Extent Of Hydration Research Articles

18-month hydration of a low-pH cement for geological disposal of radioactive waste: The Cebama reference cement

Low-pH cements are candidate materials for use in the construction of geological disposal facilities for the long-term management of nuclear waste. Since these facilities will operate over long time scales, the changes in mineralogy and microstructure require evaluation as a function of time. As a first step towards this understanding, the hydration of a standardised low-pH cement paste, known as the Cebama reference cement, was investigated over an 18-month period. Characterisation was performed at 28 days of curing, at 20 °C and 40 °C, and novel synchrotron radiation X-ray diffraction experiments were performed, in-situ, from 90 min to 18 months of curing. Concurrent solid state 29Si and 27Al MAS NMR data were acquired for parallel samples to quantify the extent of cement hydration and the composition and mean chain length of the predominant calcium aluminosilicate hydrate (C-(A)-S-H) reaction product. After 18 months, cement clinker phases were still present, highlighting the slow hydration kinetics of this low-pH cement. The data presented provide a benchmark for ongoing and future studies of low-pH cements in geological disposal environments, over extended time scales.

Electric field assisted desalination of water using B- and N-doped-graphene sheets: A non-equilibrium molecular dynamics study

The possibility and mechanism of water desalination using newly designed doped graphene sheets is reported. It is hereby demonstrated, through molecular dynamics (MD) simulations, that an electric field-assisted selective ion separation is possible using boron- and nitrogen-doped nano-porous graphene sheets. The sheets are shown to behave as nano-sponges, with potential future applications in water desalination by electrodialysis, for example. Ion separation is found to increase as the extent of ion hydration decreases under increasing field strengths. Boron- and nitrogen-doped graphene sheets are found to exhibit acceptable mechanical properties and, simultaneously, good ion selectivities and that they may be candidates for future technological applications in desalination and other refining processes.

Effects of Blackcurrant Fibre on Dough Physical Properties and Bread Quality Characteristics

Wheat flour was partially replaced with blackcurrant pomace, soluble, and insoluble dietary fibre in dough and bread formulations. The impact of blackcurrant fibre on physical properties of doughs and breads was probed using a set of complementary physicochemical techniques. The effect of fibre on aromatic profile of substituted breads was performed using analysis of volatile compounds. Analysis of fibre-substituted doughs and breads revealed that supplementation with pomace or insoluble fibre at concentrations >5% w/w or with pectin at concentrations >0.5% w/w alters their overall physicochemical responses. Pomace and pectin primarily acted as water-binders and decreased the extent of gluten hydration but insoluble fibre did not bind water to the same extent suggesting higher interaction capacity between its cellulosic components and gluten proteins resulting in formation of stiffer doughs. More than one hundred volatiles were determined with alcohols, furan derivatives and aldehydes being the major aromatic compounds.

The extent of protein hydration dictates the preference for heterogeneous or homogeneous nucleation generating either parallel or antiparallel β-sheet α-synuclein aggregates.

α-Synuclein amyloid self-assembly is the hallmark of a number of neurodegenerative disorders, including Parkinson's disease, although there is still very limited understanding about the factors and mechanisms that trigger this process. Primary nucleation has been observed to be initiated in vitro at hydrophobic/hydrophilic interfaces by heterogeneous nucleation generating parallel β-sheet aggregates, although no such interfaces have yet been identified in vivo. In this work, we have discovered that α-synuclein can self-assemble into amyloid aggregates by homogeneous nucleation, without the need of an active surface, and with a preference for an antiparallel β-sheet arrangement. This particular structure has been previously proposed to be distinctive of stable toxic oligomers and we here demonstrate that it indeed represents the most stable structure of the preferred amyloid pathway triggered by homogeneous nucleation under limited hydration conditions, including those encountered inside α-synuclein droplets generated by liquid-liquid phase separation. In addition, our results highlight the key role that water plays not only in modulating the transition free energy of amyloid nucleation, and thus governing the initiation of the process, but also in dictating the type of preferred primary nucleation and the type of amyloid polymorph generated depending on the extent of protein hydration. These findings are particularly relevant in the context of in vivo α-synuclein aggregation where the protein can encounter a variety of hydration conditions in different cellular microenvironments, including the vicinity of lipid membranes or the interior of membraneless compartments, which could lead to the formation of remarkably different amyloid polymorphs by either heterogeneous or homogeneous nucleation.

