bluuebunny/crossref_metadata_2025 huggingface dataset:
Bismuth sulphide decorated ZnO nanorods heterostructure assembly via controlled SILAR cationic concentration for enhanced photoelectrochemical cells
Authors: AL-Zahrani A A , Zainal Z , Talib Z A , Lim H N , Holi A M
Published: January 2020

The current study investigates Bi2S3 thin films coated on ZnO NRAs with varying cationic concentrations through ionic layer adsorption and reaction (SILAR) technique. XRD patterns reveal that Bi2S3 is successfully synthesised and exhibits orthorhombic structure on the wurtzite ZnO NRAs. The band gap energy (Eg) of Bi2S3/ZnO NRAs shows a notable red shift with increasing cationic concentration. The photocurrent density increases significantly with increasing concentration from 1 mM to 3 mM before decreases at higher concentration due to agglomeration of Bi2S3 NPs and formation of recombination centres. The hybrid photoanode Bi2S3/ZnO NRAs at 3 mM exhibits the highest photocurrent value (1.92 mA cm−2), which is about six times greater than that of plain ZnO NRAs (0.337 mA cm−2). The high photoconversion efficiency value of 1.65% versus 0.5 V Ag A−1g−1C−1l−1 is obtained by Bi2S3/ZnO NRAs (3 mM) in comparison with pristine ZnO NRs, mainly due to the stepwise band alignment edge and significant enhancement of morphological and optical properties. The study reveals that controlling the cationic concentration can potentially improve the photoconversion efficiency.
Synthesis of silicon nanoparticles by laser ablation at low fluences in water and ethanol
Authors: Serrano-Ruz J A , Quiñones-Galván J G , Santos Cruz J , de moure-Flores F , Campos González E , Chávez-Chávez A , Gómez-Rosas G
Published: January 2020

Colloidal silicon nanoparticles (Si-nc) where synthesized by laser ablation of a solid Si target in water and ethanol. The target was immersed in a vessel containing the solvent and irradiated during 5 and 10 min at different fluences: 0.530, 0.608, 0.687 J cm−2. Ablation was carried out using a laser wavelength of 1064 nm. The obtained colloidal nanoparticles were irradiated after the synthesis to evaluate if laser fragmentation could be produced. In addition, a series of nanoparticles using ethanol as liquid medium was synthesized ablating with 532 nm. Colloidal nanoparticles were structurally characterized by Raman spectroscopy and Transmission Electron Microscopy. Size of the Si-nc were calculated by the theorical models: Bond Polarizability Model (BPM) and One-Phonon Confinement Model (PCM), where nanocrystals ranging from 2 to 11 nm were found.
Hot deformation behavior of the AA6016 matrix composite reinforced with in situ ZrB2 and Al2O3 nanoparticles
Authors: Fang Zheng , Zhao Yutao , Kai Xizhou , Tao Ran , Xia Chaoyi , Zhang Zhenyu , Sun Yue
Published: January 2020

The hot deformation tests of in situ ZrB2 and Al2O3 nanoparticles reinforced AA6016 matrix composite were studied at deformation temperature of 300 °C–450 °C and strain rate of 0.001–1 s−1. In this paper, the ZrB2 and Al2O3 nanoparticles were successfully prepared by direct melt reaction method firstly. Based on experimental results, the flow stress increased rapidly with the increasing true strain and decreased with the increasing temperature. Constitutive equation of the composite can be established based on the Arrhenius constitutive model. The processing map based on dynamic material model showed two stable processable domains: Domain A(300–360 °C/0.08–0.01 s−1), which was controlled by dynamic recovery and domain B(410–430 °C/0.37–1 s−1), which was typical dynamic recrystallization structure. The microstructural changes of the samples after deformed were observed through optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). It was concluded that these two kinds of reinforced particles can greatly promote recrystallization nucleation at high temperatures. Thus, domain B is optimum hot processing window.
Extraction of magnesium from garnierite by carbothermal reduction in vacuum
Authors: Gu Xu-peng , Qu Tao , Shi Lei , Wang Qiang , Yang Bin , Dai Yong-nian
Published: January 2020

The aim of the traditional pyrometallurgical processes is to extract nickel and iron in garnierite, but it is difficult to extract magnesium of higher value in minerals. Aimed at solving this problem, the extraction of magnesium from garnierite is proposed and studied in this study. The effects of different reduction temperatures, different reduction times and dosage of CaO additions in experiments were investigated. The experimental results indicate that the extraction rate of magnesium can reach 93.23% when the mass ratio of mineral/reductant is 100:28.3, system pressure is 50 Pa, reduction temperature is 1823 K, and reduction time is 120 min, and, at the same time, the purity of metal magnesium in the condensate can be up to 91.88%. Under these conditions, the extraction rate of magnesium can increase to 99.45% by adding 25 wt% CaO, and the purity of the metal magnesium in the condensate exceeds 90%. CaO as the additive can effectively improve the extraction rate of magnesium and promote the recovery and utilization of magnesium. The mechanism is that CaO replaces –O–Mg– in the –O–Mg−O–Si−O– structure to form free MgO, which is reduced to Mg vapor by carbon and condensed into magnesium metal in the condensation zone to achieve the purpose of removing and collecting Mg from the garnierite. At the same time, the reduced slag is rich in Ni and Fe, which can be used for the extraction of Ni and Fe. Compared with the traditional pyrometallurgical process, the process can extract magnesium from garnierite, and the process is short and its operation is simple, which is a potential technology.
Effect of nanoparticles loading on free vibration response of epoxy and filament winding basalt/epoxy and E-glass/epoxy composite tubes: experimental, analytical and numerical investigations
Authors: Ilangovan S , Senthil Kumaran S , Naresh K
Published: January 2020

