Detecting stimulated Raman responses of molecules in plasmonic gap using photon induced forces.

We demonstrate the stimulated Raman nanoscopy of a small number of molecules in a plasmonic gap, excited without resonant electronic enhancement, measured using near-field photon-induced forces, eliminating the need for far-field optical detection. We imaged 30 nm diameter gold nanoparticles functionalized with a self-assembled monolayer (SAM) of 4-nitrobenzenethiol (4-NBT) molecules. The maximum number of molecules detected by the gold-coated nano-probe at the position of maximum field enhancement could be fewer than about 42 molecules. The molecules were imaged by vibrating an Atomic Force Microscope (AFM) cantilever on its second flexural eigenmode enabling the tip to be controlled much closer to the sample, thereby improving the detected signal-to-noise ratio when compared to vibrating the cantilever on its first flexural eigenmode. We also demonstrate the implementation of stimulated Raman nanoscopy measured using photon-induced force with non-collinear pump and stimulating beams which could have applications in polarization dependent Raman nanoscopy and spectroscopy and pump-probe nano-spectroscopy particularly involving infrared beam/s. We also discuss using photon induced forces as a technique to sort and select best performing metal coated tips for further use in tip-enhanced experiments.

NF-κB and IRF1 Induce Endogenous Retrovirus K Expression via Interferon-Stimulated Response Elements in Its 5' Long Terminal Repeat.

UNLABELLED: Thousands of endogenous retroviruses (ERV), viral fossils of ancient germ line infections, reside within the human genome. Evidence of ERV activity has been observed widely in both health and disease. While this is most often cited as a bystander effect of cell culture or disease states, it is unclear which signals control ERV transcription. Bioinformatic analysis suggests that the viral promoter of endogenous retrovirus K (ERVK) is responsive to inflammatory transcription factors. Here we show that one reason for ERVK upregulation in amyotrophic lateral sclerosis (ALS) is the presence of functional interferon-stimulated response elements (ISREs) in the viral promoter. Transcription factor overexpression assays revealed independent and synergistic upregulation of ERVK by interferon regulatory factor 1 (IRF1) and NF-κB isoforms. Tumor necrosis factor alpha (TNF-α) and LIGHT cytokine treatments of human astrocytes and neurons enhanced ERVK transcription and protein levels through IRF1 and NF-κB binding to the ISREs. We further show that in ALS brain tissue, neuronal ERVK reactivation is associated with the nuclear translocation of IRF1 and NF-κB isoforms p50 and p65. ERVK overexpression can cause motor neuron pathology in murine models. Our results implicate neuroinflammation as a key trigger of ERVK provirus reactivation in ALS. These molecular mechanisms may also extend to the pathobiology of other ERVK-associated inflammatory diseases, such as cancers, HIV infection, rheumatoid arthritis, and schizophrenia. IMPORTANCE: It has been well established that inflammatory signaling pathways in ALS converge at NF-κB to promote neuronal damage. Our findings suggest that inflammation-driven IRF1 and NF-κB activity promotes ERVK reactivation in neurons of the motor cortex in ALS. Thus, quenching ERVK activity through antiretroviral or immunomodulatory regimens may hinder virus-mediated neuropathology and improve the symptoms of ALS or other ERVK-associated diseases.

TDP-43 regulates endogenous retrovirus-K viral protein accumulation.

The concomitant expression of neuronal TAR DNA binding protein 43 (TDP-43) and human endogenous retrovirus-K (ERVK) is a hallmark of ALS. Since the involvement of TDP-43 in retrovirus replication remains controversial, we sought to evaluate whether TDP-43 exerts an effect on ERVK expression. In this study, TDP-43 bound the ERVK promoter in the context of inflammation or proteasome inhibition, with no effect on ERVK transcription. However, over-expression of ALS-associated aggregating forms of TDP-43, but not wild-type TDP-43, significantly enhanced ERVK viral protein accumulation. Human astrocytes and neurons further demonstrated cell-type specific differences in their ability to express and clear ERVK proteins during inflammation and proteasome inhibition. Astrocytes, but not neurons, were able to clear excess ERVK proteins through stress granule formation and autophagy. In vitro findings were validated in autopsy motor cortex tissue from patients with ALS and neuro-normal controls. We further confirmed marked enhancement of ERVK in cortical neurons of patients with ALS. Despite evidence of enhanced stress granule and autophagic response in ALS cortical neurons, these cells failed to clear excess ERVK protein accumulation. This highlights how multiple cellular pathways, in conjunction with disease-associated mutations, can converge to modulate the expression and clearance of viral gene products from genomic elements such as ERVK. In ALS, ERVK protein aggregation is a novel aspect of TDP-43 misregulation contributing towards the pathology of this neurodegenerative disease.

