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Concept: Sodium citrate

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Calcium plays an integral role in olfactory signal transduction, including feedback inhibition. Sodium citrate acts as a calcium sequestrant and when applied intranasally, reduces free calcium available for feedback inhibition, which should theoretically improve olfaction. We aimed to investigate the utility of intranasal sodium citrate in improving the olfactory function of hyposmic patients, by performing this prospective placebo controlled, single-blind trial.

Concepts: Better, Improve, Calcium, Olfaction, Sodium citrate

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OBJECTIVE To assess the effect of decreased platelet and WBC counts on platelet aggregation as measured by a multiple-electrode impedance aggregometer in dogs. ANIMALS 24 healthy dogs. PROCEDURES From each dog, 9 mL of blood was collected into a 10-mL syringe that contained 1 mL of 4% sodium citrate solution to yield a 10-mL sample with a 1:9 citrate-to-blood ratio. Each sample was then divided into unmanipulated and manipulated aliquots with progressively depleted buffy-coat fractions such that 2 to 3 blood samples were evaluated per dog. The Hct for manipulated aliquots was adjusted with autologous plasma so that it was within 2% of the Hct for the unmanipulated aliquot for each dog. All samples were analyzed in duplicate with a multiple-electrode impedance aggregometer following the addition of ADP as a platelet agonist. The respective effects of platelet count, plateletcrit, Hct, and WBC count on platelet aggregation area under the curve (AUC), aggregation, and velocity were analyzed with linear mixed models. RESULTS WBC count was positively associated with platelet AUC, aggregation, and velocity; blood samples with leukopenia had a lower AUC, aggregation, and velocity than samples with WBC counts within the reference range. Platelet count, plateletcrit, and Hct did not have an independent effect on AUC, aggregation, or velocity. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that WBC count was positively associated with platelet aggregation when ADP was used to activate canine blood samples for impedance aggregometry. That finding may be clinically relevant and needs to be confirmed by in vivo studies.

Concepts: Blood, Red blood cell, In vivo, Platelet, In vitro, Count, Complete blood count, Sodium citrate

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Viridiofungins are alkyl citrate natural products characterized by their inhibitory effects on squalene synthase and serine palmitoyl transferase. Their activities as broad-spectrum antifungal agents as well as blocking agents for the biosynthesis of sphingolipids have inspired the development of several approaches toward their stereoselective total synthesis. Structurally, these natural products are a family of hybrid molecules comprising a longer alkyl chain and a citric acid unit, rendering an asymmetric structure that is difficult to access. Herein, we summarize the synthetic approaches to this attractive class of natural products, including proficient synthetic strategies for constructing the densely and chirally functionalized citric acid unit with high polarity. Particular emphasis is placed on methods for furnishing stereogenic centers in the highly constrained carbon framework.The Journal of Antibiotics advance online publication, 27 September 2017; doi:10.1038/ja.2017.110.

Concepts: Amino acid, Acid, Chemical synthesis, Citric acid, Salt, Vinegar, Total order, Sodium citrate

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Hydrogels with good mechanical properties, excellent biocompatibility and designable shapes are of great importance for their biomedical applications. Herein, a series of high strength, biocompatible hydrogels have been synthesized by integrating sodium citrate into the thermally reversible chitosan/gelatin to form multiple physically crosslinking networks. Besides the ideal formability, a thermal etching or welding method has been developed to program the surface morphology and fabricate hydrogels with complicated shapes freely. More impressively, the special hollow “cup-shaped and tubular” structure has also been constructed by applying an interrupted gelation process in controlled ion crosslinking time and the subsequent dissolving process at 37°C in deionized water. The high strength, biocompatible hydrogels with special internal and external shape adjustable characters, potentially useful in vascular repair and substitutes of cartilage, may further broaden our understanding of the plasticity of the hydrogels.

