bluuebunny/crossref_metadata_2025 huggingface dataset:
Apparent Dissociation Constant of Phenol Red as Determined by Spectrophotometry and by Visual Colorimetry
Authors: Sendroy Julius , Rodkey F Lee
Published: January 2020

The apparent pK' of phenol red was determined in buffered NaCl solutions of known composition at 25° and 37°, by both spectrophotometric and visual colorimetric measurement of the concentration ratios of the alkaline to acid form of the indicator. A small but statistically significant difference was obtained by the two procedures. The pK' values obtained in 0.15M NaCl spectrophotometrically (7.67 at 25° and 7.57 at 37°) were approximately 0.03 unit lower than those obtained colorimetrically. Measurements made as a function of NaCl concentration at 25° were in accord with the Debye-Hückel theory. Small variation was observed between solutions buffered with phosphate or tris at the higher NaCl concentrations. The results indicate that in addition to ionic strength and temperature, variations in method of measurement and in the source of the preparation are important factors in the determination and use of pK' values for phenol red. Attention is called to the pertinence of these results to the measurement of blood pH by colorimetric and spectrophotometric methods.
A Rapid Spot Test for the Determination of Cystinuria and Aminoaciduria
Authors: Fischl J , Sason I , Segal Sara
Published: January 2020

A simple test for the determination of cystinuria and of aminoaciduria is described. The basis of the test is the color reaction between nitroprusside and thiol groups. The reagent is a dry mixture to which the urine samples are applied. The ease of peformance of the test makes it ideal for use as a screening procedure. The reaction is nonspecific, and positive tests require further investigation by more elaborate laboratory procedures.
A Comparison of Methods for Determining Catechol Amines and 3-Methoxy-4-hydroxymandelic Acid in Urine
Authors: Mahler D J , Humoller F L
Published: January 2020

The chemical laboratory measures used in the diagnosis of pheochromocytoma have been evaluated. Bio-assay, fluorometric, and spectrophotometric methods were used. Urinary VMA and catechol amine values found for normal and hypertensive groups compared well with those reported by other investigators. The quantitative measurement of urinary VMA by means of a proposed ethyl acetate extraction proved quite reliable.
An Ultramicro Method for the Estimation of Plasma Cholesterol
Authors: Duboff G S , Stevenson W W
Published: January 2020

A procedure is outlined for the ultramicro determination of total cholesterol that gives results in excellent agreement with classic methods. The determination requires 40 µl. of plasma obtained from a finger-tip puncture and special handling of precipitated proteins.

By the use of the described procedure plasma cholesterol levels have been estimated 4 times daily over a period of 8 weeks in young men undergoing rigorous physical training and 3 times daily in women during the menstrual cycle.

A striking fall in total plasma cholesterol was observed in men following physical conditioning in contrast to controls, and a similar decrease was observed in women with normal menstrual cycles in contrast to women with an anovulatory menses.

It is suggested that the total cholesterol decrease in the female coincides with the phase in the menstrual cycle when estrogen activity is maximal and that the lowering of total cholesterol in men, following physical conditioning, may be due to an increased production of endogenous androgens with a consequent increase in conversion of these steroids to estrogens.
Serum Adenosine Deaminase: Methodology and Clinical Applications
Authors: Koehler Leonore Hollander , Benz Edward J
Published: January 2020

Adenosine deaminase activity of serum has been studied to explore its clinical applicability. The results suggest greater usefulness of this parameter for certain disease states of liver and lymph systems than for cancer. The assay, under controlled conditions, was found to be capable of producing precise results.
Assay of Growth Hormone-like Activity in Blood Plasma
Authors: Tweed Devina C , McCullagh E Perry
Published: January 2020

Growth hormone has been shown to increase the uptake of sulfur-35 into tibial epiphyseal cartilage as well as to increase the width of the cartilage plate in linear fashion with increasing dosage. That growth hormone is not alone responsible has been experimentally demonstrated by the increase in both responses effected by injections of human albumin and insulin, and the decrease produced by ACTH.

Tests on human blood plasma indicated the following: (1) The blood specimens of patients with the same clinical syndrome do not always yield similar values when tested by these methods. (2) The blood of hypophysectomized patients can increase both the sulfur uptake and epiphyseal cartilage width. (3) Blood of patients with active acromegaly does not always stimulate the sulfur uptake or increase the cartilage width. (4) In a number of cases in which the sulfur uptake was increased, the tibia test was negative. Conversely, the tibia test occasionally was positive when there was no increase in sulfur uptake. (5) In a few cases in which the tests were repeated on the same patient, the results were not in agreement. (6) In only 7 cases (of 40) was there good correlation between the two methods.

