Characterization of PFAS air emissions from thermal application of fluoropolymer dispersions on fabrics.

During thermal processes utilized in affixing fluoropolymer coatings dispersion to fibers and fabrics, coating components are vaporized. It is suspected that per- and polyfluoroalkyl substances (PFAS) from the dispersions may undergo chemical transformations at the temperatures used, leading to additional emitted PFAS thermal byproducts. It is important to characterize these emissions to support evaluation of the resulting environmental and health impacts. In this study, a bench-scale system was built to simulate this industrial process via thermal application of dispersions to fiberglass utilizing relevant temperatures and residence times in sequential drying, baking, and sintering steps. Experiments were performed with two commercially available dispersions and a simple model mixture containing a single PFAS (6:2 fluorotelomer alcohol [6:2 FTOH]). Vapor-phase emissions were sampled and characterized by several off-line and real-time mass spectrometry techniques for targeted and nontargeted PFAS. Results indicate that multiple PFAS thermal transformation products and multiple nonhalogenated organic species were emitted from the exit of the high temperature third (sintering) furnace when 6:2 FTOH was the only PFAS present in the aqueous mixture. This finding supports the hypothesis that temperatures typical of these industrial furnaces may also induce chemical transformations within the fluorinated air emissions. Experiments using the two commercial fluoropolymer dispersions indicate air emissions of part-per-million by volume (ppmv) concentrations of heptafluoropropyl-1,2,2,2-tetrafluoroethyl ether (Fluoroether E1), as well as other PFAS at operationally relevant temperatures. We suspect that E1 is a direct thermal decomposition product (via decarboxylation) of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid (commonly referred to as HFPO-DA) present in the dispersions. Other thermal decomposition products, including the monomer, tetrafluoroethene, may originate from the PFAS used to stabilize the dispersion or from the polymer particles in suspension. This study represents the first researcher-built coating application simulator to report nontargeted PFAS emission characterization, real-time analyses, and the quantification of 30 volatile target PFAS.Implications: Thermal processes used to affix fluoropolymers to fabrics are believed to be a source of PFAS air emissions. These coating operations are used by many large and small manufacturers and typically do not currently require any air emissions control. This research designed and constructed a bench-scale system that simulates these processes and used several off-line and advanced real-time mass spectroscopy techniques to characterize PFAS air emissions from two commercial fluoropolymer dispersions. Further, as the compositions of commercial dispersions are largely unknown, a model three-component solution containing a single PFAS was used to characterize emissions of multiple PFAS thermal transformation products at operationally relevant conditions. This research shows that fluoropolymer fabric coating facilities can be sources of complex mixtures of PFAS air emissions that include volatile and semivolatile PFAS present in the dispersions, as well as PFAS byproducts formed by the thermal transformation of fluorocarbon and hydrocarbon species present in these dispersions.

Pilot-Scale Thermal Destruction of Per- and Polyfluoroalkyl Substances in a Legacy Aqueous Film Forming Foam.

The destruction of per- and polyfluoroalkyl substances (PFAS) is critical to ensure effective remediation of PFAS contaminated matrices. The destruction of hazardous chemicals within incinerators and other thermal treatment processes has historically been determined by calculating the destruction efficiency (DE) or the destruction and removal efficiency (DRE). While high DEs, >99.99%, are deemed acceptable for most hazardous compounds, many PFAS can be converted to other PFAS at low temperatures resulting in high DEs without full mineralization and the potential release of the remaining fluorocarbon portions to the environment. Many of these products of incomplete combustion (PICs) are greenhouse gases, most have unknown toxicity, and some can react to create new perfluorocarboxylic acids. Experiments using aqueous film forming foam (AFFF) and a pilot-scale research combustor varied the combustion environment to determine if DEs indicate PFAS mineralization. Several operating conditions above 1090 °C resulted in high DEs and few detectable fluorinated PIC emissions. However, several conditions below 1000 °C produced DEs >99.99% for the quantifiable PFAS and mg/m3 emission concentrations of several non-polar PFAS PICs. These results suggest that DE alone may not be the best indication of total PFAS destruction, and additional PIC characterization may be warranted.

