Absorbance Units Research Articles

Modeling and economic analysis of block absorber (RadFrac) performance with stage variations for post-combustion CO2 capture

This study presents a comprehensive modeling and economic evaluation of a Monoethanolamine (MEA)-based post-combustion carbon capture (PCC) absorber unit. The simulation provides detailed insights into the absorber's internal profiles, including temperature gradients and the percentage of CO2 captured, with a particular focus on the effects of varying the number of stages and absorber diameters. Validation against experimental data demonstrated close alignment between simulated and observed values, with an average Root Mean Square Deviation (RMSD) of 0.018 and 4.0129, respectively, confirming the reliability of the simulation in capturing the complex dynamics of the absorber.The economic analysis, conducted using the Aspen Process Economic Analyzer (APEA), simplified the complex relationship between absorber segmentation, capital and operational costs, and absorber diameter. The study revealed that increasing the absorber diameter and the number of stages leads to a significant rise in Total Capital Cost (TCC), Total Operating Cost (TOC), Equipment Cost, and Total Installed Cost (TIC), with the highest costs observed at a stage number of 90 and a diameter of 1.0 m. However, the analysis identified an optimal configuration at an absorber diameter of 0.45 m with either 10 or 20 stages. This setup effectively balances cost and CO2 capture efficiency, offering a more economical solution compared to configurations with larger diameters and higher stage numbers, which substantially increase expenses. The findings highlight the critical trade-offs between operational efficiency and capital expenditure, stressing on the crucial role of absorber diameter in determining the economic feasibility of the absorber block in PCC systems.

Hydrodynamic cavitation assisted pretreatment of sugarcane bagasse in the presence of yeast cell mass for the production of sugars and their use for biopigments production by Monascus ruber

Hydrodynamic cavitation-assisted pretreatment of sugarcane bagasse tested in the, with the addition of yeast extract. This pretreatment was investigated using a 22 central composite design experiment. A total of 11 experiments were performed. The pretreated biomass was then tested for enzymatic hydrolysis for the sugars production. Various enzymatic loadings (15–20 FPU/g biomass) and concentrations of yeast extract (0.25–1 g/L) were studied during the enzymatic hydrolysis. Optimization of yeast extract insertion was performed to simultaneously facilitate the infusion of cellulolytic enzymes into the pores of the pre-treated bagasse concomitantly inhibiting enzyme absorption caused by residual lignin. The optimized results revealed an 81 % glucan hydrolysis yield and a 78 % xylan hydrolysis yield after the enzymatic hydrolysis under optimized conditions (20 FPU/g and 1 g/L of yeast extract). The hydrolysate rich in sugars derived from carbohydrate polymers and nitrogen sources derived from hydrolysis of yeast cream was assessed for biopigments production by Monascus ruber. The hydrolysate used for M. ruber fermentation showed the production of pigments with 15 AU (absorbance units) for yellow, 15 AU for orange and 20 AU for red after 9 days of fermentation. These results proved the efficiency of using yeast cream as a potential blocking agent of lignin in turn increasing the sugars production and a nitrogen source for the M. ruber for biopigments production from sugarcane bagasse hydrolysate.

Maternal serum ischemia-modified albumin as an oxidative stress biomarker in preterm pre-labor rupture of membranes.

