Maximum Change Research Articles

Effect of Single Low-Dose Dexamethasone on Peri-operative Blood Glucose Levels

Background: Post-operative nausea and vomiting (PONV) is the second most common complaint reported after surgery with an incidence of 30%-80%. PONV is associated with numerous morbidities, hence prevention is beneficial. Dexamethasone is used as a prophylactic anti-emetic agent, however, being a corticosteroid, it could cause hyperglycaemia which is associated with a number of other adverse effects. Objectives: To study the effect of a single low-dose intravenous dexamethasone given as a prophylactic anti-emetic agent on perioperative blood glucose levels. Methods: Eighty-eight women who had elective myomectomy or hysterectomy under combined spinal-epidural (CSE) anaesthesia were randomised into two groups of 44 each. Following baseline blood glucose estimation, one group had 4 mg (1 ml) of intravenous dexamethasone 1-2 seconds after blood glucose check while the control group had 1 ml of normal saline. Blood glucose was measured every hour intra-operatively and two-hourly post-operatively till 12 hours after drug administration. Nausea, vomiting, dyspepsia, pain, motor block duration and urinary output were assessed hourly. Results: The mean maximum change in blood glucose from baseline in the dexamethasone group was statistically significantly higher than in the control group, 51.00±26.57 mg/dl vs. 35.80±25.71 mg/dl (p = 0.007) so also was the mean maximum blood glucose, 153.93±31.63 mg/dl vs. 139.52±28.95 mg/dl (p = 0.028) respectively. Conclusion: Intravenous dexamethasone at a single, low-dose (4 mg) used as a prophylaxis for nausea and vomiting is associated with significant increase in blood glucose concentration.

Revealing Bipolar Photoresponse in Multiheterostructured WTe2-GaTe/ReSe2-WTe2 P-N Diode by Hybrid 2D Contact Engineering.

The van der Waals (vdW) heterostructures based on two-dimensional (2D) semiconducting materials have been thoroughly investigated with regard to practical applications. Recent studies on 2D materials have reignited attraction in the p-n junction, with promising potential for applications in both electronics and optoelectronics. 2D materials provide exceptional band structural diversity in p-n junction devices, which is rare in regular bulk semiconductors. In this article, we demonstrate a p-n diode based on multiheterostructure configuration, WTe2-GaTe-ReSe2-WTe2, where WTe2 acts as heterocontact with GaTe/ReSe2 junction. Our devices with heterocontacts of WTe2 showed excellent performance in electronic and optoelectronic characteristics as compared to contacts with basic metal electrodes. However, the highest rectification ratio was achieved up to ∼2.09 × 106 with the lowest ideality factor of ∼1.23. Moreover, the maximum change in photocurrent (Iph) is measured around 312 nA at Vds = 0.5 V. The device showed a high responsivity (R) of 4.7 × 104 m·AW-1, maximum external quantum efficiency (EQE) of 2.49 × 104 (%), and detectivity (D*) of 2.1 × 1011 Jones at wavelength λ = 220 nm. Further, we revealed the bipolar photoresponse mechanisms in WTe2-GaTe-ReSe2-WTe2 devices due to band alignment at the interface, which can be modified by applying different gate voltages. Hence, our promising results render heterocontact engineering of the GaTe-ReSe2 heterostructured diode as an excellent candidate for next-generation optoelectronic logic and neuromorphic computing.

Morphological evidence of an explosive eruption event in October 2023 at Sofu Seamount in the Izu-Bonin Arc

