Isotopes illustrate vertical transport of anthropogenic Pb by reversible scavenging within Pacific Ocean particle veils.

Reversible scavenging, the oceanographic process by which dissolved metals exchange onto and off sinking particles and are thereby transported to deeper depths, has been well established for the metal thorium for decades. Reversible scavenging both deepens the elemental distribution of adsorptive elements and shortens their oceanic residence times in the ocean compared to nonadsorptive metals, and scavenging ultimately removes elements from the ocean via sedimentation. Thus, it is important to understand which metals undergo reversible scavenging and under what conditions. Recently, reversible scavenging has been invoked in global biogeochemical models of a range of metals including lead, iron, copper, and zinc to fit modeled data to observations of oceanic dissolved metal distributions. Nonetheless, the effects of reversible scavenging remain difficult to visualize in ocean sections of dissolved metals and to distinguish from other processes such as biological regeneration. Here, we show that particle-rich "veils" descending from high-productivity zones in the equatorial and North Pacific provide idealized illustrations of reversible scavenging of dissolved lead (Pb). A meridional section of dissolved Pb isotope ratios across the central Pacific shows that where particle concentrations are sufficiently high, such as within particle veils, vertical transport of anthropogenic surface-dissolved Pb isotope ratios toward the deep ocean is manifested as columnar isotope anomalies. Modeling of this effect shows that reversible scavenging within particle-rich waters allows anthropogenic Pb isotope ratios from the surface to penetrate ancient deep waters on timescales sufficiently rapid to overcome horizontal mixing of deep water Pb isotope ratios along abyssal isopycnals.

Boundary exchange completes the marine Pb cycle jigsaw.

Material fluxes at the land-ocean interface impact seawater composition and global cycling of elements. However, most attention has been focused on the fluvial dissolved fluxes. For elements like lead (Pb), whose fluvial particulate flux into the ocean is two orders of magnitude higher than the dissolved counterpart, the role of particulates in elemental cycling is potentially important but currently less appreciated. Using both chemical analyses on samples collected from around equatorial Southeast Asia and model simulations, we show that particulate-dissolved exchange is an important mechanism controlling the concentration and isotopic composition of dissolved Pb in the ocean. Our model indicates that Pb contributed from particulate-dissolved exchange at ocean boundaries is larger than, or at least comparable to, other major Pb sources to the seawater before the Anthropocene, when the anthropogenic Pb was absent. Our work highlights the importance of boundary exchange in understanding marine element cycling and weathering-climate feedback.

Trivalent chromium isotopes in the eastern tropical North Pacific oxygen-deficient zone.

Changes in chromium (Cr) isotope ratios due to fractionation between trivalent [Cr(III)] and hexavalent [Cr(VI)] are being utilized by geologists to infer oxygen conditions in past environments. However, there is little information available on Cr in the modern ocean to ground-truth these inferences. Transformations between the two chromium species are important processes in oceanic Cr cycling. Here we present profiles of hexavalent and trivalent Cr concentrations and stable isotope ratios from the eastern tropical North Pacific (ETNP) oxygen-deficient zone (ODZ) which support theoretical and experimental studies that predict that lighter Cr is preferentially reduced in low-oxygen environments and that residual dissolved Cr becomes heavier due to removal of particle-reactive Cr(III) on sinking particles. The Cr(III) maximum dominantly occurs in the upper portion of the ODZ, implying that microbial activity (dependent on the sinking flux of organic matter) may be the dominant mechanism for this transformation, rather than a simple inorganic chemical conversion between the species depending on the redox potential.

Expert Consensus of Data Elements for Collection for Enhanced Recovery After Cardiac Surgery.

BACKGROUND: Despite the emergence of Enhanced Recovery Protocols (ERPs) in cardiac surgery, there is no consensus on the essential elements for data reporting for quality improvement efforts, as well as accountability and standardization of outcome reporting across institutions. The aim of this study was to establish a consensus on essential data elements for cardiac ERAS®. METHODS: A 2-round modified Delphi technique was utilized based on existing recommendations from the recently published ERAS® cardiac surgery consensus guidelines. Round 1 included a steering committee of 10 experts who oversaw formulation of a focused list of data elements into 3 main areas: Preoperative, intraoperative and postoperative. Round 2 consisted of a multidisciplinary, multinational, heterogenous group of 50 voting experts from across the United States and Europe. All participants evaluated their level of agreement with each data element using a 5-point Likert scale with consensus threshold of 70%. RESULTS: In round 1, 17 data elements were considered essential (consensus > = 70%, either positive or negative) and 6 were considered marginal (consensus < = 70%, either positive or negative). In round 2, positive consensus was achieved for 15/17 (88.2%) data elements in the essential category, and all six data elements (100%) in the marginal category, indicating a high level of overall agreement. CONCLUSION: This initial study, which identified 21 key data elements for collection in an ERAS® cardiac program, will aid clinicians in establishing a framework for evaluating the quality of their contemporary ERP processes and will allow acquisition of data to help benchmark performance metrics between hospitals.

