Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

Hydrothermal synthesis, characterization and gas adsorption study of a Zn(II) based 1D coordination polymer

Anew 1D co-ordination polymer [Zn(C10H2O8)(0.5) (C10S2N2H8)center dot 2H(2)O)](n) (1) has been synthesized by in situ formation of a 4-pyt (4-pyridinethiolate) ligand from 4,4'-pyridyldithiol precursor through reductive cleavage of the disulfide bond under hydrothermal conditions. Compound 1 possesses pendent 4-pyt ligands through a Zn-S bond which restricts the framework to expand dimensionality. The compound shows selective CO2 adsorption over N-2 at low temperatures

A copper based pillared-bilayer metal organic framework : its synthesis, sorption properties and catalytic performance

A new 2D pillared-bilayer flexible open metal organic framework {[Cu(tdc)(bpe)](n)center dot 2n(H2O)center dot n(MeOH)} (compound 1) [H(2)tdc = 2,5 thiophenedicarboxylic acid; bpe = 1,2-bis(4-pyridyl)ethane] has been synthesized through a solvent diffusion technique and structurally characterized. The structure analysis reveals that the tdc ligands formed bilayers with the Cu(II) ions along the b-direction and the layers are further pillared by bpe linkers and resulted in a 2D pillared-bilayer porous framework with a four connected uninodal sq1/Shubnikob tetragonal plane net with the Sch lfli symbol {4(4).6(2)}. The framework is enclosed with large square shaped channels (13.7 x 8.35 A(2)) along the bc-plane and the channels are occupied by guest solvent molecules. The adsorption studies reveal that compound 1 shows selective adsorption for CO2 over CH4 at room temperature and it also shows hysteretic sorption for a few protic solvents (H2O and EtOH) and a Type-1 isotherm for an aprotic solvent (CH3CN). The catalytic performance of compound 1 for Glaser type homo-coupling reactions has also been reported

Synthesis, characterisation, water adsorption and proton conductivity of three Cd(II) based luminescent metal-organic frameworks

Three hydrogen bonded three-dimensional (3D) metal-organic frameworks (MOFs) namely [Cd(L-tart)-(bpy)(H2O)](n)center dot 9n(H2O) (1), [Cd(D-tart)(bpy)(H2O)](n)center dot 9n(H2O) (2) and [Cd(DL-tart)(bpy)(H2O)](n)center dot 6n(H2O) (3) (tart = tartaric acid, bpy = 4,4-bipyridine) have been synthesized by the solvent diffusion technique at room temperature. Compounds 1 and 2 have been characterized by single crystal X-ray analysis, whereas the powder X-ray diffraction patterns show that the structural integrity of compound 3 is similar to 1 and 2. Structural analysis of 1 and 2 shows H-bonded homochiral 3D MOFs, fabricated by the hydrogen bonding interactions between the nearby 2D pillared-layer frameworks through the metal-bound water, metalbound carboxylate, free carboxylic acid and the hydroxy group of L-/D-tart. The absolute configuration of all the compounds was investigated by solid state circular dichroism (CD) spectroscopy, which signifies that 1 and 2 are enantiomers whereas 3 is racemic. The adsorption studies reveal that compounds 1-3 show a significant amount of uptake for water vapor (similar to 239 mL g(-1) for 1, similar to 240 mL g(-1) in 2, whereas 184 mL g(-1) for 3 at P/P-0 approximate to 1 bar) over other solvents (MeOH, EtOH) and an impedance measurement indicates that these compounds show proton conduction (1.3 x 10(-6) S cm(-1) in 1, 1.3 x 10(-6) S cm(-1) in 2 and 4.5 x 10(-7) S cm(-1) in 3) at a higher temperature (358 K) and at 95% relative humidity. The observed conductivity is explained by the so-called vehicle mechanism (activation energy (E-a) = 0.63-0.77 eV). Since all the compounds contain H3O+ cations in the interlayer space, the hydronium ions might act as vehicles to transport the protons in the interlayer space. The photoluminescence properties of all the compounds are also reported

Tuning CO2 uptake and reversible iodine adsorption in two isoreticular MOFs through ligand functionalization

