Reactivity control of nitrate-incorporating octadecavanadates by changing the oxidation state and metal substitution.

Clarification and control of the active sites at the atomic/molecular level are important to develop nanocatalysts. The catalytic performance of two oxidation states of nitrate-incorporating octadecavanadates, [V18O46(NO3)]5- (V18) and [V18O46(NO3)]4- (V18ox), and a copper-substituted one, [Cu2V16O44(NO3)]5- (Cu2V16), in selective oxidation was investigated. Both V18 and V18ox possessed the same double-helical structures and one of two tetravalent vanadium sites of V18 was oxidized in V18ox. The comparison of the mobility of the incorporated nitrate reveals that tetravalent vanadium centres show stronger interaction with the incorporated anions than pentavalent ones. The oxidation reaction with V18ox proceeded more smoothly with tert-BuOOH as an oxidant than that with V18. The reactivity and selectivity of the oxidation of 2-cyclohexen-1-ol were different among the derivatives. V18ox showed the higher reactivity with 72% selectivity to epoxide. With V18, reactivity was lower but higher selectivity to epoxide was achieved. In the presence of Cu2V16, 2-cyclohexen-1-one was selectively obtained with 81% selectivity. The order of the reactivity for cyclooctene was V18ox, V18 and Cu2V16. These results shows that the cap part of the double-helix acts as the active site. Even though the vanadium-oxygen species exhibit the same structures, the catalytic properties can be controlled by changing the valence of vanadium and metal substitution.

Integration of Kupffer cells into human iPSC-derived liver organoids for modeling liver dysfunction in sepsis.

Maximizing the potential of human liver organoids (LOs) for modeling human septic liver requires the integration of innate immune cells, particularly resident macrophage Kupffer cells. In this study, we present a strategy to generate LOs containing Kupffer cells (KuLOs) by recapitulating fetal liver hematopoiesis using human induced pluripotent stem cell (hiPSC)-derived erythro-myeloid progenitors (EMPs), the origin of tissue-resident macrophages, and hiPSC-derived LOs. Remarkably, LOs actively promote EMP hematopoiesis toward myeloid and erythroid lineages. Moreover, supplementing with macrophage colony-stimulating factor (M-CSF) proves crucial in sustaining the hematopoietic population during the establishment of KuLOs. Exposing KuLOs to sepsis-like endotoxins leads to significant organoid dysfunction that closely resembles the pathological characteristics of the human septic liver. Furthermore, we observe a notable functional recovery in KuLOs upon endotoxin elimination, which is accelerated by using Toll-like receptor-4-directed endotoxin antagonist. Our study represents a comprehensive framework for integrating hematopoietic cells into organoids, facilitating in-depth investigations into inflammation-mediated liver pathologies.

Effect of Smoke Evacuator on Reduction of Volatile Organic Compounds and Particles in Surgical Smoke: A Randomized Controlled Trial.

BACKGROUND: Surgical smoke is an occupational health problem and is increasingly recognized as a potential source of virus transmission. Dedicated smoke evacuators are used to protect against surgical smoke exposure. We tested the hypothesis that using smoke evacuators would reduce volatile organic compounds and the number of particles in surgical smoke during the laparotomy procedure. STUDY DESIGN: A randomized, double-blind clinical trial was conducted in patients undergoing laparotomy from June 11, 2021, to March 30, 2022, to compare the effectiveness of smoke evacuators with a control (registration, UMIN000044250). The primary outcome was a change in the acetaldehyde level. Secondary outcomes were changes in the formaldehyde level and particle count assessed by the particle size of 0.3, 0.5, 1.0, and 5.0 nm. RESULTS: A total of 42 patients were randomized and assessed (smoke evacuator group, n = 22 vs control group, n = 20). The acetaldehyde level was significantly lower in the smoke evacuator group than in the control group: mean (95% CI), 10.6 (3.7 to 17.5) vs 47.2 (19.9 to 74.5) µg/m 3 , p < 0.001. Similarly, the formaldehyde level was 72.2% lower in the smoke evacuator group than in the control group. Particle counts by each particle size category were 80% to 95% lower in the smoke evacuator group than in the control group (all, p < 0.001). CONCLUSIONS: Dedicated smoke evacuators reduced the level of acetaldehyde and formaldehyde, and the number of particles in surgical smoke, minimizing the potential exposure to volatile organic compounds and particle matters during surgery.

