bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison between IGBTs and Diode Converters for DC Railway Electrification Systems
Authors: Li Zijian , Yang Minlong , Tricoli Pietro
Published: July 2020

This paper describes a comparison between the specific DC railway models with insulted gate bipolar transistors rectifiers and diode rectifiers. As silicon diode was applied to railway electrification system decades ago, the IGBTs rectifiers have not obtained wide application yet. In this research, the performance of these rectifiers is presented and analysed. The power supply to the load, system losses and effects to systems are the main aspects compared in this paper. The analysis presents the possibility that new types of power converters can be adapted in DC railway electrification system. The simulations are carried out with MATLAB and Simulink.
Experiments and simulation analysis of 500kV single-phase three-column transformer in No-load under DC bias
Authors: Junshuang Z , Haiming L , Wanyi T , Lianguang L , Mingyang L
Published: July 2020

The DC-bias experiments were carried out on two identical single-phase autotransformers which parameters are 250MVA/500kV. The aim of the experiments was to test the ability of transformers for withstanding DC bias. The variation laws of the electrical quantity, the temperature rise, vibration with the increasing DC current under no-load are obtained. The effective value of the exciting current under DC bias is much higher than the normal no-load exciting current. The reference for the DC bias experiments of large transformers can be provided through this method.
Research on detection method for aviation bus based on electrical characteristics
Authors: Du Tingting , Jia Qingzhong , Li Yao
Published: July 2020

Based on the current situation of aviation bus detection, this paper analyzes the application limitations and shortcomings of existing detection methods. On this basis, an improved detection method in frequency-domain for two common aviation buses with different structures based on TDR technology is designed, and the detection of hard faults is used as an example to explain the detection strategy, application difficulties and solutions. Besides, the detection of soft faults for aviation bus are emphatically studied based on this method. The experimental results show that the scheme has high feasibility and good diagnostic accuracy, which provides an important reference value in engineering for reducing the difficulty and improving the efficiency of electrical fault detection for aviation bus.
Study on Utility Factor for Energy Consumption of Hybrid Electric Bus
Authors: Li Jingyuan , An Xiaopan , Liu Yu , Yu Hanzhengnan , Lv He , Hu Xi
Published: July 2020

Due to the environmental benefits of hybrid electric vehicles, the vehicle population would steadily grow in the next several decades. This paper analyses a large number of road data of buses. The Daily Vehicle Kilometers Travelled of new energy vehicles is 139km and that of internal combustion engine vehicles is 143km. With 50% coverage, both NEVs and ICEVs are 135km. With 80% coverage, both NEVs and ICEVs are 185km. Hybrid electric buses are charged at least once a day. The average charging frequency is 2 times a day in summary. Then construct the utility factor of bus for calculating the comprehensive energy consumption. To verify the validity, a group of experiments were carried out and a new calculation formula was conducted. The comprehensive results by using UF(B) can help users to understand actual energy consumption more clearly.
A Two-stage Demand Response Strategy for Datacenters in the Smart Grid Environment
Authors: Li Yuling , Wang Xiaoying , Luo Peicong , Huang Dingchang , Zhao Mengmeng
Published: July 2020

As a large load of the smart grid, datacenters usually have a huge demand for power. Datacenter participation in demand response programs of smart grids can help the grid to adjust the load while reducing its own power costs so as to save electricity costs. In this paper, we designed a two-stage demand response participation strategy to alleviate the peak load pressure of the gird and reduce the power cost of the datacenter. The first stage determines whether to participate in demand response according to the real-time electricity prices variation of the power grid and incentive information will be sent to encourage users to participate in the program to help shave the peak load. In the second stage, the datacenter interacts with its users by allowing users to submit bid information by auction. Then the datacenter selects the tasks of the winning users to postpone processing with awards, which reduces the electricity costs of the datacenter and effectively meets the demand response requirements of the smart grid. In this way, the goals of both parties could be achieved.
Real-time dispatch strategy of microgrid based on fuzzy control of energy storage
Authors: Li Nailiang , Wang Xiuli , Kuang Yi , Zhang Shujie , Zhao Hongyang
Published: July 2020

Microgrid (MG) is effective to absorb the distributed renewable energy source (RES). Considering the uncertainty of RES and load, this paper proposes a fuzzy rule of energy storage system (ESS) and gets its output by anti-fuzzification in the real-time dispatch stage after receiving the actual load and RES value. Based on the envelope principle and fuzzy control, a grid-connected MG scheduling model is established. Considering the ultra-short-term forecasted data at the beginning of an hour, a receding-horizon scheduling model which includes the constraints of ladder price, ESS, RES, etc. and aims at the lowest operating cost, is established to correct the day-ahead scheduling error as the basic value of real-time scheduling at subsequent times. Taking a MG in Shaanxi Province as an example, the proposed strategy ensures the rapid and economic operation of MG.
Application of Fractional Order PI Control in Single-phase Active Power Factor Corrector
Authors: Jianfeng Jiang , Shengze Chen , Xijun Yang , Zikun Cai
Published: July 2020

