Prostate cancer (PC) is the sixth most common cancer type in the world, which causes approximately 10% of total cancer fatalities. The detection of protein biomarkers in body fluids is the key topic for the diagnosis and prognosis of PC. Highly sensitive screening of PC is the most effective approach for reducing mortality. Thus, there are a growing number of literature that recognizes the importance of new technologies for early diagnosis of PC. Graphene is playing an important role in the biosensor field with remarkable physical, optical, electrochemical and magnetic properties. Many recent studies demonstrated the potential of graphene materials for sensitive detection of protein biomarkers. In this review, the graphene-based biosensors toward PC analysis are mainly discussed in two groups: Firstly, novel biosensor interfaces were constructed through the modification of graphene materials onto sensor surfaces. Secondly, ingenious signal amplification strategies were developed using graphene materials as catalysts or carriers. Graphene-based biosensors have exhibited remarkable performance with high sensitivities, wide detection ranges, and long-term stabilities. PC is one of the most common cancers in the world which causes a fatality of approximately 10% in all cancer patients . PC is aTumor markers for early clinical screening and rapid diagnosis cover a wide range of biochemical entities, including, proteins , 14, nucThis review highlights recent graphene-based biosensors for PC protein biomarkers detection. As far as we know, this is the first review that focuses on specific one disease. We reviewed recent progress of graphene-based biosensors for PC protein biomarker detection. Our manuscript clearly stated the advantages and shortcomings of most of the graphene-based when facing PC diagnosis, thus, the manuscript should be valuable for the future application of graphene-based biosensors.Protein biomarkers for cancer diagnosis are usually produced by either cancer cells or other cells in response to cancer –34, whicProstate-specific antigen (PSA) , which iProstate-specific membrane antigen (PSMA)  is a typ2-bonded carbon atoms. GO is chemically produced by oxidation and exfoliation of graphene, causing extensive oxidative modification of the basal plane [Graphene is a two-dimensional (2D) nanomaterial, which plays an important role in the biosensor field –66. The al plane , 75–77. al plane –80. GQDsal plane , 82.Development of protein biosensors based on graphene could be classified into two main groups Fig. : FirstlyGraphene and its derivatives are studied for the construction of novel biosensor interface , which i2) was used for the assembling of antibody on novel biosensor interfaces [2 combining, with the assistant of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and they finally achieved a low detection limit of 2 pg/mL [Traditionally, antibodies are physically adsorbed onto the immune-assay surfaces, such as classic 96-well plates and colloidal gold test strips. However, one of the main obstacles is the affinity and capacity, because the hydrophobic and hydrophilic interaction is relatively weak and the orientation of the antibody molecules is random . As seveterfaces , 91. In  2 pg/mL .In order to realize better-oriented assembling of antibody, Mao et al. applied chitosan as the dispersant to construct an immuno-interface on a glassy carbon electrode Fig. A, which A graphene-modified electrode was also reported in ECL biosensor  for PSA Vg,min) was achieved, indicating the minimum conductivity. Finally, they successfully performed detection of PSA-ACT of femtomolar level.Graphene materials were also applied in FET biosensors, for the construction of 2D nano-FET biosensors –101, witFor interface-based PC biosensors, the DNA capture probe plays a key role, which could recognize and capture the target molecules . The ver4, then SH-labeled DNA aptamer was combined to Au on the electrode surface. Finally, their aptasensor achieved 1.0 pg/mL limit of detection (LOD) by using both DPV and ESI methods. Different chemical reactions were applied for the assembling of DNA onto graphene materials. Branched polyethylenimine (PEI) was applied by Pan et al. to connect thiol-mediated ssDNA onto carboxylated GO for PSA detection [As the first step toward an aptasensing platform, scientists developed several different strategies to assemble the DNA aptamer onto the electrode as the key recognition element –117. In etection . Recentletection .2O2, producing a brown color solution. Thus, they produced an antibody-functionalized GO as the signal tag and developed a sandwich-type colorimetric immunoassay for the detection of PSA. In their work [2) and magnetic bead (MB) with primary anti-PSA antibody (MB-Ab1). After the separation in a magnetic field, the color signal was detected corresponding to the concentration of PSA. Their simple immunoassay can be detected by naked eyes , generating a current signal [3N4) with large surface area, good biocompatibility, and excellent conductivity were used as labels for combining secondary antibodies and amplifying signals. Then secondary antibodies were combined onto this platform and signals were amplified from H2O2 reduction [Han et al. developed a novel signal tag for PSA and free PSA (fPSA) detection, by using onion-like mesoporous graphene sheets (O-GS) as the carrier of different AuNP-based nanohybrids . As the t signal . Feng eteduction .3O4 nanoparticles together with antibody onto GO sheets to produce a multi-function nanocomposite  were used in PC biosensor development and most of them were combined with other nanomaterials like nanoparticles. We have also summarized various strategies and approaches which can be used for graphene-based biosensor development. Graphene-based materials were used not only for novel biosensor interfaces construction but also as excellent carriers for the construction of novel nanocomposites for signal amplification. In most of the cases, graphene-based biosensors have exhibited satisfactory biocompatibility towards the bioactive species and remarkable performance with high sensitivities, wide linear detection ranges, low detection limits and long-term stabilities Table . As otheAlthough tremendous progress has been made in the past a few years of graphene-based biosensors for PC detection, there still remain some challenges. Firstly, PSA has been demonstrated not a specific biomarker in prostate cancer early screening. As a result, detection of multiple biomarkers is crucial for precise diagnosis and prognosis of PC , 131. Mo


Graphene-based quantised Hall resistance standards promise high precision for the unit ohm under less exclusive measurement conditions, enabling the use of compact measurement systems. To meet the requirements of metrological applications, national metrology institutes developed large-area monolayer graphene growth methods for uniform material properties and optimized device fabrication techniques. Precision measurements of the quantized Hall resistance showing the advantage of graphene over GaAs-based resistance standards demonstrate the remarkable achievements realized by the research community. This work provides an overview over the state-of-the-art technologies in this field. The laser, for example, has made standards of length inexpensive and accurate in terms of another easily accessed quantum standard, the global positioning system (GPS) broadcast . ElectriThe emergence of epitaxial graphene (EG), grown with intrinsic structural alignment on SiC crystals, is allowing the metrology community to realize the extraordinary precision of the new QHR standard more efficiently. This material is produced by sublimation of Si from nearly defect-free hexagonal SiC (0001) wafers at temperatures up to 2000 °C . With ex−1at 0.3 K [RGaAs/AlGaAs – RGraphene)/(h/2e2) = (−4.7 ± 8.6)×10−11.The observation of the QHE at room temperature in graphene has attracted intense interest in physics and metrology communities , 10. In at 0.3 K . In 20112 V−1 s−1 to 40 m2 V−1 s−1 for quantised resistance plateaus of width 1 T to 2 T [2 V−1 s−1 to 0.7 m2 V−1 s−1 could provide quantised i = 2 plateaus which can extend from low magnetic flux densities of B ≈ 2 T to very high values of B ⩾ 15 T with proper control of the carrier concentration. Several papers from the NPL collaboration have attributed this plateau-broadening effect to charge transfer at the substrate/graphene interface, which extends the range of the plateau to very high magnetic field [Specialized molecular-beam epitaxy (MBE) systems had been necessary for the growth of GaAs/AlGaAs heterostructures having mobilities of 15 mT to 2 T . The staic field , 14. Bot2.2C, SiC2) by reducing their mean free path length compared to vacuum. This creates a near-equilibrium growth environment with higher partial pressures near the surface, which reduces the defect density in the graphene layer significantly [3H8) in an Ar/H2 ambient  can reveal the SiC terraces, however the identification of EG domains is far from straight-forward using AFM alone. Confocal laser scanning microscopy (CLSM)  and opti−1 that can be fitted by a single Lorentzian. In addition, the full-width-half-maximum (FWHM) of the 2D(G’) peak is broadened by stress and defects [−1 ± 1.4 cm−1 and a peak position of 2723.3 cm−1 ± 1.8 cm−1, produced using the combined methods of FTG and PASG as inhibitors of growth. In comparison, graphene epitaxy on SiC by CVD has a lower peak position around 2695 cm−1 [Raman spectroscopy is a fast and non-destructive tool to identify monolayer graphene, whose fingerprint in the Raman spectrum is a symmetric G’ peak (2D band) at ≈ 2700 cm defects –41. The 695 cm−1 , 43. Thi695 cm−1 .2.2.