A data-informed timeline for hospital discharge with a reasonably low risk of unplanned readmission after open and minimally invasive liver resections.

BACKGROUND: Postoperative complications following liver resection remain high, ranging from 20% to 50%. Patients are hospitalized for a certain period of time following liver resection because of the risk of postoperative complications. We hypothesized that the risk of complications decreases with each complication-free postoperative day after open and minimally invasive liver resections and can be stratified using a recently reported three-level complexity classification. METHODS: Patients undergoing first liver resection without concomitant other organ resections between 2006 and 2019 were included. The three-level complexity classification was used to categorize liver resection procedures into grades I-III. We assessed the rate of cumulative postoperative complications from the time of liver resection to the time of post-hepatectomy complications (≥ Clavien-Dindo grade II). RESULTS: Of the 911 patients included, 200 underwent resection of grade I procedures, 185 underwent resection of grade II procedures, and 526 underwent resection of grade III procedures. The risks of post-hepatectomy complications changed over time and were stratified by surgical complexity. For patients at the time of liver resection, the estimated 30-day complication rate was 21.8% for open grade I resection, 26.7% for open grade II resection, 38.4% for open grade III resection, 8.6% for laparoscopic grade I resection, and 12.5% for laparoscopic grade II resection. For patients without complications at 7 days, the estimated 30-day complication rate decreased to 2.1% for open grade I, 9.2% for open grade II, 17.6% for open grade III, 1.3% for laparoscopic grade I, and 4.5% for laparascopic grade II. CONCLUSIONS: The post-hepatectomy complication risks were stratified by surgical complexity, liver resection approach, and the period without complication after liver resection.

Mechanistic insights into template-driven polyoxovanadate self-assembly: the role of internal and external templates.

The self-assembly of molecular metal oxides, polyoxometalates (POMs), can be controlled using internal or, more rarely, external templates. Here, we explore how the interplay between internal templates (halides, oxoanions) and organic external templates (protonated cyclene species) affect the self-assembly of a model polyoxovanadate cluster, [V12O32X]n- (X = Cl-, Br-, NO3-). A combination of crystallographic analyses, spectroscopic studies and in situ as well as solid-state 51V NMR spectroscopy provide critical insights into the initial formation of an intermediate vanadate species formed during the process. Structural and spectroscopic studies suggest that a direct interaction between internal and external templates allows tuning of the internal template position within the cluster cavity. These insights form the basis for further developing the template-driven synthetic chemistry of polyoxovanadates.

Evaluation of fibrinogen concentration by clot firmness using a dielectric blood coagulation test system.

PURPOSE: To determine if fibrinogen concentration can be evaluated by dielectric permittivity changes in dielectric blood coagulation testing (DBCM) during cardiovascular surgery with cardiopulmonary bypass (CPB). METHODS: We performed a single-center prospective observational study at a university hospital. One hundred patients undergoing cardiovascular surgery with CPB were enrolled. Whole-blood samples were obtained after weaning from CPB, and dielectric clot strength (DCS) was measured by intrinsic pathway testing with or without heparinase in DBCM. The FIBTEM test was performed during rotational thromboelastometry using the same samples, and maximum clot firmness (MCF) was evaluated. Spearman's correlation analysis was performed, and receiver operating characteristics (ROC) curve analyses were used to evaluate the performance of hypofibrinogenemia detection. RESULTS: DCS showed a strong positive correlation with plasma fibrinogen concentration (Rs = 0.76, P < 0.0001). The area under the ROC curve for evaluating plasma fibrinogen concentration < 200 mg/dL was 0.91 (95% confidence interval (CI) 0.85-0.97) for DCS, compared with 0.88 (95% CI 0.81-0.94) for FIBTEM MCF. The optimal cutoff value of DCS was 17.0 (sensitivity 94%, specificity 80%). CONCLUSIONS: DCS variables showed a significantly strong correlation with plasma fibrinogen concentration, and the diagnostic performance for hypofibrinogenemia was comparable to that for FIBTEM MCF. This novel methodology has the potential to provide a point-of-care test with sufficient accuracy for the detection of perioperative hypofibrinogenemia during cardiovascular surgery with CPB.

