bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal configuration of the energy storage system in ADN considering energy storage operation strategy and dynamic characteristic
Authors: Gong Qingwu , Wang Yubo , Fang Jintao , Qiao Hui , Liu Dong
Published: January 2020

To meet the needs of energy storage system configuration with distributed power supply and its operation in the active distribution network (ADN), establish the dynamics of the all‐vanadium redox flow battery energy storage system (BESS). On this basis, an energy storage operation of ADN strategy is proposed to stabilise the power fluctuation of the system. The energy storage configuration model with optimising objectives such as the fixed cost, operating cost, direct economic benefit and environmental benefit of the BESS in the life cycle of the energy is constructed, and the energy storage installation capacity, power and installation position are used as decision variables, which are solved by the dynamic programming algorithm. On the basis of case 33 and case 69 node examples and typical daily load and distributed generations output curve, the simulation analysis is carried out to obtain the optimal configuration result. At the same time, the system tie‐line power and the dynamic characteristics of the energy storage system before and after the installation of the energy storage device are obtained. The simulation results show the validity of the model.
Evaluation of cyber‐physical power systems in cascading failure: node vulnerability and systems connectivity
Authors: Chen Lei , Yue Dong , Dou Chunxia , Chen Jianbo , Cheng Zihao
Published: January 2020

In cyber‐physical power systems, tiny failure occurring in the communication network could propagate to affect the operation of the physical power grid through inter‐links and even cause catastrophic blackouts. The authors propose a partial random coupling systems model to study the vulnerability of nodes and connectivity of systems in a cascading failure. In terms of traffic loads generated in systems, they employ load spill index to analyse dynamic states of nodes in cascading failure. In cascading failure, considering the effect from a communication network, vulnerability matrices are established to study the vulnerability of nodes in the physical power grid. Furthermore, an efficiency index is defined to analyse connectivity of systems. In the numerical simulation, they verify the accuracy of the proposed evaluation approach and test its scalability and universality in different power systems.
Depth data and fusion of feature descriptors for static gesture recognition
Authors: Sharma Prachi , Anand Radhey Shyam
Published: January 2020

In this study, the authors propose a novel methodology for static gesture recognition in a complex background using only depth map from Microsoft's Kinect camera. Four different types of features are extracted and analysed on two public static gesture datasets. The features extracted from the segmented hand are geometrical, local binary patterns, number of fingers (Num) raised in a gesture and distance of hand palm centre from the fingertips and the valley between the fingers. The hand region is first segmented from the image using depth data followed by the forearm removal. Four multi‐class support vector machine (SVM) kernels are also compared and used for recognition of gestures with extracted feature vector as an input. The experimental results achieved recognition accuracy of 99 and on two public complex static gesture datasets using Gaussian SVM kernel function as a classifier. The proposed approach is found to be comparable and even outperforms some of the state‐of‐the‐art techniques in terms of high recognition accuracies, even after using a single cue for hand segmentation and extraction of features in the complex background which results in non‐dependency on too many cues and much hardware.
Investigation on space charge properties of Nomex insulation paper in the mining dry type transformer during hygrothermal ageing
Authors: Li Lu , Song Jiancheng , Wang Zhengyu , Zhang Rui , Cao Jinmei , Ma Yun , Li Yongzhi
Published: January 2020

Nomex insulation paper has been widely used in mining dry type transformer insulation because of its excellent performance. However, the injection of space charge can affect the electrical properties of the Nomex paper and accelerate the ageing process of the insulation system, which causes the insulation system failure or even breakdown. Therefore, it is of great practical value to study the space charge characteristics of Nomex insulation paper in different hygrothermal ageing conditions. The accelerated hygrothermal ageing tests of Nomex insulation specimens with different initial moisture contents were conducted. The space charge distribution of specimens impregnated by varnish were measured by the pulsed electro‐acoustic method at different ageing stages. Simultaneously, the space charge characteristics during polarising and depolarising phases were deeply analysed. Experimental results show that negative charges accumulate between the varnish‐paper interface in specimens near the anode. The number of negative charges gradually decreases with the increase of ageing degree. Under the influence of humidity, Nomex paper can be hydrolysed, which increases the trap density and trap level. Finally, a large amount of positive and negative charges in aged specimens would result in the distortion of the local electric field, which could decrease the breakdown strength of Nomex insulation specimens and be a threat to transformer insulation.
TCAD simulation of a double L‐shaped gate tunnel field‐effect transistor with a covered source–channel
Authors: Xie Haiwu , Liu Hongxia , Han Tao , Li Wei , Chen Shupeng , Wang Shulong
Published: January 2020

In this work, the authors propose and simulate a double L‐shaped gate tunnel field‐effect transistor (DLG‐TFET) with the covered source–channel. The proposed structure improves the ON‐state current by increasing the linear tunnelling area and has excellent subthreshold characteristics. The simulation focuses on the performance improvement of the device under different longitudinal gate length Lg, interlayer silicon thickness Tsi, gate and source overlap length Lov, and covered source depth Ls. For optimal parameters, the ON‐state current of the proposed DLG‐TFET increases up to 3.53 × 10−5 A/μm, and the current switch ratio(Ion/Ioff) is 4.28 × 1011 at room temperature, moreover, a minimum subthreshold swing (SSmin) and an average subthreshold swing (SSave) are as low as 32.2 and 52.9 mV/Dec, respectively. Meanwhile, this work uses mixed device‐circuit simulations to predict the performance of the inverter circuit implemented with proposed DLG‐TFET.
Implementation of ∑Δ ADC using electrically doped III‐V ternary alloy semiconductor nano‐wire TFET
Authors: Rajan Chithraja , Patel Jyoti , Sharma Dheeraj , Behera Amit Kumar , Lodhi Anil , Lemtur Alemienla , Samajdar Dip Prakash
Published: January 2020