Distal transport of dissolved hydrothermal iron in the deep South Pacific Ocean.

Until recently, hydrothermal vents were not considered to be an important source to the marine dissolved Fe (dFe) inventory because hydrothermal Fe was believed to precipitate quantitatively near the vent site. Based on recent abyssal dFe enrichments near hydrothermal vents, however, the leaky vent hypothesis [Toner BM, et al. (2012) Oceanography 25(1):209-212] argues that some hydrothermal Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (<0.4 µm) measurements from the abyssal southeast and southwest Pacific Ocean, where dFe of 1.0-1.5 nmol/kg near 2,000 m depth (0.4-0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be hydrothermally derived based on its correlation with primordial (3)He and dissolved Mn (dFe:(3)He of 0.9-2.7 × 10(6)). Given the known sites of hydrothermal venting in these regions, this dFe must have been transported thousands of kilometers away from its vent site to reach our sampling stations. Additionally, changes in the size partitioning of the hydrothermal dFe between soluble (<0.02 µm) and colloidal (0.02-0.4 µm) phases with increasing distance from the vents indicate that dFe transformations continue to occur far from the vent source. This study confirms that although the southern East Pacific Rise only leaks 0.02-1% of total Fe vented into the abyssal Pacific, this dFe persists thousands of kilometers away from the vent source with sufficient magnitude that hydrothermal vents can have far-field effects on global dFe distributions and inventories (≥3% of global aerosol dFe input).

Recent distribution of lead in the Indian Ocean reflects the impact of regional emissions.

Humans have injected lead (Pb) massively into the earth surface environment in a temporally and spatially evolving pattern. A significant fraction is transported by the atmosphere into the surface ocean where we can observe its transport by ocean currents and sinking particles. This study of the Indian Ocean documents high Pb concentrations in the northern and tropical surface waters and extremely low Pb levels in the deep water. North of 20°S, dissolved Pb concentrations decrease from 42 to 82 pmol/kg in surface waters to 1.5-3.3 pmol/kg in deep waters. South of 20°S, surface water Pb concentrations decrease from 21 pmol/kg at 31°S to 7 pmol/kg at 62°S. This surface Pb concentration gradient reflects a southward decrease in anthropogenic Pb emissions. The upper waters of the north and central Indian Ocean have high Pb concentrations resulting from recent regional rapid industrialization and a late phase-out of leaded gasoline, and these concentrations are now higher than currently seen in the central North Pacific and North Atlantic oceans. The Antarctic sector of the Indian Ocean shows very low concentrations due to limited regional anthropogenic Pb emissions, high scavenging rates, and rapid vertical mixing, but Pb still occurs at higher levels than would have existed centuries ago. Penetration of Pb into the northern and central Indian Ocean thermocline waters is minimized by limited ventilation. Pb concentrations in the deep Indian Ocean are comparable to the other oceans at the same latitude, and deep waters of the central Indian Ocean match the lowest observed oceanic Pb concentrations.

Methanogenic burst in the end-Permian carbon cycle.

The end-Permian extinction is associated with a mysterious disruption to Earth's carbon cycle. Here we identify causal mechanisms via three observations. First, we show that geochemical signals indicate superexponential growth of the marine inorganic carbon reservoir, coincident with the extinction and consistent with the expansion of a new microbial metabolic pathway. Second, we show that the efficient acetoclastic pathway in Methanosarcina emerged at a time statistically indistinguishable from the extinction. Finally, we show that nickel concentrations in South China sediments increased sharply at the extinction, probably as a consequence of massive Siberian volcanism, enabling a methanogenic expansion by removal of nickel limitation. Collectively, these results are consistent with the instigation of Earth's greatest mass extinction by a specific microbial innovation.