To evaluate the maternal serum ischemia-modified albumin (IMA) concentration as an oxidative stress biomarker in pregnancies complicated by preterm pre-labor rupture of membranes (PPROM) without maternal clinical infection and compare these results with healthy pregnancies. The present cohort study included 40 pregnancies complicated by PPROM and 49 similar gestational age healthy pregnancies in the third trimester of gestation. Maternal venous blood specimens were obtained at the day of first diagnosis. Maternal serum IMA level was assayed with an Albumin Cobalt Binding test. The subjects were followed up until delivery and perinatal outcomes were recorded. The maternal serum IMA concentrations were significantly higher in the study group (0.56 ± 0.05 absorbance units) as compared to controls (0.54 ± 0.03 absorbance units) (p = 0.020). The maternal serum IMA concentrations were not significantly correlated with the initial maternal white blood cell count (r: 0.118, p = 0.269) and C-reactive protein levels (r: 0.066, p = 0.541). The maternal serum IMA concentrations were negatively correlated with gestational age at delivery (r: -0.248, p = 0.019), birthweight (r: -0.247, p = 0.020) and Apgar scores (r: -0.200, p = 0.049; r: -0.245, p = 0.020). The threshold value of maternal serum IMA concentration above 0.55 absorbance units indicated the pregnancy complicated by PPROM by 57.5% sensitivity and 57.1% specificity (Area under curve 0.613, confidence interval 0.50-0.73). The current study supported for the first time that there is an association between increased maternal serum IMA levels and the development of PPROM in the third trimester of gestation without maternal clinical infection. Elevated maternal serum IMA levels may alert the obstetrician about poor ongoing perinatal outcomes in the early phase of PPROM before increased maternal C-reactive protein and white blood cell count.

Design Optimization of a Point Absorber and Hydraulic Power Take-Off Unit for Wave Energy Converter

Design Optimization of a Point Absorber and Hydraulic Power Take-Off Unit for Wave Energy Converter

Visual inspection versus spectrophotometry for xanthochromia detection in patients with sudden onset severe headache-A diagnostic accuracy study.

There is still disagreement about whether to routinely use spectrophotometry to detect xanthochromia in cerebrospinal fluid (CSF) or whether visual inspection is adequate. We aimed to evaluate the diagnostic accuracy of these methods in detecting an aneurysmal subarachnoid hemorrhage in patients with sudden onset severe headache. When a patient presents to the emergency department with a headache for which there is suspicion of a subarachnoid hemorrhage, the gold standard to rule this out is to perform a CSF analysis for xanthochromia with or without spectrophotometry if the cranial non-contrast computed tomography (CT) upon admission is negative. Having applied the gold standard, we retrospectively included patients with acute headache who underwent both CT scan and CSF spectrophotometry at our hospital in the period 2002-2020. Patients were excluded if the cranial CT was interpreted as positive, there was a bloody CSF, or if visual assessment data of the CSF was unavailable. We scrutinized the patients' medical records and evaluated the benefit of spectrophotometry compared to visual inspection. The net bilirubin absorbance cut-off for support of subarachnoid hemorrhage was set at >0.007 absorbance units. The spectrophotometry was also considered positive if the net bilirubin absorbance was ≤0.007 and net oxyhemoglobin absorbance was ≥0.1 absorbance units. We calculated and compared the sensitivity and specificity of CSF spectrophotometry and visual inspection of the CSF. In total, 769 patients, with a mean age of 42.3 ± (standard deviation [SD] = 17.3) years, were included. The headache onset was classified as a thunderclap headache in 41.5%, and 4.7% had a sudden loss of consciousness. Fifteen patients (2%) were finally diagnosed with a subarachnoid hemorrhage, six (0.8%) had an aneurysmal subarachnoid hemorrhage, seven (0.9%) had a perimesencephalic hemorrhage, one (0.1%) had a cortical cerebral sinus venous thrombosis, and one (0.1%) had a spinal epidural hematoma. Four patients (0.5%) had a subarachnoid hemorrhage that was not detected by visual inspection, and two were caused by an aneurysmal rupture. One of these two patients died just before intervention, and the other underwent coiling for an anterior communicating aneurysm. The number needed for lumbar puncture to detect a subarachnoid hemorrhage was 51, but 128 to detect an aneurysmal hemorrhage. The corresponding numbers needed for CSF spectrophotometric analysis were 192 and 385, respectively. Spectrophotometry was positive in 31 patients (4.0%), of whom 18 (2.3%) also had visually detected xanthochromia (11 true positive). The mean net bilirubin absorbance in the 13 samples with visually clear CSF was 0.0111 ± (SD = 0.0103) absorbance units, compared to 0.0017 ± (SD = 0.0013) in the CSF with negative spectrophotometry. The corresponding figures for net oxyhemoglobin absorbance were 0.0391 ± (SD = 0.0522) versus 0.0057 ± (SD = 0.0081). The sensitivity of spectrophotometric xanthochromia detection was 100% (95% confidence interval [CI], 78-100), compared to 73% (95% CI, 45-92) for visual xanthochromia detection. The specificity of spectrophotometric xanthochromia detection was 98% (95% CI, 97-99) compared to 99% (95% CI, 98-100) for visual xanthochromia detection. Both methods had high negative predictive values: 100% (95% CI, 99.5-100) versus 99.5% (95% CI, 98.6-99.9), respectively. Both visual inspection and spectrophotometry have high diagnostic accuracy for detecting CSF xanthochromia, but the lower sensitivity of visual assessment makes it unreliable, and we recommend the use of spectrophotometry in clinical practice.

