Constituents Of Mixture Research Articles

The Contribution of Endmembers to Mixtures of Leaf Leachates and Riverine DOM can be Determined by Measuring Their Size and Fluorescence Properties

The molecular mass distribution (MMD) and fluorescence properties of dissolved organic matter (DOM) are important characteristics for tracing and predicting its pathways, processes, and fate in aquatic systems. For the first time, asymmetrical flow field-flow fractionation (AF4) with coupled absorbance and fluorescence detectors was used to determine the contribution of endmembers to three mixtures of leaf leachate and riverine DOM in various proportions. Parallel factor analysis (PARAFAC) and fractogram deconvolution were used to decompose and distinguish the size distributions and fluorescence excitation-emission matrices (EEMs) of mixture constituents. It was determined that: 1) Both size and optical properties were conservative tracers in mixtures; 2) Fractogram deconvolution was extremely helpful for discriminating endmember size properties; 3) The contributions of endmembers to overall DOC concentration were accurately estimated using both the proportion of a humic-like PARAFAC component (0.93 < R2 < 1.00), and the ratios of deconvoluted peaks (0.88 < R2 < 0.98). The fluorescence at the peak maximum of the MMD was lacking in protein-/polyphenol-like and microbial humic-like fluorescence compared to the whole sample (−11 ± 9 and −10 ± 7%, respectively); however, the contribution of endmembers to the MMD (A254) were also effectively predicted using both the proportion of a microbial humic-like PARAFAC component (0.91 < R2 < 0.98) and the ratio of deconvoluted peaks (0.94 < R2 < 0.98).

Produced Water Treatment and Valorization: A Techno-Economical Review

In recent years, environmental concerns have urged companies in the energy sector to modify their industrial activities to facilitate greater environmental stewardship. For example, the practice of unconventional oil and gas extraction has drawn the ire of regulators and various environmental groups due to its reliance on millions of barrels of fresh water—which is generally drawn from natural sources and public water supplies—for hydraulic fracturing well stimulation. Additionally, this process generates two substantial waste streams, which are collectively characterized as flowback and produced water. Whereas flowback water is comprised of various chemical additives that are used during hydraulic fracturing; produced water is a complex mixture of microbiota, inorganic and organic constituents derived from the petroliferous strata. This review will discuss the obstacles of managing and treating flowback and produced waters, concentrating on the hardest constituents to remove by current technologies and their effect on the environment if left untreated. Additionally, this work will address the opportunities associated with repurposing produced water for various applications as an alternative to subsurface injection, which has a number of environmental concerns. This review also uses lithium to evaluate the feasibility of extracting valuable metals from produced water using commercially available technologies.

Experimental investigation on SMAW electrode coatings developed using CaO–SiO2–CaF2–SrO based coating system

This research aims to provide a SMAW electrode coating developed using a CaO–SiO2–CaF2–SrO flux system for welding the components of an advanced ultra-supercritical power plant. The physicochemical and thermophysical characteristics of developed coatings were investigated. Twenty-one distinct electrode coating formulations were developed using the extreme vertices technique. Experiments for several thermophysical and physicochemical characteristics were carried out. The coating's qualities are critical for producing a strong weld that will last in the field. X-ray diffraction and Infrared spectroscopy were used to examine the structural behavior of the electrode coatings. Furthermore, the regression model was developed to explore the effect of coating compositions. The primary constituents and their interaction have an influential role in physicochemical and thermophysical characteristics. Individual and ternary mixtures significantly affect the density. CaO.SiO2.SrO and CaF2·SiO2·SrO is the most effective ternary mixture, which has an increasing effect on density. The weight loss of coating observed during thermogravimetric analysis is affected by individual constituents significantly. The ternary mixture CaO·CaF2·SiO2, CaO·CaF2·SrO, and CaF2·SiO2·SrO is the most favorable and has an increasing effect on weight loss. Individual constituents affect change in enthalpy significantly. The thermal properties of coating observed during hot disc are affected by binary and ternary mixture constituents. Binary mixture CaO·SiO2 is having an increasing effect on thermal conductivity. Binary mixture CaO·SrO and SrO containing ternary mixture have an increasing impact on thermal diffusivity. Ternary mixture constituents CaO·CaF2·SrO, CaF2·SiO2·SrO is the most effective and has an increasing effect on specific heat.

