bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistivity and Formation of Intermetallic Layer in Aluminum-Steel Clad Strip
Authors: Křivská B , Šlapáková M , Králík R , Bajtošová L , Cieslar M , Grydin O , Stolbchenko M , Schaper M
Published: September 2021

Cladding of two dissimilar materials such as aluminum and austenitic steel can bring outstanding material characteristics beyond the ones of each conventional monomaterials. The study focused on development of an Al-Fe-rich intermetallic phase formed on the aluminum/steel interface during heat treatment. Electrical resistivity measurements were performed to monitor diffusion processes and phase transformations during isochronal and isothermal annealing. Resistivity measurement results were supplemented by microscopic methods revealing the interfacial microstructure.
Study of the deformation process in an equal-channel step matrix of a new design based on computer simulation
Authors: Naizabekov A , Panin E , Lezhnev S , Volokitina I
Published: September 2021

The paper presents the results of computer simulation of the deformation process in equal-channel step matrix, the distinctive feature of which is the location of intermediate channel at two angles to the input and output channels. Models with values of the inclination angle in the longitudinal direction (angle α) of 135 degrees and inclination angles in the transverse direction (angle β) of 15, 25 and 35 degrees are considered. To study the stress-strain state, the following parameters were considered: equivalent strain (total strain intensity); equivalent stress (stress intensity), and the resulting deformation force. It was found that with an increase in the value of the angle β, all the characteristics of the stress-strain state increase in their absolute value. When the angle β increases from 0 to 35 degrees, the equivalent strain increases by an average of 22÷25%. The analysis of the forces showed that when the value of the angle β increases, the deformation force increases at both stages, the nature of the increase is non-monotonic. The increase in force occurs sequentially by 10, 12 and 23 kN, which indicates the exponential nature of increase in force depending on the value of the angle β. The maximum force value of 257 kN that occurs when using a matrix with angle of β=35° exceeds the standard value for β=0° by only 22%. Therefore, the best option for performing equal-channel step pressing with the flow of metal in 3 planes can be considered a matrix with angle α=135° and angle β=35°.
Tensile properties evaluation of additively manufactured AISI 316L thin wall and bulk material using various miniaturized specimen geometries
Authors: Rzepa S , Melzer D , Koukolíková M , Konopík P , Brázda M , Vavřík J
Published: September 2021

Additive Manufacturing is an innovative technology, which allows creating structures of complex and unique geometries layer by layer. The mechanical properties of deposited objects can vary depending on their length, thickness and deposition orientation due to different cooling rates and various thermal conductivity. Austenitic steel AISI 316L, deposited using direct energy deposition technology, was an experimental material. The technology employs a high-power laser beam as an energy source for the powder melting. During the process, a powder is blown through the nozzle by protective gas into the processing area and subsequently molten. The aim of the study was to compare basic mechanical properties of the specimens extracted from a thin wall and a bulk material. The specimens were tested in horizontal and vertical orientations in relation to the build orientation in machined and as-deposited states. The tensile characteristics of proportional and non-proportional specimens were investigated within the study. The miniaturized tensile test specimens were employed in order to examine the strength and elongation of the experimental material. The mechanical testing results were complemented by microstructural analysis using a light microscopy (LM). Based on the obtained results, it can be concluded that the specimen proportionality affects not only the specimen elongation, but also the strength values of investigated material.
Comparison of the optical and electrical energy band gap of a thin layer of polyelectrolyte based on MEH-PPV and KI
Authors: Szindler M M , Szindler M
Published: September 2021

A thin layer of polyelectrolyte based on Poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) and potassium iodide (KI) was prepared using the sol-gel method. Comprehensive studies of the optical and electrical energy gap of the produced material were carried out. Using the Thermo Scientific Evolution 220 spectrophotometer equipped with a xenon lamp in the wavelength range from 190 to 1110nm, the absorbance A was measured. The optical energy gap (Egopt) was calculated. With the change in the concentration of potassium iodide, the change in the energy band gap of polyelectrolyte thin film was registered. In this paper, the cyclic voltammetry (CV) for testing electrochemical properties was used. The location of energy levels HOMO, LUMO and the value of the energy band gap were calculated, which is very important for polymeric materials that conduct electricity and the possibility of their use in solar cells.
Bi-Directional System Coupling for Conjugate Heat Transfer and Variable Leakage Gap CFD Analysis of Twin-Screw Compressors
Authors: Rane S , Kovačević A , Stošić N , Smith I K
Published: September 2021

