECA (N) Dermabond® (++) ECA not tested Histoacryl® (?+) ECA (?+) Histoacryl® (++) ECA (++) Dermabond® (+) ECA (+) Dermabond® (++) ECA (++) Battery change for sacral neuromodulator– closed with Dermabond® N.B. initial sacral neuromodulator fit 5 years previously- also closed with Dermabond® Dermabond® (+) ECA (+) Dermabond® (++) ECA (++) Dermabond® (++) ECA (N) Dermabond® (+++) ECA not tested Cyanoacrylates are commonly found in adhesives used in domestic and healthcare environments. ECA is found in eyelash glues and ‘superglues’. Topical skin adhesives (e.g., Dermabond®, Histoacryl®) are increasingly used for closure of small wounds. These are quick and easy to use, with a favourable cosmetic outcome compared with more traditional suturing.1, 2 They rapidly polymerize and bond to surface keratin, which is thought to prevent penetration beyond the stratum corneum, therefore avoiding antigen-presenting cells deeper in the epidermis.3 Both 2-octyl cyanoacrylate and n-butyl cyanoacrylate are not commercially available patch testing allergens. Tape stripping before patch testing is a modification which removes the stratum corneum barrier that limits hapten penetration. This increases bioavailability in the deeper epidermal layers and upper dermis, mimicking the use of cyanoacrylates during surgical procedures.2, 4 It is a less invasive method of removing the stratum corneum compared with scratch testing or skin abrasion. Dickel et al. have published a suggested method for strip patch testing, aiming to reach the stratum lucidum.4 In our case series, we used a standardized number of 20 applications of adhesive tape. In our cohort, it was user-friendly and efficient for the healthcare professionals, reproducible and well tolerated by all our patients. In four patients who tested positive to Dermabond® or, Histoacryl®, three reacted to ECA as well when tested. Potential cross-reactivity or co-sensitisation has previously been reported.2 In a larger study, just 29% of Dermabond-allergic patients had positive patch test reactions to ECA.5 Therefore, we consider it helpful to also test to ECA in patients with suspected 2-octyl or butyl cyanoacrylate allergy, but it may not be a sensitive enough marker when tested alone. This case series highlights the increased sensitivity of patch testing to cyanoacrylates by using the simple and pragmatic method of tape stripping prior to the application of the allergen. It is particularly useful for testing with the medical adhesives themselves where the suspected allergens are not commercially available. Ruchika Kumari: Writing – original draft; writing – review and editing; investigation; data curation; project administration. Analyn Gelvezon: Writing – review and editing; investigation; data curation; project administration. Ying X. Teo: Writing – review and editing; investigation; data curation; project administration. Louise Cunningham: Writing – review and editing; investigation; data curation; project administration. Sheila M. McSweeney: Investigation; data curation. John P. McFadden: Conceptualization; supervision. Ian R. White: Conceptualization; writing – review and editing; investigation; data curation; validation; supervision. The authors declare no conflicts of interest. Consent has been provided by all patients included for images to be used for publication.

Currently, cellulose is positioned as the most popular natural high-molecular biopolymer, the modification products of which are used to obtain materials such as composites, films, fibers, membranes, nanofibers, nanogels, hydrogels, etc., which are widely used in medicine: tissue engineering , as a drug delivery system; cell technology, as matrices for the immobilization of enzymes and biologically active substances, etc. The demand for biomedical materials based on cellulose is due to such unique properties as its biocompatibility with various tissues, non-toxicity, high crystallinity and mechanical strength, etc. The object of scientific research is esters - cellulose mesylates, obtained by the author of the project by chemical and electrochemical modification in methanesulfonic acid (MSA) solutions. The advantage of using methanesulfonic acid as a solvent and medium for modifying cellulose in comparison with toluenesulfonic acid is its low toxicity compared to other acids; biodegradability - in the natural environment, MSA is part of the cycle of organic sulfur circulation in nature and is destroyed with the formation of sulfur and carbon dioxides. It was found that the interaction of alcohol groups with the MSA molecules leads to the formation of esters - cellulose mesylates (MCC and NCC) and cellobiose. It is important to note that in the literature there are no scientific data on the modification of cellulose in MSA solutions. In this regard, this project proposes new methods of synthesis and study of the properties of biomedical materials based on cellulose mesylates and its derivatives.

