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In this study, the effect of zirconium addition (1, 1.5, 2 wt%) on the microstructural morphology and wear behavior of Al-Si-Cu-Ni-Mg alloys, known as light metals in which intermediate phases solidify rapidly at high temperatures, was investigated. The study aimed to obtain a stronger material by modifying the Al81Si12Cu4Ni2Mg alloy. It was observed that the Zr added to the alloy was homogeneously distributed throughout the samples. Aluminum and silicon formed compounds with zirconium (Al3Zr and ZrSi2), leading to the formation of a thinner and stronger structure. With the heat treatment applied to the aluminum alloys, the structure became more ductile. Additionally, as a result of Zr addition, microhardness increased, and wear values improved. [ABSTRACT FROM AUTHOR]

Nano Si3N4 powder was successfully synthesized using a combination of sol foaming and carbothermal reduction and nitridation techniques. The process utilized fumed silica (amorphous nano SiO2 powder) as the silicon source, sucrose (C12H22O11) as the carbon source, ammonium chloride (NH4Cl) as the foaming agent, and nitric acid (HNO3) as the oxidant, to prepare precursor of the Si3N4 powder. The objective of this research was to investigate the influence of various factors on the size of the Si3N4 particles. Specifically, the molar ratio of NH4Cl to SiO2 (ε), the foaming temperature, the sintering temperature, and the holding time were analyzed in detail. The results revealed that under the optimized conditions of ε = 1, a SiO2 : C12H22O11 = 1 : 1.5, and a foaming temperature of 350 °C, a fluffy precursor was obtained. This precursor featured amorphous SiO2 evenly coated with organic carbon, which was crucial for the subsequent synthesis process. Subsequently, the precursor was subjected to a nitridation process at 1500 °C for 2 h. This resulted in the formation of nano α-Si3N4 powder. The powder displayed a specific surface area of about 52 m2/g, an average particle size of approximately 20 nm, and a high degree of sphericity. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the in vitro influence of prior silane application on the microshear bond strength (μSBS) of Scotchbond Universal Plus to glass ceramic. Materials and Methods: Thirty blocks of lithium disilicate ceramic were etched with hydrofluoric acid for 20 s and distributed into Group 1 (no silane and no adhesive), Group 2 (adhesive), Group 3 (silane + adhesive). Three cylinders of resin cement were made on each ceramic block. Five blocks (n = 15 cylinders) were subjected to the μSBS test after 24 h, and the other five blocks (n = 15 cylinders) were tested after 6 months of water storage. Results: According to two‐way ANOVA, followed by Tukey's test, the means of μSBS (MPa), denoted by different letters, show significant differences (p < 0.05): after 24 h—Group 1 (31.7)B, Group 2 (43.3)A, and Group 3 (31.3)B; after 6 months—Group 1 (14.8)B, Group 2 (33.6)A, and Group 3 (30.3)A. After 6 months of storage, there was a significant decrease in μSBS for Groups 1 and 2, along with an increase in adhesive failures across all groups. Conclusions: Prior application of silane did not increase the μSBS between Scotchbond Universal Plus and ceramic, and there was degradation at the bond interface over time. Clinical Significance: Prior application of a silane agent is not necessary when using Scotchbond Universal Plus for bonding to glass ceramics. Regardless of the prior application of silane, there is degradation at the bond interface over time. [ABSTRACT FROM AUTHOR]

To develop more sustainable purification and recovery processes, it is critical to accurately determine inorganic impurities of natural graphite (NG) and valuable elements present in low concentrations in steelmaking slag. This study applied three microwave-assisted acid digestion methods for basic oxygen furnace (BOF) slag, NG, and NG ash. Nitric acid (HNO3), hydrochloric acid (HCl), and hydrogen fluoride (HF) were used in method 1. In method 2, method 1 was followed by microwave-assisted boric acid (H3BO3) digestion. In method 3, acids (HNO3, HCl, HF, and H3BO3) were added simultaneously. Concentrations were measured using inductively coupled plasma–optical emission spectrometry. Analytical performance was evaluated using spiking recovery tests (NG) and certified reference (slag) material (CRM). Spiking recoveries for Al, Ca, Fe, K, Mg, Na, and Si were between 5% and 116% (method 1) and 94%–116% (methods 2 and 3). CRM recoveries for Al, Ca, Fe, Mg, Mn, P, Si, Ti, and V were between 2% and 102% (method 1) and 92%–103% (methods 2 and 3). The unsuitability of method 1 was evident due to the low recoveries. Methods 2 and 3 digested Ca- and Si-containing BOF slag completely without visible residue. The sufficient recoveries verified the adequacy of the methods. The suitability of method 3 probably depended on the phases of samples, as quartz was not completely digested from the NG. Method 2 completely digested the inorganic material of NG, and the spiking test showed no loss of volatile silicon compounds. These methods have not been published for NG or NG ash and validated for slag before. [ABSTRACT FROM AUTHOR]

Active gate driving (AGD) is a promising concept for achieving high‐performance power transistor switching. This is particularly crucial for Silicon Carbide (SiC) MOSFETs since their inherently fast switching characteristics give rise to severe overshoots and oscillations which translate into increased levels of electromagnetic interference (EMI) emissions. In this paper, an AGD strategy using a single‐pulse applied during the switching transient is considered for a 1200 V 400 A SiC MOSFET module. The effect of single‐pulse timing, load current, and temperature on the switching performance is analyzed in detail. The radiated EMI reduction benefits are quantified by H‐field and E‐field probes. A conceptual closed‐loop AGD approach is presented and compared to open‐loop operation. For the transistor turn‐off case under full load current of 400 A, experimental results show that it is possible to reduce voltage overshoot by 43.3%, voltage and current oscillations by 69.7% and 52.2% respectively, and EMI by 76.6%, with a trade‐off in the switching energy by a relatively minor increase of 18.2%, compared to the conventional gate driving case. For the turn‐on case, current overshoot was reduced by 32.7%, EMI by 52%, voltage and current oscillations by 54.6% and 52.8%, respectively, with a penalty of 50.9% increase in the switching loss. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, novel chlorine‐thymol derivatives (1,3‐bis(4‐chloro‐2‐isopropyl‐5 methylphenoxy)propan‐2‐ol (Thy‐OHI) and 2‐[2‐(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)ethoxy]ethanol (Thy‐OHII)) and axially di‐4‐chloro‐2‐isopropyl‐5‐methylphenoxy (Thy‐SiPc), 1,3‐bis(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)propanoxy (Thy‐OHI‐SiPc), and 2‐[2‐(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)ethoxy]ethanoxy (Thy‐OHII‐SiPc) substituted silicon phthalocyanine compounds were obtained, and their structures were elucidated by the combination of various methods such as NMR, IR, UV–Vis, and MS. The inhibitory effects of these compounds (Thy‐OHI, Thy‐OHII, Thy‐SiPc, Thy‐OHI‐SiPc and Thy‐OHII‐SiPc), synthesized for the first time, on cholinesterase enzymes (AChE and BChE) were investigated in the laboratory environment. In the studies, notably Thy‐OHI‐Si and thymol derivative ligand Thy‐OHII displayed significant inhibition against AChE and BChE. [ABSTRACT FROM AUTHOR]