In this work, a fast and low‐power sigma delta analogue‐to‐digital converter (ADC) has been developed using a hetero‐material electrically‐doped nano‐wire tunnel field effect transistor (HM‐ED‐NW‐TFET) for the first time. The better gate controllability of nano‐wire and immunity against process variations of electrically doped tunnel field effect transistor (TFET) enhances resolution. In this regard, the first step that has been performed is the material engineering using , to achieve significant driving current at low subthreshold swing and high ratio. Secondly, the mole fraction is optimised to upgrade the critical analogue component – the op‐amp. Also, drain under lapping is included in p‐TFET to bring its characteristics as close to n‐TFET. Latter, the look‐up tables of the proposed device has been generated which is used to develop individual block of ADC in Cadence. The blocks are well verified and integrated into final ADC and its performance is evaluated. Hence, this work has explored the inherent merits of HM‐ED‐NW‐TFET in the development of low power and fast ADC by virtue of a high slew rate op‐amp. Therefore, this work contributes a novel approach to explore the characteristics of emerging devices in mixed signal applications.
A first attempt to differentiate between modified gravity and modified inertia with galaxy rotation curves
Authors: Petersen Jonas , Lelli Federico
Published: January 2020

The phenomenology of modified Newtonian dynamics (MOND) on galaxy scales may point to more fundamental theories of either modified gravity (MG) or modified inertia (MI). In this paper, we test the applicability of the global deep-MOND parameter Q which is predicted to vary at the 10% level between MG and MI theories. Using mock-observed analytical models of disk galaxies, we investigate several observational uncertainties, establish a set of quality requirements for actual galaxies, and derive systematic corrections in the determination of Q. Implementing our quality requirements to the SPARC database yields 15 galaxies, which are close enough to the deep-MOND regime as well as having rotation curves that are sufficiently extended and sampled. For these galaxies, the average and median values of Q seem to favor MG theories, albeit both MG and MI predictions are in agreement with the data within 1.5σ. Improved precision in the determination of Q can be obtained by measuring extended and finely-sampled rotation curves for a significant sample of extremely low-surface-brightness galaxies.
Synthesis of Novel 1,2,3-Triazole-Dihydropyrimidinone Hybrids Using Multicomponent 1,3-Dipolar Cycloaddition (Click)–Biginelli Reactions: Anticancer Activity
Authors: Carreiro Elisabete P. , Sena Ana M. , Puerta Adrián , Padrón José M. , Burke Anthony J.
Published: January 2020

In this work, 21 novel (1,4-disubstituted 1,2,3-triazole)-dihydropyrimidinone (1,2,3-trzl-DHPM) type hybrids were synthesized and characterized. These were divided into two types: hybrids A (5 in total) containing the dihydropyrimidinone heterocyclic ring decorated with a 1,4-disubstituted 1,2,3-triazole in the C-5 position [these compounds were accessed by a multicomponent copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) (or click)–Biginelli reactions with satisfactory yields (39–57%)] and hybrids B (16 in total) containing two 1,2,3-triazole units in the C-5 and C-6 methyl position of the DHPM. Hybrids B were synthesized via functionalization of the C-6 methyl group of hybrids A, a multistep sequence of reactions was used that included bromination, azidation, and a CuAAC. Hybrids B were obtained in very good to excellent yields (up to 99%). Some hybrids A and B were evaluated for their antiproliferative activity against different cancer cell lines that included A549 and SW1573 (non-small-cell lung), HBL-100 and T-47D (breast), HeLa (cervix) and WiDr (colon). Three of these hybrids were potent cell proliferation inhibitors of non-small-cell lung cancer, cervix cancer, breast cancer, and colon cancer.
Photo-Biocatalytic Cascades for the Synthesis of Volatile Sulfur Compounds and Chemical Building Blocks
Authors: Castagnolo Daniele , Lauder Kate
Published: January 2020

Biocatalysis is a branch of catalysis that exploits enzymes to perform highly stereoselective chemical transformations under mild and sustainable conditions. This Synpact highlights how biocatalysis can be used in the synthesis of chiral 1,3-mercaptoalkanols, an important class of compounds responsible for the flavours and aromas of many foods and beverages. The identification of two ketoreductase (KRED) enzymes able to reduce prochiral ketone precursors enantioselectively to 1,3-mercaptoalkanols bearing a C–O stereocentre is presented. In addition, the combination of a photocatalytic thia-Michael reaction to access prochiral ketones with subsequent KRED-biocatalysed reduction in a one-pot cascade is presented. Photo-biocatalysed cascades represent one of the new and most intriguing challenges in synthetic chemistry, because the combination of different catalytic methodologies in domino processes offers unique opportunities to outperform sequential reactions with a high degree of selectivity and the avoidance of the need to isolate reaction intermediates.

