Determining if the prognostic nutritional index can predict outcomes in community acquired bacterial pneumonia.

BACKGROUND: The Prognostic Nutritional Index (PNI) uses albumin levels and total lymphocyte count to predict the relationship between immune-nutritional state and prognosis in a variety of diseases, however it has not been studied in community acquired bacterial pneumonia (CABP). We conducted a historical cohort study to determine if there was an association between PNI and clinical outcomes in patients with CABP. METHODS: We reviewed 204 adult patients with confirmed CABP, and calculated admission PNI and Neutrophil-to-Lymphocyte Ratio (NLR). A comparative analysis was performed to determine the association of these values, as well as other risk factors, with the primary outcomes of 30-day readmissions and death. RESULTS: Of the 204 patients, 56.9% (116) were male, 48% (98) were black/African American and the mean age was 63.2 ± 16.1 years. The NLR was neither associated with death nor 30-day readmission. The mean PNI in those who survived was 34.7 ± 4.5, compared to 30.1 ± 6.5, in those who died, p < 0.001. From multivariable analysis after controlling for the Charlson score and age, every one-unit increase in the PNI decreased the risk of death by 13.6%. The PNI was not associated with readmissions. CONCLUSIONS: These findings suggest that poor immune and nutritional states, as reflected by PNI, both contribute to mortality, with a significant negative correlation between PNI and death in CABP. PNI was predictive of mortality in this patient cohort; NLR was not. Monitoring of albumin and lymphocyte count in CABP can provide a means for prevention and early intervention.

Neural networks for large eddy simulations of wall-bounded turbulence: numerical experiments and challenges.

We examine the application of neural network-based methods to improve the accuracy of large eddy simulations of incompressible turbulent flows. The networks are trained to learn a mapping between flow features and the subgrid scales, and applied locally and instantaneously-in the same way as traditional physics-based subgrid closures. Models that use only the local resolved strain rate are poorly correlated with the actual subgrid forces obtained from filtering direct numerical simulation data. We see that highly accurate models in a priori testing are inaccurate in forward calculations, owing to the preponderance of numerical errors in implicitly filtered large eddy simulations. A network that accounts for the discretization errors is trained and found to be unstable in a posteriori testing. We identify a number of challenges that the approach faces, including a distribution shift that affects networks that fail to account for numerical errors.

A Rare Case of Rapidly Progressive Extragonadal Mature Cystic Teratoma Presenting With Chest Pain.

Mature cystic teratomas represent the most prevalent subtype of germ cell tumors affecting the ovaries. Typically, these neoplasms are benign and characterized by a slow growth pattern. Nevertheless, malignant transformation of these tumors is a rare event that may occur. Despite their typically indolent behavior, some cases may exhibit rapid growth rates and give rise to a variety of complications, including rupture and consequent manifestation of a wide range of clinical signs and symptoms. This report details the case of a 49-year-old woman who presented to the hospital with a chief complaint of chest pain. The onset of her symptoms occurred several days prior to admission and was associated with fatigue without shortness of breath. Imaging studies, including computed tomography angiography and magnetic resonance imaging of the chest, revealed a mediastinal mass measuring 5.9 x 7.4 cm in a cross-sectional area that displayed features consistent with a mature cystic teratoma, including the presence of soft tissue, fat, fluid, and areas of calcification. Notably, a prior computed tomography scan of the chest, performed 20 months before her presentation, did not reveal any evidence of masses. The patient subsequently underwent successful robot-assisted resection of the mediastinal mass, with complete resolution of her symptoms. Histopathologic examination of the excised mass confirmed the absence of malignancy.

Hemophagocytic Lymphohistiocytosis in a Patient With Human Immunodeficiency Virus.