Oil-free twin-screw compressors are essential in various industrial applications where clean compressed gas is required. Due to the absence of the cooling oil in these machines, thermal deformations are large. Hence, design clearances are generally set at a relatively large value of more than 150 μm. Leakage through these clearances are the primary source of flow loss. It is essential to predict the change of the gap size in operation accurately so that the design clearances can be minimised, allowing reliable operation and maximising compressor efficiency. To achieve this, CFD and Structural solvers were combined. The CFD model uses a single domain deforming grid of the twin-screw rotors generated in SCORG grid generator, together with ANSYS CFX flow solver. The thermal model of the rotors and housing uses ANSYS Structural solver. Two modelling systems were coupled bi-directionally to obtain variation in the radial leakage gap size for calculation of performance in the CFD model. The predicted compressor performance thus obtained was compared with measurements of flow, internal pressure-rise, power, specific power, volumetric and adiabatic efficiency. For the test case, three variations of radial gap size were evaluated, two of them with the uniform gap size of 10 μm and 160 μm and the third one with a variable gap size as predicted by the bi-directionally coupled model. The coupled model predicted this gap size to vary from 24 to 117 μm, thus predicting an improved flow and volumetric efficiency by 8.2%, lower indicated power by 2.5% and a higher adiabatic efficiency by 5.5%, in comparison to the design gap size of 160 μm. These predicted gap sizes could be used to improve the design clearances of the compressor by reducing them from 160 to 120 μm which would result in a better performance during operation.
Implementing the principles of operating processes schematization and of performance loss distribution when designing long-stroke reciprocating compressor stages
Authors: Yusha Vladimir L. , Busarov Sergey S. , Filkin Nikolay Yu. , Fedorova Maria A. , Denisenko Vladimir V. , Goncharenko Alexander A. , Shipov Vyacheslav B. , Bessonov Oleg G.
Published: September 2021

To compress gases up to 10.0 MPa and higher, diaphragm and multistage reciprocating compressor units are used. They are heavy, massive and complicated. The results of analyzing laboratory examples of slow-speed long-stroke stages of reciprocating compressors while gas pressurizing up to such pressure have shown the possibility of solving the problems mentioned. Such stages differ from others, that is why we cannot use common design methods in this case. The performance design method for slow-speed long-stroke compressor stages with a discharge pressure of up to 10.0 MPa is based on the well-known principles of schematization of operating processes and distribution of performance losses. With regard to the experimental studies results (indicator and temperature diagrams, integral characteristics) we have found: the volumetric efficiency, which characterizes the ratio between real and theoretical compressor performance, its main components: the volume coefficient, the pressure coefficient, the temperature coefficient, and the leakage coefficient. Dependences are obtained for calculating these coefficients, which differ significantly from the known dependences for calculating high-speed compressor stages. The analysis of the influence of various factors on the performance losses of low-capacity long-stroke compressor stages of medium and high pressure revealed that the gaps in the working chamber have the maximum impact on the performance losses, the leakage coefficient significantly depending on the discharge pressure change. The volume coefficient has much less impact due to the increased stroke-to-diameter ratio of the piston, which provides a small amount of relative dead volume. The developed method can be used for preliminary calculation of compressor stages of the considered type.
Numerical simulation and optimization of centrifugal compressor return channels: methods and results
Authors: Galerkin Y.B. , Marenina L.N. , Drozdov A.A. , Solovyeva O.A. , Soldatova K.V.
Published: September 2021

The authors actively use their engineering Universal Modelling Method for gas-dynamic design of centrifugal compressors for industrial partners. Currently, there are two approaches to improving the Method: improving the preliminary design and increasing the accuracy of gas-dynamic characteristics calculation. Computational Fluid Dynamics (CFD) methods give good results for the flow path stator part. Recently, massive CFD calculations of the vaneless diffusers (VLD) characteristics were generalized by a system of algebraic equations, which replaced the previous more complex mathematical model in the Method. Then, based on CFD optimization of a large series of return channels (RCh), corrections were made to the preliminary design of this element of the flow path.

This paper presents the results of the joint CFD optimization of a vaneless diffuser and a return channel. Stator elements have many geometric parameters. For a stage with the flow rate coefficient of 0.0597 and the loading factor of 0.60, only the VLD relative radial length D
4/D
2, the number and the inlet angle of the return channel vanes were optimized. Engineering calculations and design experience predicted an optimal value of D
4/D2 within the interval 1.9 - 2.0. CFD optimization demonstrated almost linear reduction of the total head loss towards the end of the investigated range D
4/D2 = 2.3. After careful optimization of the U-bend, the optimization of D
4/D2 was repeated. The influence of on the loss coefficient has decreased, but the value of D
4/D
2 = 2.3 is still far from optimum. It significantly exceeds technically acceptable radial size. The result obtained influenced the design plan of future calculation experiments with a large series of stator elements of the stages in a practically significant range of design parameters.
Optimal Designed Experiments for Reliable Model Calibration of a fixed-speed Scroll Compressor with R410A and R32
Authors: Vering Christian , Stopp Daniel , Klebig Tim , Venzik Valerius , Müller Dirk
Published: September 2021