Other growth factors in blood can interfere with the specificity of both methods for the measurement of growth hormone.
The Osmotic Pressure and Chemical Composition of Human Body Fluids
Authors: Hendry Edward B
Published: January 2020

The total osmotic pressure (osmolarity) of each of a series of true body fluids has been measured and compared with that of the corresponding serum. Included were ascitic, cerebrospinal, hydrocele, edema, pericardial, pleural, spermatocele, and synovial fluids. In each case, the fluid was found to have the same osmolarity as that of the corresponding serum within the limits of experimental error. The conclusion has been reached that there is a law of constant osmotic pressure of all true body fluids (as distinct from secretions) and that this law holds whether the subject is biochemically normal or abnormal. Examination of the protein and ionic concentrations of these fluids strongly points to the conclusion that neither colloid osmotic pressure, increased capillary permeability, nor membrane damage can be the primary cause of these abnormal fluid collections. Some profound chemical differences have been demonstrated between the ionic composition of certain of these fluids and that of the corresponding serum. Additional evidence has been presented showing that intraand extracellular osmolarities are identical in the erythrocyte in a wide variety of abnormal cases.
Bilirubin Studies on the Serum of Newborn Infants
Authors: Reiner Miriam , Thomas Jack L
Published: January 2020

Total bilirubin concentration was determined on the sera of a group of newborn infants. Results obtained by a direct spectrophotometric method were compared simultaneously with those of a diazo procedure, using a simple spectrophotometer. The results showed close agreement provided that the sera were unhemolyzed. The effect of hemolysis on both methods is discussed.
A Method for the Fractionation and Quantitative Determination of the 17-Oxosteroids of Urine
Authors: Watson David J , Besch Paige K
Published: January 2020

A method for the quantitative fractionation and estimation of urinary 17-oxosteroids is presented. The method utilizes paper chromatographic technics for separation of the steroids, which are quantitated with the Zimmerman reaction using m-dinitrobenzene. Details of the chromatographic procedure are given, with a comparison of this with other methods in use.
Gas Chromatographic Separations of Drugs and Drug Metabolites
Authors: VandenHeuvel W J A , Haahti E O A , Horning E C
Published: January 2020

Gas chromatographic methods may be used for the separation of many drugs and drug metabolites for purposes of identification or estimation. The most useful technics involve the use of columns with relatively thin films of thermostable liquid phases coated on inert or inactivated supports, and used with high-sensitivity detectors. Classes of compounds which may be studied include barbiturates, quinolines used as antimalarials, and phenothiazines and diphenylamines.
A Micromethod for the Determination of Serum Iron and Serum Iron-Binding Capacity
Authors: Scarlata Robert W , Moore Edward W
Published: January 2020

A reliable method is described for the determination of serum iron and iron-binding capacity in microaliquots of serum, using modifications of the Ramsay methods and the Beckman-Spinco ultramicro analytical system.
Study of a Differential Demasking Technic for Serum Zinc
Authors: Williams Louis A , Cohen Jerry S , Zak Bennie
Published: January 2020

A differential decomplexation technic for the determination of serum zinc in filtrates was studied. It involved the masking of zinc, copper, and iron by the addition of cyanide to a buffered aliquot of an acid filtrate, followed first by the destruction of the excess cyanide and then the cyanide attached to zinc. The release of ionic zinc allowed reaction with the color reagent to take place. Quantitation with internal blanking was thereby accomplished before interference by other cations became possible.
Specific Enzymatic Determination of Glucose in Blood Serum or Plasma by an Automatic Potentiometric Reaction-Rate Method
Authors: Malmstadt H V , Pardue H L
Published: January 2020

A new automatic potentiometric reaction-rate method has been applied to the specific enzymatic measurement of glucose in blood plasma or serum. A new filtering technic is described for removal of precipitated protein. The use of injection pipets to simplify and speed up the reagent-and sample-handling step is described. Glucose is determined in 0.02 ml. of serum or plasma with relative errors within 2%. The average measurement time is about 30 sec.
Determination of Organic Iodine Compounds in Serum
Authors: Pileggi Vincent J , Henry Richard J , Segalove Milton , Hamill George C
Published: January 2020

RI — values of organic iodine compounds which interfere with the determination of serum protein-bound iodine (PBI) and butanol-extractable iodine (BEI) levels were obtained for the solvent system 2-butanol-4% NH4OH (3:1) utilizing descending paper chromatography. The feasibility of employing this system for identification of exogenous organic iodine in patients' sera was investigated. In general, the demonstration of these compounds or their metabolites was achieved only in sera obtained shortly after administration. This was due mainly to sensitivity limitations in the detection of the compounds on paper. Some data on the duration of interference with the PBI and BEI were also obtained for the radiopaque dyes Telepaque, Hypaque, Salipix, and Orabilex.
The Time-Skill-Frequency (TSF) Unit for Reporting Laboratory Work-Load
Authors: Hainline Adrian
Published: January 2020

The concept that the number of tests performed is an accurate measure of the laboratory work-load may be misleading. On the premise that a system based on technician time would be superior, the time-skill-frequency (TSF) unit was devised. The TSF unit is the length of time necessary for an average analyst to perform a single determination, multiplied by factors based on the length of time necessary to do duplicate determinations, the skill involved, and the frequency with which the test is performed in the laboratory. Ideally such units should be calculated for the methods and conditions of each individual laboratory.
Diagnostic Biochemistry and Clinical Medicine: Facts and Fallacies
Authors: Bodansky Oscar
Published: January 2020

In this paper we have attempted to define the relationships between clinical medicine and diagnostic or, as it is more frequently termed, clinical biochemistry. We have indicated first, the role that general biochemistry has played in elucidating mechanisms of disease and in providing the clinician with procedures that aid him in the diagnosis of disease and in the care of the patient. We have illustrated this role by reviewing very briefly some of the recent contributions such as the expanded diagnostic use of serum enzymes; the correlation of subcellular structure in human tissues with function at enzymatic levels; the investigation of enzyme variants; the metabolism of epinephrine and norepinephrine in pheochromocytoma; the metabolism of tryptophan in malignant carcinoid; and enzyme defects in hereditary disease.

