Diagnostic Efficacy of Metagenomic Next-Generation Sequencing in Patients with Spinal Infections: A Retrospective Study.

Purpose: Early diagnosis of spinal infections remains challenging, and emerging metagenomic next-generation sequencing (mNGS) technology holds promise in addressing this issue. The aim of this study is to investigate the diagnostic efficacy of mNGS in spinal infections. Patients and Methods: A total of 78 cases with suspected spinal infections were enrolled in this study, all of whom underwent laboratory, histopathological and mNGS examinations upon admission. Lesion samples were obtained by surgical or C-arm-guided puncture. Sensitivity, specificity, positive predictive value and negative predictive value of culture and mNGS were calculated for statistical analysis. Results: With histopathological results as the reference, the included 78 patients were categorized into 50 cases in the spinal infection group and 28 cases in the aseptic group. The sensitivity (84%) and negative predictive value (77.14%) of mNGS were significantly higher than those of culture (32% and 44.26%, respectively), whereas no significant differences were observed in terms of specificity and positive predictive value. In the subgroup analysis for Mycobacterium tuberculosis, the sensitivity of mNGS (90.91%) and T-spot (90.91%) was significantly higher than that of culture (0). Additionally, mNGS demonstrated markedly higher specificity (100%) compared to T-spot (85.07%). Conclusion: This study underscores the substantial advantages of mNGS in terms of diagnostic accuracy and bacterial coverage for spinal infections. The findings provide compelling clinical evidence that supports the enhanced diagnostic efficacy of mNGS.

Lumbar Spine Infection with Eikenella corrodens Presented as Abdominal Pain: A Case Report and Literature Review.

Background: Eikenella corrodens is a part of the inherent flora on the surface of human mucosa. It usually does not cause disease unless the patient has been bitten, injured or surgically infected. Lumbar spine infection caused by Eikenella corrodens usually presents with conventional symptoms such as low back pain and fever. Herein, we report a case of lumbar intervertebral space infection with Eikenella corrodens presented as abdominal pain. Case Presentation: A 38-year-old man with no medical history of note presented with abdominal pain. Initially, local doctors suspected that the patient had abdominal disease. However, abdominal diseases were ruled out and only lumbar spine infection was confirmed. Then, the patient was misdiagnosed as lumbar tuberculosis. Finally, anaerobic culture and metagenomic next-generation sequencing confirmed the Eikenella corrodens, which was rarely involved in lumbar intervertebral space infection. The patient recovered after operation and antibiotic therapy. Conclusion: This case indicated a rare symptom of lumbar spine infection, abdominal cramping, which is caused by Eikenella corrodens. Blood culture had low sensitivity as a diagnostic method for Eikenella corrodens, but lesion sample culture or metagenomic next-generation sequencing had high sensitivity for early diagnosis.

Prognostic nomogram in patients with epithelioid sarcoma: A SEER-based study.

OBJECTIVE: The prognostic factors for patients with epithelial sarcoma remain unclear. The study aims to develop a practical clinical nomogram that predicts prognosis in patients with ES using the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: We extracted clinical data from 2004 to 2015 from the SEER database about patients with ES. All patients were randomly divided into training cohort and validation cohort. Kaplan-Meier analyses were used to compare outcomes between different subgroups. In order to estimate the chance of survival for patients with ES, we developed a nomogram. Nomogram performance was evaluated by discrimination and calibration. Additionally, an analysis of decision curves was conducted to evaluate the clinical usefulness of this newly developed model. RESULTS: In the primary cohort,320 met the inclusion criteria to be entered into this study. The median OS was 66.000 months (range 34.704 to 94.296 months), and the 1-, 3-, and 5-year OS rates were 70.7%, 56.1%, and 50.4%, respectively. For the validation cohort, we studied 136 consecutive patients. Age, primary site, grade, AJCC (American Joint Committee on Cancer) T, AJCC M, and surgery were included in the nomogram. The C-index values for the training set and validation set were 0.817 and 0.832, respectively. The calibration plots showed good agreement between the prediction and the observation. Based on the clinical decision curve, the model has a good clinical net benefit for ES patients. CONCLUSIONS: It is the first study that developed an effective survival prediction model for patients with ES. Using this nomogram can assist in clinical decision-making as it has satisfactory accuracy. Even so, additional external validation is needed.

Measurement method of aero-engine rotor concentricity and perpendicularity based on deep belief neural network.

