Impact Of Ca Research Articles

Exploring the catalytic conversion of aromatic model compounds of coal pyrolysis over Ca(OH)2

The distribution of pyrolysis products from aromatic model compounds in coal catalyzed by Ca(OH)2 was investigated at the molecular level. The composition and relative abundance of the pyrolysis products from coal were analyzed using Py-GC/MS. The rapid pyrolysis products of coal at 600 °C consisted of phenols (15.94 %), non-phenolic oxygenated compounds (25.31 %), aliphatics (49.03 %), aromatic compounds (21.74 %), and other compounds (0.03 %). Six representative aromatic model compounds (2-methoxy-4-methylphenol, p-cresol, 2,4-dimethylphenol, o-cresol, guaiacol, and catechol) were selected. The pyrolysis process of model compounds was primarily the cleavage of C-O and C-C bonds, which resulted in the formation of methoxy and methyl radicals. The results revealed that Ca(OH)2 undergoes acid-base reactions with -OH, thereby increasing the stability of the model compounds. Notably, the impact of Ca(OH)2 on the composition and distribution of pyrolysis products was significantly more pronounced in aromatic compounds containing both -OCH3 and -OH compared to those containing solely -OH. The formation pathways of pyrolysis products involving guaiacol and Ca(OH)2 were elucidated through density functional theory (DFT) calculations, demonstrating that Ca(OH)2 could facilitate more free radicals release and the conversion of model compounds. This study contributes to the understanding of the transformation of aromatic compounds during coal pyrolysis at the molecular level.

Hydrothermal transformation of fly ash to tobermorite or katoite: Impact of Ca and Si concentration in the liquid phase without alkali activation

In the study of hydrothermal conversion of fly ash to calcium silicate hydrates (C–S–H), the concentration of Ca and Si in the liquid phase plays a vital role in determining the hydrothermal transformation results. This paper selected a fly ash as a research object, which can leach a high Si concentration into the solution in the hydrothermal process even in a slight alkaline solution, based on a new finding when studying the alkali dissolution kinetics of different fly ashes. To explore the effects of Ca and Si concentrations in the liquid phase on the hydrothermal transformation of fly ash to tobermorite or katoite, Na2SiO3 (Na2O·xSiO2·yH2O) and CaSO4 were used to change the concentration of Si and Ca in the liquid in the hydrothermal system. Characterization methods such as XRD, SEM, infrared spectroscopy, and solid-state nuclear magnetic resonance indicated that a little more concentration of Si can promote the transformation from fly ash to tobermorite and persuade the conversion of the Si–O tetrahedron in C–S–H from Q2 to Q3 and Q4. However, too high a liquid Si concentration made the hydrothermal product change to colloidal calcium silicate. On the other hand, a high Ca concentration in the liquid was found to lead to the conversion of the hydrothermal product from tobermorite to katoite. According to the above results, the deep transformation from fly ash to tobermorite under the conditions of a low temperature of 160 °C and no extra alkali addition was achieved by the induction of a small quantity of Na2SiO3.

Impact of Ca, Al, and Mg on reaction kinetics, pore structure, and performance of Fe‐rich alkali‐activated slag

AbstractAlkali‐activated materials can be formed by alkali‐activation of Fe‐rich non‐ferrous metallurgical slags (AA‐NFMS). To study NFMS in AA‐NFMS systematically, five NFMS were synthesized, with different CaO (6–16 wt%), Al2O3 (7–11 wt%), and MgO (0–4 wt%) contents, while keeping the same FeOx/SiO2 molar ratio. The effect of slag chemistry and the alkali ions (Na+/K+ = 0, 0.5, and 1) in alkali‐activating solution on the reaction kinetics, compressive strength (3, 7, and 28 days), and pore structure of AA‐NFMS was investigated. The reactivity up to 3 days was evaluated via isothermal calorimetry, and the pore structure was analyzed via mercury intrusion porosimetry. Higher Al/Si in the slag showed higher reactivity, higher compressive strength, and lower total porosity of the AA‐NFMS. Higher Ca/Si yielded lower cumulative heat after 3 days and decreased early compressive strength but higher strength after 28 days of curing. Ca replacement by Mg led to faster reaction kinetics but inferior mechanical properties and increased porosity. Increased K+ concentration in the activator resulted in higher reactivity and compressive strength despite the higher total porosity. Empirical model fitting using JMP software revealed that K+/(N++ K+) in the activator, Ca/Si, and (Ca+Mg)/Si in NFMS are significant factors that affect the strength of AA‐NFMS.