To characterize the spatial distributions of methane‐sulfonic acid (MSA) as represented by measured aerosol methane sulfonate (MS) and its relationships with non‐sea‐salt (nss) sulfate (SO42−) in the marine atmospheric boundary layer over high‐latitude regions, bulk aerosol samples were collected during eight cruises during the Chinese National Antarctic and Arctic Research Expeditions from 1998 to 2008. The concentrations of MSA (an indicator of marine biogenic sulfur production), sulfate, sodium and chloride in samples were analyzed using ion chromatography. Increases in the aerosol MSA concentrations and MSA/nss‐SO42− ratios were observed as functions of latitudes in the Pacific Ocean, more abruptly near high southern latitudes as compared to those in high northern latitudes. The MSA concentrations increased from 0.011 μg m−3 near the equator to 0.26 μg m−3 at 63°S, 23°W and from 0.0013 μg m−3 at northern midlatitudes to 0.19 μg m−3 at 58°N, 175°E. However, MSA decreased in the latitudes north of 58°N in the Pacific, where air temperature was lower. MSA/nss‐SO42− ratios increased from 0.024 near the equator to 0.93 at 62°S, 4°E and from 0.0031 around northern midlatitudes to 0.39 at 68°N, 169°W. The MSA concentrations were more correlated with MSA/nss‐SO42− (R2 = 0.43, n = 60) in Southern Hemisphere than Northern Hemisphere (R2 = 0.091, n = 40). No significant correlation was found between MSA/nss‐SO42− and air temperature at high latitudes, indicating latitudinal temperature variations were not a main factor responsible for the MSA/nss‐SO42− variation in those regions. Substantial increases in the concentrations of MSA in coastal Antarctica may indicate additional sources of biogenic S besides the emissions of dimethylsulfide from the sea.

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core (20D). This study provides a high‐resolution record of the DMS‐derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb (σ = 2.38 ppb, n = 1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non‐sea‐salt sulfate (nss SO42−), which increases dramatically after 1900 due to the input of anthropogenic sulfur. The MSA fraction ((MSA/(MSA + nss SO42−))* 100) ranges from a mean of 15% in preindustrial ice to less than 5% in recent ice. These MSA fractions suggest that approximately 15 to 40% of the sulfur in recent Greenland ice is of biological origin. It is suggested that there is a significant low‐latitude component to the biogenic sulfur in the core and that variations in the MSA fraction reflect changes in the relative strengths of low‐ and high‐latitude inputs. The data show no evidence for a strong dependence of dimethyl sulfide (DMS) emissions on sea surface temperature during the last century. There is also no indication that the yield of MSA from DMS oxidation has been altered by increased NOx levels over the North Atlantic during this period.

Forty‐seven years of week‐long total suspended particle samples from Kevo Finland were analyzed for methane sulfonic acid (MSA) and sulfate. Kevo is located 350 km north of the Arctic Circle. MSA and non‐sea‐salt sulfate (NSS‐SO4) showed clear seasonal trends. MSA peaks from May to July, coinciding with warmer waters and increased biogenic activity in the surrounding seas. NSS‐SO4 peaks in March with a minimum during the summer, the typical pattern for Arctic haze. MSA concentrations were found to be positively correlated (p < 0.001) with sea surface temperature anomalies in the surrounding seas. MSA showed a trend of 0.405 ng/m3/yr (0.680%/yr) for June and July. NSS‐SO4 concentrations at Kevo declined dramatically in the early 1990s, probably as a result of the collapse of the Soviet Union. The decline has continued since the mid‐1990s.