All-dielectric ultra-broadband transparent imidazole ionic liquid-based metamaterial absorber with a frustum-shaped structure

In this study, a frustum-shaped addition was made to a cylindrical absorber unit, utilizing 1-ethyl-3-methylimidazolium dicyanamide ionic liquid (IL) to create a transparent all-dielectric liquid metamaterial absorber (A-D ILMMA). The A-D ILMMA achieved over 90% absorption efficiency across 4.86–50.00 GHz, with a 165% relative absorption bandwidth. It maintained robust performance across various polarization angles and achieved over 77% absorption at incident angles of up to 60°. Owing to the excellent thermal stability of the IL, the A-D ILMMA consistently maintained an absorption rate of over 90% across a temperature range from 25 °C to 100 °C. The high absorption rates were attributed to synergistic impedance matching and electromagnetic energy loss. The experimental results confirmed over 90% absorption in the ultra-broadband range of 7.10 GHz to 40.00 GHz, demonstrating the excellent physicochemical properties of ILs and their potential applications.

Synthesis and characterization of flexible CaCoAlFe2O4 based microwave substrate for triband polarization-insensitive metamaterial absorber

This study investigated CaxCo(0.90-x)Al.01Fe2O4 nanoparticle synthesized using the sol–gel synthesis method to achieve a flexible substrate with a high dielectric constant value. The XRD, FESEM, and dielectric characteristic is analyzed to explore the performance of the suggested Ox Wheels-shaped (OWS) metamaterial absorber unit cell. The X-ray diffraction (XRD) analysis found significant peaks at 30° (318), 33° (176), 35° (794), 43° (232), 53° (116), 57° (256), 62° (304), and 74° (126) planes. The dielectric constant values of the prepared nanomaterial materials are 4.52 (X = 90 %), 4.73 (X = 60 %), and 5.07 (X = 30 %) due to the deviations in raw material compositions. The prepared, flexible substrate is used in the anticipated OWS metamaterial absorber unit cell, and analysis has been widely considered and continuously concerned due to their excellent ultra-thin thickness, lightweight, and high absorbance resonance features. The predicted structure reached S21 response at 3.47 GHz, 7.05 GHz, and 10.76 GHz with the magnitude of −24.11 dB, −17.07 dB, and −19.19 dB, respectively, using CST simulation software. The absorber prototype is measured for further investigation within the frequency range of 2.25–2.76, 5.84–6.15 GHz, and 9.63–9.76 GHz, where maximum magnitude is achieved at 2.50 GHz, 6.02 GHz, and 9.70 GHz, respectively. This specific resonance frequency reached the highest 99.61 %, 98.03 %, and 98.79 % absorption, which covers the S, C, and X band frequency spectrum. Various electrical, magnetic, mechanical, and multi-parameter responses are examined to achieve almost perfect absorption (PA). The enormous range of possible uses of metamaterial, such as absorber wave modification, infrared imaging, radiative cooling, energy harvesting, and chemical detection, makes it appreciated. The CaCoAlFe2O4 ferrite-based flexible metamaterial absorber structure has ultra-thin, flexible, and non-corrosive advantages.