ρxy = h/2e2, h/6e2, …). While the i = 6 plateau is usually not visible in the case of low charge carrier density devices, the i = 2 plateau is exceptionally broad as shown in . i = 4 and i = 2 plateaus have sufficiently low dissipation to yield the precise quantization needed for resistance metrology, but the specific fabrication processes can be tuned to meet the requirements for quantised Hall resistance standards [In semiconductor quantum Hall systems, the plateaus in n doping , which atandards , 52.i = 2 plateau appears below 5 T, as shown in National metrology institutes have adopted several methods to control the transport properties of EG to compensate for excess electron doping from the covalent BL bonds such that the n-type conductivity. For lower charge carrier densities of |n| < 1 × 1011 cm−2 (grey shade) the critical current drops significantly as electron/hole puddles appear, while for |n| > 3 × 1011 cm−2 (white region) the resistance plateau is shifted to relatively high magnetic flux densities. The green shade region indicates the region of interest (ROI) for resistance metrology with 1 × 1011 cm−2 ⩽ |n| ⩽ 3 × 1011 cm−2 and a typical room temperature sheet resistance of 6 kΩ ⩽ RSH ⩽ 8 kΩ.Many of the difficulties that affect semiconductor hetero-structure QHR devices have analogs for epitaxial graphene and graphene devices in general. One example is the requirement for metallic ohmic contacts with a low and stable contact resistance , 58. The3.ELL forming the i = 2 plateau for single-layer graphene (1LG) [kBT. The large energy splitting is a result of the square-root magnetic field dependence and causes a rapid widening of the energy gap forming the RK/2 resistance plateau even at low values of B. If the ratio ΔELL/kBT ≈ 150 of typical GaAs-based resistance standards operating at a temperature of 1.4 K and B ≈ 10 T is taken as the reference value, one can expect much lower magnetic flux densities and higher temperatures for the measurements when using graphene [ne (1LG) , 64 and ne (1LG)  with resgraphene .nLL = 0 and nLL = 1 forming the i = 2 resistance plateau in graphene as a function of the Fermi energy EF [w are isolated from each other  or by the interaction with the substrate, which both cause strain that can create effective inhomogeneous magnetic fields . Intriguet al  and Katsl [et al . Predictet al [ρxy equal to h/2e2 to within 15 μΩ Ω−1 using a 1 mm wide exfoliated graphene device, limited by low breakdown current (⩽2.5 μA) and excess contact resistance. −9. There are also additional published measurements (not shown in the diagram) that demonstrate that GaAs/AlGaAs may also be used at significantly higher currents [The 2008 report ‘Quantum Resistance Metrology in Graphene’, Giesbers, Rietveld et al  describecurrents  or lowercurrents . However4.et al operates using an EG device at 5 T, 2.8 K to 3.0 K, and source-drain current ISD ≈ 100 μA, where measurements can provide relative uncertainty below 10−8 [As efforts in production of EG for electrical resistance metrology continue to move forward, NMI groups have envisioned several goals for the new standard. Presently, NMI resistance scaling with QHR is mainly realized at low bridge voltages of 0.5 V–1 V using room temperature direct current comparator (DCC) and cryogenic current comparator (CCC) bridges. Compact measurement systems using cryogen-free table-top cryostats could provide turn-key resistance traceability and significantly reduce the costs due the relaxed measurement conditions provided by graphene-based Hall devices , 77, 78.low 10−8 .qRK-90 where q is a positive rational number. However, in larger networks, an increasing influence of the contact resist ance and localized inhomogeneous carrier concentration may limit the precision of resistance quantization. The exceptional suitability of EG for this purpose is due to the pinning of the Hall resistance i = 2 plateau over a very wide range of magn etic flux densities [The future chain of traceability would benefit by utilizing higher voltages or currents, allowing full compatibility between EG quantum Hall devices and cryogen-free measurements. These development efforts focus on improving the accessibility of quantum resistance standards to the international community of NMIs and industry. One approach is the scaling to other quantised values by using QHE devices in series and parallel connections  or by p-ensities , 14 as wensities  would en−1 [The symmetric energy spectrum of graphene supports conductivity using both holes and electrons in the same device through gating or doping techniques. This is achieved by integrating several Hall elements in one device using alternating p-conducting and n-conducting graphene regions, thus reducing the complexity of network connections . Electri−1 . These r−1 .h and e. Moreover, NMI research on the QHR with alternating current (ac) opened new routes that enable connecting the ohm to other units such as the farad and henry by natural constants [The major reason for the success of the QHR with direct current (dc) for the realization of the unit ohm is its high robustness and its universality due to its direct relation to the natural constants onstants , 85. Comonstants –88.In conclusion, as the new SI is implemented in the coming year, EG devices exhibiting the QHE can provide a robust avenue to electrical resistance standards and metrology in general. The current efforts have shown great promise in being able to provide a smooth transition from the use of burdensome infrastructure found with GaAs-based QHR systems to the operation of user-friendly cryocooler systems in many labs.


In river-lake systems, sediment and water column are two distinct habitats harboring different bacterial communities which play a crucial role in biogeochemical processes. In this study, we employed Phylogenetic Investigation of Communities by Reconstruction of Unobserved States to assess the potential functions and functional redundancy of the bacterial communities in sediment and water in a eutrophic river-lake ecosystem, Poyang Lake in China. Bacterial communities in sediment and water had distinct potential functions of carbon, nitrogen, and sulfur metabolisms as well as phosphorus cycle, while the differences between rivers and the lake were inconspicuous. Bacterial communities in sediment had a higher relative abundance of genes associated with carbohydrate metabolism, carbon fixation pathways in prokaryotes, methane metabolism, anammox, nitrogen fixation, and dissimilatory sulfate reduction than that of water column. Bacterial communities in water column were higher in lipid metabolism, assimilatory nitrate reduction, dissimilatory nitrate reduction, phosphonate degradation, and assimilatory sulfate reduction than that of sediment bacterial communities. Furthermore, the variations in functional composition were closely associated to the variations in taxonomic composition in both habitats. In general, the bacterial communities in water column had a lower functional redundancy than in sediment. Moreover, comparing to the overall functions, bacterial communities had a lower functional redundancy of nitrogen metabolism and phosphorus cycle in water column and lower functional redundancy of nitrogen metabolism in sediment. Distance-based redundancy analysis and mantel test revealed close correlations between nutrient factors and functional compositions. The results suggested that bacterial communities in this eutrophic river-lake system of Poyang Lake were vulnerable to nutrient perturbations, especially the bacterial communities in water column. The results enriched our understanding of the bacterial communities and major biogeochemical processes in the eutrophic river-lake ecosystems. Lakes and their tributaries are highly linked ecosystems in multiple ways, especially through materials transported from the watershed to the lake through river systems . MicrobiIn aquatic ecosystems, bacterial communities play an extremely important role in transformation, accumulation, and migration of nutrients and other elements, as well as in energy conversion and material recycling . BacteriChanges in water quality and sediment properties drive the variation of bacterial communities which regulate the core biogeochemical processes such as carbon and nitrogen metabolisms in aquatic ecosystems . As the 2 (in summer), it is the largest freshwater lake in China. There are five rivers  feeding Poyang Lake and one outlet connecting to Yangtze River , ammonium (NH4+), total phosphorus (TP), and soluble reactive phosphorus (SRP) were analyzed according to the Clean Water Act Analytical Methods . TP was analyzed using alkali fusion-Mo-Sb Anti spectrophotometric method (HJ632-2011). Total organic carbon (OC) was analyzed using Potassium dichromate oxidation spectrophotometric method (HJ615-2011). Organic nitrogen was analyzed using acid hydrolysis method , nitrate (NO Methods . DOC was Methods . For seds method . Organics method .DNA was extracted from the filter and sediment (0.5 g) samples using the TIANGEN-DP336 soil DNA Kit  following manufacturer protocols. Extracted DNA samples were quantified using a Qubit 2.0 Fluorometer . The V3 and V4 regions were amplified using the forward primer 347F 5′-CCTACGGRRBGCASCAGKVRVGAAT-3′ and the reverse primer 802R 5′-GGACTACNVGGGTWTCTAATCC-3′  . PCR wasPRJNA436872, SRP133903).Raw sequence data was processed using the software package QIIME 1.9.1 . The forP-values were adjusted by FDR correction. Linear regression was used to assess the relationships between taxonomic and functional dissimilarities, revealing functional redundancy of the bacterial communities   between the bacterial communities in different habitats of the river-lake ecosystem of Poyang Lake, non-metric multidimensional scaling (NMDS) and analysis of variance using distance matrices (ADONIS) were applied using the Vegan package 2.4–6  based onundancy) . Taxonom R 3.4.4 .P < 0.05) different to LW and RW (LS vs. LW and RS vs. RW), respectively  were closely associated with the variations in phylogenetic composition . HoweverIn this study, the functional composition of bacterial communities in the river-lake system of Poyang Lake were different between water and sediment (LS vs. LW and RS vs. RW), while no different between tributaries and the lake itself (LS vs. RS and LW vs. RW). In our previous study of the river-lake system of Poyang Lake , bacteriThis study showed that carbohydrate metabolism, carbon fixation pathways in prokaryotes, and methane metabolism had a higher relative abundance in the bacterial communities in sediment than in water, and the lipid metabolism had a higher relative abundance in water than in sediment. The results suggested that bacterial communities in sediment and water had distinct carbon metabolism pathways. Organic matter (OM) transported by river provides fueling aquatic food webs as a major source of energy and is also a significant component of the global carbon cycle . In fres3− and OC, as well as redox potential  in water might be performed through aerobic denitrification with the facilitation of high supplement of OM and NO3−. In addition to denitrification, bacterial communities in sediment had a significantly higher relative abundance of the genes associated to anammox than in water. It was found that anammox can coupled to nitrate reduction to contribute substantially to produce dinitrogen in sediments , suggesting that the overall changes in potential functions, as well as the changes of potential metabolisms of C, N, P, and S were closely associated with changes in taxonomic compositions of the bacterial communities. Functional redundancy always exists in natural ecosystems  and is mIn this study, we assessed the functional properties of bacterial communities in SL, SR, WL, and WR in the river-lake system of Poyang Lake. In general, the results showed that bacterial communities in sediment and water had distinct potential functions in the biogeochemical processes of carbon, nitrogen, phosphorus, and sulfur. However, there was no difference between tributaries and the lake itself. Moreover, bacterial communities in water column had a lower functional redundancy than in sediment. Comparing to the overall functions within systems, bacterial communities had lower functional redundancy of nitrogen metabolism in sediment, and lower functional redundancy of nitrogen metabolism and phosphorus cycle in water column. In this eutrophic river-lake system, functional compositions of the bacterial communities were vulnerable to nutrient perturbations especially in water column. By revealing the metabolism pathways of major functions, the influences of nutrient variables on functional compositions, and functional redundancy, this study can provide insights into the microbial community structures and ecological processes in this river-lake system.10.7717/peerj.7318/supp-1Supplemental Information 1Click here for additional data file.


