Ultrafast generation and control of an electron vortex beam via chiral plasmonic near fields.

Vortex-carrying matter waves, such as chiral electron beams, are of significant interest in both applied and fundamental science. Continuous-wave electron vortex beams are commonly prepared via passive phase masks imprinting a transverse phase modulation on the electron's wavefunction. Here, we show that femtosecond chiral plasmonic near fields enable the generation and dynamic control on the ultrafast timescale of an electron vortex beam. The vortex structure of the resulting electron wavepacket is probed in both real and reciprocal space using ultrafast transmission electron microscopy. This method offers a high degree of scalability to small length scales and a highly efficient manipulation of the electron vorticity with attosecond precision. Besides the direct implications in the investigation of nanoscale ultrafast processes in which chirality plays a major role, we further discuss the perspectives of using this technique to shape the wavefunction of charged composite particles, such as protons, and how it can be used to probe their internal structure.

Near-field circular polarization probed by chiral polyfluorene.

We demonstrate that a high degree of circular polarization can be delivered to the near field (NF) of an aperture at the apex of hollow-pyramid probes for scanning optical microscopy. This result is achieved by analyzing the dichroic properties of an annealed thin polymer film containing a chiral polyfluorene derivative, placed in close proximity to the optical probe. We also prove that the degree of circular polarization in the probe NF does not depend in a significant way on the shape of the aperture, at variance with the far-field behavior. These results demonstrate the feasibility of nano-optics applications exploiting circularly polarized NFs.

Experimental demonstration of the optical Zeno effect by scanning tunneling optical microscopy.

An experimental demonstration of a classical analogue of the quantum Zeno effect for light waves propagating in engineered arrays of tunneling-coupled optical waveguides is reported. Quantitative mapping of the flow of light, based on scanning tunneling optical microscopy, clearly demonstrates that the escape dynamics of light in an optical waveguide side-coupled to a tight-binding continuum is slowed down when projective measurements, mimicked by sequential interruptions of the decay, are performed on the system.

Mapping local field enhancements at nanostructured metal surfaces by second-harmonic generation induced in the near field.

We report on an aperture scanning near-field optical microscope in which femtosecond pulses are coupled to a hollow-pyramid aperture sensor. Such probe displays high throughput and preserves pulse duration and polarization, enabling the achievement of sufficiently high peak power in the near field to perform nonlinear optics on the nanoscale. We use the system to observe the nonlinear optical response of nanostructured metal surfaces with sub-100-nm spatial resolution. We study second-harmonic generation from gold nanoparticles both isolated and in high-density patterns, highlighting a strong dependence of the generation efficiency on the shape and on the fine structure of the nanoemitter. In particular, we present results on closely packed gold triangles as well as on nanoellipsoids with different local surface plasmon resonances.

A simple method for producing flattened atomic force microscopy tips.

We describe a simple and reliable procedure for obtaining a flat plateau on top of standard silicon nitride atomic force microscopy tips by scanning them over the focus of a high-numerical-aperture objective illuminated by near-infrared ultrashort laser pulses. Flattened tips produced this way exhibit a plateau that is parallel to the substrate when the cantilever is mounted. They represent a valid and cost-effective alternative to commercially available plateau tips.

Effect of composite shade, increment thickness and curing light on temperature rise during photocuring.

OBJECTIVES: To examine the effect of composite shade, increment thickness and curing light characteristics on the temperature rise associated with composite photocuring. METHODS: Four shades (C2, A4, B1 and B3), four sample thicknesses (2, 3, 4 and 5 mm) of a hybrid resin composite and two curing units, one with two modes of curing, were investigated. The composite samples were packed in polytetrafluoroethylene (PTFE) moulds and cured for 40 s. Samples cured with the ramp curing mode were irradiated for only 20 s. Temperature rises on the undersurface of the curing resin composite were measured using an infrared scanning system. RESULTS: Shade C2 produced the highest maximum temperature of all shades (56.7 degrees C). Thinner samples produced greater temperature rises (2mm induced 60.9 degrees C, 5 mm induced 45.7 degrees C). Samples cured with Optilux 501 unit produced greater temperature rises (60.9 degrees C) than those cured with Dentsply unit (56.2 degrees C). CONCLUSIONS: There was a quantifiable amount of heat generated during visible light curing of resin composite. The amount of heat generated was influenced by shade selected, thickness of material and characteristics of the light curing unit.

Thermographic investigation of contemporary resin-containing dental materials.

OBJECTIVES: To measure the temperature rise induced during visible light curing of modern resin-containing dental materials and the effect of dentine sections in reducing this temperature rise. METHODS: A variety of newly introduced resin-containing materials were investigated, including flowable, packable and conventional hybrid composites, as well as a compomer and a resin modified glass ionomer material. The resin was packed into polytetrafluoroethylene (PTFE) moulds and cured for 40s. Temperature rises on the undersurface of the curing resin were measured using the Thermovision 900 infra-red scanning system. In the second part of the study, extracted, caries free teeth were sectioned into dentine disks of three thicknesses (0.7, 1.4 and 1.9 mm). Composite samples were overlaid by the disks and the insulating effect of dentine measured. RESULTS: The maximum temperature increases were: 43.1 degrees C (flowable composite), 32.8 degrees C (conventional composite), 32.8 degrees C (RMGI), 23.3 degrees C (compomer) and 22.4 degrees C (packable composite). CONCLUSIONS: There was a quantifiable amount of heat generated in resin-containing material during light curing. Dentine sections were good thermal insulators that significantly reduced temperature rises associated with resin composite photocuring.

