The precise neural mechanisms underlying transitions between consciousness and anesthetic-induced unconsciousness remain unclear. Here, we studied intracortical neuronal dynamics leading to ...propofol-induced unconsciousness by recording single-neuron activity and local field potentials directly in the functionally interconnecting somatosensory (S1) and frontal ventral premotor (PMv) network during a gradual behavioral transition from full alertness to loss of consciousness (LOC) and on through a deeper anesthetic level. Macaque monkeys were trained for a behavioral task designed to determine the trial-by-trial alertness and neuronal response to tactile and auditory stimulation. We show that disruption of coherent beta oscillations between S1 and PMv preceded, but did not coincide with, the LOC. LOC appeared to correspond to pronounced but brief gamma-/high-beta-band oscillations (lasting ∼3 min) in PMv, followed by a gamma peak in S1. We also demonstrate that the slow oscillations appeared after LOC in S1 and then in PMv after a delay, together suggesting that neuronal dynamics are very different across S1 versus PMv during LOC. Finally, neurons in both S1 and PMv transition from responding to bimodal (tactile and auditory) stimulation before LOC to only tactile modality during unconsciousness, consistent with an inhibition of multisensory integration in this network. Our results show that propofol-induced LOC is accompanied by spatiotemporally distinct oscillatory neuronal dynamics across the somatosensory and premotor network and suggest that a transitional state from wakefulness to unconsciousness is not a continuous process, but rather a series of discrete neural changes.
How information is processed by the brain during awake and anesthetized states and, crucially, during the transition is not clearly understood. We demonstrate that neuronal dynamics are very different within an interconnecting cortical network (primary somatosensory and frontal premotor area) during the loss of consciousness (LOC) induced by propofol in nonhuman primates. Coherent beta oscillations between these regions are disrupted before LOC. Pronounced but brief gamma-band oscillations appear to correspond to LOC. In addition, neurons in both of these cortices transition from responding to both tactile and auditory stimulation before LOC to only tactile modality during unconsciousness. We demonstrate that propofol-induced LOC is accompanied by spatiotemporally distinctive neuronal dynamics in this network with concurrent changes in multisensory processing.
Donor and recipient factors are closely associated with graft survival after orthotopic liver transplantation (OLT). This study was performed to analyze clinical characteristics of recipients and ...donors, which affect 30-day graft loss after OLT.
One hundred eighty-six livers from heart-beating donors were accepted between May 1997 and June 1998 at the University of Pittsburgh Medical Center. Donor variables that were analyzed included age, sex, cold ischemia time (CIT), warm ischemia time (WIT), imported versus local procurement, cardiopulmonary arrest, serum sodium level, and dopamine dose. The recipient characteristics included native liver disease and UNOS status. Two-sided Fisher exact test and stepwise logistic regression were used for univariate and multivariate analyses.
P-values < .05 were considered statistically significant.
Twenty-eight grafts (15.1%) were lost within 30 days of OLT. The following factors were found to adversely affect graft survival: donor sodium >155 mEq/L (
P = .002); CIT >12 hours (
P = .002); WIT >45 minutes (
P = .002); and imported liver graft (
P = .048). Logistic regression revealed that donor sodium (odds ratio, 3.03; 95% CI, 1.05 to 8.74), CIT (OR 1.20; 95% CI 1.05 to 1.38), WIT (OR 1.06; 95% CI 1.01 to 1.09) were independent predictors of early graft loss.
Donor hypernatremia as well as warm and cold ischemia times independently affect graft outcomes in the early postoperative period after OLT. Avoidance of long preservation and correction of donor sodium level are recommended to optimize results and survival in OLT.