This review provides a summary of the existing literature on a crucial raw material for the production of isotopically pure semiconductors, which are essential for the development of second-generation quantum systems. Silicon-28-tetrafluoride (28SiF4) is used as an educt for several isotope-engineered chemicals, such as silane-28 (28SiH4) and silicon-28-trichloride (28SiHCl3), which are needed in the pursuit of various quantum technologies. We are exploring the entire chain from the synthesis of 28SiF4 to quantum applications. This includes the chemical properties of SiF4, isotopic enrichment, conversion to silanes, conversion to bulk 28Si and thin films, the physical properties of 28Si (spin neutrality, thermal conductivity, optical properties), and the applications in quantum computing, photonics, and quantum sensing techniques. [ABSTRACT FROM AUTHOR]

Past one decade has witnessed a tremendous growth in the field of carbene stabilized low‐valent silicon compounds unravelling very exciting properties of these molecules. Herein, we have employed a bicyclic (alkyl)(amino)carbene, (MeBICAAC) to explore the low‐valent chemistry of silicon. The reduction of bicyclic (alkyl)(amino)carbene‐SiCl4 complex, [(MeBICAAC)SiCl4] (1) with KC8 afforded low‐valent Si complexes, including Si(III) radical [(MeBICAAC)SiCl3] (2) and a complex with silicon center in a formal zero‐valent state, [(MeBICAAC)2Si] (3). Similarly, the reduction of in‐situ generated MeBICAAC adduct of Me2SiCl2 with one equivalent of KC8 led to the formation of [(MeBICAAC)SiMe2Cl] (4) complex having an unpaired electron. These complexes have been characterized by IR, UV‐Vis., NMR, HRMS, EPR and their solid‐state structures were also elucidated by single crystal X‐ray crystallography. Further, DFT calculations revealed the lower energy singlet state for complexes 1, 3 and doublet state for complexes 2, 4. [ABSTRACT FROM AUTHOR]

A chiral shape‐persistent macrocyclic compound (Si‐[3]), designed by the C/Si substitution in the spiro‐atom of spirobifluorene in the cyclic trimer (C‐[3]), has been successfully synthesized in this study. The C/Si substitution made the spiro‐conjugation and energy levels of HOMO and LUMO decrease. Due to the silicon substitution, the macrocyclic compound Si‐[3] was able to be degraded by fluoride ions, but its reaction rate was slower than that of the unsubstituted spirosilabifluorene, showing the chemical stability of Si‐[3]. Furthermore, the chiroptical properties of Si‐[3] with D3‐symmetric macrocyclic structure were investigated, and (P,P,P)‐Si‐[3] showed a high emission quantum yield (Φf=80 %) and moderate dissymmetry factor of circularly polarized luminescence (CPL) (glum,exp=−1.2×10−3). According to the time‐dependent density‐functional theory (TD‐DFT) calculations using polarizable continuum model (PCM), the bright CPL from Si‐[3] was explained by a planarization of one bisilafluorenyl moiety at the excited state, which is responsible for the almost fully‐allowed radiative transition with a short emission lifetime of τf=1.89 ns. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm. It highlights various papers that have been published in the journal, covering topics such as the study of defects in crystals, heterojunctions for enhanced photocatalytic activity, reduction of oxygen concentration in silicon crystal growth, structural diversity of substituted thiacalixarene, synthesis of composite anode materials for Li-ion batteries, synthesis and characterization of alkali-metal isocyanurate, tunable emission properties of supramolecular compounds, analysis of crystal packing interactions, and the role of substituents on the molecular and electronic structures of dinuclear complexes. The journal is published by the Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Tunnel boring machines (TBMs) are used to excavate tunnels in a manner where the rock is constantly penetrated with rotating cutter heads. Fine particles of the rock minerals are thereby generated. Workers on and in the vicinity of the TBM are exposed to particulate matter (PM) consisting of bedrock minerals including α-quartz. Exposure to respirable α-quartz remains a concern because of the respiratory diseases associated with this exposure. The particle size distribution of PM and α-quartz is of special importance because of its influence on adverse health effects, monitoring and control strategies as well as accurate quantification of α-quartz concentrations. The major aim of our study was therefore to investigate the particle size distribution of airborne PM and α-quartz generated during tunnel excavation using TBMs in an area dominated by gneiss, a metamorphic type of rock. Sioutas cascade impactors were used to collect personal samples on 3 separate days. The impactor fractionates the dust in 5 size fractions, from 10 µm down to below 0.25 µm. The filters were weighted, and the α-quartz concentrations were quantified using X-ray diffraction (XRD) analysis and the NIOSH 7500 method on the 5 size fractions. Other minerals were determined using Rietveld refinement XRD analysis. The size and elemental composition of individual particles were investigated by scanning electron microscopy. The majority of PM mass was collected on the first 3 stages (aerodynamic diameter = 10 to 0.5 µm) of the Sioutas cascade impactor. No observable differences were found for the size distribution of the collected PM and α-quartz for the 3 sampling days nor the various work tasks. However, the α-quartz proportion varied for the 3 sampling days demonstrating a dependence on geology. The collected α-quartz consisted of more particles with sizes below 1 µm than the calibration material, which most likely affected the accuracy of the measured respirable α-quartz concentrations. This potential systematic error is important to keep in mind when analyzing α-quartz from occupational samples. Knowledge of the particle size distribution is also important for control measures, which should target particle sizes that efficiently capture the respirable α-quartz concentration. [ABSTRACT FROM AUTHOR]

