1,132 research outputs found

    Fish oil-containing lipid emulsions in patients with sepsis

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    Lipid emulsions based on soybean oil have been an integral part of parenteral nutrition supplying n-6 fatty acids, with possible negative effects in critically ill patients. Newer lipid emulsions supply less n-6 fatty acids. In addition, fish oil-based lipids may be included in the lipid component of parenteral nutrition. While clinical benefits of lipid emulsions with a reduced fraction in n-6 lipids and the addition of fish oil have been described in postoperative patients, data are less clear in critically ill or septic patients. Recent data suggest that beneficial effects may be achieved when used early but clearly more data are needed to come to a definitive conclusion. The present commentary will highlight current data in critically ill and septic patients and the use of fish oil as a part of parenteral nutrition

    Halogen bonding in the crystal structures of 1,2-diiodo alkenes

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    Supramolecular templating techniques have been widely used to direct the formation of porous materials with the goal of introducing permanent mesoporosity. While surfactant-directed self-assembly has been exploited for inorganic materials such as titania, silica, organosilica, and zeolites, it has rarely been applied to metal-organic frameworks (MOFs) and coordination polymers. Here we introduce a new family of gemini surfactant-directed zinc imidazolates, referred to as mesostructured imidazolate frameworks (MIFs), and present a detailed study on the influence of different gemini-type surfactants on the formation mechanism and structures of the resulting zinc imidazolates. The proposed formation mechanism for MIF-type materials involves co-assembly and crystallization processes that yield lamellar mesostructured imidazolate frameworks. Understanding and controlling such processes also has implications for the syntheses of microporous zinc imidazolate framework (ZIF) materials, whose formation can be suppressed in surfactant-rich solutions, whereas formation of MIF materials is favored in the presence of surfactants and triggered by the addition of halogenides. Solid-state 2D 13C1H HETCOR NMR measurements on prototypic CTAB-directed MIF-1 establish that the head group moieties of the surfactant molecules interact strongly with the zinc-imidazolate-bromide sheets. Additionally, the NMR analyses suggest that MIF-1 has a significant fraction of surfactant molecules that are interdigitated between the zinc-imidazolate-bromide sheets with an antiparallel stacking arrangement, consistent with the high thermal and chemical stability of the MIF hybrid materials

    Halogen bonding in the crystal structures of 1,2-diiodo alkenes

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    Supramolecular templating techniques have been widely used to direct the formation of porous materials with the goal of introducing permanent mesoporosity. While surfactant-directed self-assembly has been exploited for inorganic materials such as titania, silica, organosilica, and zeolites, it has rarely been applied to metal-organic frameworks (MOFs) and coordination polymers. Here we introduce a new family of gemini surfactant-directed zinc imidazolates, referred to as mesostructured imidazolate frameworks (MIFs), and present a detailed study on the influence of different gemini-type surfactants on the formation mechanism and structures of the resulting zinc imidazolates. The proposed formation mechanism for MIF-type materials involves co-assembly and crystallization processes that yield lamellar mesostructured imidazolate frameworks. Understanding and controlling such processes also has implications for the syntheses of microporous zinc imidazolate framework (ZIF) materials, whose formation can be suppressed in surfactant-rich solutions, whereas formation of MIF materials is favored in the presence of surfactants and triggered by the addition of halogenides. Solid-state 2D 13C1H HETCOR NMR measurements on prototypic CTAB-directed MIF-1 establish that the head group moieties of the surfactant molecules interact strongly with the zinc-imidazolate-bromide sheets. Additionally, the NMR analyses suggest that MIF-1 has a significant fraction of surfactant molecules that are interdigitated between the zinc-imidazolate-bromide sheets with an antiparallel stacking arrangement, consistent with the high thermal and chemical stability of the MIF hybrid materials

    Spontaneous Reductive Elimination at Iridium(III) Induced by the Strong π‐Acceptor Ligand Trifluorophosphane

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    The reaction of the cyclometalated five‐coordinate 16 VE iridium(III) compound [IrCl(H)(P(tBu)2C6H4‐Îș2P,C)(P(tBu)2Ph)] (1) with the strong π‐acceptor ligand trifluorophosphane resulted quickly in the quantitative formation of the new iridium(I) complex trans‐[IrCl(PF3)(P(tBu)2Ph)2] (2). This unexpected spontaneous reductive elimination was already observed in reactions of 1 with the very strong π‐acceptor ligands CO and NO+. First indications during reactions of 1 with lesser strong π‐acceptor ligands like alkyl or arylphosphanes did not show this inversion behavior of the cyclometalation. The title species 2 was characterized by spectroscopic methods and its molecular structure in the crystal was confirmed by X‐ray crystallography

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    n-3 fatty acid-enriched parenteral nutrition regimens in elective surgical and ICU patients: a meta-analysis

