Changes In Cell Parameters Research Articles

Aliovalent Doping of Niobium and Tantalum Pentoxide as Potential Alternative Support Material for Fuel Cell Catalysts

AbstractAs the usually used Carbon Blacks (CB) as support materials in fuel cell catalysts are thermodynamically unstable, alternative supports with high chemical stability and electrical conductivity are to be found. After the investigation of Nb and Ta‐doped SnO2 in an earlier publication, which revealed interesting conductivity properties, we expanded our portfolio of mutual doping of elements of stable oxides into the oxides of the others by reporting here on the Sn, Hf and W‐doping as guests into the base oxides Nb2O5 and Ta2O5. The changes in unit cell parameters as indicators for the doping success were investigated in the doping range of x=0–10 mol % guest fraction. From a complete solubility of the guest ions in case of Hf and W‐doping in the base oxides to a limited solubility in case of Sn‐doping, a whole spectrum of different results was obtained. Additional insight came from UV/vis spectroscopic investigations in diffuse reflectance as well as electrical conductivity measurements.

Evaluation of disease activity in systemic lupus erythematosus using standard deviation of lymphocyte volume combined with red blood cell count and lymphocyte percentage

Systemic lupus erythematosus (SLE) commonly damages the blood system and often manifests as blood cell abnormalities. The performance of biomarkers for predicting SLE activity still requires further improvement. This study aimed to analyze blood cell parameters to identify key indicators for a SLE activity prediction model. Clinical data of 138 patients with SLE (high activity, n = 40; moderate activity, n = 44; mild activity, n = 37; low activity, n = 17) and 100 healthy controls (HCs) were retrospectively analyzed. Data from 89 paired admission–discharge patients with SLE were collected. Differences and associations between blood cell parameters and disease indicators, as well as the relationship between the these parameters and organ damage, were examined. Machine-learning methods were employed to develop a prediction model for disease activity evaluation. Most blood cell parameters (22/26, 84.62%) differed significantly between patients with SLE and HCs. Analysis of 89 paired patients with SLE revealed significant changes in most blood cell parameters at discharge. The standard deviation of lymphocyte volume (SD-V-LY), red blood cell (RBC) count, lymphocyte percentage (LY%), hemoglobin(HGB), hematocrit(HCT), and neutrophil percentage(NE%) correlated with disease activity. By employing machine learning, an optimal model was established to predict active SLE using SD-V-LY, RBC count, and LY% (area under the curve [AUC] = 0.908, sensitivity = 0.811). External validation indicated impressive performance (AUC = 0.940, sensitivity = 0.833). Correlation analysis revealed that SD-V-LY was positively correlated with ESR, IgG, IgA, and IgM but was negatively correlated with C3 and C4. The RBC count was linked to renal and hematopoietic system impairments, whereas LY% was associated with joint/muscle involvement. In conclusion, SD-V-LY is associated with SLE disease activity. SD-V-LY combined with RBC count and LY% contributes to a prediction model, which can be utilized as an effective tool for assessing SLE activity.

Corneal Endothelial Cell Loss During Uneventful Cataract Surgery in Hispanics Versus Non-Hispanics.