Hemophagocytic lymphohistiocytosis (HLH) is a rare and aggressive disorder that is often underdiagnosed due to its similarities in other forms of shock, most notably septic shock. In this case report, we discuss a patient who has a history of HIV presenting with altered mental status and cytopenias, ultimately going into shock and passing away. We initially thought we would be dealing with a case of septic shock, but a diagnostic workup during his hospital case lead to a diagnosis of hemophagocytic lymphohistiocytosis. This case illustrates how patients with HLH present very similar to septic shock and how to manage patients with this very aggressive disease.

Light Chain Amyloidosis Presenting as a Septic Shock: A Case Report and Review of Literature.

Light chain (AL) amyloidosis is a plasma cell dyscrasia that results in an overproduction of immunoglobulins of the lambda or kappa light chains. These monoclonal ALs begin to form fibrils with each other and exert their toxic effect by depositing in different organs around the body. Disease presentation is indistinct, but it is ideal to diagnose this disorder before end-organ damage is caused. Once the diagnosis of AL amyloidosis is confirmed, the best treatment is autologous stem cell transplantation once a candidate is deemed fit for it; however, there are other chemotherapy agents whose patients can be administered until they undergo stem cell transplantation. In this case presentation and systematic review of AL amyloidosis, we discuss a patient who presented with septic shock and further workup leading to a diagnosis of advanced-stage amyloidosis. We also take a deeper look at AL amyloidosis providing a comprehensive review of the disease process and its treatment options.

Privacy preserving Generative Adversarial Networks to model Electronic Health Records.

Hospitals and General Practitioner (GP) surgeries within National Health Services (NHS), collect patient information on a routine basis to create personal health records such as family medical history, chronic diseases, medications and dosing. The collected information could be used to build and model various machine learning algorithms, to simplify the task of those working within the NHS. However, such Electronic Health Records are not made publicly available due to privacy concerns. In our paper, we propose a privacy-preserving Generative Adversarial Network (pGAN), which can generate synthetic data of high quality, while preserving the privacy and statistical properties of the source data. pGAN is evaluated on two distinct datasets, one posing as a Classification task, and the other as a Regression task. Privacy score of generated data is calculated using the Nearest Neighbour Adversarial Accuracy. Cosine similarity scores of synthetic data from our proposed model indicate that the data generated is similar in nature, but not identical. Additionally, our proposed model was able to preserve privacy while maintaining high utility. Machine learning models trained on both synthetic data and original data have achieved accuracies of 74.3% and 74.5% respectively on the classification dataset; while they have attained an R2-Score of 0.84 and 0.85 on synthetic and original data of the regression task respectively. Our results, therefore, indicate that synthetic data from the proposed model could replace the use of original data for machine learning while preserving privacy.

CYP2C9 and 3A4 play opposing roles in bioactivation and detoxification of diphenylamine NSAIDs.

Diphenylamine NSAIDs are taken frequently for chronic pain conditions, yet their use may potentiate hepatotoxicity risks through poorly characterized metabolic mechanisms. Our previous work revealed that seven marketed or withdrawn diphenylamine NSAIDs undergo bioactivation into quinone-species metabolites, whose reaction specificities depended on halogenation and the type of acidic group on the diphenylamine. Herein, we identified cytochromes P450 responsible for those bioactivations, determined reaction specificities, and estimated relative contributions of enzymes to overall hepatic bioactivations and detoxifications. A qualitative activity screen revealed CYP2C8, 2C9, 2C19, and 3A4 played roles in drug bioactivation. Subsequent steady-state studies with recombinant CYPs recapitulated the importance of halogenation and acidic group type on bioactivations but importantly, showed patterns unique to each CYP. CYP2C9, 2C19 and 3A4 bioactivated all NSAIDs with CYP2C9 dominating all possible bioactivation pathways. For each CYP, specificities for overall oxidative metabolism were not impacted significantly by differences in NSAID structures but the values themselves differed among the enzymes such that CYP2C9 and 3A4 were more efficient than others. When considering hepatic CYP abundance, CYP2C9 almost exclusively accounted for diphenylamine NSAID bioactivations, whereas CYP3A4 provided a critical counterbalance favoring their overall detoxification. Preference for either outcome would depend on molecular structures favoring metabolism by the CYPs as well as the influence of clinical factors altering their expression and/or activity. While focused on NSAIDs, these findings have broader implications on bioactivation risks given the expansion of the diphenylamine scaffold to other drug classes such as targeted cancer therapeutics.