Synthesis of Water-Soluble Planar Cobalt(II), Nickel(II), and Copper(II) Hydroxo Clusters Using a (1,4,7-Triazacyclononane)cobalt(III) Complex as a Hydrolysis-Terminating Group.

We report on a group of planar cobalt(II), nickel(II), and copper(II) hydroxo clusters that have a definite composition and are water-soluble: [{Co(tacn)(OH)2}6Co7(OH)12](NO3)2(CF3SO3)6·10H2O (1), [{Co(tacn)(OH)2}6Ni7(OH)12](NO3)2(CF3SO3)6·10H2O (2a), [{Co(tacn)(OH)2}6Ni7(OH)12](BNPP)8·6CH3NO2·8H2O [2b; BNPP = bis(p-nitrophenyl)phosphate], [{Co(tacn)(OH)2}12Ni16(OH)26(OH2)2](SO4)4(CF3SO3)10·30H2O (3a), [{Co(tacn)(OH)2}12Ni16(OH)26(OH2)2](SO4)8(CF3SO3)2·44H2O (3b), [{Co(tacn)(OH)2}2Co2(OH)2(OH2)4](SO4)(CF3SO3)2·4H2O (4), [{Co(tacn)(OH)2}2Ni2(OH)2(OH2)4](SO4)(CF3SO3)2·4H2O (5), and [{Co(tacn)(OH)2}4Cu4(OH)6](ClO4)6·5H2O (6), where tacn is 1,4,7-triazacyclononane. The peripheral of each metal hydroxo cluster plane is chemically protected by the coordination of {CoIII(tacn)(OH)2}+ groups to prevent further hydrolysis. These clusters were synthesized by the reaction of an equimolar amount of [Co(tacn)(OH2)3]3+ and cobalt, nickel, or copper salt at pH values in the range of 6.0-12.0. The structure of the cation in compounds 1, 2a or 2b, 4, and 5 is relevant to the surface structure of the cobalt phosphate and nickel borate oxygen-evolution catalysts; in particular, the Co7(OH)12 core in 1. Moreover, the arrangement of M7(OH)12 in 1 and 2a or 2b and Cu4(OH)6 in 6 represents the solid-state structures of the (111) face of the cubic CoO or NiO and the (002) plane of Cu(OH)2, respectively. Extended X-ray absorption fine structure spectra of an aqueous solution of 1, 2a, 4, and 5 exhibit well-resolved peaks at the first and second coordination spheres due to the M-O and M···M distances, respectively; the solution-state bond distances were estimated, and they agreed well with the bond distances in the solid-state structures.

Selective Formation of Intramolecular Hydrogen-Bonding Palladium(II) Complexes with Nucleosides Using Unsymmetrical Tridentate Ligands.