Limited information exists on the possible effects of ethnicity on corneal endothelial cell parameters and their changes during cataract surgery. Thus, we evaluated corneal endothelial cell density (ECD) and endothelial cell loss (ECL) during surgery for senile cataract in Hispanic and non-Hispanic White adults. This retrospective study included 312 eyes of 227 patients ≥50 years who underwent phacoemulsification with intraocular lens implantation for senile cataract. Preoperatively and 1 to 2 months after surgery, specular microscopy was performed to measure ECD, coefficient of variation (CV), and hexagonal cell percentage (HEX). Regression analysis was used to compare baseline values as well as surgery-related changes in corneal endothelial cell parameters between Hispanic and non-Hispanic patients considering demographics, biometric parameters, and intraoperative cumulative dissipated energy (CDE). There were 109 Hispanics and 118 non-Hispanics. Anterior chamber depth (ACD) was significantly lower in Hispanics (3.12±0.36 mm) compared with non-Hispanics (3.25±0.37 mm, P=0.009). There were no significant differences in baseline ECD between Hispanics (2,547±365 cells/mm2) and non-Hispanics (2,483±380 cells/mm2, P=0.17). There were also no significant differences in ECL (16.8%±17.0% vs. 17.4%±18.1%, P=0.46), increase in CV (3.8%±20.7% vs. 1.5%±21.6%, P=0.51), and decrease in HEX (-2.7%±8.5% vs. -1.8%±7.0%, P=0.33) between these two groups. Regression analysis showed that ECL was associated with a shallower ACD (P=0.003), a higher CDE (P<0.001), but not with ethnicity (P=0.46). There are no significant differences in ECD and ECL between Hispanics and non-Hispanics undergoing cataract surgery. Although Hispanics have a shallower ACD, the ethnic difference seems to be clinically insignificant.

Studies on highly stable Na7Fe3(P2O7)4 as anode materials for lithium-ion batteries and migration behavior of lithium ions

In this paper, Na7Fe3(P2O7)4 target material is firstly evaluated as potential anode material for lithium ion batteries. It is found to have good electro-chemical performance and high stability as anode material for lithium batteries. It shows a capacity of 290 mAh g−1 for 200 cycles and increases to 388 mAh g−1 for 1000 cycles at a current density of 150 mA g−1. The Coulomb efficiency is maintained at about 98 % during the long cycling. The ex-situ experimental results indicate that Na7Fe3(P2O7)4 has high structural stability and the changes of cell volume and cell parameters are <0.62 % during charging and discharging. The results of GITT data show that the diffusion coefficients range from 3.15 × 10−11 cm2 S−1 to 1.12 × 10−12 cm2 S−1.The Li+/Na+ diffusion paths are estimated by the Bond valence-energy landscape (BEL) method and the exact energy barriers and minimal energy paths (MEPs) are determined using the nudged elastic band (NEB) method implemented in density functional theories (DFT). A two dimensional Na+ diffusion network is observed and Na+ diffusion along c-axis is prohibited. For the initial discharge stage, Na+ migrates in the Na+ transportation channel with an energy barrier of 0.48 eV along a-axis and 0.46 eV along b-axis. For the discharge later on, the intercalated Li+ enters the nearby Na+ vacancies and also migrate in the Na+ channel except Li+ at 8f Lid sites, which will stay where it is firstly introduced because of the higher energy barrier of 0.75 eV. The immobility of Lid is one of the important reasons for the irreversible capacity loss after the initial charge/discharge cycle.

Characterization of rear-side potential-induced degradation in bifacial p-PERC solar modules

Bifacial solar modules are increasingly preferred over monofacial modules to maximize the solar power output within a limited space. Owing to their high efficiency and compatibility with existing production lines, bifacial p-type passivated emitter and rear contact (p-PERC) solar modules have dominated the market since their commercialization. This study analyzes the influence of Al2O3, a passivation layer of p-PERC solar cells, on the PID and its underlying mechanism. Experiments were conducted on bifacial p-PERC module samples to analyze their electrical properties. Additionally, cell-like samples were fabricated to measure characteristics, for example, carrier lifetime, that are difficult to assess in full modules. To accelerate module degradation, experiments were conducted at 85 °C and 85 % humidity, while a voltage of −1000 V was applied to investigate the PID phenomenon. The results reveal degradation at the rear of the module caused by polarization effects, which were confirmed through changes in solar cell parameters and recombination current. The proposed mechanism indicates that the degradation in bifacial p-PERC solar modules is caused by the field-effect deterioration of the Al₂O₃ layer caused by alkali ions diffusing from the glass. This is observed through changes in the carrier concentration within Si and the detection of alkali ions within Al2O3. Our analysis considers both module and cell structure samples to delineate the influence of Al2O3 on the PID, which has not been previously reported. This study enhances the understanding of the polarization effect in bifacial p-PERC solar cells, thus contributing to the advancement of solar cell passivation strategies.