We noted the reservations with which the clinician frequently views the specific results that he obtains from the diagnostic biochemistry laboratory and have attempted to analyze the bases for these reservations. In this connection we considered the phenomenon of interlaboratory variability, the nature of the random and the constant errors that may exist within a laboratory, and the measures that the clinical biochemist may take to counteract these errors.

We have tried to indicate the steps the clinician may take in a fuller and more knowledgeable utilization of the data from the diagnostic biochemistry laboratory. These involve a recognition of the efforts and advances that are being made in increasing precision and accuracy within the laboratory and the role that the clinician himself can play in contributing to this precision and accuracy. The phenomenon of intraindividual and interindividual variability of biochemical parameters, and the significance of this phenomenon in diagnosis, are also worthy of the clinicians attention. Finally, the clinician should abjure the concept that a seeming discrepancy between his formulation and laboratory results usually means a laboratory error. Thoughtful review, in cooperation with the biochemist, of such discrepancies are of value both for clinical medicine and clinical biochemistry.
The Renal Aminoacidurias
Authors: Harper Harold A , Doolan Paul D
Published: January 2020

The normal mechanisms whereby the renal tubules handle amino acids are reviewed as a basis for interpretation of the physiologic causes of the renal aminoacidurias. Under normal circumstances, the renal tubules reabsorb in excess of 93% of the amino acids filtered from the plasma. When the filtered load of amino acids is increased, as by intravenous injection of amino acids, there is an increase in both the amounts reabsorbed and those excreted, but the ability of the renal tubule to respond to an increased filtered load of amino acids is so great that a maximum rate of reabsorption has not been found in the human. However, the tubule does exhibit selectivity with respect to the reabsorption of each of the naturally occurring L-amino acids; furthermore, there is a much greater efficiency of reabsorption of the L as compared to the D isomers of the individual amino acids.

The excretion of amino acids is influenced to an important degree by the glomerular filtration rate, as exemplified by studies in pregnant subjects as well as patients with renal disease affecting glomerular filtration.

Several renal aminoacidurias of clinical interest are discussed with special reference to their diagnostic and metabolic significance.
Variation of Protein Content of Urine in a 24-hour Period
Authors: Altman Kenneth A , Stellate Rodney
Published: January 2020

Variation of the protein content in urine of patients known to excrete protein in excessive amounts was studied. Variation in different specimens obtained from the same patient on a particular day and from day to day were studied. A total of 293 urine specimens excreted over a 3- to 6-day period by 25 patients were examined. No particular pattern of protein excretion was observed. The morning specimen was not the specimen with the highest protein content. This could occur at any time during the day. It is suggested that only a 24-hour collection can give a true indication of protein spillage.

A commercial paper strip test was compared with the qualitative sulfosalicylic acid reaction and a quantitative biuret procedure. The strip test is satisfactory for screening purposes except for highly colored urines, in which case the sulfosalicylic acid procedure is recommended.
Detection and Quantitative Determination of Glycine with Pyridine and p-Nitrobenzoyl Chloride
Authors: Umberger Charles J , Fiorese Frank F
Published: January 2020

Glycine in quantities as small as 0.5 µg. can be detected as an orange-red color by a specific reaction with p-nitrobenzoyl chloride and pyridine. The procedure can be used both as a qualitative spot test and as a sensitive quantitative method. In a discussion of the reaction mechanism, it is suggested that the color is due to azlactone formation.
Acrylamide-Gel Electrophoresis of Hemoglobins
Authors: Nakamichi Masumi , Raymond Samuel
Published: January 2020

Details of a technic for analysis of hemoglobin mixtures using acrylamide-gel electrophoresis are presented. The method offers increased speed and reproducibility. Measurements on the unstained gel are made at 525 and at 420 m µ in a procedure affording increased precision of measurements for minor components. The gel is then stained with amidoblack to detect and measure nonhemoglobin components. The major component of normal human adult hemoglobin is separated into two components in this medium. The two components (A1, A3) appear in varying relative amounts depending on the source of the specimen. The normal minor component A2 also appears. After staining the pattern with a protein dye such as amidoblack 10B, additional components appear in the electrophoresis patterns of hemolysates from carefully washed red cells. These components have a constant migration ratio referred to hemoglobin A1 and appear to be nonheme-containing intraerythrocytic proteins.
A Study of the Accuracy and Precision of Clinical Chemistry Determinations in 170 Canadian Laboratories
Authors: Tonks David B
Published: January 2020

Lyophilized samples of two serum pools, prepared commercially, were sent to 200 Canadian clinical chemistry laboratories for estimations of total cholesterol, sodium, chloride, glucose, nonprotein or urea nitrogen, total protein, and inorganic phosphorus. The purpose of this evaluation study was to determine if these laboratories, as a group, were performing satisfactorily, and to help individual laboratories to evaluate their performances and detect gross errors in their results.