Lead isotope exchange between dissolved and fluvial particulate matter: a laboratory study from the Johor River estuary.

Atmospheric aerosols are the dominant source of Pb to the modern marine environment, and as a result, in most regions of the ocean the Pb isotopic composition of dissolved Pb in the surface ocean (and in corals) matches that of the regional aerosols. In the Singapore Strait, however, there is a large offset between seawater dissolved and coral Pb isotopes and that of the regional aerosols. We propose that this difference results from isotope exchange between dissolved Pb supplied by anthropogenic aerosol deposition and adsorbed natural crustal Pb on weathered particles delivered to the ocean by coastal rivers. To investigate this issue, Pb isotope exchange was assessed through a closed-system exchange experiment using estuarine waters collected at the Johor River mouth (which discharges to the Singapore Strait). During the experiment, a known amount of dissolved Pb with the isotopic composition of NBS-981 (206Pb/207Pb = 1.093) was spiked into the unfiltered Johor water (dissolved and particulate 206Pb/207Pb = 1.199) and the changing isotopic composition of the dissolved Pb was monitored. The mixing ratio of the estuarine and spike Pb should have produced a dissolved 206Pb/207Pb isotopic composition of 1.161, but within a week, the 206Pb/207Pb in the water increased to 1.190 and continued to increase to 1.197 during the next two months without significant changes of the dissolved Pb concentration. The kinetics of isotope exchange was assessed using a simple Kd model, which assumes multiple sub-reservoirs within the particulate matter with different exchange rate constants. The Kd model reproduced 56% of the observed Pb isotope variance. Both the closed-system experiment and field measurements imply that isotope exchange can be an important mechanism for controlling Pb and Pb isotopes in coastal waters. A similar process may occur for other trace elements.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

The anterior saphenous vein. Part 1. A position statement endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: There is a lack of clarity regarding the terminology of the anterior accessory saphenous vein (AASV) that can impact treatment outcomes. Although use of the word "accessory" implies that the vein is a superficial tributary, evidence supports its role as a truncal vein, similar to the great and small saphenous veins, and warranting a change in terminology. METHODS: A multisocietal panel was convened by the American Vein and Lymphatic Society (AVLS), the Union International of Phlebology (UIP), and the American Venous Forum (AVF). The group was charged with reviewing the existing anatomic and clinical literature pertaining to the term "anterior accessory saphenous vein" and to consider the need for alternative terminology. CONCLUSIONS: Based on the insights gathered from the literature review and extensive discussions, the panel recommends changing the terminology such that the "anterior accessory saphenous vein" (AASV) now be designated the anterior saphenous vein (ASV).

The anterior saphenous vein. Part 4. Clinical and technical considerations in treatment. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: The decision to treat a refluxing anterior saphenous vein (ASV) should be a clinical decision based on the assessment on the ASV's contribution to patient's signs and symptoms. Once the decision to treat has been made, there are anatomic, clinical, and technical considerations in treatment planning. METHODS: Clinical scenarios were discussed by a panel of experts and common anatomic, clinical, and technical considerations were identified. RESULTS: There are unique clinical considerations such as whether both the great saphenous vein (GSV) and ASV should be concomitantly treated, if a normal ASV should be treated when treating a refluxing GSV and when and how to treat the associated tributary varicose tributaries. Being aware of the anatomic, clinical, and technical considerations allows development of a treatment plan that optimizes long-term outcomes in patients with ASV reflux. CONCLUSION: Ultimately the treatment plan should be tailored to address these types of variables in a patient-centered discussion.

The Anterior Saphenous Vein. Part 2. Anatomic considerations in normal and refluxing patients. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum and the International Union of Phlebology.

BACKGROUND: The term Anterior Accessory of the Great Saphenous Vein suggest this is a branch tributary vein despite this vessel's anatomic features of a truncal vein. A multisocietal group suggested to designate this the Anterior Saphenous Vein (ASV). This study was aimed to evaluate its ultrasound anatomy in normal and varicose limbs. METHODS: The clinical anatomy of the ASV was evaluated by narrative review of the literature. Additionally, the course of the ASV was evaluated in 62 limbs with no evidence of venous disease and 62 limbs with varicosities. RESULTS: The ASV length, patterns of origin and termination are reported in both normal and patients with varicose veins. Discussion of the patterns is supported by the narrative review of the literature. CONCLUSIONS: The ASV must be considered a truncal vein and its treatment modalities should be the same that for the great and small saphenous veins rather than a tributary vein.