Multifunctional behavior of solid-state derived Ca-doped BaFe0.5Nb0.5O3 complex perovskite system

In recent years, BaFe0.5Nb0.5O3 (BFN) complex perovskite has been projected as one of the promising Pb-free materials for energy storage applications. The primary goal of this research work is to look into the impact of Ca on the structural, electrical, and magnetic behavior of BFN and examine its suitability for multifunctional applications. The conventional solid-state reaction route is followed to prepare the desired Ba0.88Ca0.12Fe0.5Nb0.5O3 complex perovskite sample. The analysis of X-ray diffraction data reveals that the sample crystallizes in monoclinic symmetry and belongs to the C1m1 space group. The micrograph obtained through scanning electron microscopy indicates the dense surface morphology of the sample. The elemental examination through energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirms the purity and reveals information regarding the chemical states of the involved elements. The complex impedance and dielectric studies conducted over a wide frequency and temperature range infer that the sample possesses semiconducting as well as capacitive properties. The magnetic response monitored at room temperature confirms the ferromagnetic behavior of the sample. Based on all the investigations carried out, it can be stated that the synthesized complex perovskite can be used for fabricating tunable microwave devices, energy storage devices, magnetic storage devices, etc.

Application of fluorescent transients to indicate nutrient deficiencies in a microalga Nannochloropsis oceanica

Here we studied the effects of nutrient deficiency, focusing on Ca, N, S, Mg, Fe, on photosynthetic performance of Nannochloropsis oceanica to determine the abilities of fluorescence transients to detect nutrient limitation. We conducted a two-level (replete/deplete) fully factorial experiment for each of 5 nutrients and found different responses to nutrient limitation. A potential indicator of N limitation was trapped energy per reaction center (TRO/RC), as the synthesis of photosynthetic reaction center (RC) declined under N deficiency and eventually the ratio of TRO/RC increased. Photosystem II performance measured by performance index (PIABS) was not compromised under Fe, S and Mg deficiency, whereas the impact of Ca and N was critical. Although interactive nutrient interactions on photosynthetic parameters were observed, relationships were established between net reaction closure (MO) and Mg; dissipated energy flux per RC (DIO/RC) and S; and average quantum yield of photochemistry (ΦPav) and Ca.

Impact of Ca(BO2)2 Doping on High-Tc Phase Formation and Transport Properties of Bi(Pb)-2223 Superconductor

Proper Doping of a high-temperature superconductor (HTS) Bi(Pb)-2223 is an effective route to prepare Bi(Pb)-2223 HTS with enhanced transport characteristics. In this paper, we studied the impact of Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> doping on high-T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> phase formation kinetics and transport critical current density of Bi(Pb)-2223. Samples with a nominal composition of Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.7</sub> Pb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Ca <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-x</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> [Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> , x = 0 −0.15 were prepared by the solid-state reaction method. The phase evolution of the prepared materials was studied by X-ray diffraction analysis (XRD). The resistivity and critical current density were measured by the standard four-probe method. Scanning electron microscopy (SEM) combined with Energy Dispersive X-ray (EDX) microanalysis (SEM-EDX) was used to examine the microstructure and elemental composition of samples. The obtained results show that Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> doping leads to the promotion of the high-T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> phase formation and enhancement of the transport critical current density ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c)</i> in Bi(Pb)-2223 HTS.

Impact of cardiac amyloidosis on outcomes of patients hospitalized with heart failure