Values were reported from 170 laboratories. A summary of the complete data is presented in the form of tables, scatter diagrams, and frequency charts. It was found that there was a lack of accuracy and precision in many laboratories. Over 40% of the 3762 values reported fell outside of the allowable limits of errors and therefore were classified as unacceptable. These results indicated a need for improved performances in many of the participating laboratories.
The Direct Spectrophotometric Determination of Protein in Cerebrospinal Fluid
Authors: Patrick Roman L , Thiers Ralph E
Published: January 2020

A rapid and sensitive direct spectrophotometric method for the determination of cerebrospinal fluid protein which uses as little as 0.1 ml. of sample has been described. The result is not affected by the ratio of albumin to globulin in the sample.

Interfering substances are removed prior to spectrophotometric measurement with an automatic separation chamber employing the principle of gel filtration.

Slight alterations of the procedure described for the measurement of protein enable one to obtain the nonprotein moiety for study or to measure proteins in other biologic fluids.
Rapid Cellulose Acetate Electrophoresis
Authors: Bartlett Raymond C
Published: January 2020

A method is described for the qualitative and quantitative analysis of abnormal hemoglobins including hemoglobin A2. Quantitative values are comparable to those observed with the starch block technic. The analysis is completed within 2 hr. The apparatus is the same as that used for quantitative analysis of serum proteins.
Enzymatic Oxalate Determination in Urine
Authors: Mayer Gerda G , Markow Deborah , Karp Frieda
Published: January 2020

A method depending upon the use of oxalic decarboxylase is described for the determination of oxalic acid in urine. The urinary oxalate excretion of 25 healthy persons measured by this procedure is found to average 20.5 mg. (COOH)2/24 hr. In 70 patients with calculus disease the oxalate titer of the urine was within the normal range.
The Effect of Fatty Acids upon Tumor Cell Respiration and Transplantability
Authors: Katchman Bernard J , Zipf Robert E , Murphy James P F
Published: January 2020

The kinetic effect of palmitate, stearate, oleate, linoleate, and linolenate upon in vitro endogenous respiration of rat chloromyeloid leukemic cells has been investigated.

Inhibition of respiration has been correlated with the ability of fatty acids to cause decreased cell viability and cell count; in the bioassay of fatty acid-treated tumor inocula, the increase in animal life span is correlated to the degree of dilution of the inocula due to cell lysis.

The degree of lysis is dependent upon the chemical structure of the fatty acid, concentration, and duration of contact; unsaturated fatty acids are more effective than saturated fatty acids.

Tumor cells, when incubated at low concentrations of fatty acids, show stimulation of O2 uptake; however, in the bioassay these fatty acid-treated inocula showed no loss in tumor activity.

The nature of the physiochemical interaction between fatty acids and tumor cells is discussed.
A Stable "Bilirubin" Standard
Authors: Bilissis P K , Speer R J
Published: January 2020

An aqueous solution of N-(1-naphthyl) ethylenediamine dihydrochloride has been successfully employed as a routine secondary "bilirubin" standard. It possesses a stability which is, unfortunately, not a characteristic of bilirubin itself.
Protein Electrophoretic Analyses of Serum of Cancer Patients
Authors: Graham W Donald
Published: January 2020

The mean relative proportions of a number of blood serum protein fractions assessed electrophoretically are altered in active cancer. The changes in number and degree are generally greater than in other diseases; this may be a reflection of the seriousness of the condition and the extent of tissue involvement. A relative lowering of the proportion of albumin and an increase in that of the various globulins in "active" cancer was absent or much less apparent in treated cases.

Significant changes differ according to location of the malignancy. Proportions of the -globulins were not elevated in cancer of the gastrointestinal tract nor were those of the -globulins in prostatic cancer. Within the 2-globulins the central subfraction proportion was elevated most where tissue involvement was greatest, although in breast or prostate cancer the most pronounced alteration occurred in the proportion of the first 2-globulin subfraction. The subfraction of -globulin increased in proportion in cancer of the gastrointestinal tract differed from that elevated in cancer of the lung. Further refinement in fractionation techniques may reveal major differences in the serum protein distribution in different neoplasms. A considerable elevation of the 2-globulin proportion above the normal may be regarded as a sign of a poor prognosis.

Age had little significant effect with the exception of a rise in the third -globuIin subfraction proportion, which went through a maximum in the 50-59 year age group. The relative concentration of this same fraction was elevated in cardiovascular disease in hypertension and hypercholesterolemia.
A Simple Low-Voltage Paper Electrophoretic Method for the Determination of Urinary Vanillylmandelic Acid (VMA)
Authors: Eichhorn F , Rutenberg A
Published: January 2020

A simple and accurate method for the determination of urinary 3-methoxy-4-hydroxy-mandelic acid, vanillyl-mandelic acid (VMA), is described. The separation of VMA from all other phenolic acids in approximately 0.05 ml. untreated urine is achieved by using low-voltage paper electrophoresis with different buffer concentrations for the cathode and the anode. The concentration of the electrophoretically separated VMA is determined colorimetrically in the eluate. Values of excreted VMA in 24-hr. normal urine and those from subjects with pheochromocytoma differ considerably. We are now applying this new principle of "two solutions paper electrophoresis" for better separation of amino acids, proteins, and other biologic mixtures.
Microdetermination of Chloride in Blood Plasma and Cells, by Spectrophotometric Analysis Using Solid Silver Iodate
Authors: Rodkey F Lee , Sendroy Julius
Published: January 2020