Sedation versus general anaesthesia for provision of dental treatment to patients younger than 18 years.

BACKGROUND: A significant proportion of children have caries requiring restorations or extractions, and some of these children will not accept this treatment under local anaesthetic. Historically this has been managed by the use of a general anaesthetic in children; however, use of sedation may lead to reduced morbidity and cost. The aim of this review was to compare the efficiency of sedation versus general anaesthesia (GA) for provision of dental treatment to children and adolescents younger than 18 years. This review was originally published in 2009 and was updated in 2012 and again in 2015. OBJECTIVES: We will evaluate morbidity and effectiveness of sedation versus GA for provision of dental treatment to patients younger than 18 years. If data become available, we will analyse the cost-effectiveness of different interventions. If data are not available, we will obtain crude estimates of cost.Morbidity can be defined as 'an undesired result or complication'. For the purposes of this review, 'postoperative morbidity' refers to undesired results or complications such as nausea following a procedure, once the patient had been restored to consciousness and could breathe unaided. 'Intraoperative morbidity' refers to any complications that occur during the procedure that may necessitate action by the anaesthetist or the sedationist, such as respiratory arrest. SEARCH METHODS: In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7); MEDLINE Ovid SP (1950 to July 2015); EMBASE Ovid SP (1974 to July 2015); System for Information on Grey Literature in Europe (SIGLE) (1980 to October July 2012); Latin American & Caribbean Health Sciences Literature (LILACS) (1982 to July 2015); and Institute for Scientific Information (ISI) Web of Science (1945 to July 2015).We also carried out handsearching of relevant journals to July 2015. We imposed no language restriction. SELECTION CRITERIA: We planned to include randomized controlled clinical trials that compared sedative agents versus general anaesthesia in children and adolescents up to 18 years of age undergoing dental treatment. We excluded complex surgical procedures and pseudo-randomized trials. DATA COLLECTION AND ANALYSIS: Two review authors assessed titles and abstracts for inclusion in the review. We recorded information relevant to objectives and outcome measures by using a specially designed 'data extraction form'. We will employ the Grades of Recommendation, Assessment, Development and Evaluation Working Group (GRADE) approach to interpret findings. MAIN RESULTS: In our original review, we identified 16 studies for potential inclusion after searching available databases and screening titles and abstracts. After retrieving full-text studies, we found none to be eligible. We identified no additional studies in the updated search of July 2012. We identified two studies for possible inclusion in the updated search of July 2015; again we found these to be ineligible. AUTHORS' CONCLUSIONS: Randomized controlled studies comparing use of dental general anaesthesia versus sedation are needed to quantify differences such as morbidity and cost.

Structural study of citrate layers on gold nanoparticles: role of intermolecular interactions in stabilizing nanoparticles.

The structure of citrate adlayers on gold nanoparticles (AuNPs) was investigated. Infrared (IR) and X-ray photoelectron spectroscopy (XPS) analyses indicate citrate anions are adsorbed on AuNPs through central carboxylate groups. A unique structure of adsorbed citrate is determined, and a pH-induced structural transition is presented. IR analysis probes dangling dihydrogen anions (H2Citrate(-)) and hydrogen bonding of carboxylic acid groups between adsorbed and dangling citrate anions. A contribution of steric repulsion between citrate layers to particle stability is characterized. Structure-based modeling, which is consistent with scanning tunneling microscopy (STM) and transmission electron microscopy (TEM) images in the literature, suggests organization details relating to the formation of self-assembled layers on (111), (110), and (100) surfaces of AuNPs. Adsorption characteristics of the citrate layer include the interaction between hydrogen-bonded citrate chains, bilayer formation, surface coverage, and chirality. The enthalpic gain from intermolecular interactions and the importance of molecular structure/symmetry on the adsorption are discussed. Combining the enthalpic factor with surface diffusion and adsorption geometry of (1,2)-dicarboxyl fragments on Au(111), H2Citrate(-) anions effectively stabilize the (111) surface of the AuNPs. The detailed understanding of intermolecular interactions in the molecular adlayer provides insight for nanoparticle formation and stabilization. We expect these findings will be relevant for other nanoparticles stabilized by hydroxy carboxylate-based amino acids and have broad implications in NP-based interfacial studies and applications.