Influence of surface hydrophilicity and hydration on the rotational relaxation of supercooled water on graphene oxide surfaces.

Hydration or interfacial water present in biomolecules and inorganic solids has been shown to exhibit a dynamical transition upon supercooling. However, understanding the extent of the underlying surface hydrophilicity as well as the local distribution of hydrophilic/hydrophobic patches on the dynamical transition is unexplored. Here, we use molecular dynamics simulations with a TIP4P/2005 water model to study the translational and rotational relaxation dynamics of interfacial water on graphene surfaces. The purpose of this study is to investigate the influence of both the surface chemistry and the extent of hydration on the rotational transitions of interfacial water on graphene oxide (GO) surfaces in the deeply supercooled region. We have considered three graphene-based surfaces: a GO surface with equal proportions of oxidized and pristine graphene regions in a striped topology, a fully oxidized surface and a pristine graphene surface. The dipole relaxation time of interfacial water (high hydration) shows a strong-to-strong transition, strong nature, and strong-to-strong transition on these surfaces, respectively, in the temperature range of 210-298 K. In contrast, bulk water shows a fragile-to-strong rotational transition upon supercooling. In all these cases at high hydration, interfacial water co-exists with a thick water film with bulk-like properties. To investigate the influence of bulk water on dynamical transitions, we simulated a low hydration regime where only bound water (surface water) is present on the GO surfaces and found that the rotational relaxation of surface water on both the GO and fully oxidized surfaces shows a single Arrhenius temperature dependence. Bulk water is found to have a greater influence on the rotational relaxation in the presence of a hydrophobic surface and the dipole angular distributions show distinct differences on the surfaces upon supercooling. Our results indicate that not only does the local extent of surface hydrophilicity play a role in determining the energy landscape explored by the water molecules upon supercooling, but the presence of bulk water also modulates the dynamic transition.

Impact of granule hydration on maize and wheat starch chemical reactivity at the granular and molecular levels

Granular and molecular reaction patterns of maize and wheat starches (normal and waxy genotypes) were investigated in relation to extent of granule hydration (equilibrated at 25, 55, 75, 86 or 100% relative humidity [RH]; moisture range ≈ 10–40 g/100 g starch) within a model reaction system utilizing a fluorescent reagent (5-(4,6-dichlorotriazinyl)aminofluorescein). The greatest incremental increase in granule hydration (49–80%) and overall extent of reaction (30-76-fold) occurred between 86 and 100% RH, likely accentuating the starch glass transition temperature (Tg), which was depressed to room temperature via gradual granule hydration. Under limited hydration conditions (25–86% RH; presumably below Tg), reaction was confined to granule surfaces, whereas under conditions of sufficient hydration/plasticization (100% RH; presumably above Tg), reaction occurred throughout the granule matrix, dramatically increasing reaction of amylose and amylopectin branch chains. For normal starches, amylose was more inert to reaction in low moisture conditions (25–87% RH), indicating either a lesser prevalence at granular surfaces or insufficient hydration to react. Waxy starches exhibited more homogenous granular reaction patterns and greater overall extents of reaction than their respective normal starch counterparts, due to reactivity differences amongst amylose and amylopectin medium and long chains. Findings also provide insights for manipulating granular/molecular reaction locale in “dry” starch modifications.

Aptamer-Anchored Rubrene-Loaded Organic Nanoprobes for Cancer Cell Targeting and Imaging

Aptamer-Anchored Rubrene-Loaded Organic Nanoprobes for Cancer Cell Targeting and Imaging

1-nm-Wide Hydrated Dipole Arrays Regulate AuNW Assembly on Striped Monolayers in Nonpolar Solvent

Summary We show that striped phases of horizontally oriented phospholipids presenting 1-nm-wide orientable dipole arrays can order and straighten flexible 2-nm-diameter gold nanowires (AuNWs) with lengths (up to 1 μm) that greatly exceed the template pitch (∼7.5 nm). AuNW ordering can extend over areas > 100 μm2. Whereas wires bundle in solution, with contact between ligand shells, wires adsorbing to the template separate to much larger center-to-center distances (e.g., 12–30 nm) near multiples of the template pitch, consistent with repulsive interactions between wires emerging during interactions with dipole arrays in the template. AuNW assembly was carried out in cyclohexane, a nonpolar solvent. Interestingly, we found that wire ordering was contingent on the extent of phospholipid headgroup hydration and the presence of excess oleylamine, which assembled into hemicylindrical micelles around the hydrated headgroups. Together, these components generated a protected polar environment that enabled the phospholipid headgroups to function collectively to regulate AuNW assembly.