When implementing the traditional assembly method, the rotor is affected by machining errors. The morphology of the rotor is complex, and the machining error of the rotors at all levels are transmitted step by step through the stop mating surface, which affects the performance and service life of the aero-engine. The evaluation of machining error of single-stage rotor is the basis of assembly quality of multi-stage rotor. In order to improve the current situation of complicated and time-consuming rotor machining error evaluation, this paper proposes to establish a deep belief neural network (DBNN) to replace the traditional procedure of depolarization. The network takes the relative evaluation error of the rotor profile data without depolarization as the input and takes the machining error of the rotors obtained after depolarization as the output. First, the evaluation mechanism of the rotor's machining error is analyzed, and the corresponding machining error influence source is selected as the input source of the deep belief neural network. Second, as DBNN is trained, and the appropriate weight initialization method and the optimization algorithm of the prediction network are selected to ensure the optimization of the whole network for feature mapping extraction of the training set. Finally, the assembly of multi-stage rotors is simulated and analyzed. It is shown in the experiments that after the iteration, the prediction network, with good training effects, has converged, and its prediction results tend to be consistent with the real values. The mean prediction error of the concentricity is 0.09 µm while the mean difference of angle of concentricity error value is 0.77°, and the mean difference of perpendicularity error value is 0.21 µm while the mean difference of angle of perpendicularity error value is 1.4°, the corresponding R2 determination coefficients were 0.99, 0.98, 0.91, and 0.94, respectively. It meets the requirements of field assembly and fully embodies the effectiveness of the procedure of depolarization based on deep confidence neural network.

Lattice Strain and Surface Activity of Ternary Nanoalloys under the Propane Oxidation Condition.

The ability to harness the catalytic oxidation of hydrocarbons is critical for both clean energy production and air pollutant elimination, which requires a detailed understanding of the dynamic role of the nanophase structure and surface reactivity under the reaction conditions. We report here findings of an in situ/operando study of such details of a ternary nanoalloy under the propane oxidation condition using high-energy synchrotron X-ray diffraction coupled to atomic pair distribution function (HE-XRD/PDF) analysis and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The catalysts are derived by alloying Pt with different combinations of second (Pd) and third (Ni) transition metals, showing a strong dependence of the catalytic activity on the Ni content. The evolution of the phase structure of the nanoalloy is characterized by HE-XRD/PDF probing of the lattice strain, whereas the surface activity is monitored by DRIFTS detection of the surface intermediate formation during the oxidation of propane by oxygen. The results reveal the dominance of the surface intermediate species featuring a lower degree of oxygenation upon the first C-C bond cleavage on the lower-Ni-content nanoalloy and a higher degree of oxygenation upon the second C-C bond cleavage on the higher-Ni-content nanoalloy. The face-centered-cubic-type phase structures of the nanoalloys under the oxidation condition are shown to exhibit Ni-content-dependent changes of lattice strains, featuring the strongest strain with little variation for the higher-Ni-content nanoalloy, in contrast to the weaker strains with oscillatory variation for the lower-Ni-content nanoalloys. This process is also accompanied by oxygenation of the metal components in the nanoalloy, showing a higher degree of oxygenation for the higher-Ni-content nanoalloy. These subtle differences in phase structure and surface activity changes correlate with the Ni-composition-dependent catalytic activity of the nanoalloys, which sheds a fresh light on the correlation between the dynamic change of atomic strains and the surface reactivity and has significant implications for the design of oxidation catalysts with enhanced activities.

Dimensional Design and Core-Shell Engineering of Nanomaterials for Electromagnetic Wave Absorption.

Electromagnetic (EM) wave absorption materials possess exceptionally high EM energy loss efficiency. With vigorous developments in nanotechnology, such materials have exhibited numerous advanced EM functions, including radiation prevention and antiradar stealth. To achieve improved EM performance and multifunctionality, the elaborate control of microstructures has become an attractive research direction. By designing them as core-shell structures with different dimensions, the combined effects, such as interfacial polarization, conduction networks, magnetic coupling, and magnetic-dielectric synergy, can significantly enhance the EM wave absorption performance. Herein, the advances in low-dimensional core-shell EM wave absorption materials are outlined and a selection of the most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship are comprehensively summarized. Moreover, the investigation of the cutting-edge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented.

Assessing Plasmonic Nanoprobes in Electromagnetic Field Enhancement for SERS Detection of Biomarkers.