Need for subsequent fundoplication after gastrostomy based on patient characteristics.

BACKGROUND: Gastrostomy tube placement is common in children. Many of the conditions associated with need for gastrostomy are also associated with gastroesophageal reflux. It is not clear how many patients without complicated reflux will subsequently require a fundoplication or which conditions increase this risk. Therefore, we performed a two-center review to determine the disease-specific propensity for fundoplication after gastrostomy tube placement. METHODS: The data set was retrospectively collected from two centers from 2000 to 2008. All patients underwent gastrostomy tube placement without fundoplication owing to the surgeon's discernment that fundoplication was not needed at the time. Pearson's correlation was used to evaluate the influence of patient variables and operative approach against the subsequent need for fundoplication. Significance was defined as two-tailed P ≤ 0.01. Logistic regression analysis was used to evaluate independence. RESULTS: A total of 684 patients underwent gastrostomy tube placement only, of which 124 were open, 282 laparoscopic, and 278 endoscopic (percutaneous endoscopic gastrostomy). The mean patient age was 2.9 years. Subsequent fundoplication was performed in 62 patients (9.1%). The mean interval to fundoplication was 20.7 months. Cerebral palsy and anoxic brain injury had the most significant correlation with subsequent fundoplication. These were also independent predictors. The laparoscopic approach had a negative correlation with the subsequent need for fundoplication. CONCLUSIONS: The low incidence of subsequent fundoplication in children who undergo gastrostomy tube placement justifies conservative use of fundoplication in the absence of complicated reflux. Those with cerebral palsy and anoxic brain injury appeared to have the greatest risk of the need for subsequent fundoplication.

Sedation versus general anaesthesia for provision of dental treatment in under 18 year olds.

BACKGROUND: A significant proportion of children have caries requiring restorations or extractions, and some of these children will not accept this treatment under local anaesthetic. Historically this has been managed in children by the use of a general anaesthetic, however use of sedation may lead to reduced morbidity and cost. The aim of this review is to compare the efficiency of sedation versus general anaesthesia for the provision of dental treatment for children and adolescents aged under 18 years.This review was originally published in 2009 and updated in 2012. OBJECTIVES: We evaluated the intra- and postoperative morbidity, effectiveness and cost effectiveness of sedation versus general anaesthesia for the provision of dental treatment for under 18 year olds. SEARCH METHODS: In this updated review we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 7); MEDLINE (Ovid) (1950 to July 2012); EMBASE (Ovid) (1974 to July 2012); System for information on Grey Literature in Europe (SIGLE) (1980 to October 2008), Latin American & Caribbean Health Sciences Literature (LILACS) (1982 to July 2012), and ISI Web of Science (1945 to October 2008). The searches were updated to July 2012. The original search was performed in October 2008.We also carried out handsearching of relevant journals to July 2012. We imposed no language restriction. SELECTION CRITERIA: We planned to include randomized controlled clinical trials of sedative agents compared to general anaesthesia in children and adolescents aged up to 18 years having dental treatment. We excluded complex surgical procedures and pseudo-randomized trials. DATA COLLECTION AND ANALYSIS: Two authors assessed titles and abstracts for inclusion in the review. We recorded information relevant to the objectives and outcome measures in a specially designed 'data extraction form'. MAIN RESULTS: We identified 15 studies for potential inclusion after searching the available databases and screening the titles and abstracts. We identified a further study through personal contacts. Following full text retrieval of the studies, we found none to be eligible for inclusion in this review. AUTHORS' CONCLUSIONS: Randomized controlled studies are required comparing the use of dental general anaesthesia with sedation to quantify differences such as morbidity and cost.

Spectroscopic and microscopic investigation of gold nanoparticle formation: ligand and temperature effects on rate and particle size.

We report a spectroscopic and microscopic investigation of the synthesis of gold nanoparticles (AuNPs) with average sizes of less than 5 nm. The slow reduction and AuNP formation processes that occur by using 9-borabicyclo[3.3.1]nonane (9-BBN) as a reducing agent enabled a time-dependent investigation based on standard UV-vis spectroscopy and transmission electron microscopy (TEM) analyses. This is in contrast to other borohydride-based syntheses of thiolate monolayer protected AuNPs which form particles very rapidly. We investigated the formation of 1-octadecanethiol (ODT) protected AuNPs with average diameters of 1.5-4.3 nm. By studying the progression of nanoparticle formation over time, we find that the nucleation rate and the growth time, which are interlinked with the amount of ODT and the temperature, influence the size and the size dispersion of the AuNPs. High-resolution TEM (HRTEM) analyses also suggest that the nanoparticles are highly single crystalline throughout the synthesis and appear to be formed by a diffusion-controlled Ostwald-ripening growth mechanism.