1 Introduction

2 Biocatalytic Synthesis of 1,3-Mercaptoalkanols

3 Photo-Biocatalytic Synthesis of 1,3-Mercaptoalkanols

4 Photo-Biocatalysed Cascade Reactions

5 Conclusions
An Efficient Palladium-Catalysed Aminocarbonylation of Benzyl Chlorides
Authors: Richardson Jeffery , Rilvin-Derrick Eloise , Oram Niall
Published: January 2020

An improved procedure for the aminocarbonylation of benzyl chloride derivatives using carbon monoxide and either primary or secondary amines has been developed. Studying the competing background alkylation reaction allowed the solvent and base to be selected for a simple catalyst screen, which, in turn, enabled the discovery of a method for the preparation of 2-arylacetamides under mild conditions, with minimal side-products using an inexpensive phosphine ligand. This non-traditional optimisation strategy allowed us to overcome the background alkylation, which has been cited as justification for the development of more complex and less atom-economical approaches.
Uniform spheroid formation on a laboratory-made, low cell attachment surface consisting of a chitin sheet
Authors: Inubushi Yusaku , Tachibana Akira
Published: January 2020

We utilized the reaction of chitosan with acetic anhydride to form a chitin gel. This gel was then dried, which formed a chitin sheet. The procedure was extremely easy for a biologist unfamiliar with materials engineering. Spheroids derived from HEK293T cells were formed on the chitin sheet, because the spheroids slightly attached and slowly moved on the chitin sheet.
The feeding preference of sunda scops-owl (Otus lempiji horsfield) to bait
Authors: Aswari R L , Priyambodo S
Published: January 2020

Oil palm is the most important plantation commodities in Indonesia due to planting area and productivity. There are some constrains faced by oil palm management, one of them is plant pest including insects and rats. Insects and rats have a high reproduction capability and severely damage to oil palm plantation. An effective and environmentally control of these pests using natural enemies, one of them owl. The sunda scops-owl (Otus lempiji Horsfield) was tested in the Laboratory of Vertebrate Pest, IPB University using different types of feed, to calculate the level of bait preference. Method used was bi-choice test, comparing the feeding of preference bait between: (a) rat and larvae of beetle, (b) rat and lizard, (c) rat and fish, (d) rat and cricket. Before and after treatment, all baits were weighed to determine the amount consumption and preference to feed. The data showed that the sunda scops-owl consumed rat higher than larvae of beetle, lizard, fish, and cricket, and significantly different.
Proposed parameter for the characterization of friction in cylindrical gears teeth contact
Authors: Alaci S , Bujoreanu C , Petrea N D , Ciornei F C , Irimescu L
Published: January 2020

Gear mechanisms are widely used in technical applications, mainly for transmitting rotational motion between two axes with constant transmission ratio via a higher pair. Significant friction energy loss in the pair between teeth highlights the importance of estimating the mechanical work lost by friction within this contact. In a previous study, the coefficient of rolling friction between a cylindrical body and a flat face body was found based on the decrease of oscillations amplitude of a cycloidal pendulum. The basic idea of the present paper follows the observation that in the case of a gear mechanism, the relative motion between the wheels can be taken as relative motion of their axodes. In this regard, a pendulum obtained from a mobile cylindrical gear with attached rod and a fixed corresponding rack is considered. The law of motion of the cycloidal pendulum is applied for the proposed pendulum and an “equivalent rolling friction coefficient” which characterises the friction between the teeth of the pinion and the rack is found. The differential equation modelling the motion of the pinion-rack pendulum is difficult to obtain, which is explained by the analysis of the involute gear field of a general cylindrical gear mechanism.
Preliminary theoretical results of limited slip couplings
Authors: Gatu V , Predescu A , Stoicescu A I
Published: January 2020

Limited slip couplings are a solution for the traction of an all-wheel drive vehicle. The limited slip coupling can be mounted between the front and rear differentials for torque distribution, but also on a front or rear axle to distribute torque between two wheels Theoretical analysis is performed with a software plug-in with computed fluid dynamics. One of the most important features of a four wheel drive system is the control of the torque transmitted to the wheels. In order to get as much power as possible to the ground, the torque has to be divided among the four wheels to minimize the wheel spin. The limited slip coupling deals with this problem in a new, and, from many points a view, better way. The coupling can be compared to a hydraulic piston pump, which is driven by the slip between input and output shafts. The oil flow from the pump results in an oil pressure that is controlled by a throttle valve. The oil pressure compresses a wet multi-plate clutch that derivers torque to the output shaft. The torque on the output shaft is proportional to the oil pressure. Without the throttle valve the coupling would transfer the torque whenever there is differential rotational speed between the two shafts. One of the objectives of this paper is to present the importance of using CAD and CFD programs and to simulate the behavior of the coupling introducing a momentum, an energy and the material used for the disks, and to obtain results for heat flux and temperature.
Preliminary study of friction in automotive ball joints
Authors: Muscă I , Românu I C , Gagea A
Published: January 2020