Biologically Active Constituents of Natural Medicines -A Mixture Can Do More

Natural medicines, including crude drugs and Kampo prescriptions, have a long history of clinical uses. An important characteristic of natural medicines is that they are multicomponent medicines. Kampo prescriptions, particularly, usually consist of several crude drugs that contain a large number of constituents. The therapeutic effects of a Kampo prescription result from the total effects of its constituents and not from the effect of a representative constituent with a strong pharmacological effect. In fact, only a few of these constituents with strong biological activity have been listed in the Japanese Pharmacopoeia as therapeutic agents. During my research career, I have observed various synergistic effects and interactions among the constituents of natural medicines. This article reviewed our researches on the biologically active constituents of natural medicines, including the analysis of the anti-inflammatory constituents of orengedokuto (a Kampo prescription). Understanding the role of each constituent with therapeutic effects in Kampo prescriptions forms a scientific basis of Kampo medicine. This will enable the better use and quality control of Kampo prescriptions. Moreover, this will aid the future development of a multicomponent mimic for a specific effect of a Kampo prescription using the appropriate mixture of active constituents in amounts found in the prescription. The above is my dream as a natural product chemist, and I believe that the mixture can do more than we anticipate!

Electrically controlling and optically observing the membrane potential of supported lipid bilayers

Supported lipid bilayers are a well-developed model system for the study of membranes and their associated proteins, such as membrane channels, enzymes, and receptors. These versatile model membranes can be made from various components, ranging from simple synthetic phospholipids to complex mixtures of constituents, mimicking the cell membrane with its relevant physiochemical and molecular phenomena. In addition, the high stability of supported lipid bilayers allows for their study via a wide array of experimental probes. In this work, we describe a platform for supported lipid bilayers that is accessible both electrically and optically, and demonstrate direct optical observation of the transmembrane potential of supported lipid bilayers. We show that the polarization of the supported membrane can be electrically controlled and optically probed using voltage-sensitive dyes. Membrane polarization dynamics is understood through electrochemical impedance spectroscopy and the analysis of an equivalent electrical circuit model. In addition, we describe the effect of the conducting electrode layer on the fluorescence of the optical probe through metal-induced energy transfer, and show that while this energy transfer has an adverse effect on the voltage sensitivity of the fluorescent probe, its strong distance dependency allows for axial localization of fluorescent emitters with ultrahigh accuracy. We conclude with a discussion on possible applications of this platform for the study of voltage-dependent membrane proteins and other processes in membrane biology and surface science.

Suppressive effects of composite flame retardant on smoke release, combustion soot and residue constituents of asphalt mixture

Asphalt pavement has been widely applied in the road tunnel. In tunnel fire, the combustion of asphalt pavement produces large quantities of toxic, carcinogenic and harmful black smoke, which causes serious environmental pollution. To explore the inhibition of composite fire retardant (CFR) on combustion soot release of asphalt mixtures for reducing environmental pollution, this paper investigated the combustion soot produced by asphalt mixtures using cone calorimeter (CONE) test. Then the influence of CFR on the composition of combustion residues in asphalt mixture was investigated employing the solid-phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC-MS) technique to reveal the smoke suppression mechanism of each constituent of CFR on the combustion of asphalt mixture. Through the detection and analysis of the combustion soot of asphalt mixture and CFR asphalt mixture, it is found that the main types of alkanes are reduced, and the unsaturated alkenes and alkynes disappear after the addition of CFR. Test results show that the composition of combustion residues of CFR asphalt mixture is significantly reduced compared with that of asphalt mixture. Compared with the combustion soot and residues of CFR asphalt mixture, it is found that the molecular weights of characteristic substances of combustion soot and residues after the burning of asphalt mixture are smaller. Therefore, it is of great significance in the fire safety field to study the influence of newly developed CFR on the combustion soot and combustion residues of asphalt mixture when exposed to fire.

Computation of edge- and vertex-degree-based topological indices for tetrahedral sheets of clay minerals

AbstractIn terms of soil conditions, clay minerals infrequently occur as homogenous mixtures of single constituents, gatherings, stages, or types of minerals. Rather, they contain intricate arrays of essential minerals and rippling intermediates of numerous basic and synergistic mixtures. There is also the possibility that a discrete mineral grain is composed of more than one clay type or has sections that are intermediate amongst two chosen minerals. Such minerals are alluded to as inter-stratified or mixed-layer minerals. The structures of clay minerals are the most researched compound in contemporary materials science. Tetrahedral sheets of clay minerals (TSCM) are one of the most well-known structures concentrated in materials science. QSPR/QSAR of the TSCM compounds requires articulations for the topological characteristic of these substances. Topological descriptors are indispensable gadgets for exploring chemical substances to understand the basic geography or physical properties of such chemical structures. In this article, we determine the edge-vertex-degree and vertex-edge-degree topological indices for TSCM.