Brief Report: Analysis of Dental Treatment Provided Under General Anaesthesia for Children and Young Adults with Autistic Spectrum Disorder and Identification of Challenges for Dental Services.

Dental treatment provided under general anaesthesia (DGA) is an expectation for many children and young adults (CYA) diagnosed with Autistic Spectrum Disorder (ASD). Planning and delivery of DGA requires consideration of morbidity and mortality risks and implications for families and healthcare services. One hundred patient records of CYA with special healthcare needs were analysed to examine characteristics and experience of DGA revealing that 79% of CYA had a diagnosis of ASD. Forty-seven percent of CYA diagnosed with ASD had at least one previous hospital admission for DGA. For 24% of this repeat DGA group, the previous DGA was within a two-year period. Results highlight a high rate of DGA and need to investigate more effective primary dental care strategies.

Pro-Inflammatory Signaling Upregulates a Neurotoxic Conotoxin-Like Protein Encrypted Within Human Endogenous Retrovirus-K.

Motor neuron degeneration and spinal cord demyelination are hallmark pathological events in Amyotrophic Lateral Sclerosis (ALS). Endogenous retrovirus-K (ERVK) expression has an established association with ALS neuropathology, with murine modeling pointing to a role for the ERVK envelope (env) gene in disease processes. Here, we describe a novel viral protein cryptically encoded within the ERVK env transcript, which resembles two distinct cysteine-rich neurotoxic proteins: conotoxin proteins found in marine snails and the Human Immunodeficiency Virus (HIV) Tat protein. Consistent with Nuclear factor-kappa B (NF-κB)-induced retrotransposon expression, the ERVK conotoxin-like protein (CTXLP) is induced by inflammatory signaling. CTXLP is found in the nucleus, impacting innate immune gene expression and NF-κB p65 activity. Using human autopsy specimens from patients with ALS, we further showcase CTXLP expression in degenerating motor cortex and spinal cord tissues, concomitant with inflammation linked pathways, including enhancement of necroptosis marker mixed lineage kinase domain-like (MLKL) protein and oligodendrocyte maturation/myelination inhibitor Nogo-A. These findings identify CTXLP as a novel ERVK protein product, which may act as an effector in ALS neuropathology.

Active Plasmonics and Active Chiral Plasmonics through Orientation-Dependent Multipolar Interactions.

While most active plasmonic efforts focus on responsive metamaterials to modulate optical response, we present a simple alternative based on applied orientation control that can likely be implemented for many passive plasmonic materials. Passive plasmonic motifs are simpler to prepare but cannot be altered postfabrication. We show that such systems can be easily manipulated through substrate orientation control to generate both active plasmonic and active chiral plasmonic responses. Using gold nanocrescents as our model platform, we demonstrate tuning of optical extinction from -21% to +36% at oblique incidence relative to normal incidence. Variation of substrate orientation in relation to incident polarization is also demonstrated to controllably switch chiroptical handedness (e.g., Δg = ± 0.55). These active plasmonic responses arise from the multipolar character of resonant modes. In particular, we correlate magnetoelectric and dipole-quadrupole polarizabilities with different light-matter orientation-dependence in both near- and far-field localized surface plasmon activity. Additionally, the attribution of far-field optical response to higher-order multipoles highlights the sensitivity offered by these orientation-dependent characterization techniques to probe the influence of localized electromagnetic field gradients on a plasmonic response. The sensitivity afforded by orientation-dependent optical characterization is further observed by the manifestation in both plasmon and chiral plasmon responses of unpredicted structural nanocrescent variance (e.g., left- and right-tip asymmetry) not physically resolved through topographical imaging.

Silver nanocrescents with infrared plasmonic properties as tunable substrates for surface enhanced infrared absorption spectroscopy.