Boron isotopes in boninites document rapid changes in slab inputs during subduction initiation.

How subduction-related magmatism starts at convergent plate margins is still poorly understood. Here we show that boron isotope variations in early-formed boninites from the Izu-Bonin arc, combined with radiogenic isotopes and elemental ratios document rapid (~0.5 to 1 Myr) changes in the sources and makeup of slab inputs as subduction begins. Heterogeneous hornblende-granulite facies melts from ocean crust gabbros ± basalts fluxed early melting to generate low silica boninites. Hydrous fluids from slab sediments and basalts later fluxed the low silica boninites mantle source to produce high silica boninites. Our results suggest that initially the uppermost parts of the slab were accreted near the nascent trench, perhaps related to early low-angle subduction. The rapid changes in slab inputs recorded in the boninites entail a steepening subduction angle and cooling of the plate interface, allowing for subduction of slab sediment and basalt, and generating hydrous fluids at lower slab temperatures.

Combustion of C1 and C2 PFAS: Kinetic modeling and experiments.

A combustion model, originally developed to simulate the destruction of chemical warfare agents, was modified to include C1-C3 fluorinated organic reactions and kinetics compiled by the National Institute of Standards and Technology (NIST). A simplified plug flow reactor version of this model was used to predict the destruction efficiency (DE) and formation of products of incomplete combustion (PICs) for three C1 and C2 per- and poly-fluorinated alkyl substances (PFAS) (CF4, CHF3, and C2F6) and compare predicted values to Fourier Transform Infrared spectroscopy (FTIR)-based measurements made from a pilot-scale EPA research combustor (40-64 kW, natural gas-fired, 20% excess air). PFAS were introduced through the flame, and at post-flame locations along a time-temperature profile allowing for simulation of direct flame and non-flame injection, and examination of the sensitivity of PFAS destruction on temperature and free radical flame chemistry. Results indicate that CF4 is particularly difficult to destroy with DEs ranging from ~60 to 95% when introduced through the flame at increasing furnace loads. Due to the presence of lower energy C-H and C-C bonds to initiate molecular dissociation reactions, CHF3 and C2F6 were easier to destroy, exhibiting DEs >99% even when introduced post-flame. However, these lower bond energies may also lead to the formation of CF2 and CF3 radicals at thermal conditions unable to fully de-fluorinate these species and formation of fluorinated PICs. DEs determined by the model agreed well with the measurements for CHF3 and C2F6 but overpredicted DEs at high temperatures and underpredicted DEs at low temperatures for CF4. However, high DEs do not necessarily mean absence of PICs, with both model predictions and limited FTIR measurements indicating the presence of similar fluorinated PICs in the combustion emissions. The FTIR was able to provide real-time emission measurements and additional model development may improve prediction of PFAS destruction and PIC formation.Implications: The widespread use of PFAS for over 70 years has led to their presence in multiple environmental matrixes including human tissues. While the chemical and thermal stability of PFAS are related to their desirable properties, this stability means that PFAS are very slow to degrade naturally and potentially difficult to destroy completely through thermal treatment processes often used for organic waste destruction. In this applied combustion study, model PFAS compounds were introduced to a pilot-scale EPA research furnace. Real-time FTIR measurements were performed of the injected compound and trace products of incomplete combustion (PICs) at operationally relevant conditions, and the results were successfully compared to kinetic model predictions of those same PFAS destruction efficiencies and trace gas-phase PIC constituents. This study represents a significant potential enhancement in available tools to support effective management of PFAS-containing wastes.

Molybdenum isotopes unmask slab dehydration and melting beneath the Mariana arc.

