Asymmetric Hydrogenation of 4-Hydroxy-6-methyl-2-pyrone: Role of Acid–Base Interactions in the Mechanism of Enantiodifferentiation

2001 ◽  
Vol 200 (1) ◽  
pp. 171-180 ◽  
Author(s):  
W.-R Huck ◽  
T Bürgi ◽  
T Mallat ◽  
A Baiker
Keyword(s):  
Asymmetric Hydrogenation ◽  
Acid Base

Ethanol conversion over Ga2O3-ZrO2 solid solution: empirical evidences of the reaction pathway, the surface acid–base property, and role of isolated gallium ion

2021 ◽  
Author(s):  
Takashi Yamamoto ◽  
Akihito Kurimoto ◽  
Riona Sato ◽  
Shoki Katada ◽  
Hirotaka Mine ◽  
...  
Keyword(s):  
Solid Solution ◽  
Reaction Pathway ◽  
Ethanol Conversion ◽  
Acid Base ◽  
Base Property ◽  
Temperature Range ◽  
Acid Base Property

Ethanol conversion by Ga2O3-ZrO2 solid solution was examined in the temperature range 573–773 K, and acetone/isobutene formation was confirmed under cofeeding of H2O vapor. The reaction pathway was empirically investigated...

ROLE OF PARATHYROID HORMONE IN ACID-BASE HOMŒOSTASIS

The Lancet ◽  
1970 ◽  
Vol 296 (7687) ◽  
pp. 1363 ◽  
Author(s):  
UrielS. Barzel
Keyword(s):  
Parathyroid Hormone ◽  
Acid Base

Role of ion transfer processes in acid-base regulation with temperature changes in fish

1984 ◽  
Vol 246 (4) ◽  
pp. R441-R451 ◽  
Author(s):  
N. Heisler
Keyword(s):  
Ion Transfer ◽  
Bicarbonate Concentration ◽  
Acid Base ◽  
Fish Tissues ◽  
Model Calculations ◽  
Temperature Changes ◽  
Transfer Processes ◽  
Transfer Mechanisms

The contributions of transmembrane and transepithelial ion transfer processes and of nonbicarbonate buffering to the in vivo acid-base regulation have been evaluated. Model calculations were performed utilizing experimental data on transepithelial transfer of ions relevant for the acid-base regulation, the intracellular buffering properties of fish tissues, and the behavior of intracellular and extracellular pH and bicarbonate concentration with changes of temperature. The results of these studies indicate that the changes in the pK values of physiological nonbicarbonate buffers with changes in temperature support the adjustment of pH to lower values with rising temperature; however, transmembrane and transepithelial ion transfer mechanisms determine the acid-base regulation of intracellular and extracellular compartments.

Insight into the role of varied acid-base sites on fast pyrolysis kinetics and mechanism of cellulose

2021 ◽  
Vol 135 ◽  
pp. 140-149
Author(s):  
Chengyu Li ◽  
Jun Zhang ◽  
Jing Gu ◽  
Haoran Yuan ◽  
Yong Chen
Keyword(s):  
Fast Pyrolysis ◽  
Kinetics And Mechanism ◽  
Pyrolysis Kinetics ◽  
Acid Base ◽  
Insight Into

58 Relationship Between Early Laboratory Measures and Neurological Injury in Neonates Undergoing Therapeutic Hypothermia

2021 ◽  
Vol 26 (Supplement_1) ◽  
pp. e39-e41
Author(s):  
Lilian Kebaya ◽  
Mong Tieng Ee ◽  
Michael Miller ◽  
Soume Bhattacharya
Keyword(s):  
Therapeutic Hypothermia ◽  
Roc Curve ◽  
Base Excess ◽  
Curve Analysis ◽  
Neurological Injury ◽  
Acid Base ◽  
Roc Curve Analysis ◽  
Baseline Characteristics ◽  
Laboratory Measures

Abstract Primary Subject area Neonatal-Perinatal Medicine Background Hypoxic-ischemic encephalopathy (HIE) is a major contributor to morbidity and mortality. Therapeutic hypothermia (TH) is the standard of care for neonates with moderate to severe HIE. Brain magnetic resonance imaging (MRI) is the imaging modality of choice for confirmation of HIE, assessment of injury severity, and prognostication. Reliable, inexpensive and widely available laboratory measures for early identification of risk for neurological injury can play a critical role in the optimal management of neonatal HIE, especially in the resource-limited setting. Our study examined whether derangements in early routine laboratory measures (acid-base, haematological, metabolic) were worse in neonates with MRI findings of neurological injury. Objectives Primary objective: To evaluate the role of early laboratory measures in predicting neurological injury as detected by MRI at 72 hours. Secondary objective: To evaluate the role of early laboratory measures in predicting survival to NICU discharge in patients with HIE. Design/Methods This single-centre, retrospective cohort study included neonates ≥ 35 weeks gestation with moderate to severe HIE, who had undergone therapeutic hypothermia. Based on findings of brain MRI completed within 72 hours of life, our cohort was divided into 2 groups: neonates with, and without, evidence of neurological injury consistent with HIE. Baseline characteristics, as well as laboratory measures, were compared between groups, and a receiver operating characteristic (ROC) curve analysis was conducted to determine the cut-off for prediction of neurological injury based on the highest sensitivity and specificity values. Results 104 neonates were analyzed. Baseline characteristics (Table 1) were similar between both groups, except for cord venous pH and base excess (BE), which were significantly lower in the abnormal MRI group (p = 0.02). In bivariate analysis, pH (at 1 h of age, p = 0.027), BE (at 1 h, p = 0.001, and 6 h of age, p = 0.004), ionized calcium (at 6 h of age, p = 0.02), and platelets (at 1 h of age, p = 0.004) were significantly different in neonates with abnormal MRI. In ROC curve analysis, BE at 1 h of life was the best predictor of abnormal MRI (AUC = 0.71, p = 0.002), with a cut-off value of ≤ -14.95, sensitivity of 67% and specificity of 66% (Figure 1). Conclusion Among neonates with HIE undergoing TH, early laboratory measures such as acid-base status, ionized calcium, and platelet count were worse in neonates with abnormal MRI, in comparison to neonates with normal MRI. Base excess at 1 h of life is a good predictor of abnormal MRI. Future prospective studies to validate these findings are needed

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