1,531 research outputs found

    Synthesis and Characterization of [Fe(Htrz)\u3csub\u3e2\u3c/sub\u3e(trz)](BF\u3csub\u3e4\u3c/sub\u3e)] Nanocubes

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    Compounds that exhibit spin-crossover (SCO) type behavior have been extensively investigated due to their ability to act as molecular switches. Depending on the coordinating ligand, in this case 1H-1,2,4-triazole, and the crystallite size of the SCO compound produced, the energy requirement for the spin state transition can vary. Here, SCO [Fe(Htrz)2(trz)](BF4)] nanoparticles were synthesized using modified reverse micelle methods. Reaction conditions and reagent ratios are strictly controlled to produce nanocubes of 40–50 nm in size. Decreases in energy requirements are seen in both thermal and magnetic transitions for the smaller sized crystallites, where, compared to bulk materials, a decrease of as much as 20 °C can be seen in low to high spin state transitions

    Beta-glucan reflects liver injury after preservation and transplantation in dogs.

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    Graft failure and extrahepatic organ complications, which frequently develop after transplantation, may be related to inflammatory mediators stimulated by endotoxin (ET). The role of endotoxemia after liver transplantation is controversial and may depend upon differences in the ET assay method used in the various contradicting studies. While the standard Limulus amebocyte lysate (LAL) is reactive for ET and beta-glucan, a novel turbidimetric assay method enables separate determinations of ET and beta-glucan. Beagle dogs undergoing orthotopic liver transplantation were divided into two groups. In Group I (n = 6) the grafts were transplanted immediately and in Group II (n = 6) grafts were preserved for 48 h in University of Wisconsin (UW) solution. Animals received cyclosporine immunosuppression and were followed for 14 days. Daily measurements of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were performed. Samples for ET and beta-glucan measurement were collected serially and processed using the turbidimetric assay method. While no graft failure was seen in Group I, three of six Group II animals died from graft failure within 1 day after transplantation. Preservation and reperfusion injury was much more severe in the Group II grafts than in Group I grafts. While endotoxemia could not be detected, postoperative beta-glucan levels (undetectable pretransplant) were seen in both groups. Beta-glucan levels were much higher in Group II grafts than in Group I grafts, and correlated with the severity of liver damage. In conclusion, this study shows that beta-glucan, instead of ET, appears during the early posttransplant period. We believe that posttransplant elevation of beta-glucan is related to liver damage, especially endothelial damage by preservation and reperfusion

    Ultrafast High-Energy Micro-Supercapacitors Based On Open-Shell Polymer-Graphene Composites

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    Micro-supercapacitors are poised to serve as on-chip power sources for electronics. However, the challenge to simultaneously increase their power, energy, and lifetime demands new material combinations beyond current carbon-based systems. Here, we demonstrate that electro-deposition of an open-shell conjugated polymer with reduced graphene oxide achieves electrodes with capacitance up to 186 mF cm−2 (372 F cm−3). The extended delocalization within the open-shell polymer stabilizes redox states and facilitates a 3 V wide potential window, while the hierarchical electrode structure promotes ultrafast kinetics. The micro-supercapacitor shows a high power density of 227 mW cm−2 with an energy density of 10.5 μWh cm−2 and stability of 84% capacitance retention after 11,000 cycles. These attributes allow operation at 120 Hz for fast charging and alternating current (AC) line filtering applications, which may be suitable to replace bulky electrolytic capacitors or serve as high-endurance energy storage for wireless electronics

    Expert Statements on the Standard of Care in Critically Ill Adult Patients With Atypical Hemolytic Uremic Syndrome.