Graphene plasmonic antennas possess two significant features that render them appealing for short-range wireless communications, notably, inherent tunability and miniaturization due to the unique frequency dispersion of graphene and its support for surface plasmon waves in the terahertz band. In this letter, dipole-like antennas using few-layer graphene are proposed to achieve a better trade-off between miniaturization and radiation efficiency than current monolayer graphene antennas. The characteristics of few-layer graphene antennas are evaluated and then compared with those of antennas based on monolayer graphene and graphene stacks, which could also provide such improvements. To this end, first, the propagation properties of one-dimensional and two-dimensional plasmonic waveguides based on the aforementioned graphene structures are obtained by transfer matrix theory and finite-element simulation, respectively. Second, the antennas are investigated as three-dimensional structures using a full-wave solver. Results show that the highest radiation efficiency among the compared designs is achieved with the few-layer graphene, while the highest miniaturization is obtained with the even mode of the graphene stack antenna. Terahertz band communication is a key wireless technology that enables a plethora of applications at the macroscale and micro/nanoscale ,2. This Different graphene plasmonic antenna designs have been investigated in the literature, often highlighting the abovementioned significant advantages over conventional antennas, which are given by the unique frequency dispersion of graphene and its ability to support surface plasmon polaritons (SPPs) in the terahertz band ,5,6,7,8.In this paper, we investigate the use of few-layer graphene in plasmonic antennas with the aim of obtaining a graceful balance between efficiency and miniaturization. Particularly, we evaluate the radiation efficiency, miniaturization, and impedance characteristics of dipole-like antennas based on few-layer graphene for a wide set of parameter values and compare them to those of a monolayer counterpart. For a more complete comparison, we also consider graphene stacks as they can also provide high radiation efficiency and miniaturization thanks to their mode coupling and field confinement potential.l and width w, as depicted in 2O3) in our case. In the graphene stack case, a polymethylmethacrylate (PMMA) layer is used to act as a dielectric between the two graphene sheets. The substrate is considered high resistivity Gallium Arsenide (GaAs). To bring the design closer to experimental realization, we assume the dipole to be fed at its center gap of length g with a terahertz photomixer that acts as a photoconductive source [The antenna under study is basically a dipole of total length e source ,13.The remainder of the paper is as follows. In 2O3-MLG-Air, GaAs-Al2O3-FLG-Air, and GaAs-Al2O3-GS-Air.In order to design and analyze an efficient plasmonic antenna, the investigation of the surface plasmon mode supported by its guided-wave structure is a primary step. Simplification of two-dimensional structures to one-dimensional structures is a reasonable starting point for their analysis. Therefore, consider three slab waveguides composed of monolayer graphene (MLG), few-layer graphene (FLG), and graphene stack (GS) as shown in N is the number of layers. The reason for defining FLG for Although there is not a definitive consensus on the definition of FLG, most works consider it to be graphene sheets with no more than five layers ,13,14. T formula  and N is2O3, and PMMA are assumed 12.9, 9, and 2.4, respectively. The layer thickness of both Al2O3 and PMMA are assumed 100 nm, well within fabrication limits [In the case of GS, two graphene monolayers are separated by PMMA dielectric with height  effects . DielectThe transverse magnetic (TM) modes supported by the SPP waves for the waveguides are studied using the formulations of transfer matrix theory provided in our previous work . It is wBased on previous experiments and compatible with existing growth, encapsulation, and biasing techniques ,12,14, wThese results regarding the behavior of plasmonic guided-wave structures can be employed to reason about the performance of graphene antennas as follows. In order to compare the miniaturization potential of the different antennas, the On the other hand, a suitable qualitative measure of superiority of the structures from the perspective of radiation efficiency is the Let us now return to the two-dimensional guided-wave structure. We used the finite element method of the COMSOL field solver to perform the numerical calculations, including normal electric fields and effective refractive indices The antennas made of three kinds of guided-wave structures  are investigated as three-dimensional structures by the full-wave solver of the software CST Studio Suite.l = 12 μm and w = 3–5 μm, the real and imaginary parts of the input impedance of a MLG-based antenna are as shown in l = 12 μm, w = 3 μm, g = 2 μm, τ = 0.6 ps, and Assuming structural parameters of In order to study the antennas based on FLG structure and compare them with antenna based on MLG structure, we present radiation efficiency w, which provides a larger electrically antenna, both result in a higher radiation efficiency.In both structures, changing chemical potentials from 0.5 to 0.9 eV causes the Higher confinement by the use of a narrower strip or lower Fermi level increases the value of the input impedance. Moreover, higher Results also confirm that the FLG5 has higher radiation efficiency and lower miniaturization than MLG-based antennas. This is because the guided-wave structure based on FLG5 provides a mode propagating with a lower loss and a lower confinement compared to MLG structure. Since the conductivity of FLG5 starts to be comparable to that of bulk graphite, we do not expect that adding more layers would result in significant improvements. In any case, efficiency would increase slightly and miniaturization would drop.Let us now compare the antenna based on FLG (only FLG2 with two layers for the sake of brevity), GS with different This paper has proposed few-layer graphene as a promising material for the realization of THz reconfigurable high radiation efficiency plasmonic antenna. The choice is driven by its higher conductivity with respect to monolayer graphene. Through analytical and numerical methods, we confirmed that few-layer graphene antennas offer high efficiency at the cost of losing some miniaturization potential. It has been also observed that the choice of number of layers allows to navigate the efficiency–miniaturization tradeoff. A comprehensive comparison to graphene stacks, which are a valid alternative with potential for low losses and high confinement, has further confirmed that the highest radiation efficiency is achieved by the few-layer graphene structure, while the highest miniaturization is supported by the even mode of graphene stack structure.


In the present work, we performed nanoindentation tests using molecular dynamics (MD) simulations on graphene, native silica aerogels, and single- and multi-layered graphene-reinforced silica aerogel nanocomposites. This work mainly focused on the two aspects of nanoindentation simulations: first, the resultant indentation force–depth curves, and second, the associated mechanical deformation behavior. We found that in the single-layer graphene-reinforced silica aerogel nanocomposite, the indentation resistance was four-fold that of native silica aerogels. Moreover, the combined system proved to be higher in stiffness compared to the individual material. Furthermore, the indentation resistance was increased significantly as we proceeded from single- to two-layered graphene-reinforced silica aerogel nanocomposites. The results of the study provide a detailed understanding of the mechanical behavior during the indentation tests of nanocomposites, which helps to design advanced nanoscale multi-layered materials. The structure of silica aerogel is a three-dimensional open-cell nanoporous network whose skeleton is composed of interconnected silica nanoparticles . Due to Therefore, several approaches have been proposed in the literature to improve the mechanical properties of silica aerogel, e.g., chemically modifying the aerogels via integration of organic coatings, organic crosslinking of the backbone or using organically-modified silica precursors ,7. HowevComputational modeling has not been used extensively to explore many aspects of silica aerogels. However, in the last decade, there has been a rising interest in MD simulations, which have been used to describe the mechanical properties of native silica aerogels ,20,21,22In the past three decades, nanoindentation experiments have been predominantly used to study the elastic and inelastic behavior of several porous materials. In particular, these experiments allow the measurement of physical properties such as Young’s modulus, hardness, and the elastic properties of heterogeneous nanomaterials with high spatial resolution  . In the aerogels .In this work, we aim to elucidate the mechanical properties of graphene, native silica aerogels, and graphene-reinforced silica aerogel nanocomposites during nanoindentation tests using MD simulations. In particular, we focused on indentation force–depth curves to compare the influence of graphene reinforcement on silica aerogel.In this work, all MD simulations of the nanoindentation were performed using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) . For visA detailed description of the creation of the atomistic silica aerogel models has been discussed in our previous work . Here, trdinates . InitialThe expanded sample was then heated to 3000 K for 50 ps, where the MD system was given the opportunity to overcome energetic barriers in the search for conformations with energies, followed by relaxation. Finally, the sample was quenched to 0 K followed by the energy minimization. The nanoporous silica aerogel was formed when the sample was further brought back to the atmospheric conditions. The heat treatments in the simulations were performed using the NVT (constant volume and constant temperature) ensemble except for the relaxation, which was carried out using the NPT  ensemble. The nanoindentation tests were carried out on the equilibrated systems.The separated distance between two atoms was computed using the radial distribution function (RDF) or terature ,20,33. AIn this work, we mainly focused on the deformation mechanisms of highly-nanoporous silica aerogels and nanocomposites of them under indentation at the nanoscale. For the reinforcement, we used graphene sheets in silica aerogels. For MD simulations of graphene, the short-range interactions between the C–C atoms was defined by Brenner’s second-generation reactive empirical bond-order (REBO) force field , while tv of 1 Å/ps in the z-axis direction.In the graphene-reinforced nanocomposite simulation systems, graphene sheets were modeled on and in between the silica aerogels. Therefore, it was crucial to define the interatomic potential between Si, O, and C atoms. As discussed earlier, for the silica atoms ,34 and tAfter the whole indentation system had been set up, the Maxwell–Boltzmann distribution was used to assigned the initial velocities and then followed by energy minimization . SubsequThe primary goal of this study is to investigate the influence of graphene reinforcement on the mechanical properties of silica aerogel using nanoindentation. MD simulations of native silica aerogel and single and multi-layered graphene systems were