Investigating Cathode Dynamics in Realistic Desalination Reactors Using Operando High-Energy Synchrotron X-Ray Microscopy

Four billion people suffer from lack of clean water at least one month of the year.[1] This critical water shortage applies not only to the supply of potable water, but also to water for use in industrial, agricultural, and energy applications. While water resources like seawater are abundant, hardly any water resource is clean enough for direct use. Desalination provides a methodology to render unusable waters from such water resources fit for use. An innovative and particularly energy-efficient electrochemistry-based approach is the Desalination Battery (DB), which stores the energy input during desalination in chemical bonds between ions and faradaic electrode, allowing for its recovery during the salination process. DBs are at the forefront of the water-energy nexus[2]. While they are promising for seawater desalination (e.g., for seawater to brackish water conversion), practical implementation and their full potential still need to be unlocked. To this end, foundational understanding of the atomic- to electrode-scale physics/chemistry underlying functionality and degradation must be unraveled.Towards this end, we utilized our unique flow-by reactor setup to combine electrochemistry, conductivity, and temperature measurements with high-energy (75 keV) operando synchrotron X-ray diffraction (HEXRD) microscopy. Our investigation encompasses both the atomic and electrode levels, using a 3-electrodes setup with LiMn2O4 and Na0.44MnO2 as electrode active materials. As such, we were able to simulate a realistic electrode environment for operando measurements, as well as observe spatially resolved structural changes by scanning the beam across the electrodes surface. These phenomena are manifested through changes in unit cell parameters and the emergence of new phases during desalination cycles. Specifically, we tracked the changes in XRD patterns over the course of several desalination cycles in LiCl and NaCl solutions, as well as synthetic seawater and mixed solutions of LiCl/MgCl2. We were able to observe high selectivity of LiMn2O4 towards Li+, even in the highly concentrated synthetic seawater solutions, and could not observe the emergence of a new Mg+ rich phase down to potentials of 0 V vs. AgCl. Na0.44MnO2 exhibited good cycling behavior in synthetic seawater akin to pure NaCl solutions, and apart from the Na+ rich phase showed no signs of additional new phases, suggesting a highly selective nature towards Na+. Furthermore, we compared constant current and constant potential protocols and observed distinct differences in peak shift behavior. Ongoing analysis of the unit cell parameters and atomic positions allows us to allocate specific intercalation sites to specific potentials, providing foundational insight into the chemistry and physics underlying the selectivity of these materials.Literature:[1] M. M. Mekonnen, et al., Sci Adv 2016, 2, e1500323.[2] Q. Li, et al., Adv Sci (Weinh) 2020, 7, 2002213.

Change in Tacrolimus Concentration Measured in Whole Blood Correlates With Changes in Red Blood Cell Parameters After Red Blood Cell Transfusion in Kidney Transplant Recipients

BackgroundTacrolimus (TAC) is a narrow therapeutic range drug that requires therapeutic drug monitoring. TAC concentration is measured using whole blood owing to its high red blood cell (RBC) transfer rate of 95%. The distribution and whole-blood TAC concentration may be affected by the transfusion of red cell concentrates (RCCs); however, this has not been studied in kidney transplant recipients (KTR). Therefore, we investigated the relationship between changes in whole-blood TAC concentration and RBC parameters before and after RCC transfusion in KTR. MethodsFifteen KTR who received TAC and RCC transfusions were enrolled. The change rates of RBC parameters (RBC count, hemoglobin [Hgb], hematocrit [Hct]), and TAC concentration/dose before and after transfusion were calculated. The correlation between each RBC parameter and the TAC rate was evaluated. ResultsThe TAC concentration and rate increased after RCC transfusion. Moreover, the TAC rate showed a significant and strong correlation with RBC count, Hgb, and Hct, with RBC count showing the highest correlation coefficient (r = 0.811, 0.766, and 0.764, respectively; p < .01). Serum creatinine and potassium levels remained stable, suggesting the absence of typical adverse effects associated with TAC, such as acute kidney injury or hyperkalemia. ConclusionChanges in whole-blood TAC concentration and RBC parameters were correlated, and whole-blood TAC concentration increased after RCC transfusion. Therefore, the TAC dose should be adjusted accordingly.