In recent times, basalt fiber reinforced polymer (BFRP) nanocomposites is being increasingly used in aerospace applications such as wing and fuselage structures of the aircraft and outer casings of the rocket, automobile engine drive shafts and fuel tanks in the oil and gas industries, which fills the gap between carbon and E-glass fiber reinforced polymer nanocomposites. These structures are subjected to vibrations and exposed to different temperatures in various places during their service life. However, the comparison of vibration response of silica particles reinforced basalt/epoxy and glass/epoxy nanocomposite tubes in all three approaches, namely, experimental, analytical and numerical (Finite Element Modeling), have not found elsewhere. Analytical and numerical approaches minimize time, manpower and cost. Therefore, investigating the vibration response of different weight contents of these FRP nanocomposite tubes is novel and essential. Hence, in this study, the vibration response of silica nanoparticles reinforced epoxy, basalt/epoxy and E-glass/epoxy composites with different weight contents (0, 0.5, 1 and 1.5%) were investigated. The vibration tests were performed at three different boundary conditions such as cantilever, simply supported and fixed-fixed. The first three modes of vibration were considered for analysis. Besides, the heat deflection temperature and the hardness properties were also studied. The results indicate that the natural frequencies were higher for the fixed-fixed case and the damping parameters were higher for the simply supported case. Vibration properties, heat deflection temperature and hardness values were found to be higher in fiber-reinforced nanocomposites than those of epoxy nanocomposites. The data presented in this study will be useful to generate the numerical models for the ground vibration test (GVT).
Optically polarized selection in atomic vapor and its application in mapping the polarization distribution
Authors: Wang Jinwen , Chen Yun , Yang Xin , Liu Jun , Qiu Shuwei , Cao Mingtao , Chen Haixia , Wei Dong , Müller-Dethlefs Klaus , Gao Hong , Li Fuli
Published: January 2020

Based on the dichroism induced by the optical pumping effect, a novel and effective configuration to select an arbitrary polarization distribution is proposed. The influence of the distribution of atoms in different Zeeman sub-levels is the main cause to realize the measurement or ‘filtration’ of the state of polarization. A detailed process of the optical pumping effect in our configurations is presented in the theoretical analysis. In the experiment, the flexible function of the atomic medium, such as a polarizer or a polarized filter can efficiently be realized by different polarizations of the pump beam. Four different kinds of vector beams are tested and the ability to analyze any kind of beam with arbitrary polarization distribution is proven in agreement with the prediction. This work has potential applications in atomic physics and polarization optics. Furthermore, it can provide a reference to atom-optical elements and atom-optical devices.
Ancient species offers contemporary therapeutics: an update on shark VNAR single domain antibody sequences, phage libraries and potential clinical applications
Authors: English Hejiao , Hong Jessica , Ho Mitchell
Published: January 2020

The antigen binding variable domain (VNAR) of the shark immunoglobulin new antigen receptor (IgNAR) evolved approximately 500 million years ago and it is one of the smallest antibody fragments in the animal kingdom with sizes of 12–15 kDa. This review discusses the current knowledge of the shark VNAR single domain sequences and ongoing development of shark VNARs as research tools as well as potential therapeutics, in particular highlighting the recent next-generation sequencing analysis of 1.2 million shark VNAR sequences and construction of a large phage displayed shark VNAR library from six naïve adult nurse sharks (Ginglymostoma cirratum). The large phage-displayed VNAR single domain library covers all the four known VNAR types (Types I–IV) and many previously unknown types. Ongoing preclinical development will help define the utility of shark VNAR single domains as a potentially new family of drug candidates for treating cancer and other human diseases.
Knee pain and future decline in higher-level functional competence in community-dwelling older Japanese: the Kurabuchi cohort study
Authors: Sugai Keiko , Michikawa Takehiro , Takebayashi Toru , Nishiwaki Yuji
Published: January 2020

Background

The effect of knee osteoarthritis, which causes knee pain, on higher-level functional competence (HLFC) is not clear.

Objective

To clarify the effect of knee pain on HLFC in older people.

Design

Community-based prospective cohort study.

Setting

Kurabuchi town, Gumma prefecture, Japan.

Subjects

Community-dwelling individuals aged 65 and older.

Methods

A total of 808 residents participated to the baseline examinations. The frequency of knee pain, degree of pain and functional impairment resulting from the pain were asked at baseline (2005–2006) via a self-administered questionnaire in Japanese based on an English version of the Western Ontario and McMaster Universities Osteoarthritis Index. Information on HLFC at baseline and during home visits were collected annually until 2014 with the Tokyo Metropolitan Institute of Gerontology Index of Competence. The association between baseline knee pain and HLFC decline was assessed with a Cox proportional hazards model.

Results

Two factors, persistent knee pain and severe functional impairment caused by the pain, were significantly associated with future declines in total HLFC, with adjusted hazard ratios (95% confidence intervals) of 1.51 (1.08–2.11) and 1.49 (1.10–2.00). In analysis by subcategory, persistent knee pain had a significant adverse effect on participants’ intellectual and social activities, and that severe physical functional impairment also had a significant impact on social activities.