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    A typical hemolytic uremic syndrome (aHUS) presents similarly to thrombotic thrombocytopenic purpura (TTP) and other causes or conditions with thrombotic microangiopathy (TMA), such as disseminated intravascular coagulation or sepsis. Similarity in clinical presentation may hinder diagnosis and optimal treatment selection in the urgent setting in the ICU. However, there is currently no consensus on the diagnosis or treatment of aHUS for ICU specialists. This review aims to summarize available data on the diagnosis and treatment strategies of aHUS in the ICU to enhance the understanding of aHUS diagnosis and outcomes in patients managed in the ICU. To this end, a review of the recent literature (January 2009-March 2016) was performed to select the most relevant articles for ICU physicians. Based on the paucity of adult aHUS cases overall and within the ICU, no specific recommendations could be formally graded for the critical care setting. However, we recognize a core set of skills required by intensivists for diagnosing and managing patients with aHUS: recognizing thrombotic microangiopathies, differentiating aHUS from related conditions, recognizing involvement of other organ systems, understanding the pathophysiology of aHUS, knowing the diagnostic workup and relevant outcomes in critically ill patients with aHUS, and knowing the standard of care for patients with aHUS based on available data and guidelines. In conclusion, managing critically ill patients with aHUS requires basic skills that, in the absence of sufficient data from patients treated within the ICU, can be gleaned from an increasingly relevant literature outside the ICU. More data on critically ill patients with aHUS are needed to validate these conclusions within the ICU setting

    Dynamic and volumetric variables reliably predict fluid responsiveness in a porcine model with pleural effusion

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    Background: The ability of stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) for prediction of fluid responsiveness in presence of pleural effusion is unknown. The aim of the present study was to challenge the ability of SVV, PPV and GEDV to predict fluid responsiveness in a porcine model with pleural effusions. Methods: Pigs were studied at baseline and after fluid loading with 8 ml kg−1 6% hydroxyethyl starch. After withdrawal of 8 ml kg−1 blood and induction of pleural effusion up to 50 ml kg−1 on either side, measurements at baseline and after fluid loading were repeated. Cardiac output, stroke volume, central venous pressure (CVP) and pulmonary occlusion pressure (PAOP) were obtained by pulmonary thermodilution, whereas GEDV was determined by transpulmonary thermodilution. SVV and PPV were monitored continuously by pulse contour analysis. Results: Pleural effusion was associated with significant changes in lung compliance, peak airway pressure and stroke volume in both responders and non-responders. At baseline, SVV, PPV and GEDV reliably predicted fluid responsiveness (area under the curve 0.85 (p<0.001), 0.88 (p<0.001), 0.77 (p = 0.007). After induction of pleural effusion the ability of SVV, PPV and GEDV to predict fluid responsiveness was well preserved and also PAOP was predictive. Threshold values for SVV and PPV increased in presence of pleural effusion. Conclusions: In this porcine model, bilateral pleural effusion did not affect the ability of SVV, PPV and GEDV to predict fluid responsiveness

    Admission of advanced lung cancer patients to intensive care unit: A retrospective study of 76 patients

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    <p>Abstract</p> <p>Background</p> <p>Criteria for admitting patients with incurable diseases to the medical intensive care unit (MICU) remain unclear and have ethical implications.</p> <p>Methods</p> <p>We retrospectively evaluated MICU outcomes and identified risk factors for MICU mortality in consecutive patients with advanced lung cancer admitted to two university-hospital MICUs in France between 1996 and 2006.</p> <p>Results</p> <p>Of 76 included patients, 49 had non-small cell lung cancer (stage IIIB n = 20; stage IV n = 29). In 60 patients, MICU admission was directly related to the lung cancer (complication of cancer management, n = 30; cancer progression, n = 14; and lung-cancer-induced diseases, n = 17). Mechanical ventilation was required during the MICU stay in 57 patients. Thirty-six (47.4%) patients died in the MICU. Three factors were independently associated with MICU mortality: use of vasoactive agents (odds ratio [OR] 6.81 95% confidence interval [95%CI] [1.77-26.26], p = 0.005), mechanical ventilation (OR 6.61 95%CI [1.44-30.5], p = 0.015) and thrombocytopenia (OR 5.13; 95%CI [1.17-22.5], p = 0.030). In contrast, mortality was lower in patients admitted for a complication of cancer management (OR 0.206; 95%CI [0.058-0.738], p = 0.015). Of the 27 patients who returned home, four received specific lung cancer treatment after the MICU stay.</p> <p>Conclusions</p> <p>Patients with acute complications of treatment for advanced lung cancer may benefit from MCIU admission. Further studies are necessary to assess outcomes such as quality of life after MICU discharge.</p

