PCDD/Fs, dioxin-like, and non-dioxin like PCBs in the sediments of high Arctic fjords, Svalbard.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are highly toxic organic compounds, and very few studies on their presence in polar environments have been conducted. This study assessed the concentration and distribution of PCDD/Fs, dioxin-like polychlorinated biphenyls (DL-PCBs), and non-dioxin-like polychlorinated biphenyls in selected fjords of the Svalbard archipelago in Norway. The ∑PCDD/Fs observed for Raudfjorden, Smeerenburgfjorden, Magdalenefjorden, and Kongsfjorden were 22.80 pg/g, 25.65 pg/g, 18.27 pg/g, 33.50 pg/g, and 21.69 pg/g, respectively. The WHO's toxic equivalents values of both ∑PCDD/Fs and ∑DL-PCBs were comparatively higher than those reported in other polar regions. Of the four fjords studied, the sediments from Kongsfjorden exhibited the presence of the most toxic materials, including PCB-126 and PCB-169, of DL-PCBs. More than 80% of the total analysed PCDD/Fs were comprised of highly chlorinated congeners (hexa-to-octa forms). More studies are required to understand the destination and transport of these hazardous pollutants in high Arctic sediments.

Mercury in the sediments of freshwater lakes in Ny-Ålesund, Arctic.

Mercury and its speciation in aquatic ecosystems have been assessed globally. Even though previous studies were limited to Arctic freshwater lakes, they are highly significant in the context of the changing climate. The present study is based on sediment samples collected from three Arctic freshwater lakes over a period of 4 years (2015-2018). The samples were analysed for total mercury (THg), methyl mercury (MHg), and various mercury fractions. The observed mean THg and MHg concentrations were 22.23 ng/g and 0.41 ng/g respectively; these values were comparable with those for other Arctic freshwater lakes. The mercury content significantly varied among the years as well as among the lakes. Changes in snowdrift and meltwater inputs, which are the major sources of water for the lakes, may have influenced the sediment mercury content along with geographical location and increased productivity. The results of MHg indicated the susceptibility of lake sediments to methylation. The major fractions observed were the organo-chelated form of mercury, followed by the elemental and water-soluble forms. These results indicate the availability of mercury for methylation. Hence, it is necessary to conduct more studies on the influence of climate change, mercury release through permafrost melting, and atmospheric deposition.

Rate of sediment accumulation and historic metal contamination in a tidewater glacier fjord, Svalbard.

The sedimentation rates in Arctic fjords are influenced by the changes in the glacial inputs. The recent studies have indicated the retreat of glaciers due to climate change and subsequent increase in melt water outflow with high content of debris. The debris may contain natural and anthropogenically originated contaminants. The present study analysed the sedimentation rate in inner Kongsfjorden, Ny-Ålesund, Svalbard using 210Pb/210Po dating technique. The sedimentation rate ranged between 0.22 and 0.37 cm/year during the last 112 years. The average sedimentation rate obtained was 0.28 cm/y. The rate has been increased during the last 20 years and it might be due to the increased influx of glacial melt water containing debris. Metals and other elements showed an increasing trend towards the surface and observed high deposition rate since 1970s, indicating influence of industrial emissions and it can be a potential threat to Arctic biota.

Distribution and fractionation of mercury in the soils of a unique tropical agricultural wetland ecosystem, southwest coast of India.

Mercury biogeochemistry is highly complex in the aquatic ecosystems and it is very difficult to predict. The speciation of mercury is the primary factor controlling its behavior, movement, and fate in these systems. The fluctuating water levels in wetlands could play a major role in the mercury transformations and transport. Hence, the agricultural wetlands may have a significant influence on the global mercury cycling. Kuttanad agricultural wetland ecosystem is a unique one as it is lying below the sea level and most of the time it is inundated with water. To understand the mobility and bioavailability of Hg in the soils of this agricultural wetland ecosystem, the present study analyzed the total mercury content as well as the different fractions of mercury. Mercury was detected using cold vapor atomic fluorescence spectrophotometer. The total mercury content varied from 0.002 to 0.683 mg/kg, and most of the samples are having concentrations below the background value. The percentage of mercury found in the initial three fractions F1, F2, and F3 are more available and it may enhance the methylation potential of the Kuttanad agroecosystem.