A structural model of the human serotonin transporter in an outward-occluded state.

The human serotonin transporter hSERT facilitates the reuptake of its endogenous substrate serotonin from the synaptic cleft into presynaptic neurons after signaling. Reuptake regulates the availability of this neurotransmitter and therefore hSERT plays an important role in balancing human mood conditions. In 2016, the first 3D structures of this membrane transporter were reported in an inhibitor-bound, outward-open conformation. These structures revealed valuable information about interactions of hSERT with antidepressant drugs. Nevertheless, the question remains how serotonin facilitates the specific conformational changes that open and close pathways from the synapse and to the cytoplasm as required for transport. Here, we present a serotonin-bound homology model of hSERT in an outward-occluded state, a key intermediate in the physiological cycle, in which the interactions with the substrate are likely to be optimal. Our approach uses two template structures and includes careful refinement and comprehensive computational validation. According to microsecond-long molecular dynamics simulations, this model exhibits interactions between the gating residues in the extracellular pathway, and these interactions differ from those in an outward-open conformation of hSERT bound to serotonin. Moreover, we predict several features of this state by monitoring the intracellular gating residues, the extent of hydration, and, most importantly, protein-ligand interactions in the central binding site. The results illustrate common and distinct characteristics of these two transporter states and provide a starting point for future investigations of the transport mechanism in hSERT.

Discrete Optimization of Software-Controlled Modes of Heat Treatment of Concrete Products in Heat-Technological Facilities

In the article the technique of an assessment of modes of operation of the heat engineering equipment used for heat treatment of concrete products in the conditions of programcontrolled heat supply according to the pattern of “heating – isothermal influence – cooling” has been developed. The method is based on the numerical solution of a non-stationary heat equation supplemented by equations describing the hydration process of a concrete product; also, it includes a system of initial and boundary conditions for its spatial structure. The method makes it possible to create tabulated functions of temperature and the degree of hydration of the time of heat treatment in any point of a 3D-product. The mathematical tools for calculating the functional dependencies of concrete hydration equipment with software-heated environment are presented. Numerical calculations of the concrete hydration process in the formwork are performed with respect to the symmetrical object. Based on the calculation of the temperature gradient across the minimal cross section of the product, a numerical analysis of the functions modeling heat supply mode depending on the processing time of a concrete product has been fulfilled. It is demonstrated that the maximum speed of the hydration process in a concrete product hardening is achieved at the maximum of time lag of isothermal cure. Additionally, with an increase in the duration of the product heating, the value of the maximum hydration rate decreases. It is concluded that the method of assessing the mode of heat treatment of concrete products being developed makes it possible to determine parameters for the calculation of the minimal useful heat required for the heat treatment of concrete products with spatially distributed parameters. The proposed method is applicable to calculate the temperature fields and the extent of hydration in the products of any geometric shape and volume in a software-controlled heating environment of industrial facilities for the accelerated hydration of concrete, and also affords the possibility of preliminary calibration prior to the assignment of relevant heat supply modes to the products being processed.

The Application of 29Si NMR Spectroscopy to the Analysis of Calcium Silicate-Based Cement using Biodentine™ as an Example.

