Publications by authors named "Harth C"

Acute gastric variceal bleeding is a rare but serious complication of portal hypertension. Initial therapy for bleeding gastric varices focuses on acute hemostasis. In this regard, endoscopic cyanoacrylate injection (ECI) is the first-line approach.

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HFC-23 (trifluoromethane) is a potent greenhouse gas released to the atmosphere primarily as a by-product of HCFC-22 (chlorodifluoromethane) synthesis. Since 2020, the Kigali Amendment to the Montreal Protocol has required Parties to destroy their HFC-23 emissions to the extent possible. Here, we present updated HFC-23 emissions estimated from atmospheric observations.

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The perfluorocarbons tetrafluoromethane (CF, PFC-14) and hexafluoroethane (CF, PFC-116) are potent greenhouse gases with near-permanent atmospheric lifetimes relative to human timescales and global warming potentials thousands of times that of CO. Using long-term atmospheric observations from a Chinese network and an inverse modeling approach (top-down method), we determined that CF emissions in China increased from 4.7 (4.

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Global concentrations (or mole fractions) and emissions of ozone-depleting substances (ODSs) and their hydrofluorocarbon (HFCs) substitutes that are controlled by the Montreal Protocol and its Amendments and adjustments (MP) are of great interest to both the scientific community and public. Previous studies on global concentrations and emissions have mostly relied on ground-based observations. Here, we assess the global concentrations and emissions of eight MP controlled substances and methyl chloride from ACE-FTS (Atmospheric Chemistry Experiment high-resolution infrared Fourier transform spectrometer) satellite observations: CFC-11 (CFCl), CFC-12 (CFCl), CCl, HCFC-22 (CHClF), HCFC-141b (CHClF), HCFC-142b (CHClF), HFC-23 (CHF), HFC-134a (CHF), and CHCl.

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Global emissions of the ozone-depleting gas HCFC-141b (1,1-dichloro-1-fluoroethane, CHCClF) derived from measurements of atmospheric mole fractions increased between 2017 and 2021 despite a fall in reported production and consumption of HCFC-141b for dispersive uses. HCFC-141b is a controlled substance under the Montreal Protocol, and its phase-out is currently underway, after a peak in reported consumption and production in developing (Article 5) countries in 2013. If reported production and consumption are correct, our study suggests that the 2017-2021 rise is due to an increase in emissions from the bank when appliances containing HCFC-141b reach the end of their life, or from production of HCFC-141b not reported for dispersive uses.

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The perfluorocarbons (PFCs), tetrafluoromethane (CF) and hexafluoroethane (CF), are potent greenhouse gases with very long atmospheric lifetimes. They are emitted almost entirely from industrial sources, including the aluminum and rare earth metal smelting industries that emit them as by-products, and the semiconductor and flat panel display manufacturing industries that use them and vent unutilized amounts to the atmosphere. Despite extensive industrial efforts to quantify and curb these emissions, "top-down" PFC emission estimates derived from atmospheric measurements continue to rise and are significantly greater than reported process- and inventory-based "bottom-up" emissions.

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Objective: According to the angiosome concept ulcer healing and limb salvage should be superior if direct arterial flow to the source vessel of an affected angiosome is established compared to indirect flow where the angiosome is perfused by means of collaterals. The objective of this study was to evaluate the impact of direct versus indirect revascularization (DR/IR) in endovascular versus bypass surgery on ulcer healing, limb salvage and mortality.

Materials And Methods: A retrospective analysis of both endovascular and bypass distal (below the knee) lower limb revascularizations for chronic limb-threatening ischemia (CLTI) between 1993 and 2014 was performed.

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  • Emissions of ozone-depleting CFC-11 decreased since the mid-1980s due to the Montreal Protocol, but an unexpected rise started in 2013, mainly from eastern China.
  • *Researchers used atmospheric observations and models to uncover that CFC-11 emissions in this region returned to pre-2013 levels by 2019, following a notable decrease after a peak.
  • *Additionally, elevated emissions of related compounds suggested ongoing CFC-11 production in eastern China post-2013, but timely actions by industry and government may have prevented significant delay in ozone layer recovery.
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  • The atmospheric levels of CFC-11, a harmful ozone-depleting substance, have been decreasing since the Montreal Protocol, but there was a worrying slowdown in this decline due to unexpected emissions starting in 2013.
  • Recent data shows a significant drop in global CFC-11 emissions from 2018 to 2019, indicating a reduction in unreported production.
  • If this trend of decreasing emissions continues, it could limit future ozone depletion despite a growing reserve of un-emitted CFC-11.
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Global and regional atmospheric measurements and modeling can play key roles in discovering and quantifying unexpected nascent emissions of environmentally important substances. We focus here on three hydrochlorofluorocarbons (HCFCs) that are restricted by the Montreal Protocol because of their roles in stratospheric ozone depletion. Based on measurements of archived air samples and on in situ measurements at stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, we report global abundances, trends, and regional enhancements for HCFC-132b ([Formula: see text]), which is newly discovered in the atmosphere, and updated results for HCFC-133a ([Formula: see text]) and HCFC-31 ([Formula: see text]ClF).