A study on the improvement of deposition rate for near-eutectic PbSn solder plating was performed. This research focused on (1) the effect of process parameters on the diffusion-limited current density (LCD) to extend the operating zone, (2) the process optimization at 4 /spl mu/m/min with a modified bath, and (3) the trouble-shooting procedures for abnormal and non-conformal growths. The effect of waveform on surface morphology, growth pattern, film composition and thickness uniformity was also examined. The LCD was increased by increasing metal concentration, bath temperature and agitation, or by decreasing the concentration of methane sulfonic acid (MSA). The effect of additives on LCD was not significant. No significant change in morphology and growth pattern was observed up to approximately 10 /spl mu/m/min with a modified bath. Process results obtained at optimized conditions showed smooth surfaces, conformal growth and good repeatability of thickness and composition. The probability of abnormal growth was increased with increasing deposition rate, but it was prominently suppressed by increasing MSA concentration and temperature or by decreasing duty cycle. The growth conformality along the resist was improved at a fixed deposition rate by decreasing wafer rotation speed and duty cycle or by increasing MSA concentration.

Prospects of using poly(ethyl cyanoacrylate) as a carrier of antituberculosis drug capreomycin sulfate are considered. In vitro release of capreomycin sulfate from poly(ethyl cyanoacrylate) nanoparticles and degradation of polymer have been studied.

OBJECTIVES: The objectives of this study were to evaluate the apical sealing ability of four dental materials used in retrograde fillings. MATERIAL AND METHODS: Eighty human maxillary canines were selected and treated endodontically. The apical ends were sectioned and root-end cavities were prepared. The sample was randomly divided in four groups of 20 specimens each. In each group, root-end cavities were filled with one of the following materials: ethyl cyanoacrylate (EC); silver zinc freea amalgam (AM); resin-modified glass-ionomer cement (GIC); or resin-modified glass-ionomer cement and light curing (GIC+light). Specimens were immersed in 0.2% methylene blue for 24 hours at 37° C and then sectioned longitudinally. The analysis of dye penetration was conducted by means of visual inspection of the buccal and lingual sections of the roots. RESULTS: Analysis of variance was used to compare results. The least marginal leakage was found in the EC group, followed by the GIC+light, GIC and AM groups, which had the greatest leakage. CONCLUSION: In the conditions of this work, the use of GIC+light and EC provided the best apical sealing.

A green electrorefining process for production of pure lead from methanesulfonic acid medium

Successful matrix acidizing of carbonate reservoirs depends on the selection of optimal stimulation fluids. Because of the rapid reaction rate and corrosive nature of HCl in downhole conditions, other alternatives are much in demand. Organic acids, particularly methanesulfonic acid (MSA), offer a viable alternative to HCl in terms of being less reactive as well as less corrosive and environmentally benign. However, MSA is expensive. To reduce the cost, this study proposes to use blend of HCl and MSA for carbonate stimulation, while enhancing the properties of HCl. Coreflood studies were performed and the results were compared to those obtained by equivalent concentrations of the individual acids. Three different ratios of HCl and MSA were used to conduct coreflood experiments on 6-in. long Indiana Limestone cores at 250°F. The volume of acid required to reach breakthrough was recorded, and the cores were analyzed using CT scans. Wormhole structures were identified, and their tortuousities were determined. The effluent samples were analyzed for pH, calcium concentration, and unconsumed acid concentration. Coreflood studies indicated that 5:5 wt% HCl:MSA blend was the most suitable candidate for matrix acidizing among the three blends tested (2.5:7.5 and 7.5:2.5 wt% HCl:MSA being the other two blends investigated). At the optimum injection rate of 7.5 cm3/min, both 2.5:7.5 and 5:5 wt% HCl:MSA mixture required lesser pore volumes (PVs) of acid to reach breakthrough, compared to their individual acid controls. A single, straight, and dominant wormhole was observed with no branching and less tortuousity in both the cases. The control experiments with equivalent concentrations of HCl and MSA required higher PVs of acid to reach breakthrough with branching during wormhole propagation. Calcium ion dissolution was least for the 5:5 wt% mixture among the three blends tested. Higher unconsumed acid concentration was noted in case of 5:5 wt% compared to 2.5:7.5 wt% blend, thus promising greater penetration depth with the same PV of acid. On the other hand, the wormhole formed by the acid blend of 7.5:2.5 wt% HCl:MSA required almost the same PV of acid to reach breakthrough as its corresponding HCl control, and it was more enlarged and tortuous than its corresponding MSA control. 5:5 wt% HCl:MSA blend creates deeper wormholes and retards the HCl reaction with the rock matrix. Major advantages rendered by the new acid mixture include: (1) deeper wormholes that will ultimately result in enhanced well productivity, and (2) cost effectiveness in carbonate stimulation compared to standard systems currently used in the market.