Conclusions

The clear association of the frequency of knee pain and resultant functional impairment with future HLFC decline indicates that collecting information about these factors may be useful in identifying older people at high risk of future HLFC decline.
CoMeBack: DNA methylation array data analysis for co-methylated regions
Authors: Gatev Evan , Gladish Nicole , Mostafavi Sara , Kobor Michael S
Published: January 2020

Motivation

High-dimensional DNA methylation (DNAm) array coverage, while sparse in the context of the entire DNA methylome, still constitutes a very large number of CpG probes. The ensuing multiple-test corrections affect the statistical power to detect associations, likely contributing to prevalent limited reproducibility. Array probes measuring proximal CpG sites often have correlated levels of DNAm that may not only be biologically meaningful but also imply statistical dependence and redundancy. New methods that account for such correlations between adjacent probes may enable improved specificity, discovery and interpretation of statistical associations in DNAm array data.

Results

We developed a method named Co-Methylation with genomic CpG Background (CoMeBack) that estimates DNA co-methylation, defined as proximal CpG probes with correlated DNAm across individuals. CoMeBack outputs co-methylated regions (CMRs), spanning sets of array probes constructed based on all genomic CpG sites, including those not measured on the array, and without any phenotypic variable inputs. This approach can reduce the multiple-test correction burden, while enhancing the discovery and specificity of statistical associations. We constructed and validated CMRs in whole blood, using publicly available Illumina Infinium 450 K array data from over 5000 individuals. These CMRs were enriched for enhancer chromatin states, and binding site motifs for several transcription factors involved in blood physiology. We illustrated how CMR-based epigenome-wide association studies can improve discovery and reduce false positives for associations with chronological age.

Availability and implementation

https://bitbucket.org/flopflip/comeback.

Supplementary information

Supplementary data are available at Bioinformatics online.
A robust method for shift detection in time series
Authors: Dehling H , Fried R , Wendler M
Published: January 2020

We present a robust and nonparametric test for the presence of a changepoint in a time series, based on the two-sample Hodges–Lehmann estimator. We develop new limit theory for a class of statistics based on two-sample U-quantile processes in the case of short-range dependent observations. Using this theory, we derive the asymptotic distribution of our test statistic under the null hypothesis of a constant level. The proposed test shows better overall performance under normal, heavy-tailed and skewed distributions than several other modifications of the popular cumulative sums test based on U-statistics, one-sample U-quantiles or M-estimation. The new theory does not involve moment conditions, so any transform of the observed process can be used to test the stability of higher-order characteristics such as variability, skewness and kurtosis.
Upper limb isometric exercise protocolled programme and arteriovenous fistula maturation process
Authors: Tapia González Irati , Esteve Simó Vicent , Ibañez Pallares Sara , Moreno Guzman Fátima , Fulquet Nicolás Miquel , Duarte Gallego Verónica , Saurina Solé Anna , Pou Potau Mónica , Yeste Campos Montserrat , Ramírez de Arellano Serna Manel
Published: January 2020

Introduction

Arteriovenous fistula (AVF) is the gold standard for vascular access (VA) for end-stage chronic kidney disease (CKD) patients. Post-operative exercises may help to improve maturation. Nevertheless, scarce scientific evidence has been reported about their utility to date. Our objective was to assess the effect of a post-operative isometric exercise programme on native VA maturation in patients with stage 5–5D CKD.

Methods

We performed a 24-month prospective study. After surgery, patients were randomized to the isometric exercise group (EG) or control group (CG). An isometric exercise protocolled programme was performed in the EG. The CG received usual care. Demographic data, muscle strength using a hand-grip (HG) dynamometer, main Doppler ultrasound (DUS) measurements, clinical and DUS maturation and VA complications were assessed at 4 and 8 weeks post-operatively.

Results

For 60 sixty patients (30 in the EG), demographic data and HG and DUS measurements at baseline were similar. A significant increase in HG was observed only in the EG at the end of the study (20.7 ± 8.1 versus 25.1 ± 10.3 kg, P = 0.001). The EG obtained the highest clinical maturation at 4 (CG 33.3% versus EG 70%, P = 0.009) and 8 weeks (CG 33.3% versus EG 76.7%, P = 0.002). Similarly, DUS maturation was better in the EG at 4 (CG 40% versus EG 80%, P = 0.003) and 8 weeks (CG 43.3% versus EG 83.3%, P = 0.003) and remained so in the EG for both distal and proximal VA territories for all these periods.

Conclusions

The upper limb isometric exercise protocolled programme improved clinical and DUS maturation in our patients in both the distal and proximal VA territories. Further studies are required to support these results.
Adaptation of Babson's Method for the Determination of Serum Glutamic Oxalacetic Transaminase in the Clinical Laboratory
Authors: Furuno Masaki , Sheena Albert
Published: January 2020

Babson's method for the assay of serum glutamic oxalacetic transaminase (SGO-T) is modified to increase its accuracy and reliability. The final color produced is made stable with the addition of bisulfite ion, thereby making the procedure more suitable for the routine clinical laboratory. The 95% limits for values on 20 healthy laboratory workers was 4 to 26 units with a mean of 13 units.
Use of a Screening Procedure for Blood Urea Nitrogen
Authors: McNair R D
Published: January 2020

The results of a paper strip test for blood urea nitrogen were compared with the values obtained by automatic analysis. The short procedure satisfactorily differentiates normal from abnormal levels and can be conveniently used for emergency determinations.
A New Method for the Determination of Nitrofurantoin in Urine
Authors: Conklin John D , Hollifield Richard D
Published: January 2020