As an extension of the silver iodate method of Sendroy, a convenient, reproducible, and sensitive method for analysis of chloride in 0.02-ml. samples of serum, whole blood, or red cells is described. The procedure involves (1) preparation of a protein-free filtrate of the sample, (2) Agl03 reaction with the filtrate, and (3) spectrophotometric analysis of iodine as the quantitative measure of the amount of iodate exchanged for chloride. Conditions important for each of these steps have been investigated. A precision of ± 0.85 (S.D.) mM CI per liter has been found for this method, the results of which are within 1% of those obtained by the macro nitric acid digestion method of Van Slyke.
Geographic assessment of cancer genome profiling studies
Authors: Carrio-Cordo Paula , Acheson Elise , Huang Qingyao , Baudis Michael
Published: January 2020

Cancers arise from the accumulation of somatic genome mutations, which can be influenced by inherited genomic variants and external factors such as environmental or lifestyle-related exposure. Due to the heterogeneity of cancers, precise information about the genomic composition of germline and malignant tissues has to be correlated with morphological, clinical and extrinsic features to advance medical knowledge and treatment options. With global differences in cancer frequencies and disease types, geographic data is of importance to understand the interplay between genetic ancestry and environmental influence in cancer incidence, progression and treatment outcome. In this study, we analyzed the current landscape of oncogenomic screening publications for geographic information content and quality, to address underrepresented study populations and thereby to fill prominent gaps in our understanding of interactions between somatic variations, population genetics and environmental factors in oncogenesis. We conclude that while the use of proxy-derived geographic annotations can be useful for coarse-grained associations, the study of geo-correlated factors in cancer causation and progression will benefit from standardized geographic provenance annotations. Additionally, publication-derived geographic provenance data allowed us to highlight stark inequality in the geographies of cancer genome profiling, with a near lack of sizable studies from Africa and other large regions.
Detrimental effects of cerebrospinal fluid pressure elevation on spinal cord perfusion: first-time direct detection in a large animal model
Authors: Haunschild Josephina , von Aspern Konstantin , Khachatryan Zara , Bianchi Edoardo , Friedheim Till , Wipper Sabine , Trepte Constantin J , Ossmann Susann , Borger Michael A , Etz Christian D
Published: January 2020

OBJECTIVES

Cerebrospinal fluid (CSF) drainage is routinely utilized to mitigate perioperative and postoperative spinal cord ischaemia in open and endovascular thoraco-abdominal aortic aneurysm repair to prevent permanent paraplegia. Clinical decision-making in the vulnerable perioperative period, however, is still based on limited clinical and experimental data. Our aim was to investigate the isolated effect of CSF pressure elevation on spinal cord perfusion in an established large animal model.

METHODS

Ten juvenile pigs with normal (native) arterial inflow (patent segmental arteries and collaterals) underwent iatrogenic CSF pressure elevation (×2, ×3, ×4 from their individual baseline pressure). Each pressure level was maintained for 30 min to mimic clinical response time. After the quadrupling of CSF pressure, the dural sac was slowly depressurized against gravity allowing CSF pressure to passively return to baseline values. Measurements were taken 30 and 60 min after normalization, and microspheres for regional blood flow analysis were injected at each time point.

RESULTS

Spinal cord perfusion decreased significantly at all mid-thoracic to lumbar cord segments at the doubling of CSF pressure and declined to values <53% compared to baseline when pressure was quadrupled. Normalizing CSF pressure led to an intense hyperperfusion of up to 186% at the cervical level and 151% within the lumbar region.

CONCLUSIONS

CSF pressure elevation results in a relevant impairment of spinal cord blood supply. Close perioperative and postoperative monitoring of CSF pressure is crucial for maintaining sufficient spinal cord perfusion. Radical and rapid withdrawal of CSF is followed by significant hyperperfusion in all spinal cord segments and may lead to ‘drainage-related’ iatrogenic reperfusion injury—aggravating the risk of delayed spinal cord injury—and should therefore be avoided.
Post-extrasystolic potentiation as a predictor of premature ventricular contraction–cardiomyopathy in an animal model
Authors: Kowlgi Gurukripa N , Ramirez Rafael J , Kaszala Karoly , Joslyn Martha , Koneru Jayanthi N , Ellenbogen Kenneth A , Tan Alex Y , Huizar Jose F
Published: January 2020

Aims

High premature ventricular contractions (PVCs) burden does not always predict the development of PVC-cardiomyopathy (CM). We sought to evaluate post-extrasystolic potentiation (PESP) of left ventricular ejection fraction (LVEF) to predict the severity of PVC-CM in an animal model.