Single-phase active power factor corrector (APFC) can eliminate harmonic current pollution to the grid harmonic current. APFC uses a double closed-loop control structure with a voltage outer loop and a current inner loop. Although this control method is very simple, the dynamic response characteristics need to be improved. After analyzing the definition of fractional PID and the design process of fractional PI controller parameter, the fractional-order operators is calculated by using the Oustaloup approximation algorithm, so that a double closed-loop variable coefficient PI controller with a voltage outer loop and a current inner loop are designed in APFC to adopt fractional PI control. The pure resistive load is taken as an example for simulation analysis and compared with the three conditions of the traditional PI controller. The results demonstrate that the APFC can obtain good dynamic and static characteristics by adopting double closed-loop fractional PI control with proper order.
Transformer Fault Diagnosis Based on RapidMiner and Modified ELM Algorithm
Authors: Zhong Ji-you , Wei Jin-xiao , Wu Xiao-rong , Tang Hao
Published: July 2020

For transformer fault diagnosis, the three ratio method lacks of encoding, and artificial intelligence methods lack of anti-interference ability.Thus, a new method of transformer fault diagnosis based on RapidMiner and modified particle swarm optimization Extreme Learning Machine (RM-MPSO-ELM) is proposed. Firstly, RapidMiner picks out the most relevant input variables of the transformer fault. then, using the modified particle swarm algorithm to optimize the parameters for Extreme Learning Machine. Finally, using the ELM to identify the potential of transformer fault, the diagnostic performance of IEC three ratio method, support vector machine (SVM) method and different combinations of ELM algorithm are also compared. The results show that the proposed method achieves higher diagnosis precision.
Analysis of Electrical Model of Data Center Power System
Authors: Zhen Chai , Tiezheng Zhao , Wen Jiang
Published: July 2020

The electrical structure of the power distribution system in data center is generally a tree-like structure, with fewer branches closer to the power supply side and more branches closer to the load side. In this article, the electrical topology structure diagram is established, and the structure of power distribution network between 10kV input line and power distribution units is discussed. In the electrical structure of power system, 10kV distribution cabinets and 400V distribution cabinets are connected with electrical equipment such as electrical cable, transformer or enclosed busbar. By analysing the equivalent impedance model of equipment above, the theoretical impedance values are obtained.
MTPA Control of IPMSM Drives Assisted by Deep Neural Network
Authors: Zhang Bin , Sun Tianfu , Jia Chengli , Yang Riyang , Long Linghui , Liang Jianing
Published: July 2020

In this paper, a novel MTPA control scheme assisted by deep neural network is proposed based on a virtual signal injection concept. The deep neural network models the complex relationship between the electromagnetic torque and the d- and q-axis currents. The mathematical model in the conventional virtual signal injection MTPA control is substituted by the deep neural network. In this way, the MTPA control errors of conventional mathematical model based MTPA control schemes and conventional virtual signal injection based MTPA control schemes due to the neglect of the derivatives of machine parameters with respect to current angle or d-axis current can be avoided. The proposed control scheme was assessed by simulations under various operating conditions. Simulation results illustrate that the proposed MTPA control scheme could control the IPMSM operating on the MTPA points accurately and the errors caused by the neglect of the derivatives of machine parameters with respect to current angle or d-axis current were avoided.
Numerical simulation of convective heat transfer of microencapsulated phase change material slurrys in a circular tube
Authors: Ye H X , Zhao J D
Published: July 2020

For the Microencapsulated Phase Change Materials slurry(MPCMs)having a large latent heat during the phase change period and having a higher heat convection coefficient than the single-phase fluid, it has become a new thermal fluid of widespread investigation. In this paper, the model of equivalent specific heat is presented to numerical simulate the laminar convective heat transfer performances of MPCMs in a tube under the condition of constant heat flux. The heat transfer of MPCMs in a tube is investigated under various concentrations of MPCMs and heat flux and the correlation of the convective heat transfer with MPCMs in a tube is obtained.
Investigation of groundwater aquifer at Noborejo, Salatiga using Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES) methods
Authors: Puspita M B , Suyanto I
Published: July 2020

Local Water Supply Utility (PDAM) of Salatiga, Indonesia planned to build three new wells to meet the needs for clean water and increase the number of customers in Salatiga. The plans for the construction of the new wells are located in Randuancir, Kumpulrejo and Noborejo Sub-Districts. The groundwater aquifer layer in Noborejo Village is detected using the Electrical Resistivity Tomography (ERT) method, while the determination of the depth of aquifer layer will be controlled by the results of Vertical Electrical Sounding (VES) data processing. 4 ERT lines and 4 VES points were acquired in 2017. The processing results showed that water-containing layer tends to have a lower resistivity value. In the study area, 2 types of aquifers were found, namely unconfined aquifer (usually exploited using dug wells), and confined aquifer which are generally located on the deeper depth. Unconfined aquifers were identified with a lower resistivity value than its surroundings (20-80 Ωm) with an average depth of 25 m on all lines. Whereas confined aquifer has a higher resistivity in the range of 90 Ωm. However, confined aquifers are only found with certainty in Line 1, while in other Lines the possibility of a confined aquifers existence is smaller.
Utilization of baglog waste as bokashi fertilizer with local microorganisms (MOL) activator
Authors: Sunarya D S , Nisyawati  , Wardhana W
Published: July 2020

