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The last 30 years have been a period of intense and continuous international negotiations to deal with climate change. During the same 30 years, humanity has doubled the amount of anthropogenic carbon dioxide in the atmosphere. There has, however, been progress and some notable successes in the negotiations. In 2015, at the 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC), 196 countries adopted the Paris Agreement stating that they would limit global temperatures to well below 2°C above pre-industrial levels and would pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels. The first review of the Paris agreement was at COP26 in Glasgow with many countries pledging to go net zero emissions by the middle of the century. But currently these pledges, if fulfilled, will only limit global average temperature to 2.4˚C to 2.8˚C. At COP27 in Egypt the core agreements from the Glasgow Climate Pact were maintained and countries finally agreed to set up a Loss and Damage facility – though details of who finances and who can claim are still be to be worked out. This article reviews the key moments in the history of international climate change negotiations and discusses what the key objectives are for future COP meetings.

In the five years since the Paris Agreement, achieving net zero emissions has become a defining frame for climate action. We review over 4000 countries, companies, and subnational governments, which together make up the preponderance of global emissions. We find 769 of these entities have net zero targets, but only 152 meet minimum criteria for robustness, including timing, status, coverage, use of offsets, and governance. Though net zero is now widespread as a concept, its operationalization is still in its infancy. Making net zero targets robust should now be a priority for policymakers in order to deliver Paris-consistent action, as well as securing more ambitious targets. Key policy insightsNet zero targets now cover two-thirds of the global economy, but robust net zero targets only cover around five percent.Strengthening targets and their implementation is particularly needed in the following areas: target status (including setting targets into law); coveraneuge of activities; limits to and transparency regarding the use of offsets; and publication of plans and of progress reports.Policymakers should aim to strengthen net zero targets by setting standards for robust net zero targets; building the capacity of entities, particularly those in the global South, to meet the technical and resource challenges required to effectively operationalize net zero emission targets. Net zero targets now cover two-thirds of the global economy, but robust net zero targets only cover around five percent. Strengthening targets and their implementation is particularly needed in the following areas: target status (including setting targets into law); coveraneuge of activities; limits to and transparency regarding the use of offsets; and publication of plans and of progress reports. Policymakers should aim to strengthen net zero targets by setting standards for robust net zero targets; building the capacity of entities, particularly those in the global South, to meet the technical and resource challenges required to effectively operationalize net zero emission targets.

Climate justice needs to be at the heart of the COP27 negotiations in Sharm El Sheikh. Climate justice is not just a financial transaction to protect the environment. It needs to be seen as the protection of the most vulnerable in society after centuries of resource exploitation. African countries disproportionately face impacts of climate change on their environments, their economies, their resources, and their infrastructure. This leads to greater vulnerability and increased exposure to the negative effects of a changing climate. In this article, we highlight the importance of climate justice and its role within the UN negotiations, and ultimately in concrete action. We discuss current climate impacts across key sectors in the African region, with a focus on health, infrastructure, food and water scarcity, energy, and finance. All sectors are affected by climate change. They are interconnected and under threat. This triggers a ripple effect, where threats in one sector have a knock-on effect on other sectors. We find that the current set of intergovernmental institutions have failed to adequately address climate justice. We also contend that a siloed approach to climate action has proven to be ineffective. As we head towards the next set of negotiations (COP27), this paper argues that the economic and social conditions in Africa can be addressed through financial and collaborative support for adaptation and localised solutions, but that this will only be achieved if climate justice is prioritised by the decision makers. This needs to include a global-scale transition in how climate finance is assessed and accessed. Climate justice underpins real effective and sustainable solutions for climate action in Africa.