Mainly to provide heat, the building sector accounts for about 18 % of overall global CO2 emissions. By exchanging conventional technologies in the near future, heat pumps are a key technology to systematically decarbonise the heat supply chain. The efficiency of a heat pump strongly depends on its compressor’s efficiency. Thus, the compressor is the subject of current research. The compressor performance depends on the fluid with its inlet and outlet conditions, an appropriate oil, and the mechanic compression principle. Based on that, the performance is expressed by the isentropic and volumetric efficiency. To describe a compressor in detail and fluid independent is challenging. Therefore, many theoretical studies have been conducted, while in comparison experimental studies are rare. To overcome this imbalance, this study focuses a detailed experimental investigation of a 4 kW Copeland scroll compressor with R410A and R32 on a fully automated compressor test stand. Within this paper, we present a method for in-depth uncertainty analysis, which ensures the usability and comparability of our experimental results to other experiments. We store our results in optimal calibrated simulation models based on optimal experimental design. This allows us to reduce experimental effort up to 70 % compared to full factorial experimental designs. To prove the method in a compressor and two fluids, we apply it to a fixed-speed scroll compressor with R410A and R32. The test stand is able to conduct all experiments automatically and part load behaviour of both refrigerants can be summarized in a model according to recent Literature with an overall uncertainty below 8 % for R410A. For R32, the method fails. Utilizing this method, we aim at open-source experiments in order to accelerate the solution of complex research questions.
Research on fault diagnosis and early warning of reciprocating compressor based on stacked convolutional autoencoder optimized by gradient differential evolution
Authors: Li H , Liu XM , Mao ZW , Zhang JJ
Published: September 2021

The reciprocating compressor is one of the key equipment in the process industrial field. Due to its complex structure and motion state, the bearing bush of the connecting rod is prone to wear failure. In the early stage of wear failure, the monitoring signal signs are very weak. As a result, it has produced bad results that identify the fault signs by using traditional data processing and spectrums analytical methods. Aiming at the early fault identification of the bearing bush, unsupervised feature mining based on auto-encoder principle and super-parameter optimization based on Gradient-Differential-Evolution are utilized, and an early-warning-model based on Gradient-Differential-Evolution and Stacked-Convolutional-Autoencoder is proposed. In order to study the sensitivity of the vibration signal and piston rod settlement signal to the early stage of wear failure, the two signals are input into the early warning model for comparison. In addition, they are fused to verify the improvement ability of multi-source signal on early warning. Moreover, to verify the early fault recognition performance of the proposed methods, the proposed method is compared with the other two early-warning-models based on Stacked-Autoencoder and Convolutional-Neural-Networks. The actual fault case analysis results show that based on the Gradient-Differential-Evolution optimization model, the difficulty of parameter setting can be effectively reduced and the proposed method has significant advantages to detect the early warning timely and effectively.
A numerical CFD simulation method using static grid based on momentum compensation for screw pumps
Authors: Yan Di , Tang Qian
Published: September 2021

Three-dimensional CFD numerical simulation is the most powerful tool for performance analysis of screw machines. This paper compares and analyzes two CFD numerical calculation methods based on moving and static grid, and proposes a static grid calculation method based on momentum compensation, which takes into account the wall velocity and fluid momentum on the rotor surface when the screw rotor rotates. That is, while the static grid is used, the rotation characteristics of the fluid domain between the rotors are considered. Compared with the commonly used static grid method, this method greatly improves the accuracy of the calculation, the calculation error of mass flow rate is reduced from 2.32% to 1.14%. At the same time, it is simple and easy to implement. It is also suitable for modelling screw machines with special-shaped rotors, which are still challenge for moving grids. The accuracy and reliability of the method are verified by comparison with the calculation results of the moving grid and the experiments.
Development of a Reconfigurable Prototype Peristaltic Compressor
Authors: Islam M , Tubbs C , Bengs C , Bradshaw C R
Published: September 2021

Traditional positive displacement compressors require valves, internal volume ratios or both to operate. These two features generate the majority of the losses in compressors. The peristaltic compressor is a novel compressor architecture that feature valve-less compression with variable volume ratios, which provides the potential for highly efficient compression. This paper will present a design of a reconfigurable prototype peristaltic compressor and illustrate how the structure of the compression chamber and actuation pattern affect the compressor efficiency. The prototype utilizes a flexible diaphragm constrained and sealed against a female die to make a compression chamber. Linear actuators with male dies press the diaphragm sequentially against the female die to move and compress the fluid. Preliminary experiments were performed using air as the working fluid for volume ratios ranging from 1.143 to 8 and operational frequencies ranging from 1.28 to 2.31 Hz. These results suggest that the actuation pattern has an impact on the major parameters such as mass flow, displacement volume, and pressure ratio which influence the overall efficiency of the compressor.
Simulation and optimisation of opened sewage concentration air cycle combined with the heat pump under actual weather conditions
Authors: Zhang Y , Guo T S , Wu W F , Li C Y , Wang X L
Published: September 2021

Opened air cycle is a promising sewage concentration technology using heated air as the medium to absorb water from the sewage. Unlike closed cycles, the air flow is directly ejected out of the system after humidification in opened cycles. Operating conditions and the circle’s efficiency are highly affected by the weather, such as the time-varying ambient temperature and relative humidity. Since the evaporating temperature relies on the ambient temperature, to restrain its dependence, the evaporator was proposed combined with the ejected air flow in this paper. Such a design could improve the efficiency of the heat pump by increasing its evaporating temperature. Simulation of the newly proposed open sewage concentration cycle was performed to investigate its thermal process and economic efficiency under actual weather conditions. Thermodynamic models of the compressor, heat exchangers and the sewage concentration chamber were established. Climatic conditions at Xi’an, China were referenced as actual weather conditions. Optimisation of the working parameters was performed to achieve higher economic index. The results demonstrated that the average monthly power consumption of the optimized cycle was 0.3508 kWh/kg. Compared with the published data of the closed cycle, the total cost of new opened cycle was nearly one-third lower.
CFD analysis on the effect of discharge port geometry of the hook and claw vacuum pumps
Authors: Theofanidis K , Lu Y , Kovacevic A
Published: September 2021