High Capacity and Fast Kinetics Enabled by Metal-Doping in Prussian Blue Analogue Cathodes for Sodium-Ion Batteries.

Prussian blue analogues (PBAs) have gained tremendous attention as promising low-cost electrochemically-tunable electrode materials, which can accommodate large Na+ ions with attractive specific capacity and charge-discharge kinetics. However, poor cycling stability caused by lattice strain and volume change remains to be improved. Herein, metal-doping strategy has been demonstrated in FeNiHCF, Na1.40Fe0.90Ni0.10[Fe(CN)6]0.85 ⋅ 1.3H2O, delivering a capacity as high as 148 mAh g-1 at 10 mA g-1. At an exceptionally high rate of 25.6 A g-1, a reversible capacity of ~55 mAh g-1 still can be obtained with a very small capacity decay rate of 0.02 % per cycle for 1000 cycles, considered one of the best among all metal-doped PBAs. This exhibits the stabilizing effect of Ni doping which enhances structural stability and long-term cyclability. In situ synchrotron X-ray diffraction reveals an extremely small (~1 %) change in unit cell parameters. The Ni substitution is found to increase the electronic conductivity and redox activity, especially at the low-spin (LS) Fe center due to inductive effect. This larger capacity contribution from LS Fe2+C6/Fe3+C6 redox couple is responsible for stable high-rate capability of FeNiHCF. The insight gained in this work may pave the way for the design of other high-performance electrode materials for sustainable sodium-ion batteries.

Breathing Behavior and Superprotonic Conductivity of Two-Dimensional Flexible Metal-Organic Frameworks Tuned with Alkoxy Groups.

Flexible metal-organic frameworks (FMOFs) exhibit reversible structural transitions ("breathing" behaviors), which can regulate the proton transport passageway effectively. This property offers remarkable advantages for improving the proton conductivity. Our objective of this work is to design a single-variable flexibility synergistic strategy for the fabrication of FMOFs with high conductivity. Herein, four two-dimensional FMOFs, {[Co(4-bpdb)(R-ip)]·xsolvents}n (x = rich, 1-4), have been successfully designed and assembled (4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and R-ip = MeO/EtO/n-PrO/n-BuO-isophthalate). Upon the release and/or absorption of different solvent molecules, they display reversible breathing behaviors, thereby resulting in the formation of the partial and complete solvent-free compounds {[Co(4-bpdb)(R-ip)]·ysolvents}n (y = free or poor, 1A-4A). This breathing behavior involves the synergistic self-adaption of the dynamic torsion of alkoxy groups and reversible structural transformation, leading to remarkable changes in cell parameters and void space, as evidenced by single-crystal X-ray diffraction, powder X-ray diffraction, and N2 and CO2 adsorption analyses. At 363 K and 98% relative humidity, 2A exhibits the best proton conductivity among the FMOFs. Its conductivity reaches 4.08 × 10-2 S cm-1 and is one of the highest conductivities shown by reported unmodified MOF-based proton conductors.

Diagnostic value of whole blood cell parameters logistic regression model for radiation injury on radiation workers