The last 30 years have been a period of intense and continuous international negotiation to deal with climate change. During the same 30 years, humanity has doubled the amount of anthropogenic carbon dioxide in the atmosphere. There has, however, been progress and some notable successes. In 2015 at COP21, 196 countries signed the Paris Agreement stating that they would limit global temperatures to well below 2°C above pre-industrial levels and would pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels. This was followed up at COP26 in Glasgow with many countries pledging to go net zero emissions by the middle of the century. But currently these pledges, if fulfilled, will only limit global average temperature to 2.4˚C to 2.8˚C. This article reviews the history of international climate change negotiations and examines what the key objectives are for future COP meetings.

Respiratory syncytial virus (RSV) remains a leading cause of medically-attended acute respiratory infection in infants and children. With multiple preventative interventions under development, accurate estimates of health care resource utilization are essential for policy decision making.We developed a literature-based decision-tree model that estimated annual medically-attended RSV (MA-RSV) lower respiratory tract infection (LRTI) and non-LRTI episodes in the US for all infants and for high-risk toddlers. The model accounted for the gestational age and birth-month of infants, and the seasonal variation in RSV incidence. The impact of no prophylaxis, palivizumab, maternal vaccine, and long-acting monoclonal antibody (mAb) interventions was estimated.We estimated 1.23 million (range: 0.96 million-1.40 million) annual MA-RSV LRTI/non-LRTI episodes comprised of 1.19 million (range: 0.93 million-1.36 million) emergency department (ED) and outpatient visits, and 39,040 (range: 32,726-45,851) hospitalizations. Outpatient and ED visits were comprised of 586,034 (range: 430,595-718,868) LRTIs and 608,733 (range: 495,705-644,658) non-LRTIs. The long-acting mAb intervention resulted in the greatest number of averted outpatient and ED episodes (310,997 [53%] LRTIs; 284,305 [47%] non-LRTIs) and hospitalizations (21,845 [56%]). Full-term infants constitute the highest proportion of episodes across all interventions.MA-RSV disease is substantial in infants and high-risk toddlers. Long-acting mAbs are most effective at reducing the number of MA-RSV LRTI/non-LRTI episodes, and the only intervention that prevents disease in older infants (≥6 months old).

This study aimed to improve local management of paediatric otitis media using the 2022 American-Academy of Otolaryngology Head and Neck Surgery (AAO-HNS) Clinical Practice Guideline for Tympanostomy Tubes in Children.A SQUIRE 2.0 compliant quality improvement study was carried out within the outpatient department of our otolaryngology tertiary referral centre. Local outpatient management of paediatric otitis media was compared to the AAO-HNS guidelines, specifically focussing on the decision to offer tympanostomy tubes. Following initial audit of practice, an educational session was performed within the otolaryngology department and local practice was subsequently re-evaluated.Overall, 88 children were included (46 pre-intervention and 42 post-intervention) with a mean age of 7.6 years (range 1-12 years). Sixty-four (72.7%) children presented with suspected otitis media with effusion. The remainder presented with recurrent or persistent acute otitis media (24/88, 27.3%). Twenty-six children were offered tympanostomy tubes (29.5%). Initial evaluation of practice identified that the decision to offer tympanostomy tubes was guideline appropriate in 76.1% of children (35/46). This significantly improved following an educational session (40/42, 95.2%, p = 0.02). The reasons for non-guideline compliance included: otitis media with effusion3 months, no evidence of middle ear fluid and patients meeting criteria for tympanostomy tube insertion not being offered.A focussed educational intervention may improve local adherence to guidelines in the management of paediatric otitis media. Continued re-evaluation of local practice is essential in order to ensure children are managed in accordance with the guidelines.

Laryngeal malignancy encompasses about 1% of all cancers. Chondrosarcoma in the head and neck region represents about 0.1% of head and neck malignancies. Typical presenting symptoms relate to the anatomical location of these tumours and include dysphonia, inspiratory stridor, dysphagia, odynophagia or a neck mass. Benign and malignant cartilaginous cancers of the larynx have been described, and preoperative diagnosis can be difficult. Our report highlights the surgical management of a male patient in his 50s with chondrosarcoma of the thyroid cartilage.