Three dimensional Not-And (3D NAND) flash memory devices are scaling in the vertical direction to more than 200 oxide/sacrificial wordline nitride layers to further increase storage capacity and enhance energy efficiency. The accurate measurement of the thicknesses of these layers is critical to controlling stress-induced wafer warping and pattern distortion. While traditional optical metrology in the UV-vis-NIR range offers a non-destructive inline solution for high volume manufacturing, we demonstrate in this paper, that mid-IR metrology has advantages in de-correlating oxide and nitride thicknesses owing to their unique absorption signatures. Furthermore, because of the depths sensitivity of oxide and nitride absorptions, the simulated measurement results show the ability to differentiate thickness variations in the vertical zones. Good blind test results were obtained with a machine learning model trained on pseudo-references and pseudo spectra with added skew. [ABSTRACT FROM AUTHOR]

Abstract Active gate driving (AGD) is a promising concept for achieving high‐performance power transistor switching. This is particularly crucial for Silicon Carbide (SiC) MOSFETs since their inherently fast switching characteristics give rise to severe overshoots and oscillations which translate into increased levels of electromagnetic interference (EMI) emissions. In this paper, an AGD strategy using a single‐pulse applied during the switching transient is considered for a 1200 V 400 A SiC MOSFET module. The effect of single‐pulse timing, load current, and temperature on the switching performance is analyzed in detail. The radiated EMI reduction benefits are quantified by H‐field and E‐field probes. A conceptual closed‐loop AGD approach is presented and compared to open‐loop operation. For the transistor turn‐off case under full load current of 400 A, experimental results show that it is possible to reduce voltage overshoot by 43.3%, voltage and current oscillations by 69.7% and 52.2% respectively, and EMI by 76.6%, with a trade‐off in the switching energy by a relatively minor increase of 18.2%, compared to the conventional gate driving case. For the turn‐on case, current overshoot was reduced by 32.7%, EMI by 52%, voltage and current oscillations by 54.6% and 52.8%, respectively, with a penalty of 50.9% increase in the switching loss.

Cryogenic etching of a-Si, SiO2, and Si3N4 materials by CHF3/Ar inductively coupled plasma is investigated in a range of temperature from −140 to +20 °C. Samples of the three different materials are placed together on the same silicon carrier wafer. Depending on the experimental conditions, etching or deposition regimes were obtained on the samples. The thickness variation was measured by spectroscopic ellipsometry. A process window between −120 and −80 °C was found in which the Si3N4 surface is etched while CFx deposition is obtained on a-Si and SiO2 surfaces, resulting in the infinite etching selectivity of Si3N4 to the other materials. At high enough self-bias (−120 V) and very low temperature (<−130 °C), Si3N4 etch is reduced down to a very low value, while a-Si and SiO2 are still being etched, which inverses the selectivity between Si3N4 and the two other materials. EDX analyses of a Si3N4/a-Si/SiO2 layer stack after the same etching process carried out at 20 and −100 °C confirm the presence of carbon and fluorine on a-Si at low temperature, showing the effect of the low temperature to switch from the etching to deposition regime on this material. [ABSTRACT FROM AUTHOR]

Silacycloheptatriene (silepin) species are novel silicon compounds reported in recent years. The interplay between the "closed" silepin and the "open" silylene form enables an enhanced stability of the low valent species while maintaining a high reactivity towards small molecules. In this work, two new silepins of similar structures to literature known compounds bearing modified silyl ligands are reported. A unique intramolecular activation of an aromatic hydrogen is found, and the respective formed hydrosilanes are characterized. We further synthesized iron(0) carbonyl complexes of known and new silepins in order to investigate their electronic properties relative to each other to gain more insight into substitution effect in such compounds. [ABSTRACT FROM AUTHOR]

Silicon compounds containing silicon–silicon bond with a variety of unusual oxidation states are quite important, because their high reactivity leads to the formation of a variety of silicon compounds. The isolation of such compounds with unusual oxidation states requires a resilient synthetic strategy. Herein, we report the synthesis of a silicon based spirocyclic compound containing a hyper-valent silicon atom and a silicon–silicon bond. The computational calculations employing natural bond orbital (NBO) analysis and energy decomposition analysis–natural orbitals for chemical valence (EDA–NOCV) reveal that the nature of bonding between the silicon atoms is of an electron sharing nature. [ABSTRACT FROM AUTHOR]

The structural and magnetic analysis of the YFeSb 1. 2 compound synthesized by the solid-state reaction method was observed. At room temperature, the compound exhibits the ThCr2Si2-type structure with the space group of I 4 ∕ m m. Low-field DC magnetic susceptibility property of the YFeSb 1. 2 compound has been examined. An obvious oscillation of the remanent magnetization, M rem (T) with temperature was observed. The YFeSb 1. 2 compound exhibits large irreversibility at low fields below the coercivity fields due to freezing spins at low temperatures. At higher temperatures, the susceptibility obeys perfectly to modified Curie–Weiss behavior. Each magnetic ion on a microscopic scale and each magnetic cluster on a nanoscale experience reveal a local random anisotropy. [ABSTRACT FROM AUTHOR]

Liquid-filled hard gelatin capsules may have pertinent advantages both for therapeutic effect and extemporaneous preparations of medicines. Alpha lipoic acid is a substance used in medicines and dietary supplements and there is a need for creating an appropriate formulation which would be suitable for each individual patient or consumer. Based on its biopharmaceutical and physical chemical characteristics, eight different capsule formulations were designed and characterized. Silicon dioxide was added to form a semisolid content and prevent leakage. The formulation filled with alpha lipoic acid solution in polyethylene glycol 400 showed the best performance. Although the addition of silicon dioxide to the formulation with polyethylene glycol 400 led to a change in both flow character and viscosity, the release rate did not show a statistically significant decrease (more than 85% of content was released after 5 min testing). Applied technique is a simple and an appropriate approach for compounding and could be used for other substances with similar properties. [ABSTRACT FROM AUTHOR]