<strong class="journal-contentHeaderColor">Abstract.</strong> The Arctic Ocean is continuously warming, resulting in sea ice retreat, which significantly impacts the marine biogenic sulfur cycle. The formation of aerosols from DMS oxidation and their climatic effects in the polar regions are of great concern. However, the impact of DMS chemistry on atmospheric aerosols in the high Arctic Ocean (AO) is still unclear due to the limitation of field observations and datasets. Gaseous methanesulfonic acid (MSA) and aerosol chemical species (MSA, SO₄^2- and DMA, etc.) were determined simultaneously with a high time resolution (1 hour) in the AO and Pacific Ocean (PO) to reveal the DMS chemistry in these regions. Extremely low MSA concentrations were observed in the high AO (75&deg;&ndash;85&deg; N), with an average of only 7.42 &plusmn; 6.60 ng&bull;m^-3. However, high MSA concentrations, with an average of 168.60 &plusmn; 167.60 ng&bull;m^-3 were observed in the mid-latitude regions (45&deg;&ndash;60&deg; N). Sea salt aerosols were the most dominant source in the high Arctic Ocean, accounting for 88.78 % of the total aerosols, which was much larger than the values in the other regions. The MSA fraction was much lower in the high latitude regions than in the other regions, accounting for only 1.61 % of the total aerosol particles. The latitudinal distribution of MSA was consistent with that of DMS over the AO. Low DMS chemistry was determined based on the low DMS emissions in the HL region. These results highlight the contribution of DMS chemistry to atmospheric aerosols and extend the knowledge of how biogenic aerosols impact the regional atmosphere in the high AO.

Oxygen evolution on alpha-lead dioxide electrodes in methanesulfonic acid

Electrochemical dissolution and recovery of tin from printed circuit board in methane–sulfonic acid solution

Methanesulfonic acid (MSA) is an atmospheric oxidation product of dimethyl sulfide, produced by marine biota. MSA preserved in a Svalbard glacier between 1920 and 1996 is compared with the sea surface temperature (SST) and sea‐ice extent of the surrounding ocean over the same period. On decadal timescales high MSA concentrations are found to be associated with warm SST and reduced sea‐ice extent. MSA appears to be influenced by climatic changes related to variations in the import of warm Atlantic Water to the Barents Sea. Atlantic Water plays an important role in the Arctic climate system, therefore MSA concentrations may indirectly reflect larger‐scale changes in the region and may be useful as a proxy for past climate.

Size‐segregated aerosol samples were collected over the western North Pacific in summer 2008 to investigate marine biological contribution to organic aerosols. The samples were analyzed for organic carbon (OC), water‐soluble organic carbon (WSOC), and water‐soluble organic compounds including diacids (C2–C9), ω‐oxocarboxylic acids, and α‐dicarbonyls as well as methanesulfonic acid (MSA). The average concentrations of OC and oxalic acid (C2) were approximately two to three times larger in marine biologically more influenced aerosols, defined by the concentrations of MSA and azelaic acid (C9), than in less influenced aerosols. WSOC, which showed a statistically significant correlation with MSA, accounted for 15–21% of total mass of the components determined in the submicrometer range of biologically more influenced aerosols. These values are comparable to those of water‐insoluble organic carbon (WIOC) (∼14–23%), suggesting that organic aerosols in this region are enriched in secondary organic aerosols (SOA) linked to oceanic biological activity. In these aerosols, substantial fractions of C2–C4 diacids were found in the submicrometer size range. Positive correlations of oxalic acid with C3–C5 diacids and glyoxylic acid suggest that secondary production of oxalic acid occurs possibly in the aqueous aerosol phase via the oxidation of longer‐chain diacids and glyoxylic acid in the oceanic region with higher biological productivity. We found similar concentration levels and size distributions of methylglyoxal between the two types of aerosols, suggesting that formation of oxalic acid via the oxidation of methylglyoxal from marine isoprene is insignificant in the study region.