Concepts: Water, Structure, Gel, Shape, Welding, Supreme Headquarters Allied Powers Europe, Thermal, Sodium citrate

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The 2013 ISTH-SSC guidelines for the standardization of light transmission aggregometry (LTA) were largely based on expert consensus, as studies directly comparing LTA methodologies were lacking. We experimentally tested the cogency of ISTH-SSC recommendations pertaining to use of anticoagulant, in particular whether: (1) buffered citrate (BC) is preferable to unbuffered citrate ©; (2) the two recommended concentrations of sodium citrate (109 and 129 mM) are equivalent in terms of platelet aggregation (PA). Blood from 16 healthy volunteers was collected into BC and C (109 and 129 mM). PA was measured by LTA in platelet-rich plasma (PRP) stimulated by adenosine diphosphate (ADP) (2 μM) immediately after PRP preparation and up to 4 hr after blood collection; pH and platelet counts in PRP were measured in parallel. pH in PRP increased with time up to about 8 for all anticoagulants, although it was lower in BC than in C at all times. In BC, PA was lower at 45 min, but equivalent at all other times. PA was higher and more stable in sodium citrate 109 mM than in 129 mM at all times. The extent of PA did not change for up to 2 hr after blood collection, and subsequently dramatically decreased. In contrast with ISTH-SSC recommendations, (1) BC does not show advantages compared to C; (2) 109 mM citrate is preferable to 129 mM, because it better supports PA; and (3) LTA studies should be completed within 2 hr of blood collection, instead of the recommended 4 hr.

Concepts: Blood, Thrombosis, Platelet, Anticoagulant, Thrombocytopenia, Adenosine diphosphate, Blood transfusion, Sodium citrate

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Surface-enhanced Raman scattering (SERS) has been widely used in the detection of targets and strongly depends on the interaction and the distance between the targets and nanoparticles. Herein, metal-organic frameworks (MOFs) were first easily synthesized on a large scale via a water bath method, especially Uio-66 and Uio-67. MOFs embedded with gold nanoparticles (AuNPs) for SERS enhancement were successfully fabricated via an impregnation strategy. The synthesized AuNPs/MOF-199, AuNPs/Uio-66, and AuNPs/Uio-67 composites, with LSPR properties and high adsorption capability of MOFs to preconcentrate the analytes close to the surface of the AuNPs, exhibited excellent SERS activity. The effects of the reducing concentrations of sodium citrate on the SERS activity, and the stability and reproducibility of the AuNP/MOFs have been discussed via the detection of acetamiprid. The SERS intensity enhanced by the composites was retained for more than 40 days under ambient conditions with the reducing concentrations of sodium citrate at 0.16%, 0.20%, and 0.16%. The limits of detection with the signal/noise ratio higher than 3 at the characteristic peak 632 cm(-1) were 0.02 μM, 0.009 μM, and 0.02 μM for acetamiprid. Most interestingly, the AuNP/MOF-199 composites, whose morphology was long tube sheet, exhibited excellent SERS activity. These novel composites with high sensitivity, stability, and reproducibility provide a new route for the detection of pesticides via the SERS technology.

Concepts: Nanoparticle, Scattering, Nanotechnology, Gold, Raman scattering, Sodium citrate

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A new approach to carrageenan quantitation was described. The method consists in titration of carrageenan solution by Methylene Blue dye or Toluidine Blue dye solution until a certain absorbance value. The optimal wavelengths are 660nm and 640nm when titrating with Methylene Blue dye and Toluidine Blue dye, respectively. Rectilinear calibration plots (R(2)>0.996) provide carrageenan determination in the concentration range from 2 to 60mg/L with relative standard deviation from 1 to 5%. The proposed method is simple and feasible in use due to optical dip probe providing in situ absorbance measurements. The proposed way of end-point recognition as pre-set voltage is applicable with any automatic titrator. The method was tested on model jelly dessert sachet. No interference was registered from typical ingredients of jellies such as sucrose, citric acid, sodium citrate, malic acid, potassium sorbate as well as blue colorant. The neutral polysaccharides such as guar gum and locust bean gum have insignificant interference when their content is fivefold as compared to that of carrageenan.