We report synthesis of perovskite-type boride CeRh3Bx using the arc melting method. The samples are characterized by powder X-ray diffraction which shows that the crystal structure of CeRh3Bx belongs ...to the cubic system (space group: Pm3m) in the range of 0 < x < or = 1. Furthermore, CeRh3 (x=0) has the ordered AuCu3-type structure (space group: Pm3m). As a result, CeRh3Bx exists in a wide range of nonstoichiometric boron concentration 0 < or = x < or = 1 with the space group Pm3m. The lattice parameter, a, changes almost linearly with x, varying from 0.4015(1) nm (x=0) to 0.4180(1) nm (x= 1.0). The micro-Vickers hardness of the CeRh3Bx for x=0 (0at.%B), 0.210 (5 at.%B), 0.444 (10at.%B), 0.706 (15 at.%B) and 1.0 (20at.%B) are 2.0plus/minus 0.1, 4.3 plus/minus 0.2, 1.8 plus/minus 0.2, 5.5 plus/minus 0.1 and 6.5 plus/minus 0.2 GPa, respectively. Thermo-gravimetric analysis was done to study the oxidation resistance of the samples in air. It reveals that oxidation begins at 502 and 513Kfor x=0 and 1.0, respectively. A mixed phase of CeO2 + Rh is identified as an oxidized product for all samples.
Prolonged cold ischemia time (CIT) during graft preservation and warm ischemia time (WIT)
during rewarming time have been reported to cause postoperative graft dysfunction after
orthotopic liver ...transplantation (OLT). However, the effects of both CIT and WIT in combination on
patient and graft survivals are not yet defined. The aim of this study was to determine
whether simultaneously prolonged CIT and WIT were associated with early graft outcomes after
clinical OLT. For analysis of liver graft survival within 90 days of OLT and postoperative graft
function, 186 consecutive OLT cases were
divided into four groups as follows: group A, CIT < 12 hours and WIT < 45 minutes; group B, CIT > 12
hours and WIT < 45 minutes; group C, CIT < 12 hours and WIT > 45 minutes; and group D, CIT > 12 hours
and WIT > 45 minutes.
The graft loss rates were 5.4% in group A, 9.8% in group B, 11.1% in
group C, and 42.9% in group D. The mean highest aspartate aminotransferase (AST) value
after OLT in group D (3352.3 ± 569.4 U/L) was significantly greater than those in groups A
(1411.7 ± 169.2 U/L) and B (1931.3 ± 362.6 U/L). The simultaneously prolonged cold and
warm ischemia times significantly caused hepatic allograft injury and failure, suggesting some
cumulative effects of CIT and WIT on postoperative graft function.
Perovskite-type RRh3 B and RRh3 C (R = Y, Sc) form a continuous solid solution, RRh3BxC1-x, in the range of 0 < or = x < or = 1 with cubic structure (space group: Pm3m, Z= 1). The values of the ...microhardness of YRh3BxC1_x for x=0, 0.25, 0.50, 0.75 and 1.00 are investigated as 4.4-0.1, 4.9 -0A, 5.5 - 0.2, 6.4 - 0.2 and 7.5 - 0.15 GPa, respectively. On the other hand, the values of the microhardness of ScRh3BxCI x for x=0, 0.25, 0.50, 0.75 and 1.00 are 4.5 - 0.2, 6.1 f 0.2, 7.4 - 0.2, 8.9 - 0.2 and 9.6 - 0.1 GPa, respectively. Thus, the microhardness of RRh3BxC1-x continuously becomes larger with increasing boron content. The oxidation onset temperatures of YRh3BxC1_x for x=0, 0.25, 0.50, 0.75 and 1.00 are 604, 631, 655, 687 and 978K, respectively. On the other hand, the oxidation onset temperatures of ScRh3BxC1-x for x=0, 0.25, 0.50, 0.75 and 1.00 are 674, 675, 695, 725 and 753 K, respectively. Thermogravimetric analysis of the phase indicates that the oxidation onset temperature also increases with boron content. Thus, it appears that both mechanical strength and chemical stability of the RRh3BxC1 x phase essentially depend on its boron content. Ab initio calculations have been performed to obtain the equilibrium lattice constants and the bulk moduli. The calculated lattice constants are in excellent agreement with experimental results.