Evaluation of the correlation of serological and intradermal allergen testing with clinical history in 29 dogs with atopic dermatitis.

Limited information exists about the correlation between clinical history and positive serum (SAT) and intradermal allergen test (IDAT) results in atopic dogs. To evaluate the correlation between clinical history and SAT/IDAT results in atopic dogs. Twenty-nine client-owned dogs with nonseasonal atopic dermatitis with or without seasonal exacerbation were enrolled. IDAT, SAT (immunoglobulin (Ig)M antibody capture enzyme-linked immunosorbent assay [MacELISA] with bromelain CCD inhibitor) and clinical information collected in a questionnaire regarding seasonal variations in pruritus affecting the dogs were performed on the same day. Two independent investigators (Inv A and Inv B) recorded IDAT results. The kappa coefficients agreement for positive IDAT scores between Inv A and B was substantial. The agreement between IDAT and SAT results at different ELISA absorbance units (EAU) cut-offs (>79 and ≥300) was slight and fair for both investigators, respectively. A higher agreement was observed between IDAT and SAT (≥300 EAU) than between IDAT and SAT (>79 EAU) with the exception of mite and flea allergens. There was a statistically significant association between clinical history and positive IDAT results for seasonal allergens (Inv A and Inv B, p = 0.016). There was no significance between positive SAT results and clinical history. Five (IDAT) and 12 of 13 (SAT) atopic dogs without clinical seasonal exacerbation showed positive results for seasonal allergens. The agreement between IDAT and SAT ≥300 EAU results was fair and the agreement between IDAT and SAT >79 EAU results was slight for all allergens. Only positive IDAT results significantly correlated with clinical history.

Nano-structured metamaterial absorber based on a plus-shaped resonator for optical wavelength applications

Metamaterial absorbers have sparked widespread interest due to their remarkable electromagnetic properties, which enable a wide range of applications in light absorption and manipulation. This study introduces a new three-layer nanomaterial absorber (NMA) unit cell composed of nickel (Ni), silicon dioxide (SiO2), and nickel (Ni) designed to operate across the entire visible spectrum (390–780 nm). We demonstrate the NMA’s exceptional absorption characteristics through rigorous numerical simulations using industry-standard software, achieving a mean absorption rate of 97.17% and a maximum absorption peak of 99.99% at 694.89 nm under standard angles. Furthermore, the NMA unit cell has good impedance matching, efficient coupling between capacitors and inductors, and significant plasmonic resonance properties. Fabrication feasibility and potential applications in solar energy harvesting, optical sensing, and light detection.

Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH3/H20 absorption chiller

In recent years, the demand for cooling has seen a substantial increase, primarily due to rising summertime temperatures. Conventional mechanical compression air conditioners have played a predominant role in fulfilling this demand, albeit at the cost of significant electricity consumption. In response, absorption chillers have emerged as an eco-friendly alternative, powered by sustainable heat sources like solar energy or industrial waste heat. The present work is conducted within the framework of developing compact absorption chillers incorporating plate heat exchangers. It builds upon prior research by improving an existing numerical model for falling film plate heat exchangers within an NH3/H2O absorption chiller. This former numerical model evaluates the coupled heat and mass transfer between the liquid film and the vapor flow while excluding hydrodynamic interactions at the liquid-vapor interface. The current investigation aims to address compactness and cost-efficiency limitations in absorption chillers. The consequences of operation within confined spaces were numerically evaluated. An innovative analytical model was developed to quantify the influence of the interactions at the liquid-vapor interface. Shear stress and interfacial perturbations were considered compared to the classical Nusselt model, enabling the evaluation of the changes in the average film thickness and the flooding phenomenon. This analytical model was then added to the previously developed heat and mass transfer model. The numerical model was applied to both the desorber and absorber units. The results show that increased confinement has minimal effects on the transfer coefficients. Additionally, an approach is suggested for estimating flooding in confined spaces and the results are compared with various correlations available in the literature.