How serpentinites in the forearc mantle and subducted lithosphere become involved in enriching the subarc mantle source of arc magmas is controversial. Here we report molybdenum isotopes for primitive submarine lavas and serpentinites from active volcanoes and serpentinite mud volcanoes in the Mariana arc. These data, in combination with radiogenic isotopes and elemental ratios, allow development of a model whereby shallow, partially serpentinized and subducted forearc mantle transfers fluid and melt from the subducted slab into the subarc mantle. These entrained forearc mantle fragments are further metasomatized by slab fluids/melts derived from the dehydration of serpentinites in the subducted lithospheric slab. Multistage breakdown of serpentinites in the subduction channel ultimately releases fluids/melts that trigger Mariana volcanic front volcanism. Serpentinites dragged down from the forearc mantle are likely exhausted at >200 km depth, after which slab-derived serpentinites are responsible for generating slab melts.

Low Temperature Thermal Treatment of Gas-Phase Fluorotelomer Alcohols by Calcium Oxide.

Given the extent to which per- and polyfluoroalkyl substances (PFAS) are used in commercial and industrial applications, the need to evaluate treatment options that reduce environmental emissions and human and ecological exposures of PFAS is becoming more necessary. One specific chemical class of PFAS, fluorotelomer alcohols (FTOHs), have vapor pressures such that a significant fraction is expected to be present in the gas-phase even at ambient temperatures. FTOHs are used in a variety of PFAS applications, including synthesis and material coatings. Using two complementary mass spectrometric methods, the use of calcium oxide (CaO) was examined as a low temperature and potentially low-cost thermal treatment media for removal and destruction of four gas-phase FTOHs of varying molecular weights. This was accomplished by assessing the removal/destruction efficiency of the FTOHs and the formation of fluorinated byproducts as a function of treatment temperature (200 - 800 °C) in the presence of CaO compared to thermal-only destruction. During the treatment process, there is evidence that other PFAS compounds are produced at low temperatures (200 - 600 °C) as the primary FTOH partially degrades. At temperatures above 600 °C, thermal treatment with CaO prevented the formation or removed nearly all these secondary products.

Characterization of emissions from a pilot-scale combustor operating on coal blended with woody biomass.

Emissions generated from the combustion of coal have been a subject of regulation by the United States Environmental Protection Agency (U.S. EPA) and State agencies for years, as they have been associated with adverse effects on human health and the environment. Over the past several decades, regulations on these facility emissions have become more stringent and have therefore caused industry to look toward new pre- and post-combustion control technologies. In more recent years, there has been a "push" toward renewable and cleaner burning alternative fuels as replacements for traditional fossil fuels. Part of this "push" has been accomplished by States and Regions offering incentives and options for renewable portfolios, which over half of the states now have in some form. The current study investigates the potential changes in both gaseous and particulate emissions from the use of a variety of woody biomass materials as a drop-in replacement for coal as compared to use of 100% bituminous coal. Four different biomass materials are blended individually with coal at 20% and 40% by mass for testing on the U.S. EPA's Multi-Pollutant Control Research Facility, a pilot-scale coal-fired facility located in Research Triangle Park, North Carolina. Emissions are calculated based on measurements from the flue gas to characterize gaseous species (CO, CO2, NOX, SO2, other acid gases, and several organic hazardous air pollutants) as well as fine and ultrafine particulate (mass, size distribution, number count, elemental carbon, organic carbon, and black carbon) and compared among each combination of fuels and 100% bituminous coal.

Mariana serpentinite mud volcanism exhumes subducted seamount materials: implications for the origin of life.

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean Drilling Program and International Ocean Discovery Program cores of serpentinite mudflows that confirm exhumation of various Pacific Plate lithologies, including subducted reef limestone; (4) petrologic, geochemical and paleontological data from the cores that show that Pacific Plate seamount exhumation covers greater spatial and temporal extents; (5) the inference that microbial communities associated with serpentinite mud volcanism may also be exhumed from the subducted plate seafloor and/or seamounts; and (6) the implications for effects of these processes with regard to evolution of life. This article is part of a discussion meeting issue 'Serpentine in the Earth system'.