Multiple analytical and preclinical studies were performed to compare the biochemical characteristics, pharmacokinetics (PK), safety and neoantigenicity of a new 5% liquid formulation of Alpha-1 Proteinase Inhibitor (Liquid A1PI, Prolastin®-C Liquid) with the lyophilized version (Lyophilized A1PI, Prolastin®-C). Liquid A1PI and Lyophilized A1PI had similar average mass (~52 kDa), and both forms exhibited glycoform patterns consistent with the known banding pattern of A1PI (dominated by the M6 and M4 bands, including deconvoluted masses). Both Liquid A1PI and Lyophilized A1PI yielded average percent purity values ranging from 96% to 99% and had active content ranging from 53 mg/mL to 59 mg/mL. The PK profile of Liquid A1PI was similar to Lyophilized A1PI. Safety assessments in rabbits showed good tolerability and no test article-related changes in mortality, clinical signs, clinical pathology, body weight, food consumption, or urinalysis parameters. Following immunodepletion of antibodies that recognize Lyophilized A1PI, there were no significant differences in the anti-drug titers among animals immunized with Lyophilized A1PI and Liquid A1PI (p > 0.05), indicating that no antibodies to neoantigens were generated. Liquid A1PI and Lyophilized A1PI have similar profiles with respect to biochemical characteristics, PK, safety and neoantigenicity.

Introduction Corona-virus Disease 2019 (COVID-19) has had a huge impact on the delivery of healthcare worldwide, particularly elective surgery. There is a lack of data regarding risk of postoperative COVID-19 infection in children undergoing elective surgery, and regarding the utility of pre-operative COVID-19 testing, and preoperative “cocooning” or restriction of movements. The purpose of this present study was to examine the safety of elective paediatric Otolaryngology surgery during the COVID-19 pandemic with respect to incidence of postoperative symptomatic COVID-19 infection or major respiratory complications. Materials and methods Prospective cohort study of paediatric patients undergoing elective Otolaryngology surgery between September and December 2020. Primary outcome measure was incidence of symptomatic COVID-19 or major respiratory complications within the 14 days after surgery. Parents of prospectively enrolled patients were contacted 14 days after surgery and enquiry made regarding development of postoperative symptoms, COVID-19 testing, or diagnosis of COVID-19. Results 302 patients were recruited. 125 (41.4%) underwent preoperative COVID-19 RTPCR testing. 66 (21.8%) restricted movements prior to surgery. The peak 14-day COVID-19 incidence during the study was 302.9 cases per 100,000 population. No COVID-19 infections or major respiratory complications were reported in the 14 day follow up period. Conclusion The results of our study support the safety of elective paediatric Otolaryngology surgery during the pandemic, in the setting of community incidence not exceeding that observed during the study period., Graphical abstract Image 1

Laryngocoele is a rare entity, defined as an abnormal cystic dilatation of saccule of the laryngeal ventricle. Three types of laryngocele have been described, based on their relation to the thyrohyoid membrane: internal, external or mixed type. Symptoms are variable, including neck swelling, shortness of breath, dysphonia and fever, if the laryngocoele becomes infected. Patients may also present in extremis with airway obstruction. We present the case of a healthy 34-year-old gentleman with acute airway obstruction due to a mixed infected laryngocoele. Flexible nasoendoscopy showed a large cystic swelling arising from the laryngeal ventricle. Computed tomography of neck confirmed a right paraglottic collection extending into the ventricle and glottis, causing significant airway compromise. The patient was managed with microlaryngoscopy and cystic decompression. At outpatient follow up, he was completely asymptomatic and is currently under surveillance. Endoscopic decompression is a safe and effective initial management for mixed laryngocoele.

What explains legislators’ behavior when they are uncertain whether they will be rewarded or punished at re-election? Typically, politicians are incentivized to deliver policies preferred by the ma...