Impacts of diphenylamine NSAID halogenation on bioactivation risks.

Diphenylamine NSAIDs are highly prescribed therapeutics for chronic pain despite causing symptomatic hepatotoxicity through mitochondrial damage in five percent of patients taking them. Differences in toxicity are attributed to structural modifications to the diphenylamine scaffold rather than its inherent toxicity. We hypothesize that marketed diphenylamine NSAID substituents affect preference and efficiency of bioactivation pathways and clearance. We parsed the FDA DILIrank hepatotoxicity database and modeled marketed drug bioactivation into quinone-species metabolites to identify a family of seven clinically relevant diphenylamine NSAIDs. These drugs fell into two subgroups, i.e., acetic acid and propionic acid diphenylamines, varying in hepatotoxicity risks and modeled bioactivation propensities. We carried out steady-state kinetic studies to assess bioactivation pathways by trapping quinone-species metabolites with dansyl glutathione. Analysis of the glutathione adducts by mass spectrometry characterized structures while dansyl fluorescence provided quantitative yields for their formation. Resulting kinetics identified four possible bioactivation pathways among the drugs, but reaction preference and efficiency depended upon structural modifications to the diphenylamine scaffold. Strikingly, diphenylamine dihalogenation promotes formation of quinone metabolites through four distinct metabolic pathways with high efficiency, whereas those without aromatic halogen atoms were metabolized less efficiently through two or fewer metabolic pathways. Overall metabolism of the drugs was comparable with bioactivation accounting for 4-13% of clearance. Lastly, we calculated daily bioload exposure of quinone-species metabolites based on bioactivation efficiency, bioavailability, and maximal daily dose. The results revealed stratification into the two subgroups; propionic acid diphenylamines had an average four-fold greater daily bioload compared to acetic acid diphenylamines. However, the lack of sufficient study on the hepatotoxicity for all drugs prevents further correlative analyses. These findings provide critical insights on the impact of diphenylamine bioactivation as a precursor to hepatotoxicity and thus, provide a foundation for better risk assessment in drug discovery and development.

Significance of Multiple Bioactivation Pathways for Meclofenamate as Revealed through Modeling and Reaction Kinetics.

Meclofenamate is a nonsteroidal anti-inflammatory drug used in the treatment of mild-to-moderate pain yet poses a rare risk of hepatotoxicity through an unknown mechanism. Nonsteroidal anti-inflammatory drug (NSAID) bioactivation is a common molecular initiating event for hepatotoxicity. Thus, we hypothesized a similar mechanism for meclofenamate and leveraged computational and experimental approaches to identify and characterize its bioactivation. Analyses employing our XenoNet model indicated possible pathways to meclofenamate bioactivation into 19 reactive metabolites subsequently trapped into glutathione adducts. We describe the first reported bioactivation kinetics for meclofenamate and relative importance of those pathways using human liver microsomes. The findings validated only four of the many bioactivation pathways predicted by modeling. For experimental studies, dansyl glutathione was a critical trap for reactive quinone metabolites and provided a way to characterize adduct structures by mass spectrometry and quantitate yields during reactions. Of the four quinone adducts, we were able to characterize structures for three of them. Based on kinetics, the most efficient bioactivation pathway led to the monohydroxy para-quinone-imine followed by the dechloro-ortho-quinone-imine. Two very inefficient pathways led to the dihydroxy ortho-quinone and a likely multiply adducted quinone. When taken together, bioactivation pathways for meclofenamate accounted for approximately 13% of total metabolism. In sum, XenoNet facilitated prediction of reactive metabolite structures, whereas quantitative experimental studies provided a tractable approach to validate actual bioactivation pathways for meclofenamate. Our results provide a foundation for assessing reactive metabolite load more accurately for future comparative studies with other NSAIDs and drugs in general. SIGNIFICANCE STATEMENT: Meclofenamate bioactivation may initiate hepatotoxicity, yet common risk assessment approaches are often cumbersome and inefficient and yield qualitative insights that do not scale relative bioactivation risks. We developed and applied innovative computational modeling and quantitative kinetics to identify and validate meclofenamate bioactivation pathways and relevance as a function of time and concentration. This strategy yielded novel insights on meclofenamate bioactivation and provides a tractable approach to more accurately and efficiently assess other drug bioactivations and correlate risks to toxicological outcomes.