Shear bond strength evaluation of resin composite bonded to GIC using three different adhesives.

The current study evaluated the bonding ability of composite to glass ionomer cement (GIC) using three different bonding systems. One hundred samples of composites bonded to GIC were prepared and divided into five groups. In Group A, the composite was bonded to GIC after the initial setting of the GIC being employed as a total-etch adhesive. In Group B, the self-etch primer was employed to bond composite to GIC before the initial setting of the GIC. In Group C, the self-etch primer was employed to bond composite to the GIC after the initial setting of the GIC. In Group D, the GIC-based adhesive was employed to bond composite to the GIC before the initial setting of the GIC. In Group E, the GIC-based adhesive was employed to bond composite to the GIC after the initial setting of the GIC. Shear bond strength analysis was performed at a crosshead speed of 0.5 mm/minute. The results were tabulated and the statistical analysis was performed with one-way ANOVA; the Tukey's test showed that the bond strength of composite to GIC was significantly higher for the self-etch primer group employed on unset GIC and the GIC-based adhesive group employed on the set GIC for bonding composite to GIC.

Carpal tunnel syndrome: survey of an occupational hazard.

Carpal tunnel syndrome (CTS) is one of a number of muscle-tendon and nerve related disorders that affect people performing intensive work with their hands. Hand and wrist disorders are receiving most of the attention although their symptoms are reported less often by dental workers than symptoms of neck/back disorders. The lack of data pertaining to the behaviour of Indian general dental practitioners towards carpal tunnel syndrome was the basis behind this descriptive study to evaluate the prevalence of carpal tunnel syndrome symptoms.

Criteria for management of calcific metamorphosis: review with a case report.

Calcific metamorphosis is seen commonly in the dental pulp after traumatic tooth injuries and is characterized by deposition of hard tissue within the root canal space. Opinion differs among practitioners as to whether to treat these cases upon early detection of calcific metamorphosis or to observe them until symptoms or radiographic signs of pulpal necrosis are detected. In this article, the clinical, radiographic, and histopathologic appearance of calcific metamorphosis is described; a review of the literature is presented to address these issues in an attempt to establish sound rationale for treatment. Approximately 3.8% to 24% of traumatized teeth develop varying degrees of calcific metamorphosis. Studies indicate that of these, approximately 1% to 16% will develop pulpal necrosis. Most of the literature does not support endodontic intervention unless periradicular pathoses is detected or the involved tooth becomes syptomatic. It may be advisable to manage cases demonstrating calcific metamorphosis through observation and periodic examination. A report of a case where in non-surgical endodontic intervention was successfully carried out a patient suffering from calcific metamorphosis with periapical pathoses is also presented.

Effectiveness of prophylactic use of rofecoxib in comparison with ibuprofen on postendodontic pain.

The purpose of this study was to determine if prophylactic rofecoxib would significantly reduce postendodontic pain, when compared with ibuprofen or placebo. An additional objective was to establish if any relationship exists between periapical diagnosis and the need for additional medication after completion of pulpectomy. A total of 45 patients consented to a double-blind, single-dose oral administration of 50 mg of rofecoxib, 600 mg of ibuprofen, or a placebo before conventional root canal therapy. The root canal treatment was performed in two appointments. Patient-reported visual analog scale ratings of pain intensity were conducted upon initial clinical presentation and at 4, 8, 12, 24, 48, and 72 h after completion of pulpectomy. Results showed that at the 4- and 8-h periods, both rofecoxib and ibuprofen provided significantly better pain relief than placebo. At the 12- and 24-h periods, rofecoxib demonstrated significantly better pain relief than both ibuprofen and placebo. Patients with a periapical diagnosis of acute apical periodontitis showed a significantly increased need for additional medication after completion of pulpectomy compared with all other periapical diagnoses.