bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of iohexol plasma clearance formulas vs. inulin urinary clearance for measuring glomerular filtration rate
Authors: Dubourg Laurence , Lemoine Sandrine , Joannard Brune , Chardon Laurence , de Souza Vandréa , Cochat Pierre , Iwaz Jean , Rabilloud Muriel , Selistre Luciano
Published: October 2020

Objectives

The one-compartment iohexol plasma clearance has been proposed as a reliable alternative to renal inulin clearance. However, this method’s performance depends on the formula used to calculate glomerular filtration rate (GFR). This study reports on performance comparisons between various mathematical formulas proposed for iohexol plasma clearance vs. inulin urinary clearance.

Methods

GFR was simultaneously determined by inulin and iohexol clearance in 144 participants (age: 10–84 years; glomerular filtration rate: 15–169 mL/min/1.73 m2). A retrospective cross-sectional study evaluated the performance of four formulas proposed to calculate plasma iohexol clearance (Brøchner–Mortensen, Fleming et al., Jødal–Brøchner–Mortensen, and Ng–Schwartz–Munoz). The performance of each formula was assessed using bias, precision (standard deviation of the bias), accuracy (percentage iohexol within 5, 10, and 15%), root mean square error, and concordance correlation coefficient vs. renal inulin clearance as reference.

Results

Regarding accuracy, there was no difference in root mean square error (RMSE), P5, P10, or P15 between the four formulas. The four concordance correlation coefficients (CCC) between the value from each formula and in-GFR were high and not significantly different. At in-GFR ≥90 mL/min/1.73 m2, Ng–Schwartz–Munoz formula performed slightly better than other formulas regarding median bias (−0.5; 95% CI [−3.0 to 2.0] and accuracy P15 (95.0; 95% CI [88.0–100.0]).

Conclusions

The studied formulas were found equivalent in terms of precision and accuracy, but the Ng–Schwartz–Munoz formula improved the accuracy at higher levels of in-GFR.
Re-examining ferritin-bound iron: current and developing clinical tools
Authors: Grant Erin S. , Clucas Danielle B. , McColl Gawain , Hall Liam T. , Simpson David A.
Published: October 2020

Iron is a highly important metal ion cofactor within the human body, necessary for haemoglobin synthesis, and required by a wide range of enzymes for essential metabolic processes. Iron deficiency and overload both pose significant health concerns and are relatively common world-wide health hazards. Effective measurement of total iron stores is a primary tool for both identifying abnormal iron levels and tracking changes in clinical settings. Population based data is also essential for tracking nutritional trends. This review article provides an overview of the strengths and limitations associated with current techniques for diagnosing iron status, which sets a basis to discuss the potential of a new serum marker – ferritin-bound iron – and the improvement it could offer to iron assessment.
Analytical assessment of ortho clinical diagnostics high-sensitivity cardiac troponin I assay
Authors: Kavsak Peter A. , Edge Tara , Roy Chantele , Malinowski Paul , Bamford Karen , Clark Lorna , Lamers Shana , Hill Stephen , Worster Andrew
Published: October 2020

Objectives

To analytically evaluate Ortho Clinical Diagnostics VITROS high-sensitivity cardiac troponin I (hs-cTnI) assay in specific matrices with comparison to other hs-cTn assays.

Methods

The limit of detection (LoD), imprecision, interference and stability testing for both serum and lithium heparin (Li-Hep) plasma for the VITROS hs-cTnI assay was determined. We performed Passing-Bablok regression analyses between sample types for the VITROS hs-cTnI assay and compared them to the Abbott ARCHITECT, Beckman Access and the Siemens ADVIA Centaur hs-cTnI assays. We also performed Receiver-operating characteristic curve analyses with the area under the curve (AUC) determined in an emergency department (ED)-study population (n=131) for myocardial infarction (MI).

Results

The VITROS hs-cTnI LoD was 0.73 ng/L (serum) and 1.4 ng/L (Li-Hep). Stability up to five freeze-thaws was observed for the Ortho hs-cTnI assay, with the analyte stability at room temperature in serum superior to Li-Hep with gross hemolysis also affecting Li-Hep plasma hs-cTnI results. Comparison of Li-Hep to serum concentrations (n=202), yielded proportionally lower concentrations in plasma with the VITROS hs-cTnI assay (slope=0.85; 95% confidence interval [CI]:0.83–0.88). In serum, the VITROS hs-cTnI concentrations were proportionally lower compared to other hs-cTnI assays, with similar slopes observed between assays in samples frozen <−70 °C for 17 years (ED-study) or in 2020. In the ED-study, the VITROS hs-cTnI assay had an AUC of 0.974 (95%CI:0.929–0.994) for MI, similar to the AUCs of other hs-cTn assays.