Performance of a Norfentanyl Immunoassay in Specimens with Low Concentrations of Fentanyl and/or Norfentanyl.

Many fentanyl immunoassays are limited in their ability to detect norfentanyl. Urine specimens collected from individuals who have been exposed to fentanyl frequently have detectable concentrations of norfentanyl (≥2 ng/mL) but low concentrations of fentanyl (<2 ng/mL) by LC-MS/MS. The Lin-Zhi Fentanyl II Immunoassay (Lin-Zhi) claims 100% cross-reactivity with norfentanyl and therefore may detect exposure missed by other assays. In addition to verifying the manufacturer's analytical sensitivity claims, we selected 92 urine specimens with low-positive Lin-Zhi results (1-99 absorbance units, lowest 10%) for analysis by the Immunalysis Health Equity Impact Assessment and ARK II fentanyl methods. The accuracy of the 3 immunoassays was compared to LC-MS/MS as the reference method. Spiking studies using purified fentanyl and norfentanyl and a set of 100 consecutive specimens confirmed the manufacturer's claims of limit of detection for fentanyl (3.8 ng/mL) and norfentanyl (5.0 ng/mL). However, the 92 low-positive patient specimens demonstrated concentrations of norfentanyl and fentanyl below 2.0 ng/mL by LC-MS/MS, with 47 (51%) having only norfentanyl detected. When comparing Lin-Zhi to the Immunalysis and ARK II immunoassays, only 27 (29%) of the 92 specimens were concordant. Fifty-two (57%) of the specimens were positive by LC-MS/MS and Lin-Zhi but false negative by one or both other immunoassays. Seven specimens (8%) were positive by Lin-Zhi but negative by the other immunoassays and had undetectable concentrations (<2 ng/mL) of fentanyl and norfentanyl by LC-MS/MS. The clinical sensitivity of the Lin-Zhi exceeds the manufacturer's claims, providing results comparable to LC-MS/MS methods.

Evaluating solvent efficiency for carbon capture: Comparative analysis of temperature, concentration and diffusivity effects

In the pursuit of efficient carbon capture technologies, the selection and design of solvents play a pivotal role, directly impacting various crucial factors such as CO2 absorption capacity, equipment size, and regeneration energy requirements. The primary focus is on optimizing solvent systems through a comprehensive analysis of intermolecular interaction intensity, diffusion coefficient, and intra-molecular interaction intensity. This study employs a molecular dynamics simulation model to identify the most suitable solvent system by assessing the effect of operating variables like temperature, concentration, interaction intensity, and diffusivity of various single and blended amine systems. The assessment utilizes the radial distribution function and mean square displacement analysis. The results indicate that intermolecular interactions with CO2 are most significant in 30 wt% 2EAE, 40 wt% 2DMAE and 10% DMCA with 20% MCA ratio concentrations. TMPAD, in particular, stands out for its high repulsive interaction and low energy requirement for breaking the carbamate/bicarbonate ion. Diffusion behavior in various observed solvent systems is as follows: EAE > MEA > DMAE > MAE-DEAB > MAE-DMA2P > EAE-TMPAD > AMP-PZ > EAE-DEAB > MAE-TMPAD > EAE-DMA2P > MAE-DMAE > EAE-DMAE > TMPAD > MEA-AMP > DMA2P > DMCA-MCA > DEAB > MEA-PZ. Moreover, elevated temperatures facilitate enhanced diffusivity, leading to accelerated mass transfer rates. This implies the possibility of reducing the size of absorber units and lowering energy consumption. Further studies on heat of absorption and kinetic characteristics of solvent blends are necessary to ensure their practical applicability in carbon capture and industrial operations.

