CT-scan vs.3D surface scanning of a skull:first considerations regarding reproducibility issues

Three-dimensional surface scanning(3DSS)and multi-detector computed tomography(MDCT)are two techniques that are used in legal medicine for digitalizing objects,a body or body parts such as bones.While these techniques are more and more commonly employed,surprisingly little information is known about the quality rendering of digitalized three-dimensional(3D)models provided by each of them.This paper presents findings related to the measurement precision of 3D models obtained through observation of a study case,where a fractured skull reconstructed by an anthropologist was digitalized using both post-mortem imaging methods.Computed tomography(CT)scans were performed using an 8-row MDCT unit with two different slice thicknesses.The variability of 3D CT models superimposition allowed to assess the reproducibility and robustness of this digitalization technique.Furthermore,two 3D surface scans were done using a professional high resolution 3D digitizer.The comparison of 3D CT-scans with 3D surface scans by superimposition demonstrated several regions with significant differences in topology(average difference between+1.45 and-1.22 mm).When comparing the reproducibility between these two digitalizing techniques,it appeared that MDCT 3D models led in general to greater variability for measurement precision between scanned surfaces.Also,the reproducibility was better achieved with the 3D surface digitizer,showing 3D models with fewer and less pronounced differences(from+0.32 to-0.31 mm).These experiments suggest that MDCT provides less reproducible body models than 3D surface scanning.But further studies must be undertaken in order to corroborate this first impression,and possibly explain the reason for these findings.

Bioactive conformation analysis of anthranilic diamide insecticides:DFT-based potential energy surface scanning and 3D-QSAR investigations

Anthranilic diamides are fasting growing class insecticides in modern crop protection for their high activity, low ecotoxicity, and broad insecticidal spectra. However. the bioactive conformations of anthranilic diamides are still unclear until now. In the present study, DFT-based potential energy surface scanning was used to detect the low energy conformations of chlorantraniliprole, then were used respectively in the structure alignment for a series of anthranilic diamide compounds followed by detailed CoMFA and CoMSIA analyses. Finally, the bioactive conformations of anthranilic diamide insecticides were revealed from a series of low energy conformations, which might provide some clues for future insecticide design.

Virtual anthropology:a preliminary test of macroscopic observation versus 3D surface scans and computed tomography(CT)scans

Virtual anthropology(VA)is based on applying anthropological methods currently used to analyse bones to 3D models of human remains.While great advances have been made in this endeavour in the past decade,several interrogations concerning how reliable these models are and what their proper use should be remain unanswered.In this research,a fundamental assumption of VA has been investigated:if the way we perceive and apply an anthropological method is truly similar when looking at bones macroscopically and through various 3D media.In order to answer,10 skulls of known age and sex were scanned using a computed tomography(CT)scanner and a 3D surface scanner.Two observers separately applied a defined staging method to eight suture sites on these skulls,first looking at the bone macroscopically,then at the 3D surface scan,and finally on the CT scan.Two rounds of observation were carried out by each observer.Intra-and inter-observer error were evaluated,and two sample t-tests used to evaluate if the different types of medium used yielded significantly different observations.The results show a high degree of inter-observer error,and that data obtained from 3D surface scans differ from macroscopic observation(confidence level 95%,P≤0.05).CT scans,in these settings,yielded results comparable to those obtained through macroscopic observations.These results offer many possibilities for future research,including indications on the kind of anthropological methods and anatomical landmarks that might be reliably transferable to the virtual environment.All current methods used in traditional anthropology should be tested,and if they prove unreliable,new techniques to analyse bones from virtual models should be developed.

SURFACE PRESSURE,SURFACE POTENTIAL AND SCANNING TUNNELING MICROSCOPY STUDIES FOR N-DOCOSYLPYRIDINIUM-TCNQ MONOLAYER

Simultaneous measurements of surface pressure and surface potential and scanning tunneling microscopy study for N-docosylpyridinium- TCNQ monolayer were carried out.These methods allow us to get more informations on properties of the monolayer.The molecules at the final stage of compression are really in compact stack although a voluminous hydrophilic head exists in the molecule.