The exploration of the plasmonic field enhancement of nanoprobes consisting of gold and magnetic core@gold shell nanoparticles has found increasing application for the development of surface-enhanced Raman spectroscopy (SERS)-based biosensors. The understanding of factors controlling the electromagnetic field enhancement, as a result of the plasmonic field enhancement of the nanoprobes in SERS biosensing applications, is critical for the design and preparation of the optimal nanoprobes. This report describes findings from theoretical calculations of the electromagnetic field intensity of dimer models of gold and magnetic core@gold shell nanoparticles in immunoassay SERS detection of biomarkers. The electromagnetic field intensities for a series of dimeric nanoprobes with antibody-antigen-antibody binding defined interparticle distances were examined in terms of nanoparticle sizes, core-shell sizes, and interparticle spacing. The results reveal that the electromagnetic field enhancement not only depended on the nanoparticle size and the relative core size and shell thicknesses of the magnetic core@shell nanoparticles but also strongly on the interparticle spacing. Some of the dependencies are also compared with experimental data from SERS detection of selected cancer biomarkers, showing good agreement. The findings have implications for the design and optimization of functional nanoprobes for SERS-based biosensors.

Molecularly-tunable nanoelectrode arrays created by harnessing intermolecular interactions.

Intermolecular interactions play a critical role in the binding strength of molecular assemblies on surfaces. The ability to harness them enables molecularly-tunable interfacial structures and properties. Herein we report the tuning of the intermolecular interactions in monolayer assemblies derived from organothiols of different structures for the creation of nanoelectrode arrays or ensembles with effective mass transport by a molecular-level perforation strategy. The homo- and hetero-intermolecular interactions can be fully controlled, which is demonstrated not only by thermodynamic analysis of the fractional coverage but also by surface infrared reflection absorption and X-ray photoelectron spectroscopic characterizations. This understanding enables controllable electrochemical perforation for the creation of ensembles or arrays of channels across the monolayer thickness with molecular and nanoscale dimensions. Redox reactions on the nanoelectrode array display molecular tunability with a radial diffusion characteristic in good agreement with theoretical simulation results. These findings have implications for designing membrane-type ion-gating, electrochemical sensing, and electrochemical energy storage devices with molecular level tunability.

Strain sensors fabricated by surface assembly of nanoparticles.

Harnessing interparticle spatial properties of surface assembly of nanoparticles (SAN) on flexible substrates is a rapidly emerging front of research in the design and fabrication of highly-sensitive strain sensors. It has recently shown promising potentials for applications in wearable sensors and skin electronics. SANs feature 3D structural tunability of the interparticle spatial properties at both molecular and nanoscale levels, which is transformative for the design of intriguing strain sensors. This review will present a comprehensive overview of the recent research development in exploring SAN-structured strain sensors for wearable applications. It starts from the basic principle governing the strain sensing characteristics of SANs on flexible substrates in terms of thermally-activated interparticle electron tunneling and conductive percolation. This discussion is followed by descriptions of the fabrication of the sensors and the proof-of-concept demonstrations of the strain sensing characteristics. The nanoparticles in the SANs are controllable in terms of size, shape, and composition, whereas the interparticle molecules enable the tunability of the electrical properties in terms of interparticle spatial properties. The design of SAN-derived strain sensors is further highlighted by describing several recent examples in the explorations of their applications in wearable biosensor and bioelectronics. Fundamental understanding of the role of interparticle spatial properties within SANs at both molecular and device levels is the focal point. The future direction of the SAN-derived wearable sensors will also be discussed, shining lights on a potential paradigm shift in materials design in exploring the emerging opportunities in wearable sensors and skin electronics.

Novel Double Endobutton Technique Combined with Three-Dimensional Printing: A Biomechanical Study of Reconstruction in Acromioclavicular Joint Dislocation.