Three palladium(II) complexes with amino-amidato-phenolato-type tridentate ligands were synthesized and characterized by 1H NMR spectroscopy and X-ray crystallography. The strategic arrangement of a hydrogen-bond donor and acceptor adjacent to the substitution site of the PdII complex allowed the selective coordination of nucleosides. Among two pyrimidine-nucleosides, cytidine and 5-methyluridine, cytidine was successfully coordinated to the PdII complex while 5-methyluridne was not. On the other hand, both purine-nucleosides, adenosine and guanosine, were coordinated to the PdII complex. As purines have several coordination sites, adenosine afforded three kinds of coordination isomers expected from the three different donors. However, guanosine afforded a sole product according to the ligand design such that the formation of double intramolecular hydrogen-bond strongly induced the specific coordination by N1-position of guanine moiety. Furthermore, the preference of the nucleosides was evaluated by scrambling reactions. It was found that the preference of guanosine is nearly twice as high as adenosine and cytidine, owing to the three-point interaction of a coordination bond and two hydrogen bonds. These results show that the combination of a coordination and hydrogen bonds, which is reminiscent of the Watson-Crick base pairing, is an effective tool for the precise recognition of nucleosides.

Human Pluripotent Stem Cell-Derived Hepatocyte-Like Cells and Organoids for Liver Disease and Therapy.

Liver disease is a global health issue that has caused an economic burden worldwide. Organ transplantation is the only effective therapy for end-stage liver disease; however, it has been hampered by a shortage of donors. Human pluripotent stem cells (hPSCs) have been widely used for studying liver biology and pathology as well as facilitating the development of alternative therapies. hPSCs can differentiate into multiple types of cells, which enables the generation of various models that can be applied to investigate and recapitulate a range of biological activities in vitro. Here, we summarize the recent development of hPSC-derived hepatocytes and their applications in disease modeling, cell therapy, and drug discovery. We also discuss the advantages and limitations of these applications and critical challenges for further development.

Synthesis of cyanooxovanadate and cyanosilylation of ketones.

The cyanosilylation was performed by using metavanadate catalysts, and in situ measurements revealed the formation of [VO2(CN)3]2- and [VO4TMS2]- under reaction conditions. The reaction of [VO2(CN)3]2-, trimethylsilyl cyanide (TMSCN), and water afforded [VO4TMS2]- and CN-, which reacted with ketones to yield the corresponding cyanohydrin trimethylsilyl ethers over [VO2(CN)3]2-. Compound [VO2(CN)3]2- showed high catalytic performance for cyanosilylation of various carbonyl compounds. In the case of n-hexanal, turnover frequency reached up to 250 s-1.

Isolation of a Nitromethane Anion in the Calix-Shaped Inorganic Cage.

A calix-shaped polyoxometalate, [V12O32]4- (V12), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of an anion. The highly-reactive cyanate is smoothly trapped by V12 to form [V12O32(CN)]5-. In the CH3NO2 solution, cyanate abstracts protons from CH3NO2, and the resultant CH2NO2- is stabilized in V12 to form [V12O32(CH2NO2)]5- (V12(CH2NO2)). A crystallographic analysis revealed the double-bond characteristic short bond distance of 1.248 Å between the carbon and nitrogen atoms in the nitromethane anion in V12. 1H and 13C NMR studies showed that the nitromethane anion in V12 must not be exchanged with the nitromethane solvent. Thus, the V12 container restrains the reactivity of anionic species.

Induced Fitting and Polarization of a Bromine Molecule in an Electrophilic Inorganic Molecular Cavity and Its Bromination Reactivity.

Dodecavanadate, [V12 O32 ]4- (V12), possesses a 4.4 Šcavity entrance, and the cavity shows unique electrophilicity. Owing to the high polarizability, Br2 was inserted into V12, inducing the inversion of one of the VO5 square pyramids to form [V12 O32 (Br2 )]4- (V12(Br2)). The inserted Br2 molecule was polarized and showed a peak at 185 cm-1 in the IR spectrum. The reaction of V12(Br2) and toluene yielded bromination of toluene at the ring, showing the electrophilicity of the inserted Br2 molecule. Compound V12(Br2) also reacted with propane, n-butane, and n-pentane to give brominated alkanes. Bromination with V12(Br2) showed high selectivity for 3-bromopentane (64 %) among the monobromopentane products and preferred threo isomer among 2-,3-dibromobutane and 2,3-dibromopenane. The unique inorganic cavity traps Br2 leading the polarization of the diatomic molecule. Owing to its new reaction field, the trapped Br2 shows selective functionalization of alkanes.