Improving the separation of guaiacol from n-hexane by adding choline chloride to glycol extracting agents

Bio-oil is an important candidate to replace oil-derived products since it origins from renewable sources such as biomass. However, oxygenated bio-oil-based compounds require upgrading and further separation and purification for obtaining valuable compounds. Guaiacol is an important lignin derivative obtained from bio-oil, and it is a precursor for obtaining high-value-added molecules through heterogeneous catalysis. Alkanes are typical solvents for the guaiacol catalytical upgrading, so it is important to understand the extraction of guaiacol or guaiacol-like molecules from alkanes systems. This work reports the potential applicability of glycols and their corresponding eutectic mixtures with choline chloride as liquid–liquid extracting agents of guaiacol from n-hexane. The liquid–liquid equilibrium of six ternary systems composed of guaiacol + n-hexane + glycol or eutectic mixture is reported at 313.15 K and 101.3 kPa. Glycols selected as hydrogen bond donors were ethylene glycol, 1,2-propanediol, and 1,4-butanediol, while choline chloride was chosen as the hydrogen bond acceptor for preparing three eutectic mixtures using the glycols mentioned earlier. Density and viscosity of pure components and binary mixtures composed of guaiacol + glycols or guaiacol + eutectic mixture were measured at temperatures between 293.15 K and 333.15 K at 101.13 kPa. Density and liquid–liquid equilibrium data were modeled with PC-SAFT, and binary parameters were only used between the studied glycols and guaiacol. The results showed that the constituents of the eutectic mixtures did not distribute in the n-hexane phase, which was validated by NMR and GC. The viscosity of the pure components was correlated using PC-SAFT + Free Volume Theory, which allowed predicting the viscosity of mixtures by using binary parameters that were fitted to viscosity-independent data. The results obtained show that there is a high affinity between the guaiacol and the eutectic mixtures, based on observations about the negative excess volumes and the liquid–liquid equilibria. The eutectic mixtures are better for extracting guaiacol than their respective glycol-based constituents since they have higher selectivity and distribution coefficients and are larger miscibility gaps with the n-hexane phase compared to the studied glycols.

Protective role of strawberry tree (Arbutus unedo L.) honey against cyto/genotoxic effects induced by ultraviolet B radiation in vitro

Strawberry tree (Arbutus unedo L.) honey (STH) is widely used as part of traditional medicine in the Mediterranean area, especially in the treatment of wounds, burns and infections. In this study, we investigated the cyto-/genoprotective properties of STH at cell level following short-term exposure to UVB radiation at 2 kJ/m2. Isolated human peripheral blood lymphocytes (PBL) were selected as model cells. Phenolics in STH were determined using an ultra-high-performance liquid chromatograph (UHPLC) coupled to a linear ion trap-Orbitrap hybrid mass spectrometer (LTQ Orbitrap MS), while homogentisic acid (HGA) was quantified using a gas chromatograph-mass spectrometer (GC-MS). Primary DNA damage in PBLs treated with STH before and after irradiation was assessed by alkaline comet assay, while their viability was determined using the apoptosis/necrosis assay. The levels of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) were determined in plasma samples. STH applied as pre-treatment at a concentration equivalent to its average daily portion efficiently counteracted the cytotoxic and genotoxic effects and diminished UVB-induced oxidative stress. Post-radiation treatment with STH was not as beneficial. Protective effects could be associated to the complex phytochemical profile of STH and the high content of HGA (306.8 mg/kg). It was confirmed that an intake of a complex mixture of bioactive constituents as STH prior to potential cyto/genotoxic insults stimulated a broad-spectrum of protective mechanisms, including intracellular antioxidative defence and DNA repair systems that helped pre-treated cells to counteract harmful exposures more efficiently.