carried out. Moreover, in multi-layered graphene-reinforced systems, two types of silica aerogel slabs were considered. Finally, the results of all the MD simulations are presented and compared.h) and the associated indenter force (P) were recorded, and the averaged curve is shown in Graphene is the highest stiffness and strength material known to man ; therefoh> 90.1 Å), the fractured portion of carbon atoms tried to make connections with an unfractured graphene sheet. Therefore, even after the fracture, there was a significant amount of resistance offered from the sheet. In the indentation simulations of the graphene sheet, the fracture occurred in the graphene sheet at a depth of 90.1 Å, and the maximum force was reached at 1229 nN.The distance between the indenter tip and the top surface of the native silica aerogel of density ent work .P – h curve with the standard error deviation. To avoid the model-dependent P – h curve, independently, nanoindentation tests were performed on six faces of the silica aerogel block. For the maximum penetration of 90 Å, the maximum recorded force was 443 ± 58 nN. From the nature of the curve, it can be observed that the MD models showed a high plastic energy dissipation, which was nearly 97–98%. Therefore, there was nearly no recovery observed, which is demonstrated in To investigate the impact of graphene reinforcement on the mechanical properties, the MD model was constructed with a single layer of a graphene sheet on top of the native silica aerogel (1G-SiOh = 90.1 Å. However, for a 1G-SiOh reached 90 Å. This occurred due to the out-of-plane flexibility of the graphene sheet, which was restricted by the deformed aerogel. Upon unloading, the permanent deformation of the fractured graphene sheet and the silica aerogel was observed.During loading, the graphene sheet transferred the indentation load to the aerogel. In the case of a single graphene sheet, the fracture occurred at P – h relation of graphene-reinforced silica aerogel with the response of the single graphene sheet and that of native silica aerogel. The averaged maximum indentation forces for the graphene and the native silica aerogel were 1229 and 443 nN, respectively. For the 1G-SiOTo study the mechanical performance of the nanocomposites, mainly two thicknesses of slabs of the silica aerogel were modeled. To investigate the influence of multi-layered reinforcement accurately, the native silica aerogel model was kept at the base, and additional layers and slabs continued to be added. The Type I and II silica aerogel slabs represent the different thicknesses of 50.4 and 126.3 Å, respectively. Each type was constructed with two layers (2G-1SL-SiOrmed see a. There rred see b. Here, In all simulations, as indentation progressed, the elastic deformation of the graphene sheets was observed; however, close to the indented area, below the graphene sheets, localized compression of silica aerogel was noticed. Although the interactions between the graphene and aerogel distributed the concentrated force exerted by the indenter on a considerably larger area, the localized compression of silica aerogel was significant. This localized area turned into local densification of the silica aerogel, which restricted the further elastic deformation of the graphene sheets and ultimately resulted in a fracture of the sheets. Interestingly, in the case of 2G-1SL-I-SiOIn this work, we have investigated the mechanical properties of a single graphene sheet, native silica aerogel, and multi-layered graphene-reinforced silica aerogel nanocomposites using MD simulations of nanoindentation tests.Graphene has proven to be an extraordinary reinforcing candidate for silica aerogels on the basis of the indentation force–depth predictions. For the single-layer graphene-reinforced silica aerogel nanocomposite, the indentation resistance was four-fold of the indentation resistance of a native silica aerogel. The nanocomposite system also showed a higher stiffness compared to the individual material. The maximum indentation force was increased significantly as we proceeded from a single- to two-layered graphene-reinforced silica aerogel nanocomposite. Moreover, the different thicknesses of silica aerogel slabs had no significant influence on the maximum indentation force.We studied here the multi-layered graphene reinforcement; therefore, the extension of this work is to distribute the graphene sheets randomly in silica aerogels and examine the influence of reinforcement. Furthermore, the popular reinforcement materials in silica aerogel, such as carbon nanofibers, carbon nanotubes, carbon aerogels, and graphene aerogels, will be studied using nanoindentation.


The triple-negative breast cancer (TNBC) is characterized by a more aggressive nature and poorer prognosis, nowadays none pharmaceutical approach is still available. For this reason, the research of new active compounds and attractive targets represents an interesting field. In this context MDA- MB-231 cell line was selected to evaluate the antiproliferative effects of new -pyrroloquinoxaline derivatives. The MTT assay revealed that the amine forms of synthesized molecules were more active compared to iminic ones at 72 h of incubation. The antiproliferative effect of the most promising compounds highlighted the formation of autophagic vacuoles. Breast cancer (BC) is a heterogeneous and complex disease and one of the leading causes of death in 40–59 years old women. An estimated 1 million cases of BC are diagnosed annually worldwide and of these, about 170,000 possess a triple negative (TNBC) phenotype  and the appropriate aldehyde (1.26 mmol) were mixed. After 5 min, 2-(1H-pyrrol-1-yl) aniline (1.26 mmol) was added. The resulting mixture was stirred for 30 min at room temperature. Then, the solvent was removed under reduced pressure. The residue was dissolved in ethyl acetate (50 mL) and extracted with a 5% aqueous solution of NaHCO3 (3 x 50 mL). The combined organic layers were made anhydrous with Mg2SO4, filtered and concentrated under reduced pressure. The pure compounds were obtained after purification with column chromatography using a mixture n-hexane: ethyl acetate as eluent.All reagents used in this synthesis, equipment, and spectroscopic data are reported in the 2 incubator at 37°C as recommended by ATCC. Cell viability was determined by measuring the reduction of 3--2, 4,- diphenyltetrazolium bromide (MTT) by mitochondrial succinate dehydrogenase. Briefly, cells were seeded at 1 × 104 and incubated with various concentrations of compounds L1-10 (1–20 μM) alone or with DMSO (as a vehicle) in 96-well plates for 24 and 72 h. The optical density (OD) was calculated as the difference between the absorbance at the reference wavelength (620 nm) and the absorbance at the test wavelength (570 nm). Percent viability was calculated as (OD of drug treated sample/OD of control) ×100.The human epithelial breast carcinoma MDA-MB-231 cells were purchased from the American Type Culture Collection (ATCC). Cells were cultured in Dulbecco's modified Eagle's medium (DMEM)  supplemented with 10% fetal bovine serum (FBS) (Invitrogen) and maintained in a humidified 5% CO5 MDA-MB-231 cells were grown on covers lip in 24-well plates and treated with L1, L5, and L6 at 20 μM at 72 h. Cells were fixed with 4% paraformaldehyde (ThermoScientific) and imaged using by a fluorescent microscope. At least tree visual fields were analyzed under fluorescence microscope (Leica FL560 fluorescence microscopy) for each sample.Changing in morphology for nuclei swelling or autophagic vacuoles formation were assessed by 4,6-diamidino-2-phenylindole (DAPI) or monodansylcadaverine (MDC) staining. 1 x 10p < 0.05 (*), p < 0.01 (**), p < 0.001 (***).Data were expressed as mean ± standard deviation from three independent experiments ran in triplicate. Statistical differences were determined by one-way analysis of variance (ANOVA) followed by Tukey's Multiple Comparison Test. Differences were considered statistically significant for L1-10  and -CH (5.10–5.20 ppm) of the aminic form. Complete spectroscopic data are reported in The synthesis of pirroloquinoxalines L1-10  was carrL1-10  that allL1-6 L8-10 for 24 or 72 h and then cell viability was assessed by MTT assay in vitro results indicate the impact of the different substituents on the anti-proliferative activity. As shown in L5, that is the aminic form of L6 with an indole substituent on C4 position, inhibited the cell proliferation at 24 h, whereas the other compounds were ineffective, out contrary L1, bearing a vanillic residue on C4, induced proliferation. On the other hand, at 72 h all the synthetic compounds highlighted a decrease of the proliferation rate, including L1 (L1, 5 and 6, resulted in a potent cytotoxicity effect which was able to induced nuclear swelling stained with DAPI 50 was calculated with GraphPad Prism 5.0 using the non-linear regression curve fit. To straight our observations L1,5,6 were tested on MDA-MB-468 cell line, pointing out a vitality decreasing of 36, 40, and 41% respectively.To determine whether the new derivatives provide the desired TNBC antiproliferative activity, MDA-MB-231 cell line, were exposed to several concentration of uding L1 . Particuin vitro results obtained in this study, it is possible to confirm the versatility of the pyrroloquinoxaline nucleus that once again showed interesting antiproliferative activity assessed with MTT assay. The decrease in vitality is due to the induction of autophagy in TNBC as it is evident by DAPI and MDC staining. In fact, this latter staining highlighted cells autophagic vacuoles formation after treatment with L1, 5, and 6 at 72 h. These three compounds show important chemical differences. Firstly, L1 presents a vanillic residue on C4 position, conversely to L5, 6, an aminic and iminic form respectively, that bearing both an indole nucleus, and in the case of L6 also with a bromine atom in position C7 of indole moiety. Vanillic and indole are both privileged natural scaffolds, able to confer important antiproliferative properties, that can work synergistically when are linked at a pyrroloquinoxaline nucleus, already consolidated building blocks for active and promising anticancer agents (Aiello et al., Autophagy is a self-eating behavior initiated by cells as a protective and pro-survival pathway against DNA damage as well as by metabolic and therapeutic stress. When excessive this process can lead to cell death in many type of cancers including breast (Perri et al., The raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher.FA and EC: conception and study design, manuscript preparation; MP: biological assays and results recording; LA, GC, and SM: bibliographic research, synthesis, and chemical characterization of new compounds; MC: critical reading and intellectual assessment of manuscript. All authors read and approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