Methods and results

Right ventricular apical bigeminal PVCs were introduced for 12 weeks in 11 canines to induce PVC-CM. Echocardiograms were performed to obtain LVEF without ectopy (Echo-1) and during PVCs (200 and 350 ms coupling intervals, Echo-2, and Echo-3, respectively), and premature atrial contractions (PACs) (Echo-4) at baseline and after 12 weeks of bigeminal PVCs. PESP was calculated as delta-LVEF between the sinus beat post-ectopy LVEF (Echo-2, -3, and -4, respectively) and LVEF without PVC (Echo-1) at baseline and 12 weeks of high PVC burden. A hyperdynamic LV function (LVEF > 70%) was noted in all animals only with early-coupled PVCs (LVEF at 200 ms: 74.4 ± 6%) at baseline. While PVC PESP at 200 ms had a strong significant correlation with the final 12-week LVEF (R = 0.8, P = 0.003), PVC PESP at 350 ms and PAC PESP had a positive but non-significant correlation (R = 0.53, P = 0.09, and R = 0.29, P = 0.34, respectively). Premature ventricular contraction PESP at 350 ms was significantly higher after PVC-CM had developed (delta-LVEF baseline 2.7 ± 2.9% vs. 12 weeks 18.6 ± 12.3% P < 0.001).

Conclusion

Bigeminal early-coupled PVCs cause hyperdynamic left ventricular function in the structurally normal canine heart due to PESP. The degree of PESP at baseline is inversely proportional to the PVC-CM severity at 12 weeks and maybe a predictor of PVC-CM as it may assess the myocardial adaptation reserve to PVCs.
Estimation of radiated energy using the KiK-net downhole records—old method for modern data
Authors: Kanamori Hiroo , Ross Zachary E , Rivera Luis
Published: January 2020

We use KiK-net (NIED) downhole records to estimate the radiated energy, ER, of 29 Japanese inland earthquakes with a magnitude range from Mw = 5.6 to 7.0. The method is based on the work of Gutenberg and Richter in which the time integral of S-wave ground-motion velocity-squared is measured as a basic metric of the radiated energy. Only stations within a distance of 100 km are used to minimize complex path and attenuation effects. Unlike the teleseismic method that uses mainly P waves, the use of S waves which carry more than 95 per cent of the radiated energy allows us to obtain robust results. We calibrate the method using synthetic seismograms to modernize and improve the Gutenberg–Richter method. We compute synthetic seismograms for a source model of each event with a given source function (i.e. known ER), the actual mechanism and the source-station geometry. Then, we compare the given ER with the computed energy metric to correct for the unknown effect of wave propagation and the mechanism. The use of downhole records minimizes the uncertainty resulting from the site response. Our results suggest that the currently available estimates of ER from teleseismic data are probably within a factor of 3, on average, of the absolute value. The scaled energy eR ( = ER/M0) is nearly constant at about 3 × 10−5 over a magnitude range from Mw = 5.6 to 7.0 with a slight increasing trend with Mw. We found no significant difference in eR between dip-slip and strike-slip events.
Multivariable inversion using exhaustive grid search and high-performance GPU processing: a new perspective
Authors: Venetis Ioannis E , Saltogianni Vasso , Stiros Stathis , Gallopoulos Efstratios
Published: January 2020

Exhaustive searches in regular grids is a traditional and effective method for inversion, that is numerical solution of systems of non-linear equations which cannot be solved using formal algebraic techniques. However, this technique is effective for very few (3–4) variables and is slow. Recently, the first limitation was to a major degree overpassed with the new TOPological INVersion (TOPINV) algorithm which was used for inversion of systems with up to 18, or even more unknown variables. The novelty of this algorithm is that it is not based on the principle of the mean minimum misfit (cost function) between observations and model predictions, used by most inversion techniques. The new algorithm investigates for each gridpoint whether misfits of each observation are within specified uncertainty intervals, and stores clusters of ‘successful’ gridpoints in matrix form. These clusters (ensembles, sets) of gridpoints are tested whether they satisfy certain criteria and are then used to compute one or more optimal statistical solutions. The new algorithm is efficient for highly non-linear problems with high measurement uncertainties (low signal-to-noise ratio, SNR) and poor distribution of observations, that is problems leading to complicated 3-D mean misfit surfaces without dominant peaks, but it is slow when running in common computers. To overcome this limitation, we used GPUs which permit parallel processing in common computers, but faced another computational problem: GPU parallel processing supports only up to three dimensions.

To solve this problem, we used CUDA programming and optimized the distribution of the computational load to all GPU cores. This leads up to 100x speedup relative to common CPU processing, as is derived from comparative tests with synthetic data for two typical inversion geophysical problems with up to 18 unknown variables, Mogi magma source modeling and elastic dislocation modeling of seismic faults. This impressive speedup makes the GPU/CUDA implementation of TOPINV practical even for low-latency solution of certain geophysical problems.

This speedup in calculations also permitted to investigate the performance of the new algorithm in relation to the density of the adopted grids. We focused on a typical problem of elastic dislocation in unfavorable conditions (poor observations geometry, data with low SNR) and on synthetic observations with noise, so that the difference of each solution from the ‘true’/reference value was known (accuracy-based approach). Application of the algorithm revealed stable, accurate and precise solutions, with quality increasing with the grid density. Solution defects (bias), mainly produced by very coarse grids, can be identified through specific diagnostic criteria, dictating finer search grids.
A causal inference perspective on the analysis of compositional data
Authors: Arnold Kellyn F , Berrie Laurie , Tennant Peter W G , Gilthorpe Mark S
Published: January 2020

Background

Compositional data comprise the parts of some whole, for which all parts sum to that whole. They are prevalent in many epidemiological contexts. Although many of the challenges associated with analysing compositional data have been discussed previously, we do so within a formal causal framework by utilizing directed acyclic graphs (DAGs).