The purpose of the research is to producing bokashi fertilizer from baglog waste treatment with variations of effective microorganism (EM-4) activator, local microorganism (MOL) papaya, MOL banana hump, and MOL cow dung. The research was conducted in February - March 2019 in the central hydroponics greenhouse of Agro Tourism Cilangkap, East Jakarta. Baglog waste as bokashi fertilizer was made with 6 treatment combinations (P0 – P5). The measured bokashi parameters included nutrient content of Carbon (C), Nitrogen (N), Phosphorus (P) and Potassium (K). These parameters were then compared with compost quality standards according to SNI 19-7030-2004. The results showed that bokashi fertilizer was able to be made within 21 days, in which the nutrient content parameters were in accordance with SNI 19-7030-2004. Overall, the resulting bokashi fertilizer contains much higher K elements than N and P. The findings confirmed that bokashi fertilizer with MOL activator has superior quality (in C, N, P, and K content) compared to that of with EM-4 activator.
Temperature-dependent c-axis lattice-spacing reduction and novel structural recrystallization in carbon nano-onions filled with Fe3C/α-Fe nanocrystals
Authors: Boi Filippo S , Li Jiaxiang , Odunmbaku Omololu , Liu Mengjiao , Medranda Daniel , Taallah Ayoub , Lei Li , Wang Shanling
Published: July 2020

Carbon nano-onions are approximately spherical nanoscale graphitic shells. When filled with ferromagnetic Fe3C/α-Fe nanocrystals, these structures have several important applications, such as point electron-sources, magnetic data recording, energy storage, and others, that exploit the interaction of either or both the shells and the magnetic moments in the filling. Despite these applications receiving much recent attention, little is known about the structural relationship between the carbon shells and the internal nanocrystal. In this work, the graphitic c-axis lattice-spacing in Fe3C/α-Fe-filled multi-shell structures was determined by XRD in the temperature range from 130 K to 298 K. A significant reduction in the c-axis lattice-spacing was observed in the multi-shell structures. A defect-induced magnetic transition was probed and ascribed to the formation of randomly oriented ferromagnetic clusters in the recrystallized disclination-rich regions of the CNOs-shells, in agreement with the percolative theory of ferromagnetism.
Current and Historical Trends in Diversity by Race, Ethnicity, and Sex Within the US Pathology Physician Workforce
Authors: White Marissa J , Wyse Rhea J , Ware Alisha D , Deville Curtiland
Published: July 2020

Objectives

This study assessed historical and current gender, racial, and ethnic diversity trends within US pathology graduate medical education (GME) and the pathologist workforce.

Methods

Data from online, publicly available sources were assessed for significant differences in racial, ethnic, and sex distribution in pathology trainees, as well as pathologists in practice or on faculty, separately compared with the US population and then each other using binomial tests.

Results

Since 1995, female pathology resident representation has been increasing at a rate of 0.45% per year (95% confidence interval [CI], 0.29-0.61; P < .01), with pathology now having significantly more females (49.8%) compared to the total GME pool (45.4%; P < .0001). In contrast, there was no significant trend in the rate of change per year in black or American Indian, Alaskan Native, Native Hawaiian, and Pacific Islander (AI/AN/NH/PI) resident representation (P = .04 and .02). Since 1995, underrepresented minority (URM) faculty representation has increased by 0.03% per year (95% CI, 0.024-0.036; P < .01), with 7.6% URM faculty in 2018 (5.2% Hispanic, 2.2% black, 0.2% AI/AN/NH/PI).

Conclusions

This assessment of pathology trainee and physician workforce diversity highlights significant improvements in achieving trainee gender parity. However, there are persistent disparities in URM representation, with significant underrepresentation of URM pathologists compared with residents.
HIV and COVID-19: Intersecting Epidemics With Many Unknowns
Authors: Lesko Catherine R , Bengtson Angela M
Published: July 2020

As of July 2020, approximately 6 months into the pandemic of novel coronavirus disease 2019 (COVID-19), whether people living with human immunodeficiency virus (HIV; PLWH) are disproportionately affected remains an unanswered question. Thus far, risk of COVID-19 in people with and without HIV appears similar, but data are sometimes contradictory. Some uncertainty is due to the recency of the emergence of COVID-19 and sparsity of data; some is due to imprecision about what it means for HIV to be a “risk factor” for COVID-19. Forthcoming studies on the risk of COVID-19 to PLWH should differentiate between 1) the unadjusted, excess burden of disease among PLWH to inform surveillance efforts and 2) any excess risk of COVID-19 among PLWH due to biological effects of HIV, independent of comorbidities that confound rather than mediate this effect. PLWH bear a disproportionate burden of alcohol, other drug use, and mental health disorders, as well as other structural vulnerabilities, which might increase their risk of COVID-19. In addition to any direct effects of COVID-19 on the health of PLWH, we need to understand how physical distancing restrictions affect secondary health outcomes and the need for, accessibility of, and impact of alternative modalities of providing ongoing medical, mental health, and substance use treatment that comply with physical distancing restrictions (e.g., telemedicine).
Comparison of the Greek Version of the Quick Mild Cognitive Impairment Screen and Standardised Mini-Mental State Examination
Authors: Messinis Lambros , O’Donovan Mark R , Molloy D William , Mougias Antonis , Nasios Grigorios , Papathanasopoulos Panagiotis , Ntoskou Aikaterini , O'Caoimh Rónán
Published: July 2020

Introduction

Short cognitive screening instruments (CSIs) are widely used to stratify patients presenting with cognitive symptoms. The Quick Mild Cognitive Impairment (Qmci) screen is a new, brief (<5mins) CSI designed to identify mild cognitive impairment (MCI), which can be used across the spectrum of cognitive decline. Here we present the translation of the Qmci into Greek (Qmci-Gr) and its validation against the widely-used Standardised Mini-Mental State Examination (SMMSE).