In recent decades, microcapsules containing phase change materials (microPCMs) have been the center of much attention in the field of latent thermal energy storage. The aim of this work was to prepare and investigate the microstructure and thermal conductivity of microPCMs containing self-assembled graphene/organic hybrid shells. Paraffin was used as a phase change material, which was successfully microencapsulated by graphene and polymer forming hybrid composite shells. The physicochemical characters of microPCM samples were investigated including mean size, shell thickness, and chemical structure. Scanning electron microscope (SEM) results showed that the microPCMs were spherical particles and graphene enhanced the degree of smoothness of the shell surface. The existence of graphene in the shells was proved by using the methods of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). It was found that graphene hybrid shells were constructed by forces of electric charge absorption and long-molecular entanglement. MicroPCMs with graphene had a higher degradation temperature of 300 °C. Graphene greatly enhanced the thermal stability of microPCMs. The thermal conductivity tests indicated that the phase change temperature of microPCMs was regulated by the graphene additive because of enhancement of the thermal barrier of the hybrid shells. Differential scanning calorimetry (DSC) tests proved that the latent thermal energy capability of microPCMs had been improved with a higher heat conduction rate. In addition, infrared thermograph observations implied that the microPCMs had a sensitivity response to heat during the phase change cycling process because of the excellent thermal conductivity of graphene. The whole world is currently confronted with a global energy crisis in that the increasing world population is linked with a large increasing energy demand. One of the effective ways to reduce energy demands is the use of thermal energy storage . DependiA literature review shows that microPCMs have been widely studied including the fabrication process, microstructure control, mechanical properties, and latent heat storage properties . Less at3 enhanced the thermal conductivity of microPCMs. In spite of such promising characteristics, there exists rare reportage in the literature addressing the use of this method for improving thermal conductivity.Another approach is to enhance the thermal conductivity of polymeric shell materials through nano-filler additives . More pr2/g [3. It was reported that graphene nano-platelets were dispersed in liquid eicosane at various loadings of 0–10 wt %. The thermal conductivity enhancement was above 400% for the highest loading of 10 wt %, whereas the latent heat of the PCM composite correspondingly decreased by 16% [Graphene, as a 2D carbon material, has a superior thermal conductivity of 5000 W/(m∙K) and a high specific surface area of 2630 m2/g . It is a2/g  preparedd by 16% . As showd by 16%  fabricatd by 16% .Nowadays, graphene nano-sheets are famous for their outstanding properties such as high thermal conductivity and ultra-low electrical resistivity. The most popular route for the bulk production of graphene sheet is the chemical oxidation and exfoliation of graphite, followed by reduction. Interestingly, the low density of graphene sheets is another advantage for making it a good choice to modify the microcapsules ,19,20. H3, Tianjin Kemel Chem. Co., Ltd., Tianjin, China). Methanol modified melamine-formaldehyde (MMF) prepolymer  was used as the polymer shell material with solid content of 78.0%. Styrene maleic anhydride (SMA) copolymer  was applied as a dispersant. Graphene was supplied by Huifeng Co., Ltd. . All other chemicals, unless otherwise stated, were obtained from commercial sources and used as received.Paraffin was used as the PCM material (0.889 g/cm−1. The temperature was increased to 80 °C with a rate of 2 °C·min−1. (c) After polymerization for 1 h, the temperature was decreased slowly to ambient temperature. Finally, the resultant microcapsules were filtered and washed with pure water and dried in a vacuum oven.The microPCMs were prepared by a self-assembled graphene/organic hybrid polymerization method. In details, the whole process can be divided into three steps: (a) SMA (2 g) was added to 100 mL water at 50 °C and allowed to mix for 2 h. Then a solution of NaOH (10 wt %) was added dropwise adjusting its pH value to 10. The above surfactant solution and paraffin (50 g) were emulsified mechanically with a vigorous stirring rate for 10 min using a high-speed disperse machine. (b) The encapsulation was carried out in a 500 mL three-neck round-bottomed flask equipped with a condenser and a tetrafluoroethylene mechanical stirrer. The above emulsion was transferred to the bottle, which was dipped in a steady temperature flume (room temperature). The mixture of MMF prepolymer (25 g) and various contents of graphene were added dropwise with a stirring speed of 500 r·minOptical photographs of the microPCMs retained in the emulsion were taken by an optical microscope . The surface morphologies of dried microPCMs were observed by using a Scanning Electron Microscope  at an accelerated voltage of 15 kV. The mean size of microPCMs was measured using a partial diameter distribution machine . The measurement method of shell thickness was applied in previous work . About 1−1 with a resolution of 4 cm−1, and 128 scans were averaged for each sample.Fourier-Transform infrared (FTIR) spectra of dried films were obtained using a Nicolet Magna 750 spectrometer with a deuterated triglycine sulfate detector and Omnic 3.2 s software. Scanning was carried out in the range 4000–400 cmA transmission electron microscope  was utilized to observe the graphene on the surface of microPCMs. Atomic force microscopy (AFM) examination was carried out for each microcapsule sample in the tapping mode with a NanoScope V AFM  . The ele−1 in a flow of 40 mL·min−1 nitrogen (N2). Another method was adopted to evaluate the thermal stability of microPCMs by a thermal absorbing-releasing process using a temperature-controlled chest [−1 and kept for 10 min, and then the temperature decreased to −10 °C·min−1 with the same rate of 2 °C·min−1. This heat absorbing-releasing process for each sample was repeated for 50, 100, 150, and 200 cycles. The final states of microPCMs were observed by SEM to analyze their thermal stability.The thermal stability characterization of microPCMs was performed on a Dupont SDT-2960 thermogravimetric analysis (TGA) at a scanning rate of 5 °C·mined chest . The sam. The tests were in accordance with ASTM E-1530 standard. A powder sample (20 g) was held under a uniform compressive load between two polished surfaces, each controlled at a different temperature. The lower surface was part of a calibrated heat flow transducer. The heat flowed from the upper surface, through the sample, to the lower surface, establishing an axial temperature gradient in the stack. After reaching thermal equilibrium, the temperature difference across the sample was measured along with the output from the heat flow transducer. These values and the sample thickness were then used to calculate the thermal conductivity. The temperature drop through the sample was measured with temperature sensors in the highly conductive metal surface layers on either side of the sample. For one-dimensional thermal conduction the formula can be given as Equation (1),Q is the heat flux (W), λ is the thermal conductivity (W/(m·K)), A is the cross section area (m2), x is the thickness of the composite sample (m). The Q value is the average of three tests under the same conditions.The thermal conductivity values of microPCMs samples were measured using a thermal conductivity instrument An infrared thermograph  was applied to measure the thermal transmission of various microPCMs with graphene. Each microPCMs sample (5 g) was put on a constant temperature heating plate with a temperature of 100 °C in 60 s. The spectrum and amount of thermal radiation depend strongly on an object’s surface temperature. This makes it possible for a thermal imaging camera to display the surface temperature of a microPCMs sample. The radiation depends not only on the temperature of the environment, but is also a function of the emissivity of the microPCMs. The emissivity (e) was set to 0.9. The thermal conductivity values of microPCMs samples with various graphene contents were discussed by comparing the infrared thermographs.−1 between the range of −20 to 50 °C under nitrogen (N2) atmosphere. The encapsulation efficiency of the core material content was measured from the heat of fusion (ΔHf) of PCM [rE) is by Equation (2),The thermal analyses of microPCMs were measured by a Perkin-Elmer Diamond DSC (USA) at a heating rate of 5 °C·min) of PCM . The met2OH, which dissolve with negative charge in an acid aqueous solution combining with hydrogen ions. Therefore, prepolymer can be absorbed onto the droplet surfaces by electrostatic interaction  is widely applied to prepare various functional microcapsule products due to its low price, easy technology, high compactness, fire resistance, and chemical resistance . Howevereraction c. Intereeraction d. The sheraction e.The above self-assembled mechanism of graphene hybrid shells already has been proved in previous work . In orde−1. Five typical microPCMs samples were prepared with different graphene/MMF percentage of 0%, 2.0%, 4.0%, 6.0%, and 8.0%, which are coded as MG-0, MG-2, MG-4, MG-6, and MG-8, respectively. As all microPCMs samples were fabricated under the same emulsion rate, it was considered that they had the same mean size. For the inorganic/organic hybrid microcapsules, the additive of the nanoparticles can greatly influence the morphologies of the shells. For example, Su [3 nanoparticles adhering on the shells. In this work, more morphology details of the shells can be observed from the SEM morphologies of the microcapsule samples  with various graphene contents. Microcapsules (GM-0) have a global shape without a break  are shown in ll ratio ,16. With3) groups. The further cross-linking reactions of the oligomer form the stable shells of the microcapsules. The crosslinked MMF network provides a protective barrier between the core material and the external environment preventing core material leakage or contamination. The marked FT-IR spectra belong to (b) paraffin, (c–e) microPCMs samples . The spectrum of paraffin (b) exhibits the characteristic absorption bands at around 1461 cm−1 and 2924 cm−1 attributed to –CH3 asymmetric bending vibration and alkyl –CH2 stretching vibration. The spectra of all microcapsule samples  exhibit three absorption bands at around 1653 (C–C), 3115 (N–H) and 3618 cm−1 (O–H). The characteristic peaks of the paraffin no longer exist, which indicates that the paraffin has been totally microencapsulated. The spectra also imply that microcapsule samples have different graphene contents in the shells. Based on the intensity of absorption peaks, it was found that both samples have O–H bonds, which may belong to the residual water. More graphene in the shells does not change the chemical structure of the graphene/MMF composites. In other words, the graphene has a physical bond with crosslinked MMF networks.MMF prepolymer has a crosslinked chemical reaction in the emulsion state to yield a compactable shell structure. The prepolymer interaction generated oligomer is shown in In previous work, it was confirmed that graphene can exist in the shells of microcapsules . HoweverMore information about the graphene/MMF hybrid microstructure of shells can be found in the AFM morphologies of a single microcapsule surface with/without graphene. GM-0 sample has a relatively rough shell a. For GMIn order to further verify the contents of graphene in shells, XPS spectra were analyzed to give more structure details on the carbon element in the microcapsule shells. TGA curves were analyzed to study the thermal stability of pure paraffin and the microPCMs samples  as shown in In order to understand more details of the thermal states of the microcapsules, the surface morphologies of the microcapsules were observed after suffering a high temperature process for 10 min. −1 and maintained for 10 min, and then the temperature decreased to −10 °C·min−1 with a rate of 2 °C·min−1. This thermal treatment cycle for each sample was repeated for 50, 100, 150, and 200 times. 