Patient recognition of recrudescent herpes labialis: a clinical and virological assessment.

OBJECTIVES: The purpose of this study was to ascertain how accurate the general public was at diagnosing the condition of recrudescent herpes labialis. METHODS: An advertisement was placed in a local newspaper inviting patients to attend the Oral Medicine Clinic as soon as they thought they developed the clinically evident stage of herpes labialis. At the clinic, patients were examined to confirm the clinical presence of herpes labialis and also had a swab of the lesion(s) taken for virus culture. Virus culture was by the HEP-2 culture technique capable of detecting both herpes simplex Type 1 and herpes simplex Type 2. Patients also completed a detailed questionnaire concerning their knowledge of herpes labialis. RESULTS: In total, 41 patients attended for screening. The findings were that all patients had clinical herpes labialis, and herpes simplex virus was isolated in 96% of cases. In contrast, in only about 50% of cases were patients aware that their herpes labialis was caused by a virus. CONCLUSIONS: The general public are very good at recognizing herpes labialis lesions but need to be given more information about their infectivity.

Thermographic measurement of temperature change during resin composite polymerization in vivo.

OBJECTIVES: To use the technique of infrared thermography for non-invasive monitoring of temperature changes during polymerization of resin composite by measuring the infra-red emission from the surfaces of resin composite restorations during photocuring. METHODS: In this study 10 patient volunteers had resin composite restorations placed in upper incisor teeth and during photocuring the temperature rise within the composite was measured using the Thermovision 900 infra-red scanning system. RESULTS: The results demonstrate that the exotherm is almost instantaneous, occurring as soon as the light source is activated and rising to a peak at approximately 30 s before levelling off. The measurements suggest that a maximum temperature increase of 12 degrees C could occur, although this may only be for a short period (< 15 s). CONCLUSION: The range of temperature rise measured in this study (mean 5.4 degree C +/- 2.5 degree C) would suggest that the pulp may be endangered by the temperature rise which occurs during resin composite polymerization in vivo.

Thermographic assessment of dentine pin placement.

OBJECTIVE: This in-vitro study aimed to examine the change in surface temperature induced by the actions of drills for the placement of dentine pins. METHODS: Ten decoronated extracted premolar teeth were embedded by the apical tip of their roots in orthoresin. They were held in a bench vice and allowed to reach the ambient temperature of 24 degrees C. A thermal imaging camera, Agema Thermovision 900 series, was positioned 0.05 m perpendicular to the decoronated surface. Sequential recording of a series of images was stored at a rate of three per second during each stage of the pin placement procedure. This included a pilot drill, a channel cutting drill and the pin placement. All pins were 0.675 mm diameter x 2 mm in length and were placed 1 mm from the amelo-dentinal junction using a Kavo handpiece rotating at 4000 rpm. RESULTS: The mean baseline temperature for the thermally stabilized teeth was 23.9 degrees C. The action of the round pilot drill changed the temperature from baseline by 25 degrees C. The action of the channel drill generated the greatest heat, with a mean maximum temperature recorded during these procedures of 94 degrees C +/- 9 degrees C. The pilot drill produced a mean change from baseline of 31.3 degrees C +/- 17.7 degrees C during pin placement. CONCLUSIONS: The placement of dentine pins produced a high temperature increase on the surface of the dentine. All stages of pin placement gave rise to an increased temperature, but this was maximal with the channel drill. Further studies are required to determine whether these surfaces temperatures are transferred to the pulpal chamber.

Temperature changes in bovine mandibular bone during implant site preparation: an assessment using infra-red thermography.

OBJECTIVES: Changes in bone temperature during the sequence of drilling for implant site preparation using the Branemark technique were monitored using infra-red thermography. METHODS: Bovine mandibles were used to provide cortical bone of a similar quality to human mandibular bone. To ensure the consistency in the drilling procedure, one operator used a conventional dental handpiece with a motor provided by Nobelpharma. The manufacturer's specifications were followed during the implant site preparation, except that no irrigation was employed since infra-red radiation does not transmit through water. Thermal images were recorded using the Thermovision 900 system. A sequence of images was recorded during implant site preparation. Three drills were examined in terms of temperature changes during drilling over the entire area involved. The three drills used were a round bur, which determines the site of the fixture, a spiral drill (2 mm twist drill) which establishes the direction of the implant and finally a pilot drill (3 mm) which progressively increases the diameter of the site. RESULTS: Average values (n = 10 drill sequences) for maximum recorded temperature (Max T degrees C), change in temperature (delta T degrees C) from baseline and the area of involvement (mm2) for each drill in the 10 drill sequences were as follows: round, spiral (2 mm) and pilot (3 mm) drills gave maximum temperatures of 82.7 degrees C, 130.1 degrees C and 126.3 degrees C, respectively. The changes in temperature, delta T degrees C, were 45.7 degrees C, 79.0 degrees C and 78.9 degrees C for the round, 2 mm twist and 3 mm pilot drill, respectively. The average areas recorded for the round, spiral and pilot drills were 49 mm2, 140.1 mm2 and 273.0 mm2, respectively. CONCLUSIONS: It is concluded that the methodology employed accurately recorded temperature changes at and around the dental implant site, and provided preliminary baseline data against which the cooling efficacy of different irrigant systems may be compared.

