Utilization of coupled eigenmodes in Akiyama atomic force microscopy probes for bimodal multifrequency sensing.

Akiyama atomic force microscopy probes represent a unique means of combining several of the desirable properties of tuning fork and cantilever probe designs. As a hybridized mechanical resonator, the vibrational characteristics of Akiyama probes result from a complex coupling between the intrinsic vibrational eigenmodes of its constituent tuning fork and bridging cantilever components. Through a combination of finite element analysis modeling and experimental measurements of the thermal vibrations of Akiyama probes we identify a complex series of vibrational eigenmodes and measure their frequencies, quality factors, and spring constants. We then demonstrate the viability of Akiyama probes to perform bimodal multi-frequency force sensing by performing a multimodal measurement of a surface's nanoscale photothermal response using photo-induced force microscopy imaging techniques. Further performing a parametric search over alternative Akiyama probe geometries, we propose two modified probe designs to enhance the capability of Akiyama probes to perform sensitive bimodal multifrequency force sensing measurements.

Space-Time Quantum Metasurfaces.

Metasurfaces have recently entered the realm of quantum photonics, enabling manipulation of quantum light using a compact nanophotonic platform. Realizing the full potential of metasurfaces at the deepest quantum level requires the ability to tune coherent light-matter interactions continuously in space and time. Here, we introduce the concept of space-time quantum metasurfaces for arbitrary control of the spectral, spatial, and spin properties of nonclassical light using a compact photonic platform. We show that space-time quantum metasurfaces allow on-demand tailoring of entanglement among all degrees of freedom of a single photon. We also show that spatiotemporal modulation induces asymmetry at the fundamental level of quantum fluctuations, resulting in the generation of steered and vortex photon pairs out of vacuum. Space-time quantum metasurfaces have the potential to enable novel photonic functionalities, such as encoding quantum information into high-dimensional color qudits using designer modulation protocols, sculpting multispectral and multispatial modes in spontaneous emission, and generating reconfigurable hyperentanglement for high-capacity quantum communications.

Near-Field Radiative Heat Transfer Eigenmodes.

The near-field electromagnetic interaction between nanoscale objects produces enhanced radiative heat transfer that can greatly surpass the limits established by far-field blackbody radiation. Here, we present a theoretical framework to describe the temporal dynamics of the radiative heat transfer in ensembles of nanostructures, which is based on the use of an eigenmode expansion of the equations that govern this process. Using this formalism, we identify the fundamental principles that determine the thermalization of collections of nanostructures, revealing general but often unintuitive dynamics. Our results provide an elegant and precise approach to efficiently analyze the temporal dynamics of the near-field radiative heat transfer in systems containing a large number of nanoparticles.

Late diagnosis, delayed presentation and late presentation among persons enrolled in a clinical HIV cohort in Ontario, Canada (1999-2013).

OBJECTIVES: Timely HIV diagnosis and presentation to medical care are important for treatment and prevention. Our objective was to measure late diagnosis, delayed presentation and late presentation among individuals in the Ontario HIV Treatment Network Cohort Study (OCS) who were newly diagnosed in Ontario. METHODS: The OCS is a multi-site clinical cohort study of people living with HIV in Ontario, Canada. We measured prevalence of late diagnosis [CD4 count < 350 cells/µL or an AIDS-defining condition (ADC) within 3 months of HIV diagnosis], delayed presentation (≥ 3 months from HIV diagnosis to presentation to care), and late presentation (CD4 count < 350 cells/µL or ADC within 3 months of presentation). We identified characteristics associated with these outcomes and explored their overlap. RESULTS: A total of 1819 OCS participants were newly diagnosed in Ontario from 1999 to 2013. Late diagnosis (53.0%) and presentation (54.0%) were common, and a quarter (23.1%) of participants were delayed presenters. In multivariable models, the participants of delayed presentation decreased over calendar time, but that of late diagnosis/presentation did not. Late diagnosis contributed to the majority (> 87%) of late presentation, and the prevalence of delayed presentation was similar among those diagnosed late versus early (13.4 versus 13.4%, respectively; P = 0.99). Characteristics associated with higher odds of late diagnosis/presentation in multivariable analyses included older age at diagnosis/presentation; African, Caribbean and Black race/ethnicity; Indigenous race/ethnicity; female sex; and being a male who did not report sex with men. There were lower odds of late diagnosis/presentation among participants who had ever injected drugs. In contrast, delayed presentation risk factors included younger age at diagnosis and having ever injected drugs. CONCLUSIONS: Late presentation is common in Ontario, as it is in other high-income countries. Our findings suggest that efforts to reduce late presentation should focus on facilitating earlier diagnosis for the populations identified in this analysis.