Objective: To explore the diagnostic value of whole blood cell parameters logistic regression model for radiation injury on radiation workers by comparing the differences of whole blood cell parameters between occupational radiation injury population and occupational health examination population. Methods: In February 2023, 184 radiation workers who received occupational health examinations in our hospital and occurrenced chromosome aberration from July 2021 to July 2022 were retrospectively selected as the radiation injury group. And other 184 radiation workers encountered in the same period without chromosome aberration occurrence were selected as the control group. Collected whole blood cell parameters from two groups of research subjects, conducted comparative analysis, constructed a logistic regression model, and evaluated the diagnostic value of the logistic regression model for radiation injury on radiation workers by receiver operating characteristic curve (ROC) and area under curve (AUC) . In addition, with the same standard, 60 radiation workers with chromosome aberration and 60 radiation workers without chromosome aberration from August 2022 to January 2023 were included in the validation queue to validate the logistic regression model. Results: Neu_X, Neu_Y, Neu_Z, Lym_X, Lym_Y, Lym_Z, Mon_X, Mon_Y, Mon_Z, Micro, MCHC in the radiation injury group were significantly higher than those in the control group, and the difference was statistically significant (P<0.05) . And MCV and Macro in the radiation injury group were lower than those in the control group, and the difference was statistically significant (P<0.05) . Moreover, logistic regression analysis showed that Lym_X, Lym_Y, Lym_Z, MCHC, Micro were all independent risk factors for diagnosing radiation injury on radiation workers (OR=1.08、1.02、0.99、1.06、51.32, P<0.05) . ROC curve analysis showed that the AUC, sensitivity, specificity, and accuracy of the logistic regression model based by Lym_X, Lym_Y, Lym_Z, MCHC and Micro in diagnosing radiation injury on radiation workers were 0.80, 85.9%, 65.8% and 75.9% respectively. The validation queue verified the logistic regression model and the AUC, sensitivity, specificity, and accuracy of the logistic regression model were 0.80, 81.7%, 71.7% and 76.7% respectively, the model fitted well. Conclusion: Radiation damage can cause changes in multiple whole blood cell parameters of radiation workers. The logistic regression model based by Lym_X, Lym_Y, Lym_Z, MCHC and Micro showed good diagnosis ability and can be used for the screening of radiation injury on radiation workers.

Pathogenesis and therapy of anemia in patients with inflammatory bowel diseases

Background. Anemia represents one of the most frequent complications in inflammatory bowel disease and severely impairs the quality of life of affected patients. The etiology of anemia in inflammatory bowel disease patients can be multifactorial, often involving a combination of iron deficiency anemia and anemia of chronic disease. The choice of therapy, focused on the leading cause of anemia, allows for individualized therapy, minimizing the risk of side effects and the cost of therapy.Aim. A comparative analysis of blood parameters before and after treatment was performed.Materials and methods. For 5 years, 47 patients (15 women, 32 men) with inflammatory bowel disease with a median age of 48 years (from 28 to 65 years) were studied. Two groups were formed: patients with iron deficiency anemia and patients with anemia of chronic disease. Patients with combination of iron deficiency anemia and anemia of chronic disease D (n = 21) were not included. A division was also made according to the type of treatment performed.Results. In the iron deficiency anemia group, a statistically significant increase in hemoglobin level was revealed as a result of the use of intravenous iron. During therapy with oral iron and B vitamin therapy, as well as therapy aimed only at correcting gastrointestinal tract pathology, no reliable dynamics of the studied parameters was observed. In the anemia of chronic disease group, there were no significant changes in red blood cell parameters with any of the treatment options (p &gt;0.05).Conclusion. The effectiveness of various therapeutic approaches to correct anemia is controversial. Further follow-up and an increase in the sample size are needed, which will help individualize therapy and improve the patients’ quality of life.

Changes in red blood cell parameters during incremental exercise in highly trained athletes of different sport specializations.