BackgroundAmyloidosis is a multi-systemic disease potentially leading to failure of affected organs. We aimed to investigate prevalence and prognostic implications of cardiac amyloidosis of any etiology on outcomes of hospitalized patients with heart failure (HF) in Germany. MethodsWe analyzed data of the German nationwide inpatient sample (2005–2018) of patients hospitalized for HF (including myocarditis with HF and heart transplantation with HF). HF patients with amyloidosis (defined as cardiac amyloidosis [CA]) were compared with those HF patients without amyloidosis and impact of CA on outcomes was assessed. ResultsDuring this fourteen-year observational period 5,478,835 hospitalizations for HF were analyzed. Amyloidosis was coded in 5,407 HF patients (0.1%). CA prevalence was 1.87 hospitalizations per 100,000 German population. CA patients were younger (75.0[IQR 67.0–80.0]vs.79.0[72.0–85.0]years, p < 0.001), predominantly male (68.9%) and had a higher prevalence of cancer (14.8% vs. 3.6%, p < 0.001). Adverse in-hospital events including necessity of transfusions of blood constituents (7.1% vs. 5.4%, p < 0.001) and cardio-pulmonary resuscitation (CPR, 2.7% vs. 1.4%; p < 0.001) were more frequent in CA. CA was independently associated with acute kidney failure (OR 1.40 [95%CI 1.28–1.52], p < 0.001), CPR (OR 1.58 [95%CI 1.34–1.86], p < 0.001), intracerebral bleeding (OR 3.13 [95%CI 1.68–5.83], p < 0.001) and in-hospital mortality between the 5 and 8th decade of life, but in-hospital mortality was strongly influenced by cancer. ConclusionsCA was identified as an independent risk factor for complications and in-hospital mortality in HF patients, whereby it has to be mentioned that amyloidosis subtypes could not differentiated in the present study. Physicians should be aware of this issue concerning treatments and monitoring of CA-patients.

Impact of Ca+ content and curing condition on durability performance of metakaolin-based geopolymer mortars

To overcome massive pollution and energy consumption resulting from cement production in addition to concrete’s durability problems, geopolymer concretes (GPC) and mortars (GPM) are recently gaining increasing interest. GPCs are manufactured based on different ingredients such as Fly Ash, GGBS, and other Alumina-Silicate rich materials and polymerized by using alkali activator. However, based on the major polymeric constituent material and curing condition, the properties of GPC are determined. In Egypt, metakaolin (MK) is available in several locations, which after calcination exhibits satisfactory pozzolanic activity. MK is a good replacement of cements in concrete and GPC as it consumes less fuel and produces much lower pollutants. In this research, the durability of MK mixes, that can be utilized in normal construction locations are investigated. Metakaolin based geopolymer mortars (MK-GPM) with up to 60% OPC are made to investigate the effect of OPC inclusion on durability related characteristics. The influence of curing conditions at ambient temperature (23 ± 2 °C) as well as at 60 °C heat curing is also investigated. Water transport properties are evaluated. Durability related characteristics in terms of change in weight and compressive strength with time after exposure for 10 weeks to chemical solution (10% MgSO4, H2SO4 (pH=3) and 10% NaCl). Furthermore, microstructure properties are investigated through X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with energy dispersive X-ray spectroscopy (EDS) to identify the phase and chemical composition. The results reveal that, heat curing of MK-GPM reduces its sorptivity by 9 ± 2% and water absorption by 13 ± 3%. On the other hand, the inclusion of OPC in MK-GPM (by more than 5%) increases water absorption and sorptivity and consequently reduces durability. Although, MK-GPM shows better durability when exposed to aggressive environmental attacks, incorporating cement up to 20% demonstrates better durability performance than OPC mortar. The study of the microstructure of tested mixes explains and confirms the experimental results.

The impact of CA 19-9 on survival in patients with clinical stage I pancreatic cancer.