Sofu Seamount is one of the poorly studied submarine edifices in the Izu-Bonin Arc. There is no known historical record of volcanic activity, thus its eruptive history and volcanic features are completely unknown. However, on October 9, 2023, at least 14 T-phases originating near Sofu Seamount were observed. An 80 km-long raft of floating pumice was observed off Sofu Seamount on October 20. These spatially and temporally coherent observations indicate that an eruption occurred from a deep seafloor vent somewhere near Sofu Seamount. In order to investigate the origin of this submarine eruption, we collected new bathymetric data in 2024 and compared it with older bathymetric data collected in 2022, 2007 and 1987. The bathymetric comparison revealed evidence for explosive eruptions at Sofu Seamount between 2022 and 2024. During this time, a crater, 1.6 km wide and 400 m deep, was formed at the pre-existing central cone on the western part of Sofu Seamount, whose pre-eruption summit depth was 737 m. The maximum negative depth change was 451 m and a volume of 430 × 106 m3 was removed due to the crater formation. A dome-like structure, 1 km wide and 100 m high was constructed northeast of the crater, part of which collapsed as a result of the crater formation. The volcanic products were transported over 6 km downslope and emplaced on the adjacent seafloor where positive depth changes up to 75 m were observed. Landslides also occurred around the crater. The largest slide on the northern flank formed a slide scar that is 3.8 km long and 1 km wide. Here, the maximum negative depth change was 148 m and 140 × 106 m3 of material was removed. The slide materials were deposited downslope where positive depth changes up to 61 m were observed. Considering the occurrence of the earthquake swarm on October 2–8, 2023 and T-phase swarm on October 9, the timing of the eruption can be constrained within October 2023.An analysis of volcanic and tectonic morphology reveals a distinct tectonic influence on volcanism at Sofu Seamount. Sofu Seamount is located in a back-arc rift zone where the N–S trending Torishima and Sofu Rifts have formed. The new bathymetric data showed that the rifts have an asymmetric structure and can be divided into two segments, which are identified here as inner and outer rifts. The inner rifts are bounded by steeper fault scarps that have experienced more subsidence than the outer rifts. The western part of Sofu Seamount, where the eruption occurred, is located within the inner rifts, and is heavily dissected by rifting-related normal faults, while the eastern part is located outward of the inner rifts and is not dissected by faults. The October earthquake swarm was more concentrated in the area of the inner rifts and some large earthquakes showed normal fault focal mechanisms with a tension axis approximately in E–W direction. Our morphological observations combined with recent seismic events show that the inner rifts are the currently active tectonic structures and young volcanism at Sofu Seamount is controlled by the back-arc rifting of the Izu-Bonin Arc.

The Influence of Sn Addition on the Magnetocaloric Effects, Magnetic and Mechanical Properties of Fe<sub>2</sub>P-Type Mn-Fe-P-Si Compounds

Mn1.25Fe0.65-xSnxP0.50Si0.50 (0, 0.02, 0.04, 0.05, 0.06, 0.08, 0.09, 0.10, 0.20) series compounds were prepared by mechanical alloying and solid-phase sintering, and their mechanical and magnetic properties were studied. The XRD measurement results show that all the compounds crystalize in Fe2P hexagonal structures, with a space group of P-62m. With the increase in Sn content, the compressive strength is significantly improved, the Curie temperature of the compound gradually decreases, and the nature of magnetic transition is tuned from a weak to strong first-order one, which is confirmed by the increase of thermal hysteresis of the compounds. The maximum magnetic entropy change of the compound increases from 9.3 J/kg·K at x = 0 to 17.2 J/kg·K at x = 0.04 under a magnetic field change of 0 - 3 T.

Inverse and conventional dual magnetocaloric effects in Ni substituted Y-type Sr2Zn2-xNixFe12O22 hexaferrites

The effects of Ni substitution on magnetic and magnetocaloric effect (MCE) are investigated in polycrystalline Y-type hexaferrites of Sr2Zn2-xNixFe12O22 (x = 0.0, 0.8, and 2.0). With the increasing of temperature, the M-T curves indicate successive magnetic structure transitions exist in Sr2Zn2-xNixFe12O22 (x = 0.0, 0.8, and 2.0), which play significant roles in MCE behaviors. As the Ni2+ doping ratio increases, the shape of −ΔSM−T curves near room temperature evolves gradually from a table-like to a peak-like form. Particularly, a significant contrast between CMCE and IMCE is observed below 100 K, whose behavior can be inherently exploited for heat sink in magnetic refrigeration applications. Among the samples in this series, Sr2Zn1.2Ni0.8Fe12O22 plays the best CMCE and IMCE performances, with the maximum magnetic entropy change (−ΔSMmax) values of 0.78 J/kg K at 354 K and −0.56 J/kg K at 16 K for ΔH=50kOe , respectively. Our work demonstrates that Sr2Zn2-xNixFe12O22 hexaferrites have great potential to be tailored for magnetic refrigeration with special needs such as different operating temperature zones, Ericsson cycle or heat sink at refrigeration.