Methods

We depict compositional data using DAGs and identify two distinct effect estimands in the generic case: (i) the total effect, and (ii) the relative effect. We consider each in the context of three specific example scenarios involving compositional data: (1) the relationship between the economically active population and area-level gross domestic product; (2) the relationship between fat consumption and body weight; and (3) the relationship between time spent sedentary and body weight. For each, we consider the distinct interpretation of each effect, and the resulting implications for related analyses.

Results

For scenarios (1) and (2), both the total and relative effects may be identifiable and causally meaningful, depending upon the specific question of interest. For scenario (3), only the relative effect is identifiable. In all scenarios, the relative effect represents a joint effect, and thus requires careful interpretation.

Conclusions

DAGs are useful for considering causal effects for compositional data. In all analyses involving compositional data, researchers should explicitly consider and declare which causal effect is sought and how it should be interpreted.
Emerging questions about merger notification and the Canadian response
Authors: Bester Keldon , Byers Jacqueline
Published: January 2020

Amid a global uptick in public interest in competition policy, questions have emerged about the fitness of tools available to international competition authorities, particularly in relation to the digital economy. Treatment of mergers has come under increased scrutiny, and while the competitive analysis of mergers is a rich vein of debate, equally important is the question of which mergers competition authorities decide to analyse at all. We provide a brief overview of the Canadian approach to pre-merger notification, the emerging challenges associated with but not limited to the digital economy, and the Canadian response thus far.
Outcomes following surgical management of inguinal-related groin pain in athletes: a case series
Authors: Gerhardt Michael , Christiansen Josh , Sherman Benjamin , Miranda Alejandro , Hutchinson William , Chahla Jorge
Published: January 2020

To determine the outcomes of a limited surgical intervention, consisting of neurolysis, inguinal wall repair and/or adductor debridement of adhesions based on intraoperative findings. Retrospective case series. Outpatient orthopedic/general surgery clinic. Fifty-one athletes treated surgically for inguinal-related groin pain from 2009 to 2015. Limited surgical intervention, consisting of neurolysis, inguinal wall repair and/or adductor debridement based on intra-operative findings. Ability to return to sport at the same level, time to return to play. Fifty-one athletes were included in the study with an average follow-up of 4.42 years (range 2.02–7.01). The average age was 24.2 years (range 16–49) and consisted of 94.0% males and 6.0% females. Nerve entrapment was demonstrated in 96.2% of cases with involvement of the ilioinguinal in 92.5%, the iliohypogastric in 30.8% and the genitofemoral in 13.2%. Attenuation of the posterior inguinal wall was present and repaired in 79.3% of cases. Scar tissue was present around the adductor origin and required debridement in 56.7% of cases. Forty-nine (96.1%) athletes returned to sport at the same level of play at an average of 5.9 weeks. Two athletes required a revision surgery. High rates of return to sport were achieved after surgery for inguinal-related groin pain that addresses the varying pathology and associated nerve entrapment.
Ligamentum teres reconstruction: indications, technique and minimum 1-year results in nine patients
Authors: O’Donnell J , Klaber I , Takla A
Published: January 2020

Ligamentum teres (LT) tear is a recognized cause of hip pain. Debridement of tears and capsule plication has shown satisfactory results. However, a group of patients with complete tears do not improve after debridement and physiotherapy. The purpose of this work was to describe the senior author’s technique and clinical results for the early series of LT reconstructions. Retrospective analysis of prospectively collected data. Patients who underwent isolated LT reconstruction between 2013 and 2018. All the patients had previous debridement of a completely torn LT, capsule plication and rehabilitation. Patients who had any other associated procedure during LT reconstruction surgery and dysplastic acetabular features were excluded. Demographic and clinical data was reviewed. Complications, type of graft and modified Harris hip scores (mHHSs) were recorded preoperatively and at 1-year follow-up. Fifteen LT reconstructions were performed during the study period. Six were excluded (as they had additional procedures performed during surgery) and nine patients aged a mean 30 (range: 22–48) years old were included. The patients had a mean of 2 (range: 1–4) prior surgeries. At minimum 12 months (range: 12–24) 9/9 patients reported reduction of pain and instability symptoms with mHHSs of 84.2 (73.7–100) versus 51.7 (36.3–70.4) preoperatively (P = 0.00094). Three patients (of the total cohort of 15) underwent second-look arthroscopy (11–22 months after reconstruction). None of these patients underwent total hip replacement at a mean of 4 (range: 1–6) years. Arthroscopic LT reconstruction improved function and pain in patients with persistent pain and instability after resection of the LT.
Conservative management acutely improves functional movement and clinical outcomes in patients with pre-arthritic hip pain
Authors: McGovern Ryan P , Martin RobRoy L , Phelps Amy L , Kivlan Benjamin R , Nickel Beth , Christoforetti John J
Published: January 2020