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    Introduction: Previous studies and a meta-analysis in surgical patients indicate that supplementing parenteral nutrition regimens with n-3 polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is associated with improved laboratory and clinical outcomes in the setting of hyper-inflammatory conditions. Refined or synthetic fish oils are commonly used as a source of EPA and DHA. The objective of the present meta-analysis was to evaluate n-3 PUFA-enriched parenteral nutrition regimens in elective surgical and intensive care unit (ICU) patients.Methods: Medline was searched for randomized controlled trials comparing n-3 PUFA-enriched lipid emulsions with standard non-enriched lipid emulsions (i.e. soybean oil, MCT/LCT or olive/soybean oil emulsions) in surgical and ICU patients receiving parenteral nutrition. Extracted data were pooled by means of both random and fixed effects models, and subgroup analyses were carried forward to compare findings in ICU versus non-ICU patients.Results: A total of 23 studies (n = 1502 patients: n = 762 admitted to the ICU) were included. No statistically significant difference in mortality rate was found between patients receiving n-3 PUFA-enriched lipid emulsions and those receiving standard lipid emulsions (RR= 0.89; 0.59, 1.33), possibly reflecting a relatively low underlying mortality risk. However, n-3 PUFA-enriched emulsions are associated with a statistically and clinically significant reduction in the infection rate (RR =0.61; 0.45, 0.84) and the lengths of stay, both in the ICU (-1.92; -3.27, -0.58) and in hospital overall (-3.29; -5.13, -1.45). Other beneficial effects included reduced markers of inflammation, improved lung gas exchange, liver function, antioxidant status and fatty acid composition of plasma phospholipids, and a trend towards less impairment of kidney function.Conclusions: These results confirm and extend previous findings, indicating that n-3 PUFAs-enriched parenteral nutrition regimens are safe and effective in reducing the infection rate and hospital/ICU stay in surgical and ICU patients. © 2012 Pradelli et al.; licensee BioMed Central Ltd

    Crystal structure of 2-[chloro(4-methoxyphenyl)-methyl]-2-(4-methoxyphenyl)-5,5-dimethylcyclohexane-1,3-dione

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    In the title compound, C23H25ClO4, the cyclohexane ring adopts a chair conformation with the 4-methoxyphenyl substituent in an axial position and the chloro(4-methoxyphenyl) methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C-H center dot center dot center dot O contacts and strands along [100] and [010] established by further C-H center dot center dot center dot O and C-H center dot center dot center dot Cl contacts, respectively

    Crystal structure of (1S, 2R)-6,6-dimethyl-4,8-dioxo-2-phenylspiro[2.5] octane-1-carbaldehyde

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    In the title compound, C17H18O3, the two non-spiro C atoms of the cyclopropane ring bear a formyl and a phenyl substituent which are trans-oriented. In the crystal, molecules are linked by weak C-H center dot center dot center dot O and C-H center dot center dot center dot pi contacts resulting in a three-dimensional supramolecular structure

    Coinage Metal Complexes of Bis(quinoline-2-ylmethyl)phenylphosphine-Simple Reactions Can Lead to Unprecedented Results

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    The different coordination behavior of the flexible yet sterically demanding, hemilabile P,N ligand bis(quinoline-2-ylmethyl)phenylphosphine (bqmpp) towards selected Cu-I, Ag-I and Au-I species is described. The resulting X-ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN)(4)]BF4, compound 1 [Cu-2(bqmpp)(2)](BF4)(2) is obtained, wherein the copper(I) atoms display a distorted square planar and square pyramidal geometry. The steric demand and pi-stacking of the ligand allow for a short Cu...Cu distance (2.588(9) angstrom). Cu-I complex 2 [Cu4Cl3(bqmpp)(2)]BF4 contains a rarely observed Cu4Cl3 cluster, probably enabled by dichloromethane as the chloride source. In the cluster, even shorter Cu...Cu distances (2.447(1) angstrom) are present. The reaction of Ag[SbF6] with the ligand leads to a dinuclear compound (3) in solution as confirmed by P-31{H-1} NMR spectroscopy. During crystallization, instead of the expected phosphine complex 3, a tris(quinoline-2-ylmethyl)bisphenyl-phosphine (tqmbp) compound [Ag-2(tqmbp)(2)](SbF6)(2) 4 is formed by elimination of quinaldine. The Au(I) compound [Au-2(bqmpp)(2)]PF6 (5) is prepared as expected and shows a linear arrangement of two phosphine ligands around Au-I

    Blended Laboratories for Joining Technology

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    Laboratory training is an essential part of most Engineering Education programs and amplified by the Covid-19 crisis, educational institutions are increasingly exploring blended and online laboratories as an alternative or complement to pure on-side learning environments. In this paper, we report on the (re-) design, implementation and evaluation of a blended laboratory concept in joining technology. The laboratory consists of three interlinked pillars and builds conceptually on the flipped classroom approach. We evaluate student learning and satisfaction as well as teacher experiences in the new learning design based on student evaluations and performance data as well as teacher reflections. The results show that the new laboratory improved the average grade of students by 12% compared to the traditional set-up, which we attribute to the increase in active learning. Students also report high satisfaction with the new format and appreciate the flexibility and accessibility of the online learning materials. Qualitative analysis indicates, however, that successful participation in the flipped format is coupled to high degree of self-regulated learning skills. Further, teachers partly had difficulties to ensure active participation in the synchronous online sessions. Despite these issues, we conclude that the presented flipped laboratory concept is an excellent format to combine the advantages of online learning with the hands-on experience of physical laboratory work. By utilizing the benefits of online learning, this format reduces the time students spend passively listening to lectures and more than doubles the time spent on active learning and practice
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