Immune globulin subcutaneous, human 20% solution (IGSC-C 20%, Xembify®)—a new 20% immunoglobulin (IgG) liquid product for subcutaneous (SC) administration—has been developed by Grifols. The IGSC-C 20% formulation is based on knowledge acquired from the formulation of Immune Globulin Injection (Human),10% Caprylate/Chromatography Purified (IGIV-C 10%, Gamunex®-C). The protein concentration was increased from 10% to 20% to provide a smaller volume for SC administration. The IGSC-C 20% manufacturing process employs the same caprylate/chromatography purification steps as IGIV-C 10%, with the addition of an ultrafiltration step so that the product can be formulated at a higher protein concentration. IGSC-C 20% has been produced at full industrial scale to support clinical studies and licensure. These batches were characterized using a comprehensive panel of analytical testing. The new IGSC-C 20% product maintains the same composition, neutralizing activity, purity, and quality characteristics found in IGIV-C 10%.

Multiple analytical and preclinical studies were performed to compare the biochemical characteristics, pharmacokinetics (PK), safety and neoantigenicity of a new 5% liquid formulation of Alpha-1 Proteinase Inhibitor (Liquid A1PI, Prolastin®-C Liquid) with the lyophilized version (Lyophilized A1PI, Prolastin®-C). Liquid A1PI and Lyophilized A1PI had similar average mass (~52 kDa), and both forms exhibited glycoform patterns consistent with the known banding pattern of A1PI (dominated by the M6 and M4 bands, including deconvoluted masses). Both Liquid A1PI and Lyophilized A1PI yielded average percent purity values ranging from 96% to 99% and had active content ranging from 53 mg/mL to 59 mg/mL. The PK profile of Liquid A1PI was similar to Lyophilized A1PI. Safety assessments in rabbits showed good tolerability and no test article-related changes in mortality, clinical signs, clinical pathology, body weight, food consumption, or urinalysis parameters. Following immunodepletion of antibodies that recognize Lyophilized A1PI, there were no significant differences in the anti-drug titers among animals immunized with Lyophilized A1PI and Liquid A1PI (p 0.05), indicating that no antibodies to neoantigens were generated. Liquid A1PI and Lyophilized A1PI have similar profiles with respect to biochemical characteristics, PK, safety and neoantigenicity.

Subglottic Eosinophilic Angiocentric Fibrosis (EAF) is an extremely rare disease of an elusive aetiology. It is chronically progressive benign condition that causes narrowing of the subglottic region leading to dysphonia and airway compromise. The diagnosis is historical and imaging is nonspecific. We report a case xc of 56-year-old lady referred to our institution with globus sensation, hoarseness, and mild stridor. Incidental subglottic mass was found at time of diagnostic microlaryngoscopy and biopsy confirmed subglottic EAF. All laboratory investigations were unremarkable. Lesion was removed with laryngeal microdebrider and three courses of intravenous dexamethasone were administered. Patient’s postoperative period was uneventful and had remained disease free for 1 year. To date, no consensus has been reached on the optimal treatment of subglottic EAF. We recommend regular follow-up to detect early recurrence.

Reflecting on current trends impacting higher education today, it is undeniable that pressure exists on institutions of higher education to fulfill the demands and expectations of students to acquire global competencies through curricular and co-curricular global experiences (Hovland 2009). According to the Center for Internationalization and Global Engagement (Center for Internationalization and Global Engagement 2012), one of the fundamental duties of US higher education is to prepare students “to live and work in a society that increasingly operates across international borders” (p. 5).

In this study, the effects of carbon starvation history on the induction kinetics of aerobic toluene degradation by Ralstonia pickettii PKO1 were quantitatively explored. Experimental results suggested that (i) the durations of the lag and transient phases depended upon both the duration of prior carbon starvation ( T stv ) and the inducer concentration, and (ii) that post-transient-phase (PTP) induction levels were independent of T stv but dependent upon inducer concentration. The observed relationships among toluene degradation, carbon starvation history, and inducer concentration were incorporated into a modified Michaelis–Menten equation in order to refine the traditional model of enzymatic biodegradation. The refined model was able to predict toluene breakthrough in a porous medium in which previously carbon-starved cells were reactivated with a continuous supply of toluene. These findings suggested a means of improving the accuracy of existing models of biodegradation in groundwater under conditions of fluctuating substrate/inducer concentration.