Conclusions

Lack of standardization of hs-cTnI assays across manufacturers is evident. The VITROS hs-cTnI assay yields lower concentrations compared to other hs-cTnI assays. Important differences exist between Li-Hep plasma and serum, with evidence of stability and excellent clinical performance comparable to other hs-cTn assays.
Diagnostic and prognostic role of presepsin in patients with cirrhosis and bacterial infection
Authors: Ferrarese Alberto , Frigo Anna Chiara , Mion Monica Maria , Plebani Mario , Russo Francesco Paolo , Germani Giacomo , Gambato Martina , Cillo Umberto , Cattelan Annamaria , Burra Patrizia , Senzolo Marco
Published: October 2020

Objectives

Serum biomarkers have suboptimal accuracy for the early diagnosis of bacterial infection (BI) in cirrhosis. The aim of the study was to evaluate the diagnostic and prognostic accuracy of presepsin (PSP) in a cohort of hospitalized patients with cirrhosis.

Methods

All adult cirrhotics admitted between 03.2016 and 06.2019 were consecutively evaluated. PSP was measured using chemiluminescent enzyme immunoassay, and its accuracy was compared with that of common biomarkers.

Results

A total of 278 cirrhotic patients for a total of 448 hospitalizations were prospectively collected. Prevalence of BI at admission was 28.3%. Median (range) Log10PSP in the whole cohort was 2.83 (2.48–3.19) ng/L, significantly higher in patients with BI than in patients without (p<0.001). For a cutoff value of 2.87 ng/L, Log10PSP showed sensitivity, specificity and AUC-ROC of 0.66 (95% CI 0.57–0.74), 0.63 (95% CI 0.57–0.68) and 0.69 (95% CI 0.63–0.73), lower than that of C-reactive protein (p=0.002), but similar to procalcitonin (p=0.18) Patients with BI at hospitalization had higher probability of 28-day mortality (sub-hazard ratio [sHR] 2.65;95% CI 1.49–4.70; p=0.001). At multivariate Cox’s regression analysis, Log10PSP (sHR 2.4; 95% CI 1.22–4.82; p=0.01) together with age and severity of liver disease, was an independent predictor of short-term mortality.

Conclusions

PSP shows low diagnostic accuracy for BI in cirrhosis, but it is an independent predictor of short-term mortality. PSP may be a biomarker of systemic inflammation, commonly seen in end-stage liver disease.
Development, evaluation, and validation of machine learning models for COVID-19 detection based on routine blood tests
Authors: Cabitza Federico , Campagner Andrea , Ferrari Davide , Di Resta Chiara , Ceriotti Daniele , Sabetta Eleonora , Colombini Alessandra , De Vecchi Elena , Banfi Giuseppe , Locatelli Massimo , Carobene Anna
Published: October 2020

Objectives

The rRT-PCR test, the current gold standard for the detection of coronavirus disease (COVID-19), presents with known shortcomings, such as long turnaround time, potential shortage of reagents, false-negative rates around 15–20%, and expensive equipment. The hematochemical values of routine blood exams could represent a faster and less expensive alternative.

Methods

Three different training data set of hematochemical values from 1,624 patients (52% COVID-19 positive), admitted at San Raphael Hospital (OSR) from February to May 2020, were used for developing machine learning (ML) models: the complete OSR dataset (72 features: complete blood count (CBC), biochemical, coagulation, hemogasanalysis and CO-Oxymetry values, age, sex and specific symptoms at triage) and two sub-datasets (COVID-specific and CBC dataset, 32 and 21 features respectively). 58 cases (50% COVID-19 positive) from another hospital, and 54 negative patients collected in 2018 at OSR, were used for internal-external and external validation.

Results

We developed five ML models: for the complete OSR dataset, the area under the receiver operating characteristic curve (AUC) for the algorithms ranged from 0.83 to 0.90; for the COVID-specific dataset from 0.83 to 0.87; and for the CBC dataset from 0.74 to 0.86. The validations also achieved good results: respectively, AUC from 0.75 to 0.78; and specificity from 0.92 to 0.96.

Conclusions

ML can be applied to blood tests as both an adjunct and alternative method to rRT-PCR for the fast and cost-effective identification of COVID-19-positive patients. This is especially useful in developing countries, or in countries facing an increase in contagions.
The clinical relevance of anti-dsDNA antibodies determined by the Elia™ dsDNA assay in patients with negative indirect immunofluorescence on the HEp-2 cell
Authors: Robier Christoph , Haas Maximiliane , Quehenberger Franz
Published: October 2020

Objectives

Data on the clinical importance of the detection of anti-dsDNA antibodies in patients with negative indirect immunofluorescence on the HEp-2 cell (IIF) are sparse and are especially not available for all common commercially available assays. This study aimed to assess the clinical significance of anti-dsDNA antibodies determined by the Elia™ dsDNA assay in patients with negative IIF.

Methods

We retrospectively examined the medical records of 234 consecutive subjects with detectable anti-dsDNA antibodies determined by the Elia™ dsDNA assay.

Results

A total of 124 subjects with detectable anti-dsDNA autoantibodies were IIF-negative, but yielded positive or borderline results in the Elia™ CTD screen assay for antinuclear antibodies (ANA). Within this group, 6/49 IIF-negative patients (12%) with ANA-associated systemic autoimmune rheumatic disorders (AASARD) and 118/185 subjects (64%) with various other diseases (Non-AASARD) were identified. There was no statistically significant difference with regard to the concentrations of anti-dsDNA antibodies (p=0.53) between the AASARD and the Non-AASARD group. Within the AASARD group, four patients diagnosed with systemic lupus erythematosus (SLE, treated), discoid lupus erythematosus (untreated), indetermined connective tissue disease (untreated) and polymyositis (treated) had positive anti-dsDNA autoantibodies, whereas two patients with treated SLE, thereby one in remission, had borderline concentrations of anti-dsDNA antibodies.