A Rapid Increase in Serum Lactate Levels after Cardiovascular Surgery Is Associated with Postoperative Serious Adverse Events: A Single Center Retrospective Study.

Hyperlactatemia is a common predictive factor for poor post-cardiovascular surgery outcomes. However, it is not well understood whether the rapid postoperative lactate level elevation in a short period of time is associated with patient outcomes. Herein, we investigated the relationship between the degree of change in serum lactate levels and postoperative serious adverse events (PSAEs), including mortality, within 24 h of cardiovascular surgery. In this retrospective study, we evaluated the relationship between a rapid serum lactate level increase and PSAEs after open-heart and major vascular surgery. We divided the patients into those with and without PSAEs. Univariate and multivariate analyses were performed to evaluate the association between PSAEs and rapid lactate level increases. We enrolled 445 patients; 16% (n = 71) had PSAEs. The peak lactate levels during the first 24 h of intensive care unit (ICU) stay were higher in patients with PSAEs than in those without. The maximum change in lactate levels between two consecutive lactate measurements during the first 24 h after ICU admission was higher in patients with PSAEs than in those without. A multivariate logistic regression analysis revealed that changes in lactate levels of 2 mmol/L or more between two consecutive lactate measurements were associated with PSAEs. ICU peak lactate levels of 3 mmol/L or more were not associated with PSAEs. Rapid serum lactate level increases of 2 mmol/L or more during the first 24 h of ICU admission post-cardiovascular surgery are associated with PSAEs.

Crystal growth and magnetocaloric effect of Li9Fe3(P2O7)3(PO4)2 with Kagome lattice

With the growing demand for low-temperature technologies, magnetic refrigeration, which is based on magnetocaloric effect (MCE) of magnetic materials, has attracted increasing attention. In this work, Li9Fe3(P2O7)3(PO4)2 (LFPP) crystals have been grown by the high-temperature flux method. The crystal structural characterization is analyzed, and its magnetocaloric effect (MCE) is in detail investigated for the first time. The maximum magnetic entropy changes (−ΔSM) of LFPP under a field change of 0–7 T are determined to be 4.6 J/kg·K (H⊥c) and 4.1 J/kg·K (H//c) at 4 K and 5 K, respectively. The slow decrease of −ΔSM around the phase transition temperature implies that LFPP has a large refrigeration temperature range.

An In-Depth Look at Rising Temperatures: Forecasting with Advanced Time Series Models in Major US Regions

With growing concerns over climate change, accurately predicting temperature trends is crucial for informed decision-making and policy development. In this study, we perform a comprehensive comparative analysis of four advanced time series forecasting models—Autoregressive Integrated Moving Average (ARIMA), Exponential Smoothing (ETS), Multilayer Perceptron (MLP), and Gaussian Processes (GP)—to assess changes in minimum and maximum temperatures across four key regions in the United States. Our analysis includes hyperparameter optimization for each model to ensure peak performance. The results indicate that the MLP model outperforms the other models in terms of accuracy for temperature forecasting. Utilizing this best-performing model, we conduct temperature projections to evaluate the hypothesis that the rates of change in temperatures are greater than zero. Our findings confirm a positive rate of change in both maximum and minimum temperatures, suggesting a consistent upward trend over time. This research underscores the critical importance of refining time series forecasting models to address the challenges posed by climate change and supporting the development of effective strategies to mitigate the impacts of rising temperatures. The insights gained from this work emphasize the need for continuous advancement in predictive modeling techniques to better understand and respond to the dynamics of climate change.

Insight into the Structural and Magnetic Properties of PrZnSi and NdZnSi Compounds Featuring Large Low-Temperature Magnetocaloric Effects.