Diet and lupus: what do the patients think?

OBJECTIVES: Cardiovascular disease is the leading cause of mortality in patients with systemic lupus erythematosus. Therefore, using diet to control blood lipid levels and modify cardiovascular disease risk could be a promising therapeutic strategy to control disease symptoms. The primary objective of this study was to learn about systemic lupus erythematosus patient experiences with diet, including their opinion on considering diet as a therapeutic option. The secondary objective was to obtain this information in a cost- and time-effective manner. METHODS: A lay summary and a 15-question diet-based online survey were publicly available for 3 weeks. Social media was used to promote the survey through relevant charities, hospitals and research groups. RESULTS: A total of 300 responses were received, 284 from patients with systemic lupus erythematosus. Patients reported that there was a lack of clinical counselling regarding diet, with only 24% stating their doctor had spoken to them about diet. Despite this, 100% of patients stated they would change their diet if they knew it would help their symptoms and 83% would take part in a future diet-based clinical trial. Text analysis of patient research suggestions identified a particular interest in using diet to treat fatigue and manage disease flares. CONCLUSIONS: This project successfully gathered patient information regarding diet and systemic lupus erythematosus over a short timeframe using an anonymous social media platform. The survey provided evidence that patients support further research and potential diet intervention studies investigating the effect of diet on the symptoms of systemic lupus erythematosus.

High-Temperature Refractory Metasurfaces for Solar Thermophotovoltaic Energy Harvesting.

Solar energy promises a viable solution to meet the ever-increasing power demand by providing a clean, renewable energy alternative to fossil fuels. For solar thermophotovoltaics (STPV), high-temperature absorbers and emitters with strong spectral selectivity are imperative to efficiently couple solar radiation into photovoltaic cells. Here, we demonstrate refractory metasurfaces for STPV with tailored absorptance and emittance characterized by in situ high-temperature measurements, featuring thermal stability up to at least 1200 °C. Our tungsten-based metasurface absorbers have close-to-unity absorption from visible to near-infrared and strongly suppressed emission at longer wavelengths, while our metasurface emitters provide wavelength-selective emission spectrally matched to the band-edge of InGaAsSb photovoltaic cells. The projected overall STPV efficiency is as high as 18% when a fully integrated absorber/emitter metasurface structure is employed, which is comparable to the efficiencies of the best currently available commercial single-junction PV cells and can be further improved to potentially exceed those in mainstream photovoltaic technologies. Our work opens a path forward for high-performance STPV systems based on refractory metasurface structures.

Acetylcholinesterase inhibition and antimicrobial activity of hydroxyl amides synthesized from natural products derivatives.

Thirteen natural products derivatives of hydroxyl amide class, three described for the first time, were synthesized by reaction of three indole acids and 3,4,5-trimethoxybenzoic acid with six different amino alcohols in the presence of triphenylphosphine and N-bromosuccinimide. The derivatives were tested against the Gram (+) bacteria Staphylococcus aureus and Bacillus cereus, Gram (-) Pseudomonas aeruginosa and Escherichia coli, besides the yeast Candida albicans. One of the compounds (7) was selectively active against C. albicans (91.3 ± 0.49% inhibition) showing a great potential as a new drug lead, since it was more active than the positive control, miconazole (88.7 ± 2.41% inhibition). Regarding bacterial inhibition, compounds demonstrated mild activity, but inhibition of compounds 9, 10 and 13 towards E. coli is of interest since it is difficult to find drugs selectively active against Gram (-) bacteria. Most of the compounds were very active in the acetylcholinesterase inhibition assay. Compound 7 was again the most active (93.2 ± 4.47%), being more potent than the control galantamine (90.3 ± 0.45%). The most active gallic acid derivatives, compounds 3, 7 and 8 have in common, besides gallic acid skeleton, a (CH2)2OH group, which may be one of the structural requirements for AChE inhibition.