The evolution of healthcare disaster preparedness and response training at the FEMA Center for Domestic Preparedness.

The Center for Domestic Preparedness (CDP) in partnership with the US Department of Health and Human Services Assistant Secretary for Preparedness and Response is using a multiagency/organization, targeted, collaborative approach to adjust existing courses and develop responsive new courses to provide best practices education and experiential learning techniques in healthcare facility emergency resilience, preparedness, response, and recovery applicable to all first receivers. The CDP in Anniston, AL, is a Federal Emergency Management Agency training facility for the Nation's state, local, tribal, and territorial first responders and healthcare professionals. The Center's role has rapidly evolved to provide healthcare emergency preparedness, response, and management training. Through the integration of its Noble Training Facility, a former military hospital, the training courses replicate disaster and mass casualty emergency situations. Patient simulators enable triage and assessment of treatment for mass casualty surge skills application while an isolation ward serves as a training laboratory for the care of patients with infectious diseases of specific concern. Ambulance simulators and an eight-bay treatment area add authenticity to an integrated capstone event accompanying select classes.

Chinese Physicians' Perspectives on the 2017 American College of Cardiology/American Heart Association Hypertension Guideline: A Mobile App-Based Survey.

INTRODUCTION: Hypertension is a leading global risk factor for death and disability. Seeking new ways to prevent and treat hypertension is a priority for scientists and healthcare professionals worldwide. In November 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA) issued a new hypertension guideline shifting the definition of hypertension from 140/90 mm Hg to 130/80 mm Hg for systolic/diastolic blood pressure. This new diagnostic threshold of hypertension has sparked a lively discussion worldwide over whether it should be applied in clinical settings to diagnose and treat hypertension. China, the world's most populous country, is facing a hypertension crisis. According to the 140/90 mm Hg guideline, China has an estimated 244.5 million population aged ≥ 18 years with hypertension, and another 435.3 million with pre-hypertension. If the new guideline is adopted, the prevalence of hypertension in China would double. This change would significantly impact patients, healthcare professionals, scientists, and policy makers in terms of the delivery of care and needed resources. AIM: This study aims to investigate whether Chinese physicians will use the 130/80 mm Hg threshold to diagnose hypertension in clinical practice. METHODS: In March 2018, we launched a mobile app-based survey to study 253 Chinese physicians' perspectives on the ACC/AHA Guideline. RESULTS: A total of 253 physicians from 21 Chinese provinces completed the survey. Nearly 80% of the participants had already noticed the ACC/AHA guideline change. The proportion of participants who said they would use the new threshold to diagnoses hypertension was 41%, while 59% said they would not use the new threshold. The primary reason for those who said "yes" was that they believed early diagnosis of hypertension can trigger early actions to prevent the increasing blood pressure. For those who said "no", they argued that their decision was based on the fact that the Chinese Hypertension Prevention Guideline had not yet changed the diagnostic threshold from 140/90 to 130/80 mm Hg. CONCLUSIONS: Different understanding of hypertension prevention and treatment exists among Chinese physicians. It is an emergent need to form an evidence-based authoritative answer to guide Chinese physicians' future clinical practice.

The evolution of response and management training at the FEMA Center for Domestic Preparedness.

The Federal Emergency Management Agency (FEMA) Center for Domestic Preparedness (CDP) was established in 1998 and is now 20 years old. In its short history, the CDP has significantly evolved the relevance and responsiveness of its courses and its capability to provide high-fidelity, hands-on training, and exercises to meet the demanding needs of today's responders. This article discusses the basis of need for a competent, responder training program; the genesis of the CDP as a no-cost provider of responder training for state, local, tribal, and territorial responders; describes the current training opportunities available to responders; previews emerging training opportunities that are under development or envisioned in the very near future; and provides insight to the future progression of the CDP as it continues to expand and evolve its role as FEMA's premiere, responder focused, hands-on training provider.