Nitrofurantoin is presently used as an antibacterial agent for the urinary tract of both man and animals. A new, quantitative procedure for the determination of this drug in urine consists of direct extraction of the nonionized form of the drug by the use of nitromethane, addition of an alkaline reagent to the extract to produce a visible color, and determination of the nitrofurantoin concentration by spectrophotometry. The method has a sensitivity of 5 mg./L., with recoveries of 99-101% and a standard curve that is linear to 100 mg./L. Results indicate that the method measures nitrofurantoin alone, and not its metabolites, in rat, dog, and human urine.
Stabilization and Preservation of Serum Prostatic Acid Phosphatase Activity
Authors: Doe Richard P , Mellinger George T , Seal Ulysses S
Published: January 2020

The effects of pH and temperature of storage on the stability of the prostatic fraction of serum acid phosphatase activity have been studied in order to provide a satisfactory method for the preservation of activity in serums shipped from other hospitals. Addition of citrate tablets of a composition to buffer the serums at pH 6.2 was found to preserve the original activity at 25° for at least 7 days. These results were validated on a series of serums, subdivided into control and citrate-containing aliquots, shipped from the participating hospitals.
An Automated Trihydroxyindole Procedure for the Differential Analysis of Catecholamines
Authors: Robinson Robert L , Watts Daniel T
Published: January 2020

An automated trihydroxyindole procedure for the differential estimation of epinephrine and norepinephrine in tissues, urine, and blood is presented in detail. After an initial purification of the catecholamines by adsorption on aluminum oxide, the neutralized eluates are subjected to automatic analysis, in which potassium ferricyanide and an alkaline stabilizing agent are automatically mixed sequentially with the dialyzed catecholamines. The fluorescent trihydroxyindole derivatives formed are then delivered to a flow cell in a fluorometer and the fluorescence recorded. A differential estimation is obtained by running samples through the system, first with ascorbic acid stabilization to obtain the combined fluorescence of both amines and then with thioglycolic acid stabilization to obtain the fluorescence of norepinephrine alone.
A Direct-Reading Bilirubinometer Incorporating Hemolysis and Turbidity Correction
Authors: Jackson Sanford H
Published: January 2020

An instrument has been developed by which the bilirubin concentration in serum is determined spectrophotometrically. A reading of the difference in absorbance at 450 mµ and 540 mµ is obtained. The presence of hemoglobin or turbidity is corrected for, so that the differential absorbance reading, multiplied by a calibration factor, gives the correct bilirubin concentration. Comparisons with analyses using a Zeiss PMQ spectrophotometer agree closely.
Improved Instrumentation for the Determination of Prothrombin Activity
Authors: Sterling Rex E , Wilcox Alan A , Ware Arnold G , Umehara Mary K
Published: January 2020

The one-stage prothrombin method of Ware and Stragnell (2) has been semiautomated. This method employs an automatic pipetter-diluter and an end-point detector. These instruments materially increase the output per technician.
Coulometric Determination of Protein Nitrogen
Authors: Christian Gary D , Knoblock Edward C , Purdy William C
Published: January 2020

A coulometric method is described for the determination of ammonia resulting from micro-Kjeldahl digestion of protein samples. The method has been applied to the direct titration of the ammonia in the digests. Routine titration of the ammonia resulting from 10-µl. serum samples is described; the method has been applied to 1-µl. samples. Results are compared with standard macro- and micro-Kjeldahl procedures.
Method for Tissue Hemoglobin Analysis
Authors: Andersen Daniel , Shoemaker William C
Published: January 2020

A colorimetric method for analysis of the red cell content of tissues is described, and compared with an independent radioassay method. The introduced method is based upon acid extraction of tissue, treatment with base, and adsorption of the remaining turbidity with lauryl sulfate. Preliminary data are presented on the reproducibility of the colorimetric method on multiple biopsies of the canine liver. Red cell content of biopsies obtained from a series of normal dogs was 0.031 ml./gm. of liver tissue with a standard deviation of ± 0.011. The red cell content of the liver of dogs in various physiologic conditions ranged up to 0.096 ml./gm. of liver tissue.
An Enzymatic Method for Glucose Quantitation in Normal Urine
Authors: Keller Daniel M
Published: January 2020

A method to quantitate the glucose concentration in normal urine is described and evaluated. It utilizes the enzymes hexokinase and glucose-6-phosphate dehydrogenase and depends on measuring NADPH2 absorbance at 340 mµ.
Separation and Determination of the Total Globulins of Human Serum
Authors: RodKey F Lee
Published: January 2020

A method for isolation and determination of total globulins of human serum, carried out in a single tube without transfer, is described. Serum is treated with 2% (w/v) TCA in ethanol at room temperature to precipitate the globulins quantitatively as a gelatinous white precipitate easily recovered by centrifugation. The supernatant fluid is discarded and the precipitate washed with 2% TCA in ethanol. The globulin precipitate is dissolved in dilute NaOH and biuret reagent is added. There is no interference in the analysis of highly lipemic, icteric, or hemolyzed samples. The method has been applied to a number of abnormal serums, and the reproducibility determined. The globulin precipitation is more reproducible than salt fractionation, and no ether is required for the separation of the albumin from the globulin.
Immunoglobulin Components of "Gamma" Globulin in Human Serum
Authors: Trevorrow Virginia E , Merrill Deborah , Claman Henry N
Published: January 2020