Methods

Consecutive patients aged ≥55 years presenting with cognitive complaints were recruited from two outpatient clinics in Greece. All patients completed the Qmci-Gr and SMMSE and underwent an independent detailed neuropsychological assessment to determine a diagnostic classification.

Results

In total, 140 patients, median age 75 years, were included; 30 with mild dementia (median SMMSE 23/30), 76 with MCI and 34 with subjective memory complaints (SMC) but normal cognition. The Qmci-Gr had similar accuracy in differentiating SMC from cognitive impairment (MCI & mild dementia) compared with SMMSE, area under the curve (AUC) of 0.84 versus 0.79, respectively; while accuracy was higher for the Qmci-Gr, this finding was not significantly different, (p = .19). Similarly, the Qmci-Gr had similar accuracy in separating SMC from MCI, AUC of 0.79 versus 0.73 (p = .23).

Conclusions

The Qmci-Gr compared favorably with the SMMSE. Further research with larger samples and comparison with other instruments such as the Montreal Cognitive Assessment is needed to confirm these findings but given its established brevity, it may be a better choice in busy clinical practice in Greece.
The Orientation of Passerine Nocturnal Migrants Following Offshore Drift
Authors: Able Kenneth P.
Published: July 2020

Nocturnal autumn passerine migrants are frequently drifted by wind or carried by downwind flight from New England to offshore islands. Most individuals in these flights are immatures. Many recover the mainland via reoriented northward flights. During fall 1972, I made field observations and performed orientation cage tests on nocturnal migrants on Block Island, Rhode Island. Migrants reached the island during four southward movements in following winds. Migration was very light or absent on most other nights. Reoriented diurnal flights left from the island immediately after the arrival of a large nocturnal migration. Northward movements occurred on two nights following daytime reoriented flights. These nocturnal movements are tentatively interpreted as constituting reoriented flights. About 27% of the 79 individuals tested in orientation cages showed significantly directional nocturnal activity. About two-thirds of these oriented basically northwestward, corresponding to the reoriented flight of free-flying birds. These and similar reorientations of immature birds can be explained by a simple compass reorientation in response to wind drift over the ocean without invoking complicated navigation mechanisms. The remaining individuals oriented toward the southeast. Eleven birds exhibited a significant eastward orientation during the first few hours after dawn; this is interpreted as a positive phototaxis. Three of four Blackpoll Warblers oriented southward. No correlation existed between the quantity of Zugunruhe and the amount of subcutaneous fat, but fatter birds were significantly more likely to show oriented nocturnal activity.
Notes on Birds of San Salvador Island (Watlings), the Bahamas
Authors: Miller J. Robert
Published: July 2020

Resident land birds of San Salvador (Watlings) Island, The Bahamas, are briefly discussed. Breeding information is given for some resident species and note made of some new records of nonresidents. The total species known for the island is 132. The addition of three resident land birds raises the probable present total of that category to 19.
Commensalism in the Little Blue Heron
Authors: Kushlan James A.
Published: July 2020

Little Blue Herons feed in association with White Ibis by using the ibis's movements to increase foraging effectiveness. When feeding near a White Ibis, a heron increased the number of prey caught without increasing its energetic costs of foraging. The strike rate of a bird was higher when feeding commensally than when feeding alone, but its success per strike did not increase because of the commensal association. This increased energy return when feeding commensally resulted from greater opportunity for commensal herons to observe and attempt to catch prey rather than from an increased probability of their catching a prey item after it had been observed. The results of this study of a non-obvious commensal relationship suggest that many previously reported associations among water birds are also commensal. It also supports the hypothesis that multispecies aggregations of ciconiiforms may be characterized by cryptic forms of commensalism.
Notes on the Puna Avifauna of Azángaro Province, Department of Puno, Southern Peru
Authors: Roe Nicholas A. , Rees William E.
Published: July 2020

In June 1975, we made the first dry (winter) season observations of puna birds in the Province of Azángaro, Department of Puno, southern Peru, adding nine species to the avifaunal list for the area. We observed no trochilids although they are known to be numerous during the wet (summer) season. Nesting of the Golden-spotted Ground-Dove (Metriopelia aymara) is described for the first time from Peru, and we report the breeding on the puna of two puna species that have been recorded on the coast in the dry season. We discuss altitudinal migration to the Pacific coast during the dry season, and include a species list for this puna region.
Photoperiodic Control of the Molt Cycle in the Chaffinch (Fringilla coelebs)
Authors: Dolnik Victor R. , Gavrilov Valery M.
Published: July 2020

The molt cycle in Chaffinches (Fringilla coelebs) has a circannual periodicity under constant photoperiodic conditions (12:12LD, 20:4LD). The molt cycle and/or rate, however, can be modified by artificial alteration of daylength. The time of onset and completion of the post-nuptial molt in Chaffinches under natural conditions is a remote expression of vernal photostimulation. The timing of the molt is initiated at the end of the unifactorial phase of photoperiodic control. The onset of molt is induced after a latent period and its termination after another period, i.e. the molt begins and ends spontaneously. Under natural conditions, daylength immediately before and during the molt does not control either the time of onset or of termination of molt. The additional control system increases the rate of the molt in its early phase under short days, whereas under long days it decreases the rate of molt in its late phase. This system may play an adaptive role in synchronizing the end of the molt among birds that begin molt at different times.