Short-Term Non-Infectious Outcomes After a Pars Plana Intravitreal Antibiotic-Steroid Injection of Triamcinolone, Moxifloxacin, and Vancomycin During Cataract Surgery versus a Standard Postoperative Topical Regimen.

PURPOSE: To compare short-term non-infectious clinical outcomes after cataract surgery with an intraoperative pars plana intravitreal antibiotic-steroid (IVAS) injection of triamcinolone, moxifloxacin, and vancomycin (TMV) versus a standard postoperative topical regimen. PATIENTS AND METHODS: A retrospective comparative case series of 1058 eyes (control = 487, treatment = 571) undergoing cataract surgery were included. Endpoints included best-corrected visual acuity (BCVA), intraocular pressure (IOP), and the unplanned use of anti-inflammatory topical medication in the postoperative period. The follow-up period ranged from 1 to 6 months. RESULTS: A final monocular BCVA of 20/25 or better was achieved in 78.8% and 87.4% of eyes in the control and treatment groups, respectively (p = 0.001). The overall incidence of an IOP spike (Δ ≥ 10 mm Hg) was not significantly different between the two groups (0.4% versus 1.9%, p = 0.027). The rates of persistent anterior chamber inflammation (PACI), rebound anterior chamber inflammation (RACI), and cystoid macular edema (CME) in the control and treatment groups were 8.0% vs 2.6% (p < 0.001), 6.4% vs 2.6% (p = 0.003), and 3.9% vs 4.7% (p = 0.511), respectively. The use of an IVAS injection of TMV conferred an increased risk of CME (odds ratio [OR] = 3.21, 95% confidence interval [CI] = 1.42 to 7.23) but no significant effect on the risk of PACI (OR = 0.34, 95% CI = 0.10 to 1.14) or RACI (OR = 0.52, 95% CI = 0.18 to 1.54) when compared to a topical regimen. CONCLUSION: An intraoperative IVAS injection after uncomplicated cataract surgery may be as safe and effective as a standard topical regimen in terms of postoperative IOP and anterior chamber inflammatory events, respectively. However, the efficacy of a TMV formulation for CME prophylaxis appears to be unsatisfactory. Future studies with prospective and randomized designs are needed to further evaluate this technique.

Effects of a Novel Adsorbent on Membrane Fouling by Natural Organic Matter in Drinking Water Treatment.

Irreversible fouling of water filtration membranes reduces filter longevity and results in higher costs associated with membrane maintenance and premature replacement. The search for effective pretreatment methods to remove foulants that tend to irreversibly foul membranes is ongoing. In this study, a novel adsorbent (Heated Aluminum Oxide Particles (HAOPs)) was deployed in a fully automated pilot system to remove natural organic matter (NOM) from the surface water source used at the UniVann water treatment plant (WTP) in Ullensaker County, Norway. The pilot plant treatment process consists of passing the water through a thin layer of HAOPs that has been deposited on a mesh support. The HAOPs layer acts as an active packed bed which removes NOM from the water. Fluxes around 120 L/m2/h (LMH) at transmembrane pressure (TMP) below 10.7 psi (0.7 bar) were achieved over production cycles excessing 12 h. Treatment achieved always >85% colour removal and effluent colour <5 mg Pt/L (the target of treatment), and always <0.01 NTU turbidity and non-detectable suspended solids in the permeate. The HAOPs mixture after saturated with NOM is easy to remove by disruption of the HAOPs by rinsing the mesh surface, and the sludge is easily dewatered to higher of dry solids content.