The magnetocaloric (MC) and magnetic phase transition (MPT) properties in various types of rare earth (RE)-based magnetic materials have been intensively investigated recently, which are aimed at developing suitable MC materials for low-temperature cooling applications and better elucidating their inherent physical properties. We herein provide a combined experimental and theoretical investigation into two new light RE-based magnetic materials, namely, PrZnSi and NdZnSi compounds, regarding their structural, magnetic, MPT, and low-temperature MC properties. Both of these compounds crystallize in an AlB2-type hexagonal structure with a symmetry of the crystallographic space group P6/mmm and reveal a typical second-order-type MPT with ordering temperatures (TC) at approximately 13.5 and 18.5 K for PrZnSi and NdZnSi compounds, respectively. Moreover, they all exhibit large reversible low-temperature MC effects and remarkable performances, which are identified by the parameters of maximum magnetic entropy changes, relative cooling power, and temperature-averaged entropy change (temperature lift 5 K). The deduced values of these MC parameters under a magnetic field change of 0-7 T reach 16.3 J/kgK, 294.46 J/kg, and 15.79 J/kgK for PrZnSi and 15.4 J/kgK, 284.84 J/kg, and 14.95 J/kgK for NdZnSi, respectively, which are evidently better than those of most updated light RE-based magnetic materials with remarkable low-temperature MC performances, indicating that PrZnSi and NdZnSi compounds hold potentials for practical cooling applications.

Multifunctional carbon Fiber@TiO2/C aerogels derived from MXene for pressure tunable microwave absorption

Developing microwave absorption (MA) materials with dynamically tunable performance stands as a pivotal endeavor to fulfill the escalating demands of electronic devices and military equipment in complex electromagnetic environments. This study presents advanced hierarchical CF@TiO2/C aerogels with pressure tunable MA performance, engineered through a novel in-situ oxidation process of MXene on carbon fiber (CF) substrates. This process facilitates the formation of a two-dimensional (2D) TiO2/C hybrid layer, which significantly enhances the polarization loss capabilities of the aerogels while maintaining excellent mechanical resilience. The unique architecture of these aerogels facilitates the modulation of their electrical conductivity and permittivity via pressure, thus enabling dynamically adjustable MA performance. Upon compression (50 %), the CF@TiO2/C aerogels showcase an outstanding effective absorption bandwidth (EAB) of 7.84 GHz, accompanied by a remarkable minimum reflection loss (RLmin) of −74.38 dB. Notably, the EAB of CF@TiO2/C aerogels can be precisely tuned from 4 to 18 GHz (covering the C-band, X-band, and Ku-band), with maximum changes in RLmin values (ΔRLmin) reaching as high as 59.30 dB, indicating substantial tunability under varying pressure. Moreover, the CF@TiO2/C aerogels also demonstrate outstanding thermal insulation and pressure sensing performance, highlighting their potential for multifunctional applications. This research not only sheds light on the intricate interplay between nanostructured materials and electromagnetic waves interactions but also sets a new strategy for the design of multifunctional, tunable microwave absorbers suitable for complex electromagnetic environments in modern electronic and military applications.

Multicaloric response tuned by electric field in cylindrical MnAs/PZT magnetoelectric composite

The possibility observation of the electric field controlled multicaloric response through quasi-isostatic compression as a result of the converse piezoelectric effect was demonstrated on the cylindrical type magnetoelectric composite MnAs/PZT. It was shown that an electric voltage of 100 V corresponding to an electric field of E ∼0.3 kV/mm applied to the walls of the piezoelectric component PZT of the MnAs/PZT composite contributes to an increase in the maximum adiabatic temperature change by 0.2 K in the temperature range of the magnetostructural phase transition of MnAs ∼317 K at a magnetic field change of 1.8 T. Numerical analysis using the finite element method has shown that an electric field voltage of 100 V is capable of creating a quasi-isostatic mechanical stress in the region inside a cylindrical PZT tube of ∼3 MPa. Moreover, in the region of weak pressures up to 10 MPa, the contribution to the total adiabatic temperature change from piezo-mechanical compression linearly depends on the electrical voltage that can be used for control by magnetic and caloric properties of multicaloric materials.