Magmatic Response to Subduction Initiation: Part 1. Fore-arc Basalts of the Izu-Bonin Arc From IODP Expedition 352.

The Izu-Bonin-Mariana (IBM) fore arc preserves igneous rock assemblages that formed during subduction initiation circa 52 Ma. International Ocean Discovery Program (IODP) Expedition 352 cored four sites in the fore arc near the Ogasawara Plateau in order to document the magmatic response to subduction initiation and the physical, petrologic, and chemical stratigraphy of a nascent subduction zone. Two of these sites (U1440 and U1441) are underlain by fore-arc basalt (FAB). FABs have mid-ocean ridge basalt (MORB)-like compositions, however, FAB are consistently lower in the high-field strength elements (TiO2, P2O5, Zr) and Ni compared to MORB, with Na2O at the low end of the MORB field and FeO* at the high end. Almost all FABs are light rare earth element depleted, with low total REE, and have low ratios of highly incompatible to less incompatible elements (Ti/V, Zr/Y, Ce/Yb, and Zr/Sm) relative to MORB. Chemostratigraphic trends in Hole U1440B are consistent with the uppermost lavas forming off axis, whereas the lower lavas formed beneath a spreading center axis. Axial magma of U1440B becomes more fractionated upsection; overlying off-axis magmas return to more primitive compositions. Melt models require a two-stage process, with early garnet field melts extracted prior to later spinel field melts, with up to 23% melting to form the most depleted compositions. Mantle equilibration temperatures are higher than normal MORB (1,400 °C-1,480 °C) at relatively low pressures (1-2 GPa), which may reflect an influence of the Manus plume during subduction initiation. Our data support previous models of FAB origin by decompression melting but imply a source more depleted than normal MORB source mantle.

An mHealth intervention to improve medication adherence among patients with coronary heart disease in China: Development of an intervention.

OBJECTIVES: With this study, we aimed to develop a mobile technology (mHealth) intervention to improve medication adherence among patients with coronary heart disease (CHD). METHODS: The study was conducted in two phases with CHD patients from a Cardiology Department of a hospital located in China. Each phase was independent from the other. Phase 1 tested the integration of the two apps - "WeChat" and "BB Reminder" - as an mHealth intervention. All participants received the same educational materials via WeChat every two days. Participants in the experimental group received a reminder from BB Reminder for every dose of their medications. The duration of Phase 1 was 30 days for each participant. Phase 2 refined the intervention, in which educational materials were sent every five days rather than every two days, and medication-taking reminders were sent daily rather than every dose. RESULTS: In Phase 1, an mHealth intervention was developed by integrating two mobile apps. In Phase 2, medication adherence increased at 30-day follow-up in both groups compared to baseline. At the 30-day follow-up, the mean of the decrease in medication non-adherence score in the experimental group (M = -1.35, SD = 2.18, n = 36) was more than the decrease in control group (M = -0.69, SD = 1.58, n = 36), which means the medication adherence improved more in the experimental group. CONCLUSION: The feasibility of using mHealth to remind CHD patients to take their medications is high.

Comparison of gaseous and particulate emissions from a pilot-scale combustor using three varieties of coal.

Gaseous and particulate emissions generated from the combustion of coal have been associated with adverse effects on human health and the environment, and have therefore been the subject of regulation by federal and state government agencies. Detailed emission characterizations are needed to better understand the impacts of pre- and post-combustion controls on a variety of coals found in the United States (U.S.). While the U.S. Environmental Protection Agency (EPA) requires industry reporting of emissions for criteria and several hazardous air pollutants (HAPs), many of the methods for monitoring and measuring these gaseous and particulate emissions rely on time-integrated sampling techniques. Though these emissions reports provide an overall representation of day-to-day operations, they represent well-controlled operations and do not encompass real combustion events that occur sporadically. The current study not only characterizes emissions from three coals (bituminous, sub-bituminous, and lignite), but also investigates the use of instrumentation for improved measurement and monitoring techniques that provide real-time, continuous emissions data. Testing was completed using the U.S. EPA's Multi-Pollutant Control Research Facility, a pilot-scale coal-fired combustor using industry-standard emission control technologies, in Research Triangle Park, North Carolina. Emissions were calculated based on measurements from the flue gas (pre- and post-electrostatic precipitator), to characterize gaseous species (CO, CO2, O2, NOX, SO2, other acid gases, and several organic HAPs) as well as fine and ultrafine particulate (mass, size distribution, number count, elemental carbon, organic carbon, and black carbon). Comparisons of traditional EPA methods to those made via Fourier Transfer Infrared (FTIR) Spectroscopy for CO, NOX, and SO2 are also reported.