Efficient phosphorus removal from MBR effluent with heated aluminum oxide particles (HAOPs).

Biological processes and chemical precipitation in combination with polishing by granular media or membrane filtration can remove 90-95% of the phosphorus (P) from wastewater. However, reducing the concentration to levels near those in high-quality receiving waters requires additional advanced treatment, typically including adsorption onto specialty media. These processes are often costly, they can be hard to control when the P loading varies, and their effectiveness can be compromised by the presence of competing adsorbates in the water. In this work, a novel process that might mitigate or overcome some of these challenges was explored. In the process, water is treated by passage through micron-sized adsorbent particles (Heated Aluminum Oxide Particles, HAOPs) packed in a layer that is  < 1 mm thick, thus combining the attractive features of very small particles with those of flow through packed media. In laboratory tests using both synthetic feed and the effluent from an MBR at a full-scale wastewater treatment plant, the process removed P very efficiently until the HAOPs' capacity was nearly exhausted, at which point rapid breakthrough of P occurred. The removal capacity was proportional to the thickness of the HAOPs layer and declined by only ∼20% when SO42-, Cl-, and NO3- were all added to the MBR effluent at concentrations of 30 mM (2880, 1065, and 1860 mg/L, respectively). Increasing the solution pH from 7.0 to 8.5 had a similar effect, and increasing the flux of water through the adsorbent layer from 200 to 600 LMH had an even smaller effect (∼10% reduction in removal capacity). In 18 days of continuous pilot-scale operation at the treatment plant, the process performed well, achieving 99.5% P removal steadily during the final seven days of testing, during which the P concentration in the feed ranged from 4 to 9 mg/L. The process also removed 52% of the organic matter in the MBR effluent, as represented by UV254. The sludge generated by the process was extremely easy to dewater and dry.

A proteasome-resistant fragment of NIK mediates oncogenic NF-κB signaling in schwannomas.

Schwannomas are common, highly morbid and medically untreatable tumors that can arise in patients with germ line as well as somatic mutations in neurofibromatosis type 2 (NF2). These mutations most commonly result in the loss of function of the NF2-encoded protein, Merlin. Little is known about how Merlin functions endogenously as a tumor suppressor and how its loss leads to oncogenic transformation in Schwann cells (SCs). Here, we identify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-inducing kinase (NIK) as a potential drug target driving NF-κB signaling and Merlin-deficient schwannoma genesis. Using a genomic approach to profile aberrant tumor signaling pathways, we describe multiple upregulated NF-κB signaling elements in human and murine schwannomas, leading us to identify a caspase-cleaved, proteasome-resistant NIK kinase domain fragment that amplifies pathogenic NF-κB signaling. Lentiviral-mediated transduction of this NIK fragment into normal SCs promotes proliferation, survival, and adhesion while inducing schwannoma formation in a novel in vivo orthotopic transplant model. Furthermore, we describe an NF-κB-potentiated hepatocyte growth factor (HGF) to MET proto-oncogene receptor tyrosine kinase (c-Met) autocrine feed-forward loop promoting SC proliferation. These innovative studies identify a novel signaling axis underlying schwannoma formation, revealing new and potentially druggable schwannoma vulnerabilities with future therapeutic potential.

Insights and Model for Understanding Natural Organic Matter Adsorption onto Mixed Adsorbents.