606 Background: Standard of care for early-stage resectable pancreatic cancer (PC) includes a combination of surgical resection and chemotherapy. Frequently, CA 19-9 is used as a biomarker to monitor treatment effect and has prognostic significance. We evaluated the impact of CA 19-9 on overall survival (OS) in patients with clinical stage I PC (cT1N0 and cT2N0) utilizing the National Cancer Database (NCDB). Methods: The NCDB was queried between 2010 and 2014 to identify patients with clinical stage I PC. Patients who had missing or undocumented CA 19-9 value at diagnosis were excluded. Demographic and clinical characteristics were analyzed. Patients were stratified into two cohorts based on the CA 19-9 value at diagnosis – CA 19-9 &lt; 98 U/mL and CA 19-9 &gt; 98 U/mL. Univariable and multivariable analyses were performed, and variables associated with OS were identified. Kaplan-Meier survival curves were computed to compare the OS between the two cohorts. Results: A total of 12,480 patients met our inclusion criteria. A majority of patients were female (51.9%), white (84.4%), with a median age of 70 years. Nearly, half the patients received care in an academic/research program (49.5%). A majority of patients had tumors located in the head of the pancreas (71.9%), and received single-agent (35.1%) or multiagent (22.9%) chemotherapy. Over half the patients (6505 patients, 52.1%) had a CA 19-9 value &gt; 98 U/mL. A CA 19-9 value &gt; 98 U/mL in patients predicted a significantly shorter median OS of 12.1 months compared to 19.4 months in patients with a CA 19-9 &lt; 98 U/mL, p&lt;0.0001 (Table). The 5-year OS rate was 9.9% in patients with a CA 19-9 value of &gt; 98 U/mL compared to a 5-year OS rate of 18.1% for patients with a CA 19-9 value &lt; 98 U/mL. On multivariable analysis, CA 19-9 &gt; 98 compared to CA 19-9 &lt; 98 (HR 1.53, p&lt;0.001) and black race compared to white race (HR 1.10, p&lt;0.001) was associated with worse survival, whereas tumor location in the body and tail compared to the head (HR 0.82, p&lt;0.001), single-agent (HR 0.55, p&lt;0.001) and multiagent (HR 0.55, p&lt;0.001) chemotherapy compared to no chemotherapy, independently predicted improved OS. Conclusions: This is the first National Cancer Database study to demonstrate the prognostic value of CA 19-9 in patients with clinical stage I pancreatic cancer, with a value &lt; 98 U/mL predicting improved survival. Clinical stage I pancreatic cancer patients appear to derive a significant benefit from chemotherapy, including single and multiagent chemotherapy, irrespective of the CA 19-9 value.[Table: see text]

Prognostic significance of serum CA 19-9 response and dynamics in patients with intrahepatic cholangiocarcinoma undergoing surgical resection.

479 Background: Pre and post-operative elevation of serum CA 19-9 have been associated with poor outcomes and increased risk of recurrence in patients with resected intrahepatic cholangiocarcinoma (ICC). We sought to investigate the impact of CA 19-9 response and dynamics on survival for patients with ICC undergoing surgical resection. Methods: Clinicopathologic characteristics were abstracted from a prospectively maintained database at a tertiary cancer care center for patients with ICC undergoing surgical resection from 2003 to 2020. Exclusion criteria included CA 19-9 non-producers (≤ 1 U/mL at baseline), missing baseline/pre-operative or postoperative CA 19-9 value, or total bilirubin &gt; 2 mg/dL. Overall (OS) and recurrence-free survival (RFS) was compared among patients when categorized by baseline (neoadjuvant)/pre-operative (upfront surgery) and post-operative CA 19-9 values: normal (&gt; 1 to 37 U/mL), intermediate (&gt; 37 to 200 U/mL), and elevated (&gt; 200 U/mL). Patients were then stratified by perioperative CA 19-9 response (responder [non-normal to normal CA 19-9 OR 50% reduction in CA 19-9; normal to normal CA 19-9], non-responder [non-normal to non-normal CA 19-9 OR &lt; 50% reduction in CA 19-9; normal to non-normal CA 19-9]) and CA 19-9 dynamics (normal to normal, non-normal to normal, non-normal to non-normal, normal to non-normal CA 19-9 values). Results: A total of 112 patients were identified including 67 (59.8%) who underwent upfront surgery and 45 (40.2%) who received neoadjuvant therapy. Patients with a normal CA 19-9 at diagnosis had median RFS and OS durations of 61 and 163 months, followed by intermediate CA 19-9 (20 and 98 months) and elevated CA 19-9 (18 and 46 months, p = 0.308 RFS; p = 0.295 OS). Those who had a normal CA 19-9 post-operatively had the best median RFS and OS (46 and 163 months), followed by intermediate CA 19-9 (13 and 58 months) and elevated CA 19-9 (5 and 8 months, p = 0.059 RFS; p = 0.005 OS). When stratified by perioperative CA 19-9 response, responders had a median RFS of 36 vs. 13 months in non-responders (p = 0.143), and a median OS of 98 months vs. 88 months in non-responders (p = 0.077). Patients with normal CA 19-9 post-operatively had longer RFS/OS (normal to normal, 48/98 months; non-normal to normal, 30/not estimable months) than those who had non-normal CA 19-9 both pre- and post-operatively (non-normal to non-normal, 7/34 months, p = 0.018 RFS; p = 0.007 OS). Conclusions: Patients with normal CA 19-9 levels post-operatively, who had either normal or elevated CA 19-9 pre-operatively, had the greatest RFS and OS durations. A normal (or normalized) post-operative CA 19-9 may inform patient-centered decisions on adjuvant therapy and/or surveillance intensity.