The present paper offers a brief description of the testing equipment, experimental methodology and some results regarding the motion resistive effort in automotive ball joints. The local ball joints manufacturers have difficulties in controlling the clamping force of the ball joints in the production process. Due to this, an original experimental device was conceived and built in order to evaluate the magnitude and evolution of internal friction between the joint’s surfaces. The experimental setup’s main advantage is the capacity of controlling and maintaining a constant clamping force and that it ensures a constant motion of the ball stud. The force magnitude was recorded using resistive transducers connected to a data acquisition system. The numerical values were recorded and used to analyse the mobility of the tested ball joints.
Surface roughness influence on active surfaces geometry and modified rating life of rolling contacts
Authors: Benchea M , Creţu S
Published: January 2020

The active surfaces topography of bodies in rolling contact can be obtained by different manufacturing technology. The scope of this paper is to evidence the influence of the initial surface roughness on running-in process, working surface geometry and durability of rolling contacts. The paper presents a numerical study applied on a toroidal roller bearing where the modified rating lives have been evaluated with the methodologies mentioned by ISO 16281.
Fractal evaluation aspects in characterizing the roughness of a driving wheel from a locomotive
Authors: Babici L. , Tudor A. , Romeu Garbi J. , Stoica M.
Published: January 2020

For comprehending tribological phenomena such as wear, friction, contact deformation and tightness of contact joints is the essential characterisation of the multiple scale topography of roughness surfaces. Wheel roughness obtained through direct measurement and then a description of wheel roughness has been obtained using the fractal function. The statistical parameters and fractal sizes for drive wheels which ran 2000 km and another ones new wheels have been analysed.By registering the results and programmable automaton of the roughness, the principal statistical characteristics were determined to be stands out the Abbott-Firestone curve and respectively, the fractal character. The appearance of roughness on the surface of the wheel causes the production of vertical vibrations that act on the complex wheel-rail system.In the analysis of the wheel irregularity, the fractal geometry was applied, so that to obtain the fractal parameters Dw, respectively Ltw (opothesy length), the method of the structure function was used [1, 2]. Therefore, the experimental measurement and obtained results processed presented.
An Experimental Approach to Predict the Behaviour of EHD Contacts under Harmonic Loading
Authors: Zhang X , Glovnea R
Published: January 2020

Rolling element bearings, gears and other machine components operate in the lubrication regime known as elastohydrodynamic (EHD), where lubricant film thickness is governed by the hydrodynamic action of the converging surfaces, the elastic deformation of the non-conforming surfaces and the increase of lubricant’s viscosity with pressure. Classic EHD theory indicates that under the assumption of fully flooded conditions in the contact inlet zone the central film thickness increases with the product of entrainment speed and dynamic viscosity and is very little dependent of load variations. EHD lubricating films most often work under transient conditions of load, geometry or speed. These make the behaviour of the lubricant film different from steady-state conditions. Previous studies showed that the squeeze effect generates film perturbations due to entrapment of lubricant inside the contact. This phenomenon becomes significant when both entrainment and squeeze are presented. In practical applications, this type of film perturbation will generate pressure fluctuations, which in turn may influences the fatigue life of the contact. In the present paper the results of a systematic experimental study for predicting the occurrence of film thickness perturbation phenomenon under variable load condition are shown. In the case of a mean load larger than the amplitude of the load variation, it was found that the film perturbation depends of the frequency of the load cycle, the entrainment speed of the lubricant and the overall lubricant film thickness; it also depends of the ratios between the mean load and the amplitude. Film perturbations occur in contacts for which the ratio between half the load cycle period and the average time of transit of the lubricant through the contact in the loading phase of the vibration is less than 2. In the case of mean load smaller than the amplitude, film thickness perturbation has been observed in every single test regardless of entrainment speed, frequency and lubricant viscosity.
Tribological behavior of rapeseed oil additivated with boron nitride
Authors: Guglea D , Ionescu T F , Dima D , Georgescu C , Deleanu L
Published: January 2020

This paper presents results of testing the coarse rapeseed oil additivated with 1%wt hexagonal boron nitride (hBN). Tests are done on a four-ball machine from the laboratory LubriTest, at “Dunarea de Jos” University of Galati. Tests were done in mild regime (recommended for applications) and in severe regime. The mild test parameters were: load on the main shaft of the machine (100 N, 200 N and 300 N) and the sliding speed of 0.38 m/s, 0.53 m/s and 0.69 m/s, test duration 1 h. Severe test were run in step of 50 N till 900 N, each test being run for 1 minute at 0.53 m/s. The concentration of 1%wt hBN does not improve the friction coefficient, but it makes it stable for a larger domain of test parameters. The wear rate of wear scar diameter was lower than that obtained with the base oil, especially for high loads. Also, the paper presents the influence of the additive on the temperature of oil bath and the wear load curve of the neat oil and the additivated one. The additivation of rapeseed oil with hNB is still efficient for the tested ranges of load as compared to the rapeseed oil. The load-wear curve for the severe regime points out a sudden increase of wear scar diameter (WSD) for the rapeseed oil +1% hNB at 700 N, but the neat vegetal oil starts the increase of WSD at 550 N, followed by a greater slope, meaning the additive protect the rubbing surfaces under these high loads.
Direct and Indirect Relationships Between the Built Environment and Individual-Level Perceptions of Physical Activity: A Systematic Review
Authors: Rhodes Ryan E , Zhang Ru , Zhang Chun-Qing
Published: January 2020

Background

Socioecological models highlight the potential direct and indirect effects of multiple levels of influence in explaining physical activity (PA). Social cognitive theories, however, position individual cognitions as the mediator of external factors such as the built environment when explaining PA.