Effects of neural stem cell transplantation in Alzheimer's disease models.

Currently there are no therapies for treating Alzheimer's disease (AD) that can effectively halt disease progression. Existing drugs such as acetylcholinesterase inhibitors or NMDA receptor antagonists offers only symptomatic benefit. More recently, transplantation of neural stem cells (NSCs) to treat neurodegenerative diseases, including AD, has been investigated as a new therapeutic approach. Transplanted cells have the potential to replace damaged neural circuitry and secrete neurotrophic factors to counter symptomatic deterioration or to alter lesion protein levels. However, since there are animal models that can recapitulate AD in its entirety, it is challenging to precisely characterize the positive effects of transplanting NSCs. In the present review, we discuss the types of mouse modeling system that are available and the effect in each model after human-derived NSC (hNSC) or murine-derived NSC (mNSC) transplantation. Taken together, results from studies involving NSC transplantation in AD models indicate that this strategy could serve as a new therapeutic approach.

Artificial bioinorganic clusters of dinuclear 3d-transition metal ions coordinated by an inorganic coordination ligand.

A new biologically relevant cubane-type artificial inorganic ligand was developed to support 3d-transition metal ions of Mn(II), Co(II), Ni(II), Zn(II), Fe(III), and also In(III). All of the reactions produce dinuclear cationic clusters of [({Co(tacn)}2HMo3O13∙H2O){M(H2O)2}]2n+ (M = Mn2+ (4Mn), Co2+ (4Co), Ni2+ (4Ni), Zn2+ (4Zn), n = 2; M = Fe3+ (5), In3+ (6), n = 4), where tacn is the abbreviation of 1,4,7-triazacyclononane ligand. Clusters 4 do not dissolve in any solvents at all to prevent the recrystallization or the further characterization whereas the high solubility of clusters 5 and 6 allowed us to characterize the solution state properties. The dinuclear cores are separated at a fixed-distance in the range of 5.66-5.77 Šfor M(II) complexes and 5.45-5.65 Šfor M(III) complexes. Each 3d-transition metal ion is supported by two pairs of cis-oxido groups from a cubane unit formed by CoMo3O3(OH) group, and remaining two sites on the 3d-transition metal centers are occupied by two water molecules. The hydroxido group on the cubane unit provides an interaction route through bifurcated hydrogen bondings between dinuclear centers. Three consecutive stepwise reduction waves were observed at -0.73, -0.91, and -1.16 mV vs Fc+/Fc for 5 in cyclic voltammetry and the comparison with the redox inactive In3+ complex revealed that two iron centers are interacted each other through the inorganic ligand which gave a reduction wave observed at -0.91 mv vs Fc+/Fc.

Evaluation of the chemo- and shape-selective association of a bowl-type dodecavanadate cage with an electron-rich group.

The host-guest interaction between a half spherical-type dodecavanadate (V12) and a neutral molecule guest was evaluated by monitoring the flip of a VO5 unit caused by the presence or absence of a guest in the cavity of V12. In N,N-dimethylformamide (DMF), V12 adopted the guest-free form (V12-free). By the addition of several guest molecules, such as acetonitrile, nitromethane, and dichloromethane, the structural conversion to the guest-inserted form (V12(guest)) was observed with the affinity constants of 137 ± 10 M-1, 0.14 ± 0.1 M-1, and 0.15 ± 0.1 M-1, respectively. In the case of 1,2-dichloroethane, 1,2-dibromoethane, and 1,2-diiodoethane, the constants were 35 ± 5 M-1, 114 ± 5 M-1, and 2.1 ± 0.5 M-1, respectively, suggesting that the bromo group is the best fit to the cavity of the bowl. A cyclic carbonate, 5- and 6-membered lactones, cyclobutanone, and hexanal were inserted into the V12 host, while a non-cyclic carbonate, non-cyclic and 7-membered cyclic ester, a ketone with a 5-membered ring, and benzaldehyde showed no effect on the guest insertion. The V12 host preferred to hold a guest with an electron-rich group, and the bowl-type structure showed the unique shape-selective interaction with the guest.