Due to the sharp discontinuities in the profile of hook and claw pumps which make it difficult to produce a good quality body fitted mesh, their CFD simulations are challenging. However, the cut-cell Cartesian meshing method is capable to handle the very complex moving geometries and is easy to setup. However it may lead to conservativeness issues. The aim of this paper is to investigate the influence of discharge port geometry of the hook and claw pump on its performance by using commercial software ANSYS Forte, which utilizes automatic mesh generation using the cut-cell Cartesian method. Firstly, five discharge ports with different geometries were designed. Secondly, the pumps with these different port configurations were set up and ran in the ANSYS Forte. Finally, the power and volume flow rate were compared. It was noticed that the geometry with the extended discharge port tip and the preliminary discharge port opening result in performance and reliability improvements. The simulation results can be used to further optimize the discharge port during the design of these machines.
Application of DLVO Modeling to Study the Effect of Silica Nanofluid to Reduce Critical Salt Concentration in Sandstones
Authors: Muneer Rizwan , Hashmet Muhammad Rehan , Pourafshary Peyman
Published: September 2021

Critical salt concentration (CSC) is the minimum salt concentration of injected water used for different oil recovery operations, below which fines migration initiates within sandstone reservoirs having clay contents and could be one of the potential causes of formation damage. This paper estimated CSC for Berea sandstone-NaCl brine system experimentally and by using DLVO modeling based on Van der Waals and electric double layer (EDL) surface forces. Furthermore, the effectiveness of silica nanofluid to reduce CSC and control fines migration was investigated. At different salinities of the injected fluid, the experimental CSC was determined by performing corefloods and analyzing effluent turbidity and absorbance. Attractive (van der Waals) and repulsive (EDL) forces were estimated by DLVO theory to predict the value of CSC. The experimental data were used to validate the model. The application of silica nanoparticles (NPs) was studied by injecting 0.1 wt% silica nanofluid and the resultant reduction in CSC was observed. During the injection of brines at different salinities ranging from 0.2 M to 0.05 M into the sandstone porous media, fines production was detected in the effluent after the injection of 0.1M NaCl solution, indicating that the CSC was 0.1M for this sand-fine-brine (SFB) system. The zeta potentials for SFB systems of different salinities were measured by zeta-sizer and were in the range of -32 mV to -24 mV. DLVO model based on attractive and repulsive forces was then used to predict the CSC, at which the total DLVO energy shifts from negative to positive and was around 0.1M for NaCl solution. The model prediction was in close agreement with the experimental results. Both the experiment and DLVO model showed the efficiency of silica nanofluid to mitigate fines migration as no fines production was observed for 0.1M NaCl case after the treatment with nanofluid. The estimation of CSC is critical to avoid formation damage during many oil recovery processes, included but not limited to low salinity waterflooding and alkaline flooding. The utilization of nanofluid provided promising results in controlling fines migration and reducing CSC. The proposed model based on DLVO theory can work as a useful tool to predict CSC without the need for extensive experimental work.
Assessment of the corrosion susceptibility of 434 ferritic stainless steel in chloride-sulphate solution
Authors: Loto Roland T.
Published: September 2021

The corrosion polarization behaviour of 434 ferritic stainless (434ST) was studied in 1 M H2SO4 at 0.25% to 2% NaCl concentration through potentiodynamic polarization techniques and open circuit potential analysis. Results showed corrosion rate of 434ST at in 1 M H2SO4 solution at 0% NaCl concentration is 5.51 mm/y. However, at 0.25% NaCl concentration corrosion output decreased to 1.31 mm/y due to competitive adsorption mechanism with dissolved O2 atoms. Increment in NaCl concentration causes increase in corrosion rate till 1% NaCl concentration at 5.97 mm/y. After 1% NaCl concentration, the corrosion of 434ST attained threshold deterioration mechanism with values varying between 6.20 mm/y and 6.56 mm/y. Shift in corrosion potential plot with respect to 434ST at 0% NaCl concentration indicates anodic corrosion and passivation mechanism on the steel surface which was also proven from the anodic Tafel slope values. Open circuit potential plots showed plots at 2% NaCl concentration showed the least thermodynamic tendency to corrode with the strongest shift to electropositive potentials which culminated at -0.439 V at 5400 s of observation. The plot at 0% NaCl solution exhibited the most electronegative plot configuration by reason of the deteriorating reaction of SO4
2- on the steel.
Further Evidence of Psychometric Performance of the Self-care of Diabetes Inventory in Adults With Type 1 and Type 2 Diabetes
Authors: De Maria Maddalena , Fabrizi Diletta , Luciani Michela , Caruso Rosario , Di Mauro Stefania , Riegel Barbara , Barbaranelli Claudio , Ausili Davide
Published: September 2021

Background

The Self-care of Diabetes Inventory (SCODI) is a theory-based tool that measures self-care, a key strategy in the appropriate treatment of diabetes. However, despite the clinical differences between people with Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM), the psychometric properties of the SCODI were only tested in mixed samples.