OBJECTIVE: To reconstruct the acromioclavicular (AC) joint using an adjusted closed-loop double Endobutton technique via a guiding locator that was applied using three-dimensional (3D) printing technology. At the same time, the reliability and safety of the novel double Endobutton (NDE) were tested by comparing the biomechanics of this technique with the TightRope (TR) approach. METHODS: This retrospective study was conducted between January 2017 and January 2019. The Department of Anatomy at Southern Medical University obtained 18 fresh-frozen specimens (8 left and 10 right; 12 men and 6 women). First, the guiding locators were applied using 3D printing technology. After preparation of materials, specimens were divided into an NDE group, a TR group, and a normal group. In the NDE and TR groups, the navigation module was used to locate and establish the bone tunnels; after that, the NDE or TR was implanted. However, the Endobuttons were fixed while pressing the distal clavicle downwards and the length of the loop could be adjusted by changing the upper Endobutton in the NDE group while the suture button construct was tensioned and knotted after pressing down the distal clavicle in the TR. Finally, load testing in anterior-posterior (AP), superior-inferior (SI), and medial-lateral (ML) directions as well as load-to-failure testing in the SI direction were undertaken to verify whether the NDE or TR had better biomechanics. RESULTS: In the load testing, the displacements of the NDE and TR groups in the AP, SI, and ML direction were significantly shorter than those of the normal group (P < 0.05). In the load-to-failure testing, the ultimate load of the NDE and TR groups had significantly higher increases than the normal group (722.16 ± 92.04 vs 564.63 ± 63.05, P < 0.05; 680.20 ± 110.29 vs 564.63 ± 63.05, P < 0.05). However, there was no statistically significant difference between the two techniques for these two tests (P > 0.05). In the NDE group, four of six failures were a result of tunnel fractures of the coracoid, while two of six were due to suture breakage. In the TR, three failures were due to coracoid tunnel fractures, one was a result of a clavicle tunnel fracture, and the rest were due to suture breakage. In the normal group, half of the failures were a result of avulsion fractures of the conical ligament at the point of the coracoid process, and the other three were due to rupture of the conical ligament, fracture of the distal clavicle, and fracture of the scapular body. CONCLUSION: As for the TR technique, the stability and strength of the AC joint were better in patients who underwent reconstruction using the NDE technique than in the intact state.

Surface-Mediated Interconnections of Nanoparticles in Cellulosic Fibrous Materials toward 3D Sensors.

Fibrous materials serve as an intriguing class of 3D materials to meet the growing demands for flexible, foldable, biocompatible, biodegradable, disposable, inexpensive, and wearable sensors and the rising desires for higher sensitivity, greater miniaturization, lower cost, and better wearability. The use of such materials for the creation of a fibrous sensor substrate that interfaces with a sensing film in 3D with the transducing electronics is however difficult by conventional photolithographic methods. Here, a highly effective pathway featuring surface-mediated interconnection (SMI) of metal nanoclusters (NCs) and nanoparticles (NPs) in fibrous materials at ambient conditions is demonstrated for fabricating fibrous sensor substrates or platforms. Bimodally distributed gold-copper alloy NCs and NPs are used as a model system to demonstrate the semiconductive-to-metallic conductivity transition, quantized capacitive charging, and anisotropic conductivity characteristics. Upon coupling SMI of NCs/NPs as electrically conductive microelectrodes and surface-mediated assembly (SMA) of the NCs/NPs as chemically sensitive interfaces, the resulting fibrous chemiresistors function as sensitive and selective sensors for gaseous and vaporous analytes. This new SMI-SMA strategy has significant implications for manufacturing high-performance fibrous platforms to meet the growing demands of the advanced multifunctional sensors and biosensors.

The Relationship between Calcaneal Spur Type and Plantar Fasciitis in Chinese Population.

Plantar heel pain is a common disease with a high incidence in different races. It significantly reduced the quality of life of patients. However, the cause of PHP is still controversial and there were varieties of physiological factors associated with PHP. The most common pathological factor in the population was plantar fasciitis. Some existing research studies had found a correlation between calcaneal spurs and plantar fasciitis, and this study had found the correlation in Chinese population. It is invaluable not only to understand the relationship between different types of plantar calcaneal spurs and plantar fasciitis but also to identify the most appropriate treatment strategies. A total of 71 patients with calcaneal spurs were chosen from the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. All 71 patients had completed X-rays and MRI scans; then, surgeons had removed their plantar calcaneal spurs. After surgery, all patients were followed up for 12 months; their prognosis was tested by the VAS and AOFAS scores. Type II (29, 40.8%) had the highest incidence in Chinese population, followed with type I (24, 33.8%) and type III (18, 25.4%). Preoperative VAS scores showed that type II (7.72 ± 1.10) was significantly higher than the other two types (P < 0.001). Postoperative VAS scores of type II were higher than those of type I and type III (P < 0.001). Postoperative AOFAS scores of type II were the lowest (P < 0.001). Researchers had proved that type II was more likely to cause PF.

A simple vaporous probe with atomic-scale sensitivity to structural ordering and orientation of molecular assembly.