Reacting condensed phase explosives in direct contact

In this article, we present a new formulation and an associated algorithm for the simultaneous numerical simulation of multiple condensed phase explosives in direct contact with each other, which may also be confined by (or interacting with one or more) compliant inert materials. Examples include composite rate-stick (i.e., involving two explosives in contact) problems, interaction of shock waves with chemically active particles in condensed-phase explosives, and devices such as detonators and boosters. There are several formulations that address the compliant or structural response of confiners and particles due to detonations, but the direct interaction of explosives remains a challenge for most formulations and algorithms. The proposed formulation addresses this problem by extending the conservation laws and mixture rules of an existing hybrid formulation (suitable for solving problems involving the coexistence of reactants and products in an explosive mixture and its immiscible interaction with inert materials) to model the interaction of multiple explosive mixtures. An algorithm for the solution of the resulting system of partial differential equations is presented, which includes a new robust method for the retrieval of the densities of the constituents of each explosive mixture. This is achieved by means of a multi-dimensional root-finding algorithm, which employs physical as well as mathematical considerations in order to converge to the correct solution. The algorithm is implemented in a hierarchical adaptive mesh refinement framework and validated against results from problems with known solutions. Additional case studies demonstrate that the method can simulate the interaction of detonation waves produced by military grade and commercial explosives in direct contact, each with its own distinct equation of state and reaction rate law.

ANALYSIS OF THE BIOACTIVE AND MICROBIOLOGICAL CONTENTS OF HERBAL MIXTURES SOLD IN ANAMBRA STATE, NIGERIA

Over the years, medicinal plants have played a significant role in traditional medicine practice. The ever-increasing health-related difficulties and the search for possible treatments and likely cures have led to the increasing patronage of herbal drugs in Nigeria. There is an overwhelming increase in the production and distribution of herbal medications, and the trend has instigated concern about the quality of the products being sold in Anambra State, Nigeria. Thus, the primary purpose of the current study is to analyze the microbiological and phytochemical constituents of okanga powder, goko cleanser, and deep root herbal mixtures popularly sold in Nigeria. The phytochemical tests conducted on the herbal products revealed that the herbal products contain alkaloids, flavonoids, glycosides, anthraquinones, tannins, and saponins. The result of the microbial count indicates the presence of varying microorganisms such as S. aureus, E. coli, Salmonella, and Klebsiella spp in the herbal products. The study concludes that herbal products possess active phytochemicals. However, the presence of pathogenic organisms was discovered in the herbal drugs.

Treatment Technologies for Organics and Silica Removal in Steam-Assisted Gravity Drainage Produced Water: A Comprehensive Review

Produced water from steam-assisted gravity drainage (SAGD) operations is a complex mixture of inorganic and organic constituents. Silica, carbonate and bicarbonate, and hardness are three inorganic constituents of interest, whereas the organic contaminants are composed of free and emulsified oil (F&EO) and water-soluble organic (WSO) fractions. Although the current warm lime softening (WLS) and hot lime softening (HLS) in SAGD operations are able to remove particles, silica, and organics, improving the removal efficiency of organics and silica still faces technical and operational challenges given their complex chemistry in produced water. Much effort has been put toward developing effective and cost-efficient treatment processes to handle organics and silica. In this work, we have systematically reviewed the properties of silica and the characteristics of dissolved organics in SAGD produced water, as well as the working principle and removal mechanisms of several techniques, including membrane technology, adsorption, coagulation–flocculation, and hybrid processes. Different analytical techniques for characterizing dissolved organics have been assessed, and the dominant and representative organic species in produced water have been identified. The advantages and limitations, impact factors, application performance, and effectiveness of each technology have been discussed in terms of the removal efficiency for silica and organics. Some remaining challenges and perspectives for future research are also presented. This work provides an improved understanding of the characteristics of silica and organics in SAGD produced water, as well as different treatment technologies, with useful implications for developing effective, feasible, and cost-efficient treatment processes with the objective of enhancing the removal of silica and organics from produced water, thereby leading to economic and environmental performance improvements.

Sequential optical response suppression for chemical mixture characterization

The characterization of mixtures of non-interacting, spectroscopically similar quantum components has important applications in chemistry, biology, and materials science. We introduce an approach based on quantum tracking control that allows for determining the relative concentrations of constituents in a quantum mixture, using a single pulse which enhances the distinguishability of components of the mixture and has a length that scales linearly with the number of mixture constituents. To illustrate the method, we consider two very distinct model systems: mixtures of diatomic molecules in the gas phase, as well as solid-state materials composed of a mixture of components. A set of numerical analyses are presented, showing strong performance in both settings.