Pu(iii) and Cm(iii) in the presence of EDTA: aqueous speciation, redox behavior, and the impact of Ca(ii).

The impact of calcium on the solubility, redox behavior, and speciation of the An(iii)–EDTA (An = Pu or Cm) system under reducing, anoxic conditions was investigated through batch solubility experiments, X-ray absorption spectroscopy (XAS), density functional theory (DFT), and time-resolved laser fluorescence spectroscopy (TRLFS). Batch solubility experiments were conducted from undersaturation using Pu(OH)3(am) as the solid phase in contact with 0.1 M NaCl–NaOH–HCl–EDTA–CaCl2 solutions at [EDTA] = 1 mM, pHm = 7.5–9.5, and [CaCl2] ≤20 mM. Additional samples targeted brine systems represented by 3.5 M CaCl2 and WIPP simulated brine. Solubility data in the absence of calcium were well-described by Pu(iii)–EDTA thermodynamic models, thus supporting the stabilization of Pu(iii)–EDTA complexes in solution. Cm(iii)–EDTA TRLFS data suggested the stepwise hydrolysis of An(iii)-EDTA complexes with increasing pH, and current Pu(iii)-EDTA solubility models were reassessed to evaluate the possibility of including Pu(iii)–OH–EDTA complexes and to calculate preliminary formation constants. Solubility data in the presence of calcium exhibited nearly constant log m(Pu)tot, as limited by total ligand concentration, with increasing [CaCl2]tot, which supports the formation of calcium-stabilized Pu(iii)–EDTA complexes in solution. XAS spectra without calcium showed partial oxidation of Pu(iii) to Pu(iv) in the aqueous phase, while calcium-containing experiments exhibited only Pu(iii), suggesting that Ca–Pu(iii)–EDTA complexes may stabilize Pu(iii) over short timeframes (t ≤45 days). DFT calculations on the Ca–Pu(iii)–EDTA system and TRLFS studies on the analogous Ca–Cm(iii)–EDTA system show that calcium likely stabilizes An(iii)–EDTA complexes but can also potentially stabilize An(iii)–OH–EDTA species in solution. This hints towards the possible existence of four major complex types within Ca–An(iii)–EDTA systems: An(iii)–EDTA, An(iii)–OH–EDTA, Ca–An(iii)–EDTA, and Ca–An(iii)–OH–EDTA. While the exact stoichiometry and degree of ligand protonation within these complexes remain undefined, their formation must be accounted for to properly assess the fate and transport of plutonium under conditions relevant to nuclear waste disposal.

Impact of cardiac amyloidosis on outcomes of patients hospitalized with heart failure in Germany

Abstract Background Amyloidosis is a multi-systemic disease resulting from deposition of misfolded proteins as insoluble fibrils in the interstitium of affected organs including the heart, subsequently leading to organ failure. Cardiac involvement is predominantly observed in light chain (AL) amyloidosis and wild-type transthyretin (ATTRwt) amyloidosis. Purpose We aimed to investigate prevalence and prognostic implications of cardiac amyloidosis of any etiology on outcomes of hospitalized patients with heart failure (HF) in Germany. Methods We analyzed data of the German nationwide inpatient sample (2005–2018) of patients hospitalized for HF (including myocarditis with HF and heart transplantation with HF). HF patients with amyloidosis (defined as cardiac amyloidosis [CA]) were compared with those HF patients without amyloidosis and impact of CA on outcomes was assessed (source: Research Data Center (RDC) of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2005–2018, and own calculations). Results During this fourteen-year observational period 5,478,835 hospitalizations of HF patients were analyzed. Amyloidosis was coded in 5,407 hospitalizations of HF patients (0.1%). Prevalence of CA was 1.87 hospitalizations per 100,000 German population. CA patients were younger (75.0 [IQR 67.0/80.0] vs. 79.0 [72.0–85.0] years, p&amp;lt;0.001), predominantly male (68.9%) and had a higher prevalence of cancer (14.8% vs. 3.6%, P&amp;lt;0.001) compared with HF without amyloidosis. Although patients without amyloidosis had a pronounced cardiovascular risk profile -especially arterial hypertension (45.4% vs. 35.6%; p&amp;lt;0.001) and diabetes mellitus (38.9% vs. 18.5%; p&amp;lt;0.001)- and a higher prevalence of concomitant coronary artery disease (40.5% vs. 34.5%; p&amp;lt;0.001) and chronic obstructive pulmonary disease (17.1% vs. 9.4%; p&amp;lt;0.001), adverse in-hospital events including necessity of transfusions of blood constituents (7.1% vs. 5.4%, p&amp;lt;0.001) and cardio-pulmonary resuscitation (CPR, 2.7% vs. 1.4%; p&amp;lt;0.001) were more frequent in CA. CA was independently associated with acute kidney failure (OR 1.40 [95% CI 1.28–1.52], p&amp;lt;0.001), CPR (OR 1.58 [95% CI 1.34–1.86], p&amp;lt;0.001), intracerebral bleeding (OR 3.13 [95% CI 1.68–5.83], p&amp;lt;0.001) and in-hospital mortality in the 6th and 8th decade of life (6thdecade: OR 1.40 [95% CI 1.01–1.94], p=0.042; 8thdecade: OR 1.18 [95% CI 1.03–1.35], p=0.02). Conclusions CA was identified as an independent risk factor for complications and in-hospital mortality in HF patients. Physicians should be aware of this issue concerning treatments and monitoring of CA-patients. Funding Acknowledgement Type of funding sources: None.