Association between physician time-unlimited vs time-limited internal medicine board certification and ambulatory patient care quality.

IMPORTANCE: American Board of Internal Medicine (ABIM) initiatives encourage internists with time-unlimited certificates to recertify. However, there are limited data evaluating differences in performance between internists with time-limited or time-unlimited board certification. OBJECTIVE: To determine whether there are differences in primary care quality between physicians holding time-limited or time-unlimited certification. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of performance data from 1 year (2012-2013) at 4 Veterans Affairs (VA) medical centers. Participants were internists with time-limited (n = 71) or time-unlimited (n = 34) ABIM certification providing primary care to 68,213 patients. Median physician panel size was 610 patients (range, 19-1316), with no differences between groups (P = .90). MAIN OUTCOMES AND MEASURES: Ten primary care performance measures: colorectal screening rates; diabetes with glycated hemoglobin (HbA1c level) less than 9.0%; diabetes with blood pressure less than 140/90 mm Hg; diabetes with low-density lipoprotein cholesterol (LDL-C) level less than 100 mg/dL; hypertension with blood pressure less than 140/90 mm Hg; thiazide diuretics used in multidrug hypertensive regimen; atherosclerotic coronary artery disease and LDL-C level less than 100 mg/dL; post-myocardial infarction use of aspirin; post-myocardial infarction use of ß-blockers; congestive heart failure (CHF) with use of angiotensin-converting enzyme (ACE) inhibitor. RESULTS: After adjustment for practice site, panel size, years since certification, and clustering by physician, there were no differences in outcomes for patients cared for by internists with time-limited or time-unlimited certification for any performance measure: colorectal screening (odds ratio [OR], 0.95 [95% CI, 0.89-1.01]); diabetes with HbA1c level less than 9.0% (OR, 0.96 [95% CI, 0.74-1.2]); blood pressure control (OR, 0.99 [95% CI, 0.69-1.4]); LDL-C level less than 100 mg/dL (OR, 1.1 [95% CI, 0.79-1.5]); hypertension with blood pressure less than 140/90 mm Hg (OR, 1.0 [95% CI, 0.92-1.2]); thiazide use (OR, 1.0 [95% CI, 0.8-1.3]); atherosclerotic coronary artery disease with LDL-C level less than 100 mg/dL (OR, 1.1 [95% CI, 0.75-1.7]); post-myocardial infarction use of aspirin (OR, 0.98 [95% CI, 0.58-1.68]) or ß-blockers (OR, 1.0 [95% CI, 0.57-1.9]); CHF with use of ACE inhibitor (OR, 0.98 [95% CI, 0.61-1.6]). CONCLUSIONS AND RELEVANCE: Among internists providing primary care at 4 VA medical centers, there were no significant differences between those with time-limited ABIM certification and those with time-unlimited ABIM certification on 10 primary care performance measures. Additional research to examine the difference in patient outcomes among holders of time-limited and time-unlimited certificates in non-VA and nonacademic settings and the association with other ABIM goals may help clarify the potential benefit of Maintenance of Certification participation.

Behavior of mercury emissions from a commercial coal-fired power plant: the relationship between stack speciation and near-field plume measurements.