Synthesis and structural characterization of tube-type tetradecavanadates.

By the reaction of ammonium perchlorate with anion-incorporated bowl-type dodecavanadates, viz. [V12O32(X)]5- [X = N3- (1), OCN- and NO3-], tube-type tetradecavanadates, viz. (NH4)7[V14O38(X)] [X = N3- (2), OCN- (3) and NO3- (4)] were synthesized. The crystal structures of penta(tetraethylammonium) azidododecavanadate nitromethane monosolvate, (C8H20N)5[V12O32(N3)]·CH3NO2, 1, heptaammonium azidotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(N3)]·6C2H6OS, 2, heptaammonium cyanatotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(OCN)]·6C2H6OS, 3, and heptaammonium nitratotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(NO3)]·6C2H6OS, 4, were determined. The tube consists of two layers of V7 rings with a guest anion at the centre. The distances between the incorporated anions and the nearest V atoms are 3.058 (3), 3.039 (6) and 2.811 (9) Šfor 2, 3 and 4, respectively, showing that the incorporated anions are stabilized via noncovalent interactions. Two ammonium cations cap both ends of the tube to stabilize the structures via hydrogen-bonding interactions. Linear OCN- and N3- anions sit on the twofold rotation axes of the tube frameworks and the triangular plane of the NO3- anion deviates from the equatorial plane of the tube by ca 30°.

Solid-State Umbrella-type Inversion of a VO5 Square-Pyramidal Unit in a Bowl-type Dodecavanadate Induced by Insertion and Elimination of a Guest Molecule.

Design of cavities for a target molecule and the elucidation of the corresponding host-guest interactions are important for molecular manipulation. A discrete dodecavanadate bowl, [V12 O32 ]4- (V12), with an entrance diameter of 4.4 Šand an electron-rich guest at the center of the bowl, was stabilized by electrostatic interactions. A characteristic of V12 is a solid-state polytopal rearrangement during guest elimination and recapture. A guest-free dodecavanadate, [V12 O32 ]4- (V12-free), was prepared by removal of the guest from CH2 Cl2 -inserted V12 under vacuum at 50 °C. Single-crystal X-ray analysis revealed that one of the VO5 square pyramids at the bottom of V12-free was inverted to fill the void of the bowl cavity. The exposure of V12-free to the guest molecule vapors of CH2 Cl2 , 1,2-dichloroethane, MeNO2 , MeCN, and MeBr resulted in the selective insertion of the guest to reform the guest-inserted V12 structure. Whereas CO2 could be inserted in the V12 bowl, CH4 and CO could not.

Strategic Isolation of a Polyoxocation Mimicking Vanadium(V) Oxide Layered-Structure by Stacking of [H2V2O8]4- Anions Bridged by (1,4,7-Triazacyclononane)Co(III) Complexes.

An isolation of a vanadium(V) oxide cluster mimicking V2O5 layered structure was achieved formulated as [{Co(tacn)}4V4O12(OH)4]4+ (1) (tacn = 1,4,7-triazacyclononane). From the 51V NMR spectra of the reaction mixtures, we optimized the reaction condition in terms of a molar ratio of VO43- and [Co(tacn)(H2O)3]3+ as well as a pH value. Cluster 1 is stable in a wide range of pH values from 1.5 to 8.0, and the presence of multiple hydrogen bondings in the structure is a unique feature. In the X-ray analysis of cluster 1, the V⋯ V distances are classified into two groups of relatively shorter distances (2.978(1) Å) and longer interactions (3.554(1) Å), and it is a good model of the substructure of V2O5 bulk material. As far as we know, this is a first example of an isolation of mixed-metal cluster including a unit of V2O5 structure by a stack of two layers of [H2V2O8]4-, although cubic V4O4 cubane-type clusters are well known. The solid sample of compound 1-Cl and 1-Br shows reversible thermochromic behavior accompanied by crystal to amorphous transformation upon hydration-dehydration process.