Organosilicon compounds play a crucial role as essential building blocks and valuable organic molecules in various materials. They are extensively utilized as synthetic intermediates in chemical synthesis processes. Recent studies have highlighted the multifaceted role of silicon compounds, showcasing their significance not only as reactive participants or products but also as potent catalysts in various chemical reactions, as reported by researchers. In this comprehensive review, our objective is to provide a summary of recent advancements in synthesizing various organosilicon compounds in formation of silicon–carbon, silicon–oxygen, silicon–nitrogen and explore the applications of siliconic materials as catalysts in polymerization, reduction, and isomerization processes. Emphasizing the significant potential of this methodology, we aspire to inspire further research and applications in this rapidly emerging field. Furthermore, this review covers over 50 years of research on organosilicon chemistry in CCERCI under supervision of Prof. Seyed Mohammad Bolourtchian. [ABSTRACT FROM AUTHOR]

Phosphoric acid-based geopolymer (PGEO) belongs to acidic material and has many applications in environmental disposal. The curing method has an important impact on the mechanic performance of geopolymers, the existing research concerning PGEO synthesized from fly ash (FA) and phosphoric acid (PA) are performed on the specimens cured at sealed environment, but no related research on the PGEO cured at an open environment is found. Therefore, to investigate the mechanic performance, pH and of PGEO cured in an open environment, the unconfined compressive strength tests were conducted on PGEO specimens cured in an open environment, and its mechanism was investigated using Scanning Electron Microscope, X-Ray diffraction, and Fourier transform infrared reflection (FTIR) tests. Moreover, the thermogravimetric was measured using the thermogravimetric tests. The results showed that in the scope of this study, the compressive strength of the PGEO decreased with the PA concentration and the liquid–solid ratio (L/S) increasing. When the L/S was a fixed value, as the curing time increased, an obvious strength loss was observed for the PGEO with the content of 40 and 50%, but the compressive strength increased first and then, reduced for the PGEO with the content of 40 and 50%, a maximum strength was obtained at 60 days of curing. The open curing for the PGEO is not conducive to the later growth of compressive strength. As the PA concentration and L/S increased, the pH descended. As the curing time lengthened, the pH first raised and then droped, the maximum pH was obtained at 60 days. Furthermore, the compressive strength increased with the pH with a good correlation. The microscopic analysis showed that the crystalline compounds AlSiP3, Ca2P2O7(H2O)2, molecular sieve SAPO-20 (Al0.47Si0.13P0.4)O2, AlPO4-5 (AlPO4), CaHPO4, and AlPO4 in PGEO were detected. Overall, the open curing environment is not conducive to PGEO, and sealed curing should be used in engineering applications. [ABSTRACT FROM AUTHOR]

Silicon included in a restructured meat (RM) matrix (Si-RM) as a functional ingredient has been demonstrated to be a potential bioactive antidiabetic compound. However, the jejunal and hepatic molecular mechanisms by which Si-RM exerts its cholesterol-lowering effects remain unclear. Male Wistar rats fed an RM included in a high-saturated-fat high-cholesterol diet (HSFHCD) combined with a low dose of streptozotocin plus nicotinamide injection were used as late-stage type 2 diabetes mellitus (T2DM) model. Si-RM was included into the HSFHCD as a functional food. An early-stage TD2M group fed a high-saturated-fat diet (HSFD) was taken as reference. Si-RM inhibited the hepatic and intestinal microsomal triglyceride transfer protein (MTP) reducing the apoB-containing lipoprotein assembly and cholesterol absorption. Upregulation of liver X receptor (LXRα/β) by Si-RM turned in a higher low-density lipoprotein receptor (LDLr) and ATP-binding cassette transporters (ABCG5/8, ABCA1) promoting jejunal cholesterol efflux and transintestinal cholesterol excretion (TICE), and facilitating partially reverse cholesterol transport (RCT). Si-RM decreased the jejunal absorptive area and improved mucosal barrier integrity. Consequently, plasma triglycerides and cholesterol levels decreased, as well as the formation of atherogenic lipoprotein particles. Si-RM mitigated the dyslipidemia associated with late-stage T2DM by Improving cholesterol homeostasis. Silicon could be used as an effective nutritional approach in diabetic dyslipidemia management. [ABSTRACT FROM AUTHOR]

This article explores the use of dihydroaromatic compounds as hydrogen donors in transfer hydrogenation reactions. The authors investigate the effectiveness of different Lewis acid catalysts, including silicon-, boron-, and indium-based catalysts, as well as Fe, Co, and Ni halides. They also examine the use of chiral hydride sources for asymmetric transfer hydrogenation. The study finds that FeBr3 is a highly reactive and cost-effective catalyst for transfer hydrogenation reactions, producing moderate to excellent yields of desired products. The catalyst is effective for a range of alkenes, including tetrasubstituted alkenes. Mechanistic studies are conducted to understand the reaction pathway. [Extracted from the article]

This article explores the stabilization of carbenium ions and their role in bond reorganizations, with a specific focus on the β-silicon effect. It discusses the generation of cyclopropyl-stabilized silylium ions and their reactivity in bond reorganization processes, including various rearrangements involving vinylcyclopropanes. The article provides insights into the mechanisms and outcomes of these reactions and discusses their potential applications in the synthesis of silicon-containing compounds. The authors also investigate different variations of substituents and nucleophilic coupling partners, highlighting the importance of careful reaction conditions in obtaining specific products. [Extracted from the article]

It is not yet clear how adding silicon foliar fertilisation affects olive leaf (OL) phenolics and their potential to impact different cancer cells. Thus, we conducted a field trial to study the effect of foliar Si biostimulant fertilisation on the OL phenolic content of the 'Leccino' (LE) and 'Istarska Bjelica' (IB) cultivars. The experiment compared untreated Control (C) and three distinct levels of silicon (Si1, Si2, Si3) with Si concentrations of 0.55 g/L, 1.1 g/L, and 2.2 g/L, respectively. Si3 application resulted in the highest levels of oleuropein, apigenin-7-O-glucoside, luteolin-4-O-glucoside, rutin, and tyrosol compared to the C treatment. The polyphenols showed high cytotoxic activity in three cancer cell lines tested: cervical adenocarcinoma (HeLa), colon cancer (HCT116), and osteosarcoma (U2OS). The strongest inhibition of cell growth was observed in the HCT116 cell line. All cancer cells tested were more sensitive to treatment with polyphenols isolated from plants with added Si than those without added Si. The cytotoxic activity of the extracts on the healthy cell line RPE1 was similar to that on the cancer cell line HCT116 and U2OS. [ABSTRACT FROM AUTHOR]