Interactions of nutrient and water availability control growth and diversity effects in a Salix two‐species mixture

AbstractPlant growth is constrained by resource availability and interactions among limiting resources—abundance in one resource (e.g., nutrients) might promote growth, thereby causing the depletion of other resources (e.g., water), potentially inducing stress or mortality. In a diverse plant community, complementary resource use has been hypothesized to increase the overall productivity, but how diversity effects vary with interacting water and nutrient limitation and through time is not known. Here, we address this knowledge gap in a controlled pot experiment where species composition (two Salix species in monoculture or mixture), nutrient addition, and watering frequency (for fixed total water inputs) were varied during two growing seasons. High nutrient availability promoted plant growth and nitrogen accumulation at the pot scale, as well as increased allocation aboveground, but also triggered more intense water stress and mortality, as larger plants depleted soil water during warm periods. Supplying water more frequently slightly alleviated water stress under high nutrient availability, thus promoting growth and nitrogen accumulation. The species mixtures performed better than the average of the mixture constituents (positive net diversity effects) and increasingly so through time. The complementarity and selection effects, respectively, increased and decreased under both high nutrient availability and high watering frequency. Overall, these results suggest that as plants grow larger, plant interactions and resource partitioning intensify, causing the positive diversity effects, but also that drought consequences might be exacerbated in plant communities rapidly growing thanks to high nutrient supply.

Role of multi-layered graphene as an additional fuel on energy release of Al/MoO3 nano-thermite

ABSTRACT Al/MoO3 nano-thermite is successfully reinforced with MLG (multi-layered graphene) using physical mixing synthesis technique, assisted with ultrasonication. MLG nanoplatelets in the nano-thermite (Al/MoO3) are utilised as an additional fuel to replace the conventional fuel, i.e. Al nanoparticles. The chemical composition and stability of samples are analysed by XRD (X-ray diffraction) and Raman techniques. The FESEM (field-emission scanning electron microscopy) and HR-TEM (high-resolution transmission electron microscopy) analysis revealed the morphology, uniform distribution of MoO3 (metal oxide) and Al, MLG (fuels) and also the contact between constituents of the thermite mixture. DSC (Differential scanning calorimetry) results showed that the exothermic behaviours are affected by the gradual replacement of Al by MLG as a fuel and achieved the maximum energy release of 1220 J/g, which is three times higher than 451 J/g, i.e. energy release in the case of Al/MoO3 conventional nano-thermite.

Mapping the Physical Properties of Soils and the California Bearing Ratio (CBR) Value for Different Soil Types: A Case Study in the Bukit Kemuning and Pugung Tampak Areas

It is widely accepted that soil is a mixture of mineral constituents that have accumulated over time. The physical characteristics of soil vary according to the mineral and organic matter content and the process of formation. The soil`s unique characteristics have been the subject of research in the field of civil engineering, which has continued to evolve to the present day due to the land`s requirement for civil engineering construction, such as road paving. As a result, the current study sought to determine the similarity of soil samples based on their physical properties and California Bearing Ratio (CBR) values, as well as the relationship between the soil`s physical properties and CBR values. To our knowledge, there is hardly little research in the literature investigating the topic under our investigation. Furthermore, we also mapped the physical characteristics and CBR values of numerous distinct soil samples using a Geographical Information System (GIS). This study concentrated on the West Lampung Regency, specifically the area between Bukit Kemuning in Central Lampung and Liwa in West Lampung, along the lines of Bukit Kemuning, Liwa, and Krui, all the way to the Lampung – Bengkulu province border. The soil samples from the area were taken for two tests: the unsoaked CBR test and the soaked CBR test. The results of the tests show that a 31-kilometre distance does not result in a significant difference in soil properties, which are generally similar except in clay-rich areas. Furthermore, the results of the laboratory analysis show that the amount of water in the soil sample affects the Liquid Limit (LL), Plastic Limit (PL), Maximum Dry Density (MDD), and CBR values; the lower the plastic limit value, and thus the lower the CBR value, the less water in the soil. The implications of the current findings are also discussed.

