Triality, periodicity and stability of SO(8) gauged supergravity

While electromagnetic duality is a symmetry of many supergravity theories, this is not the case for the N = 8 gauged theory. It was recently shown that this rotation leads to a one-parameter family of SO(8) supergravities. It is an open question what the period of this parameter is. This issue is investigated in the SO(4) invariant sectors of the theory. We classify such critical points and find a novel branch of non-supersymmetric and unstable solutions, whose embedding is related via triality to the two known ones. Secondly, we show that the three branches of solutions lead to a π/4 periodicity of the vacuum structure. The general interrelations between triality and periodicity are discussed. Finally, we comment on the connection to other gauge groups as well as the possibility to achieve (non-)perturbative stability around AdS/Mkw/dS transitions.

Impact of changes in haematocrit level and platelet count on thromboelastometry parameters

INTRODUCTION To what extent haematocrit levels (Hct) and platelet counts (PLT) influence the measurement of parameters of thromboelastometry when assessed with the ROTEM® device is unclear. We investigated to what extent thromboelastometry measurements depend on Hct and PLT. MATERIALS AND METHODS Whole blood samples were taken for in-vitro preparations of mixtures with three different levels of PLT and a varying Hct. Maximum clot firmness (MCF), clotting time (CT), clot formation time (CFT) and alpha angle (α) for INTEM, EXTEM, FIBTEM and APTEM was recorded. RESULTS Measurements depended substantially on Hct and PLT. MCF readings were systematically lower with increasing Hct (0.2 vs. 0.4: -7.8 (-8.3 to -7.2); p<0.001, 0.2 vs. 0.55: -14.5 (-17.3 to -14.3); p<0.001) but higher with increasing PLT (50 vs. 125×10(9)/l: 8.2 (4.2 to 12.3); p=0.005, 50 vs. 250×10(9)/l: 12.0 (7.2 to 16.8); p=0.002). CT readings were systematically higher with increasing Hct (0.2 vs. 0.4: 9.2 (6.2 to 12.1); p=0.001, 0.2 vs. 0.55: 38.2 (21.5 to 54.9); p=0.003) while increasing PLT had no influence. CFT readings were also systematically higher with increasing Hct (0.2 vs. 0.4: 83.8 (40.2 to 127.6); p=0.006, 0.2 vs. 0.55: 226.2 (110.7 to 341.7); p=0.006) but systematically lower with increasing PLT (50 vs. 125×10(9)/l: -144.0 (-272.3 to -15.6); p=0.036, 50 vs. 250×10(9)/l: -189.2 (-330.4 to -48.0); p=0.02); readings of the alpha angle showed a similar pattern. CONCLUSIONS Our results suggest that readings of thromboelastometry parameters need to be adjusted by Hct and PLT to avoid potential confounding and miss-interpretations in clinical practice.

Comparison of the in vitro effects of saline, hypertonic hydroxyethyl starch, hypertonic saline, and two forms of hydroxyethyl starch on whole blood coagulation and platelet function in dogs.

OBJECTIVE To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs. DESIGN In vitro experimental study. SETTING Veterinary teaching hospital. ANIMALS Twenty-one adult dogs. INTERVENTIONS Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3. MEASUREMENTS AND MAIN RESULTS Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES. CONCLUSIONS Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions.

Generalised integrable λ- and η-deformations and their relation

We construct two-parameter families of integrable λ -deformations of two-dimensional field theories. These interpolate between a CFT (a WZW/gauged WZW model) and the non-Abelian T-dual of a principal chiral model on a group/symmetric coset space. In examples based on the SU(2) WZW model and the SU(2)/U(1) exact coset CFT, we show that these deformations are related to bi-Yang–Baxter generalisations of η-deformations via Poisson–Lie T-duality and analytic continuation. We illustrate the quantum behaviour of our models under RG flow. As a byproduct we demonstrate that the bi-Yang–Baxter σ-model for a general group is one-loop renormalisable.

In vitro effects of 3 % hypertonic saline and 20 % mannitol on canine whole blood coagulation and platelet function.

BACKGROUND: Hyperosmolar therapy, using either mannitol or hypertonic saline (HTS), is considered the treatment of choice for intracranial hypertension. However, hyperosmolar agents may impair coagulation and platelet function, limiting their use in patients at risk for hemorrhage. Despite this, studies evaluating the effects of mannitol compared to other hyperosmolar agents in dogs are largely lacking. The aim of this study was to compare the in vitro effects on global hemostasis and platelet function of 20 % mannitol and 3 % HTS on canine blood. METHODS: Citrated whole blood from 15 healthy dogs was diluted with 0.9 % saline, 20 % mannitol and 3 % HTS in ratios of 1:16 and 1:8. Rotational thromboelastometry (ROTEM) was used to assess clotting time (CT), clot formation time (CFT) and maximal clot firmness (MCF) following extrinsic activation (Ex-tem) and after platelet inhibition (Fib-tem). A platelet function analyzer (PFA-100) was used to assess closure time (CtPFA). RESULTS: No significant differences were observed between untreated whole blood and samples diluted with saline. Samples diluted with both mannitol and HTS were hypocoagulable compared to untreated whole blood samples. At a dilution of 1:16, no significant differences were found between any measured parameter in samples diluted with saline compared to mannitol or HTS. At a 1:8 dilution, CtPFA was prolonged in samples diluted with mannitol and HTS compared to saline, and CtPFA was prolonged more with mannitol than HTS. Ex-tem CT was increased at a 1:8 dilution with mannitol compared to HTS. Ex-tem CFT was prolonged at a 1:8 dilution with both agents compared to saline, and was prolonged more with mannitol than HTS. Ex-tem MCF was reduced at a 1:8 dilution with both agents compared to saline. DISCUSSION AND CONCLUSIONS: Data in this study indicate that both mannitol and HTS affect canine platelet function and whole blood coagulation in vitro in a dose-dependent fashion. The most pronounced effects were observed after high dilutions with mannitol, which impaired platelet aggregation, clot formation time, clot strength, and fibrin formation significantly more than HTS. Further in vivo studies are necessary before recommendations can be made