1–a4) shows the SEM morphologies microPCMs (MG-0) after 50, 100, 150, and 200 cycles, respectively. Before 100 cycles, the microcapsules still kept a compact structure. However, a lot of the microcapsules were broken after 200 cycles without resisting the heat treatment. Comparatively, MG-2 particles survived after 200 cycles 1–b4). Only a few microcapsules had holes on the shells. This conclusion implies that the microcapsules with graphene have good thermal stability when suffering a violent temperature change. 1–c4) and 1–d4) show the SEM morphologies of microPCMs (GM-4 and GM-6) after 50, 100, 150, and 200 cycles, respectively. All microcapsules from beginning to end, maintain the global shape without breaking. Graphene in the shell can dramatically help to resist the temperature changes avoiding the rupture of the shells.Another method was designed to test the thermal stability of microPCMs under heat absorbing-releasing cycles using a temperature-controlled chest. The samples were heated to 50 °C with a rate of 2 °C·minIn this study, the microPCM samples with graphene were expected to retain remarkable thermal conductivity, which gives the microcapsules a faster heat absorbing-releasing capability during thermal exchange. The thermal conductivity values of five samples  were measured to investigate the influence of the graphene amounts . First, IRT has been widely applied to measure the radiant thermal energy distribution and heat conduction behavior emitting from a target. For example, this technology is employed to complete the non-destructive evaluation or non-destructive devaluation applied to composite structures . Furthere) value of 0.9, which is noted on top of each image. The reason is that the MMF polymer usually possesses an e value between 0.90 and 0.98 [10–a60)). Comparatively, MG-0 has a color transformation from green to red in 60 s. Its temperature also has risen from 25.0 °C to 35.8 °C (10–b60)). This phenomenon indicates that only 1.0 wt % graphene in the shell material can evidently enhance the thermal conductivity of the microPCMs particles. This trend also appeared in IR images of other microPCMs samples. The final temperatures at the end of 60 s of these samples are 70.7 °C (10–c60)), 76.5 °C (10–d60)), 85.6 (10–e60)), 89.3 °C (10–f60)) and 96.7 °C (10–g60)), which is a sharp increase of temperature. It means that microPCM samples have a dramatic enhancement of thermal conductivity with increasing graphene contents in the shells. This conclusion also can be drawn from the temperature data at 10 s for these samples. In images  after only a short time, the samples changed to 33.5 °C, 37.7 °C, 53.8 °C, 58.8 °C, 61.2 °C and 62.7 °C. These results are at the same time consistent with the above analysis of the data of direct measurements for thermal conductivity.and 0.98 . Becauseand 0.98 . TherefoTm) is about 20.2 °C similar to the Tm of pure paraffin. It means that the polymeric material shells do not greatly influence the phase change behavior of paraffin. With the addition of graphene in the shells, microPCM samples of MG-2, MG-4, and MG-6 have Tm values of 18.4 °C, 16.2 °C and 10.5 °C, respectively. These temperatures are even lower than the Tm value of pure paraffin. With the increasing of graphene content in the shells, the Tm values of the microPCM samples  decreased sharply. These phenomena imply that the graphene has dramatically enhanced the thermal sensitivity of the microencapsulated paraffin. Heat will rapidly transfer through the graphene composite shells with pure paraffin inside. Because the microcapsules have a large specific surface area, paraffin can absorb more thermal energy with less thermal resistance. Graphene can greatly enhance the smoothness of heat transfer at the same time through a heat channel formed by overlapping graphene. The slopes of the DSC curves increased with the more graphene added in the shells during the melting process of the phase change. Meanwhile, the intervals of the phase transition temperatures became narrower. All these results indicate that the addition of graphene can significantly enhance the heat transfer efficiency. In addition, the solidification temperatures of MG-2, MG-4, and MG-6  decreased compared to MG-2 (−1.2 °C) without graphene. This proves in a further way that the graphene can improve the thermal sensitivity of microPCM samples.DSC tests were carried out to analyze the thermal energy storage capacity of the microPCM samples in terms of melting/solidifying temperatures and latent heat capacity. Hm) and solidifying energy (ΔHs) are listed in Hm values of 132.5, 145.2, 155.7, 160.5 J/g, and their ΔHs values are 120.5, 138.5, 149.8, 158.7 J/g, respectively. With the graphene content increasing in the shells, the microPCM samples have an obvious enhancement of latent thermal energy storage capability. This conclusion is consistent with the analysis of the above DSC curves. The ratio relationship expression (δ) of melting/solidifying latent heat can be written as Equation (3),δ is defined as the heat energy storage capability. The δ values represent a trend approximately equal to 1 for MG-0 (90.9%), MG-2 (95.4%), MG-4 (96.2%), and MG-6 (98.9%), which indicates further proof from another side that graphene has the capability of enhancing the thermal storage efficiency of microPCMs. Because the microPCMs nearly have similar rE values as shown in Based on the above DSC curves, the melting energy (Δ(1)The size, shell thickness, morphology, and chemical structure of microPCMs were investigated. MMF had a crosslinkage reaction forming a hybrid structure with graphene. It was found that the microPCMs were spherical particles and the graphene enhanced the smoothness degree of the shell surface.(2)The SEM, TEM, AFM, and XPS results ensured the existence of graphene in the shells. It was found that graphene hybrid shells were constructed though forces of electric charge absorption and long-molecular entanglement.(3)TGA results indicated that the graphene additive greatly enhanced the thermal stability of microPCMs. The heating-cooling tests also proved that the microPCMs with more graphene in the shells resisted violent temperature changes without damage.(4)The thermal conductivity tests indicated that the phase change temperature of microPCMs was regulated by the graphene additive because of the reduction of the thermal transfer hindrance of the hybrid shells. At the same time, IRT results also implied that the microPCMs with more graphene had a higher heat transfer capability.(5)DSC tests proved that the latent thermal energy capability of microPCMs had been improved with a higher heat conduction rate. In addition, infrared thermograph observation implied that the microPCMs had a sensitivity response to heat during a phase change cycling possess because of the excellent thermal conductivity of graphene.The microPCM particles containing paraffin were successfully prepared by a self-assembled synthesis method with graphene/MMF hybrid shells. The microstructure and thermal reliability of various microPCM samples were investigated to understand the effects of graphene on the properties. The following conclusions can be drawn,


Asking unanticipated questions in investigative interviews can elicit differences in the verbal behaviour of truth-tellers and liars: When faced with unanticipated questions, liars give less detailed and consistent responses than truth-tellers. Do such differences in verbal behaviour lead to an improvement in the accuracy of interviewers’ veracity judgements? Two empirical studies evaluated the efficacy of the unanticipated questions technique. Experiment 1 compared two types of unanticipated questions , assessing the veracity judgements of interviewers and verbal content of interviewees’ responses. Experiment 2 assessed veracity judgements of independent observers. Overall, the results provide little support for the technique. For interviewers, unanticipated questions failed to improve veracity judgement accuracy above chance. Reality monitoring analysis revealed qualitatively distinct information in the responses to the two unanticipated question types, though little distinction between the responses of truth-tellers and liars. Accuracy for observers was greater when judging transcripts of unanticipated questions, and this effect was stronger for spatial and temporal questions than planning questions. The benefits of unanticipated questioning appear limited to post-interview situations. Furthermore, the type of unanticipated question affects both the type of information gathered and the ability to detect deceit. Bond et al’s  influentAsking questions that an interviewee has not anticipated should, according to Vrij , increasThe majority of studies investigating the efficacy of the approach have focussed on post-hoc analyses of interviewees’ verbal behaviour , as opposed to real-time veracity judgements made by interviewers. Research to date has not addressed whether effects of asking unanticipated questions are noticeable to the interviewer. The present study was designed to evaluate the unanticipated questions technique, specifically whether its efficacy extends to real-time veracity judgements.The unanticipated questions approach, it is suggested, exploits differences in the cognitive load faced by truth-tellers and liars. It is well established that telling a lie imposes greater cognitive load on the individual than telling the truth ,18. ResuGiven the opportunity, liars plan how they will behave and what they will say when interviewed . As partClemens et al  argue thOther studies have focussed on spatial and temporal details as the basis for unanticipated questions ,30. VrijAlthough the unanticipated questions approach has received considerable support in terms of its ability to distinguish true and false accounts on the basis of verbal cues ,13, therThe majority of unanticipated question studies comprise post-hoc analyses of interviewees’ verbal behaviour, looking at differences in the level of detail, consistency and statement length ,9,14,34.Unanticipated questions may elicit verbal cues to deceit, but their effects on judgements of the interviewer are unknown. Vrij et al’s  meta-anaThe studies presented below examined the effects of unanticipated questions using three different empirical approaches. Experiment 1 provided a within-experiment comparison of the effectiveness of unanticipated planning and unanticipated spatial/temporal questions, to determine if the use of unanticipated questions leads to improved accuracy in the real-time veracity judgements made by interviewers. The resulting interviews were analysed using the Reality Monitoring (RM) framework  to examiIn this experiment, truth-tellers completed a task which involved navigating around a university campus, while liars had to pretend to have conducted the same task. All interviewees were subsequently told to convince an interviewer that they had carried out the task. The interview questions were either questions that might be anticipated by interviewees , unanticipated questions about the planning of the task , or unanticipated questions regarding spatial and temporal details . Immediately following the interviews, interviewers made a veracity judgement concerning the interviewee’s account and were asked what information they based their decision on.Based on previous work by Vrij and colleagues showing unanticipated questions in interviews results in differences in the verbal behaviour of truth-tellers and liars ,14, inteThe experiment also