Optimizacija dizajna kalupa za ulivanje termitnog čelika kod aluminotermijskog zavarivanja železničkih šina softverskom simulacijom

The aluminothermic welding process of rail welding has been used to join railway rails for more than a century. The benefits of this procedure include its flexibility, compactness of the weld, and ease of execution. It is not necessary to bring in outside energy to complete the process. It is provided by the exothermic effect of the chemical reactions of the aluminothermic mixture's constituents. The design of the mold with the pouring system, which should ensure even pouring of thermal steel, without turbulence, then even heat dissipation or cooling in order to obtain appropriate micro and macro structure of steel, without internal and external defects, is an important element for making a welded joint of the required quality. As a result, the mold's design was constantly evolving, requiring the use of costly experimental methods in industrial settings. Today, software packages are used to simulate traditional casting processes that can be used in the casting of thermite steel during the manufacture of welded railway joints, thereby avoiding costly and time-consuming industrial tests. The simulation of casting thermite steel in the mold cavity, i.e. in the weld joint for the 49E1 rail, using the NovaFlow & Solid CV software package, is presented in this paper. The simulation results were validated by establishing test welded joints in industrial settings and testing their quality in accordance with the EU 13740-1: 2017 standard.

Continuum Thermodynamics of Constrained Reactive Mixtures.

Mixture theory models continua consisting of multiple constituents with independent motions. In constrained mixtures, all constituents share the same velocity but they may have different reference configurations. The theory of constrained reactive mixtures was formulated to analyze growth and remodeling in living biological tissues. It can also reproduce and extend classical frameworks of damage mechanics and viscoelasticity under isothermal conditions, when modeling bonds that can break and reform. This study focuses on establishing the thermodynamic foundations of constrained reactive mixtures under more general conditions, for arbitrary reactive processes where temperature varies in time and space. By incorporating general expressions for reaction kinetics, it is shown that the residual dissipation statement of the Clausius-Duhem inequality must include a reactive power density, while the axiom of energy balance must include a reactive heat supply density. Both of these functions are proportional to the molar production rate of a reaction, and they depend on the chemical potentials of the mixture constituents. We present novel formulas for the classical thermodynamic concepts of energy of formation and heat of reaction, making it possible to evaluate the heat supply generated by reactive processes from the knowledge of the specific free energy of mixture constituents as well as the reaction rate. We illustrate these novel concepts with mixtures of ideal gases, and isothermal reactive damage mechanics and viscoelasticity, as well as reactive thermoelasticity. This framework facilitates the analysis of reactive tissue biomechanics and physiological and biomedical engineering processes where temperature variations cannot be neglected.

Selection of Representative Constituents for Unknown, Variable, Complex, or Biological Origin Substance Assessment Based on Hierarchical Clustering.

Many of the newly produced and registered substances are complex mixtures or substances of unknown or variable composition, complex reaction products, and biological materials (UVCBs). The latter often consist of a large number of constituents, some of them difficult-to-identify constituents, which complicates their (eco)toxicological assessment. In the present study, through a series of examples, different scenarios for selection of representatives via hierarchical clustering of UVCB constituents are exemplified. Hierarchical clustering allows grouping of the individual chemicals into small sets, where the constituents are similar to each other with respect to more than one criterion. To this end, various similarity criteria and approaches for selection of representatives are developed and analyzed. Two types of selection are addressed: (1) selection of the most "conservative" constituents, which could be also used to support prioritization of UVCBs for evaluation, and (2) obtaining of a small set of chemical representatives that covers the structural and metabolic diversity of the whole target UVCBs or a mixture that can then be evaluated for their environmental and (eco)toxicological properties. The first step is to generate all plausible UVCB or mixture constituents. It was found that the appropriate approach for selecting representative constituents depends on the target endpoint and physicochemical parameters affecting the endpoint of interest. Environ Toxicol Chem 2021;40:3205-3218. © 2021 SETAC.

Is discourse made up of sentences? Focusing on dependent grafted speech in modern standard Japanese

AbstractThe idea that discourse is made up of sentences has been widespread among linguists. Does this traditional discourse perspective (“sententialism”) apply to casual language in daily communication? This paper examines the validity of sententialism by focusing on a type of speech called “dependent grafted speech” in Japanese conversation. Close examinations of various words, phrases, and sentences reveal that dependent grafted speech is different from sentences on two points: (i) Generally, the lexical accent of the copula at the beginning of dependent grafted speech is a high tone; and (ii) the interaction particle at the end of dependent grafted speech is not uttered with a falling intonation unless it is proceeded by a very abrupt rising intonation (“leaping” intonation). These findings cast doubt on the status of dependent grafted speech as a sentence. Moreover, they demonstrate a new conception of discourse as a mixture of diverse constituents, including sentences, dependent grafted speech, and other utterance types.