Long-term stability of a PTW 34070 large-area parallel ionization chamber in clinical proton scanning beams.

In the modeling of beam data for proton therapy planning systems, absolute dose measurements are performed utilizing a Bragg peak chamber (BPC), which is a parallel-plate ionization chamber. The long-term stability of the BPC is crucial for ensuring accurate absolute dose measurement. The study aims to assess the long-term stability of the BPC in clinical proton pencil beam scanning delivery. The long-term stability evaluation focused on the BPC-Type 34070 (PTW Freiburg, Germany), utilizing clinical proton scanning beams from December 2022 to November 2023. Monthly investigations were conducted to evaluate the response and cross-calibration factor of the BPC and a reference chamber, employing the spread-out Bragg peak (SOBP) field. Additionally, assessments were made regarding the BPC's response to monoenergetic beams, along with an examination of the impact of polarity and ion recombination on the BPC. The response and cross-calibration factor of the BPC varied up to 1.9% and 1.8%, respectively, while the response of the reference chamber remained within a 0.5% range. The BPC's response to the mono-energetic beams varied up to 2.0% across all energies, demonstrating similar variation trends in both the SOBP field and mono-energetic beams. Furthermore, the variations in polarity and ion recombination effect remained stable within a 0.4% range throughout the year. Notably, the reproducibility of the BPC remained high for each measurement conducted, whether for the SOBP field or mono-energetic beams, with a maximum deviation observed at 0.1%. The response and cross-calibration factor of the BPC demonstrated significant variations, with maximum changes of 1.9% and 1.8%, respectively. However, the reproducibility of the BPC remained consistently high for each measurement. It is recommended that when conducting absolute dose measurements using a BPC, its response should be compared and corrected against the reference chamber for each measurement.

Abstract B012: Randomized phase II trial of two different nutritional approaches for patients receiving treatment for their advanced pancreatic cancer: initial results of safety and feasibility of the medically supervised ketogenic diet

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by stromal fibrosis, hypoxia, and nutritional deprivation. Nutritional metabolic interventions may fundamentally change the tumor microenvironment and improve outcomes. A ketogenic diet (KD) (lower carbohydrate, moderate protein, higher fat) can significantly reduce glucose and insulin and stimulate ketogenesis. Triplet chemotherapy with gemcitabine/cisplatin/nab-paclitaxel has been associated with a median OS 16.4 months, PFS 10.1 months in patients with metastatic PDAC in the first-line setting. Recently, KD plus triplet chemotherapy was shown to inhibit murine pancreatic KPC tumor growth and prolong animal survival over chemotherapy alone (Yang et al, Med, 2022). Tumor growth inhibition was associated with glucose depletion, altered TCA substrate use and NADH elevation. Methods: In this Phase II trial, patients with treatment-naive metastatic PDAC were randomized to triplet chemotherapy with a medically supervised ketogenic diet (MSKD) or continuing their usual diet (non-MSKD). The MSKD is supported by Virta Health, who offers tracking of daily ketone (beta-hydroxybutyrate, BHB) and glucose levels, a web-based application, education, and communication with a remote care team to ensure sustained nutritional ketosis (BHB 0.5–3.0mM). Patients with BMI < 18, type 1 DM or history of DKA were excluded. Primary endpoint was PFS. Secondary endpoints: DCR (PR+CR+SD ≥ 9 weeks), change in CA 19-9 (CA125, CEA if not CA 19-9 expressers), average fasting insulin levels, HbA1c, body weight, gut microbiome, serum metabolites, QOL (QLQ- C30). Results: A total of 36 patients with untreated metastatic PDAC were enrolled. Among 32 evaluable patients (median age 65.9 years; 53% male), 16 were randomized to each arm. Both groups had similar baseline weight, HgbA1c, insulin and BHB levels (all p>0.05). Nine patients had type 2 DM; 6 required insulin. In the MSKD group, 15/16 achieved nutritional ketosis at any point during the study, with mean BHB of 0.57 mM (95% CI 0.40–0.73) and median proportion of days in ketosis of 39.4% (range 0-95.8%) by daily ketone tracking. Lab data showed significantly higher mean ± SD maximum change in BHB in the MSKD (0.5 ± 0.9 mmol/L) versus non-MSKD (–0.2 ± 0.3 mol/L) group (p = 0.018). There were no significant differences between groups in maximum change in weight, HbA1C, or insulin (all p > 0.05). The most common MSKD-related adverse events were Gr 1-2 fatigue (n=4), constipation (n=3), weight loss (n=3), and none stopped MSKD due to adverse events.Conclusion: A medically supervised ketogenic diet is feasible in patients with metastatic PDAC receiving triplet chemotherapy, with median proportion of days in ketosis of 39.4% and an acceptable safety profile. The MSKD is associated with comparable changes in insulin and HgbA1c levels compared to the non-MSKD diet, and sustained ketosis does not result in significantly greater weight loss. MSKD warrants further prospective exploration and analyses of the primary endpoint and correlative studies are ongoing. Citation Format: Gayle S Jameson, Erkut Borazanci, Diana L Hanna, Caroline GP Roberts, Meredith S Pelster, Richard C Frank, Angela T Alistar, Julia E Wiedmeier-Nutor, Sandra D Algaze, Brandon Fell, Sarah J Hallberg, Denise J Roe, Betsy C Wertheim, Derek Cridebring, Joshua D Rabinowitz, Stephen Gately, Daniel D Von Hoff, Drew W Rasco. Randomized phase II trial of two different nutritional approaches for patients receiving treatment for their advanced pancreatic cancer: initial results of safety and feasibility of the medically supervised ketogenic diet [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B012.