The Anatomical Society core regional anatomy syllabus for undergraduate medicine.

The Anatomical Society's core syllabus for anatomy (2003 and later refined in 2007) set out a series of learning outcomes that an individual medical student should achieve on graduation. The core syllabus, with 182 learning outcomes grouped in body regions, referenced in the General Medical Council's Teaching Tomorrow's Doctors, was open to criticism on the grounds that the learning outcomes were generated by a relatively small group of anatomists, albeit some of whom were clinically qualified. We have therefore used a modified Delphi technique to seek a wider consensus. A Delphi panel was constructed involving 'experts' (n = 39). The revised core syllabus of 156 learning outcomes presented here is applicable to all medical programmes and may be used by curriculum planners, teachers and students alike in addressing the perennial question: 'What do I need to know ?'

Spatially Resolved Near Field Spectroscopy of Vibrational Polaritons at the Small N Limit.

Vibrational polaritons, which have been primarily studied in Fabry-Pérot cavities with a large number of molecules (N ∼ 106-1010) coupled to the resonator mode, exhibit various experimentally observed effects on chemical reactions. However, the exact mechanism is elusively understood from the theoretical side, as the large number of molecules involved in an experimental strong coupling condition cannot be represented completely in simulations. This discrepancy between theory and experiment arises from computational descriptions of polariton systems typically being limited to only a few molecules, thus failing to represent the experimental conditions adequately. To address this mismatch, we used surface phonon polariton (SPhP) resonators as an alternative platform for vibrational strong coupling. SPhPs exhibit strong electromagnetic confinement on the surface and thus allow for coupling to a small number of molecules. As a result, this platform can enhance nonlinearity and slow down relaxation to the dark modes. In this study, we fabricated a pillar-shaped quartz resonator and then coated it with a thin layer of cobalt phthalocyanine (CoPc). By employing scattering-type scanning near-field optical microscopy (s-SNOM), we spatially investigated the dependency of vibrational strong coupling on the spatially varying electromagnetic field strength and demonstrated strong coupling with 38,000 molecules only-reaching to the small N limit. Through s-SNOM analysis, we found that strong coupling was observed primarily on the edge of the quartz pillar and the apex of the s-SNOM tip, where the maximum field enhancement occurs. In contrast, a weak resonance signal and lack of coupling were observed closer to the center of the pillar. This work demonstrates the importance of spatially resolved polariton systems in nanophotonic platforms and lays a foundation to explore polariton chemistry and chemical dynamics at the small N limit-one step closer to reconcile with high-level quantum calculations.

Nonlinear dynamics of topological Dirac fermions in 2D spin-orbit coupled materials.

The graphene family materials are two-dimensional staggered monolayers with a gapped energy band structure due to intrinsic spin-orbit coupling. The mass gaps in these materials can be manipulated on-demand via biasing with a static electric field, an off-resonance circularly polarized laser, or an exchange interaction field, allowing the monolayer to be driven through a multitude of topological phase transitions. We investigate the dynamics of spin-orbit coupled graphene family materials to unveil topological phase transition fingerprints embedded in the nonlinear regime and show how these signatures manifest in the nonlinear Kerr effect and in third-harmonic generation processes. We show that the resonant nonlinear spectral response of topological fermions can be traced to specific Dirac cones in these materials, enabling characterization of topological invariants in any phase by detecting the cross-polarized component of the electromagnetic field. By shedding light on the unique processes involved in harmonic generation via topological phenomena our findings open an encouraging path towards the development of novel nonlinear systems based on two-dimensional semiconductors of the graphene family.