Biodentine is one of the most successful and widely studied among the second generation of calcium silicate-based endodontic cements. Despite its popularity, the setting reactions of this cement system are not currently well understood. In particular, very little is known about the formation and structure of the major calcium silicate hydrate (C-S-H) gel phase, as it is difficult to obtain information on this poorly crystalline material by the traditional techniques of powder X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). In this study, the hydration reactions of Biodentine are monitored by XRD, FTIR, isothermal conduction calorimetry and, for the first time, 29Si magic angle spinning nuclear magnetic resonance spectroscopy (29Si MAS NMR) is used to investigate the structures of the anhydrous calcium silicate phases and the early C-S-H gel product. XRD analysis indicated that the anhydrous powder comprises 73.8 wt% triclinic tricalcium silicate, 4.45 wt% monoclinic β-dicalcium silicate, 16.6 wt% calcite and 5.15 wt% zirconium oxide. Calorimetry confirmed that the induction period for hydration is short, and that the setting reactions are rapid with a maximum heat evolution of 28.4 mW g−1 at 42 min. A progressive shift in the FTIR peak maximum from 905 to 995 cm−1 for the O-Si-O stretching vibrations accompanies the formation of the C-S-H gel during 1 week. The extent of hydration was determined by 29Si MAS NMR to be 87.0%, 88.8% and 93.7% at 6 h, 1 day and 1 week, respectively, which is significantly higher than that of MTA. The mean silicate chain length (MCL) of the C-S-H gel was also estimated by this technique to be 3.7 at 6 h and 1 day, and to have increased to 4.1 after 1 week. The rapid hydration kinetics of Biodentine, arising from the predominance of the tricalcium silicate phase, small particle size, and ‘filler effect’ of calcite and zirconium oxide, is a favorable characteristic of an endodontic cement, and the high values of MCL are thought to promote the durability of the cement matrix.

Counteracting Effect of Charged Amino Acids Against the Destabilization of Proteins by Arginine.

Studies on osmolyte-induced effects on proteins help in enhancing protein stability under stressed conditions for various applications. Using mixtures of osmolytes could indeed widen their applications. The combinatorial effects of osmolytes with methylamines are majorly found in the literature; however, such studies are limited on the amino acid class of osmolytes. The present study examines the effect of charged amino acids Arg, Asp, and Lys on the stability of RNase A and α-LA. The thermal stabilities of the proteins in the presence of osmolytes are monitored by absorption changes, and the structural changes are analyzed using fluorescence quenching and near-UV circular dichroism (CD). These results are compared with our previous report on the effect of Glu. Arg destabilizes both the proteins whereas Asp, Lys, and Glu stabilize the proteins. The extent of stability provided by Asp and Glu is almost same and higher than Lys in RNase A. However, the stability acquired in the presence of Asp and Lys is comparable for α-LA and Glu provides higher stability. Further, the quenching and CD results suggest that the addition of amino acids do not alter the structure of the proteins significantly. The counteracting abilities of the stabilizing amino acids (stAAs) against Arg are then investigated. The results show that Glu could counteract Arg at the lowest fraction in the mixture. Lys requires nearly equimolar concentration whereas Asp needs almost double the concentration to counteract Arg induced destabilization of the proteins. At higher concentrations, the counteracting ability of Asp and Lys is similar for both the proteins. The counteracting ratio might slightly vary among the proteins, and it is not necessary that the amino acid providing higher stability to the protein could more effectively counteract Arg. This could be due to the change in the extent of preferential hydration of the proteins by stAAs in the presence of Arg. The results suggest that the addition of stAAs could be an effective strategy to increase the protein stability in biotechnology and biopharma applications.

Self‐assembled polyurea macromer nanodispersion and resulting hybrid polyurea‐acrylic emulsions and films

ABSTRACTA polyurea macromer (PUM) was synthesized and dispersed in basic conditions to form self‐assembled nanoparticles (<20 nm dispersions, up to 30 wt % aq. soln.). These nanoparticles enabled surfactant‐free emulsion polymerization to form hybrid polyurea‐acrylic particles despite the absence of a measureable water‐soluble fraction. The Tg of the starting PUM material was a strong function of the PUM's extent of neutralization and hydration (varying between 100 °C and >175 °C) due to changes in hydrogen and ionic bonding. Two separate hybrid polyurea‐acrylic emulsion systems were prepared: one by direct polymerization of (meth)acrylic monomers in the presence of the nanodispersion and a second by a physical blend of PUM nanodispersion with an acrylic latex control. The direct polymerization method resulted in a hybrid emulsion particle size that developed by a mechanism resembling conventional emulsion polymerization and was unlike that described for seeded polyurethane dispersion systems. Film hardness was shown to increase with increasing coating thickness for the hybrid film prepared by direct polymerization. The resulting mechanical properties could be explained by applying mechanical models for a composite foam structure. These results were unprecedented for normal elastomer films. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1373–1388