Preparation of a double-layer bionic bamboo structure absorber based on CB/PLA-TPU composites and its broadband microwave absorption characteristics

The study of the mechanical characteristics and microwave absorption capabilities of multifunctional composite materials in complex environments has attracted considerable interest in recent years. Inspired by the structure of bamboo in nature, a novel double-layer microwave absorber structure, a CB/PLA-TPU composite bionic bamboo joint’s structure, was conceived and manufactured for this investigation. This structure ingeniously integrates the load-bearing attributes of bamboo joints with the microwave absorption qualities of CB composites. At the material level, enhancing the CB particle content enhances the matrix's folds and defects, thereby improving its dielectric polarization loss capacity. An effective absorption bandwidth of 3.84 GHz was achieved, with a minimum reflection loss of −60.24 dB at a 2.58 mm thickness and a 9.2 GHz frequency. The bionic bamboo absorber's unit structure is meticulously engineered, with experimental simulations validating its performance. According to the findings, the structure attains a 10.03 GHz broadband absorption and a yield strength of 11.6 MPa. It maintains broadband absorption capabilities above 9 GHz even at oblique incidence angles for TM polar wave (0–60°) and TE polar wave (0–30°). The biomimetic design based on bamboo offers significant potential for engineering applications in stealth technology under adverse conditions.

Evaluation of Salivary Butylated Hydroxytoluene and Ascorbic Acid Levels in Type 2 Diabetes Mellitus Patients.

Type 2 diabetes mellitus (T2DM) is a global health concern associated with systemic as well as oral complications. The preventive antioxidants found in saliva naturally reduce the damaging effects of reactive oxygen molecules. Any disruption to the regular functioning of these antioxidants may lead to oxidative stress, which could boost an individual's vulnerability to oral diseases. Diabetes patients are vulnerable to various dental complications, such as oral mucosal disorders, dental caries, dry mouth, and periodontal disease. This study aimed to assess the salivary butylated hydroxytoluene (BHT) and ascorbic acid (AA) levels in patients with controlled and uncontrolled type 2 diabetes mellitus. The present study included samples from patients aged 45-65. Group I consisted of 20 controlled diabetic patients, and Group II consisted of 20 uncontrolled diabetic patients. Unstimulated whole saliva samples were collected from both groups, and laboratory analysis was done. Salivary BHTand AAlevels were quantified using enzyme-linked immunosorbent assay (ELISA) and spectrophotometric assay. Salivary butylated hydroxytoluene levels were found to be higher in the uncontrolled diabetic group than in the controlled diabetic group, and salivary AA levels were found to be higher in the controlled diabetic group than in the uncontrolled diabetic group. The mean ± standard deviation (SD) values of butylated hydroxytoluene among controlled and uncontrolled diabetic patients were 2.98 ± 0.12 and 2.99 ± 0.11 absorbance units, respectively. The mean ± SD value of AA in the controlled group was found to be 2.99 ± 0.15 absorbance units, and the mean ± SD value of AA in the uncontrolled group was 2.64 ± 0.96 absorbance units. However, it has been found that there is no statistically significant difference between salivary BHT and AA levels among controlled and uncontrolled diabetics, with p-values of 0.867 and 0.419, respectively. Values of salivary biochemical markers were distinctly different between controlled and uncontrolled diabetic groups. However,to establish a definite role of salivary BHT and AA levels as biomarkers in managing and monitoring type 2 diabetes, future studies are required, even though the trends exhibit possible alterations in biomarkers.

S-band application: Ultra-slim metamaterial absorber unit cell with dual-negative characteristics and polarization neutrality