Surface-wave-assisted nonreciprocity in spatio-temporally modulated metasurfaces.

Emerging photonic functionalities are mostly governed by the fundamental principle of Lorentz reciprocity. Lifting the constraints imposed by this principle could circumvent deleterious effects that limit the performance of photonic systems. Most efforts to date have been limited to waveguide platforms. Here, we propose and experimentally demonstrate a spatio-temporally modulated metasurface capable of complete violation of Lorentz reciprocity by reflecting an incident beam into far-field radiation in forward scattering, but into near-field surface waves in reverse scattering. These observations are shown both in nonreciprocal beam steering and nonreciprocal focusing. We also demonstrate nonreciprocal behavior of propagative-only waves in the frequency- and momentum-domains, and simultaneously in both. We develop a generalized Bloch-Floquet theory which offers physical insights into Lorentz nonreciprocity for arbitrary spatial phase gradients, and its predictions are in excellent agreement with experiments. Our work opens exciting opportunities in applications where free-space nonreciprocal wave propagation is desired.

Familial vasopressin-sensitive ACTH-independent macronodular adrenal hyperplasia (VPs-AIMAH): clinical studies of three kindreds.

OBJECTIVE: Cushing's syndrome due to familial ACTH-independent macronodular adrenal hyperplasia (AIMAH) has been reported in small kindreds. In vasopressin-sensitive AIMAH (VPs-AIMAH), VP stimulates an aberrant, ACTH-independent increase in cortisol. The aims of this study were to (i) delineate the preclinical phenotype of VPs-AIMAH in a three-generation kindred (AIMAH-01) and two smaller kindreds (AIMAH-02 and AIMAH-03) and (ii) investigate the aetiology of VP sensitivity in AIMAH-01. DESIGN: Clinical studies of three kindreds for adrenal tumours or early Cushing's and molecular studies of adrenal tumours (AIMAH-01). PATIENTS: Thirty-three individuals, from three kindreds, were screened for perturbations of the hypothalamic-pituitary-adrenal axis or adrenal tumours. MEASUREMENTS: Patients underwent clinical, biochemical and adrenal imaging investigations. Evaluation included low-dose (1 IU/70 kg) VP stimulation. Adrenal VP receptor (AVPR1A, AVPR1B, AVPR2) expression (AIMAH-01) was assessed using RT-PCR and immunohistochemistry (IHC). IHC for VP was also performed. RESULTS: AIMAH-01 had three siblings with Cushing's, and four individuals with suppressed ACTH/aberrant VP responses and/or adrenal nodules. In AIMAH-02, a father and son were affected. AIMAH-03 had three siblings with Cushing's. RT-PCR showed adrenal overexpression of AVPR1A and AVPR1B. IHC detected AVPR1A. The adrenal tumour from one patient also stained weakly for VP and AVPR2. CONCLUSION: Adrenal nodules, suppressed ACTH and increased VP sensitivity may represent preclinical disease, allowing early detection, and treatment, of affected individuals. In AIMAH-01, increased VP sensitivity may be due to adrenal VP receptor overexpression. In these kindreds, VPs-AIMAH is familial, and autosomal dominant inheritance is most likely.

Low O6-methylguanine-DNA methyltransferase (MGMT) expression and response to temozolomide in aggressive pituitary tumours.