Conclusions

Our findings suggest that the detection of anti-dsDNA antibodies in IIF-negative patients can be of clinical relevance in some cases. Our results further support the combined use of IIF and solid-phase assays in screening algorithms for ANA, in order to avoid overlooking potentially important autoantibody entities.
The use of preanalytical quality indicators: a Turkish preliminary survey study
Authors: Orhan Bagnu , Sonmez Derya , Cubukcu Hikmet Can , Zengi Oguzhan , Ozturk Emre Humeyra , Cinaroglu Ipek , Keles Murat , Gumus Alper , Coskun Cihan
Published: October 2020

Objectives

The utilization of reliable quality indicators (QIs) proven to be suitable for monitoring and improvement tools is one of the best choices to minimize of the risk of errors in all laboratory processes called as total testing process (TTP). In 2008, a Working Group “Laboratory Errors and Patient Safety” (WG-LEPS) established by International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) developed the Model of Quality Indicators (MQI) complying with requirements of the ISO 15189:2012 standard for laboratory accreditation. They have also been dealing with harmonizing the QIs in most laboratories worldwide since then. The present study was set out to investigate the frequency of using IFCC WG-LEPS’ pre-QIs by Turkish laboratories and to assess the conformity of them, by taking into account Turkey’s conditions.

Methods

A survey consisting nine questions was applied in 81 laboratories using SurveyMonkey.

Results

According to the survey results, most of the laboratories reported they have used pre-QIs in the quality standards of health prepared by Turkish Ministry of Health (MOH). A part of IFCC WG-LEPS’ pre-QIs were being utilized by more than 80% of the laboratories, the rest of which only used by 10% of laboratories.

Conclusions

The majority of the medical laboratories have been using the pre-QIs included in the guidelines of Quality Standards prepared by the MOH. The pre-QIs are partially compatible with IFCC WG-LEPS’ pre-QIs. The definitions of IFCC WG-LEPS’ pre-QIs may also be revised to make them more clear and understandable by IFCC WG-LEPS. The insufficiency of Health Information Management Systems (HIMS) limits the use of pre-QIs proposed by IFCC WG-LEPS. Finally, the education of relevant personnel about the use of HIMS and pre-QIs is very crucial to harmonize and to extend the use of IFCC WG-LEPS’ pre-QIs in Turkish medical biochemistry laboratories.
The Academy of the European Federation of Clinical Chemistry and Laboratory Medicine and the European Register of Specialists in Laboratory Medicine: guide to the Academy and the Register, version 4 – 2020
Authors: Wieringa Gijsbert , Jassam Nuthar , Homsak Evgenija , Rako Ivana , Racek Jaroslav
Published: October 2020

The 4th version of the guide to the Register for European Specialists in Laboratory Medicine (EuSpLM) established by the European Communities Confederation of Clinical Chemistry and Laboratory Medicine describes the transfer of the register to the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) in 2016, the extension in 2018 of the Register beyond the European Union to Europe and the benefits of membership of the EFLM Academy to which the Register transferred on the Academy’s launch in 2019. The Academy offers EuSpLM registrants access to benefits that include reduced registration rates at selected conferences and free subscription to Clinical Chemistry and Laboratory Medicine. With effect from 2020 eligibility was extended to anyone with an interest in laboratory medicine. The updated guide describes the electronically driven processes for individual membership and block enrolment from national societies/organisations, and the stepping stones to recognition as an EuSpLM within the Academy. Whilst eligibility for recognition as an EuSpLM remains largely unchanged new expectations across Europe in education, training, professional regulation and qualifications are reflected in updated criteria. The continuing driver for establishing the Academy and growing the EFLM Register reflects the federation’s leadership role in the harmonisation of high quality education and training for those with an interest in laboratory medicine as well as ongoing initiatives to establish a Common Training Framework for Specialists in Laboratory Medicine under EU Directive 2013/55/EC (The Recognition of Professional Qualifications).
Advances in electrical stimulation-based therapy for tinnitus
Authors: Olze Heidi , Vater Jana , Szczepek Agnieszka J. , Reich Uta , Gräbel Stefan , Uecker Florian Cornelius
Published: October 2020