An improved sessile drop method was used to measure the dynamic nonreactive wetting behavior of different titanium concentrations interstitial-free molten steel on an alumina substrate at 1550 ºC, and the interfacial tension was also calculated by Young' equation based on the measured surface tension and the static contact angle compared to the previous sessile drop method. And the discrepancies were investigated by analyzing the interface layer between the melt and the alumina substrate with different oxygen partial pressures. Furthermore, it was discussed for the forces analysis of the dynamic contact angle for the improved sessile drop method and the interface layer reactive for the improved sessile drop method. The results demonstrate that the advancing angle, receding and static contact angles between the flowing melt and the solid substrate were quickly obtained by the improved sessile drop method. And the interfacial tension between molten steel and alumina substrate, which is 1428.71 and 1221.35 mN/m, respectively, with titanium concentrations of 280 ppm and 540 ppm for the improved sessile drop method, is higher than for the previous sessile drop method, which is 1245.56 and 719.01 mN/m, respectively. The low alloy interstitial-free molten steel and alumina substrate had formed an interface layer for the previous sessile drop method, and the thickness of the interface layer increased from 3.5 to 77.8 μm with a titanium concentration of 540 ppm as the oxygen partial pressure increased from 5.4 × 10−23 to 5.4 × 10−19 atm. The interface layer, which is composed of alloy compounds such as silicon, manganese and titanium oxides, is sensitive to the active alloy of interstitial-free molten steel and oxygen partial pressure. [ABSTRACT FROM AUTHOR]

Organosilicon compounds are versatile reagents in chemical synthesis and materials sciences. As an important class of organosilanes, 1,1,1-trisilylalkanes can undergo various organic transformations and serve as core units for silicon-containing hyperbranched polymers. The existing catalytic approaches for accessing 1,1,1-trisilylalkanes via alkyne trisilylation not only requires pre-synthesized moisture- and air-sensitive organocalcium and organolanthanum catalysts but also suffers from limited substrate scope for both alkyne and hydrosilane reagents. For example, only alkyl-substituted alkynes can undergo organocalcium-catalyzed trisilylation with alkyl hydrosilanes to provide the desired 1,1,1-trisilylalkane products. Herein, we report a selective copper-catalyzed trisilylation reaction of both alkyl- and aryl-substituted alkynes with a readily accessible copper catalyst that is generated in situ from Cu(OAc)2 and tributylphosphine PnBu3. This copper-catalyzed trisilylation reaction features easy catalyst preparation, broad substrate scope, and mild solvent-free reaction conditions. Mechanistic studies reveal that this trisilylation reaction occurs through copper-catalyzed deprotosilylation of alkynes to form alkynylsilanes followed by double hydrosilylation of alkynylsilane. [ABSTRACT FROM AUTHOR]

Removing impurities that occur in landfill gas, from sulphur and silicon compounds, is crucial for the energetic use of biogas in a cogeneration unit for energy purposes. The aim of this study was to analyse the shaped activated carbon, examining its structure and elemental composition as part of the biogas purification. The qualitative study of the purified landfill gas performed in this study showed a significant overshoot of hydrogen sulphide at 304.1 ppm with respect to the gas engine manufacturer's requirements, while the calculated hydrogen sulphide reduction efficiency was 24.58%. Examination of the surface of the spent carbon and its pores with a scanning microscope revealed a high level of clotting by sulphur compounds, which prevents proper reduction of this compound and reduces the efficiency of the treatment plant. Replacement of the activated carbon bed with a new one showed a hydrogen sulphide value of 7.5 ppm in the purified gas and a calculated reduction efficiency of 97.9%. The results of the study confirmed that continuous monitoring of the quality of the purified gas is necessary to control the adsorption properties of the activated carbon and can be used for the operation of gas engines in cogeneration units. The landfill gas treatment method described in this paper constitutes an environmentally sustainable project within the meaning of the EU regulation on the establishment of a framework to promote and facilitate this type of investment in terms of its financing and operation. The topic of the work fits into three key areas of broad research and implementation activities. The first, technological, is the transition to a low-carbon, sustainable and resource-efficient closed-loop economy; the second, environmental, pollution prevention and control. The third area is economics and finance in terms of making financial products available designed to reduce climate change and reporting on these activities. [ABSTRACT FROM AUTHOR]

Silicon nitride (Si3N4) ceramics using four compound sintering aids Er2O3–MgO, Er2O3–MgF3, Er2O3–Mg2Si, and Er2O3–Mg3N2. The effects of binary sintering aid types and temperatures on the microstructure, mechanical properties, and thermal conductivity of Si3N4 ceramics were investigated. The depolymerization effect of fluorine atoms introduced by MgF2 sintering additives on the silicate melt structure reduced the viscosity of the liquid phase. However, the existence of volatile phase leads to low density of Si3N4 ceramics. While the additional Si and N atoms increase the concentration of solute atoms, which was conducive to sintering densification of Si3N4 ceramics. Although Mg2Si and Mg3N2 sintering aids produced higher viscosity liquid phase compared with MgF2, denser Si3N4 ceramics were obtained at 1900°C. The Si3N4 ceramics doped with 5 mol% Er2O3 and 2 mol% Mg3N2 at 1900°C showed the excellent properties: including the highest Vickers hardness (16.8 GPa), flexural strength (912 MPa), and fracture toughness (8.1 MPa m1/2), as well as the desirable thermal conductivity (83 W/(m K)). [ABSTRACT FROM AUTHOR]