During physical exercise, the level of hematological parameters change depending on the intensity and duration of exercise and the individual's physical fitness. Research results, based on samples taken before and after exercise, suggest that hematological parameters increase during incremental exercise. However, there is no data confirming this beyond any doubt. This study examined how red blood cell (RBC) parameters change during the same standard physical exertion in athletes representing different physiological training profiles determined by sport discipline. The study included 39 highly trained male members of national teams: 13 futsal players, 12 sprinters, and 14 triathletes. We used multiple blood sampling to determine RBC, hemoglobin (Hb), hematocrit value (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red blood cell distribution width (RDW) before, during (every 3 min), and after (5, 10, 15, 20, and 30 min) an incremental treadmill exercise test until exhaustion. There were no significant exercise-induced differences in RBC parameters between athletic groups. No significant changes were recorded in RBC parameters during the low-intensity phase of exercise. RBC, Hb, and Hct increased significantly during incremental physical exercise, and rapidly returned to resting values upon test termination. The general pattern of exercise-induced changes in RBC parameters is universal regardless of the athlete's physiological profile. The changes in RBC parameters are proportional to the intensity of exercise during the progressive test. The increase in hemoglobin concentration associated with the intensity of exercise is most likely an adaptation to the greater demand of tissues, mainly skeletal muscles, for oxygen.

Study on the Stability of Hydrogen-Bonded Energetic Material 3-Nitropyrazole under High Pressure

The stability of hydrogen-bonded energetic material 3-nitropyrazole (3-NP, C3H3N3O2) under high pressure was studied using a diamond anvil cell, Raman spectrometer, and simulation calculation. Under the hydrostatic experimental pressure and simulated pressure of 10 GPa, the optical Raman spectra, the change of cell parameters, and the Hirshfeld surface energy of 3-NP were obtained respectively. The analysis of the measured Raman spectra shows that the structure is still in original phase at 10 GPa pressure. The effects of pressure on cell parameters, molecular arrangement, and hydrogen bonding were observed by simulation calculation. Systematic analysis of the subtle structural changes, anisotropic characteristics, and various interactions of 3-NP shows that the stability of 3-NP is related to the special trimer structure.

RF magnetron sputtering of [formula omitted] thin films: Analysis of thermal annealing induced tuning of structural, optical characteristics, and energy band alignments

This correspondence showcases the deposition of ultra-wide bandgap β−Ga2O3 thin films via the utilization of RF magnetron sputtering at an elevated deposition temperature of 400 °C, followed by a comprehensive analysis of their structural, surface and optical properties using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Raman, Ultraviolet–Visible Spectroscopy (UV–Vis), and Atomic Force Microscopy (AFM) at 800 °C, 900 °C, and 1000 °C annealed sample. Annealing up to 1000 °C led to a significant enhancement in the film’s crystallinity by 10%, accompanied by a remarkable decrease in dislocation density of up to 93.5%. The study also observed several key trends upon annealing, including a decreasing lattice constant from 12 to 11.97 Å, and an increase in the bandgap from 4.8 to 5.3 eV. Concurrently, crystallite size was consistently increased from 4.07 to 15.77 nm. The conduction band offset (CBO) decreased with higher annealing temperatures. Additionally, the increase in bandgap led to an enhancement in the critical electric field from 8.9 to 11.2 MV/cm. The Electron Density Mapping (EDM) results depicted a covalent bond between the atoms for different annealing processes along with the fundamental structural change in atomic coordinates and unit cell parameters, which has not been reported yet. These findings underline the remarkable material properties of β−Ga2O3 at 1000 °C temperatures. This establishes it as a compelling substitute for materials like SiC and GaN, showcasing its potential across various high-power applications due to a superior Baliga figure of merit and robust sensitivity even under elevated temperatures, positioning it as a promising candidate for optoelectronic applications.

Temporal Changes in CSF Cell Parameters After SAH: Comparison of Ventricular and Spinal Drain Samples