Investigations for Chemical Parameters Effect on Swelling Characteristics of Expansive Soils

A comprehensive understanding of the chemical parameters effect can greatly aid in selecting the most compatible additive and stabilization technique to treat expansive clays. In the present study, influence of chemical parameters (total, leachable and exchangeable forms of sodium and calcium) on swelling (swelling potential, Sa, and swelling pressure, Sp) and consistency properties is quantified by relating them in the form of histograms. It is, in general, noticed that swelling property increases, reaches a peak, and thereafter, decreases with an increase in sodium (Na) and calcium (Ca) content. The value of Ca, Na, and Ca/Na ratio induced maximum swelling to soils are measured in the range of 3–7%, 0.5–0.8%, and 8–11.5 for total, 75–103 mg/kg, 108–164 mg/kg, and 0.7–1.12 for leachable, and 0.8–2.5 and 50–100 meq/100 g, 2–6 meq/100 g, and 0.2–0.5 for exchangeable forms. Three forms including, total, leachable, and exchangeable are found to have a distinct impact on swelling property. The results revealed that Ca/Na ratio, not the individual Ca or Na content, is the better parameter to estimate Sa and Sp of soils. Pertinent to exchangeable form, it is noticed that (a) the range within which Na has pronounced effect on Sa, the impact of Ca in the same range has obscured, (b) Ca/Na ratio, which varied over wider range from 2–120, could be a potential parameter for classifying expansive soils, and (c) exchangeable Ca has no bearing on Sp regardless of its intensity. From the results of the study, it is recommended for expansive clays to accord importance to chemical parameters of the above prescribed limits to design effective foundation systems, avoid swelling induced damage to superstructure, identify the most practicable additive, and select remedial technique to mitigate swelling.

Prognostic impact of CA 19-9 levels in patients with resectable pancreatic cancer who receive adjuvant chemotherapy in randomized controlled trials: A systematic review

Prognostic impact of CA 19-9 levels in patients with resectable pancreatic cancer who receive adjuvant chemotherapy in randomized controlled trials: A systematic review

THE POTENTIAL USE OF Ca(NO3)2 TO IMPROVE SALINITY TOLERANCE IN DATE PALM (Phoenix dactylifera L.)

The study was conducted to investigate the impact of Ca(NO3)2 on different levels of salt-stress in date palm. Three-years-old date palm plants were subjected to four NaCl levels: 50, 100, 150 and 200 mM. The saline solutions were supplemented with 0, 5, 10 and 20 mM Ca(NO3)2. The combined NaCl/Ca(NO3)2 treatments were conducted over a period of 10 weeks. Control plants were only subjected to the four salinity levels with no Ca (NO3)2 addition. Results showed an inhibitory effect of salinity on almost all plants' parameters under investigation, mainly the accumulation of ions such as N, K, Ca, plant dry weight, chlorophyll and net photosynthesis rate. Addition of Ca (NO3)2 in the solution was more beneficial when added in a moderate concentration (10 mM) compared to lower (5 mM) and higher (20 mM) under all salinity levels. The addition of 10 mM Ca (NO3)2 noticeably enhanced chlorophyll content under 50 mM Na Cl (2.5 mg/100 cm2) and 150 mM NaCl (2 mg/100 cm2). In addition, 10 mM Ca (NO3)2 reduced the accumulation of Na and Cl in plant parts. For instance, in trees subjected to 10 mM Ca (NO3)2, Cl content in leaves and stems under 50 mM Na Cl were 0.23% and 0.65%, respectively. On the other hand, Cl content under 100 mM Na Cl and 200 mM Na Cl were lower compared to their corresponding control treatments. It seems that the use of Ca (NO3)2 had ameliorative effects on salt-stressed date palm plants when used with moderate concentrations.