investigated differences in the verbal responses provided by truth tellers and liars, and whether they are amplified by asking unanticipated questions. The Reality Monitoring (RM) framework  asserts Unanticipated questions are designed to force the interviewee into providing a spontaneous, unprepared answer and as such a dishonest interviewee should have less opportunity to access related experience from memory . ResearcThe number of words falling into the four RM categories was measured for each interview transcript using the linguistic analysis software LIWC . Based oage = 21.52, SD = 4.32) and 18 were male . A further 60 interviewees were assigned to the liar condition. Of these, 47 were female  and 13 were male . Interviewees were UG and PG students recruited from a range of science and arts disciplines at the University of Sussex. Interviewees received either course credits or £5 for taking part. As an additional incentive, they were told that they would receive a further £5 if they were successful in convincing the interviewer that they were telling the truth. In reality, all interviewees received this extra money regardless of performance. This study was approved by the Sciences & Technology Cross-Schools Research Ethics Committee at the University of Sussex. All participants provided written consent.Sixty interviewees were assigned to the truth-teller condition. Of these, 42 were female  and four male  Psychology doctoral students at the University of Sussex were selected to carry out the interviews. All attended training which comprised classroom-based instruction and practical exercises on using the interview protocol devised for this research, which consisted of a fixed set of questions varying by condition  or liar (n = 60) conditions. Interviewees were further randomly assigned to one of three interview conditions: anticipated (n = 40), planning (n = 40), or spatial/temporal (n = 40). Assignment was balanced across condition so that for each of the interview conditions, half were truth-tellers and half were liars.A between-groups design was employed, with interviewees randomly assigned to either truth-teller  and then left the room, leaving the interviewer to ask the set of questions. Each of the question lists consisted of ten questions. The first five questions were the same in each list and consisted of general questions about the task that interviewees might have anticipated, such as “What task did you carry out around the campus today?” and “Describe the route you took from Room A to Room B.” The remaining questions differed according to condition: In the general condition, they were further general questions similar to the first five, such as “How many boxes were there in Room B?” In the planning condition, questions  focusseIn order to prevent the interviewers from gaining advantageous information as the experiment progressed, , they were never given feedback on their performance until all twelve interviews had been completed.When the interview was complete, the interviewee completed two questionnaires. The first listed the ten questions that they had been asked and required them to state, using a 7-point Likert scale, how much they had anticipated each question prior to interview. The second gathered information, again using 7-point Likert scales, regarding how deceptive/truthful they had been, how cognitively demanding they found the interview, and how motivated they were to comply with the instructions.The interviewers also completed a questionnaire after each interview in which they indicated whether they felt the interviewee had been lying or telling the truth, firstly on a 7-point Likert scale and secondly using a dichotomous forced choice decision. The questionnaire also required them to explain any verbal or non-verbal information they had based their decision on. Responses were subsequently coded as one of four categories: Verbal Content, such as “specific details in responses” or “consistency in responses”; Verbal Delivery, such as “tone of voice” or “responses seeming rehearsed”; Non-verbal Passive, such as “nervous demeanour” or “level of confidence”; and Non-verbal Active, such as “hand movements”, “body language” or “eye contact”.t (118) = -35.54, p < .001, d = 6.49, 95% CI . Motivation to comply was high in both groups, with no difference in ratings between truth tellers  and liars , t (118) = -0.10, p = .93.Interviewees were asked to rate the extent to which they had been deceptive in the interview on a seven-point Likert scale . Interviewees assigned to liar conditions reported being more deceptive  than those in the truth-teller condition , F  = 2.13, p = .15, nor a main effect of question type, F  = 0.41, p = .66. There was also not a significant veracity × question type interaction, F  = 0.38, p = .69.Transcripts of the interviews were assessed to establish whether the interviewers had adhered to the interview protocol. The total number of deviations from the 10-question script was calculated for each interview. Deviations included missing out a question, changing the order of the questions, altering the wording of a question, asking an incomplete question, or asking an additional question. Overall, the number of deviations in each interview was low  and the majority were due to interviewers slightly rephrasing questions to help the interviewee understand. A 2 (veracity: truth-teller or liar) × 3  between-groups ANOVA showed no main effect of veracity, F  = 0.95, p = .33, nor a significant veracity × question type interaction, F  = 1.45, p = .24. There was a significant main effect of question type, F  = 20.83, p < .001, F = 41.30, p < .001, d = 1.24, 95% CI . However, there was no significant difference in anticipation of planning questions  and spatial/temporal questions , F = 0.36, p = .55.Interviewees rated the extent to which they had anticipated each question on a seven-point scale . Mean anticipation was calculated for the final five questions of each interview. A 2 (veracity: truth-teller or liar) × 3  between-groups ANOVA showed no main effect of veracity, t-test showed that this was not significantly different from chance (50% correct), t (119) = 0.91, p = .36. In a series of one-sample t-tests (see t (19) = 2.52, p = .021, d = 0.56, 95% CI . However, performance was significantly worse than chance at identifying liars, t (19) = -3.27, p = .004, d = 0.73, 95% CI . For truth-tellers and liars combined, performace was not significantly different from chance, t (39) = -0.31, p = .76.With unanticipated planning questions, performance did not differ from chance at interviewing truth-tellers, t (19) = 0.89, p = .39, liars, t (19) = -0.89, p = .39, or for truth-tellers and liars combined, t (39) = 0, p = 1. With unanticipated spatial/temporal questions, interviewers were significant better than chance at identifying truth-tellers, t (19) = 2.52, p = .021, d = 0.56, 95% CI , but not at identifying liars, t (19) = 0.44, p = .67. For truth-tellers and liars combined, interviewer accuracy with the unanticipated spatial/temporal questions was also not significantly greater than chance, t (39) = 1.96, p = .06.The interviewer made a dichotomous decision post-interview regarding the veracity of each interviewee, and did so for two interviewees in each of the six conditions. The overall mean accuracy was 54%. A one-sample ests see  accuracyF  = 13.05, p = .006, F  = 1.56, p = .27, nor the interaction between Veracity and Question Type, F  = 2.45, p = .15, was significant.To investigate the relative effects of veracity and question type on the interviewers’ dichotomous judgement accuracy , a 2 (veracity: truth-teller or liar) × 3  repeated measures ANOVA was conducted. There was a significant effect of Veracity, Interviewers were also asked to rate the extent to which they thought the interviewee was telling the truth or lying on a seven-point scale . Scores in the liar conditions were reversed so that higher scores indicate greater accuracy. F  = 16.10, p = < .001, F  = 4.70, p = .011, F  = 1.88, p = .157. Planned contrasts reveal that accuracy was greater for truth-tellers  than for liars , F = 16.10, p < .001, d = 0.71, 95% CI . The difference in accuracy between truth-tellers and liars was significantly greater for the anticipated questions  than the two unanticipated question types combined , F = 9.36, p = .003, d = 0.61. However, there was no difference between the unanticipated spatial/temporal and unanticipated planning questions, F = 0.01, p = .95.To investigate the effects of veracity and question type, a 2 (veracity: truth-teller or liar) × 3  between-groups ANOVA was performed on level of accuracy. There was a significant main effect of veracity, F  = 95.32, p < .001, F  = 13.75, p < .001, F  = 0.02, p = .98. Planned comparisons revealed that, overall, liars found the interviews more difficult  than the truth-tellers , F = 95.32, p < .001, d = 1.63, 95% CI . Interviewees found the unanticipated questions combined  more cognitively demanding than the anticipated questions , F = 16.98, p < .001, d = 0.58, 95% CI . Additionally, spatial/temporal questions  were rated as significantly more cognitively demanding than planning questions , F = 10.53, p = .002, d = 0.53, 95% CI .Interviewees were asked to rate how cognitively demanding they found the interview on a seven-point scale . F  = 6.22, p = .01, F  = 2.89, p = .03, R2 = .04, F  = 1.74, p = .16. Inspection of the data for Step 2 reveals that verbal delivery, and both non-verbal categories were negatively related to interviewer accuracy, indicating that the more of these types of reasons that interviewers based their decisions on, the worse their accuracy became. However, none of these were significant predictors.The reasons that the interviewers reported for their veracity decisions were grouped into four categories: verbal content, verbal delivery, non-verbal passive, and non-verbal active. The total number within each category was calculated for each interview. A multiple regression was performed using these frequencies as predictors with accuracy  as the dependent variable. Verbal content was entered alone in the first step of the model, given that the unanticipated questions approach relies on detecting differences in the verbal content of interviewees’ responses , and ver2(1) = 4.07, p = .05. The greater the number of verbal content reasons that interviewers claimed to base their decisions on, the greater their accuracy levels. Despite this, the model was only able to explain 5% of the variance in accuracy (Nagelkerke R2). The model was no longer significant at step two. The addition of the three remaining predictors did not significantly improve the model, χ2(3) = 3.92, p = .27.The analysis was repeated, with a binary logistic regression, using forced choice accuracy as the dependent variable. The findings were essentially the same as those of the Likert scale data. The model at Step 1 was significantly able to predict interviewer accuracy, χThe text analysis software programme Linguistic Inquiry and Word Count  was useFor each transcript, LIWC determines the amount of words falling into 73 linguistic categories, each presented as percentages of total word count. Four of relevance to RM were analysed: ‘perceptual processes’, ‘relativity’, ‘affective processes’, and ‘cognitive mechanisms’. The ‘perceptual processes’ (or ‘sensory’) category includes words relating to sensory information, such as ‘saw’, ‘heard’, and ‘felt’. The ‘relativity’  category includes spatial and temporal related words, such as ‘down’, ‘arrive’, and ‘during’. The ‘affective processes’ category includes emotion-based words, both