Total gamma globulin was measured after paper electrophoresis of 40 human sera. Gamma G, γ A, and γ M immunoproteins were measured in these sera by single diffusion in agar gel. The total gamma globulin was found to consist primarily of γ G and γ M proteins, with a small portion of the γ A also included.
Relative Rates of Color Development of 17-Keto- and Ketogenic Steroids in the Zimmermann Reaction
Authors: Liu John HC
Published: January 2020

The rates of reaction at 27° 37°, 47°, and 57°, of 17-ketosteroids (17-KS), dehydroisoandrosterone (DHA), and 17-ketogenic steroids (17-KGS) were studied by a modified Zimmermann color reaction. Curves were constructed by plotting absorbance against time necessary for maximum color development at these temperatures. Pooled eluates of 17-KS and 17-KGS from normal urine samples were used in the determinations. Temperature was plotted against the time found necessary for maximum color development using DHA as standard. Experimental results conformed to the temperature-dependence theory of reaction rates, that for every 10° rise, the rate of reaction doubles. Curves of the absorbances at various times of incubation were calculated as percentiles of maximum color formation at each temperature. The interrelationship between 17-KS, 17-KGS, and DHA with respect to optimum reading time was noted. The significance of the finding that the rate of reaction of 17-KGS is much greater than that of 17-KS and DHA is demonstrated. Functional group contribution to the rate of reaction is discussed, as are other factors affecting the Zimmermann color reaction.
Data Processing in Clinical Chemistry
Authors: Peacock Andrew C , Bunting Sylvia L , Brewer Donna , Cotlove Ernest , Williams George Z
Published: January 2020

The flow of data in the clinical chemistry laboratory has been studied with respect to the types of personnel handling it and the ultimate use of the data. In order to promote higher efficiency, a data processing system using punched cards has been devised and operated for a period of approximately 24 months.

Forms, cards and general considerations useful in such a system are described in detail. Some of the problems associated with this type of operation are discussed, as are the economics of this system and its general applicability.
Separation of Erythrocytes of Different Ages
Authors: O'Connell Daniel J , Caruso Carmine J , Sass Martin D
Published: January 2020

Several methods have been evaluated for the separation of red cells of different ages on the basis of density differences. Simple sedimentation and flotation technics have been found to be unsatisfactory. Centrifugation, followed by a modified sampling procedure, has been demonstrated to provide excellent separation of erythrocyte populations of different ages. Standardization of centrifuge conditions and special precautions against redistribution of red-cell layers have contributed toward an improved and reproducible method for the separation of erythrocytes for subsequent study.
An Improved Automated Determination of Serum Total Cholesterol with a Single Color Reagent
Authors: Block Walter D , Jarrett K John , Levine Jacob B
Published: January 2020

An anhydrous color reagent containing ferric chloride is pumped through Tygon tubing to a glass coil in a 95° heating bath. Manually prepared serum extracts (1:20 isopropanol dilution) are presented to the stream of preheated color reagent, and the two are passed through three mixing coils, connected in series. The absorbance of the resultant color is determined at 550 mµ in a 15 mm. tubular flow-cell.

The improved N-automated procedure gave values of greater precision (5.6%) for total cholesterol determined in replicate samples from sera pools than the N-automated procedure which lacked precision (27.7%). The values found in 60 individual serums are within 6.0% of total cholesterol values determined by the Abell et al. method.
Phenolphthalein Monophosphate as a Substrate for Serum Alkaline Phosphatase
Authors: Wilkinson J H , Vodden Ann V
Published: January 2020

The procedure for serum alkaline phosphatase determination employing phenolphthalein monophosphate as substrate was evaluated under routine clinical laboratory conditions. A straight-line response to increasing serum concentration was observed, and the reaction was shown to be Mg++ dependent. The method proved to be extremely simple, and the results obtained correlated well with those given by a standard routine procedure involving determination of the liberated inorganic phosphate.
Concentration of Cerebrospinal Fluid Proteins and Their Fractionation by Cellulose Acetate Electrophoresis
Authors: Kaplan Alex , Johnstone Murray
Published: January 2020

Various technics for concentrating cerebrospinal fluid (CSF) prior to electrophoretic separation of the protein fractions were tested. Vacuum ultrafiltration through a collodion sac proved to be the most reliable and convenient method. The proteins in the concentrate were separated by cellulose acetate electrophoresis and quantitated densitometrically.

The mean values for the various protein fractions in normal CSF were the following: 4.9% pre-albumin, 61.5% albumin, 4.5% α1 globulin, 6.7% α2 globulin, 13.7% β globulin, and 8.8% γ globulin.
Specificity of the Free Fatty Acid Titration by the Method of Dole, Modified According to Trout
Authors: Parijs J , Barbier F , Elewaut A
Published: January 2020

The specificity of free fatty acid (FFA) titration is significantly enhanced when the modification of Trout (5) is used and the heptane extract washed with dilute sulfuric acid. Lactate, pyruvate, acetate, β-hydroxybutyrate, α-ketoglutarate, citrate, and urate, in concentrations found in normal human plasma, will not interfere with the titration. It can be expected that in some exceptional pathologic conditions, lactate, pyruvate, acetate, β-hydroxybutyrate, and urate will not be completely removed from the heptane extract. Salicylate seems to cause considerable interference. Trout's procedure substantially reduces the interference caused by phospholipids.
Automated Determination of Acid Phosphatase
Authors: Klein Bernard , Oklander Morris , Morgenstern Stanley
Published: January 2020