We exploit the unique infrared plasmonic properties of silver nanocrescents (AgNCs) in preparing tunable substrates for surface enhanced infrared absorption (SEIRA) spectroscopy. Fabrication provides good control over the crescents' structural properties which enables tuning of the localized surface plasmon resonances (LSPRs) from the visible through the infrared (IR) regions of the spectrum. Using AgNCs as uniquely tunable IR LSPR substrates, we demonstrate the impact of spectral tuning on maximizing SEIRA signal enhancements measured for adsorbed alkylthiolates. The AgNCs demonstrate the largest reported area-normalized SEIRA signal enhancements which increase from 7,700 to 46,000 depending on the relative positions of the AgNC's LSPR frequency and the molecular vibration frequency. The SEIRA enhancement increases and the absorption band line shape becomes more asymmetric as the AgNCs' LSPR frequency overlaps more extensively with the frequency of the probed molecular vibration. The tunability of the LSPR properties will enable fundamental SEIRA studies and the development of optimized SEIRA substrates for detection and identification of molecular adsorbates.

In situ microarray fabrication and analysis using a microfluidic flow cell array integrated with surface plasmon resonance microscopy.

Surface Plasmon Resonance Microscopy (SPRM) is a promising label-free analytical tool for the real-time study of biomolecule interactions in a microarray format. However, flow cell design and microarray fabrication have hindered throughput and limited applications of SPRM. Here we report the integration of a microfluidic flow cell array (MFCA) with SPRM enabling in situ microarray fabrication and multichannel analysis of biomolecule probe-target interactions. We demonstrate the use of the MFCA for delivery of sample solutions with continuous flow in 24 channels in parallel for rapid microarray creation and binding analysis while using SPRM for real-time monitoring of these processes. Label-free measurement of antibody-antibody interactions demonstrates the capabilities of the integrated MFCA-SPRM system and establishes the first steps of the development of a high-throughput, label-free immunogenicity assay. After in situ probe antibody immobilization, target antibody binding was monitored in real time in 24 channels simultaneously. The limit of detection for this particular antibody pair is 80 ng/mL which is approximately 6 times lower than the industry recommended immunogenicity assay detection limit. The integrated MFCA-SPRM system is a powerful and versatile combination for a range of array-based analyses, including biomarker screening and drug discovery.

One-step synthesis of phosphine-stabilized gold nanoparticles using the mild reducing agent 9-BBN.

A simple method to synthesize phosphine-stabilized gold nanoparticles (AuNPs) of narrow size dispersion using the mild reducing agent 9-borabicyclo[3.3.1]nonane (9-BBN) is described. The methodology produces particles 1.2-2.8 nm in size depending on the reaction conditions and the phosphine ligand used. The phosphine-stabilized AuNPs exhibit size dependent localized surface plasmon resonance (LSPR) behavior as measured by UV-visible spectroscopy. (31)P NMR spectroscopy analysis of triphenylphosphine-AuNPs (TPP-AuNPs) shows a peak shift to 63.0 ppm compared to pure TPP at -5.4 ppm which is attributed to adsorption of TPP on the AuNP surface. Synthesis of trioctylphosphine-stabilized AuNPs demonstrates the versatility of the 9-BBN-based method. We present initial investigations of using TPP-AuNPs as precursor materials for nanoparticles functionalized with other ligands through ligand exchange reactions with dodecanethiol (DDT) and 11-mercaptoundecanoic acid (MUA).

Sedation versus general anaesthesia for provision of dental treatment in under 18 year olds.

BACKGROUND: A significant proportion of children have caries requiring restorations or extractions, and some of these children will not accept this treatment under local anaesthetic. Historically this has been managed in children by use of a general anaesthetic; however use of sedation may lead to reduced morbidity and cost. The aim of this review is to compare the efficiency of sedation versus general anaesthesia for the provision of dental treatment for children and adolescents under 18 years. OBJECTIVES: We evaluated the intra- and post-operative morbidity, effectiveness and cost effectiveness of sedation versus general anaesthesia for the provision of dental treatment for under 18 year olds. SEARCH STRATEGY: We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library; Issue 4, 2008); MEDLINE (OVID) (1950 to October Week 2, 2008); EMBASE (OVID) (1974 to Week 42, 2008); System for information on Grey Literature in Europe (SIGLE) (1980 to October 2008), Latin American & Caribbean Health Sciences Literature (LILACS) (1982 to October 2008), ISI Web of Science (1945 to October 2008).We also carried out handsearching of relevant journals. There was no language restriction. SELECTION CRITERIA: We included randomized controlled clinical trials of sedative agents compared to general anaesthesia in children and adolescents aged up to 18 years having dental treatment. We excluded complex surgical procedures and pseudo-randomized trials. DATA COLLECTION AND ANALYSIS: Two authors assessed titles and abstracts for inclusion in the review. We recorded information relevant to the objectives and outcome measures into a specially designed 'data extraction form'. MAIN RESULTS: We identified 15 studies for potential inclusion after searching the available databases and screening the titles and abstracts. We identified a further study through personal contacts. Following full text retrieval of the studies, we found none to be eligible AUTHORS' CONCLUSIONS: Randomized controlled studies comparing the use of dental general anaesthesia with sedation to quantify differences such as morbidity and cost are required.