Molecular dynamics simulation of the hydration of adenosine phosphates

The hydration behavior of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) has been investigated with molecular dynamics simulations. The spatial distribution of water molecules around different hydration sites of the adenosine phosphates and the average times that water molecules spend in the vicinity of the hydration sites of the phosphate, ribose, and adenine groups have been examined in order to characterize the hydration extent of different regions of the ATP, ADP, and AMP molecules. The water molecules strongly hydrate the negatively-charged phosphate groups of the adenosine phosphates and the interaction between the oxygen and nitrogen atoms of the ribose and adenine rings with water molecules lead to the full hydration of these groups by the water molecules as well. The adenosine phosphates ATP, ADP, and AMP were found to be fully hydrated by the water molecules regardless of the magnitude of their negative charges. Results of this work provide atomic-level information about the hydration of ATP, ADP, and AMP were and are expected to help better understand the behavior of these molecules in biological systems.

Hydration and nanomechanical changes in collagen fibrils bearing advanced glycation end-products.

Accumulation of advanced glycation end-products (AGEs) in biological tissues occurs as a consequence of normal ageing and pathology. Most biological tissues are composed of considerable amounts of collagen, with collagen fibrils being the most abundant form. Collagen fibrils are the smallest discernible structural elements of load-bearing tissues and as such, they are of high biomechanical importance. The low turnover of collagen cause AGEs to accumulate within the collagen fibrils with normal ageing as well as in pathologies. We hypothesized that collagen fibrils bearing AGEs have altered hydration and mechanical properties. To this end, we employed atomic force and Brillouin light scattering microscopy to measure the extent of hydration as well as the transverse elastic properties of collagen fibrils treated with ribose. We find that hydration is different in collagen fibrils bearing AGEs and this is directly related to their mechanical properties. Collagen fibrils treated with ribose showed increased hydration levels and decreased transverse stiffness compared to controlled samples. Our results show that BLS and AFM yield complementary evidence on the effect of hydration on the nanomechanical properties of collagen fibrils.

Hydroxyectoine protects Mn-depleted photosystem II against photoinhibition acting as a source of electrons.

In the present study, we have investigated the effect of hydroxyectoine (Ect-OH), a heterocyclic amino acid, on oxygen evolution in photosystem II (PS II) membrane fragments and on photoinhibition of Mn-depleted PS II (apo-WOC-PS II) preparations. The degree of photoinhibition of apo-WOC-PS II preparations was estimated by the loss of the capability of exogenous electron donor (sodium ascorbate) to restore the amplitude of light-induced changes of chlorophyll fluorescence yield (∆F). It was found that Ect-OH (i) stimulates the oxygen-evolving activity of PS II, (ii) accelerates the electron transfer from exogenous electron donors (K4[Fe(CN)6], DPC, TMPD, Fe2+, and Mn2+) to the reaction center of apo-WOC-PS II, (iii) enhances the protective effect of exogenous electron donors against donor-side photoinhibition of apo-WOC-PS II preparations. It is assumed that Ect-OH can serve as an artificial electron donor for apo-WOC-PS II, which does not directly interact with either the donor or acceptor side of the reaction center. We suggest that the protein conformation in the presence of Ect-OH, which affects the extent of hydration, becomes favorable for accepting electrons from exogenous donors. To our knowledge, this is the first study dealing with redox activity of Ect-OH towards photosynthetic pigment-protein complexes.

Impact of Temperature on the Strength Development of the Tailing‐Waste Rock Backfill of a Gold Mine

This study investigated the influencing rules of curing temperature (5, 10, 16, and 20°C), cement ratio (8%, 10%, 12%, and 14%), and mass concentration (70%, 73%, 74%, and 75%) on the strength of backfill. In addition, a scanning electron microscope (SEM) is employed to analyze the microtopography of the backfill. Experimental results indicate that the uniaxial compressive strength (UCS) of the backfill decreases as the curing temperature diminishes; temperature substantially influences the earlier strength of backfill (it is much significant below 10°C). In addition, as the cement ratio rises, the critical point for the impact of temperature on strength gradually moves toward a low‐temperature zone; in pace with the slurry mass concentration increase, the compressive strength of the backfill also rises and its rate of increase enlarges after going beyond the critical concentration. In case the curing temperature is lower than 10°C, the extent of hydration is also low inside the backfill. Through experiments, the critical concentration of slurry in the Jinying gold mine is determined as 73%, and the critical interval of the cement ratio ranged between 10% and 12%. Corresponding measures can be taken to increase the strength of backfill in the Jinying Gold Mine by 129.9%. As a result, backfill collapse is effectively controlled.

