A Simple Method of Calculating Dissociation Constants of Carboxylic Acids and Phenols in Various Solvents

1979 ◽  
Vol 32 (11) ◽  
pp. 2561 ◽  
Author(s):  
B Poh
Keyword(s):  
Carboxylic Acids ◽  
Dissociation Constants ◽  
P Value ◽  
Hammett Equation ◽  
Simple Method ◽  
P Values ◽  
Related Series

The Hammett equation correlating the dissociation constants (K for the substituted acid and K0 for the unsubstituted acid) of members of a closely related series of acids is given by log(K/K0) = pσ. Previously, it has been shown that the p values in other solvents can be calculated from the p value in water. In this work it is shown that the pK0 values in other solvents can also be calculated from the pK0 value in water. Therefore, we can now calculate the pK values in various solvents.

Solvent Effect on the Hammett Reaction Constant of Substituted Benzoic Acids

1993 ◽  
Vol 46 (1) ◽  
pp. 31 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
P Values ◽  
Reaction Constant ◽  
Substituted Benzoic Acids ◽  
Reaction Constants ◽  
Solvent Acidity

Potentiometric titration has been used to measure dissociation constants of 13 monosubstituted benzoic acids in nitromethane, benzonitrile , acetonitrile , propylene carbonate, acetone, N,N-dimethylformamide, dimethyl sulfoxide, methanol and formamide. The reaction constants of the Hammett equation were found to depend on the solvent acidity and basicity expressed by the α and β parameters of Kamlet and Taft. The p values determined earlier in water and ethanol also obey this rule.

Solvent Effect on the Dissociation Constants of Aliphatic Carboxylic Acids

1991 ◽  
Vol 44 (8) ◽  
pp. 1077 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
General Formula ◽  
Carboxylic Acids ◽  
Potentiometric Titration ◽  
Dissociation Constants ◽  
Solvent Polarity ◽  
P Values ◽  
Reaction Constants ◽  
Aliphatic Carboxylic Acids

Dissociation constants of 10 aliphatic carboxylic acids, of general formula R-COOH, were measured by potentiometric titration in acetonitrile, propylene carbonate, acetone, N,N- dimethylformamide and dimethyl sulfoxide. The p* reaction constants of the Taft equation were found to depend on the solvent polarity, whereas the influence of the Lewis basicity and acidity is negligible. The p* values determined earlier in water, methanol and nitromethane also fulfil this rule.

scholarly journals Effect of remote ischemic post conditioning on kidney function in STEMI patients undergoing primary percutaneous coronary intervention

2021 ◽  
Vol 10 (Supplement_1) ◽  
Author(s):  
D Arara ◽  
M Fadil ◽  
Y Karani ◽  
RD Nindrea
Keyword(s):  
Myocardial Infarction ◽  
Percutaneous Coronary Intervention ◽  
Kidney Function ◽  
Primary Percutaneous Coronary Intervention ◽  
Coronary Intervention ◽  
Control Group ◽  
P Value ◽  
Baseline Characteristic ◽  
Simple Method ◽  
Percutaneous Coronary

Abstract Funding Acknowledgements Type of funding sources: None. Background Primary percutaneous coronary intervention (PPCI) is a treatment of choice in ST elevation myocardial infarction patients (STEMI). However, this approach could affect the kidney function due to iodinated contrast exposure to the patient. Remote ischemic post conditioning (RIPostC) is a non-invasive and simple method that not only has cardioprotective but also renoprotective effect for kidney function. Purpose The aim of this study was to investigate the effect of RIPostC to kidney function in STEMI patients undergoing PPCI. Methods This study uses pre and post-test only with control group design with experimental research designs. Data was taken at an Indonesian Heart Center from June 2019 until March 2020, there were 66 patients with ST-segment elevation myocardial infarction (STEMI) being performed RIPostC procedure with intermittent ischaemia and reperfusion applied to the arm through five cycles of 5-min inflation and 5-min deflation of an automated cuff device after crossing wire. Creatinine and eGFR were measured pre and 48 hours post PPCI. Kidney function were determined by eGFR post PPCI, ΔeGFR (pre and 48 hours post PPCI), creatinine post PPCI and Δcreatinine (pre and 48 hours post PPCI). Bivariate analysis was performed to determine the effect RIPostC to kidney function using the Chi-square test.  Result A total of 66 patients who underwent the PPCI procedure were divided into two groups RIPostC (n = 33) and without RIPostC (n = 33). The baseline characteristic in both of group was similar. We found that there were no differences of eGFR (70,46 ± 23,06 vs 65,88 ± 23,36, p = 0,424), ΔeGFR (0 [-34,68 - 37,32] vs 0 [-121,53 - 29,70], p value= 0,406), creatinine (1,00 [0,70 - 4,60] vs 1,20 [0,60-4,10], p value= 0,633) and Δcreatinine (0 [-1,20-1,10] vs 0 [-0,50-0,90], p value= 0,390) RIPostC group had a lower CI-AKI incident if we compare with the non RIPostC (15,2% vs 42,4%, p < 0,05). Conclusion Remote ischaemic conditioning does not significantly improve kidney function (eGFR, ΔeGFR, creatinine and Δcreatinine) in patients with STEMI undergoing PPCI The differences of kidney functionVariableRIPostCControlp valueeGFR post PPCI (ml/min/1,73 m2), mean70,46 ± 23,0665,88 ± 23,360,424aΔeGFR(ml/min/1,73 m2), median0 [-34,68 - 37,32]0 [-121,53 - 29,70]0,406bCreatinine post PPCI (mg/dL), median1,00 [0,70 - 4,60]1,20 [0,60-4,10]0,633bΔcreatinine (mg/dL), median0 [-1,20-1,10]0 [-0,50-0,90]0,390ba = Independent sample T testb = mann whitney testAbstract Figure. ΔeGFR and Δcreatinine pre and post PPCI