The postjuvenal molt begins and finishes spontaneously under control of a program of the individual development of juveniles. Short days increase the rate of molt and initiate earlier onset and completion, whereas long days decrease the rate of the molt and delay the times of onset and completion. Juvenile birds from late broods molt more rapidly than those from early broods. A combination of different programs and photoperiodic control of the molt synchronizes the termination of the molt in juveniles from early and late broods under natural conditions in summer and autumn.
Reproductive Bioenergetics of Wood Ducks
Authors: Drobney Ronald D.
Published: July 2020

A model for the daily energy requirements during egg production was developed for Wood Duck (Aix sponsa) hens laying a 12-egg clutch. Reproductive requirements are high, because Wood Ducks lay large clutches of relatively large eggs that have a high energy density. Costs totaled 5,996 kJ and included 2,969 kJ for carbohydrates and lipids, 1,595 kJ for protein, and an estimated 1,432 kJ for biosynthesis. Both are the temporal distribution of costs and the use of stored fat reserves are thought to be important factors enabling hens to meet these large requirements. Costs equivalent to that of an entire egg are incurred for only 6 days during the cycle, because costs are distributed over an 18-day period rather than the 12 days of laying. The energy content of body fat expended by hens was sufficient to account for 88% of the estimated requirements for biosynthesis and the nonprotein fraction of the oviduct and clutch. Protein and minerals are primarily dietary requirements and are obtained by foraging for invertebrates during laying. Although an egg contains only about 5 g of protein, hens must consume large numbers of invertebrates to meet this requirement. The ability to meet most nonprotein requirements with stored fat may therefore be essential to ensure that hens have enough time to forage for invertebrates.
Effect of Season on the Energetics, Body Composition, and Cage Activity of the Field Sparrow
Authors: Olson John B. , Kendeigh S. Charles
Published: July 2020

A linear correlation of existence metabolism (Mkcal = kcal·bird-1·day-1) with temperature (T = °C) was obtained for winter acclimatized Field Sparrows (Spizella pusilla) on a 10-h photoperiod (males: Mkcal = 15.59-0.285T; females: Mkcal = 14.69-0.261T). A curvilinear relationship was obtained for summer acclimatized birds on a 15-h photoperiod (males: Mkcal = 16.40 + 0.0001T3 - 0.0002T2 - 0.3662T; females: Mkcal = 15.87 + 0.0036T2 - 0.3911T). Significant differences between summer- and winter-acclimatized birds occurred only at temperatures below 0°C. The lower limit of temperature tolerance was -13° to -14°C under a constant 10-h photoperiod and under fluctuating outdoor conditions and was somewhat lower under a constant 15-h photoperiod. The upper limit of temperature tolerance was about 41°C in the summer. With caged birds under fluctuating outdoor conditions, there was an increase in metabolized energy, existence metabolism, body protein, weight, and lipid content in the autumn and a decrease in the spring. During cold waves in winter, there was commonly an immediate drop in weight before increased metabolized energy brought recovery. In half of the birds, recovery was incomplete and mortality resulted. Coefficients of food utilization varied from 0.71 under a 10-h photoperiod to 0.79 under a 15-h photoperiod and from 0.72 to 0.86 under outdoor conditions. With death from cold or heat stress there was a loss of water, lipids, and proteins. The loss of water was greater under heat stress. Nocturnal activity (Zugunruhe) developed in a different pattern in spring than in autumn and was not accompanied by premigratory fattening in the spring. In several respects, the metabolic and behavioral responses of the Field Sparrow are intermediate between those of long distance migrants and permanent residents, indicating that they may be evolving from a migratory to a nonmigratory status.
Estimation of Distance of Singing Conspecifics by the Carolina Wren
Authors: Richards Douglas G.
Published: July 2020

Measurements of the propagation of sound in a forest have shown that signal degradation is unavoidable but to some degree predictable. Carolina Wrens (Thryothorus ludovicianus) have a song structure suited for the estimation of distance by a comparison of the relative degradation of the components of the signal. Playback experiments using song recorded at two distances from a singing wren demonstrated that wrens can use cues other than the absolute attentuation of the sound for the estimation of the distance of the singer. The wrens responded to the near-sounding song by attack and to the far-sounding song by countersinging. The ability of the wrens to use the distance information in the song serves the same purpose as the recognition of familiar neighbors: conservation of time and energy used in territorial defense.
Song Variation within a Population of White-Eyed Vireos (Vireo griseus)
Authors: Bradley Richard A.
Published: July 2020