Tinnitus is a phantom percept of noise heard only by the affected person. The principal problem of persons suffering from tinnitus is the inability to deflect their attention from the phantom sound, resulting in insomnia and problems with concentration, followed by significant health issues. To date, no therapy would relieve patients from the phantom sound. Instead, commonly used therapeutic approaches for tinnitus aim primarily at the reduction of tinnitus-induced distress and are based on various tinnitus habituation methods. Our project aims to quench the tinnitus percept using an implant. To develop such an implant, this research group joined the INTAKT network initiated by the German Federal Ministry of Education and Research and dedicated to the development of smart implants. During this still ongoing, prospective clinical study, the efficacy of two protocols using electrical stimulation is assessed for tinnitus silencing. The electrical stimulation used in the presented study is non-invasive and applied on three consecutive days in the form of short sessions. In a sample of 48 subjects, following three stimulation sessions, 48% of patients reported a significant reduction of tinnitus loudness; 10% reported a brief increase of tinnitus loudness, and 42% stated no change. In one case, the first course of stimulation led to the total distinguishing of tinnitus. On average, the stimulation did not affect the grade of tinnitus-induced distress during the time of measurement. Our current results prompt us to broaden our investigations, expand the subject sample, and further optimize the stimulation conditions.
Wireless retina implant with optical energy supply
Authors: Velten Thomas , Knoll Thorsten , Stracke Frank , Le Harzic Ronan , Jaeger Tino , Rammensee Michael , Kurz Oliver , Klesy Stephan , Januschowski Kai , Sermeus Loic , Szurman Peter , Olsommer Yves , Hoffmann Klaus-Peter
Published: October 2020

We present the first results of work towards a foil-based epiretinal prosthesis that can stimulate retinal cells. The prosthesis receives trigger signals and energy in the form of high intensity infrared radiation. Array-like silicon photodiodes with attached thin film electrodes convert the received infrared light into electrical stimulation signals, which are intended to stimulate ganglion cells. The photodiodes are arranged like stones in a mosaic on an only 10 µm thin and thus flexible polymer foil. Like this, the prosthesis can adapt to the curved shape of the eye and will have close contact with the retina.

The photodiode array is fabricated on silicon wafers. Etched trenches guarantee the electrical separation between the individual photodiodes and pixels. Spectral sensitivities of backside-illuminated photodiodes were measured for wafers thinned to different thicknesses. The thin polymer foil is realized by spin coating polyimide on the photodiode array followed by imidization. Via holes are etched into the polyimide film for contacting the pads of the photodiodes. First spin coating tests were performed using silicon wafers without photodiodes but with metal pads and with etched trenches to simulate the gap between individual photodiodes.

Although the thickness of the spin-coated polyimide layer was very inhomogeneous, we succeeded in realizing vias for connecting contact pads by thin film gold tracks crossing deep trenches. The realized via holes had inclined sidewalls as desired. Electrical measurements showed sufficient electrical contact between two connected pads.
Camera-based climbing analysis for a therapeutic training system
Authors: Richter Julia , Beltrán Raul Beltrán , Heinkel Ulrich
Published: October 2020

In view of therapeutic applications, climbing motion analysis has gained increased importance to avoid movements that are prone to cause injuries and to motivate the climber by means of gamification. To date, there remains need to investigate analysis methods for feedback generation that do not require body contact and that can be easily integrated in the climbing setup. Therefore, this study proposes an camera-based approach for contact-less motion analysis that localises the climber’s centre of mass (COM) and derives relevant parameters, such as fluency, force and distance to the wall, from the temporal COM analysis.
Real-time classification of hand movements as a basis for intuitive control of grasp neuroprostheses
Authors: Amelin Dmitry , Potapov Ivan , Audí Josep Cardona , Kogut Andreas , Rupp Rüdiger , Ruff Roman , Hoffmann Klaus-Peter
Published: October 2020

This paper reports on the evaluation of recurrent and convolutional neural networks as real-time grasp phase classifiers for future control of neuroprostheses for people with high spinal cord injury. A field-programmable gate array has been chosen as an implementation platform due to its form factor and ability to perform parallel computations, which are specific for the selected neural networks. Three different phases of two grasp patterns and the additional open hand pattern were predicted by means of surface Electromyography (EMG) signals (i.e. Seven classes in total). Across seven healthy subjects, CNN (Convolutional Neural Networks) and RNN (Recurrent Neural Networks) had a mean accuracy of 85.23% with a standard deviation of 4.77% and 112 µs per prediction and 83.30% with a standard deviation of 4.36% and 40 µs per prediction, respectively.
The status quo of the visual turn in public relations practice
Authors: Wiesenberg Markus , Verčič Dejan
Published: October 2020

While most research in public relations and strategic communication concentrates on textual elements, this contribution shifts the focus to the growing importance of visual elements. The theoretical background is based on visual theory and the concept of strategic mediatization. By using a large-scale quantitative survey among 3,387 European communication professionals, this study is the first empirical evidence of communication professionals’ perspectives concerning visual communication. Therefore, the paper empirically demonstrates a visual turn in strategic communication. Although practitioners have been using visual elements since the very beginnings of their trade, only a minority guide these activities through a sound management process. This calls for a deeper consideration of visual communication management in practice and visual public relations research in academia.
Does fake news lead to more engaging effects on social media? Evidence from Romania
Authors: Corbu Nicoleta , Bârgăoanu Alina , Buturoiu Raluca , Ștefăniță Oana
Published: October 2020

This study examines the potential of fake news to produce effects on social media engagement as well as the moderating role of education and government approval. We report on a 2x2x2 online experiment conducted in Romania (N=813), in which we manipulated the level of facticity of a news story, its valence, and intention to deceive. Results show that ideologically driven news with a negative valence (rather than fabricated news or other genres, such as satire and parody) have a greater virality potential. However, neither the level of education nor government approval moderate this effect. Additionally, both positive and negative ideologically driven news stories enhance the probability that people will sign a document to support the government (i. e., potential for political engagement on social media). These latter effects are moderated by government approval: Lower levels of government approval lead to less support for the government on social media, as a consequence of fake news exposure.
Effect of pH on the degradation kinetics of a Mg–0.8Ca alloy for orthopedic implants
Authors: Mohamed Aya , Breitinger Hans-Georg , El-Aziz Ahmed M.
Published: October 2020