scholarly journals SAT0210 FACTORS ASSOCIATED WITH TIME TO SEVERE LUPUS NEPHRITIS IN A COHORT OF COLOMBIAN PATIENTS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1048.2-1048
Author(s):  
S. Herrera ◽  
J. C. Diaz-Coronado ◽  
D. Rojas-Gualdrón ◽  
L. Betancur-Vasquez ◽  
D. Gonzalez-Hurtado ◽  
...  
Keyword(s):  
Lupus Nephritis ◽  
Renal Involvement ◽  
Classification Criteria ◽  
P Value ◽  
Systemic Lupus ◽  
P Values ◽  
Interval Censored ◽  
Severe Lupus Nephritis ◽  
Age And Sex

Background:Systemic lupus erythematosus (SLE) clinical manifestations, and their severity, vary according to age, ethnicity and socioeconomic status. Both Hispanic and Afro-Americans have a higher incidence and more sever presentation when compared to Caucasian patients with SLEObjectives:To analyze clinical and immunological characteristics associated with time to severe renal involvement in patients with Systemic Lupus Erythematous in a Colombian cohort followed for one year, between January 2015 and December 2018Methods:Retrospective follow-up study based in clinical records. Patients with SLE diagnosis that fulfilled either 1987 American College of Rheumatology Classification Criteria for SLE or 2011 Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE. We included patients with diagnosis of lupus nephritis according to Wallace and Dubois criteria. Patients who did not have at least two follow-up measurements or had a cause of nephritis other than lupus were excluded. The main outcome was defined as time from diagnosis to sever renal involvement defined as creatinine clearance ≤50 ml/min, 24-hour proteinuria ≥3.5 grams o end stage renal disease.We analyzed clinical and immunological characteristics. Descriptive statistical analyses of participant data during the first evaluation are reported as frequencies and percentages for categorical variables, and as medians and interquartile ranges (IQR) for quantitative variables. Age and sex adjusted survival functions and Hazard ratios (HR) with 95% confidence intervals and p-values were estimated using parametric Weibull models por interval-censored data. P values < 0.05 were considered statistically significantResults:548 patients were analyzed: 67 were left-censored as they presented renal involvement at entry, 6 were interval censored as outcome occurred between study visits, and 475 were right-censored as involvement was not registered during follow-up. 529 (96.5%) patients were female, median age at entry was 46 (IQR = 23) and median age to diagnosis was 29.5 (IQR = 20.6). 67% were mestizo, 13% Caucasian and 0.3% Afro-Colombian. Age and sex adjusted variables associated with time to severe lupus nephritis were high blood pressure HR = 3.5 (95%CI 2.2-5.6; p-value <0.001) and Anti-RO (per unit increase) HR = 1.002 (95%CI 1.001-1.004; p-value = 0.04). Figure 1 shows age and sex adjusted survival function.Conclusion:In our cohort the appearance of severe lupus nephritis occurs in less than 15% of patients at 10 years. Both high blood pressure and elevated anti-Ro titers were associated with a higher rate of onset in the presentation of severe lupus nephritis, as seen in some polymorphs of anti Ro.References:Disclosure of Interests:Sebastian Herrera Speakers bureau: academic conference, Juan camilo Diaz-Coronado: None declared, Diego Rojas-Gualdrón: None declared, Laura Betancur-Vasquez: None declared, Daniel Gonzalez-Hurtado: None declared, Juanita Gonzalez-Arango: None declared, laura Uribe-Arango: None declared, Maria Fernanda Saavedra Chacón: None declared, Jorge Lacouture-Fierro: None declared, Santiago Monsalve: None declared, Sebastian Guerra-Zarama: None declared, Juan david Lopez: None declared, Juan david Serna: None declared, Julian Barbosa: None declared, Ana Sierra: None declared, Deicy Hernandez-Parra: None declared, Ricardo Pineda.Tamayo: None declared