The current work offers an electromagnetic metamaterial absorber that uses the double-a1Qnegative property and is designed for operation in the 1 to 4 GHz frequency range, with a peak absorption at 3.31 GHz, emphasizing S-band applications. The suggested structure is very thin, having a total absorber thickness of 0.0184 λ. It was constructed using CST software and simulated with a frequency domain solver. The unit cell's performance is studied at different polarization angles (φ) and incidence angles (θ). The results show good design, insensitivity to polarization angles up to 90°, and a wide incidence angle range of up to 50°.The investigation comprises an analysis of the electric field (E field) and surface current to supplement the absorption analysis. The suggested design is developed by parameter studies, which include changes to the split gap, loss tangent, and testing alternative substrate materials and thicknesses. The resonance frequencies vary somewhat according to array arrangements, resulting in double-negative characteristics. The fractional bandwidth is 5.4 %, with a central frequency of 3.31 GHz. The suggested design is validated using advanced design system (ADS) software, and the comparable circuit is shown to correspond very well with the CST simulation findings. The absorber is constructed on a FR-4 substrate in a 10 x 10 array format. Comparative analysis with existing literature indicates acceptable results, highlighting the potential utility of this metamaterial absorber design in S-band applications.

Association between ischemia-modified albumin (IMA) and peripheral endothelial dysfunction in rheumatoid arthritis patients

The identification of circulating biomarkers of endothelial dysfunction (ED), a precursor to atherosclerosis, in rheumatoid arthritis (RA) would facilitate early risk stratification and prevention strategies. Ischemia-modified albumin (IMA) has emerged as a potential biomarker of oxidative stress, ischemia, and ED. However, studies examining the relationship between IMA and ED in RA patients are lacking. We measured serum IMA concentrations by using an albumin cobalt binding test and peripheral vasodilatory capacity by EndoPAT in 113 RA patients without previous cardiovascular events enrolled in the EDRA study (ClinicalTrials.gov: NCT02341066). The mean peripheral vasodilatory capacity, expressed by the log of reactive hyperemia index (logRHI), was 0.82, corresponding to 27% RA patients having ED. The mean plasma concentrations of IMA were 0.478 absorbance units. We observed a significant and inverse association between peripheral vasodilatory capacity and serum IMA concentrations (rho = − 0.22, p = 0.02). In univariate logistic regression, ED was significantly associated with serum IMA concentrations [OR 1173 (95% CI 1.3568 to 101,364), p = 0.040) and higher disease activity. In multivariate logistic regression, the independent association between ED and IMA remained significant after correction for disease activity and other RA-confounders [OR 2252 (95% CI 1.0596 to 4,787,505), p = 0.048 in Model 1; OR 7221 (95% CI 4.1539 to 12,552,859), p = 0.02 in Model 2]. Conclusions: This study suggests that IMA is a promising biomarker of ED in RA. Further research is needed to confirm our findings and determine the clinical utility of IMA in detecting and managing early atherosclerosis in RA patients.

Swastika-shaped rotationally symmetric quadruple-structured near-infrared metamaterial absorber for absorbing solar energy

In this work, silicon dioxide based four-fold swastika shaped metamaterial nano structure absorber for solar radiation absorption in the near infrared (NIR) regime is proposed. The dimension of the unit cell is 648.50 × 648.50 nm2 which is designed on dielectric silicon dioxide and metallic conductor aluminum. The proposed structure is investigated by the finite-deference time domain (FDTD) method based software CST microwave studio. The metamaterial absorber (MMA) unit cell is simulated within the frequency range (200–398) THz that yielded dual resonance peaks at 260 THz and 378.0 THz with 95.50 % and 97.32 % of absorbance of solar energy, respectively. Additionally, the proposed nano design structure of unit cell was boosted up to attain the dual absorption band by engineering the design parameters. The electromagnetic response of the MMA was theoretically inspected and the excellent properties of the proposed designed absorber have promising applications in plasma-enhanced photovoltaic, optical absorption switching and infrared modulator optical communication.