Rare earth ternary borides, RRh3Bx (R = La, Gd, Lu and Sc) have been synthesized by arc melting method. Borides RRh3B (R = La, Gd, Lu and Sc) have perovskite-type cubic structure: space group Pm3m; ...Z=1. The lattice parameters a of the stoichiometric RRh3B for R = La, Gd, Lu and Sc are 0.4251(1), 0.4183(1), 0.4126(1) and 0.4080(1) nm, respectively. LaRh3B, does not have boron-nonstoichiometry as x = 0. In GdRh3Bx and LuRh3Bx, boron- nonstoichiometry ranges between 0.55 < or = x < or = 1 and 0.30 < or = x < or = 1, respectively. The boron-nonstoichiometry range is the widest, 0 < or = x S 1, for R = Sc. Boron-nonstoichiometry increases with decreasing atomic radius of R. The microhardness of the stoichiometric RRh3B for R = La, Gd, Lu and Sc is 4.2 - 0.1, 6.8 f 0.1, 7.7 - 0.5 and 9.9 - 0.1 GPa, respectively. As a result, microhardness increases with decreasing atomic size of R in RRh3B; R is positioned at the eight corners of the cube in the perovskite-type structure. Thus, hardness is strongly dependent on R element. The hardness changes almost linearly with boron concentration x for R = Gd and Lu in RRh3Bx, while no linear dependency is found for R = Sc. Ab initio calculations have been performed to obtain the equilibrium lattice constants and the bulk moduli. The calculated lattice constants are in excellent agreement with experimental results.
This study was performed to investigate whether intraoperative changes in blood lactate levels after hepatic allograft reperfusion reflect initial graft function in living donor liver transplantation ...(LDLT).
From 1994 to 2003, 15 of LDLT cases were divided into two groups based on the intraoperative blood lactate levels. Group A consisted of seven recipients whose new liver grafts started to consume lactate immediately after portal perfusion. Group B consisted of the remaining eight recipients whose intraoperative blood lactate values showed no change or an elevation for 2 hours after graft revascularization.
All Group A patients survived, whereas three out of eight patients in Group B died of infection and portal vein thrombosis within 3 months after LDLT. There was no significant difference in preoperative donor and recipient laboratory data. The recipient age and body size in Group B were significantly higher than those in Group A, indicating that Group B consisted of small-for-size liver transplant cases. Serum total bilirubin concentrations in Group B were significantly higher than Group A from postoperative day 5 to 23, whereas postoperative liver enzyme levels and prothrombin time were similar between the two groups.
The change in intraoperative blood lactate after hepatic allograft reperfusion served as an accurate predictor of initial graft function which was associated with graft size in human LDLT.
ABSTRACTMartensitic stainless steels (SS) have been used widely for oil-country tubular goods (OCTG) because of their high strength and excellent corrosion resistance in carbon dioxide (CO2) gas ...wells. Cr-rich precipitates form after tempering heat treatments of martensitic SS. These precipitates can affect the corrosion resistance of martensitic SS in environments simulating CO2 gas wells because Cr is considered to be an important element for improving corrosion resistance. The effects of chemical composition and tempering heat treatments on corrosion rates and pitting potentials were investigated to clarify the effect of precipitates on corrosion resistance of martensitic SS in environments simulating CO2 gas wells. The general corrosion index (GCI = Cr 12 C + 0.77 Ni + 10 N mass %) was confirmed as a good index for estimating corrosion rates of martensitic SS in environments simulating CO2 gas wells. The term C coefficient/Cr coefficient (12), was defined as the amount of Cr as carbide precipitates (M23C6) in martensitic SS from the analysis of precipitates. The term N coefficient/Cr coefficient was positive because soluble N was effective in improving corrosion resistance, as demonstrated by surface analysis. From electrochemical analysis, the anode reaction of martensitic SS was controlled by a high GCI. Pitting potentials in environments simulating CO2 gas wells depended on Cr 12 CINTRODUCTIONMartensitic stainless steels (SS) have been used widely for oil-country tubular goods (OCTG) because of their high strength and excellent corrosion resistance in carbon dioxide (CO2) gas wells. Type 420 (UNS S42000, 13% Cr-0.2% C),(1) one of the most popular martensitic SS for OCTG, was reported to be applicable in CO2 gas wells with temperatures from 120°C to 150°C.1-3 The temperature of CO2 gas wells has increased with deeper wells being drilled. Usually, 22% Cr ferritic/austenitic duplex SS are used in CO2 wells with temperatures from 120°C to 150°C. Recently, much attention has been paid to modified martensitic SS for OCTG.3-9 Low-C, high-Ni steels (13% Cr-5% Ni-2% Mo martensitic SS)8 and mediumC, medium-Ni steels (15% Cr martensitic SS, with 0.12% C, 0.5% Mo, 1.5% Ni, and 0.07% N)9 have been developed for CO2 gas wells as a partial substitute for 22% Cr duplex SS. Corrosion resistance of
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