With the advent of the highly developed era of 5G, AI, and IoT, the latest generation of ICs is designed with smaller-sized FETs, lower time delays, and reduced power consumption. To address the challenges posed by these advancements, materials with a lower k value than silicon dioxide (low-k, <4.0) are being developed to reduce resistance-capacitance (RC) time delays and power consumption. While low-k materials are still emerging, various material companies continue to introduce innovative low-k products, such as SiLK, Fox, Coral, and Aurora from different companies. Simultaneously, considering proprietary business interests, the processes and materials associated with these products have not been clearly presented. In this report, we employ a novel set of equipment to validate an innovative formulation for synthesizing a low-k silicon dioxide layer. Thickness measurements confirm a higher deposition rate of silicon dioxide layers, with excellent uniformity observed on 8” wafer. Furthermore, the dielectric constant (k) decreases to 2.35, indicating the production of a great low-k material. Additionally, in the formulation of reactants, we avoid the use of silane and organic silane, contributing to improved safety in the facility and effective control of reactant costs. The results highlight an advantageous option for fabricating interconnect layers in ICs. [ABSTRACT FROM AUTHOR]

Semiconductor industry is experiencing a rising demand for environmentally friendly processes with the emphasis on green policies and worldwide environmental sustainability. Nitrogen trifluoride (NF3), the most common plasma chamber cleaning agent gas, poses a significant concern as a potent greenhouse gas since it has global warming potential (GWP), 740 times and 6 times higher than that CO2 and N2O. This study investigated the exhaust gas using quadrupole mass spectroscopy (QMS) and analyzed the change in cleaning speed and the type of exhaust gas through plasma monitoring using optical mass spectroscopy (OES). The objective is to lower the use of the amount of NF3 gas in chamber cleaning process to partially contribute the environmental sustainability in the point of semiconductor manufacturing. When a small amount of N2 was added to NF3 whose ratio of 7:23, the cleaning efficiency reached to 90% compared to NF3 gas alone. Addition of N2 positively affected electron density and temperature to increase the F-radical in remote plasma system. In conclusion, 18% of NF3 usage amount was reduced during the Sio2 deposition chamber cleaning process. [ABSTRACT FROM AUTHOR]

The article presents some existing methods of producing silicon carbide, forms and types of silicon carbide, various compositions and formulations, production technology. The authors proposed a new method of processing silicon production waste - microsilica by spark plasma sintering with a carbon-containing reducing agent (soot) which produces a silicon carbide compound. Studies have shown that sintered silicon carbide has improved strength properties. Thus, the possibility of application of production wastes to create new composite materials characterized by a certain complex of properties is confirmed. [ABSTRACT FROM AUTHOR]

The excessive emission of iron will pollute the environment and harm human health, so the fluorescence detection and adsorption of Fe3+ are of great significance. In the field of water treatment, cellulose-based gels have attracted wide attention due to their excellent properties and environmental friendliness. If carbon dots are used as a crosslinking agent to form a gel with cellulose, it can not only improve mechanical properties but also show good biocompatibility, reactivity, and fluorescence properties. In this study, silicon-doped carbon dots/carboxymethyl cellulose gel (DCG) was successfully prepared by chemically crosslinking biomass-derived silicon-doped carbon dots with carboxymethyl cellulose. The abundant crosslinking points endow the gel with excellent mechanical properties, with a compressive strength reaching 294 kPa. In the experiment on adsorbing Fe3+, the theoretical adsorption capacity reached 125.30 mg/g. The introduction of silicon-doped carbon dots confers the gel with excellent fluorescence properties and a good selective response to Fe3+. It exhibits a good linear relationship within the concentration range of 0–100 mg/L, with a detection limit of 0.6595 mg/L. DCG appears to be a good application prospect in the adsorption and detection of Fe3+. [ABSTRACT FROM AUTHOR]

Current research on materials engineering focuses mainly on bio-based materials. One of the most frequently studied materials in this group is polylactide (PLA), which is a polymer derived from starch. PLA does not have a negative impact on the natural environment and additionally, it possesses properties comparable to those of industrial polymers. The aim of the work was to investigate the potential of organosilicon compounds as modifiers of the mechanical and rheological properties of PLA, as well as to develop a new method for conducting mechanical property tests through innovative high-throughput technologies. Precise dosing methods were utilized to create PLA/silicone polymer blends with varying mass contents, allowing for continuous characterization of the produced blends. To automate bending tests and achieve comprehensive characterization of the blends, a self-created workstation setup has been used. The tensile properties of selected blend compositions were tested, and their ability to withstand dynamic loads was studied. The blends were characterized through various methods, including rheological (MFI), X-ray (XRD), spectroscopic (FTIR), and thermal properties analysis (TG, DSC, HDT), and they were evaluated using microscopic methods (MO, SEM) to examine their structures. [ABSTRACT FROM AUTHOR]

The article discusses the challenges and opportunities presented by the integration of artificial intelligence (AI) and the Internet of Things (IoT), highlighting the potential benefits for various industries such as healthcare, agriculture, and transportation. It discusses how AI-powered IoT devices can enhance efficiency, productivity, and decision-making processes while also addressing concerns about data privacy and security.

Objective: Obtaining strong resin bonds to computer‐aided design and computer‐aided manufacturing (CAD‐CAM) resin‐based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two‐component silane coupling agent on the shear bond strength to three (CCRBCs). Materials and Methods: Eight hundred and sixty‐four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). Results: After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). Conclusions: Bond strength of universal adhesives varied with CCRBC type. The two‐component silane coupling agent showed mixed effects on adhesive performance. Clinical Significance: Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate. [ABSTRACT FROM AUTHOR]