A procedure is presented for the automated determination of acid phosphatase activity in biological materials using the Robot Chemist. Although either phenylphosphate and α-naphthylphosphate may be used as substrate in this analysis, the procedure is described in detail for serum acid phosphatase using α-naphthylphosphate in 0.1 M citrate, pH 5.2, since this substrate is more selective for prostatic acid phosphatase in human serum. Enzymically generated aα- naphthol is determined by the Emerson reaction (alkaline aminoantipyrine and ferricyanide), modified for use with this automated system. Correlations are presented between the results obtained on the Robot Chemist and the identical procedure developed for the AutoAnalyzer.
Elimination of False Negative Results with the FPN Forrest Test for Phenothiazine Derivatives in Urine
Authors: Forrest Irene S , Forrest Fred M , Kanter Saul L
Published: January 2020

With the FPN Forrest test for urinary phenothiazine derivatives, omission of drug intake was found to be the most frequent cause of negative color reactions; accordingly, these negative reactions are true negatives. Excessive dilution of urine specimens occasionally yielded "apparent false negatives" by producing traces of drug metabolites, which cannot be detected without modification of the test. When measures to eliminate these conditions are taken, the previously specified reading time (10 sec. after mixing urine and reagent) is reliable. Unspecific color development due to reaction between endogenous urinary constituents and reagent appeared with a delay of 30 sec. or more, and hence recent recommendations of delaying reading times for the test were found to be unsuitable and productive of false positives.
The Automated Determination of Acetoacetate in Serum and Urine
Authors: Klein Bernard , Oklander Morris
Published: January 2020

A procedure based on the Rothera reaction is presented for the automated determination of acetoacetate in serum and urine. The mean serum acetoacetate concentration determined by this procedure for normal human subjects is 0.20 mM; S.D. is 0.059 mM. Recovery experiments demonstrate excellent reliability. The interferences are identified and their effects evaluated.
Comparison of Serum Magnesium Values by Photometric, Fluorometric, Atomic Absorption, and Flame Emission Methods
Authors: Pruden Elizabeth L , Meier Rebecca , Plaut David
Published: January 2020

Magnesium was determined on aliquots of the same serum by atomic absorption and flame emission spectrophotometry, by Titan Yellow and Magon photometry, and by 8-hydroxy-quinoline and 8-hydroxy-quinoline-sulfonate fluorometry. Comparison is presented of reproducibility of results by the various methods and of the normal values obtained.
Determination of Copper and Zinc in Biological Material
Authors: Parker Mary M , Humoller Fred L , Mahler Delmar J
Published: January 2020

Copper and zinc are readily determined in biological material by atomic absorption spectrophotometry. Two procedures are presented for the quantitative estimation of these metals in serum. One of these involves simple dilution and aspiration into the burner of the instrument. Suitably prepared standards must be used. The other method involves trichloroacetic acid preparation of the proteins prior to aspiration. With both methods satisfactory results in precision and recovery of added metals are obtained. Urinary copper determinations require chelation of the metal with ammonium pyrrolidino dithiocarbamate or some similar sequestering agent and concentration by extraction of the chelate into a suitable organic solvent. A similar procedure must be used in analyzing cow's milk for copper. Tissue analysis requires heating with boiling nitric acid and removal of the acid under reduced pressure prior to aspiration into the burner. It has been shown that procedural errors in such determinations are very much smaller than biological variation.
A Modified Copper Method for the Estimation of α-Amino Nitrogen in Urine
Authors: Clayton C C , Steele Betty F
Published: January 2020

The copper method of Pope and Stevens (1) for estimation of α-amino N has been modified by a change in buffer and the use of tetraethylenepentamine as a color intensifier, giving a good colorimetric assay. α-Amino N was measured successfully in concentrations of 0.2-2.8 mg./10 ml. Interference due to ammonia has been minimized, and interference due to certain other materials has been determined with suggestions for its elimination. The modified procedure offers the advantages of simplicity and speed in obtaining an approximate determination of α-amino N in urine.
Hemiglobin Sodium Nitrite vs. Hemiglobin Potassium Ferricyanide
Authors: Theil George B , Auer James E
Published: January 2020

A number of different spectrophotometric patterns have been described for methemoglobin (hemiglobin). These appear to be a function of the oxidizing agent employed. Only the 630-nm peak is common to hemiglobin formed by the addition of sodium nitrite or potassium ferricyanide to oxyhemoglobin.
Microestimation of Fibrinogen with a Semimicro Modification Applicable to Icteric Plasma
Authors: Goodwin Jesse F
Published: January 2020

The sulfite precipitation technic for fibrinogen has been modified to assay micro-volumes of plasma and eliminate interference from bilirubin. The precipitated fibrinogen is dissolved in urea and reacted with a modified biuret reagent. The resulting biuret complex may be read at 320 or 540 mµ. Bilirubin interference is eliminated by an oxidation step employing NaOCl and citric acid. The values obtained by the modified technics compare favorably with each other and with the macroprocedure.
Automated Simultaneous Calcium and Phosphorus Analysis
Authors: Klein Bernard , Kaufman James H , Isaacs John
Published: January 2020