Intrapopulational variation in the songs of territorial male White-eyed Vireos (Vireo griseus griseus) was studied at Gainesville, Florida during 1977 and 1978. The motifs in the song repertoires of 40 color-banded males were analyzed in detail. Individual male White-eyed Vireos used 1-14 different motifs. A quantitative sequence-comparison measure of song dissimilarity was used to compare song repertoires. No relationship was found between the dissimilarity of individuals' song repertoires and the map distances between their territories. Unexpectedly, pairs of neighboring males had more dissimilar song repertoires than non-neighboring pairs of vireos.
AciDB 1.0: a database of acidophilic organisms, their genomic information and associated metadata
Authors: Neira Gonzalo , Cortez Diego , Jil Joaquin , Holmes David S
Published: July 2020

Motivation

There are about 600 available genome sequences of acidophilic organisms (grow at a pH < 5) from the three domains of the Tree of Life. Information about acidophiles is scattered over many heterogeneous sites making it extraordinarily difficult to link physiological traits with genomic data. We were motivated to generate a curated, searchable database to address this problem.

Results

AciDB 1.0 is a curated database of sequenced acidophiles that enables researchers to execute complex queries linking genomic features to growth data, environmental descriptions and taxonomic information.

Availability and implementation

AciDB 1.0 is freely available online at: http://AciDB.cl. The source code is released under an MIT license at: https://gitlab.com/Hawkline451/acidb/.
Antibiotic Multidrug Resistance of Escherichia coli Causing Device- and Procedure-related Infections in the United States Reported to the National Healthcare Safety Network, 2013–2017
Authors: Kourtis Athena P , Sheriff Edward A , Weiner-Lastinger Lindsey M , Elmore Kim , Preston Leigh Ellyn , Dudeck Margaret , McDonald L Clifford
Published: July 2020

Background

Escherichia coli is one of the most common causes of healthcare-associated infections (HAIs); multidrug resistance reduces available options for antibiotic treatment. We examined factors associated with the spread of multidrug-resistant E. coli phenotypes responsible for device- and procedure-related HAIs from acute care hospitals, long-term acute care hospitals, and inpatient rehabilitation facilities, using isolate and antimicrobial susceptibility data reported to the National Healthcare Safety Network during 2013–2017.

Methods

We used multivariable logistic regression to examine associations between co-resistant phenotypes, patient and healthcare facility characteristics, and time. We also examined the geographic distribution of co-resistant phenotypes each year by state and by hospital referral region to identify hot spots.

Results

A total of 96 672 E. coli isolates were included. Patient median age was 62 years, and 60% were female; more than half (54%) were reported from catheter-associated urinary tract infections. From 2013 to 2017, 35% of the isolates were nonsusceptible to fluoroquinolones (FQs), 17% to extended-spectrum cephalosporins (ESCs), and 13% to both ESCs and FQs. The proportion of isolates co-resistant to ESCs and FQs was higher in 2017 (14%) than in 2013 (11%) (P < .0001); overall prevalence and increases were heterogeneously distributed across healthcare referral regions. Co-resistance to FQs and ESCs was independently associated with male sex, central line–associated bloodstream infections, long-term acute care hospitals, and the 2016–2017 (vs 2013–2014) reporting period.

Conclusions

Multidrug resistance among E. coli causing device- and procedure-related HAIs has increased in the United States. FQ and ESC co-resistant strains appear to be spreading heterogeneously across hospital referral regions.
Effective GC-MS procedure for detecting iso-LSD in urine after base-catalyzed conversion to LSD
Authors: Clarkson Edward D , Lesser David , Paul Buddha D
Published: July 2020

A sensitive method is described to detect isolysergic acid diethylamide (iso-LSD) in urine. The compound was extracted from urine and converted to a C-8 carbanion by sodium ethoxide in ethanol. Protonation of the carbanion by water selectively produced LSD. The conversion of iso-LSD to LSD was almost quantitative (98%). The product was purified by solid-phase fractionation and acid–base separation techniques. The trimethylsilyl derivative of LSD was detected by a gas chro-matography–mass spectrometry method. The overall recovery of the procedure was approximately 69%. Quantification of iso-LSD was linear over the concentration range 50–2000 ng/L. In specimen analysis, iso-LSD was detected when the LSD concentration was below the limit of the detection (50 ng/L) of the procedure. Because iso-LSD is a byproduct of illicit preparation of LSD, presence of iso-LSD in urine is an indication of LSD use.
Commutability of control materials in glycohemoglobin determinations
Authors: Mosca Andrea , Paleari Renata , Madè Alessandro , Ferrero Carlo , Locatelli Massimo , Ceriotti Ferruccio
Published: July 2020

The intermethod variabilities of control materials and patient blood samples for the measurement of glycohemoglobin were compared. Sets of 50 blood samples and 15 control materials were analyzed by HPLC and affinity and immunochemical methods. For each pair of methods, the distances of the materials from the regression line of patient blood results (expressed as normalized residuals) were calculated. Only two of 15 controls had normalized residuals exceeding 3 standard deviations from the regression line. Total hemoglobin (Hb) content, Hb derivatives, and cellulose acetate electrophoresis demonstrated that only a minority of controls could be considered similar to patients’ blood samples. We selected Menarini’s and our home-prepared controls to simulate calibration of the different techniques by these materials. Intermethod calibration succeeded mostly in harmonizing results obtained by HPLC methods. On the contrary, calibration of the immunochemical techniques (Boehringer and Roche) did not improve intermethod agreement to a clinically useful level.
Evaluation of growth hormone assays using ratio plots
Authors: Andersen Marianne , Petersen Per Hyltoft , Blaabjerg Ole , Hangaard Jørgen , Hagen Claus
Published: July 2020