Understanding the structural ordering and orientation of interfacial molecular assemblies requires an insight into the penetration depth of the probe molecules which determines the interfacial reactivity. In contrast to the conventional liquid probe-based contact angle measurement in which penetration depth is complicated by the liquid cohesive interaction, we report here a new approach that features a simple combination of vaporous hexane, which involves only van der Waals interaction, and quartz crystal microbalance operated at the third harmonic resonance, which is sensitive to sub-monolayer (0.2%) adsorption. Using this combination, we demonstrated the ability of probing the structural ordering and orientation of the self-assembled monolayers with a sensitivity from penetrating the top portion of the monolayers to interacting with the very top atomic structure at the interface. The determination of the dependence of the adsorption energy of vaporous hexane on the penetration depth in the molecular assembly allowed us to further reveal the atomic-scale origin of the odd-even oscillation, which is also substantiated by density functional theory calculations. The findings have broader implications for designing interfacial reactivities of molecular assemblies with atomic-scale depth precision.

Classification and Morphological Parameters of the Calcaneal Talar Facet: Which Type Is More Likely to Cause Osteoarthritis in Chinese Population?

Due to the calcaneal osteoarthritis, patients had a lower quality of life. This research was to study which type of calcaneus was more likely to cause osteoarthritis and then to guide the clinical prevention and treatment in Chinese population. All 505 intact Chinese calcaneus facets were reconstructed by CT-3D reconstruction scanner and classified into five types based on the calcaneal talar facet (CTF) configuration. CTF's morphology parameters (osteophyte, cortical thickness of calcaneus, GIssane's and Bohler's angle, and long and short axis) were measured and recorded by PACS CT system. Researchers used the length of long and short axis to calculate the CTF area. By comparing the morphology parameters of five types of calcaneus, the differences among different types of calcaneus in Chinese people were statistically different. The study showed that Type II and Type IV had the highest percentage of osteophytes. After being compared and analyzed, the CTF pressure and the subtalar joint stability were closely related to the occurrence of osteoarthritis. Based on the measurement and comparison of morphological parameters in this study, Types II and IV were the most likely to develop osteoarthritis in Chinese population.

Electron Dose-Controlled Formation, Growth, and Assembly of Nanoclusters and Nanoparticles from Aurophilic Au(I)-Thiolate Ensemble on Surfaces.

The ability to precisely control electron irradiation-induced formation, growth, and assembly of nanoclusters or nanoparticles on a solid surface is important for design and creation of catalytically or chemically active surface sites and interfaces free from chemical reducing agents. Here, we show the results of an investigation of the electron dose-controlled formation, growth, and assembly of nanoclusters and nanoparticles in a molecularly assembled thin film of Au(I)-thiolate motifs on a substrate, highlighting an in situ monitoring of the evolution of morphology under controlled electron dose. With aurophilic motifs of Au(I)-thiolate being confined by electrostatic interactions, the sizes of Au nanoclusters and nanoparticles were shown to increase with electron dose, revealing a propensity of a string alignment of the grown nanoclusters and nanoparticles. This growth preference to one-dimensional assembly is supported by the analysis of the surface reaction kinetics in terms of the surface density of electron dose for the growth of the nanoclusters and nanoparticles. The electron dose-controlled size-focusing and directional assembly of nanoclusters and nanoparticles may be exploited as new strategy for the precise control of nanoclusters or nanoparticles and their assemblies on solid surfaces not only free from chemical reducing agent but also with the ability of visual monitoring of the morphological evolution during growth.

Nanoscale Lacing by Electrons.

The ability to harness the optical or electrical properties of nanoscale particles depends on their assembly in terms of size and spatial characteristics which remains challenging due to lack of size focusing. Electrons provide a clean and focusing agent to initiate the assembly of nanoclusters or nanoparticles. Here an intriguing route is demonstrated to lace gold nanoclusters and nanoparticles in string assembly through electron-initiated nucleation and aggregative growth of Au(I)-thiolate motifs on a thin film substrate. This size-focused assembly is demonstrated by controlling the electron dose under transmission electron microscopic imaging conditions. The Au(I)-thiolate motifs, in combination with the molecularly mediated alignment, facilitate the interstring electrostatic and intrastring aurophilic interactions, which functions as a molecular template to aid electron-initiated 1D lacing. The findings demonstrate a hierarchical route for the 1D assemblies with size and spatial tunable catalytic, optical, sensing, and diagnostic properties.