Purpose

To appraise the evidence for direct and indirect associations between the built environment and social cognition to predict PA.

Methods

Literature searches were concluded in February 2019 using five common databases. Eligible studies were in the English language that included any direct and indirect tests of individual perceptions and the built environment with PA.

Results

The initial search yielded 18,521 hits, which was reduced to 46 independent studies of primarily medium quality after screening for eligibility criteria. Findings were grouped by type of PA then grouped by the type of individual and built environment constructs within the model, and subdivided by adult and youth samples. There was evidence that self-efficacy/perceived control accounted for the covariance between environmental accessibility/convenience and total PA, while habit accounted for the covariance in this relationship for transport PA, particularly in adult samples. There was no evidence that the built environment had a direct association with PA after controlling for individual-level factors.

Conclusions

The results provide initial support for the mediation tenet in social cognition models for the relationship between individual, built environment, and PA. In practice, these findings highlight the need for coordinated interventions of individual and environmental change.
Characteristics and Outcomes of Patients Presenting With Hypertensive Urgency in the Office Setting: The Campania Salute Network
Authors: Mancusi Costantino , Losi Maria Angela , Albano Giovanni , De Stefano Giuliano , Morisco Carmine , Barbato Emanuele , Trimarco Bruno , De Luca Nicola , de Simone Giovanni , Izzo Raffaele
Published: January 2020

BACKGROUND

Hypertensive urgencies (HypUrg) are defined as severe elevation in blood pressure (BP) without acute target organ damage. In the office setting, treated asymptomatic patients, with severe BP elevation meeting criteria for urgency are often seen. We evaluate incident Cardiovascular (CV) events (n = 311) during follow-up (FU) in patients with HypUrg at first outpatient visit.

METHODS

HypUrg was defined by systolic BP ≥180 mm Hg and/or diastolic BP ≥110 mm Hg. Patients were >18 years old, with available ultrasound data, without prevalent CV disease, and no more than stage III Chronic Kidney Disease. BP control was defined as the average BP during FU <140/90 mm Hg.

RESULTS

Four hundred and sixty-nine of 6,929 patients presented with HypUrg at first visit. Patients with HypUrg were more likely to be women, obese and diabetic and with higher prevalence of left ventricle (LV) hypertrophy and carotid plaque (all P <  0.05). During FU patients with HypUrg had 5-fold higher risk of uncontrolled BP (95% confidence interval (CI) 4.1–6.8, P < 0.0001). In Cox regression presenting with HypUrg was not associated with increased CV risk after adjusting for significant covariates, including age, sex, BP control, LV hypertrophy, and carotid plaque (hazard ratio (HR) 1.42, 95% CI (0.96–2.11), P = 0.08).

CONCLUSIONS

Patients with HypUrg have worst CV risk profile, reduced probability of BP control during FU and greater prevalence of target organ damage, but the excess CV event risk appears to be mediated through BP control, non-BP cardio-vascular disease risk factors, and demographic attributes.

CLINICALTRIALS.GOV IDENTIFIER

NCT02211365.
Serious Adverse Events Cluster in Participants Experiencing the Primary Composite Cardiovascular Endpoint: A Post Hoc Analysis of the SPRINT Trial
Authors: Botchway Albert , Buhnerkempe Michael G , Prakash Vivek , Al-Akchar Mohammad , Adekola Bemi , Flack John M
Published: January 2020

BACKGROUND

Intensively treated participants in the SPRINT study experienced fewer primary cardiovascular composite study endpoints (CVD events) and lower mortality, although 38% of participants experienced a serious adverse event (SAE). The relationship of SAEs with CVD events is unknown.

METHODS

CVD events were defined as either myocardial infarction, acute coronary syndrome, decompensated heart failure, stroke, or death from cardiovascular causes. Cox models were utilized to understand the occurrence of SAEs with CVD events according to baseline atherosclerotic cardiovascular disease (ASCVD) risk.

RESULTS

SAEs occurred in 96% of those experiencing a CVD event but only in 34% (P < 0.001) of those not experiencing a CVD event. Occurrence of SAEs monotonically increased across the range of baseline ASCVD risk being approximately twice as great in the highest compared with the lowest risk category. SAE occurrence was strongly associated with ASCVD risk but was similar within risk groups across treatment arms. In adjusted Cox models, experiencing a CVD event was the strongest predictor of SAEs in all risk groups. By the end of year 1, the hazard ratios for the low, middle, and high ASCVD risk tertiles, and baseline clinical CVD group were 2.56 (95% CI = 1.39–4.71); 2.52 (1.63–3.89); 3.61 (2.79–4.68); 1.86 (1.37–2.54), respectively—a trend observed in subsequent years until study end. Intensive treatment independently predicted SAEs only in the second ASVCD risk tertile.