The synthesis and characterization of two isoreticular metal-organic frameworks (MOFs), {[Cd(bdc)(4-bpmh)]}(n)center dot 2n(H2O) (1) and {[Cd(2-NH(2)bdc)(4-bpmh)]}(n)center dot 2n(H2O) (2) [bdc= benzene dicarboxylic acid; 2-NH(2)bdc= 2-amino benzene dicarboxylic acid; 4-bpmh= N, N-bis-pyridin-4-ylmethylene- hydrazine], are reported. Both compounds possess similar two-fold interpenetrated 3D frameworks bridged by dicarboxylates and a 4-bpmh linker. The 2D Cd-dicarboxylate layers are extended along the a-axis to form distorted square grids which are further pillared by 4-bpmh linkers to result in a 3D pillared-bilayer interpenetrated framework. Gas adsorption studies demonstrate that the amino-functionalized MOF 2 shows high selectivity for CO2 (8.4 wt% 273 K and 7.0 wt% 298 K) over CH4, and the uptake amounts are almost double that of non-functional MOF 1. Iodine (I2) adsorption studies reveal that amino-functionalized MOF 2 exhibits a faster I-2 adsorption rate and controlled delivery of I-2 over the non-functionalized homolog 1

Proton-conducting magnetic coordination polymers

Three isostructural lanthanide-based two- dimensional coordination polymers (CPs) {[Ln(2)(L)(3)(H2O)(2)](n)2nCH(3)OH)2nH(2)O} (Ln=Gd3+ (1), Tb3+ (2), Dy3+ (3); H2L=cyclobutane-1,1-dicarboxylic acid) were synthesized by using a low molecular weight dicarboxylate ligand and characterized. Single-crystal structure analysis showed that in complexes 1-3 lanthanide centers are connected by (3)-bridging cyclobutanedicarboxylate ligands along the c axis to form a rod-shaped infinite 1D coordination chain, which is further linked with nearby chains by (4)-connected cyclobutanedicarboxylate ligands to form 2D CPs in the bc plane. Viewing the packing of the complexes down the b axis reveals that the lattice methanol molecules are located in the interlayer space between the adjacent 2D layers and form H-bonds with lattice and coordinated water molecules to form 1D chains. Magnetic properties of complexes 1-3 were thoroughly investigated. Complex 1 exhibits dominant ferromagnetic interaction between two nearby gadolinium centers and also acts as a cryogenic magnetic refrigerant having a significant magnetic entropy change of -S-m=32.8Jkg(-1)K(-1) for H=7T at 4K (calculated from isothermal magnetization data). Complex 3 shows slow relaxation of magnetization below 10K. Impedance analysis revealed that the complexes show humidity-dependent proton conductivity (sigma=1.5x10(-5)Scm(-1) for 1, sigma=2.07x10(-4)Scm(-1) for 2, and sigma=1.1x10(-3)Scm(-1) for 3) at elevated temperature (>75 degrees C). They retain the conductivity for up to 10h at high temperature and high humidity. Furthermore, the proton conductivity results were correlated with the number of water molecules from the water-vapor adsorption measurements. Water-vapor adsorption studies showed hysteretic and two-step water vapor adsorption (182000Lg(-1) for 1, 184000Lg(-1) for 2, and 1874000Lg(-1) for 3) in the experimental pressure range. Simulation of water-vapor adsorption by the Monte Carlo method (for 1) confirmed the high density of adsorbed water molecules, preferentially in the interlayer space between the 2D layers

Exploration of structural topologies in metal-organic frameworks based on 3-(4-carboxyphenyl)propionic acid : their synthesis, sorption, and luminescent property studies

Four new compounds (two coordination polymers (CPs) and two metal organic frameworks (MOFs)), namely, [Zn(cpp)(H2O)](n) (1), [Cu(cpp)(4-bpmh)](n)center dot nH(2)O center dot nMeOH (2), [Cd-2(cpp)(2)(3-bpmh)(2)](n)4nH(2)O center dot 2nMeOH (3), and [Cd(cpp)(bpy)(H2O)(2)](n)center dot 2nH(2)O (4), have been synthesized through the slow diffusion technique using cpp ligand and different neutral linkers (H(2)cpp = 3-(4-carboxyphenyl)propionic acid, 4-bpmh = N,N-bis-pyridin-4-ylmethylene-hydrazine, 3-bpmh = N,N-bis-pyridin-3-ylmethylene-hydrazine, bpy = 4,4-bipyridine). Single crystal X-ray analysis of compounds 1-4 reveals their structural diversities which might have been generated due to both rigidity (aryl carboxylate) and flexibility (aliphatic carboxylates) of cpp ligands as well their bridging modes and the orientation of nitrogen atoms of the neutral linkers. In addition, the dihedral angle in the aliphatic carboxylates of cpp ligand is also playing an important role in directing the final structural arrangement. Compound 1 exhibits a uninodal 6-connected three-dimensional (3D) coordination polymer with point Schalfli symbol {3(3).5(9).6(3)} and shows an uncommon lcy; 6/3/c1 topological type. Compound 2 reveals a 6-connected uninodal 3D framework with point Schalfli symbol {4(8).6(6).8} and shows a rare rob topology. Compound 3 formed a 4-connected uninodal two-dimensional framework with point Schalfli symbol {4(4).6(2)} and displays a sql/Shubnikov tetragonal plane net topology, whereas 4 forms a one-dimensional CP which subsequently extended to 3D supramolecular networks through hydrogen bonding interactions. Gas adsorption studies reveal that compounds 1 and 2 show selective adsorption of CO2 over other gases (N-2, CH4) at low temperature, whereas 3 and 4 show no uptake. Vapor sorption studies reveal that compounds 1, 2, and 4 show high uptake capacities for H2O over MeOH and EtOH. Solid state luminescence studies of compounds 1, 3, and 4 display significant red shifts compared to free ligands