The anterior saphenous vein. Part 3. Systematic review of the literature and payor coverage policies. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum and the International Union of Phlebology.

OBJECTIVE: The objective of this study is to systemically review the literature on Anterior Saphenous Vein (ASV) reflux treatment and insurance impediments to treatment coverage. METHODS: A literature search was performed using a PRISMA framework. In addition, a cross-sectional analysis of insurance policies for ASV treatment was evaluated. RESULTS: Published evidence and treatment considerations in the literature for ASV treatment are discussed. In 155 of 226 (68.6%) insurance policies reviewed coverage of ASV ablation was allowed while 62/226 (27.4%) did not specify coverage and 9/226 (4.0%) specified ASV treatment was not covered. Of the 155 that provide ASV coverage, 98 (62.2%) provide coverage with criteria such as requiring prior treatment of the great saphenous vein. CONCLUSIONS: Vein treatment experts should continue to advocate to insurance carriers to update their varicose vein treatment policies to reflect the substantial clinical evidence so that patients with ASV reflux can be appropriately treated.

The anterior saphenous vein. Part 4. Clinical and technical considerations in treatment. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: The decision to treat a refluxing anterior saphenous vein (ASV) should be a clinical decision based on the assessment on the ASV's contribution to patient's signs and symptoms. Once the decision to treat has been made, there are anatomic, clinical, and technical considerations in treatment planning. METHODS: Clinical scenarios were discussed by a panel of experts and common anatomic, clinical, and technical considerations were identified. RESULTS: There are unique clinical considerations such as whether both the great saphenous vein (GSV) and ASV should be concomitantly treated, if a normal ASV should be treated when treating a refluxing GSV and when and how to treat the associated tributary varicose tributaries. Being aware of the anatomic, clinical, and technical considerations allows development of a treatment plan that optimizes long-term outcomes in patients with ASV reflux. CONCLUSIONS: Ultimately the treatment plan should be tailored to address these types of variables in a patient-centered discussion.

The anterior saphenous vein. Part 2. Anatomic considerations in normal and refluxing patients. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: The term Anterior Accessory of the Great Saphenous Vein suggests this is a branch tributary vein despite this vessel's anatomic features of a truncal vein. A multisocietal group suggested to designate this the anterior saphenous vein (ASV). This study was aimed to evaluate its ultrasound anatomy in normal and varicose limbs. METHODS: The clinical anatomy of the ASV was evaluated by narrative review of the literature. Additionally, the course of the ASV was evaluated in 62 limbs with no evidence of venous disease and 62 limbs with varicosities. RESULTS: The ASV length, patterns of origin and termination are reported in both normal and patients with varicose veins. Discussion of the patterns is supported by the narrative review of the literature. CONCLUSIONS: The ASV must be considered a truncal vein and its treatment modalities should be the same that for the great and small saphenous veins rather than a tributary vein.

The anterior saphenous vein. Part 3. Systematic review of the literature and payor coverage policies. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

OBJECTIVE: The objective of this study is to systemically review the literature on Anterior Saphenous Vein (ASV) reflux treatment and insurance impediments to treatment coverage. METHODS: A literature search was performed using a PRISMA framework. In addition, a cross-sectional analysis of insurance policies for ASV treatment was evaluated. RESULTS: Published evidence and treatment considerations in the literature for ASV treatment are discussed. In 155 of 226 (68.6%) insurance policies reviewed coverage of ASV ablation was allowed while 62/226 (27.4%) did not specify coverage and 9/226 (4.0%) specified ASV treatment was not covered. Of the 155 that provide ASV coverage, 98 (62.2%) provide coverage with criteria such as requiring prior treatment of the great saphenous vein. CONCLUSIONS: Vein treatment experts should continue to advocate to insurance carriers to update their varicose vein treatment policies to reflect the substantial clinical evidence so that patients with ASV reflux can be appropriately treated.