Impact of Ca(II) on the aqueous speciation, redox behavior, and environmental mobility of Pu(IV) in the presence of EDTA

The impact of calcium on the solubility and redox behavior of the Pu(IV)-EDTA system was investigated using a combination of undersaturation solubility studies and advanced spectroscopic techniques. Batch solubility experiments were conducted in 0.1 M NaCl-NaOH-HCl-EDTA-CaCl2 solutions at constant [EDTA] = 1∙10−3 M, 1 ≤ pHm ≤ 11, and 1∙10−3 M ≤ [CaCl2] ≤ 2∙10−2 M. Additional samples targeted brine systems represented by 3.5 M CaCl2 and WIPP simulated brine. Redox conditions were buffered with hydroquinone (pe + pH ≈ 9.5) with selected samples prepared in the absence of any redox buffer. All experiments were performed at T = 22 °C under Ar atmosphere. In-situ X-ray absorption spectroscopy indicated that PuO2(ncr,hyd) was the solubility-controlling phase during the lifetime of all experiments and that aqueous plutonium was present in the +IV oxidation state across all experimental conditions except at pHm ≈ 1, where a small fraction of Pu(III) was also identified. Current thermodynamic models overestimate Pu(IV)-EDTA solubility in the absence of calcium by approximately 1–1.5 log10-units and do not describe the nearly pH-independent, increased solubility observed with increased calcium concentrations. The ternary Pu(IV)-OH-EDTA system without calcium was reevaluated using solubility data obtained in this work and reported in the literature. An updated thermodynamic model including the complexes Pu(OH)(EDTA)−, Pu(OH)2(EDTA)2−, and Pu(OH)3(EDTA)3− was derived. Solubility data collected in the presence of calcium follows a pH-independent trend (log m(Pu)tot vs. pHm), which can only be explained by assuming the formation of a quaternary complex, tentatively defined as CaPu(OH)4(EDTA)2−, in solution. The significant enhancement of plutonium solubility observed in the investigated brine systems supports the formation of a quaternary complex that is not outcompeted by Ca(EDTA)2−, even in concentrated CaCl2 solutions. Although the exact stoichiometry of the complex may need to be revisited, this new quaternary complex has a pronounced impact on plutonium predominance diagrams over a broad range of pH, pe, and calcium concentrations that are relevant to nuclear waste disposal.

Conceptualizing Conduction as a Pliant Vasomotor response: Impact of Ca2+ fluxes and Ca2+ Sensitization.

Coordinating blood flow to active tissue requires vasomotor responses to conduct among resistance arteries. Vasomotor spread is governed by the electrical and mechanical properties of vessels; the latter being linked to the sigmoid relations between membrane potential (VM), [Ca2+], and smooth muscle contractility. Proteins guiding electrical-to-tone translation are subject to regulation; thus, vasomotor conduction could be viewed as "pliant" to the current regulatory state. Using simple in silico approaches, we explored vasomotor pliancy and how the regulation of contractility impacts conduction along a skeletal muscle artery and a branching cerebrovascular network. Initial simulations revealed how limited electromechanical linearity affects the translation of electrical spread into arterial tone. Subtle changes to the VM-[Ca2+] or [Ca2+]-diameter relationship, akin to regulatory alterations in Ca2+ influx and Ca2+ sensitivity, modified the distance and amplitude of the conducted vasomotor response. Simultaneous changes to both relationships, consistent with agonist stimulation, augmented conduction although the effect varied with stimulus strength and polarity (depolarization vs hyperpolarization). Final simulations using our cerebrovascular network revealed how localized changes to the VM-[Ca2+] or [Ca2+]-diameter relationships could regionally shape conduction without interfering with the electrical spread. We conclude that regulatory changes to key effector proteins (e.g. L-type Ca2+ channels, myosin light chain phosphatase), integral to voltage translation, not only impact conducted vasomotor tone but likely blood flow delivery to active tissues.