Purpose

This study aims to test the psychometric performances of the SCODI in two separate groups of adults with T1DM and T2DM.

Methods

This is a secondary analysis from two previous multicentre cross-sectional observational studies involving patients with T1DM (n = 181) and T2DM (n = 540). We tested dimensionality with confirmatory factor analysis and reliability with a multidimensional model-based coefficient for every scale of the SCODI: self-care maintenance, self-care monitoring, self-care management, and self-care self-efficacy.

Results

We found that the SCODI showed the same dimensionality, with minimal variation in factor loadings for each factor and each scale among T1DM and T2DM groups. High reliability for each scale in both groups was also found (self-care maintenance: T1DM = 0.86, T2DM = 0.83; self-care monitoring: T1DM = 0.84, T2DM = 1.00; self-care management: T1DM = 0.87, T2DM = 0.86; self-care self-efficacy: T1DM = 0.88; T2DM = 0.86).

Conclusion

The SCODI can be used for measuring self-care in people with T1DM, T2DM, or mixed groups using identical scoring procedures. Considering the well-known differences between Type 1 and Type 2 diabetes diseases and patients’ characteristics, our results support the generalizability of the self-care theory on which the instrument is based.
MUNDO: protein function prediction embedded in a multispecies world
Authors: Arsenescu Victor , Devkota Kapil , Erden Mert , Shpilker Polina , Werenski Matthew , Cowen Lenore J
Published: September 2021

Motivation

Leveraging cross-species information in protein function prediction can add significant power to network-based protein function prediction methods, because so much functional information is conserved across at least close scales of evolution. We introduce MUNDO, a new cross-species co-embedding method that combines a single-network embedding method with a co-embedding method to predict functional annotations in a target species, leveraging also functional annotations in a model species network.

Results

Across a wide range of parameter choices, MUNDO performs best at predicting annotations in the mouse network, when trained on mouse and human protein–protein interaction (PPI) networks, in the human network, when trained on human and mouse PPIs, and in Baker’s yeast, when trained on Fission and Baker’s yeast, as compared to competitor methods. MUNDO also outperforms all the cross-species methods when predicting in Fission yeast when trained on Fission and Baker’s yeast; however, in this single case, discarding the information from the other species and using annotations from the Fission yeast network alone usually performs best.

Availability and implementation

All code is available and can be accessed here: github.com/v0rtex20k/MUNDO.

Supplementary information

Supplementary data are available at Bioinformatics Advances online. Additional experimental results are on our github site.
Comorbidity Increases the Risk of Invasive Meningococcal Disease in Adults
Authors: Lundbo Lene Fogt , Harboe Zitta Barrella , Sandholdt Håkon , Smith-Hansen Lars , Valentiner-Branth Palle , Hoffmann Steen , Benfield Thomas
Published: September 2021

Background

Risk of invasive meningococcal disease (IMD) is increased in patients with complement deficiency and human immunodeficiency virus (HIV) infection. Risk associated with comorbidity is not well described.

Methods

This was a nationwide adult case-control study. Cases for the period 1977–2018 were identified by the national meningococcus reference laboratory. Matched controls were identified by registry linkage. Comorbidities diagnosed prior to IMD were based on the International Classification of Diseases, Eighth or Tenth Revision. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated by logistic regression after adjustment for sex, age, and other comorbidities.

Results

We identified 1221 cases (45% male), with a median age of 45 years (interquartile range, 22–64 years). The dominant meningococcal serogroups were B (n = 738) and C (n = 337). Increased risk of IMD was associated with solid organ transplantation (SOT) (OR 40.47 [95% CI: 4.84–337.23]), hemolytic anemia (OR 7.56 [95% CI: 2.63–21.79]), renal disease (OR 2.95 [95% CI: 1.77–4.92]), liver disease (OR 2.54 [95% CI: 1.58–4.08]), cancer (OR 2.31 [95% CI: 1.85–2.89]), diabetes (OR 1.74 [95% CI: 1.27–2.39]), neurological disease (OR 1.72 [95% CI: 1.20–2.46]), and autoimmune disease (OR 1.70 [95% CI: 1.63–2.11]). Having 1, 2, and ≥3 comorbidities was associated with increased risk of IMD (ORs 1.6–3.5). Increased risk was not associated with specific serogroups.

Conclusions

This study of adults with IMD over 4 decades showed increased risk of IMD associated with renal disease, immunological disorders, liver disease, cancer, and SOT ranging from a 2- to 40-fold increased risk. Vaccination may be warranted in these populations.
Association of Poor Sleep Burden in Middle Age and Older Adults With Risk for Delirium During Hospitalization
Authors: Ulsa Ma Cherrysse , Zheng Xi , Li Peng , Gaba Arlen , Wong Patricia M , Saxena Richa , Scheer Frank A J L , Rutter Martin , Akeju Oluwaseun , Hu Kun , Gao Lei
Published: September 2021

Background

Delirium is a distressing neurocognitive disorder recently linked to sleep disturbances. However, the longitudinal relationship between sleep and delirium remains unclear. This study assessed the associations of poor sleep burden, and its trajectory, with delirium risk during hospitalization.