Conservative management for individuals with pre-arthritic hip pain is commonly prescribed prior to consideration of surgical management. The purpose of this study is to determine if patients with pre-arthritic hip pain will improve their functional movement control and clinical outcome measures following the implementation of physical therapy and a home-exercise programme. Information was retrospectively collected on consecutive patients and included: demographics, diagnosis, initial and follow-up evaluation of the single leg squat test (SLST) and step-down test (SDT), and patient-reported outcome measures. An independent t-test and one-way analysis of covariance were performed for continuous patient-reported outcome measures and a Fisher’s exact test was performed for patient satisfaction. Forty-six patients (31 female and 15 male) diagnosed with pre-arthritic hip pain were included. A total of 30 patients improved their functional movement control during performance of the SLST, whereas 31 patients improved performance of the SDT. There was a statistically significant difference between patients that improved and did not improve (P ≤ 0.017). Patients with pre-arthritic hip pain who improved their functional movement control following a prescribed rehabilitation intervention are likely to report less pain and greater functional ability in their daily and sports-related activities. This study supports conservative management to acutely improve outcomes for patients with pre-arthritic hip pain.
Justice Not Forgiveness: Perspectives on Justice and Reconciliation among Yazidi Women Refugees in Germany
Authors: Pham Phuong , Gibbons Niamh , Denkinger Jana Katharina , Junne Florian , Vinck Patrick
Published: January 2020

In August 2014, Islamic State (ISIS) jihadists overtook the Sinjar mountains of northern Iraq, committing widespread killing and abductions of Yazidi community members. Five years later, there is no comprehensive policy or programme to provide accountability and redress to survivors of ISIS. This article presents results from in-depth interviews with 117 Yazidi refugees resettled in the German Federal State of Baden-Württemberg in 2015–16 through the ‘Special Quota’ humanitarian assistance programme. The results provide an empirical assessment of Yazidi survivors’ views on justice and accountability. They also explore the tensions that exist at the intersection of global and national considerations for justice and reconciliation, and local values, needs, and priorities. The immediate need to find the missing and reunify families, and ensuring the safety and wellbeing of family members remaining in Iraq, are the respondents’ highest priority. The respondents also expressed a strong desire for truth and accountability. Recognition of the genocide, truth-seeking, and criminal prosecution are seen as important steps individually, and towards the protection of Yazidis as a group. The article addresses how those views relate to the possibility of a just and peaceful future in Iraq and the context of transitional justice options that have been proposed in response to ISIS crimes.
Signaling pathways underlying nitrogen-dependent changes in root system architecture: from model to crop species
Authors: Jia Zhongtao , von Wirén Nicolaus
Published: January 2020

Among all essential mineral elements, nitrogen (N) is required in the largest amounts and thus is often a limiting factor for plant growth. N is taken up by plant roots in the form of water-soluble nitrate, ammonium, and, depending on abundance, low-molecular weight organic N. In soils, the availability and composition of these N forms can vary over space and time, which exposes roots to various local N signals that regulate root system architecture in combination with systemic signals reflecting the N nutritional status of the shoot. Uncovering the molecular mechanisms underlying N-dependent signaling provides great potential to optimize root system architecture for the sake of higher N uptake efficiency in crop breeding. In this review, we summarize prominent signaling mechanisms and their underlying molecular players that derive from external N forms or the internal N nutritional status and modulate root development including root hair formation and gravitropism. We also compare the current state of knowledge of these pathways between Arabidopsis and graminaceous plant species.
Extreme variability in an active galactic nucleus: Gaia16aax
Authors: Cannizzaro G , Fraser M , Jonker P G , Pringle J E , Mattila S , Hewett P C , Wevers T , Kankare E , Kostrzewa-Rutkowska Z , Wyrzykowski Ł , Onori F , Harmanen J , Ford K E S , McKernan B , Nixon C J
Published: January 2020

We present the results of a multiwavelength follow-up campaign for the luminous nuclear transient Gaia16aax, which was first identified in 2016 January. The transient is spatially consistent with the nucleus of an active galaxy at z = 0.25, hosting a black hole of mass ${\sim }6\times 10^8\, \mathrm{M}_\odot$. The nucleus brightened by more than 1 mag in the Gaia G band over a time-scale of less than 1 yr, before fading back to its pre-outburst state over the following 3 yr. The optical spectra of the source show broad Balmer lines similar to the ones present in a pre-outburst spectrum. During the outburst, the H α and H β emission lines develop a secondary peak. We also report on the discovery of two transients with similar light-curve evolution and spectra: Gaia16aka and Gaia16ajq. We consider possible scenarios to explain the observed outbursts. We exclude that the transient event could be caused by a microlensing event, variable dust absorption or a tidal encounter between a neutron star and a stellar mass black hole in the accretion disc. We consider variability in the accretion flow in the inner part of the disc, or a tidal disruption event of a star ${\ge } 1 \, \mathrm{M}_{\odot }$ by a rapidly spinning supermassive black hole as the most plausible scenarios. We note that the similarity between the light curves of the three Gaia transients may be a function of the Gaia alerts selection criteria.