A procedure is described for the automated simultaneous determination of serum calcium and phosphorus. Calcium is assayed fluorometrically; phosphorus is determined spectrophotometrically by the molybdenum blue reaction in an improved flow system with a more sensitive reducing agent.
Spectrophotometric Measurements of Serum Nickel
Authors: Sunderman F William
Published: January 2020

An ultraviolet spectrophotometric procedure has been developed for the measurement of serum nickel. Samples of serum are lyophilized and the dry residues are subjected to acid digestion. Nickel is separated from interfering elements by chloroform extraction of nickel dimethylglyoximate at alkaline pH. Nickel is converted to the diethyldithiocarbamate complex and is extracted with isoamyl alcohol. The absorbance of nickel bisdiethyldithiocarbamate is measured as the difference between the absorbance maximum (325 mµ) and the absorbances at 2 background wave lengths (295 and 355 mµ). The concentrations and volumes of the reagents have been adjusted in order to achieve a sensitivity of 0.002 ppm (2 µg/L.). The recovery of 2.5 µg. of nickel added to 8 samples of serum averaged 104% (S.D. ± 8), with a range from 91 to 115%. The mean concentration of nickel in serum from 23 normal subjects was 2.2 µg/100 ml. (S.D. ± 1.8), with a range from 0.1 to 7.7 µg/100 ml. The median concentration of serum nickel was 1.7 µg/100 ml.
Determination of Glutamic Oxalacetic Transaminase Activity by Coupling of Oxalacetate with Diazonium Salts
Authors: Sax Sylvan M , Moore John J
Published: January 2020

A method for measuring serum glutamic oxalacetic transaminase activity is described, in which substrate concentrations are more nearly optimal than in previous colorimetric methods. By coupling the diazonium salt at a pH of 4.2, interference from α-oxoglutarate is negligible. Oxalacetate is produced at a linear rate to 180 I.U. Results correlate well with those obtained by a reference spectrophotometric method.
Determination of Unconjugated and Total N-Acetyl-p-aminophenol (NAPA) in Urine and Serum
Authors: Heirwegh Karel P M , Fevery Johan
Published: January 2020

A sensitive and accurate method is described for the determination of N-acetyl-p-aminophenol (NAPA) and its metabolites in urine and serum. In strongly acidic medium, p-aminophenol (PAP) resulting from differential extraction and acid hydrolysis of total NAPA and unconjugated NAPA, is diazotized and the diazonium salt coupled with N-(1-naphthyl)ethylenediamine (NED) in the presence of ethanol. The blue azo dye formed is determined spectrophotometrically. Application to liver disease is briefly reported.
Automated Method for the Determination of Serum Creatine Kinase Activity
Authors: Fleisher Gerard A
Published: January 2020

An automated (AutoAnalyzer) method for the colorimetric determination of creatine kinase activity in serum is described. This method includes reactivation of creatine kinase with cysteine, incubation of the active enzyme with creatine phosphate and adenosine diphosphate at 37.5°, and subsequent inactivation of enzyme and binding of cysteine by phenylmercuric borate. The enzymatically produced creatine is dialyzed against a solution of diacetyl and reacted with α-naphthol in an alkaline solution. The absorbance of the colored end product is measured at 550 mµ. Individual blanks are determined in the absence of adenosine diphosphate. Comparison of results obtained by this method and a manual procedure shows satisfactory agreement.
Porphyrin Patterns in Different Types of Porphyria
Authors: Chu T C , Chu Edith Ju-Hwa
Published: January 2020

Porphyrins from 38 cases of different types of porphyria were separated chromatographically and analyzed. Patients with different types of porphyria eliminated porphyrins with different patterns. Simple paper chromatography of the methyl ester of the total porphyrin of a urine sample revealed a chromatographic pattern of the porphyrins characteristic of the type of porphyria. The relative abundance of the heptacarboxylic and uroporphyrins in a sample also differentiated porphyria cutanea tarda from acute intermittent or congenital porphyria. The isomer compositions of the porphyrins were also disclosed. While one type of isomer might dominate one type of porphyria, the magnitude of predominance was by no means unanimous, or even reversed, among the porphyrins from uro- through the intermediates to coproporphyrins. For example, in cutanea tarda, Type I isomer dominates uro- and pentacarboxylic porphyrins, and Type Ill isomer dominates the hepta-, hexa- and coproporphyrins. The complexity of the enzymatic reaction involved in the decarboxylation of the porphyrins is thus indicated.
Kinetic Parameters of Continuous Flow Analysis
Authors: Thiers R E , Cole R R , Kirsch W J
Published: January 2020

Unlike systems of batch analysis, continuous flow systems possess kinetic parameters. Associated with the steady state are such measurements as noise level and drift. This study reports on kinetic parameters associated with the transient state between the steady states including time required to change from base-line steady state to sample steady state and vice versa, characteristics of this change, time interval between samples, proportionality of sampling and washing time, fraction of steady state reached in any given sampling time, and interaction between samples. The transition between steady states has been found to obey first order kinetics to a good first approximation. This observation enables correlation of all of the above listed properties in quantitative fashion using new characteristic constants for continuous flow-the half-wash time (W1/2) and the lag phase time (L). These parameters, well known in other contexts such as radioactivity, can be employed as "figures of merit" for any continuous flow system or component, can be utilized to calculate performance characteristics, and are useful in evaluating and optimizing over-all performance.
Hippuric Acid Analysis of Urine Using the Hofmann Rearrangement
Authors: Kehl Horst
Published: January 2020