Melt Impregnation of Mantle Peridotite Facilitates High‐Temperature Hydration and Mechanical Weakening: Implications for Oceanic Detachment Faults

AbstractThe footwalls of oceanic detachment faults commonly expose shear zone rocks that appear to have compositions intermediate between those of mantle peridotite and magmatic rocks. These compositions either reflect metasomatic mass transfers or they relate to the impregnation of lithospheric mantle with basaltic or more evolved melts. We studied chlorite‐amphibole‐rich shear zone rocks from a detachment fault zone in the 15°20′N Fracture Zone area, Mid‐Atlantic Ridge, to examine their origin and role in strain localization. Geochemical compositions of these rocks imply that they formed by mixing between peridotite and gabbro. Textural observations indicate a strong contrast between the deformation intensity of these hybrid peridotite‐gabbro rocks and the host serpentinized peridotite. Geothermometry data give formation temperatures of >500 °C for synkinematic amphibole, zircon, rutile, and titanite. Chlorite appears intergrown with these phases and likely grew at similar temperatures. These results are compliant to thermodynamic computations that predict comparable mechanically weak mineralogies when hydrating hybrid rocks at 500 to 600 °C, whereas secondary assemblages after pure peridotite or gabbro are considerably stronger. Consequently, metamorphic weakening takes place to a much greater extent in rocks with a hybrid ultramafic–mafic composition than in purely ultramafic or gabbroic lithologies. Deformation may enhance fluid flow, which will in turn increase the extent of hydration and mechanical weakening. A positive feedback loop between hydration and strain localization may hence develop and facilitate the concentration of extensional tectonics into long‐lived, high‐displacement faults. We suggest that hybrid lithologies may play a key role in detachment faulting at slow spreading ridges worldwide.

Water input into the Mariana subduction zone estimated from ocean-bottom seismic data.

The water cycle at subduction zones remains poorly understood, although subduction is the only mechanism for water transport deep into Earth. Previous estimates of water flux1-3 exhibit large variations in the amount of water that is subducted deeper than 100 kilometres. The main source of uncertainty in these calculations is the initial water content of the subducting uppermost mantle. Previous active-source seismic studies suggest that the subducting slab may be pervasively hydrated in the plate-bending region near the oceanic trench4-7. However, these studies do not constrain the depth extent of hydration and most investigate young incoming plates, leaving subduction-zone water budgets for old subducting plates uncertain. Here we present seismic images of the crust and uppermost mantle around the central Mariana trench derived from Rayleigh-wave analysis of broadband ocean-bottom seismic data. These images show that the low mantle velocities that result from mantle hydration extend roughly 24 kilometres beneath the Moho discontinuity. Combined with estimates of subducting crustal water, these results indicate that at least 4.3 times more water subducts than previously calculated for this region3. If other old, cold subducting slabs contain correspondingly thick layers of hydrous mantle, as suggested by the similarity of incoming plate faulting across old, cold subducting slabs, then estimates of the global water flux into the mantle at depths greater than 100 kilometres must be increased by a factor of about three compared to previous estimates3. Because a long-term net influx of water to the deep interior of Earth is inconsistent with the geological record8, estimates of water expelled at volcanic arcs and backarc basins probably also need to be revised upwards9.

Metal Coordination Polymer Framework Governed by Heat of Hydration for Noninvasive Differentiation of Alkali Metal Series.

We illustrate that the extent of hydration and consequently the heat of hydration of alkali metal ions can be utilized to control their insertion/deinsertion chemistry in a redox active metal coordination polymer framework (CPF) electrode. The formal redox potential of CPF electrode for cation intercalation is inversely correlated to hydrated ionic radii, with clear distinction between the intercalation of ions across alkali metal series. This leads to noninvasive identification and differentiation of cations in the alkali metal series by utilizing a single sensing platform.