Concepts: Acid, Glucose, Citric acid cycle, Citric acid, E number, Acids in wine, Sorbic acid, Sodium citrate

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A species sensitivity distribution (SSD) for engineered nanomaterials (ENMs) ranks the tested species according to their sensitivity to a certain ENM. An SSD may be used to estimate the maximum acceptable concentrations of ENMs for the purpose of environmental risk assessment. To construct SSDs for metal-based ENMs, more than 1800 laboratory derived toxicity records of metallic ENMs from >300 publications or open access scientific reports were retrieved. SSDs were developed for the metallic ENMs grouped by surface coatings, sizes, shapes, exposure durations, light exposures, and different toxicity endpoints. It was found that PVP- and sodium citrate- coatings enhance the toxicity of Ag ENMs as concluded from the relevant SSDs. For the Ag ENMs with different size ranges, differences in behavior and/or effect were only observed at high exposure concentrations. The SSDs of Ag ENMs separated by both shape and exposure duration were all nearly identical. Crustaceans were found to be the most vulnerable group to metallic ENMs. In spite of the uncertainties of the results caused by limited data quality and availability, the present study provided novel information about building SSDs for distinguished ENMs and contributes to the further development of SSDs for metal-based ENMs.

Concepts: Duration, Shape, Supreme Headquarters Allied Powers Europe, Sodium citrate

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Chitin nanocrystal (ChiNC) is a promising reinforcing nanofiller for biomedical polymers. However, its self-aggregation characteristics caused processing difficulty in developing ChiNC-based nanocomposites. Herein, a new degradable crosslinked bioelastomer, designated as poly(1,8-octanediol-co-Pluronic F127 citrate) (POFC) was synthesized by melt polycondensation of citric acid, 1,8-octanediol, and Pluronic F127. In comparison to poly(1,8-octanediol citrate) (POC), POFC pre-polymer exhibited self-emulsifying property. Once ChiNC was introduced into the emulsion, a ChiNC stabilized Pickering emulsion was formed. Coupled with a facile green emulsion casting/evaporation method, the ChiNC ultimately reinforced ChiNC/POFC nanocomposite elastomer was fabricated. The presence of F127 segments endowed POFC with better hydrophilicity and shorter degradation time relative to POC. The incorporation of ChiNC into POFC network led to highly increased tensile modulus and strength. In vitro cytotoxicity tests indicated that the ChiNC/POFC elastomer nanocomposite had a good cytocompatibility and it appeared as a potential biomaterial for tissue engineering application.

Concepts: Acid, Nanomaterials, Emulsion, Materials science, Tensile strength, Citric acid, Elastomer, Sodium citrate

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Glutamate decarboxylase (GAD) is the sole enzyme that synthesizes γ-aminobutyric acid through the irreversible decarboxylation of L-glutamate. In this study, the purification and characterization of an unreported GAD from a novel strain of Enterococcus raffinosus TCCC11660 were investigated. The native GAD from E. raffinosus TCCC11660 was purified 32.3-fold with a recovery rate of 8.3%, using ultrafiltration and ammonium sulfate precipitation, followed by ion-exchange and size-exclusion chromatography. The apparent molecular weight of purified GAD, as determined by SDS-PAGE and size-exclusion chromatography was 55 and 110 kDa, respectively, suggesting that GAD exists as a dimer of identical subunits in solution. In the best sodium citrate buffer, metal ions of Mo(6+) and Mg(2+) had positive effects, while Cu(2+), Fe(2+), Zn(2+) and Co(2+) showed significant adverse effects on enzyme activity. The optimum pH and temperature of GAD were determined to be 4.6 and 45 °C, while the K m and V max values for the sole L-glutamate substrate were 5.26 and 3.45 μmol L(-1) min(-1), respectively.

Concepts: Ammonia, Enzyme, Chemistry, Water purification, PH, Citrate, Polyatomic ion, Sodium citrate