Integrated structural and functional analysis of Ba1-xSrxTiO3-Bi0.5Na0.5TiO3 ceramics: Insights into energy storage and electrocaloric performance

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξmax = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration.

Assessing the Variability of Aerosol Optical Depth Over India in Response to Future Scenarios: Implications for Carbonaceous Aerosols

AbstractAir pollution caused by various anthropogenic activities and biomass burning continues to be a major problem in India. To assess the effectiveness of current air pollution mitigation measures, we used a 3D global chemical transport model to analyze the projected optical depth of carbonaceous aerosol (AOD) in India under representative concentration pathways (RCP) 4.5 and 8.5 over the period 2000–2100. Our results show a decrease in future emissions, leading to a decrease in modeled AOD under both RCPs after 2030. The RCP4.5 scenario shows a 48%–65% decrease in AOD by the end of the century, with the Indo‐Gangetic Plain (IGP) experiencing a maximum change of 25% by 2030 compared to 2010. Conversely, RCP8.5 showed an increase in AOD of 29% by 2050 and did not indicate a significant decrease by the end of the century. Our study also highlights that it is likely to take three decades for current policies to be effective for regions heavily polluted by exposure to carbonaceous aerosols, such as the IGP and eastern India. We emphasize the importance of assessing the effectiveness of current policies and highlight the need for continued efforts to address the problem of air pollution from carbonaceous aerosols, both from anthropogenic sources and biomass burning, in India.

Eigenbin compression for reducing photon-counting CT data size.