This study examines the volatilization behavior of binary nonaqueous phase liquid (NAPL) mixtures consisting of styrene, and toluene or tetrachloroethylene (PCE). Residual NAPL saturations were emplaced in unsaturated (residual water saturation) soil columns packed with Wagner 50-80 sand. Initial column effluent concentrations were measured for the NAPL mixtures at several pore gas phase velocities. Rate-limited volatilization occurred at higher gas phase pore velocities, and mass transfer coefficients could be reasonably predicted with a correlation developed from single component NAPL volatilization data. Long-term volatilization studies for the binary NAPL mixtures were also conducted. The effluent concentrations for both NAPL components were observed to be initially proportional to their mole fractions. After the more volatile component became depleted, a rapid drop in the effluent concentration of this component was accompanied by an increase in the mole fraction and effluent concentration of the remaining constituent to near saturated values until the free phase NAPL was volatilized. The final stage of removal was associated with a dramatic decrease in effluent concentration, attributed to reduction in the gas-NAPL interfacial area, followed by low concentration tailing. The tailing and subsequent flow interruption behavior are likely a consequence of rate-limited desorption. Equilibrium and rate-limited simulations of the long-term volatilization experiments did not provide a satisfactory description of the data. A simulation that included a fixed concentration gradient and fitted activity coefficients provided a better characterization of the volatilization data. Various potential explanations for this “fixed gradient” volatilization behavior were considered, but additional research is needed to test these hypotheses.

The efficiency and effectiveness of soil vapor extraction (SVE) and bioventing (BV) systems for remediation of unsaturated zone soils is controlled by a complex combination of physical, chemical and biological factors. The Michigan soil vapor extraction remediation (MISER) model, a two-dimensional numerical simulator, is developed to advance our ability to investigate the performance of field scale SVE and BV systems by integrating processes of multiphase flow, multicomponent compositional transport with nonequilibrium interphase mass transfer, and aerobic biodegradation. Subsequent to the model presentation, example simulations of single well SVE and BV systems are used to illustrate the interplay between physical, chemical and biological processes and their potential influence on remediation efficiency and the pathways of contaminant removal. Simulations of SVE reveal that removal efficiency is controlled primarily by the ability to engineer gas flow through regions of organic liquid contaminated soil and by interphase mass transfer limitations. Biodegradation is found to play a minor role in mass removal for the examined SVE scenarios. Simulations of BV systems suggest that the effective supply of oxygen may not be the sole criterion for efficient BV performance. The efficiency and contaminant removal pathways in these systems can be significantly influenced by interdependent dynamics involving biological growth factors, interphase mass transfer rates, and air injection rates. Simulation results emphasize the need for the continued refinement and validation of predictive interphase mass transfer models applicable under a variety of conditions and for the continued elucidation and quantification of microbial processes under unsaturated field conditions.

A 77-year-old man, 7 years after left pneumonectomy, was scheduled for a right upper pulmonary lobectomy. The early identification of a newly developing carcinoma on the right upper pulmonary lobe warranted surgical resection. Right exploratory thoracotomy, pleural lysis, partial pleurectomy, and right upper lobe wedge resection were completed, and the patient was discharged without sequelae. This case report describes the intraoperative anesthetic management of a right upper lobe wedge resection and attributes the uneventful intraoperative outcome to a strategically and skillfully placed left double-lumen endotracheal tube.