The use of silicon (Si) can minimize the adverse effects of abiotic stresses, increase resistance against arthropod pests, and promote growth in fruit crops. Considering the beneficial effects of Si reported in various crops and the limited information on its effect on avocado, this study investigated the effects of the application of two sources of Si (acidic and alkaline) on the physiology, growth, and population dynamics of arthropod pests of 'Hass' avocado plants. Three experiments were carried out at three different plant development stages: seedlings (Fresno, Tolima), young (Bituima, Cundinamarca), and adult trees (El Tablazo, Tolima). The treatments were as follows:1) plants without Si application (control), 2) plants with foliar application of acidic Si, 3) plants with foliar application of basic Si, and 4) plants with foliar treatment of acidic and basic Si and pyrethrins. Foliar applications of Si caused less accumulation of adult arthropod pests such as Heliothrips haemorrhoidalis, Monalonion velezangeli, Polyphagotarsonemus latus, Bombacoccus aguacatae, Paraleyrodes sp., and Oligonychus yothersi compared to the control treatment. Foliar applications of Si (both sources) also increased plant height and shoot length. Si had a positive effect on leaf stomatal conductance, chlorophyll content, and plant hydraulic conductivity at the end of the three experiments. The results obtained allow us to conclude that the use of Si can be considered a complementary tool in the management of some arthropod pests in avocados. In addition, Si may help in the management of avocado crops by improving the physiological responses of plants at different developmental stages. [ABSTRACT FROM AUTHOR]

The adsorption of the C60 fullerene molecule has been studied in various configurations on a reconstructed Si(100) silicon surface. Among fullerenes, fullerene C60 is of particular importance, since it has the most stable form and consists of 60 carbon atoms. Monocrystalline silicon has the diamond structure, the size of its crystal lattice is 5.43 Å. The MD-simulation calculations have been performed using the open source LAMMPS MD-simulator software package and the Nanotube Modeler computer program. The Tersoff interatomic potential has been used to determine the interactions between the Si-Si, C-C and Si-C atoms. The adsorption energy of the C60 molecule on the reconstructed Si(100) surface, the bond lengths and the number of bonds formed depend on the adsorption geometry, i.e. at what point on the substrate the molecule is adsorbed and in what configuration. [ABSTRACT FROM AUTHOR]

The research of the batteries is still going forward and there are lots of challenges which should be solved. This text examines the effect of external pressure on different types of batteries and explores their potential for improving performance and lifetime. The studies reviewed in the text show interesting results where external pressure affects capacity, internal resistance, stability or other parameters of modern battery systems as Li-ion, solid-state, or Li–S batteries. Despite the challenges, the benefits for next-generation batteries seem promising and show its role in battery development and manufacturing. [ABSTRACT FROM AUTHOR]

Aims and objectives: To analyze anti-MMP mode of action of Quaternary Ammonium Silane (QAS, codenamed as k21) by binding onto specific MMP site using computational molecular simulation and Anti-Sortase A (SrtA) mode of action by binding onto specific site using computational molecular simulation. Materials and methods: In silico Molecular Dynamics (MD) was used to determine the interactions of K21 inside the pocket of the targeted protein (crystal structure of fibroblast collagenase-1 complexed to a diphenyl-ether sulphone based hydroxamic acid; PDB ID: 966C; Crystal structure of MMP-2 active site mutant in complex with APP-derived decapeptide inhibitor. MD simulations were accomplished with the Desmond package in Schrödinger Drug Discovery Suite. Blood samples (~ 0.5 mL) collected into K2EDTA were immediately transferred for further processing using the Litron MicroFlow® PLUS micronucleus analysis kit for mouse blood according to the manufacturer's instructions. Bacterial Reverse Mutation Test of K21 Molecule was performed to evaluate K21 and any possible metabolites for their potential to induce point mutations in amino acid-requiring strains of Escherichia coli (E. coli) (WP2 uvrA (tryptophan-deficient)). Results: Molecular Simulation depicted that K21 has a specific pocket binding on various MMPs and SrtA surfaces producing a classical clouting effect. K21 did not induce micronuclei, which are the result of chromosomal damage or damage to the mitotic apparatus, in the peripheral blood reticulocytes of male and female CD-1 mice when administered by oral gavage up to the maximum recommended dose of 2000 mg/kg. The test item, K21, was not mutagenic to Salmonella typhimurium (S. typhimurium) strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2 uvrA in the absence and presence of metabolic activation when tested up to the limit of cytotoxicity or solubility under the conditions of the test. Conclusion: K21 could serve as a potent protease inhibitor maintaining the physical and biochemical properties of dental structures. [ABSTRACT FROM AUTHOR]

As part of this research, new halogen free organosilicon compounds were synthesized for the modification of natural fabrics. Difunctional polysiloxanes containing alkoxysilyl groups and silsesquioxane moieties in their structure were obtained by hydrosilylation or thiol-ene click reaction. Using two different reactions leading to the formation of polysiloxane derivatives, we demonstrate the influence of the chemical structure of the obtained polymers on the properties of modified cotton. The structure of the synthesized compounds was confirmed by FT-IR and NMR spectroscopy. After the synthesis of 6 different polysiloxane derivatives with different content of functional groups in their structures, they were applied to the natural fabrics in order to render them hydrophobic. The samples were modified via the dip-coating process. As a result of the research, superhydrophobic fabrics were obtained that are completely resistant to the process of repeated washing. The water repellency of the fabrics was assessed by measuring the water contact angle. The presence of the modifier on the fiber surface (before and after washing) was confirmed by FT-IR and SEM–EDS analysis. In addition, the surface of the modified fibers was examined using SEM images. [ABSTRACT FROM AUTHOR]

Low‐valent silicon compounds such as neutral silylenes display versatile reactivity for the activation of small molecules. In contrast, their anionic congeners silanides ([R3Si−]) have primarily been investigated for their nucleophilic reactivity. Here we show that incorporating a silanide center in a bicyclic cage structure allows for formal oxidative addition of polar element‐hydrogen bonds (RX−H, R=aromatic residue, X=O, S, NH). The resulting hydrosilicates were isolated and characterized structurally and spectroscopically. Density Functional Theory (DFT) calculations and experimental observations support an ionic mechanism for RX−H bond activation. Finally, the reactivity of the RS−H bond adduct was further investigated, revealing that it behaves as a Lewis pair upon facile heterolytic cleavage of the Si−S bond. [ABSTRACT FROM AUTHOR]