Chemiresistive properties regulated by nanoscale curvature in molecularly-linked nanoparticle composite assembly.

Interparticle spatial properties influence the electrical and functional properties of nanoparticle-structured assemblies. This report describes the nanoscale curvature-induced change in chemiresistive properties of molecularly-linked assemblies of gold nanoparticles on multiwalled carbon nanotubes, which are exploited for sensitive detection of volatile organic compounds. In addition to using linking/capping molecules to define interparticle spatial distances, the nanoscale curvature radius of the carbon nanotubes provides intriguing tunability of the interparticle spatial properties to influence electrical properties, which contrast with those observed for nanoparticle thin films assembled directly on chemiresistor devices. The electrical characteristics of the nanoparticle-nanotube composite give positive response profiles for the vapor molecules that are distinctively different to those observed for conventional nanoparticle thin-film assemblies. The dominant effect of electron coupling on overall chemiresistive properties is shown in relation to that of nanoscale curvature radius on the nanoparticle thin-film sensing properties. Sensing data are also further assessed in correlation with the solubility parameters of the vapor molecule. These findings have significant implications for the design of sensitive interfaces with nanocomposite-structured sensing materials and microfabricated chemiresistor devices.

Assessment of aggregative growth of MnZn ferrite nanoparticles.

MnZn ferrite (MnZnFe2O4, MZF) nanoparticles (NPs) represent an intriguing class of magnetic NPs in terms of composition-tunable magnetic properties, but the ability to control the size and morphology is essential to exploit such properties. This report describes the findings of an investigation of the size and morphology controllability in terms of growth kinetics of the NPs in a thermochemical synthesis process. MZF NPs of different sizes were synthesized at different temperatures. In addition to shape evolution, the overall size of the as-synthesized magnetic NPs is shown to increase with the reaction temperature and reaction time, revealing that the size growth process can be described by an aggregative growth mechanism. While the apparent rate constant decreases with the reaction temperature, the growth factor remains at 1-2, consistent with a low-dimensionality growth mode. Higher temperature and longer reaction time apparently favor the formation of cubic shapes. The dependence of the overall average particle size on the reaction temperature yields a diffusional activation energy in the order of 10-20 kJ mol-1, a value slightly smaller than those reported for aggregative growth of other types of NPs in solutions. The unravelling of the kinetic parameters provides some new insights into the development of strategies for synthesizing MZF NPs with controllable sizes and shapes.

'Squeezed' interparticle properties for plasmonic coupling and SERS characteristics of duplex DNA conjugated/linked gold nanoparticles of homo/hetero-sizes.

The formation of interparticle duplex DNA conjugates with gold nanoparticles constitutes the basis for interparticle plasmonic coupling responsible for surface-enhanced Raman scattering signal amplification, but understanding of its correlation with interparticle spatial properties and particle sizes, especially in aqueous solutions, remains elusive. This report describes findings of an investigation of interparticle plasmonic coupling based on experimental measurements of localized surface plasmon resonance and surface enhanced Raman scattering characteristics for gold nanoparticles in aqueous solutions upon introduction of interparticle duplex DNA conjugates to define the interparticle spatial properties. Theoretical simulations of the interparticle optical properties and electric field enhancement based on a dimer model have also been performed to aid the understanding of the experimental results. The results have revealed a 'squeezed' interparticle spatial characteristic in which the duplex DNA-defined distance is close or shorter than A-form DNA conformation, which are discussed in terms of the interparticle interactions, providing fresh insight into the interparticle double-stranded DNA-defined interparticle spatial properties for the design of highly-sensitive nanoprobes in solutions for biomolecular detection.

Assessing the Role of Capping Molecules in Controlling Aggregative Growth of Gold Nanoparticles in Heated Solution.

This report describes findings of an investigation of the role of capping molecules in the size growth in the aggregative growth of pre-formed small-sized gold nanoparticles capped with alkanethiolate monolayers toward monodispersed larger sizes. The size controllability depends on the thiolate chain length and concentration in the thermal solution. The size evolution in solution at different concentrations of alkanethiols is analyzed in relation to adsorption isotherms and cohesive energy. The size dependence on thiolate chain length is also analyzed by considering the cohesive energy of the capping molecules, revealing the importance of cohesive energy in the capping structure. Theoretical and experimental comparisons of the surface plasmonic resonance optical properties have also provided new insights into the mechanism, thus enabling the exploitation of size-dependent nanoscale properties.