The reduction of divalent gaseous mercury (Hg(II)) to elemental gaseous mercury (Hg(0)) in a commercial coal-fired power plant (CFPP) exhaust plume was investigated by simultaneous measurement in-stack and in-plume as part of a collaborative study among the U.S. EPA, EPRI, EERC, and Southern Company. In-stack continuous emission monitoring data were used to establish the CFPP's real-time mercury speciation and plume dilution tracer species (SO2, NOX) emission rates, and an airship was utilized as an airborne sampling platform to maintain static position with respect to the exhaust plume centerline for semicontinuous measurement of target species. Varying levels of Hg(II) concentration (2.39-3.90 µg m(-3)) and percent abundance (∼ 87-99%) in flue gas and in-plume reduction were observed. The existence and magnitude of Hg(II) reduction to Hg(0) (0-55%) observed varied with respect to the types and relative amounts of coals combusted, suggesting that exhaust plume reduction occurring downwind of the CFPP is influenced by coal chemical composition and characteristics.

A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel.

An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor's normalized electrical resistance (R/R0) decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor's normalized capacitance (C/C0) increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite.

Mandibular first molar with six separate canals.

INTRODUCTION: Many anatomical variations can occur within the mandibular first molar. Commonly, 3-4 canals are located, but as many as 6-7 canals have been reported. METHODS: This report describes a case of a mandibular first molar with 6 separate canals (3 mesial and 3 distal) that was instrumented with conventional hand and rotary files and obturated by using a hybrid warm vertical compaction technique. RESULTS: Recall examination as far as 3 years post-treatment found no sensitivity to percussion or palpation and recall radiographs after treatment show resolution of the previous apical periodontitis. CONCLUSIONS: The existence of such teeth as these underlies the importance of looking for additional canals.

Possible role of hypercoagulability in calciphylaxis: review of the literature.

BACKGROUND: The role of a hypercoagulable state in the pathogenesis of calciphylaxis has yet to be determined. OBJECTIVE: We sought to find evidence of an association between hypercoagulability and calciphylaxis. METHODS: We reviewed the primary literature for review articles, studies, and case reports that discussed or demonstrated a possible relationship between calciphylaxis and a hypercoagulable state. RESULTS: Review of the primary literature showed that in cases of calciphylaxis with reported levels of protein C and S, 38% of the patients had decreased protein C levels and 43% had decreased levels of protein S. From review of case reports, 3 cases of improvement of skin lesions with low molecular weight heparin treatment, and a fourth case of healing of skin lesions with tissue plasminogen activator treatment, were found. Calciphylaxis was also found in a patient with antiphospholipid antibody syndrome, and a patient with cryofibrinogenemia had clinical and histologic findings consistent with possible calciphylaxis. LIMITATIONS: A limited number of reports were available for review. CONCLUSION: Our review of the literature found sufficient evidence to suggest a possible role of a hypercoagulable state in the pathogenesis of calciphylaxis. A prospective study with serial testing of all relevant clotting factors in patients with calciphylaxis is needed to more definitively establish this role.

Gender differences in analgesia for endodontic pain.

The purpose of this prospective clinical trial was to investigate the analgesic efficacy of three oral medication groups on postoperative endodontic pain in male and female dental patients, with an emphasis on analgesic differences between the sexes. Forty-three patients were administered ibuprofen 600 mg, placebo, or pentazocine 50 mg/0.5 mg naloxone in a randomized, double-blinded manner. Beginning immediately after endodontic treatment, patients took the assigned medication every 6 hours for 24 hours and recorded their degree of discomfort on a 100-mm visual analog scale. Statistical analysis of the data showed that ibuprofen 600 mg provided statistically significantly greater analgesia than placebo at 6 and 12 hours (P = 0.0014 and 0.0024), and pentazocine/naloxone provided statistically significantly greater analgesia than placebo at 12 hours (P = 0.0084). Sex-dependent differences were noted within the pentazocine/naloxone group, which showed significantly greater analgesia in females compared with males (P = 0.007).