Methods

About 321 818 participants from the UK Biobank (mean age 58 ± 8 years [SD]; range 37–74 years) reported (2006–2010) sleep traits (sleep duration, excessive daytime sleepiness, insomnia-type complaints, napping, and chronotype—a closely related circadian measure for sleep timing), aggregated into a sleep burden score (0–9). New-onset delirium (n = 4 775) was obtained from hospitalization records during a 12-year median follow-up. About 42 291 (mean age 64 ± 8 years; range 44–83 years) had repeat sleep assessment on average 8 years after their first.

Results

In the baseline cohort, Cox proportional hazards models showed that moderate (aggregate scores = 4–5) and severe (scores = 6–9) poor sleep burden groups were 18% (hazard ratio = 1.18 [95% confidence interval: 1.08–1.28], p < .001) and 57% (1.57 [1.38–1.80], p < .001), more likely to develop delirium, respectively. The latter risk magnitude is equivalent to 2 additional cardiovascular risks. These findings appeared robust when restricted to postoperative delirium and after exclusion of underlying dementia. Higher sleep burden was also associated with delirium in the follow-up cohort. Worsening sleep burden (score increase ≥2 vs no change) further increased the risk for delirium (1.79 [1.23–2.62], p = .002) independent of their baseline sleep score and time lag. The risk was highest in those younger than 65 years at baseline (p for interaction <.001).

Conclusion

Poor sleep burden and worsening trajectory were associated with increased risk for delirium; promotion of sleep health may be important for those at higher risk.
Analyzing Birth Cohorts With the National Social Life, Health, and Aging Project
Authors: Waite Linda J , Hawkley Louise , Kotwal Ashwin A , O’Muircheartaigh Colm , Schumm L Philip , Wroblewski Kristen
Published: September 2021

Objectives

In this article, we seek to provide assistance to those who might want to use data from the National Social Life, Health, and Aging Project (NSHAP) Rounds 1–3 to compare those born in different cohorts. We outline 2 theoretical models that underlie the design of NSHAP—the life course model and the birth cohorts model—and review examples of social and political changes that may have differentially affected cohorts of older adults. Then we present 2 ways that NSHAP data might be used to compare cohorts, show examples of analyses of cohort differences in measures in NSHAP, and discuss features of the data that might affect their use for this purpose.

Methods

Round 3 of the NSHAP added a group of respondents born between 1948 and 1965, the Baby Boom. Together with data from an earlier cohort, interviewed in Rounds 1–3, these data allow analysis of birth cohorts of older adults in the United States. We show examples of some approaches.

Results

Our age-matched cohort differences approach included all observations where the respondent was aged 57–67 at the time of interview in different time periods (3,816 observations overall; 2,316 for the Silent Generation cohort and 1,500 for the Baby Boom cohort). Our second approach, age, period, and cohort effects, models the effects of age and birth year using restricted cubic splines, with one model excluding the linear effect of birth year, and the other excluding the linear effect of period. We present examples of analyses using each of these methods.

Discussion

We describe features of the NSHAP data of which researchers should be aware when conducting cohort analyses with these data.
Assessing Phlebotomy Device Preference and Specimen Quality in an Oncology Outpatient Clinic
Authors: Merrill VeRonika D , Ward Matthew D , Diaz-McNair Jovita , Pickett Elizabeth A , Duh Show-Hong , Christenson Robert H
Published: September 2021

Background

Oncology patients have frequent venipunctures, which causes scarring, making subsequent draws difficult and painful. Novel blood collection systems may decrease discomfort in patients experiencing repeat blood draws.

Methods

Oncology outpatients (n = 101; criteria excluded 12) were recruited to determine their preference for either of two blood collection systems, the 23-gauge standard BD Vacutainer Push Button Blood Collection Set (Standard Push Button system) or the 25-gauge BD Vacutainer UltraTouch Push Button Blood Collection Set (UltraTouch Push Button system). Subjects received two blinded, randomized blood draws, one with each device and just one device for each arm. Subjects subsequently rated their blinded preference for blood collection system. Specimen quality was assessed for each device with measurements for plasma hemoglobin (Shimadzu UV-1800 spectrophotometer, Shimadzu), lactate dehydrogenase, and potassium (Vitros 4600/5600 analyzer, Ortho Diagnostics).

Results

Preference for the 25-gauge UltraTouch Push Button system over the 23-gauge Standard Push Button system was significant (UltraTouch, n = 51; Standard n = 30; no preference, n = 8; P = 0.0196). Regarding sample quality, the 25-gauge UltraTouch Push Button system had significantly lower plasma hemoglobin (average 5.34 mg/dL) vs the 23-gauge Standard Push Button system (9.37 mg/dL; P < 0.0001); serum lactate dehydrogenase and potassium differences were not statistically significant.