Adsorption-based processes are commonly used to remove natural organic matter (NOM) from drinking water sources and thereby mitigate its impacts on other water treatment processes and the quality of the finished water. These processes are complicated by the fact that NOM comprises multiple fractions that can exhibit disparate adsorption behaviors. Prior modeling of NOM adsorption has invariably focused on systems with a single adsorbent, but results presented here demonstrate surprising and counterintuitive behavior in systems containing two or more adsorbents. Specifically, if the sequence of affinities of the different NOM fractions are the same for two adsorbents, then overall adsorption changes monotonically as one adsorbent is gradually replaced by the other. However, if the sequence differs for the two adsorbents, overall adsorption can increase even when the nominally stronger adsorbent is gradually replaced by the weaker one. This work demonstrates and explains such behavior for a particular mixture of adsorbents and introduces a mathematical model that illustrates how other mixtures might behave.

Arts-based palliative care training, education and staff development: A scoping review.

BACKGROUND: The experience of art offers an emerging field in healthcare staff development, much of which is appropriate to the practice of palliative care. The workings of aesthetic learning interventions such as interactive theatre in relation to palliative and end-of-life care staff development programmes are widely uncharted. AIM: To investigate the use of aesthetic learning interventions used in palliative and end-of-life care staff development programmes. DESIGN: Scoping review. DATA SOURCES: Published literature from 1997 to 2015, MEDLINE, CINAHL and Applied Social Sciences Index and Abstracts, key journals and citation tracking. RESULTS: The review included 138 studies containing 60 types of art. Studies explored palliative care scenarios from a safe distance. Learning from art as experience involved the amalgamation of action, emotion and meaning. Art forms were used to transport healthcare professionals into an aesthetic learning experience that could be reflected in the lived experience of healthcare practice. The proposed learning included the development of practical and technical skills; empathy and compassion; awareness of self; awareness of others and the wider narrative of illness; and personal development. CONCLUSION: Aesthetic learning interventions might be helpful in the delivery of palliative care staff development programmes by offering another dimension to the learning experience. As researchers continue to find solutions to understanding the efficacy of such interventions, we argue that evaluating the contextual factors, including the interplay between the experience of the programme and its impact on the healthcare professional, will help identify how the programmes work and thus how they can contribute to improvements in palliative care.

Innovative Visualizations Shed Light on Avian Nocturnal Migration.

Globally, billions of flying animals undergo seasonal migrations, many of which occur at night. The temporal and spatial scales at which migrations occur and our inability to directly observe these nocturnal movements makes monitoring and characterizing this critical period in migratory animals' life cycles difficult. Remote sensing, therefore, has played an important role in our understanding of large-scale nocturnal bird migrations. Weather surveillance radar networks in Europe and North America have great potential for long-term low-cost monitoring of bird migration at scales that have previously been impossible to achieve. Such long-term monitoring, however, poses a number of challenges for the ornithological and ecological communities: how does one take advantage of this vast data resource, integrate information across multiple sensors and large spatial and temporal scales, and visually represent the data for interpretation and dissemination, considering the dynamic nature of migration? We assembled an interdisciplinary team of ecologists, meteorologists, computer scientists, and graphic designers to develop two different flow visualizations, which are interactive and open source, in order to create novel representations of broad-front nocturnal bird migration to address a primary impediment to long-term, large-scale nocturnal migration monitoring. We have applied these visualization techniques to mass bird migration events recorded by two different weather surveillance radar networks covering regions in Europe and North America. These applications show the flexibility and portability of such an approach. The visualizations provide an intuitive representation of the scale and dynamics of these complex systems, are easily accessible for a broad interest group, and are biologically insightful. Additionally, they facilitate fundamental ecological research, conservation, mitigation of human-wildlife conflicts, improvement of meteorological products, and public outreach, education, and engagement.

A multi-spectral approach to differentiate the effects of adsorbent pretreatments on the characteristics of NOM and membrane fouling.