CONCLUSIONS

The occurrence of SAEs is multifactorial and mostly related to prerandomization patient characteristics, most prominently ASCVD risk, which, in turn, relates to in-study CVD events.
Mass concentration and activity concentration of creatine kinase isoenzyme MB compared in serum after acute myocardial infarction
Authors: Delanghe J R , De Mol A M , De Buyzere M L , De Scheerder I K , Wieme R J
Published: January 2020

We compared three current methods (immunoinhibition, "Isomune-CK" immunoprecipitation, and the Tandem-E CKMB II immunoenzymometric assay) for determination of creatine kinase (CK; EC 2.7.3.2) isoenzyme MB in serum. Although results inter-correlated well, the immunoinhibition assay gave higher activity values. Atypical CK forms did not interfere with the immunoprecipitation and immunoenzymometric methods. In acute myocardial infarction the catalytic properties of CK decreased with the enzyme's age, as reflected by a steady increase in activation energy of the catalyzed reaction. In septicemia patients with very low CK and CK-MB catalytic activity, mean CK-MB mass concentration exceeded the upper reference limit, suggesting an increased rate of loss of activity concentration in these patients' sera. Because of the assay's lesser susceptibility to conformational changes at the active site of the enzyme, we suggest that measurement of CK-MB mass concentration is better suited for infarct sizing than measurement of catalytic activity.
Monoclonal antibody inhibiting creatine kinase MM3 but not isoform MM1
Authors: Suzuki T , Shiraishi T , Tomita K , Totani M , Murachi T
Published: January 2020

Monoclonal antibody CKM-G01 inhibited greater than 99% of the activity of porcine and human creatine kinase(CK)-MM isoenzyme purified from muscle. However, it inhibited only 54% of CK-MM in human serum. Chromatofocusing of serum CK-MM showed that CKM-G01 inhibited 100% of MM3 but not isoform MM1. CKM-G01 inhibited CK-MM2 by 57%. CKM-G01 specifically inhibited only the original CK-M subunit and not the subunit modified by removal of C-terminal lysine by carboxypeptidase N. CKM-G01 can be used for assay of CK isoforms. We devised a new diagnostic reagent involving it, which requires no analytical separation of isoforms, based on the immunoinhibition method, and applied it to early diagnosis of acute myocardial infarction. The "inhibition index," (inhibited CK activity/total CK activity) x 100, increased more rapidly than did total CK and CK-MB. Evidently this diagnostic reagent can be used for easy, early diagnosis of acute myocardial infarction.
Rapid enzymatic analysis of plasma for tyrosine
Authors: Shimizu H , Taniguchi K , Sugiyama M , Kanno T
Published: January 2020

In this rapid, simple, and convenient enzymatic method for measurement of tyrosine in plasma, tyrosine is converted to tyramine by action of tyrosine decarboxylase (EC 4.1.1.25) and the tyramine produced is oxidized to p-hydroxybenzyl aldehyde and hydrogen peroxide by action of tyramine oxidase (EC 1.4.3.9). The hydrogen peroxide is reacted with 4-aminoantipyrine and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine in the presence of peroxidase (EC 1.11.1.7) to obtain quinoneimine dye, the absorbance of which is measured at 570 nm. Thus tyrosine is measured in the visible range. The CV was 4.6% or less, and the measurement was unaffected by other amino acids, except for phenylalanine. The values obtained (y) correlated well with those obtained with an amino acid analyzer (x): y = 0.902x + 3.92 mumol/L (Syx = 12.3; r = 0.985; n = 54).
Quantitative immunoenzymatic assay of human lutropin, with use of a bi-specific monoclonal antibody
Authors: Bugari G , Poiesi C , Beretta A , Ghielmi S , Albertini A
Published: January 2020

In this immunoenzymatic assay for human lutropin (hLH) we used bi-specific antibodies (BiAbs) obtained from the fusion of two hybridomas producing antibodies to beta-D-galactosidase and hLh. The BiAb complexed with the enzyme beta-D-galactosidase was used as tracer in a double-determinant assay. We compared the assay involving the BiAb (Bi-EIA) with an immunoenzymatic assay (EIA) in which the same capture antibody was used but the tracer was an enzyme-conjugated hLH-specific monoclonal antibody produced by the same parental cell line used to produce the BiAb. The coefficient of correlation (r) between the two assays was 0.979 but the Bi-EIA was more sensitive (detection limits: 0.8 int. units/L for the Bi-EIA, 2.0 int. units/L for the EIA) and more specific (less than 0.04% vs less than 1.2% cross-reactions with human choriogonadotropin). Mean intra- and interassay CVs for the Bi-EIA were 2.9% and 5.9%, respectively. Correlation (r) with an immunoradiometric assay (IRMA, Serono kit) was 0.960, with radioimmunoassay (RIA, Biodata kit) 0.909, and with an enzyme-linked immunosorbent assay (ELISA kit, Specialty Medical Industries Inc.) 0.888, (n = 25). Evidently, bi-specific antibodies can be used successfully in immunoenzymatic assays, and with potentially greater sensitivity and specificity than assay with a traditional antibody-enzyme conjugate.
1990 Medicare/CLIA final rules for proficiency testing: minimum intralaboratory performance characteristics (CV and bias) needed to pass
Authors: Ehrmeyer S S , Laessig R H , Leinweber J E , Oryall J J
Published: January 2020