Thrombate III® is a highly purified antithrombin concentrate that has been used by clinicians worldwide for more than two decades for the treatment of hereditary antithrombin deficiency. The manufacturing process is based on heparin-affinity chromatography and pasteurization. To modernize the process and to further enhance the pathogen safety profile of the final product, despite the absence of infectious disease transmission, a nanofiltration step was added. The biochemical characterization and pathogen safety evaluation of Thrombate III® manufactured using the modernized process are presented. Bioanalytical data demonstrate that the incorporation of nanofiltration has no impact on the antithrombin content, potency, and purity of the product. Scaledown models of the manufacturing process were used to assess virus and prion clearance under manufacturing setpoint conditions. Additionally, robustness of virus clearance was evaluated at or slightly outside the manufacturing operating limits. The results demonstrate that pasteurization inactivated both enveloped and non-enveloped viruses. The addition of nanofiltration substantially increased clearance capacities for both enveloped and non-enveloped viruses by approximately 4–6 log10. In addition, the process achieves 6.0 log10 ID50 prion infectivity clearance. Thus, the introduction of nanofiltration increased the pathogen safety margin of the manufacturing process without impacting the key biochemical characteristics of the product.

The cytotoxic T lymphocyte (CTL) response to the infection of CD4+ T cells by human T cell leukemia virus type I (HTLV-I) has previously been modelled using standard response functions, with relatively simple dynamical outcomes. In this paper, we investigate the consequences of a more general CTL response and show that a sigmoidal response function gives rise to complex behaviours previously unobserved. Multiple equilibria are shown to exist and none of the equilibria is a global attractor during the chronic infection phase. Coexistence of local attractors with their own basin of attractions is the norm. In addition, both stable and unstable periodic oscillations can be created through Hopf bifurcations. We show that transient periodic oscillations occur when a saddle-type periodic solution exists. As a consequence, transient periodic oscillations can be robust and observable. Implications of our findings to the dynamics of CTL response to HTLV-I infections in vivo and pathogenesis of HAM/TSP are discussed.

Inadvertent deflation of the endotracheal tube cuff during a tracheotomy can complicate the surgical procedure, especially in a morbidly obese patient. Also, the anesthesia provider may lose control of the airway, with the inability to reintubate in case of airway edema, airway secretions, or airway fire. The use of the GlideScope video laryngoscope (Verathon Inc, Bothell, Washington) in the morbidly obese patient undergoing a tracheotomy has clinical benefits. This device allowed the visualization of the airway anatomy in 2 patients and the manipulation of the punctured endotracheal tube cuff in one case.

SUMMARY The advantages associated with the use of self-adaptive methods for the solution of problems which require the prediction of a frontal position in time are well known. In this paper a self-adaptive finite element solution for the non-linear unsaturated flow equation is developed using hierarchic p-version enrichment of the interpolating space. Additional computational advantages are demonstrated for an iteration scheme in which iterations after enrichment are performed only over a subdomain. Numerical solutions are presented for a one-dimensional infiltration scenario. INTRODUCTION AND BACKGROUND Many problems of environmental significance require the prediction of the displacement of a front with time. When solving such problems numerically, methods which provide greater resolution at the front where the state variable is changing most rapidly are computationally desirable. These models are commonly described as 'self-adaptive' in the literature. By enriching the approximation, based on feedback from previous solutions, self-adaptive methods can produce improved solutions, both in terms of efficiency and reliability.' In this paper a self-adaptive finite element method is presented for the numerical solution of the non-linear Fokker-Planck equation for the transient isothermal flow of water into a non-swelling unsaturated soil2 The solution is obtained in one-dimension, with initial and boundary condi- tions and functional forms for the non-linear terms after Haverkamp et aL3 In the presented application the saturation front is moving vertically with time, making a self- adaptive method advantageous computationally by allowing greater resolution at the front for a given number of degrees of freedom. Many numerical models have been developed for the solution of problems in unsaturated flow. A number are reviewed by van Gen~chten.~ These models include solutions based on a dynamic simulation language,' finite difference^^'^-^ (including a two-phase numerical model which allows the air pressure to vary"), finite element approximation^"-'^ and a multigrid finite difference s~lution'~ for the steady state problem. None of the numerical models mentioned above is self-adaptive. An adaptive model developed for unsaturated flow using a Eulerian-Langrangian finite element approach is discussed by Sorek and Brae~ter,'~ although no numerical results are presented. 027 1-209 1/90/030227-20$10.OO 0 1990 by John Wiley & Sons, Ltd.