Conclusion

Subjects in an oncology clinic preferred phlebotomy with the 25-gauge UltraTouch Push Button system, and samples using this device had less hemolysis as assessed by plasma hemoglobin.
Long-Range But Not Short-Range Attraction of Male Aedes aegypti (Diptera: Culicidae) Mosquitoes to Humans
Authors: Amos Brogan A , Hoffmann Ary A , Staunton Kyran M , Lau Meng-Jia , Burkot Thomas R , Ross Perran A
Published: September 2021

Female Aedes aegypti (Linnaeus) mosquitoes integrate multiple sensory cues to locate human hosts for blood meals. Although male Ae. aegypti swarm around and land on humans in nature to mate, direct evidence of attraction to humans is limited. Male mosquito attraction to human host cues is often undetectable in confined laboratory assays, leading to a misconception that male mosquitoes are not attracted to humans. We used semifield experiments to demonstrate robust attraction of male Ae. aegypti to humans. Human-baited traps captured up to 25% of released males within 15 min, whereas control traps without humans as bait failed to capture males. Rapid attraction to humans was further demonstrated through videography. Males swarmed around and landed on human subjects, with no activity recorded in paired unbaited controls. Finally, we confirm the lack of discernible male attraction to humans in small laboratory cages. Our experiments demonstrate that both male and female Ae. aegypti show attraction to humans, but with clear sex-specific behavioral differences at short-range. Male mosquito attraction to humans is likely to be important for mating success in wild populations and its basis should be further explored. Our results highlight the importance of arena size and assay design for mosquito behavioral research. A better understanding of host cues that attract males could help us to improve mosquito surveillance and control.
Bracken-induced increase in soil P availability, along with its high P acquisition efficiency, enables it to invade P-deficient meadows
Authors: Jelinčić Antun , Šajna Nina , Zgorelec Željka , Perčin Aleksandra
Published: September 2021

Changes in soil chemistry after invasion by bracken (Pteridium aquilinum) have been studied in heathlands, but comparable studies in meadows are lacking. We investigated if bracken invasion into P-deficient meadows alters the soil nutrient-resource pool, as well as the mechanisms behind it linked to soil processes and bracken nutrition. Furthermore, we investigated how community composition responds to differences in soil chemistry before and after the invasion. Soil and plant material sampling, along with vegetation survey, were performed during bracken peak biomass. Data analyses included analysis of variance and canonical correspondence analysis (CCA). Bracken invasion increased soil P availability, soil organic C concentration, as well as C:N, C:S and N:S ratios, while decreasing Fe and Co concentrations. Bracken pinnae were rich in P, and its rhizomes were rich in K, whereas N:P of pinnae and rhizomes was low. CCA showed contrasting abundance patterns of frequent meadow species related to P and K availability. Holcus lanatus exhibited competitive advantage under extremely low P availability. Increase in P availability under bracken may have occurred through promoting the leaching of Fe and Al. By increasing P availability for its growth and increasing N limitation for other species, bracken can gain a competitive advantage from the soil resource-niche perspective. Its ability to increase soil P availability, along with the physiological mechanisms behind its high P acquisition efficiency, seem to differentiate bracken from other species of competitive ecological strategy, which are mainly confined to nutrient-rich environments. This enabled bracken to invade P-deficient meadows.
C. auris and non-C. auris candidemia in hospitalized adult and pediatric COVID-19 patients; single center data from Pakistan
Authors: Moin Safia , Farooqi Joveria , Rattani Salima , Nasir Nosheen , Zaka Sadaf , Jabeen Kauser
Published: September 2021

We compared candidemia due to Candida auris and other non-C.auris cases in hospitalized COVID-19 patients over a period of 9 months at our institution. Candidemia cases in all admitted patients (with or without COVID-19) from April to December 2020 were identified. Electronic records were accessed to record clinical data of COVID-19 patients with candidemia. For statistical analysis, independent samples Mann-Whitney U test was used for continuous and Fisher's exact test was used for categorical variables.

A total of 26 candidemia cases (four C.auris, 22 non-C.auris) in 2438 admitted COVID-19 (10.7 per 1000 admissions) and 59 candidemia cases (six C.auris, 53 non-C.auris) in admitted non-COVID patients (8.2 per 1000 admission) were identified. The proportion of C.auris candidemia in COVID-19 and non-COVID-19 patients was 15.4 and 10%, respectively. 4/26 of COVID-19 candidemia patients were aged ≤ 15 years (10 months--15 years). Comparison of C.auris and non-C. auris candidemia cases reveal significant difference in prior antifungal exposure, present in 100% C. auris candidemia versus 27% non-C. auris candidemia patients (P-value 0.014). Although not statistically significant, C. auris candidemia patients had a longer stay in hospital before candidemia (20 vs. 9 days), higher isolation rate of multidrug resistant bacteria (100 vs. 50%), increased rate of prior colonization of Candida species (50 vs. 14%) and lower mean beta-d-glucan levels (48.73 pg/ml vs. 138.146 pg/ml). Both C. auris and non-C. auris COVID-19 patients had similar mortality rate (67 vs. 65%). A significant number of critically ill COVID-19 patients developed candidemia in our study highlighting the need for prompt diagnosis and management.