Comparison of TMI and AMSR-E sea surface temperatures with Argo near-surface temperatures over the global oceans

Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） were compared with non-pumped near-surface temperatures（NSTs） obtained from Argo profiling floats over the global oceans. Factors that might cause temperature differences were examined, including wind speed, columnar water vapor, liquid cloud water, and geographic location. The results show that both TMI and AMSR-E SSTs are highly correlated with the Argo NSTs; however, at low wind speeds, they are on average warmer than the Argo NSTs. The TMI performs slightly better than the AMSR-E at low wind speeds, whereas the TMI SST retrievals might be poorly calibrated at high wind speeds. The temperature differences indicate a warm bias of the TMI/AMSR-E when columnar water vapor is low, which can indicate that neither TMI nor AMSR-E SSTs are well calibrated at high latitudes. The SST in the Kuroshio Extension region has higher variability than in the Kuroshio region. The variability of the temperature difference between the satellite-retrieved SSTs and the Argo NSTs is lower in the Kuroshio Extension during spring. At low wind speeds, neither TMI nor AMSR-E SSTs are well calibrated, although the TMI performs better than the AMSR-E.

ACQUIREMENT AND COMPUTER PROCESSING OF 3-D SURFACE SHAPE DATA

The laser scanning and CCD image-transmitting measurement method and principle on acquiring 3-D curved surface shape data are discussed. Computer processing technique of 3-D curved surface shape(be called“ 3 - D surface shape”for short) data is analysed. This technique in- cludes these concrete methods and principles such as data smoothing, fitting, reconstructing ,elimi- nating and so on. The example and result about computer processing of 3- D surface shape data are given .

Periodic energy decomposition analysis for electronic transport studies as a tool for atomic scale device manufacturing

Atomic scale manufacturing is a necessity of the future to develop atomic scale devices with high precision.A different perspective of the quantum realm,which includes the tunnelling effect,leakage current at the atomic-scale,Coulomb blockade and Kondo effect,is inevitable for the fabrication and hence,the mass production of these devices.For these atomic-scale device development,molecular level devices must be fabricated.Proper theoretical studies could be an aid towards the experimental realities.Electronic transport studies are the basis to realise and interpret the problems happening at this minute scale.Keeping these in mind,we present a periodic energy decomposition analysis(pEDA)of two potential candidates for moletronics:phthalocyanines and porphyrins,by placing them over gold substrate cleaved at the(111)plane to study the adsorption and interaction at the interface and then,to study their application as a channel between two electrodes,thereby,providing a link between pEDA and electronic transport studies.pEDA provides information regarding the bond strength and the contribution of electrostatic energy,Pauli’s energy,orbital energy and the orbital interactions.Combining this analysis with electronic transport studies can provide novel directions for atomic/close-toatomic-scale manufacturing(ACSM).Literature survey shows that this is the first work which establishes a link between pEDA and electronic transport studies and a detailed pEDA study on the above stated molecules.The results show that among the molecules studied,porphyrins are more adsorbable over gold substrate and conducting across a molecular junction than phthalocyanines,even though both molecules show a similarity in adsorption and conduction when a terminal thiol linker is attached.A further observation establishes the importance of attractive terms,which includes interaction,orbital and electrostatic energies,in correlating the pEDA study with the transport properties.By progressing this research,further developments could be possible in atomic-scale manufacturing in the future.

Road surface condition sensor based on scanning detection of backward power

A method of detecting dry, icy and wet road surface conditions based on scanniag detection of single wavelength backward power is proposed in this letter. The detector is used to receive the backward scattered power which changes with the incidence angle. The relationship between backward power and incidence angle is used to find out the effective angle range and distinguish method. Experiment and simulation show that it is feasible to classifv these three conditions within incidence angle of 5.3 degree.

A review of the growth and structures of silicene on Ag(111)

Ag(111) is currently the most often used substrate for growing silicene films. Silicene forms a variety of different phases on the Ag(111) substrate. However, the structures of these phases are still not fully understood so far. In this brief review we summarize the growth condition and resulting silicene phases on Ag(111), and discuss the most plausible structural model and electronic property of individual phases. The existing debates on silicene on Ag(111) system are clarified as mush as possible.