BackgroundForty percent of patients with aneurysmatic subarachnoid hemorrhage (aSAH) develop acute hydrocephalus requiring treatment with cerebrospinal fluid (CSF) drainage. CSF cell parameters are used in the diagnosis of nosocomial infections but also reflect sterile inflammation after aSAH. We aimed to study the temporal changes in CSF parameters and compare external ventricular drain (EVD)–derived and lumbar spinal drain–derived samples.MethodsWe retrospectively identified consecutive patients with aSAH treated at our neurointensive care unit between January 2014 and May 2019. We mapped the temporal changes in CSF leucocyte count, erythrocyte count, cell ratio, and cell index during the first 19 days after aSAH separately for EVD-derived and spinal drain–derived samples. We compared the sample sources using a linear mixed model, controlling for repeated sampling.ResultsWe included 1360 CSF samples from 197 patients in the analyses. In EVD-derived samples, the CSF leucocyte count peaked at days 4–5 after aSAH, reaching a median of 225 × 106 (interquartile range [IQR] 64–618 × 106). The cell ratio and index peaked at 8–9 days (0.90% [IQR 0.35–1.98%] and 2.71 [IQR 1.25–6.73], respectively). In spinal drain–derived samples, the leucocyte count peaked at days 6–7, reaching a median of 238 × 106 (IQR 60–396 × 106). The cell ratio and index peaked at 14–15 days (4.12% [IQR 0.63–10.61%]) and 12–13 days after aSAH (8.84 [IQR 3.73–18.84]), respectively. Compared to EVD-derived samples, the leucocyte count was significantly higher in spinal drain–derived samples at days 6–17, and the cell ratio as well as the cell index was significantly higher in spinal drain–derived samples compared to EVD samples at days 10–15.ConclusionsCSF cell parameters undergo dynamic temporal changes after aSAH. CSF samples from different CSF compartments are not comparable.

Controlling a Flotation Cell at the Peak Air Recovery Point

Air recovery is the fraction of air that leaves the pulp phase of a flotation cell and reports to the concentrate. There is a peak in this quantity as cell parameters change, and experimental and test work suggests that this peak is associated with maximum recovery of valuable material. If this is the case, then a control system that can operate the cell at the peak air recovery (PAR) point will be of great value. Previous attempts at achieving this objective have used extremum-seeking control methods. In this paper, a simpler and faster method based on a model of the rate of change of the air recovery is proposed. It is shown that the method maintains the cell at PAR when disturbances to the systems are imposed.

A deep learning-based transformer model for photovoltaic fault forecasting and classification

According to the US-based National Renewable Energy Lab (NREL), solar energy losses due to faults were 3.5 % in 2004, which increased to 17.5 % in 2018. Therefore, the fault prediction mechanism will enable PV practitioners to reduce losses effectively, enhancing the solar system's efficiency and power output. This paper proposes a deep learning-based Transformer model for robust fault prediction in photovoltaic. Transformer uses attention mechanism that considers data points as a language units “word” and learn dependencies among them to predict upcoming data points. Unlike other forecasting algorithms, our proposed approach does not rely on previous trends. In case of PV faults, trends do not exist. The proposed algorithm utilizes rate of change of solar cell parameters for establishing a trend to forecast faults, enabling proactive fault mitigation. It also classifies faults with different severity levels to identify the level of predictive maintenance required. The proposed approach is extensively evaluated using MATLAB on datasets of several faults with low, medium, and high severity levels. The proposed Transformer model achieves a forecasting mean average error (MAE) of 0.09377. Performance of the proposed forecasting and classification algorithm is compared with existing machine learning-based regression and classification techniques such as KNN, SVM, and NN, where proposed approach outperforms state-of-the-art approaches.

Haematological parameters and their correlation with the degree of malaria parasitaemia among outpatients attending a polyclinic