Synthesis of cationic molybdenum-cobalt heterometallic clusters protected against hydrolysis by macrocyclic triazacyclononane complexes.

Four kinds of cobalt-polyoxomolybdenum clusters were synthesized by a combination of polyoxomolybdates and a Co-tacn (tacn = 1,4,7-triazacyclononane) complex. The heterometallic polynuclear clusters were obtained by the reaction of Na2MoO4 and [Co(tacn)(H2O)3](CF3SO3)3·H2O in water. The peripherals of polyoxomolybdates are capped by thermodynamically stable [Co(tacn)]3+ protecting groups to prevent further hydrolysis and condensation reactions. Intra-molecular hydrogen bonds between N-H groups on tacn and oxygen atoms on the molybdate core contribute to the stability of the complexes in water. Under the optimized synthetic conditions, the molar ratios of Na2MoO4 and [Co(tacn)(H2O)3](CF3SO3)3·H2O were adjusted to 1 : 0.3, 1 : 0.9, or 1 : 1.5, producing [{Co(tacn)}2Mo3O12]·2NaCF3SO3·7H2O (1), [{Co(tacn)}4H2Mo7O27](CF3SO3)2·13H2O (2), and [{Co(tacn)}4H3Mo4O17](CF3SO3)5·6H2O (3), respectively. As one of the most important factors, the adjustments of the pH values by changing the molar ratio enabled us to isolate these clusters. The presence of pyridine produces a neutral complex, [Co2(tacn)2(pyridine)Mo5O18]·4.5H2O (4) containing a lacunary Lindqvist-type polyoxomolybdate. The synthesis of complexes 2-4 is also possible starting from cluster 1, implying that 1 is a precursor for the formation of 2-4 in aqueous solution. Complexes 2-4 have a common structural building block, [{Co(tacn)}2Mo3O13], in each of the cluster units. The 1H NMR spectra of 2 and 3 in aqueous solution show multiple splitting patterns of methylene signals on tacn ligands according to the chemical environments indicated by the crystallographic structure. The 59Co NMR spectrum of cluster 3 in CH3NO2 has two signals from two different Co units with a 3 : 1 integration ratio ensuring the structural integrity in solution. The broadening of one of the signals for the 59Co NMR spectrum of cluster 3 in water as a protic solvent reveals the presence of the deprotonation equilibrium of the acidic protons on the cluster framework in water.

Simultaneous assessment of blood coagulation and hematocrit levels in dielectric blood coagulometry.

BACKGROUND: In a whole blood coagulation test, the concentration of any in vitro diagnostic agent in plasma is dependent on the hematocrit level but its impact on the test result is unknown. OBJECTIVE: The aim of this work was to clarify the effects of reagent concentration, particularly Ca2+, and to find a method for hematocrit estimation compatible with the coagulation test. METHODS: Whole blood coagulation tests by dielectric blood coagulometry (DBCM) and rotational thromboelastometry were performed with various concentrations of Ca2+ or on samples with different hematocrit levels. DBCM data from a previous clinical study of patients who underwent total knee arthroplasty were re-analyzed. RESULTS: Clear Ca2+ concentration and hematocrit level dependences of the characteristic times of blood coagulation were observed. Rouleau formation made hematocrit estimation difficult in DBCM, but use of permittivity at around 3 MHz made it possible. The re-analyzed clinical data showed a good correlation between permittivity at 3 MHz and hematocrit level (R2=0.83). CONCLUSIONS: Changes in the hematocrit level may affect whole blood coagulation tests. DBCM has the potential to overcome this effect with some automated correction using results from simultaneous evaluations of the hematocrit level and blood coagulability.