Stabilization technology and corrosion mechanism of rust layer on Q370 weathering steel surface

A newly developed rust layer on Q370qENH weathering steel(sample C)was studied under dry–wet cycle test of 3.5 wt.%NaCl solution and salt spray test,compared with the bare weathering steel(sample A)and the weathering steel with additive contents(CuSO_(4)0.2,FeSO_(4)0.1,NaHSO_(3)0.02,NaCl 0.02,Na_(2)HPO_(4)0.01,and water balance,in mass%,termed as sample B).Corrosion mechanism of Q370qENH weathering steel after different surface treatments was investigated by means of surface potential scanning,mass change,polarization curve,and X-ray diffraction.The results of X-ray diffraction indicate that rust of bare weathering steel has rare Fe_(3)O_(4),and a dense oxide layer mainly composed of Fe_(3)O_(4) is formed on rust of both sample B and sample C.The surface potential of sample A gradually increases to−0.2 V in the dry–wet cycle test,while the surface potential of sample A maintains at about−0.6 V in the salt spray test.The surface potential of sample B and sample C is higher than that of sample A in the early stage and remains stable during the short-term accelerated corrosion test.Moreover,the mass change of sample C gradually stabilizes with time in the dry–wet cycle and salt spray test.The corrosion current of the sample A is lower than that of sample C in the initial stage of short-term accelerated corrosion test.However,the corrosion current of sample C is smaller than that of the sample A in the experiment.The main components of the deep rust of sample A areγ-FeOOH andα-FeOOH,while those of the deep rust of sample B and sample C are Fe_(3)O_(4).

On-surface construction of low-dimensional nanostructures with terminal alkynes: Linking strategies and controlling methodologies

Bottom-up approach to constructing low-dimensional nanostructures on surfaces with terminal alkynes has drawn great interest because of its potential applications in fabricating advanced functional nanomaterials. The diversity of the achieved products manifests rich chemistry of terminal alkynes and hence careful linking strategies and proper controlling methodologies are required for selective preparations of high-quality target nanoarchitectures. This review summarizes various on-surface linking strategies for terminal alkynes, including non-bonding interactions as well as organometallic and covalent bonds, and presents examples to show effective control of surface assemblies and reactions of terminal alkynes by variations of the precursor structures, substrates and activation modes. Systematic studies of the on-surface linkage of terminal alkynes may help efficient and predictable preparations of surface nanomaterials and further understanding of surface chemistry.

Scanning electron microscopy imaging of single-walled carbon nanotubes on substrates

Scanning electron microscopy （SEM） plays an indispensable role in nanoscience and nanotechnology because of its high efficiency and high spatial resolution in characterizing nanomaterials. Recent progress indicates that the contrast arising from different conductivities or bandgaps can be observed in SEM images if single-walled carbon nanotubes （SWCNTs） are placed on a substrate. In this study, we use SWCNTs on different substrates as model systems to perform SEM imaging of nanomaterials. Substantial SEM observations are conducted at both high and low acceleration voltages, leading to a comprehensive understanding of the effects of the imaging parameters and substrates on the material and surface-charge signals, as well as the SEM imaging. This unified picture of SEM imaging not only furthers our understanding of SEM images of SWCNTs on a variety of substrates but also provides a basis for developing new imaging recipes for other important nanomaterials used in nanoelectronics and nanophotonics.

Distance dependence of atomic-resolution near-field imaging on α-Al2O3 （0001） surface with respect to surface photovoltage of silicon probe tip

Recently, we achieved atomic-resolution optical imaging with near-field scanning optical microscopy using photon-induced force detection. In this technique, the surface photovoltage of the silicon-tip apex induced by the optical near field on the surface is measured as the electrostatic force. We demonstrated atomicresolution imaging of the near field on the α-Al2O3 （0001） surface of a prism. We investigated the spatial distribution of the near field by scanning at different tip-sample distances and found that the atomic corrugation of the near-field signal was observed at greater distances than that of the atomic force microscopy signal. As the tip-sample distance increased, the normalized signal-to-noise ratio of the near field is in a gradual decline almost twice that of the frequency shift （Δf）.

The structure of 4-hydroxylphenylpyruvate dioxygenase complexed with 4-hydroxylphenylpyruvic acid reveals an unexpected inhibition mechanism

4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid(HPPA)to homogentisic acid(HGA).The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests.Recently,we reported the crystal structure of Arabidopsis thaliana HPPD(At HPPD)complexed with HPPA and a cobalt ion,which was supposed to mimic the pre-reactive structure of At HPPD-HPPA-Fe(II).Unexpectedly,the present study shows that the restored At HPPD-HPPA-Fe(II)complex is still nonreactive toward the bound dioxygen.QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring,and the residue Phe381 plays a key role in orienting the phenyl ring.Kinetic study on the F381 A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex.More importantly,the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors,suggesting that these inhibitors resist the association of dioxygen(and exert their inhibitory roles)in the same way as the HPPA.The present study provides insights into the inhibition mechanism of HPPD inhibitors.