Parent-reported experience of using a real-time text messaging service for dental appointments for children and young people with autism spectrum conditions: A pilot study.

INTRODUCTION: Children and young people (CYP) with autism spectrum conditions (ASCs) and their parents/carers find dental appointments stressful. Consultation with parents of CYP with ASC identified time spent in dental waiting areas as contributing to dental anxiety. Parents proposed waiting outside the dental practice until the clinician was ready could help mitigate anxiety. AIMS: To evaluate a real-time text messaging service (RTMS) to improve dental attendance experience for CYP with ASC. METHODS: An RTMS was developed for use in the dental clinic. Parents/carers of 17 CYP with ASC (4 to 20 years) attending a Special Care Dental service were invited to share their dental experience and the impact of using the RTMS. RESULTS: Parent experience suggests that time in waiting areas can increase anxiety in CYP with ASC. All parents viewed the RTMS as having a positive impact on CYP dental attendance experience. The majority believed that it reduced anxiety and enabled CYP to be more accepting of dental treatment. DISCUSSION: Many CYP with ASC have dental anxiety exacerbated by the use of waiting areas. Findings demonstrate the importance of considering and developing a range of approaches that respond to the needs of CYP with ASC and their families to improve dental attendance experience.

Three paediatric patients with oral self-mutilation--a report.

UNLABELLED: Oral self-mutilation, although thought to be uncommon, is quite widespread. Practitioners should carefully consider self-mutilation as part of their differential diagnosis in unexplainable oral conditions. We report three paediatric cases of oral self-mutilation. CLINICAL RELEVANCE: Deliberate self-mutilation, although practised in certain parts of the world, is relatively rare in western cultures. Although uncommon, Altom and DiAngelis believe oral self-mutilation is probably more widespread than is recognized. Self-mutilation of the oral soft and hard tissues can include gingival, mucosal and periodontal damage, glossectomy, auto extraction and the insertion of foreign bodies.

Strong resistance of citrate anions on metal nanoparticles to desorption under thiol functionalization.

Thiols are widely utilized to functionalize metal nanoparticles, including ubiquitous citrate-stabilized gold nanoparticles (AuNPs), for fundamental studies and biomedical applications. For more than two decades, citrate-to-thiol ligand exchange has been used to introduce functionality to AuNPs in the 5-100 nm size regime. Contrary to conventional assumptions about the completion of ligand exchange processes and formation of a uniform self-assembled monolayer (SAM) on the NP surface, coadsorption of thiols with preadsorbed citrates as a mixed layer on AuNPs is demonstrated. Hydrogen bonding between carboxyl moieties primarily is attributed to the strong adsorption of citrate, leading to the formation of a stabilized network that is challenging to displace. In these studies, adsorbed citrates, probed by Fourier transform infrared and X-ray photoelectron spectroscopy (XPS) analyses, remain on the surface following thiol addition to the AuNPs, whereas acetoacetate anions are desorbed. XPS quantitative analysis indicates that the surface density of alkyl and aryl thiolates for AuNPs with an average diameter of ∼40 nm is 50-65% of the value of a close-packed SAM on Au(111). We present a detailed citrate/thiolate coadsorption model that describes this final mixed surface composition. Intermolecular interactions between weakly coordinated oxyanions, such as polyprotic carboxylic acids, can lead to enhanced stability of the metal-ligand interactions, and this needs to be considered in the surface modification of metal nanoparticles by thiols or other anchor groups.

Telementoring: the surgical tool of the future.

With decreased resident experience during training and the constant evolution of new surgical techniques, surgeons are at risk for complications during the early part of the learning curve. Mentorship by experienced surgeons may mitigate these complications. The availability of such advanced telepresence technology makes it logical that this will be used as part of the model to proctor, mentor, and train practicing surgeons. Here, we review the current state of telementoring.