    Topology and Ground State Control In Open-Shell Donor-Acceptor Conjugated Polymers

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    Donor-acceptor (DA) conjugated polymers (CPs) with narrow bandgaps and open-shell (diradical) character represent an emerging class of materials whose rich behavior emanates from their collective electronic properties and diminished electron pairing. However, the structural and electronic heterogeneities that define these materials complicate bandgap control at low energies and connections linking topology, exchange interactions, and (opto)electronic functionality remain nascent. To address these challenges, we demonstrate structurally rigid and strongly π-conjugated copolymers comprised of a solubilizing thiadiazoloquinoxaline acceptor and cyclopenta[2,1-b:3,4-b′]dithiophene or dithieno[3,2-b:2′,3′-d]thiophene donors. Atom-specific substitution modulates local aromatic character within the donor resulting in dramatic differences in structural, physicochemical, electronic, and magnetic properties of the polymers. These long-range π-mediated interactions facilitate control between low-spin aromatic and high-spin quinoidal forms. This work provides a strategy to understand the evolution of the electronic structure within DA CPs, control the ground state spin multiplicity, tune spin-spin interactions, and articulate the emergence of their novel properties

    Intensive care of the cancer patient: recent achievements and remaining challenges

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    A few decades have passed since intensive care unit (ICU) beds have been available for critically ill patients with cancer. Although the initial reports showed dismal prognosis, recent data suggest that an increased number of patients with solid and hematological malignancies benefit from intensive care support, with dramatically decreased mortality rates. Advances in the management of the underlying malignancies and support of organ dysfunctions have led to survival gains in patients with life-threatening complications from the malignancy itself, as well as infectious and toxic adverse effects related to the oncological treatments. In this review, we will appraise the prognostic factors and discuss the overall perspective related to the management of critically ill patients with cancer. The prognostic significance of certain factors has changed over time. For example, neutropenia or autologous bone marrow transplantation (BMT) have less adverse prognostic implications than two decades ago. Similarly, because hematologists and oncologists select patients for ICU admission based on the characteristics of the malignancy, the underlying malignancy rarely influences short-term survival after ICU admission. Since the recent data do not clearly support the benefit of ICU support to unselected critically ill allogeneic BMT recipients, more outcome research is needed in this subgroup. Because of the overall increased survival that has been reported in critically ill patients with cancer, we outline an easy-to-use and evidence-based ICU admission triage criteria that may help avoid depriving life support to patients with cancer who can benefit. Lastly, we propose a research agenda to address unanswered questions

    Assessment of Future Remnant Liver Function Using Hepatobiliary Scintigraphy in Patients Undergoing Major Liver Resection

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    Tc-99m-mebrofenin hepatobiliary scintigraphy (HBS) was used as a quantitative method to evaluate liver function. The aim of this study was to compare future remnant liver function assessed by Tc-99m-mebrofenin hepatobiliary scintigraphy with future remnant liver volume in the prediction of liver failure after major liver resection. Computed tomography (CT) volumetry and Tc-99m-mebrofenin hepatobiliary scintigraphy were performed prior to major resection in 55 high-risk patients, including 30 patients with parenchymal liver disease. Liver volume was expressed as percentage of total liver volume or as standardized future remnant liver volume. Receiver operating characteristic (ROC) curve analysis was performed to identify a cutoff value for future remnant liver function in predicting postoperative liver failure. Postoperative liver failure occurred in nine patients. A liver function cutoff value of 2.69%/min/m(2) was calculated by ROC curve analysis. Tc-99m-mebrofenin hepatobiliary scintigraphy demonstrated better sensitivity, specificity, and positive and negative predictive value compared to future remnant liver volume. Using Tc-99m-mebrofenin hepatobiliary scintigraphy, one cutoff value suffices in both compromised and noncompromised patients. Preoperative Tc-99m-mebrofenin hepatobiliary scintigraphy is a valuable technique to estimate the risk of postoperative liver failure. Especially in patients with uncertain quality of the liver parenchyma, Tc-99m-mebrofenin HBS proved of more value than CT volumetr
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