Impairment of carbonic anhydrase IX ectodomain cleavage reinforces tumorigenic and metastatic phenotype of cancer cells

BackgroundCarbonic anhydrase IX (CA IX) is a hypoxia-induced enzyme regulating tumour pH and facilitating cell migration/invasion. It is primarily expressed as a transmembrane cell-surface protein, but its ectodomain can be shed by ADAM17 to extracellular space. This study aims to elucidate the impact of CA IX shedding on cancer cells.MethodsWe generated a non-shed CA IX mutant by deletion of amino acids 393–402 from the stalk region and studied its phenotypic effects compared to full-length, shedding-competent CA IX using a range of assays based on immunodetection, confocal microscopy, in vitro real-time cell monitoring and in vivo tumour cell inoculation using xenografted NMRI and C57BL/6J female mice.ResultsWe demonstrated that the impairment of shedding does not alter the ability of CA IX to bind ADAM17, internalise, form oligomers and regulate pH, but induces cancer-promoting changes in extracellular proteome. Moreover, it affects intrinsic properties of cells expressing the non-shed variant, in terms of their increased ability to migrate, generate primary tumours and form metastatic lesions in lungs.ConclusionsOur results show that the ectodomain shedding controls pro-tumorigenic and pro-metastatic roles of the cell-associated CA IX and suggest that this phenomenon should be considered when developing CA IX-targeted therapeutic strategies.

Impact of Ca2+ and Mg2+ on the Removal of F− by Magnesium Potassium Phosphate

AbstractThis study investigates the influence of Ca2+ and Mg2+ on the removal of F− by magnesium potassium phosphate (MPP) from water. The kinetic experiments reveal that the F− concentration decreased from 3.5 to 3.31 mg L−1 in a single (F−) system and to 1.45 mg L−1 in a ternary system (F−, Ca2+, and Mg2+) after 1 min, respectively. Thus, the F− removal efficiencies are found to increase by about 53% with the co‐active effect of Ca2+ and Mg2+ in the solution. Moreover, Ca2+ and Mg2+ are almost completely removed in the F−, Ca2+, and Mg2+ system. According to the pseudo‐first‐order modeling, the rate constants k for F−, Ca2+, and Mg2+ are 0.00348, 0.0106, and 0.0159 min−1 respectively; thus, Mg2+ &gt; Ca2+ &gt; F−. In the ternary system, the removal efficiencies are 53.29–66.03% for F−, 99.99–100% for Ca2+, and 87.21–95.19% for Mg2+ with initial pH 5–10. The removal efficiencies of F− increases with increases in initial concentrations of F−, Ca2+, and Mg2+. The removal of F− is governed by two routes: 1) adsorption by electrostatic interactions and outer sphere surface complexation; 2) co‐precipitation with Ca3(PO4)2, CaHPO4, Mg3(PO4)2, and Mg(OH)2.

Electronic Structure of Single-Crystal CaF&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;(111) with Nanoscale Phases of Ca and Si

The impact of Ca and Si nano-scale structures on parameters and density of states of single-crystalline CaF2(111) was studied. It was shown that at low concentration of ions of Ar+ (D ≤ 5 × 1015 cm-2) one witnesses formation of nanoscale phases on CaF2 surface. It was revealed that these phases lead to narrowing of the forbidden band Еg between the phases by 4 - 4.5 eV. At higher concentrations (D ≈ 6 × 1016 cm-2) the surface completely is covered by Ca atoms. It was shown that deposition of θ = 10 thick Si single layer on CaF2 surface manifests island picture. The concentration of Ca and Si nano-scale phases on the surface of CaF2 and the band gap of the phases were investigated as a function of (hν) of passing light. Nano-scale phases and nano-scale films of Ca were obtained by using the technique of bombardment with ions of Ar+ of CaF2 surface. Formation of nano-scale phases were accompanied by change in the composition and structure of CaF2 zones located between the phases. These changes led to narrowing of the forbidden band of CaF2 down to 7.5 - 8 eV. The concentration of Ca and Si nano-scale phases on the surface of CaF2 and the band gap of the phases were investigated as a function of (hν) of passing light.