Photon-counting CT (PCCT) systems acquire multiple spectral measurements at high spatial resolution, providing numerous image quality benefits while also increasing the amount of data that must be transferred through the gantry slip ring. This study proposes a lossy method to compress photon-counting CT data using eigenvector analysis, with the goal of providing image quality sufficient for applications that require a rapid initial reconstruction, such as to confirm anatomical coverage, scan quality, and to support automated advanced applications. The eigenbin compression method was experimentally evaluated on a clinical silicon PCCT prototype system. The proposed eigenbin method performs principal component analysis (PCA) on a set of PCCT calibration measurements. PCA finds the orthogonal axes or eigenvectors, which capture the maximum variance in the N dimensional photon-count data space, where N is the number of acquired energy bins. To reduce the dimensionality of the PCCT data, the data are linearly transformed into a lower dimensional space spanned by the M<N eigenvectors with highest eigenvalues (i.e., the vectors that account for most of the information in the data). Only M coefficients are then transferred per measurement, which we term eigenbin values. After transmission, the original N energy-bin measurements are estimated as a linear combination of the M eigenvectors. Two versions of the eigenbin method were investigated: pixel-specific and pixel-general. The pixel-specific eigenbin method determines eigenvectors for each individual detector pixel, while the more practically realizable pixel-general eigenbin method finds one set of eigenvectors for the entire detector array. The eigenbin method was experimentally evaluated by scanning a 20cm diameter Gammex Multienergy phantom with different material inserts on a clinical silicon-based PCCT prototype. The method was evaluated with the number of eigenbins varied between two and four. In each case, the eigenbins were used to estimate the original 8-bin data, after which material decomposition was performed. The mean, standard deviation, and contrast-to-noise ratio (CNR) of values in the reconstructed basis and virtual monoenergetic images (VMI) were compared for the original 8-bin data and for the eigenbin data. The pixel-specific eigenbin method reduced photon-counting CT data size by a factor of four with<5% change in mean values and a small noise penalty (mean change in noise of<12%, maximum change in noise of 20% for basis images). The pixel-general eigenbin compression method reduced data size by a factor of 2.67 with<5% change in mean values and a less than 10% noise penalty in the basis images (average noise penalty≤5%). The noise penalty and errors were less for the VMIs than for the basis images, resulting in<5% change in CNR in the VMIs. The eigenbin compression method reduced photon-counting CT data size by a factor of two to four with less than 5% change in mean values, noise penalty of less than 10%-20%, and change in CNR ranging from 15% decrease to 24% increase. Eigenbin compression reduces the data transfer time and storage space of photon-counting CT data for applications that require rapid initial reconstructions.

Excellent magnetocaloric effect near the hydrogen liquefaction temperature of a binary Er67.5Co32.5 metallic glass

We reported the excellent magnetocaloric effect of a binary Er67.5Co32.5 metallic glass (MG) near the hydrogen liquefaction temperature. The binary MG ribbon was fabricated by a melt-spinning method. The Er67.5Co32.5 alloy exhibits a better glass formability than most of other rare earth (RE)-Co binary alloys. The maximum magnetic entropy change (−ΔSmpeak) and refrigeration capacity (RC) of the Er67.5Co32.5 amorphous ribbon under 0–5 T reach to 17.47 J/(kg × K) near its Curie temperature (Tc, ∼ 11 K) and 472 J/kg, both of which are rather high among the RE-based MGs with a Tc around 10 K and imply the potential application perspective as magnetic refrigerants for hydrogen liquefaction. The magnetization as well as magnetocaloric behaviors of the binary MG were observed, and the mechanism involved was investigated.

Influences on the structure, magnetic, and magnetocaloric effect of La0.8Sr0.2MnO3 ceramics by Co ion doping with sol-gel method and first-principles calculations

This paper investigated the impact of Co ions doping on the structure, magnetic properties, and magnetocaloric effect for La0.8Sr0.2Mn1-xCoxO3 ceramics (LSMCO) by sol-gel method and first-principles calculations The use of first-principles calculations was provided for subsequent experiments. The sol-gel preparation of LSMCO ceramics and sintered at 950 °C for 10 h. It was shown that the samples' cell volume and lattice constants changed slightly with increasing Co2+ doping but remained a rhombohedral structure (No.167, R-3c space group) by statistics of TEM and XRD. The average particle size for the LSMCO ceramics ranged from 130 nm to 170 nm. LSMCO's chemical composition was verified by EDS and XPS and it was demonstrated that Co2+ was successfully doped. The oxidation state of La was found to be +3, Mn is a mixture of Mn3+ and Mn4+ valence states, and Co is a mixture of Co3+ and Co2+ valence states using XPS. In the vicinity of Tc, all samples presented the second-order magnetic phase transition from ferromagnetic to paramagnetic resorting to normalization and the Banerjee criterion. The Tc dropped from 292 K to 237 K with increasing Co2+ doping. The blocking temperature and the saturation magnetization were suppressed by the Co2+ substitution while the maximum magnetic entropy change of the LSMCO ceramics was observed to reduce as Co2+ increased. When the external magnetic field is 5 T, the La0.8Sr0.2Mn0.95Co0.05O3 ceramics has a Tc of 292 K and a maximum magnetic entropy change value of 3.47 J/(kg K).