One of the promising applications of magnesium and magnesium alloys is their use as biodegradable implants in biomedical applications. The pH around an orthopedic implant greatly affects the degradation kinetics of biodegradable Mg–Ca alloys. At the location of a fracture, local pH changes, and this has to be considered in the optimization of implant materials. In this study, the effect of the pH of a physiological buffer on degradation of a Mg–0.8Ca alloy was studied. The pH of Hank’s balanced salt solution (HBSS) was adjusted to 1.8, 5.3 and 8.1. Degradation of a Mg–0.8Ca implant was tested using immersion test and electrochemical techniques. Immersion tests revealed an initial weight gain for all samples followed by weight loss at extended immersion time. Weight gain was highest at acidic pH (1.8) and lowest at alkaline pH (8.1). This was in agreement with results from electrochemical polarization tests where the degradation rate was highest (7.29 ± 2.2 mm/year) at pH 1.8 and lowest (0.31 ± 0.06 mm/year) in alkaline medium of pH 8.1. The pH of all HBSS buffers except the most acidic (pH 1.8) reached a steady state of ∼pH 10 at the end of the two-month immersion period, independent of the initial pH of the solution. Corrosion products formed on the sample surfaces were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-ray diffractometry (XRD), revealing the formation of magnesium and calcium phosphates with distinct morphologies that were different for each of the pH conditions. Thus, pH of physiological buffers has a significant effect on the degradation and corrosion of Mg–Ca alloys used for biomedical applications.
Numerical simulation of the effect of baffle cut and baffle spacing on shell side heat exchanger performance using CFD
Authors: Gaikwad Swanand , Parmar Ashish
Published: October 2020

Heat exchangers possess a significant role in energy transmission and energy generation in most industries. In this work, a three-dimensional simulation has been carried out of a shell and tube heat exchanger (STHX) consisting of segmental baffles. The investigation involves using the commercial code of ANSYS CFX, which incorporates the modeling, meshing, and usage of the Finite Element Method to yield numerical results. Much work is available in the literature regarding the effect of baffle cut and baffle spacing as two different entities, but some uncertainty pertains when we discuss the combination of these two parameters. This study aims to find an appropriate mix of baffle cut and baffle spacing for the efficient functioning of a shell and tube heat exchanger. Two parameters are tested: the baffle cuts at 30, 35, 40% of the shell-inside diameter, and the baffle spacing’s to fit 6,8,10 baffles within the heat exchanger. The numerical results showed the role of the studied parameters on the shell side heat transfer coefficient and the pressure drop in the shell and tube heat exchanger. The investigation shows an increase in the shell side heat transfer coefficient of 13.13% when going from 6 to 8 baffle configuration and a 23.10% acclivity for the change of six baffles to 10, for a specific baffle cut. Evidence also shows a rise in the pressure drop with an increase in the baffle spacing from the ranges of 44–46.79%, which can be controlled by managing the baffle cut provided.
Decolorization of Reactive Black B from wastewater by electro-coagulation: optimization using multivariate RSM and ANN
Authors: Gautam Kajal , Verma Rishi K. , Kamsonlian Suantak , Kumar Sushil
Published: October 2020

The present study is aimed to model and optimize the electrocoagulation (EC) process with five important parameters for the decolorization of Reactive Black B (RBB) from simulated wastewater. A multivariate approach, response surface methodology (RSM) together with central composite design (CCD) is used to optimize process parameters such as pH (5–9), electrode gap (0.5–2.5 cm), current density (2.08–10.41 mA/cm2), process time (10–30 min), and initial dye concentration (100–500 mg/l). The predicted percentage decolorization of dye is obtained as 97.21% at optimized conditions: pH (6.8), gapping (1.3 cm), current density (8.32 mA/cm2), time (23 min), and initial dye concentration (200 mg/L), which is very close to experimental percent decolorization (98.41%). The statistical analysis of variance (ANOVA) is performed to evaluate the quadratic model (RSM), and shows good fit of experimental data with coefficient of determination R2 >0.93. An Artificial Neural Network (ANN) is also used to predict the percentage decolorization and gives overall 94.96% which shows performance accuracy between the predicted and actual value of decolorization. The additional considerations of operating cost and current efficiency are also taken care to show the efficacy of EC process with mathematical tool. The sludge characteristics are determined by FE-SEM/EDX.
Predicting Higher Education Grades using Strategies Correcting for Panel Attrition
Authors: Giese Marco
Published: October 2020