CONTEXT: Recent case reports detail the successful use of temozolomide in the management of aggressive pituitary tumours. O(6)-methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein that counteracts the effect of temozolomide. OBJECTIVE: To study MGMT expression in pituitary tumours and consider whether MGMT expression is associated with response to temozolomide therapy in aggressive pituitary tumours. PATIENTS: We report two patients with aggressive pituitary tumours treated with temozolomide, one who responded to temozolomide and the other who did not. MGMT expression was assessed in a further 88 archived pituitary tumour samples. DESIGN: MGMT expression was assessed by immunohistochemistry. MGMT promoter methylation was studied by methylation-specific polymerase chain reaction (MSP), sequencing of MGMT was performed and loss of heterozygosity (LOH) analysis undertaken. RESULTS: Low MGMT expression and MGMT promoter methylation were found in the pituitary tumour of the patient who responded to temozolomide. Conversely, high MGMT expression was seen in the patient demonstrating a poor response to temozolomide. Eleven out of 88 archived tumour samples (13%) had low MGMT expression. Prolactinomas were more likely to have low MGMT expression compared with other pituitary tumour subtypes (P < 0.001). There was no significant difference in MGMT expression between invasive and noninvasive tumours, or between recurrent and nonrecurrent tumours. A significant inverse correlation was found between MGMT expression and promoter methylation (P = 0.012). CONCLUSION: MGMT expression as assessed by immunohistochemistry may predict response to temozolomide therapy in patients with aggressive pituitary tumours. MGMT promoter methylation is likely to explain low MGMT expression in some, but not all, pituitary tumours.

Fluorescent choleretic and cholestatic bile salts take different paths across the hepatocyte: transcytosis of glycolithocholate leads to an extensive redistribution of annexin II.

We have used fluorescent derivatives of the choleretic bile salts cholate and chenodeoxycholate, the cholestatic salt lithocholate, and the therapeutic agent ursodeoxycholate to visualize distinct routes of transport across the hepatocyte and delivery to the canalicular vacuole of isolated hepatocyte couplets. The cholate and chenodeoxycholate derivatives produced homogeneous intracellular fluorescence and were rapidly transported to the vacuole, while the lithocholate analogue accumulated more slowly in the canalicular vacuole and gave rise to punctate fluorescence within the cell. Fluorescent ursodeoxycholate showed punctate intracellular fluorescence against a high uniform background indicating use of both pathways. Inhibition of vesicular transport by treatment with colchicine and Brefeldin A had no effect on the uptake of any of the compounds used, but it dramatically impaired delivery of both the lithocholate and the ursodeoxycholate derivatives to the canalicular vacuole. We conclude that while the chenodeoxycholate and cholate analogues traverse the hepatocyte by a cytoplasmic route, lithocholate and ursodeoxycholate analogues are transported by vesicle-mediated transcytosis. Treatment of couplets with glycine derivatives of lithocholate and ursodeoxycholate, but not cholate or chenodeoxycholate, led to a marked relocalization of annexin II, which initially became concentrated at the basolateral membrane, then moved to a perinuclear distribution and finally to the apical membrane as the incubation progressed. This suggests that lithocholate and ursodeoxycholate treatment leads to a rapid induction of transcytosis and that annexin II exchange occurs upon membrane fusion at all stages of the hepatocyte transcytotic pathway. These results indicate that isolated hepatocyte couplets may provide an inducible model system for the study of vesicle-mediated transcytosis.

Highly Plasmonic Titanium Nitride by Room-Temperature Sputtering.

Titanium nitride (TiN) has recently emerged as an attractive alternative material for plasmonics. However, the typical high-temperature deposition of plasmonic TiN using either sputtering or atomic layer deposition has greatly limited its potential applications and prevented its integration into existing CMOS device architectures. Here, we demonstrate highly plasmonic TiN thin films and nanostructures by a room-temperature, low-power, and bias-free reactive sputtering process. We investigate the optical properties of the TiN films and their dependence on the sputtering conditions and substrate materials. We find that our TiN possesses one of the largest negative values of the real part of the dielectric function as compared to all other plasmonic TiN films reported to date. Two-dimensional periodic arrays of TiN nanodisks are then fabricated, from which we validate that strong plasmonic resonances are supported. Our room-temperature deposition process can allow for fabricating complex plasmonic TiN nanostructures and be integrated into the fabrication of existing CMOS-based photonic devices to enhance their performance and functionalities.

Guided self-help to manage binge eating in a dietetic-led community weight management service.