A method for the determination of hippuric acid in urine is described. The hippuric acid is converted to the N-bromobenzamide which can be quantitatively determined at 300 m µ. The conversion is a quantitative reaction.
Genetic and Molecular Basis of Human Hereditary Diseases
Authors: Seegmiller J Edwin
Published: January 2020

A fresh view of some old and new diseases recognized by means of modern genetics and biochemistry.
Method for the Determination of Acetylsalicylic Acid in the Blood
Authors: Routh J I , Shane N A , Arredondo E G , Paul W D
Published: January 2020

The shift in the UV spectral absorption curves of acetylsalicylic acid (ASA) and salicylic acid (SA) produced by a change in pH has been used in the development of a method for the quantitation of these compounds. The differential spectral absorption curve of ASA exhibits a maximum at 300 mµ, while that of SA shows a maximum at 319 mµ and an isosbestic point at 300 mµ. The method is simple and specific for ASA and capable of determining the concentration of the ASA and SA in the blood after the ingestion of 10 gr. of aspirin.
Comparison Between p-Nitrophenyl Glucuronide and Phenolphthalein Glucuronide as Substrates in the Assay of β-Glucuronidase
Authors: Szasz Gabor
Published: January 2020

The p-nitrophenyl glucuronide method for the determination of β-glucuronidase activity is compared with the phenolphthalein glucuronide method in a variety of diseases. It is shown that linear correlation exists between the two methods. The presence of isoenzymes, which would hydrolyze the substrates at different rates, is therefore excluded. The reaction conditions for the phenolphthalein glucuronide method are investigated and improved upon. Normal values for both methods in milliunits per milliliter are presented. The advantages of the p-nitrophenyl glucuronide method are indicated.
Fluorometric Determination of Zinc in Biologic Fluids
Authors: Mahanand D , Houck J C
Published: January 2020

The 8-quinolinol complexes of zinc at pH 8.0 (in universal buffer) are stabilized by gum arabic and demonstrate a marked fluorescence at 517 mµ when excited at 375 mµ. Under these conditions only zinc—not magnesium or calcium at physiologic concentrations—can be determined in plasma and urine. Adult plasma has 94 ± 7 µg. zinc per 100 ml. while the plasma of children contains 108 ± 15g./100 ml.
The Colorimetric Estimation of Plasma Amino Nitrogen with DNFB
Authors: Goodwin Jesse F
Published: January 2020

A simple procedure for the estimation of plasma amino nitrogen based on the reaction of amino groups with 2,4-dinitrofluorobenzene (DNFB) and subsequent measurement of the dinitrophenyl (DNP) amino derivatives at 420 mµ is presented. Elevated concentrations of bilirubin, hemoglobin, and the major nonprotein and nonamino acid nitrogen components of plasma do not seriously interfere. The proposed procedure compares favorably with a corresponding ninhydrin technic for plasma amino nitrogen. The mean plasma amino nitrogen values and range for a group of adults (age 18-50 years) by the proposed method is 5.56 mg./100 ml. (3.6-7.0 mg./100 ml.) compared to 4.12 mg./100 ml. (3.6-5.2 mg./100 ml.) for a group of children (age 2-10 years). Values from a group of children with sickle cell anemia showed no significant variance with the normal population. Optimum conditions for quantitation of plasma amino nitrogen along with other procedural parameters are presented.
One-Dimensional Paper Chromatographic Method for Determination of Urinary Homovanillic Acid
Authors: Duke Phillip S , Demopoulos Harry B
Published: January 2020

A one-dimensional paper chromatographic method is presented for determination of urinary homovanillic acid. The method is faster and gives higher values than does two-dimensional chromatography. Urinary homovanillic acid values are given for patients with metastatic malignant melanoma and for presumed normals. Homovanillic acid level was elevated in the case of amelanotic melanoma. Determinations of urinary homovanillic acid may be a valuable adjunct to the therapy and study of metastatic malignant melanoma.
Systematic Screening for Abnormal Urinary Constituents
Authors: Young D S
Published: January 2020

A scheme is described for the systematic screening for amino acids and sugars in urine. High-voltage electrophoresis is used to separate amino acids, and thin-layer chromatography is used for sugar separation. In each case the separated constituents are stained and scanned in a densitometer, and a profile is constructed for comparison against normal profiles.
Determination of Glutethimide (Doriden) and Its Metabolites in Biologic Specimens
Authors: Sunshine Irving , Maes Robert , Faracci Rosalie
Published: January 2020

A gas chromatographic method for the quantitative determination of glutethimide was developed. This method was applied to samples obtained from patients who were comatose because of acute glutethimide intoxication. The results obtained from this procedure were compared with those obtained by using an ultraviolet method. The patients’ clinical conditions were assessed and correlated with the blood concentrations of glutethimide. The samples were processed to isolate glutethimide, as well as its metabolites. The metabolites were separated using thin-layer chromatography and were checked for purity by both thin-layer and gas chromatography.
Stability of δ-Aminolevulinic Acid and Porphobilinogen in Urine Under Varying Conditions
Authors: Bossenmaier Irene , Cardinal Ruth
Published: January 2020

A study was made on the stability of δ-aminolevulinic acid and porphobilinogen in urine. Data are presented showing that both substances can be preserved in the same sample by adjusting the pH to 6-7 and storing at -20° for periods up to 1 month, or at 4° for periods up to 2 weeks. As previously shown (1), these conditions are also satisfactory for preservation of coproporphyrin.