Lay summary

26 candidemia cases (4 Candida auris;22 non-C. auris) in COVID-19 patients (April-December 2020) are reported from Pakistan. Compared to non-C. auris, C. auris candidemia patients had higher prior antifungal exposure, longer hospital stay, higher rates of MDR bacteria and Candida colonization.
New Genes Interacted With Recent Whole-Genome Duplicates in the Fast Stem Growth of Bamboos
Authors: Jin Guihua , Ma Peng-Fei , Wu Xiaopei , Gu Lianfeng , Long Manyuan , Zhang Chengjun , Li De-Zhu
Published: September 2021

As drivers of evolutionary innovations, new genes allow organisms to explore new niches. However, clear examples of this process remain scarce. Bamboos, the unique grass lineage diversifying into the forest, have evolved with a key innovation of fast growth of woody stem, reaching up to 1 m/day. Here, we identify 1,622 bamboo-specific orphan genes that appeared in recent 46 million years, and 19 of them evolved from noncoding ancestral sequences with entire de novo origination process reconstructed. The new genes evolved gradually in exon−intron structure, protein length, expression specificity, and evolutionary constraint. These new genes, whether or not from de novo origination, are dominantly expressed in the rapidly developing shoots, and make transcriptomes of shoots the youngest among various bamboo tissues, rather than reproductive tissue in other plants. Additionally, the particularity of bamboo shoots has also been shaped by recent whole-genome duplicates (WGDs), which evolved divergent expression patterns from ancestral states. New genes and WGDs have been evolutionarily recruited into coexpression networks to underline fast-growing trait of bamboo shoot. Our study highlights the importance of interactions between new genes and genome duplicates in generating morphological innovation.
CeDR Atlas: a knowledgebase of cellular drug response
Authors: Wang Yin-Ying , Kang Hongen , Xu Tianyi , Hao Lili , Bao Yiming , Jia Peilin
Published: September 2021

Drug response to many diseases varies dramatically due to the complex genomics and functional features and contexts. Cellular diversity of human tissues, especially tumors, is one of the major contributing factors to the different drug response in different samples. With the accumulation of single-cell RNA sequencing (scRNA-seq) data, it is now possible to study the drug response to different treatments at the single cell resolution. Here, we present CeDR Atlas (available at https://ngdc.cncb.ac.cn/cedr), a knowledgebase reporting computational inference of cellular drug response for hundreds of cell types from various tissues. We took advantage of the high-throughput profiling of drug-induced gene expression available through the Connectivity Map resource (CMap) as well as hundreds of scRNA-seq data covering cells from a wide variety of organs/tissues, diseases, and conditions. Currently, CeDR maintains the results for more than 582 single cell data objects for human, mouse and cell lines, including about 140 phenotypes and 1250 tissue-cell combination types. All the results can be explored and searched by keywords for drugs, cell types, tissues, diseases, and signature genes. Overall, CeDR fine maps drug response at cellular resolution and sheds lights on the design of combinatorial treatments, drug resistance and even drug side effects.
Algorithmic fairness in credit scoring
Authors: Bono Teresa , Croxson Karen , Giles Adam
Published: September 2021

The use of machine learning as an input into decision-making is on the rise, owing to its ability to uncover hidden patterns in large data and improve prediction accuracy. Questions have been raised, however, about the potential distributional impacts of these technologies, with one concern being that they may perpetuate or even amplify human biases from the past. Exploiting detailed credit file data for 800,000 UK borrowers, we simulate a switch from a traditional (logit) credit scoring model to ensemble machine-learning methods. We confirm that machine-learning models are more accurate overall. We also find that they do as well as the simpler traditional model on relevant fairness criteria, where these criteria pertain to overall accuracy and error rates for population subgroups defined along protected or sensitive lines (gender, race, health status, and deprivation). We do observe some differences in the way credit-scoring models perform for different subgroups, but these manifest under a traditional modelling approach and switching to machine learning neither exacerbates nor eliminates these issues. The paper discusses some of the mechanical and data factors that may contribute to statistical fairness issues in the context of credit scoring.
ASSESSMENT OF OCCUPATIONAL RADIATION DOSES IN DIFFERENT DIAGNOSTIC, INTERVENTIONAL AND THERAPEUTIC RADIOLOGY AND MOLECULAR IMAGING SERVICES IN OMAN
Authors: Bouchareb Yassine , Al-Maimani Naema , Al-Maskery Ibtisam , Al-Zeheimi Hilal , Al-Rasbi Amaal , Al-Dhuhli Humoud , Al-Makhmari Noura , Al-Haji Amal
Published: September 2021

This study aimed at assessing occupational radiation doses in different diagnostic, interventional and therapeutic services. Personal dose equivalent, Hp(10), of 116 medical radiation workers, all with 3 y of dose records (2015–18), were collected from the TLD dosimetry service at the Sultan Qaboos University Hospital—a 700-bed tertiary care teaching hospital in Oman. The doses were measured using calibrated thermo-luminescence dosemeters (TLD-100 (LiF:Mg,Ti)). Five occupational groups, diagnostic radiology, interventional radiology, nuclear medicine, medical physicists and nurses, were considered. Average, maximum and median cumulative doses were estimated and compared against the annual dose limit (20 mSv per y) and the local dose investigation level (DIL) (6 mSv per y). Personal doses (average:maximum:median) for diagnostic radiology, interventional radiology, nuclear medicine, medical physicists and nurses group were found to be 0.05:0.90:0.00, 0.05:0.50:0.00, 1.20:7.40:0.40, 0.16:1.40:0.00 and 0.10:2.10:0.00 mSv, respectively. The findings of this study suggest, at the exception of nuclear medicine, lower DILs for all occupational groups.