On March 14, 1990, the Centers for Disease Control and the Health Care Financing Administration published criteria for defining minimum performance in proficiency testing (PT). Using our previously described computer modeling technique, we determined the likelihood of passing PT under the new rules. The model relates combinations of intralaboratory CV and bias to PT performance criteria. For example, a laboratory with a bias of zero and an internal CV of 5% will pass a 10% fixed-limit PT criterion (i.e., the criterion for glucose analyses) 98% of the time when five samples are used. The model provides similar analyses for all PT criteria and all relevant combinations of CV and bias. The probability of passing PT decreases as the number of analytes tested increases, i.e., from 98% to 37% as the number of analytes increases from 1 to 20. A laboratory's internal CV has a greater effect on the outcome of PT than do the corresponding bias values. We conclude that a laboratory that operates with methods that have internal CVs less than or equal to 33% and biases less than or equal to 20% of the PT criteria will have a greater than 99% chance of passing PT.
Mass concentration of creatine kinase MB isoenzyme and lactate dehydrogenase isoenzyme 1 in diagnosis of perioperative myocardial infarction after coronary bypass surgery
Authors: Gulbis B , Unger P , Lenaers A , Desmet J M , Ooms H A
Published: January 2020

Recent advances in methodology allow the mass concentration of creatine kinase MB isoenzyme (CK-MB), and of lactate dehydrogenase isoenzyme 1 (LD1) to be determined quickly and easily as routine, emergency tests. We evaluated these tests as diagnostic criteria of perioperative myocardial infarction (PMI) after coronary bypass surgery. These tests were compared with the usual measurements of CK-MB activity by immunoinhibition and LD1 by electrophoresis and with other biological markers of myocardial infarction such as total CK, total LD, and aspartate aminotransferase. Sixty-one patients who underwent coronary bypass grafting were followed pre- and postoperatively by enzyme determinations and electrocardiography; a subgroup was monitored by myocardial scintigraphy. CK-MB mass appeared to be the best marker of PMI during the first 48 h, although LD1 was the marker of choice from days 2 to 4.
Automated fructosamine assay with improved accuracy used to quantify nonenzymatic glycation of serum proteins in diabetes mellitus and chronic renal failure
Authors: Taş S , Zein el Din R R
Published: January 2020

We optimally solubilized the diformazan that forms during the fructosamine reaction with a nonionic detergent; we then automated the assay. After optimal solubilization of diformazan, we found that serum urate contributed significantly to the color formation in fructosamine reaction. When the error introduced by urate was corrected mathematically by use of an experimental determined factor, the serum fructosamine concentrations obtained were comparable with those of a more specific test of the nonenzymatic glycation (HPLC of hydrolyzed proteins). We found that concentrations of fructosamine in serum increased with increasing age of subjects. In diabetic patients the average concentration of fructosamine in serum exceeded that in nondiabetic subjects and correlated with the preprandial serum glucose and with other measures of deteriorating glycemic control (e.g., increased need for insulin therapy). Serum fructosamine normalized for albumin content was also increased in patients with chronic renal failure. Multiple mechanisms (including exposure of patients to hypertonic glucose during dialysis) appear to be involved in the increase of serum fructosamine in patients with chronic renal failure.
Anomalous serum thyroxin measurements with the Abbott TDx procedure
Authors: Levine S , Noth R , Loo A , Chopra I J , Klee G G
Published: January 2020

We describe a patient whose serum gave consistently low results for thyroxin as measured with the Abbott TDx but normal results by radioimmunoassay. Further clinical and laboratory studies did not support the low TDx results. Anti-thyroxin antibodies did not explain the discordant results, and we found no evidence of heterophilic antibodies in the patient's serum. We were unable to identify the cause of the problem.
Quantitative and functional assays compared for determination of zymogen and activated human protein C
Authors: Richards S M , Olson T , Keyes L D
Published: January 2020

We evaluated quantitative and functional assays for protein C, using either purified protein C samples or pooled normal plasma as assay standards. The purified protein C samples were examined as the zymogen form and after activation by thrombin. Mass concentrations of protein C were determined by amino acid analysis and confirmed by enzyme-linked immunosorbent assay (ELISA). Functional activity was assessed in both standard clot inhibition and amidolytic assays. The accuracy and precision of the ELISA was acceptable, with all three preparations of protein C having similar linear curves. The clot inhibition assay demonstrated marked variability when used according to the manufacturer's instructions; however, modifications to the protocol significantly decreased the CV, to less than 10%. Both activated protein C and the zymogen gave linear standard curves. Pooled normal human plasma gave a nonlinear curve, which contributed to inaccurate sample recoveries. We obtained the most nearly accurate recoveries when we used activated protein C as the assay standard. Amidolytic assays provided no insights into the appropriateness of the preparations for that assay format. A uniform, consistent source of protein C, e.g., recombinant activated protein C, would be useful for standardizing all assays of protein C.
Diet-related reference values for plasma amino acids in newborns measured by reversed-phase HPLC
Authors: Scott P H , Sandham S , Balmer S E , Wharton B A
Published: January 2020

We have measured by reversed-phase HPLC concentrations of amino acids in plasma in groups of 80 normal appropriate-weight term babies fed from birth either a casein formula (WhiteCap SMA, n = 26), a whey formula (Gold Cap SMA, n = 26), or breast milk (n = 28). They were studied from day 11 to week 15 postpartum. The trend was towards an increase in amino acid concentrations in plasma with age, more marked in formula-fed than in breast-fed infants. Reference values were derived for each group. Both formula-fed groups showed several differences from the breast-fed group. Detailed examination indicated that tyrosine, phenylalanine, and methionine concentrations were increased in the casein-fed group greater than 20% of the time, but only threonine was similarly increased in the whey-fed group. Other amino acids, different ones for each formula group, were increased less frequently. There were no consistent correlations with any aspect of infant growth. Appropriate reference values are important for interpreting amino acid concentrations in plasma from newborns and for evaluating the effects of any future dietary modifications to infant formulas. HPLC analysis provides a suitable highly sensitive method for undertaking such studies.
Ultrasensitive two-site immunometric assay of human lutropin by time-resolved fluorometry
Authors: Pettersson K S , Söderholm J R
Published: January 2020