positive and negative, such as ‘happy’, ‘hurt’, and ‘worried’. Finally, the ‘cognitive mechanisms’ category includes words associated with thought processes, such as ‘know’, ‘think’, ‘maybe’ and ‘because’. These categories are similar to those used by Bond et al .F  = 0.45, p = .50, nor was there a significant interaction, F  = 0.81, p = .45. However, there was a significant main effect of question type, F  = 7.52, p = .001, t (78) = -3.45, p = .001, d = 0.77, 95% CI  and unanticipated spatial/temporal questions , t (78) = -3.48, p = .001, d = 0.78, 95% CI . There was no significant difference in word count between responses to anticipated questions and unanticipated spatial/temporal questions, t (78) = -0.23, p = .82.In order to explore the effects of veracity and question type on the total number of words spoken by interviewees, a 2 (Veracity: truth-teller or liar) × 3  ANOVA was conducted with word count as the dependent variable . There wF  = 2.59, p = .04, F  = 16.10, p < .001, F  = 2.01, p = .046, F  = 7.59, p = 0.01, t (118) = -2.65, p = .01, d = 0.48, 95% CI . The effects of veracity with the remaining RM criteria were not significant .Univariate tests of the four RM criteria revealed a significant effect of veracity with affective words, F  = 15.00, p < .001, t (78) = 2.96, p = .004, d = 0.66, 95% CI , and unanticipated planning questions , t (78) = 5.10, p < .001, d = 1.14, 95% CI . There was also an effect of question type on affective words, F  = 4.33, p = .02, t (78) = 2.72, p = .01, d = 0.61, 95% CI . Finally, there was a significant effect of question type on cognitive mechanism words, F  = 90.67, p < .001, t (78) = 11.65, p < .001, d = 2.61, 95% CI , and to unanticipated spatial/temporal questions , t (78) = 10.64, p < .001, d = 2.38, 95% CI . There was no significant effect of question type on perceptual details, F  = 0.60, p = .55.There was a significant univariate effect of question type on contextual words, The results of Experiment 1 indicate that the manipulations were successful. The planning and spatial/temporal questions were rated as significantly less anticipated than the anticipated questions. Additionally, participants appeared to comply with the instructions and were motivated to do so. As with all subjective response measures, responses to the post-interview questionnaire may have been influenced by study demand characteristic. Nonetheless, the absence of differences between conditions gives us some degree of confidence that the motivation to conform was high and equivalent across conditions. Overall, the findings of Experiment 1 indicate that unanticipated questions did not increase interviewers’ ability to detect interviewee veracity. The veracity scale judgements and forced choice results show the same pattern: while accuracy for detecting liars increased slightly with unanticipated questions, accuracy at detecting truth-tellers was reduced, particularly with planning questions. As such, the findings fail to support Hypothesis 1. Furthermore, the results do not support the idea that unanticipated questions raise cognitive load for liars but not for truth tellers, failing to support Hypothesis 2. The unanticipated questions approach is grounded in the idea that being asked unanticipated questions in an interview will raise the cognitive load for liars but not truth tellers . HoweverPrevious research has shown that truth tellers use more words associated with sensory, contextual and affective processes than liars, while liars tend to use more cognitive mechanism words than truth tellers –42. The For tasks such as security screeing and police stop-and-search interviews, methods are needed that can be used to determine interviewee veracity in real time. However, in other contexts, the ability to detect deception in a post-hoc fashion is also important. For example, UK police officers are trained according to the PEACE model of investigative interviewing, which states that the purpose of such interviews is to gather information for use by others rather than to determine guilt or innocence directly . The infExperiment 1 found that interviewees used qualitatively different language in response to the three question types, with planning questions yeilding more references to cognitive operations and spatial/temporal questions yeilding more contextual words. Experiment 1 failed to support the unanticipated question approach in terms of its ability to allow interviewers to accurately determine the interviewees’ veracity. However, there was a positive relationship between interviewers’ reported reliance on verbal content when making veracity judgements and their accuracy. Despite this, the literature on detecting deception suggests that individuals rarely base decisions purely on verbal cues, and instead tend to focus on non-verbal behaviour such as eye contact, body movements, and general demeanour ,3. The iBased on these findings ,31, as wage = 30.30, SD = 16.40) and 21 males  took part in the study. Participants voluntarily took part in the experiment as part of an Open Day at the University of Sussex. All gave their informed consent to take part and were free to withdraw at any point. This study was approved by the Sciences & Technology Cross-Schools Research Ethics Committee at the University of Sussex.Ninety females , each answered by either a truth-teller or a liar, creating a total of six conditions. Each participant was presented with one randomly selected transcript from each of the six conditions.Transcripts were taken from the interviews which took place during Experiment 1. Experiment 2 used transcripts of the final five questions in each interview. In order to moderate effects of variation in interviewee response length, the number of words used by the interviewee in each interview was analysed and the lowest and highest five in each of the six conditions were excluded, leaving ten transcripts per condition  and were given a maximum of three minutes to read each transcript. The order in which the six conditions appeared on screen was counter-balanced across participants. Following each transcript, they were asked to indicate whether they thought the interviewee was telling the truth or lying. This was done via both a seven point scale and a dichotomous forced choice decision.t (110) = 2.22, p = .03, d = 0.21, 95% CI , but not liars, t (110) = -1.43, p = .16. When looking at truth-tellers and liars combined, the observer accuracy rate was not significantly greater than chance, t (110) = 0.55, p = .58.With unanticipated planning transcripts, performance did not significantly differ from chance when identifying truth-tellers, t (110) = 1.63, p = .11, or liars, t (110) = 1.63, p = .11, however, with truth-tellers and liars combined, the accuracy did exceed chance level, t (110) = 2.49, p = .014, d = 0.24, 95% CI . With unanticipated spatial/temporal transcripts, accuracy levels exceeded chance for both truth-tellers, t (110) = 3.71, p < .001, d = 0.35, 95% CI , and liars, t (110) = 4.65, p < .001, d = 0.44, 95% CI . When looking at the accuracy rate of truth-tellers and liars combined, observer accuracy was again greater than chance level, t (110) = 5.78, p < .001, d = 0.55, 95% CI .Observers made a dichotomous forced choice decision regarding the veracity of the interviewees in each of the transcripts. A series of one-sample t-tests were carried out to investigate effects of veracity and question type on observer accuracy see . LookingAs well as making a dichotomous forced choice decision, observers were required to rate whether they thought the interviewee was telling the truth or lying on a seven point scale . Scores given to transcripts in the lying condition were reversed meaning that higher scores indicate greater accuracy across all trials. F  = 0.64, p = .43, nor was there a significant interaction, F  = 2.88, p = .06. However, there was a significant main effect of question type, F  = 6.32, p = .002, F  = 6.53, p = .01, F  = 6.13, p = .02, A two way 2 (veracity: truth-teller or liar) × 3  repeated measures ANOVA was performed on rating accuracy. There was no significant main effect of veracity, The findings of Experiment 2 provide only partial support for the unanticipated questions approach , and sugTwo experiments explored the effects of different types of unanticipated question on interviewer and observer veracity judgements, and on the content of interviewee accounts. Experiment 1 compared anticipated, unanticipated planning and unanticipated spatial/temporal questions in investigative interviews, with a focus on interviewers’ veracity judgement accuracy. The findings fail to provide support for the unanticipated questions approach. With dichotomous forced-choice judgements, accuracy for truth-tellers was no greater when interviewers were asking unanticipated planning or spatial/temporal questions than when asking the anticipated questions. For liars, interviewers were more accurate when asking unanticipated compared to anticipated questions, though neither question type yielded accuracy rates significantly greater than chance. With veracity scale judgements, there was no effect of question type. Accuracy was greater for truth-tellers than liars overall, but this difference was diminished when interviewers asked unanticipated questions compared to the anticipated questions. This suggests that the unanticipated questions approach was marginally useful in improving the detection of liars, but impaired the detection of truth-tellers.According to Vrij , unanticExperiment 1 also revealed that verbal content reasons for veracity decisions were positively associated with judgement accuracy. Verbal content can be a reliable indicator of veracity  and the The RM analysis of Experiment 1 found an effect of veracity on affective words, with liars using more than truth-tellers. However, differences in the verbal content of truth tellers’ and liars’ transcripts were not increased by unanticipated questions. These findings do not support claims that unanticipated questions elicit differences in the verbal behaviour of truth-tellers and liars . HoweverOn a positive note, previous advantages of unanticipated questioning for observer judgements were confirmed in Experiment 2, particularly with unanticipated questions that focussed on spatial/temporal details. Moreover, the findings of the dichotomous decisions showed that, in line with the results of Experiment 1, the advantages of asking unanticipated questions was more evident for the detection of liars. The increase in cognitive load experienced by truth-tellers raises the concern that, if used in practical settings, insensitive use of unanticipated questioning may increase the likelihood of mistaking truth-tellers for liars. Spatial/temporal questions emphasise differences in the ways in which truth-tellers and liars use contextual words; planning questions that encourage the discussion of cognitive operations do not.Taken together, the results of the studies provide little support for the unanticipated questions approach to veracity testing. There is some support for the approach in a post-interview observer scenario, though it appears that some forms of unanticipated question will be more successful in this situation than others. Furthermore, the cognitive load explanation provided by Vrij  was refuS1 Appendix(DOCX)Click here for additional data file.S2 Appendix(DOC)Click here for additional data file.S3 Appendix(DOCX)Click here for additional data file.S4 Appendix(DOCX)Click here for additional data file.S5 Appendix(DOCX)Click here for additional data file.S6 Appendix(DOCX)Click here for additional data file.