Вплив комплексу біопротекторів на динаміку активності амінотрансфераз у сироватці крові за умов окремої та одночасної дії свинцю і фтору (експериментальні дослідження)

Lead and fluoride enter the human body individually and simultaneously through water, food, and air, disrupting metabolic processes in liver tissue. The sequential application of a bioprotective complex that reduce the negative effects of lead and fluoride has been insufficiently studied. The aim of the study is to investigate the changes over time in the activity of alanine aminotransferase and aspartate aminotransferase in the blood serum of laboratory animals under prolonged separate and simultaneous exposure to lead and fluoride, without application of bioprotective agents and during the sequential addition of pectin, pectin with calcium, and a complex of pectin, calcium, and antioxidants to the standard animal diet. Materials and Methods. Four clinical trial series were conducted on white rats, each following an orthogonal design 22. Aqueous solutions of Pb(NO3)2 and NaF were administered orally separately and simultaneously over 30 days: in the first series without bioprotective agents, in the second with pectin, in the third with pectin and calcium, and in the fourth with a complex of pectin, calcium, and antioxidants – C, E, and β-carotene vitamins, and selenium. The activity of alanine and aspartate aminotransferases was measured in blood serum on days 3, 15, and 30 in the first and second series of experiments, and on day 30 in the third and fourth series. Results. Separate and simultaneous oral administration of lead and fluoride to white rats leads to increased activity of alanine and aspartate aminotransferases in blood serum. The maximum changes were observed at the end of the experiment. The protective role of pectin alone under long-term fluoride expos ure and simultaneous exposure to lead and fluoride was not sufficiently effective. Concurrent intake of calcium and pectin significantly reduced the increase in transaminase activity, indicating an improvement in the metabolic and functional state of the liver. The application of the bioprotective complex restored the aminotransferase activity in blood serum. Conclusions. The complex of pectin with calcium and antioxidants can be considered an optimal means of correcting aminotransferase activity in blood serum under prolonged separate and simultaneous exposure to lead and fluoride.

Stepwise dechlorination and co-pyrolysis of poplar wood with dechlorinated polyvinyl chloride: Synergistic effect and products distribution

With the combination of stepwise dechlorination and co-pyrolysis techniques, this study conducted polyvinyl chloride (PVC) dechlorination experiments and co-pyrolysis experiments of poplar wood (PW) with dechlorinated polyvinyl chloride (DPVC) by thermogravimetric analysis and a fixed bed reactor. Stepwise pyrolysis effectively removed Cl from PVC with a dechlorination efficiency of 99.84 % at 360 °C for 30 min. Thermogravimetric tests and thermokinetic variables were employed to describe the co-pyrolysis process's thermodynamic behavior, where co-pyrolysis significantly diminished the activation energy of the initial pyrolysis stage (9.65–21.62 kJ/mol) and increased the reaction rate (0.02–0.09 %/°C). The synergistic effect of co-pyrolysis enhanced the yield and quality of liquid oil and reduced the solid residue rate, with the maximum change in solid residue rate (−2.36 wt%) occurring at PW:DPVC = 3:7. The optimal conditions for the synergistic effect are a raw material ratio of 3:7 at 500 °C. Co-pyrolysis efficiently reduced the content of oxygen-containing compounds of phenols, ketones, and acids in oil, and elevated the selectivity of aromatics. The research methods avoid the drawbacks of bio-oil and plastic oil and improve the quality of pyrolysis oil in a concise and efficient manner, which provides some new ideas for the resource and clean utilization of municipal waste.