Iron-Catalyzed Domino Decarboxylation-Oxidation of ,-Unsaturated Carboxylic Acids Enabled Aldehyde C−H Methylation

2021 ◽  
Author(s):  
Pei-Xue Gong ◽  
Fangning Xu ◽  
Lu Cheng ◽  
Xu Gong ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Methyl Ketones ◽  
Simple Method ◽  
Unsaturated Carboxylic Acids

A practical and general iron-catalyzed domino decarboxylation-oxidation of ,-unsaturated carboxylic acids enabled aldehyde C−H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses...

NO EVIDENCE, OR NOT ENOUGH EVIDENCE?

PEDIATRICS ◽  
1996 ◽  
Vol 98 (6) ◽  
pp. A22-A22
Author(s):  
Student
Keyword(s):  
Confidence Intervals ◽  
P Value ◽  
P Values ◽  
Considerable Uncertainty ◽  
Absence Of Evidence

When we are told that "there's no evidence that A causes B," we should first ask whether absence of evidence means simply that there is no information at all. If there are data, we should look for quantification of the association rather than just a P value. Where risks are small, P values may well mislead: confidence intervals are likely to be wide, indicating considerable uncertainty.

Abstract MP11: Circulating Plasma Biomarkers Associated With Brain Arteriovenous Malformations

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Sarah E Wetzel-Strong ◽  
Shantel M Weinsheimer ◽  
Jeffrey Nelson ◽  
Ludmila Pawlikowska ◽  
Dewi Clark ◽  
...  
Keyword(s):  
Multiple Testing ◽  
Statistical Significance ◽  
Protein Profiling ◽  
P Value ◽  
P Values ◽  
Plasma Biomarkers ◽  
Standard Curve ◽  
Disease States ◽  
Heparin Plasma ◽  
Circulating Levels

Objective: Circulating plasma protein profiling may aid in the identification of cerebrovascular disease signatures. This study aimed to identify circulating angiogenic and inflammatory biomarkers that may serve as biomarkers to differentiate sporadic brain arteriovenous malformation (bAVM) patients from other conditions with brain AVMs, including hereditary hemorrhagic telangiectasia (HHT) patients. Methods: The Quantibody Human Angiogenesis Array 1000 (Raybiotech) is an ELISA multiplex panel that was used to assess the levels of 60 proteins related to angiogenesis and inflammation in heparin plasma samples from 13 sporadic unruptured bAVM patients (69% male, mean age 51 years) and 37 patients with HHT (40% male, mean age 47 years, n=19 (51%) with bAVM). The Quantibody Q-Analyzer tool was used to calculate biomarker concentrations based on the standard curve for each marker and log-transformed marker levels were evaluated for associations between disease states using a multivariable interval regression model adjusted for age, sex, ethnicity and collection site. Statistical significance was based on Bonferroni correction for multiple testing of 60 biomarkers (P< 8.3x10 - 4 ). Results: Circulating levels of two plasma proteins differed significantly between sporadic bAVM and HHT patients: PDGF-BB (P=2.6x10 -4 , PI= 3.37, 95% CI:1.76-6.46) and CCL5 (P=6.0x10 -6 , PI=3.50, 95% CI=2.04-6.03). When considering markers with a nominal p-value of less than 0.01, MMP1 and angiostatin levels also differed between patients with sporadic bAVM and HHT. Markers with nominal p-values less than 0.05 when comparing sporadic brain AVM and HHT patients also included angiostatin, IL2, VEGF, GRO, CXCL16, ITAC, and TGFB3. Among HHT patients, the circulating levels of UPAR and IL6 were elevated in patients with documented bAVMs when considering markers with nominal p-values less than 0.05. Conclusions: This study identified differential expression of two promising plasma biomarkers that differentiate sporadic bAVMs from patients with HHT. Furthermore, this study allowed us to evaluate markers that are associated with the presence of bAVMs in HHT patients, which may offer insight into mechanisms underlying bAVM pathophysiology.

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