This study aims to forecast the final grade of the first higher education degree which can be of considerable interest for higher education institutions to implement early warning systems, students themselves, or potential employers. The analysis is based on the National Education Panel Study (NEPS), a large German dataset covering many aspects of students’ (educational) life. Since panel attrition concerns 35% of participants the Heckman correction and the inverse probability weight (IPW) estimator are used to reduce the estimation bias. A distinction is made between two scenarios, excluding dropout students and including them with a grade of 5.0. Some predictors reveal significant parameter estimates in the first but not in the second scenario, or vice versa, which means that dropout and study performance is not driven by the same variables. To get an early prediction of grades only variables of a pre-university episode were included in the first step. Afterward, variables of the early study phase are included. For the IPW estimator, the R2 improves from 0.202 to 0.593 (dropouts included) when adding the additional variables. The best predictors are the grades at secondary school, grades in the first exams, and the type of institution.
𝑞-Tricomi functions and quantum algebra representations
Authors: Riyasat Mumtaz , Nahid Tabinda , Khan Subuhi
Published: October 2020

The quantum groups nowadays attract a considerable interest of mathematicians and physicists.
The theory of q-special functions has received a group-theoretic interpretation using the techniques of quantum groups and quantum algebras.
This paper focuses on introducing the q-Tricomi functions and 2D q-Tricomi functions through the generating function and series expansion and for the first time establishing a connecting relation between the q-Tricomi and q-Bessel functions.
The behavior of these functions is described through shapes, and the contrast between them is observed using mathematical software.
Further, the problem of framing the q-Tricomi and 2D q-Tricomi functions in the context of the irreducible representation

(
ω
)

{(\omega)}

of the two-dimensional quantum algebra

ℰ
q

⁢

(
2
)

{\mathcal{E}_{q}(2)}

is addressed, and certain relations involving these functions are obtained.
2-Variable 1-parameter q-Tricomi functions and their relationship with the 2-variable 1-parameter q-Bessel functions are also explored.
Water vapour sorption behaviour and physico-mechanical properties of methyl methacrylate (MMA)- and MMA–styrene-modified batai (Paraserianthes falcataria) wood
Authors: Anwar Uyup Mohd Khairun , Sahari Siti Hanim , Jalaludin Zaihan , Husain Hamdan , Lee Seng Hua , Yusoh Alia Syahirah
Published: October 2020

The purpose of this study was to determine the applicability of methyl methacrylate (MMA) and MMA–styrene in treating batai (Paraserianthes falcataria) wood. The effectiveness of the treatment was evaluated based on Fourier transform infrared spectroscopy (FTIR) analysis, physico-mechanical properties of the treated wood, and moisture sorption isotherm using dynamic vapour sorption (DVS) apparatus. Physico-mechanical properties of the modified batai wood were improved. The MMA-treated batai wood showed better improvement in terms of physical and mechanical properties compared to the MMA–styrene-treated batai wood. The equilibrium moisture content (EMC) for untreated batai wood was higher than that of treated samples. At 95% RH, the EMC for untreated batai wood was 20.7%, whereas the EMC for MMA- and MMA–styrene-treated samples was 7.9 and 8.8%, respectively. The findings indicate that the modified batai wood absorbed less moisture compared to the untreated batai wood. Moreover, the untreated batai wood had larger hysteresis loop than the treated batai wood. The highest hysteresis value was observed at 80% RH for untreated batai wood (3.8%), followed by MMA–styrene-treated batai wood (1.7%) and MMA-treated batai wood (1.2%). Both MMA and MMA–styrene proved to be effective treatments for batai wood because they reduced its hygroscopicity.
Enhancement of the physical and mechanical properties of wood using a novel organo-montmorillonite/hyperbranched polyacrylate emulsion
Authors: Xu Jianfeng , Li Xiaoyan , Long Ling , Liu Ru
Published: October 2020

In this work, a novel waterborne hyperbranched polyacrylate (HBPA) dispersed organo-montmorillonite (OMMT) emulsion was synthesized and used for the treatment of wood in a vacuum environment in order to enhance the physical and mechanical properties of the wood. The sapwood of Cathay poplar (Populus cathayana Rehd.) and Radiata pine (Pinus radiata D.Don) were used as the samples for experimentation. The results showed that the physical and mechanical properties of the wood improved significantly due to the successful penetration of the OMMT and HBPA into the wood cell wall. From it was also observed that OMET completely exfoliated from the HBPA matrix and formed a hydrophobic film covering on the inside walls of the cell lumen. Further, it was observed that the poplar sample displayed better mechanical properties than the pine sample because the pine has a more compact structure when compared to poplar and contains rosin. Furthermore, it was also observed that the mechanical properties of the modified wood sample gradually improved with an increase in the concentration of the emulsion. However, excessive concentration (>4 wt%) did not lead to further improvement.
Demonstration of the applicability of visible and near-infrared spatially resolved spectroscopy for rapid and nondestructive wood classification
Authors: Ma Te , Inagaki Tetsuya , Tsuchikawa Satoru
Published: October 2020