A rapid, sensitive two-site immunometric assay for human lutropin (LH), with two monoclonal antibodies directed against the beta subunit, has been developed with time-resolved fluorescence as the detection principle. The cross-reactivities with human thyrotropin and human follitropin are negligible and that with human choriogonadotropin is 1% in the standard two-step protocol. Free beta subunits of LH are also detected. Besides the standard procedure (45 + 15 min), more rapid alternative protocols (15 + 15 min or 30 min in one step) have also been evaluated. The minimum detectable dose per well is approximately 1 amol (10(-18) mol), corresponding to less than 0.01 int. unit/L, for a sample volume of 25 microL and less than 0.001 int. unit/L for 200-microL samples. The intra- and interassay CV is less than 6% for LH concentrations from 0.2 to 250 int. units/L. With 200-microL sample volumes, intra-assay variation is less than 6% at 0.04 int. unit/L and interassay variation is 7% at 0.05 int. unit/L. The very high sensitivity and reproducibility of the presented method enables assay of low prepubertal and of suppressed LH concentrations, and represents a clear improvement over currently available immunoassays.
Particulate (high-molecular-mass) and soluble alkaline phosphatase in urine determined by high-performance liquid chromatography
Authors: Schoenau E , Herzog K H , Michalk D
Published: January 2020

We detected in urine by HPLC two enzyme fractions of alkaline phosphatase (AP, EC 3.1.3.1), soluble and particulate, analogous to those in serum. The second fraction was eluted with high-salt-content eluent at the same elution time as high-molecular-mass, or particulate, AP in serum. AP characterization in urine from a patient with acute rejection crisis showed a greater sensitivity of the particulate form to treatment with L-phenylalanine, which suggests a higher content of intestinal-type AP in the particulate form. The soluble fraction showed a more liver-type AP behavior. Changes in the chromatograms after the sample was treated with 1-butanol and Triton X-100 support a membrane origin of the particulate AP. Urinalyses from patients with acute renal disease showed increased activity of soluble and particulate AP, with a relatively greater increase of particulate AP.
Enzymatic method for selective determination of 4-aminobenzoic acid in urine
Authors: Bando N , Ogawa T , Tsuji H , Sasaoka K
Published: January 2020

We developed a method for the selective determination of 4-aminobenzoic acid by use of 4-aminobenzoate hydroxylase (EC 1.14.13.27) to convert 4-aminobenzoic acid to 4-hydroxyaniline. The subsequent conversion of 4-hydroxyaniline to indophenol dye was quantified colorimetrically. The method is reproducible, and the assay response is linear up to 40 mumol/L. Selectivity exceeding that of the current colorimetric assays was demonstrated for these enzymatic determinations of 4-aminobenzoic acid concentrations in urine samples from patients undergoing tests of pancreatic function with bentiromide. This method effectively minimizes interferences from drugs and diet, a problem in current colorimetric methods.
Candidate reference method for determining creatinine in serum: method development and interlaboratory validation
Authors: Rosano T G , Ambrose R T , Wu A H , Swift T A , Yadegari P
Published: January 2020

We describe a "high-performance" liquid chromatographic (HPLC) method for accurately determining creatinine in serum. After prechromatographic precipitation of protein, we performed isocratic ion-exchange chromatography with ultraviolet detection (234 nm). Analytical results showed linearity up to 1770 mumol/L, a detection limit of 22 mumol/L, an average analytical recovery of 101%, and a CV ranging from 3% to 11%. We used certified human serum (National Institute of Standards and Technology), and additional lyophilized serum pools also assayed by definitive isotope-dilution mass spectrometry, to validate the accuracy of the HPLC method. In addition, the isocratic HPLC results showed close agreement with those obtained with a step-gradient HPLC method. We also compared the isocratic HPLC method with alkaline picrate and enzymatic methods. Our findings with samples from nonuremic, uremic, and diabetic ketoacidotic patients confirmed the positive bias previously reported with the alkaline picrate method. Interlaboratory transferability of the method was demonstrated with various commercial instruments and analytical columns. We evaluated column stability and possible interference from endogenous or exogenous compounds. On the basis of our analytical findings, we recommend the isocratic HPLC method as a candidate Reference Method for determining creatinine in serum.
Simple screening tests for the emergency identification of methanol and ethylene glycol in poisoned patients
Authors: Jarvie D R , Simpson D
Published: January 2020

We have developed simple and rapid screening tests for methanol and ethylene glycol in plasma of poisoned patients, based on the Toxi-Lab alcohol screening test. The compounds are first converted to formaldehyde, which diffuses from the patient's sample into a glass-fiber test sheet impregnated with Schiff's formaldehyde detection reagent. Subsequent exposure of the test sheet to acid and heat distinguishes formaldehyde from acetaldehyde. We recommend that samples giving positive results be analyzed by another technique to confirm the identity and concentration of the poison for use in prognosis and treatment.