Pretreatment of feed water is widely applied to mitigate NOM-induced fouling of low-pressure membranes. This research investigated the effectiveness of two pretreatment modes for NOM removal by heated aluminum oxide particles (HAOPs) and the associated reductions in membrane fouling and trihalomethane (THM) formation potential. One mode, referred to here as pre-adsorption, is the conventional process in which adsorbent particles are added to and thoroughly mixed with the feed, after which the particles are separated from the water either upstream of or by the membrane. By contrast, in the pre-deposition mode, a thin layer of adsorbent particles is deposited on a support media (which could be the membrane) prior to passing feed through the layer and the membrane. Although both pretreatment methods remove similar amounts of DOC at the same adsorbent dose, pre-deposition is superior with respect to mitigating membrane fouling and reducing DBP formation. UV and fluorescence spectroscopy and HPSEC analysis indicate that a pre-deposited adsorbent layer removes more chromophores and low apparent molecular weight (AMW) material than pre-adsorption does. Based on absorbance ratios at selected wavelengths, a pre-deposited HAOPs layer removes more aromatic moieties than aliphatic carboxyls, especially at higher HAOPs doses. In addition, pre-deposition is more effective than pre-adsorption at reducing the THM formation potential. The results provide new insights into the interactions between HAOPs and NOM molecules and shed light on the significantly different effects of different adsorbent contacting modes on the fouling potential of the pretreated water.

NOM fractionation and fouling of low-pressure membranes in microgranular adsorptive filtration.

Membrane fouling by natural organic matter (NOM) was investigated in microgranular adsorptive filtration (µGAF) systems, in which a thin layer of adsorbent is predeposited on low-pressure membranes. The adsorbents tested included heated aluminum oxide particles (HAOPs), ion exchange (IX) resin, and powdered activated carbon (PAC). Size exclusion chromatography (SEC) separated the NOM into four apparent MW fractions with significant UV254. HAOPs and the IX resin performed almost identically with respect to removal of these fractions, and differently from PAC. However, while HAOPs and PAC reduced fouling substantially, IX resin did not, indicating that fouling could not be attributed to the NOM fractions detected by SEC. Rather, the key foulants appear to comprise a very small fraction of the NOM with almost no UV254 absorbance. Alginate, a strongly fouling surrogate for natural polysaccharides, is adsorbed effectively by HAOPs, but not by IX resin or PAC, suggesting that polysaccharides sometimes play a key role in membrane fouling by NOM.

Isolated innominate artery as a cause of subclavian steal and cerebral hemisphere atrophy.

A rare case of isolated innominate artery arising from a left persistent arterial duct with a right aortic arch is presented. Of interest in this case is the retrograde flow in the left carotid system, the history of developmental delay, and the magnetic resonance image (MRI) brain findings suggestive of asymmetric volume loss affecting the left cerebral hemisphere. The authors postulate a possible mechanism of subclavian steal.

New conceptualization and solution approach for the ideal adsorbed solution theory (IAST).

Despite the widespread use of the ideal adsorbed solution theory (IAST) to predict competitive adsorption of hydrophobic organic compounds from aqueous solutions, the underlying principles of the model are not widely understood. A new conceptualization is presented that treats the adsorbed phase as gas-like with a total surface pressure equal to the sum of the partial surface pressures of the adsorbed species. In this conceptualization, the key assumption of the IAST is reformulated as indicating that the partial surface pressure exerted by an adsorbate depends only on its adsorption density and a surface activity coefficient that depends on the total surface pressure. The parallels of the model parameters and assumptions with those in gas/liquid equilibrium facilitate a more intuitive understanding of the model concepts. This understanding, in turn, clarifies the reasons underlying the predictions of the IAST for limiting conditions where one adsorbate dominates the surface phase. Finally, a new solution algorithm is introduced that allows the model equations to be solved using a simple spreadsheet analysis in which onlytwo independent parameters need be evaluated regardless of the number of adsorbates in the system or the characteristics of the single-solute isotherms.