Although visible and near-infrared (Vis-NIR) spectroscopy can rapidly and nondestructively identify wood species, the conventional spectrometer approach relies on the aggregate light absorption due to the chemical composition of wood and light scattering originating from the physical structure of wood. Hence, much of the work in this area is still limited to further spectral pretreatments, such as baseline correction and standard normal variate to reduce the light scattering effects. However, it should be emphasized that the light scattering rather than absorption in wood is dominant, and this must be effectively utilized to achieve highly accurate and robust wood classification. Here a novel method based on spatially resolved diffuse reflectance (wavelength range: 600–1000 nm) was demonstrated to classify 15 kinds of wood. A portable Vis-NIR spectral measurement system was designed according to previous simulations and experimental results. To simplify spectral data analysis (i.e., against overfitting), support vector machine (SVM) model was constructed for wood sample classification using principal component analysis (PCA) scores. The classification accuracies of 98.6% for five-fold cross-validation and 91.2% for test set validation were achieved. This study offers enhanced classification accuracy and robustness over other conventional nondestructive approaches for such various kinds of wood and sheds light on utilizing visible and short-wave NIR light scattering for wood classification.
A model to predict the kinetics of mass loss in wood during thermo-vacuum modification
Authors: Allegretti Ottaviano , Cuccui Ignazia , Terziev Nasko , Sorini Laerte
Published: October 2020

Mass loss (ML) of wood caused by thermal degradation is one of the most important features of the thermal treatments and referred to as an indicator of intensity and quality of the process. The ML is proportional to the quantity of the effective heat power exchanged during the treatment process, represented by the area of the temperature profile versus time during the process. In this paper a model for the ML prediction based on the relative area was discussed. The model proposed an analytical solution to take into account the non-linear trend of ML when plotted versus temperature and time as observed in isothermal experiments. The model was validated comparing calculated and measured final ML of samples treated during thermal modification tests with different temperature profiles. The results showed that the relative area calculated in a transformed time-temperature space improves the correlation with the measured ML.
Effect of Artemisia absinthium ethanolic extract on oxidative stress markers and the TLR4, S100A4, Bax and Bcl-2 genes expression in the kidney of STZ-induced diabetic rats
Authors: Bagheri Fatemeh , Amri Jamal , Salehi Mehdi , Karami Hadi , Alimoradian Abbas , Latifi Seied Amirhossein
Published: October 2020

Objectives

The present study was conducted to examine antidiabetic effects of Artemisia absinthium ethanolic extract [A. absinthium] and to investigate its effects on oxidative stress markers and the expression of TLR4, S100A4, Bax and Bcl-2 genes in the kidney of STZ-induced diabetic rats.

Methods

Thirty six rats (weight 200–250 g) were randomly divided into diabetes and control groups. Induction of diabetes was performed using STZ (55 mg/kg.bw). Biochemical parameters and oxidative stress markers (SOD and MDA) were measured using spectrophotometry after 60 days of treatment. The expression of TLR4, S100A4, Bax and Bcl-2 were analyzed by real-time PCR. One-way analysis of variance (ANOVA) and Bonferroni post hoc test were used to compare the data.

Results

Diabetes significantly impairs the serum fasting blood glucose (FBG), lipid profile, urea, creatinine and albumin. At the end of treatment with A. absinthium extract, these parameters were close to the normal range. The results showed that the A. absinthium extract significantly decreased the kidney expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress markers (SOD and MDA) in the kidney tissues of treated rats. Also, all of these beneficial effects of the A. absinthium were dose-dependent.

Conclusions

The extract of A. absinthium possesses antidiabetic effects. A. absinthium decreased the expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress. Therefore, this herbal extract can be used as an adjuvant treatment for diabetic complications.
Daily peak-based short-term demand prediction using backpropagation combined to chi-squared distribution
Authors: Kebir Nisrine , Lamallam Abdessamad , Moussa Abdelqoddous
Published: October 2020

An efficient and economic scheduling of power plants relies on an accurate demand forecast especially for the short-term due to its tight relation to power markets and trading operations in interconnected power systems. A slight deviation of load prediction from real demand could engender the start-up of a conventional power station which could be either time-consuming or requiring expensive combustible, a deviation that could interfere as well with renewables intermittency and demand response strategies. Hence, load forecasting still a challenging subject because of the various transformations that the energy sector undergoes and that directly impact the demand profile shape. Therefore, conceiving dynamic load demand forecast approaches will permit utilities save money in different vertical structures and regulation schemes. In this paper, we propose a novel approach for short-term demand prediction valid for normal and special days to address the impact of climate changes along with events occurrence on forecast accuracy. This approach is based on the prediction of hourly loads, established on the daily peak load prediction using backpropagation combined to chi-squared method for weighting historical data to enhance the training process. Obtained results from extensive testing on the Moroccan’s power system confirm the strength of the developed approach, that improved the forecast accuracy by a range of 1.1–4% compared to the existing methods.
Assessment method of comprehensive energy saving potential of distribution network considering source-load power uncertainty
Authors: Yang Jialin , Li Huina , Li Jizhou , Hou Bin , Zhen Yong
Published: October 2020