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Objective: In the presence of long lesions, in patients with chronic limb threatening ischaemia, a femorodistal bypass is often the only option to avoid major amputation. This study investigated whether targeted bypass to the affected angiosome, according to the angiosome concept definition of direct (DR) and indirect revascularisation (IR), has an impact on wound healing, major amputation rate, and mortality.

Methods: A retrospective analysis was performed at Ghent University Hospital of 201 non-healing ischaemic wounds (Rutherford categories 5 and 6) requiring femorodistal bypass surgery in 177 patients (61% male, median age 69 years) with a follow up of 36 months.

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Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (ΔC, δC, and δD) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response to deglacial warming were small (<19 teragrams of methane per year, 95% confidence interval) and argue against similar methane emissions in response to future warming.

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Atmospheric methane (CH) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era. Fossil fuel extraction and use are among the largest anthropogenic sources of CH emissions, but the precise magnitude of these contributions is a subject of debate. Carbon-14 in CH (CH) can be used to distinguish between fossil (C-free) CH emissions and contemporaneous biogenic sources; however, poorly constrained direct CH emissions from nuclear reactors have complicated this approach since the middle of the 20th century.

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Under the Kigali Amendment to the Montreal Protocol, new controls are being implemented to reduce emissions of HFC-23 (CHF[Formula: see text]), a by-product during the manufacture of HCFC-22 (CHClF[Formula: see text]). Starting in 2015, China and India, who dominate global HCFC-22 production (75% in 2017), set out ambitious programs to reduce HFC-23 emissions. Here, we estimate that these measures should have seen global emissions drop by 87% between 2014 and 2017.

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Article Synopsis
  • The decline in atmospheric concentrations of ozone-depleting gases, particularly CFC-11, is crucial for the recovery of the stratospheric ozone layer, but there has been a worrying slowdown in this decline since 2012.
  • A recent investigation indicates that emissions of CFC-11 from eastern mainland China have significantly increased, primarily from the Shandong and Hebei provinces, accounting for 40 to 60 percent of the global rise in emissions.
  • This increase raises concerns about potential new production and use of CFC-11, which contradicts the Montreal Protocol's commitment to phase out such substances by 2010.
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  • A 55-year-old patient with intraventricular pneumocephalus was admitted due to balance issues, tinnitus, and ear fullness, linked to a bony defect from otomastoiditis.
  • *CT scans revealed pneumocephalus from chronic otomastoiditis, while nasal fluid analysis confirmed a leak with beta-transferrin.
  • *Post-surgery, most symptoms improved, but the patient continued to experience mild-to-moderate headaches; CT scans are crucial for diagnosing pneumocephalus and identifying its cause, with MRI providing additional clarity on fistula locations.
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Carbon tetrachloride (CCl) is an ozone-depleting substance, accounting for about 10% of the chlorine in the troposphere. Under the terms of the Montreal Protocol, its production for dispersive uses was banned from 2010. In this work we show that, despite the controls on production being introduced, CCl emissions from the eastern part of China did not decline between 2009 and 2016.

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Methane (CH) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane (CH) in the past atmosphere and show that geological methane emissions were no higher than 15.

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The growth in global methane (CH) concentration, which had been ongoing since the industrial revolution, stalled around the year 2000 before resuming globally in 2007. We evaluate the role of the hydroxyl radical (OH), the major CH sink, in the recent CH growth. We also examine the influence of systematic uncertainties in OH concentrations on CH emissions inferred from atmospheric observations.

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A 66-year-old Caucasian female presented with insidious sciatic pain leading to an uncommon diagnosis of tuberculous osteomyelitis with unknown portal entry. The patient did not report a history of a previous tuberculosis (TB) infection and her chest X-ray was negative for TB. Considering TB in the differential diagnosis of a 'bone abscess', it is of paramount importance to come to a correct diagnosis.

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The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance.

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We have developed a chemical mechanism describing the tropospheric degradation of chlorine containing very short-lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( ClyVSLS) between 2005 and 2013. By constraining the model with surface measurements of chloroform (CHCl), dichloromethane (CHCl), tetrachloroethene (CCl), trichloroethene (CHCl), and 1,2-dichloroethane (CHClCHCl), we infer a 2013 ClyVSLS mixing ratio of 123 parts per trillion (ppt).

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