A family of three magnetic metal organic frameworks : their synthesis, structural, magnetic and vapour adsorption study

Three flexible metal-organic frameworks (MOFs) based on aldrithiol linker and pyromellitate ligand, namely, [Co(aldrithiol)(pyromellitate)(0.5)(H2O)(2)] n (1), [Ni-2(aldrithiol)(2)(pyromellitate)(H2O)(2)](n)center dot 2n(C2H5OH)center dot 11n(H2O) (2) and [Cu(aldrithiol) 2(pyromellitate)](n)center dot 2n(H2O)(3) have been synthesized through slow diffusion technique and characterized by structural, magnetic and adsorption studies. Single crystal X-ray studies show that compounds 1 and 3 have two-dimensional layered structures, whereas compound 2 adopts a threedimensional framework structure. The observed dimensionality change might be due to the different orientation of pyridine rings in the flexible aldrithiol linker and versatile bridging modes of the pyromellitate ligand. In 1 and 2, the pyromellitate ligand coordinates to the metal centre in a monodentate fashion {(K-1)-(K-1)-(K-1)(K-1)-mu 4} and in 3, it coordinates in {(K-1)-(K-1)-mu 2} fashion. The magnetic properties of 1-3 were investigated in detail and show weak antiferromagnetic coupling among the metal centres. Vapour sorption studies reveal that compounds 1 and 3 show high methanol vapour uptake, whereas compound 2 shows a decent amount of H2O adsorption. The dehydrated frameworks of 1-3 regenerate the as-synthesized framework structures upon exposure to water vapour

Synthesis and characterization of two lanthanide (Gd3+ and Dy3+)-based three-dimensional metal organic frameworks with squashed metallomacrocycle type building blocks and their magnetic, sorption, and fluorescence properties study

Two novel isostructural lanthanide- based three-dimensional (3D) metal organic frameworks (MOFs), [Ln(2)(pam)(3)(DMF)(2)(H2O)(2)](n). nDMF {Ln = Gd(1), Dy(2); H(2)pam = 4,4'-methylenebis[3-hydroxy-2-naphthalenecarboxylic acid]} using the pharmaceutical agent "pamoic acid (H(2)pam)" are synthesized for the first time. Single crystal structure analysis shows that the 3D framework originates from the self-assembly of lanthanide metallomacrocycles made of dumble-shaped basic secondary building units and having channels of sizes 17.427 X 15.163 angstrom (for 1) and 14.58 X 17.23 angstrom (for 2), respectively. In both the complexes, two eight-coordinated lanthanide centers are connected with six pamoate groups to give a paddle-wheel type building block. The arrangement of pamoates and lanthanides in the framework provokes both right- (P) and left-hand (M) helicity around the 21 screw axis. The magnetic measurements show that complex 1 acts as a cryogenic magnetic refrigerant having magnetic entropy change, -Delta S-m, of 17.25 J kg(-1) K-1(Delta H = 7 T at 3 K), and complex 2 shows slow relaxation of magnetization. The adsorption studies reveal that complexes 1 and 2 show selectivity toward CO2 sorption over other gases and exhibit high methanol vapor uptake (227 cm(3) g(-1) for 1 and 201 cm(3) g(-1) for 2). Solid state photoluminescence properties reveal that they are photoluminescent materials

Third-Generation Breathing Metal–Organic Framework with Selective, Stepwise, Reversible, and Hysteretic Adsorption Properties

A new 2D interdigitated and highly flexible, breathing metal–organic framework has been synthesized through a diffusion technique by using the aldrithiol linker and pyromellitate ligand. The compound shows selective, stepwise, reversible, and hysteretic adsorption properties for CO₂ gas and H₂O, MeOH, and CH₃CN vapors