Dual-Band Metamaterial Microwave Absorber using Ring and Circular Patch with Slits

This paper proposes a dual-band metamaterial microwave absorber operating at 2.5 GHz and 5.8 GHz. The absorber consists of a ring and a circular patch with slits resonator structures printed on a FR4 dielectric substrate backed by a ground layer. The main advantage of the absorber lies in its design flexibility in which each absorption band is independent and can be individually tuned by changing the dimensions of each resonator structure. The absorber unit cell is simulated and parametrically optimized using Computer Simulation Technology (CST) software. The absorption mechanism is analyzed through surface current analysis. The absorber prototype, with dimensions of 200 × 200 × 1.6 mm3 and consisting of an array of 7 × 7 unit cells, is fabricated and experimentally investigated using antennas in free-space measurement. The absorber exhibits over 97% absorption at both resonance frequencies. Furthermore, the absorber is demonstrated to be applicable in sensing applications for dielectric constant determination. With its design simplicity, wide-angle receptive, and polarization insensitive behavior, it is envisaged that the proposed absorber will find practical use in absorbing and sensing applications.

Recovery of polyphenols from corn cob (Zea mays L.): Optimization of different green extraction methods and efficiency comparison

The present work focuses on the recovery of polyphenols from Lombard corn cob to develop a new upcycled ingredient. Three different green extraction methods were evaluated using an experimental design approach: a conventional extraction (CSE-HA) and a microwave-assisted extraction (MAE-HA) using hydroalcoholic solvents, and a more innovative MAE method using natural eutectic solvents (MAE-NaDES). From mathematical modelling, three optimized extracts were obtained: CBE-1 from CSE-HA (50.3 % of ethanol, 60 °C, 89.9 min, and 32.7 mL/g solvent solid ratio - SSR), CBE-2 from MAE-HA (62.4 % ethanol, 88 °C, 5 min, and 42.8 mL/g SSR), and CBE-3 from MAE-NaDES (20 % water content, 90 °C, 5 min, and 20 mL/g SSR). The highest polyphenolic yield, reported as total metabolites content (TMC), was obtained for CBE-2 (TMC=285345.0 ± 3737.67 milli Absorbance unit per second -mAu*s), followed by CBE-1 (TMC=242965.2 ± 3411,5 mAu*s) and CBE-3 (TMC=108000.2 ± 4530.03 mAu*s). Despite NaDES still appeared as promising solvents, the hydroalcoholic mixtures gave the best recoveries; at the same time, innovative MAE showed to be a sustainable approach, providing high yield within few minutes.

Rotational symmetric solar system shaped triple band perfect metamaterial absorber for S-, C-, and X-band application

This article offers a metamaterial absorber of solar system shaped design for S-, C-, and X-band using a simple and symmetric structure. This innovative structure consists of two split ring resonator (SRRs) and two circular shape metal strips with a metal disc in the center. The ground metallic layer and upper patches are disjoint by flame retardant dielectric FR-4 (lossy) material of thickness 1.6 mm. Copper (annealed) of depth 0.035 mm is used for the all patches as well as the ground layer. The electrical dimension of the unit cell is 0.1006 λ × 0.1006λ which is calculated at the lower frequency 3.02 GHz. Computer simulation technique (CST) microwave studio is used to derive the numerical results. The simulation result yields three resonance peaks at 3.02, 5.71 and 8.36 GHz with the absorption 99.86%, 97.58% and 97.46%, respectively. The electric field, magnetic field and the surface current distribution are studied to comprehend the absorption mechanism. The reflection coefficient (S11) is also investigated by advanced design system (ADS) electrical equivalent circuit. This unique design of metamaterial absorber (MMA) unit cell is finalized through some parametric studies. The simulated results are also validated by ADS with electrical equivalent circuit and different array orientation. Unit cell, 1 × 2, 2 × 2 and 4 × 4 array of the unit cell are fabricated for measurement purposes. The measurement is carried out with the help of programmable network access (PNA) of Agilent N5227 with waveguide ports. The S-, C-, and X-band are mainly used for satellite communication and radar system. S-band is used for the shipping, aviation and space industries for its efficiency as a conduit for supplying vital real-time data whereas, C band is used for many wireless communication like satellite transmissions, Wi-Fi devices, mobile communication and weather forecasting system. X band is a radar sub-band which is utilized in civil, military, weather monitoring, air traffic control, maritime vessel traffic control, defense tracking.