The anterior saphenous vein. Part 1. A position statement endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: There is a lack of clarity regarding the terminology of the anterior accessory saphenous vein (AASV) that can impact treatment outcomes. Although use of the word "accessory" implies that the vein is a superficial tributary, evidence supports its role as a truncal vein, similar to the great and small saphenous veins, and warranting a change in terminology. METHODS: A multisocietal panel was convened by the American Vein and Lymphatic Society (AVLS), the Union International of Phlebology (UIP), and the American Venous Forum (AVF). The group was charged with reviewing the existing anatomic and clinical literature pertaining to the term "anterior accessory saphenous vein" and to consider the need for alternative terminology. CONCLUSION: Based on the insights gathered from the literature review and extensive discussions, the panel recommends changing the terminology such that the "anterior accessory saphenous vein" (AASV) now be designated the anterior saphenous vein (ASV).

Novel Image-Guided Percutaneous Lung Tissue Excision Device With Integrated Sealing of Blood Vessels and Airways: An In Vivo Preclinical Study.

OBJECTIVE: This study evaluated the efficacy of the Minimally Invasive Targeted Resection (MiTR) device, a novel electrosurgical instrument that allows for targeted excision of a lung abnormality while using bipolar radiofrequency (RF) energy to seal blood vessels and airways. METHODS: The MiTR system was evaluated in 7 acute and 2 chronic porcine (7-day) models to evaluate the efficacy of tissue excision with bipolar RF sealing of blood vessels and airways and application of an autologous blood patch into the excised tissue cavity. Air leak was recorded for all evaluations. The study was approved by the institutional ethical board. RESULTS: Nineteen lung tissue samples, measuring 2.5 cm long × 1.2 cm diameter, were excised. In 8 of 9 animals (89%), hemostasis and pneumostasis were observed visually at the completion of the procedure. In 2 of 2 chronic animals (100%), hemostasis and pneumostasis persisted for the 7-day observation period. Histologic examination of the excised samples showed preservation of the core parenchymal architecture without evident tissue damage of the samples that would impair pathologic analysis. CONCLUSIONS: Percutaneous resection of targeted lung tissue with the MiTR system demonstrated hemostasis and pneumostasis while obtaining a histologically intact sample. After regulatory approval, the use of this device could offer more tissue for analysis than a transthoracic needle biopsy or bronchoscopy and a far less invasive alternative to video-assisted thoracic surgery or thoracotomy. This may also expand patient and physician options for the early diagnosis and treatment of lung cancer.

Detection of iron ligands in seawater and marine cyanobacteria cultures by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry.

Organic ligands dominate the speciation of iron in the ocean. Little is known, however, about the chemical composition and distribution of these compounds. Here, we describe a method to detect low concentrations of organic Fe ligands using reverse-phase high-performance liquid chromatography (HPLC) tandem multicollector inductively coupled plasma mass spectrometry. This technique can be used to screen seawater and marine cultures for target compounds that can be isolated and structurally characterized. Sensitive detection (<1 picomole Fe) is achieved using an iron-free HPLC system to reduce background Fe levels, minimizing (40)Ar(16)O(+) interferences on (56)Fe with a hexapole collision cell, and introducing oxygen into the sample carrier gas to prevent the formation of reduced carbon deposits that decrease sensitivity. This method was tested with a chromatographic separation of five trace metal complexes that represent the polarity range likely found in seawater. Good separation was achieved with a 20 min water/methanol gradient, although sensitivity decreased by a factor of 2 at high organic solvent concentrations. Finally, Fe ligand complexes were detected from the organic extract of surface South Pacific seawater and from culture media of the siderophore producing cyanobacteria Synechococcus sp. PCC 7002.

The epidemiology of endodontic complexity in general dental practice: a prevalence study.

Aim To determine the prevalence and the epidemiology of the factors influencing endodontic complexities in general dental practice.Method Eligible cases where endodontic treatment was indicated as a treatment option were collected by a total of 30 general dental practitioners based in the UK. Online-based Endodontic Complexity Assessment Tool (E-CAT) was used to determine the perceived complexity of each case. In total, 22 categories, including patient- and tooth-related factors, were recorded.Results Collectively, 435 non-surgical root canal treatment cases were assessed. Overall, 72% of the root canal treatments encountered in general dental practice were found to be either uncomplicated (Class I) or moderately complicated (Class II) and can be considered within the remit of general dental practitioners. Despite the relatively equal distribution of the assessed teeth, the proportion of extraction as a proposed treatment for posterior teeth was more than double that of anterior teeth.Conclusion The results obtained in this study provide a good resource and databank for researchers, educators, public health commissioners and academic institutions to access a wide range of information concerning the prevalence and distribution of endodontic complexity.