BackgroundMalaria is a parasitic disease caused by various species of the blood parasite Plasmodium; of all the parasitic diseases, malaria has the highest prevalence and mortality with an estimated 247 million cases and 619,000 deaths recorded worldwide as of 2021. Malaria causes febrile illness with several changes in blood cell parameters. Some of these changes include leucopenia, thrombocytopenia, and anaemia. If these changes could be correlated with the degree of parasitaemia, it can serve as a guide to physicians when treating malaria. This study was therefore aimed at correlating haematological parameters with levels of parasitaemia during malaria infection.MethodsThe study was a cross-sectional study involving 89 malaria positive patients. About 5 ml of blood was collected from each participant who gave his or her informed consent to partake in the study. A full blood count was performed on their samples to determine their haematological parameters using a haematology auto-analyzer. A parasite count was also performed via microscopy to determine the degree of parasitaemia. The data obtained from the study was entered into a database and statistically analysed using Statistical Package for Social Sciences (SPSS) version 23 and Microsoft Excel 2016.ResultsThe study comprised of 89 participants out of which 35 were males and 54 were females with the mean age of 26.15 years. Secondary education participants were the highest with quaternary education the lowest. The highest parasite count recorded was 398,174 parasites/µl of blood, lowest count was 101 with the average being 32,942.32584. There was also a significant positive Pearson’s correlation between total WBC and parasitaemia and with the WBC differentials, neutrophils, lymphocytes and monocytes had positive correlations while eosinophils and basophils had negative correlations. Furthermore, platelets, total RBC’s, haemoglobin, MCH, MCHC and Hct all showed negative correlations. Linear regression also showed a linear relationship between parasite density and the various haematological parameters.ConclusionThe linear relationship (correlation) between WBC and MCH were the only significant ones at 95% and 99% confidence interval, respectively based on a two-tail t-test. Also, based on the regression analysis, the changes caused by WBC and PLT were the only significant changes at 95% confidence level in a two-tailed t-test.

The Influence of Polyvinyl Alcohol Porogen Addition on the Nanostructural Characteristics of Hydroxyapatite.

Hydroxyapatite (HA) is a porous material widely developed in various research fields because of its high biodegradability, biocompatibility, and low toxicity. In this research, HA was synthesized using a hydrothermal method with chicken eggshells as a calcium source and various concentrations of polyvinyl alcohol as a porogen (2.5%, 5.0%, and 7.5% by wt). The structure and morphology of HA were determined by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. HA was obtained with varying concentrations of polyvinyl alcohol (PVA) porogen according to Inorganic Crystal Structure Database (ICSD) standard. Based on analysis using a refinement method, changes in unit cell parameters (cell volume and lattice strain) of HA synthesized using PVA porogen compared to the standard, the chi square (χ2) and index of R values were relatively low, validating the acceptable of the data. In addition, HA [Ca10(PO4)6(OH)2] with hexagonal structure and the P63/m space group was successfully obtained. Morphological analysis of HA by SEM found that HA has a spherical shape, and the porosity of HA increases with increasing concentrations of polyvinyl alcohol. The highest porosity was obtained with an addition of 5.0 wt% of PVA porogen (HAP3), reaching 69.53%.

Impact of Age on the Characteristics of Corneal Nerves and Corneal Epithelial Cells in Healthy Adults.

The aim of this study was to investigate age-related changes in corneal nerves and corneal epithelial cell parameters and to establish age-adjusted reference values. A total of 7025 corneal nerve images and 4215 corneal epithelial images obtained using in vivo confocal microscopy from 281 eyes of 143 healthy participants were included. Seven corneal nerve parameters and 3 corneal epithelial cell parameters were quantified using 2 automatic analytic software and analyzed across 6 age groups ranging from 21 to 80 years. There was a declining trend in all 7 nerve parameters with advancing age. In particular, corneal nerve fiber length and corneal nerve fiber density demonstrated a significant decrease in subjects aged 65 years or older compared with subjects younger than 65 years (10.8 ± 2.6 mm/mm 2 vs. 9.9 ± 2.0 mm/mm 2 , P = 0.011 in corneal nerve fiber length; 15.8 ± 5.2 fibers/mm 2 vs. 14.4 ± 4.3 fibers/mm 2 , P = 0.046 in corneal nerve fiber density), whereas corneal nerve fractal dimension demonstrated a borderline significant decrease ( P = 0.057). Similarly, there was a general declining trend in all epithelial cell parameters with advancing age. Corneal epithelial cell circularity was significantly lower in subjects aged 65 years and older as compared to subjects younger than 65 years (0.722 ± 0.021 μm 2 vs. 0.714 ± 0.021 μm 2 ; P = 0.011). Advancing age results in reduced corneal nerve metrics and alteration of corneal cell morphology. Aging effects should be considered when evaluating patients with corneal neuropathy.