To permit comparison between growth hormone (GH) results obtained using the Pharmacia polyclonal assay and the Delfia monoclonal assay, we used both methods to measure GH concentrations in peak GH responses to the pyridostigmine-growth-hormone-releasing-hormone (PD-GHRH) test and in unstimulated samples from 40 healthy adults and 31 patients with suspected GH deficiency. Ratio plots were used for the comparison, and acceptability criteria were based on inherent analytical imprecision and on analytical quality specifications. The mean ratio (r; Pharmacia/Delfia) for the peak GH responses in 40 healthy adults was calculated to be 1.59, and the 95% prediction interval for ratios fulfilling the imprecision criterion was applied. For GH values >1 mIU/L, the peak and unstimulated GH ratios in healthy adults and patients were within the 95% prediction interval, and fulfilled the biological criterion as well. Therefore, the conversion factor of 1.59 is applicable for the evaluation of GH-stimulation tests.
Changes in Plasma Cystatin C after Renal Transplantation and Acute Rejection in Adults
Authors: Le Bricon Thierry , Thervet Eric , Benlakehal Mourad , Bousquet Bernard , Legendre Christophe , Erlich Daniele
Published: July 2020

Background: Cystatin C has recently been proposed as an alternative marker of glomerular filtration rate. The diagnostic value of plasma cystatin C for the longitudinal assessment of kidney function after renal transplantation, however, has not been addressed.

Methods: Renal function was evaluated in 30 adults receiving renal transplants (46 ± 9 years, mean ± SD) and in 56 healthy controls (38 ± 10 years) using cystatin C. Plasma cystatin C was determined daily starting the day of surgery and for 3 weeks after surgery by an immunonephelometric assay.

Results: Plasma concentration significantly decreased during the first week (−44% vs −29% for creatinine). Plasma cystatin C correlated with plasma creatinine (r = 0.741; P <0.0001) and the reciprocal of the creatinine clearance estimated by the Cockcroft-Gault formula (r = 0.882; P <0.001). In all three cases of acute renal impairment, the increase in plasma cystatin C values was more prominent than that of creatinine.

Conclusions: Plasma cystatin C is an alternative and accurate marker of allograft function in adult transplant patients. Increased sensitivity compared with creatinine for the detection of acute reduction in glomerular filtration rate allows in some cases a more rapid diagnosis of acute rejection or treatment nephrotoxicity.
Evaluation of a Capillary Electrophoresis Method for Routine Determination of Hemoglobins A2 and F
Authors: Cotton Frédéric , Lin Changying , Fontaine Bernard , Gulbis Béatrice , Janssens Jacques , Vertongen Françoise
Published: July 2020

Hemoglobin A2 (Hb A2) and hemoglobin F (Hb F) are important analytes in the diagnosis and follow up of Hb diseases. We evaluated a new capillary zone electrophoresis (CZE) kit for Hb A2 and Hb F measurements. The imprecision ranged from 3% to 6% for Hb A2 and Hb F at physiological and pathological concentrations. The method compared well with cation-exchange HPLC for Hb A2 and Hb F and with anion-exchange chromatography in microcolumns (MAEC), for Hb A2. Nevertheless, higher results were obtained [Hb A2 CZE (%) = 1.233 Hb A2 HPLC − 0.2; Hb A2 CZE (%) = 1.190 Hb A2 MAEC + 0.1; Hb FCZE (%) = 1.118 Hb FHPLC + 0.4], and new reference values had to be determined (Hb A2 2.7–3.8%; Hb F <1.2%). Quantification of Hb A2 was not influenced by Hb S. Measurement of Hb F was accurate and precise except at low concentrations in Hb AS patients. This new CZE kit is rapid, precise, and reliable, and seems appropriate for use in clinical laboratories.
Terbium and Rhodamine as Labels in a Homogeneous Time-resolved Fluorometric Energy Transfer Assay of the β Subunit of Human Chorionic Gonadotropin in Serum
Authors: Blomberg Kaj , Hurskainen Pertti , Hemmilä Ilkka
Published: July 2020

Background: Fluorescence resonance energy transfer (FRET) is a powerful tool in analytical chemistry. The aim of the present work was to use FRET to design a homogeneous immunoassay.

Methods: We used a highly fluorescent terbium (Tb3+) chelate (donor) and the organic fluorochrome rhodamine (acceptor) combined with time-resolved detection of the acceptor emission in homogeneous assay format for the measurement of the β subunit of human chorionic gonadotropin (βhCG) in serum. We used two antibodies labeled with Tb3+ and rhodamine, respectively, recognizing different epitopes on βhCG. The close proximity between the labels in the immunocomplex permitted energy transfer between the pulse-excited Tb3+ donor (decay time >1 ms) and the acceptor rhodamine (decay time of 3.0 ns). The prolonged emission of donor-excited acceptor (energy transfer) was measured after the short-lived background and acceptor emissions had decayed. The emission of donor-excited rhodamine was measured at a wavelength of where the emission of unbound donor is minimal.