The comprehensive energy-saving potential evaluation method of the energy-saving schemes of a distribution network considering the power uncertainty of source and load is studied in this paper. The K-means clustering method is firstly employed to extract typical scenarios of distribution network, and the forward-push back method is used to calculate the power flow in typical scenarios, then energy-saving reconstruction schemes are formulated according to the power flow calculation results. A comprehensive energy saving potential evaluation index system that consists the improvement rate of network loss, line loss rate, transformer loss rate, annual electricity saving cost, annual equipment investment cost, annual maintenance cost and voltage quality improvement rate is built, and the comprehensive evaluation method based on DEMATEL-ANP-TOPSIS mixed decision model is used to evaluate the comprehensive energy-saving potential of the energy-saving reconstruction schemes regarding the index system. Finally, the optimal reconstruction scheme is selected based on the evaluation results of energy saving potential in multiple scenarios. The effectiveness of the proposed method is verified by an example in IEEE-33 node distribution network.
A computational method for time fractional partial integro-differential equations
Authors: Mojahedfar M. , Tari Abolfazl , Shahmorad S.
Published: October 2020

In this paper, a class of time fractional partial integro-differential equations (FPIDEs) with initial conditions is studied. Some operational matrices are used to reduce a FPIDE problem to a system of algebraic equations with special properties. The resulted system is solved to give an approximate solution to the problem. Error estimation is also discussed for the approximate solution. Finally, some numerical examples are given to show the accuracy of the proposed method.
A novel GNSS deformation feature extraction method based on ensemble improved LMD threshold denoising
Authors: Fan Qian , Zhu Yiqun
Published: October 2020

In order to solve the problem that the moving span of basic local mean decomposition (LMD) method is difficult to choose reasonably, an improved LMD method (ILMD), which uses three cubic spline interpolation to replace the sliding average, is proposed. On this basis, with the help of noise aided calculation, an ensemble improved LMD method (EILMD) is proposed to effectively solve the modal aliasing problem in original LMD. On the basis of using EILMD to effectively decompose the data of GNSS deformation monitoring series, GNSS deformation feature extraction model based on EILMD threshold denoising is given by means of wavelet soft threshold processing mode and threshold setting method in empirical mode decomposition denoising. Through the analysis of simulated data and the actual GNSS monitoring data in the mining area, the results show that denoising effect of the proposed method is better than EILMD, ILMD and LMD direct coercive denoising methods. It is also better than wavelet analysis denoising method, and has good adaptability. This fully demonstrates the feasibility and effectiveness of the proposed method in GNSS feature extraction.
Foreign Aid and Adolescent Fertility Rate: Cross-Country Evidence
Authors: Zhuang Hong , Wang Miao , Daniels Joseph
Published: October 2020

This study examines the role of official development assistance (ODA) in affecting adolescent fertility rates in low- and middle-income countries. Approximately 95% of adolescent births occur in middle- and low-income countries, and the average adolescent fertility rate in low-income countries is five times higher than in high-income countries. Aid donors typically pursue multiple objectives when providing development aid, many of which can go beyond changes in per capita GDP and include human capital factors such as adolescent fertility and infant mortality. Using data over the period from 1995 to 2015, our results suggest that total ODA has a beneficial impact by lowering the adolescent fertility rate either directly or through the channel of income growth. Our results also show that this beneficial effect on the adolescent fertility rate is stronger in low-income countries than in middle-income countries. Findings based on sectoral aid suggest that health aid has a stronger effect than aid in other sectors.
Numerical analysis of photonic crystal fibre with high birefringence and high nonlinearity
Authors: Agbemabiese Patrick Atsu , Akowuah Emmanuel Kofi
Published: October 2020

A four-ring microstructure photonic crystal fibre with a descending air hole ring cladding is presented. Numerical analysis of the structure is done using full vectorial finite element method with perfectly matched layer (PML) boundary condition. It is demonstrated that it is possible to achieve at 1.55 µm confinement loss of 2.767 × 10−5 dB/m, birefringence of 0.00346 and a nonlinear co-efficient of 41.77 km−1 W−1. Also, chromatic dispersion realised suggests a tuneable zero dispersion at 0.9–1.1 µm wavelength range.
An investigation of 16-QAM signal transmission over turbulent RoFSO link modeled by gamma–gamma distribution
Authors: Tripathi Abhishek , Gupta Shilpi , Mandloi Abhilash , Soni Gireesh G
Published: October 2020

This paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation–based radio over free space optical communication system. Here, 60 GHz radio frequency–modulated signal is propagated through a 1550-nm free space optical link. The gamma–gamma distribution is used for the channel modeling of weak to strong atmospheric turbulence. The reported constellation plots and eye patterns are attributed to impairment factors in adverse conditions of atmosphere. The evaluation is carried out that the variation in average error vector magnitude in the range of 1.45–1.63% and equivalent symbol error rate of 0.019–0.023 are obtained for a clear atmosphere compared to the turbulent link of 0.2–1 km, respectively.
High speed optical switching gain based EDFA model with 30 Gb/s NRZ modulation code in optical systems
Authors: Eid Mahmoud M. A. , Rashed Ahmed Nabih Zaki , Kurmendra
Published: October 2020

This study presents high speed optical switching gain based Erbium doped fiber amplifier model. By using the proposed model the optical fiber loss can be minimized. The system is stabilized with the power budget of 25.875 mW a long 75 km as a length of optical fiber in this study can be verified. The modulation rate of 10 Gb/s can be upgrade up to reach 30 Gb/s. The suitable power for the optical transmitter is −2.440 dBm and NRZ modulation code is verified. The receiver sensitivity can be upgraded with the minimum bit error rate and max Q factor are 1.806 e−009 and 5.899.