An estimated 30% of patients accessing community weight management services experience symptoms of binge eating disorder (BED). Guided self-help (GSH) is the recommended first line of treatment for BED. This study is a preliminary investigation into the effectiveness of GSH delivered by dietitians for patients with binge eating within a weight management service and a consideration of the association between wellbeing, therapeutic relationship and outcomes. The study was conducted as a single group, pre- and post-intervention study with 24 patients reporting symptoms of binge eating who completed the self-help manual with guidance from a trained community dietitian. Primary outcomes were eating disorder psychopathology and behaviours (Eating Disorder Evaluation Questionnaire), depression and anxiety. Principle results showed a significant reduction on all subscales of eating disorder psychopathology, anxiety and depression. There was a reduction in loss of control over eating but the 40% reduction in binge episodes was not statistically significant. Mid-treatment sessional ratings were positively associated with outcome. In conclusion, the GSH intervention was appropriate for dietitian delivery to patients with obesity and binge eating behaviour. This research indicates potential for other dietetic-led weight management services to deliver such interventions and support patients with binge eating accessing their service.

Human antibodies with sub-nanomolar affinities isolated from a large non-immunized phage display library.

To generate a stable resource from which high affinity human antibodies to any given antigen can be rapidly isolated, functional V-gene segments from 43 non-immunized human donors were used to construct a repertoire of 1.4 x 10(10) single-chain Fv (scFv) fragments displayed on the surface of phage. Fragments were cloned in a phagemid vector, enabling both phage displayed and soluble scFv to be produced without subcloning. A hexahistidine tag has been incorporated to allow rapid purification of scFv by nickel chelate chromatography. This library format reduces the time needed to isolate monoclonal antibody fragments to under two weeks. All of the measured binding affinities show a Kd < 10 nM and off-rates of 10(-3) to 10(-4) s-1, properties usually associated with antibodies from a secondary immune response. The best of these scFvs, an anti-fluorescein antibody (0.3 nM) and an antibody directed against the hapten DTPA (0.8 nM), are the first antibodies with subnanomolar binding affinities to be isolated from a naive library. Antibodies to doxorubicin, which is both immunosuppressive and toxic, as well as a high affinity and high specificity antibody to the steroid hormone oestradiol have been isolated. This work shows that conventional hybridoma technology may be superseded by large phage libraries that are proving to be a stable and reliable source of specific, high affinity human monoclonal antibodies.

Comparison of secretory IgA and IgG isotype levels in palatal secretions of denture stomatitis patients with denture wearers having clinically healthy palates.

Denture stomatitis is an inflammatory condition affecting palatal mucosa covered by a denture. Aetiology is multifactorial involving poor hygiene, constant denture wearing, trauma and colonisation by Candida species. In inflamed tissues raised levels of albumin, IgG isotypes and secretory IgA (sIgA) would be expected. SIgA is a major component of the protective immunological response to mucosal injection. Palatal secretions of 21 patients with denture stomatitis and 22 denture wearing patients with clinically healthy palates were analysed for albumin, IgG isotypes and sIgA levels. Albumin and IgG isotype levels were found to be higher in denture stomatitis patients compared with healthy palate patients. Unexpectedly, SIgA levels were found to be significantly (p<0.05) lower in denture stomatitis patients compared with healthy palate patients.

Can intra-operative fluorescence play a significant role in hepatobiliary surgery?

Liver resection remains the cornerstone of curative treatment for hepatocellular carcinoma and colorectal cancer liver metastases. Its success is dependent upon the extent of resection achieved. To this end, intra-operative imaging techniques have been experimented with to aid the surgeon. Fluorescence guided surgery (FGS) utilises the properties of near infrared light emitting molecules to identify malignant tissue, enabling the surgeon to maximise resection of diseased tissue and minimise collateral damage. Data from early trials showed increased superficial lesion detection when using fluorescence to guide liver resection. However, with far greater tissue penetration, intra-operative ultrasound (IOUS) remains the gold-standard intra-operative imaging modality. Subsequent trials have shown that the concomitant use of both FGS and IOUS may increase tumour detection rates intra-operatively. This review provides a comprehensive analysis of the most compelling evidence regarding fluorescence in hepatobiliary surgery and addresses the challenges faced introducing it into common practice.