Digital reconstruction of fragmented tooth remains in forensic context

Forensic odontology majorly focuses on the identification of victims through the analyses of oral and para-oral structures.Exposure to high temperatures and trauma can occur in mass disasters and may lead to the fracturing and fragmentation of teeth.These fragments may become very fragile and easily damaged while handling.Conventional methodologies such as the use of transparent nail polish,hair spray,cyanoacrylate or adhesives have been used to stabilise the fragmented pieces.This study introduces a new and innovative digital technique that utilises three-dimensional surface scanning(3DSS)and rapid prototyping techniques to reconstruct fractured portions of the teeth.The results of qualitative congruency analysis suggest that over all variance of morphological error(0.0526±0.05)mm.These results imply that the reconstructed 3D model can be used for various morphometric analyses.

The study of the interactions between graphene and Ge（001）/Si（001）

The interaction between graphene and germanium surfaces was investigated using a combination of microscopic and macroscopic experimental techniques and complementary theoretical calculations.Density functional theory （DFT） calculations for different reconstructions of the Ge（001） surface showed that the interactions between graphene and the Ge（001） surface introduce additional peaks in the density of states,superimposed on the graphene valence and conduction energy bands.The growth of graphene induces nanofaceting of the Ge（001） surface,which exhibits well-organized hill and valley structures.The graphene regions covered by hills are of high quality and exhibit an almost linear dispersion relation,which indicates weak graphene-germanium interactions.On the other hand,the graphene component occupying valley regions is significantly perturbed by the interaction with germanium.It was also found that the stronger graphene-germanium interaction observed in the valley regions is connected with a lower local electrical conductivity.Annealing of graphene/Ge（001）/Si（001） was performed to obtain a more uniform surface.This process results in a surface characterized by negligible hill and valley structures;however,the graphene properties unexpectedly deteriorated with increasing uniformity of the Ge（001） surface.To sum up,it was shown that the mechanism responsible for the formation of local conductivity inhomogeneities in graphene covering the Ge（001） surface is related to the different strength of graphene-germanium interactions.The present results indicate that,in order to obtain high-quality graphene,the experimental efforts should focus on limiting the interactions between germanium and graphene,which can be achieved by adjusting the growth conditions.

Direct discrimination between semiconducting and metallic single-walled carbon nanotubes with high spatial resolution by SEM

Single-walled carbon nanotube （SWCNT） films with a high density exhibit broad functionality and great potential in nanodevices, as SWCNTs can be either metallic or semiconducting in behavior. The films greatly benefit from characterization technologies that can efficiently identify and group SWCNTs based on metallic or semiconducting natures with high spatial resolution. Here, we developed a facile imaging technique using scanning electron microscopy （SEM） to discriminate between semiconducting and metallic SWCNTs based on black and white colors. The average width of the single-SWCNT image was reduced to -9 nm, -1/5 of previous imaging results. These achievements were attributed to reduced surface charging on the SiOdSi substrate under enhanced accelerating voltages. With this identification technique, a CNT transistor with an on/off ratio of 〉10s was fabricated by identifying and etching out the white metallic SWCNTs. This improved SEM imaging technique can be widely applied in evaluating the selective growth and sorting of SWCNTs.

Dipole and charge effects of chloroaluminum phthalocyanine revealed by local work function measurements at sub-molecular level

Work function plays a significant role in surface chemistry. Local work function provides the information of local d/pole-d/pole interaction and charge distribution between adsorbates and substrate, highlighting the local charge effect of the targeted spot which is normally smeared out in conventional average work function measurements. Chloroaluminum phthalocyanine （CIA1Pc）, an important optoelectronic molecule with a permanent dipole moment pointing from the Pc ring to the ending CI atom, adsorbed on Au（111） in either Cl-up or Cl-down configuration. Scanning tunneling microscopy/spectroscopy measurements revealed that at the centers of Cl-up and CI-down molecules, the local work functions changed oppositely with respect to the Au（111） substrate. At their Pc lobes, however, the local work functions unanimously increased due to charging effect of the indole lobes in the CIAIPc molecule.