Results: The energy transfer signal was directly proportional to the βhCG concentration in the sample. The limit of detection was 0.43 μg/L, and the assay was linear up to 200 μg/L. Total assay imprecision in the range 10–185 μg/L was between 7.5% and 2.8%.

Conclusions: Although less sensitive than heterogeneous, dissociation-enhanced europium-based separation assays, the presented assay format has advantages such as speed and simplicity, which make the assay format ideal for assays requiring a high throughput.
Human Anti-Animal Antibody Interferences in Immunological Assays
Authors: Kricka Larry J
Published: July 2020

Purpose: The scope and significance of human anti-animal antibody interference in immunological assays is reviewed with an emphasis on human anti-animal immunoglobulins, particularly human anti-mouse antibodies (HAMAs).

Issues: Anti-animal antibodies (IgG, IgA, IgM, IgE class, anti-isotype, and anti-idiotype specificity) arise as a result of iatrogenic and noniatrogenic causes and include human anti-mouse, -rabbit, -goat, -sheep, -cow, -pig, -rat, and -horse antibodies and antibodies with mixed specificity. Circulating antibodies can reach gram per liter concentrations and may persist for years. Prevalence estimates for anti-animal antibodies in the general population vary widely and range from <1% to 80%. Human anti-animal antibodies cause interferences in immunological assays. The most common human anti-animal antibody interferent is HAMA, which causes both positive and negative interferences in two-site mouse monoclonal antibody-based assays. Strategies to prevent the development of human anti-animal antibody responses include immunosuppressant therapy and the use of humanized, polyethylene glycolylated, or Fab fragments of antibody agents. Sample pretreatment or assay redesign can eliminate immunoassay interferences caused by anti-animal antibodies. Enzyme immunoassays, immunoradiometric assays, immunofluorescence, and HPLC assays have been designed to detect HAMA and other anti-animal antibodies, but intermethod comparability is complicated by differences in assay specificity and lack of standardization.

Conclusions: Human anti-animal antibodies often go unnoticed, to the detriment of patient care. A heightened awareness on the part of laboratory staff and clinicians of the problems caused by this type of interference in routine immunoassay tests is desirable. Efforts should be directed at improving methods for identifying and eliminating this type of analytical interference.
In Vitro Diagnostics in Diabetes: Meeting the Challenge
Authors: Turner Anthony PF , Chen Beining , Piletsky Sergey A
Published: July 2020

Diabetes is one of the leading causes of death and disability in the world. There is a large population in the world suffering from this disease, and the healthcare costs increase every year. It is a chronic disorder resulting from insulin deficiency and hyperglycemia and has a high risk of development of complications for the eyes, kidneys, peripheral nerves, heart, and blood vessels. Quick diagnosis and early prevention are critical for the control of the disease status. Traditional biosensors such as glucose meters and glycohemoglobin test kits are widely used in vitro for this purpose because they are the two major indicators directly involved in diabetes diagnosis and long-term management. The market size and huge demand for these tests make it a model disease to develop new approaches to biosensors. In this review, we briefly summarize the principles of biosensors, the current commercial devices available for glucose and glycohemoglobin measurements, and the recent work in the area of artificial receptors and the potential for the development of new devices for diabetes specifically connected with in vitro monitoring of glucose and glycohemoglobin HbA1c.
Ultrarapid, Ultrasensitive One-Step Kinetic Immunoassay for C-Reactive Protein (CRP) in Whole Blood Samples: Measurement of the Entire CRP Concentration Range with a Single Sample Dilution
Authors: Tarkkinen Piia , Palenius Tom , Lövgren Timo
Published: July 2020

Background: Recently, measurement of very low concentrations of C-reactive protein (CRP) has gained popularity as a potential new means for predicting the risk of future cardiac complications. In this study, we demonstrate the feasibility of a kinetic, one-step microparticle assay for quantitative determination of extremely low and high CRP concentrations in the limited timeframe typical for point-of-care testing.

Methods: A noncompetitive, kinetic CRP immunoassay was developed that uses individual, porous microparticles as the solid phase. The microparticles were covalently coated with a monoclonal capture antibody, and the monoclonal detection antibody was labeled with europium. The one-step binding reaction was stopped by washing after 2 min of incubation, and the fluorescence signal of individual particles was measured.

Results: The analytical detection limit (mean of zero calibrator + 3 SD) was 0.00016 mg/L CRP. Clinical samples were diluted 400-fold before assay to cover the CRP concentration range of 0.064–1200 mg/L. The assay correlated well with the Dade Behring N High Sensitivity CRP assay (for 0–10 mg/L, r = 0.969, Sy|x = 0.68, n = 54; for 0–350 mg/L, r = 0.969, Sy|x = 11.7, n = 100). The within- and between-run CVs based on calculated concentrations were, respectively, 9–16% and 14% at 0.11 mg/L, 4.5–12% and 8.2% at 4.2 mg/L, and 3.5–6.3% and 4.4% at 105 mg/L, with a CV <15% at 0.2 mg/L and above.

Conclusions: Use of the kinetic microparticle approach combined with time-resolved fluorometry allows ultrasensitive quantification of CRP in whole blood in 2 min with a linear assay range spanning more than four orders of magnitude.