[1] Organic liquid saturation distributions resulting from a simulated tetrachloroethene (PCE) spill were generated with alternative models of spatially varying aquifer properties for a statistically homogeneous, nonuniform sand aquifer. The distributions were analyzed to quantify DNAPL source zone characteristics and then incorporated as initial conditions for simulated PCE recovery using surfactant-enhanced aquifer remediation (SEAR). The predicted evolution of the spatial distribution of DNAPL saturations or source zone ‘‘architectures’’ and associated remediation efficiencies are strongly influenced by the spatial correlation of aquifer parameters and multiphase flow constitutive relationships. Model predictions suggest that removal of 60 to 99% of entrapped PCE can reduce dissolved contaminant concentration and mass flux under natural gradient conditions by approximately two orders of magnitude. Aqueous phase contaminant flux, however, does not vary consistently as a function of the percentage of DNAPL removed, and notable differences in flux evolution were observed for models incorporating correlated versus uncorrelated capillary entry pressure and permeability fields. Simulation results demonstrate that the application of alternative models of aquifer parameter spatial variability can influence predicted DNAPL infiltration, entrapment, and recovery, even for relatively homogeneous aquifers of the type investigated here. Results also demonstrate potential benefits, in the form of reduced mass flux, accruing from partial mass removal that may not be readily predicted from analyses relying on simplified conceptual models for DNAPL source zone architecture or aquifer flow fields. INDEX TERMS: 1829 Hydrology: Groundwater hydrology; 1832 Hydrology: Groundwater transport; 1831 Hydrology: Groundwater quality; KEYWORDS: contamination mass flux, DNAPL remediation, DNAPL source zone, heterogeneity, nonuniformity

Two-dimensional multiphase flow and transport simulators were refined and used to numerically investigate the entrapment and dissolution behavior of tetrachloroethylene (PCE) in heterogeneous porous media containing spatial variations in wettability. Measured hydraulic properties, residual saturations, and dissolution parameters were employed in these simulations. Entrapment was quantified using experimentally verified hydraulic property and residual saturation models that account for hysteresis and wettability variations. The nonequilibrium dissolution of PCE was modeled using independent estimates of the film mass transfer coefficient and interfacial area for entrapped and continuous (PCE pools or films) saturations. Flow simulations demonstrate that the spatial distribution of PCE is highly dependent on subsurface wettability characteristics that create differences in PCE retention mechanisms and the presence of subsurface capillary barriers. For a given soil texture, the maximum and minimum PCE infiltration depth was obtained when the sand had intermediate (an organic-wet mass fraction of 25%) and strong (water- or organic-wet) wettability conditions, respectively. In heterogeneous systems, subsurface wettability variations were also found to enhance or diminish the performance of soil texture-induced capillary barriers. The dissolution behavior of PCE was found to depend on the soil wettability and the spatial PCE distribution. Shorter dissolution times tended to occur when PCE was distributed over large regions due to an increased access of flowing water to the PCE. In heterogeneous systems, capillary barriers that produced high PCE saturations tended to exhibit longer dissolution times.

Summary Succinylcholine is a commonly used depolarizing muscle relaxant in general endotracheal anesthesia. The degradation of succinylcholine is accomplished by the human serum based enzyme pseudocholinesterase. Availability of pseudocholinesterase within the human being can be deficient as a result of an inherited or acquired cause. This case report will describe a female patient who was diagnosed with an acquired pseudocholinesterase deficiency.