Pyrometallurgical processes produce slags that may contain valuable elements because of their high oxygen affinity. However, the concentration is extremely low, which causes losses. In fact, these elements, for example, tantalum and rare earth elements, are less than 1% recycled. To return such technologically important elements to the material cycle, pyrometallurgically is used to enrich them in the simplest possible compounds within the slag, which have favorable properties for recovery (morphology, crystal size, magnetic properties), allowing further mechanical separation. The purpose of modification of the slag system is to obtain engineered artificial minerals" (EnAM), a process in which targeted minerals with high element concentration are formed. In this article, this approach is investigated using tantalum-rich fayalitic slag, since this slag is commonly found in the industry for the pyrometallurgical treatment of waste electric and electronic equipment. Synthetic fayalitic slags in reducing environment under different cooling rates were produced with Ta addition. The characterization of the produced samples was carried out using powder X-ray diffraction (PXRD) and electron probe microanalysis (EPMA). Additionally, the speciation of Fe and Ta was accessible through X-ray absorption near-edge structure (XANES) spectroscopy. EPMA also provided a semiquantitative assessment of the Ta distribution in these individual compounds. In these slags, tantalum accumulated in perovskite-like oxidic and silicate compounds as well as in magnetic iron oxides. The enrichment factor is highest in tantalite/perovskite-type oxides (FexTayO6, CaxFeyTazO3) with up to 60 wt.% Ta and 'tantalomagnetite' (FeII(FeIII(2-5/3x)Tax)O4) with a maximum of ~30 wt.% Ta (only fast cooling). This is followed by a perovskite-like silicon containing oxide (XYO3) with 12–15 wt.% Ta (only slow cooling), and a hedenbergite-like compound (XYZ2O6) with a varying content of 0.3–7 wt.%. The Ta concentration in pure Fe, Fe(1-x)O, hercynitic spinel and hematite is negligible. Despite the very low phase fraction, the most promising EnAM compound is nevertheless perovskite-like tantalum oxide, as the highest enrichment factor was obtained. Tantalum-rich magnetite-like oxides also could be promising. [ABSTRACT FROM AUTHOR]

In this work, the bandgap energy of Si samples doped with impurity atoms of elements Ga (AIII) and Sb (BV) by the diffusion method and without impurity atoms was studied. It is known that the bandgap energies of GaSb and Si semiconductors at room temperature are 0.726 and 1.12 eV, respectively. According to the results of the study, it was found that the band gap energies of Ga and Sb-doped and non-doped Si samples are 1.114 and 1.119 eV, respectively. When the samples were further annealed at a temperature of 600 °C, it was observed that the bandgap energy of the samples doped with Ga and Sb decreased to 1.10 eV. [ABSTRACT FROM AUTHOR]

The patterning of silicon and silicon oxide nanocones onto the surfaces of devices introduces interesting phenomena such as anti-reflection and super-transmissivity. While silicon nanocone formation is well-documented, current techniques to fabricate silicon oxide nanocones either involve complex fabrication procedures, non-deterministic placement, or poor uniformity. Here, we introduce a single-mask dry etching procedure for the fabrication of sharp silicon oxide nanocones with smooth sidewalls and deterministic distribution using electron beam lithography. Silicon oxide films deposited using plasma-enhanced chemical vapor deposition are etched using a thin alumina hard mask of selectivity > 88, enabling high aspect ratio nanocones with smooth sidewalls and arbitrary distribution across the target substrate. We further introduce a novel multi-step dry etching technique to achieve ultra-sharp amorphous silicon oxide nanocones with tip diameters of ~10 nm. The processes presented in this work may have applications in the fabrication of amorphous nanocone arrays onto arbitrary substrates or as nanoscale probes. [ABSTRACT FROM AUTHOR]

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Understanding the adsorption interactions between carbon materials and sulfur compounds has far‐reaching impacts, in addition to their well‐known important role in energy storage and conversion, such as lithium‐ion batteries. In this paper, properties of intrinsic B or Si single‐atom doped, and B–Si codoped graphene (GR) and graphdiyne (GDY) were investigated by using density functional theory‐based calculations, in which the optimal doping configurations were explored for potential applications in adsorbing sulfur compounds. Results showed that both B or Si single‐atom doping and B–Si codoping could substantially enhance the electron transport properties of GR and GDY, improving their surface activity. Notably, B and Si atoms displayed synergistic effects for the codoped configurations, where B–Si codoped GR/GDY exhibited much better performance in the adsorption of sulfur‐containing chemicals than single‐atom doped systems. In addition, results demonstrated that, after B–Si codoping, the adsorption energy and charge transfer amounts of GDY with sulfur compounds were much larger than those of GR, indicating that B–Si codoped GDY might be a favorable material for more effectively interacting with sulfur reagents. [ABSTRACT FROM AUTHOR]

Background: This study assessed the effect of different concentrations of 4-methacryloyloxyethy trimellitate anhydride (4-META) added to silane on microtensile bond strength (µTBS) of light-cure and dual-cure resin cement to hybrid and zirconia-reinforced lithium silicate ceramics. Materials and Methods: This in vitro, experimental study was conducted on 32 Celtra Duo and 32 VITA Enamic ceramics bonded to Allcem Veneer light-cure and Allcem dual-cure resin cements using silane impregnated with 4-META in 0%, 2.5%, 5%, and 10 wt% concentrations in 16 groups (n = 4). The µTBS of specimens was measured by a universal testing machine and analyzed by the Kruskal-Wallis and Mann-Whitney tests, and the mode of failure was determined under a stereomicroscope and analyzed by the Chi-square test (alpha = 0.05). Results: The lowest mean µTBS was recorded in the Enamic ceramic group with 4-META (0%) bonded to dual-cure cement (14.26 MPa), and the highest mean µTBS was recorded in Enamic ceramic with 4-META (10%) bonded to light-cure cement (18.59 MPa) (P < 0.001). The µTBS of Celtra Duo was significantly higher than that of Enamic in bonding to light-cure cement using 4-META (2.5%) (P = 0.003). All failures (100%) were adhesive in most groups. The frequency of adhesive failure was the lowest (90%) in Celtra Duo bonded to dual-cure cement with 4-META (5%). Conclusion: According to the results of this pilot study, the addition of 4-META (10%) to silane caused a significant improvement in µTBS to light-cure cement. The addition of 4-META in all concentrations significantly improved the µTBS to Enamic ceramic in the use of dual-cure cement; however, it had no significant effect on µTBS of Celtra Duo. Nonetheless, the results should be interpreted with caution due to the relatively small sample size. [ABSTRACT FROM AUTHOR]