[Angioimmunoblastic lymphadenopathy with dysproteinemia: personal experience with 3 cases and review of the literature]. / Linfoadenopatia angioimmunoblastica con disprotidemia: esperienza personale su tre casi e revisione della letteratura.

OBJECTIVE: We report personal experience on 3 cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD). We stress the prognostic and therapeutic aspects of this rare disease, that remain still unclear in recent literature. DESIGN: We performed a retrospective study on 3 cases of AILD, with a mean follow-up of 32.6 months (range 30-36). SETTING: Internal Medicine Unit. PATIENTS: We observed three patients, 2 males and 1 female, with a mean age of 65 years (range 51-72), with AILD confirmed by histopathological exams and evidence of unfavorable prognostic features at the time of diagnosis. INTERVENTIONS: 2 patients received polychemotherapy with cyclophosphamide+prednisone; cyclophosphamide + vincristine + prednisone. One patient was treated with low doses of prednisone (25 mg/day). MEASUREMENTS: We evaluated the degree of response (absent, partial, complete) an the time of survival (< 18 months or > 24 months). RESULTS: Response to therapy was partial in all patients; 1 patient underwent a severe bone marrow depression. All patients were alive for more than 24 months. CONCLUSIONS: The clinical course was independent of therapy (intensive or symptomatic) and prognostic criteria in all 3 patients. At present AILD is considered as a potentially malignant disease. Polychemotherapy must be used as a first choice treatment.

Electronic infrared thermography as a dental research technique.

Electronic infrared thermography is an imaging modality for the accurate quantification of surface temperature. It has been used in medicine since the 1960s but its use in dentistry has been limited. Its use in dentistry could, however, be very useful, for example in objectively quantifying post-surgical inflammation and studying the effects of treatment with agents such as analgesics and anti-inflammatory drugs.

Role of thermography in the assessment of infraorbital nerve injury after malar fractures.

We studied 45 patients with malar fractures who had some degree of infraorbital nerve deficit. Thermographic facial images failed to show any substantial changes in the temperature profiles of the affected and the normal control sides in relation to reco very of their facial sensation. Although some patients who had thermography on the day of injury showed significant temperature differences between the affected and the normal sides, these differences were probably the result of the acute inflammatory ch anges caused by the injury. We suggest that infrared thermography has little place in the assessment of infraorbital nerve deficits.

Cross resonant optical antenna.

We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.

The feasibility of using infrared thermography to evaluate minor salivary gland function in euhydrated, dehydrated and rehydrated subjects.

BACKGROUND: Infrared thermography technique (IRT) is utilized by a growing number of disciplines within medicine and dentistry. However, IRT has not been employed in the evaluation of salivary gland dysfunction. The purpose of this study was to examine the feasibility of using thermographic imaging in the evaluation of minor labial salivary gland function in subjects during euhydration, dehydration, and rehydration states. METHODS: Ten subjects were studied. Upper labial minor salivary gland secretion was quantified whilst simultaneously visualizing lower minor salivary gland output thermographically during each state. RESULTS: A significant difference was observed in the minor labial salivary flow among euhydrated, dehydrated and rehydrated, states. Despite the lack of statistical difference in the thermographic findings, IRT images reflected noticeable differences among the three hydration states. CONCLUSION: The overall results of this study suggest that IRT could potentially provide a valuable non-invasive tool for evaluating the relationship between minor labial salivary gland function and hydration status.

The efficacy of amlexanox OraDisc on the prevention of recurrent minor aphthous ulceration.

BACKGROUND: The study was designed to determine the efficacy of OraDisc (active component 2 mg amlexanox) on the prevention of aphthous ulcers treated at the prodromal stage. METHODS: Thermographic imaging was used to confirm the presence of a prodromal ulcer. Fifty-two patients were randomized to receive OraDisc (N = 26) or vehicle patches (N = 26). Patches were applied four times a day for 72 h over the prodromal area. The percentage of subjects who developed an ulcer at 72 h was compared between groups using the Fisher's exact test. RESULTS: About 50% of subjects in the OraDisc group developed an ulcer by day 4 compared with 69% in the vehicle group. Erythema score, ulcer size, pain scores and thermographically active area and temperature all showed trends towards healing in the OraDisc group. CONCLUSION: The OraDisc prevents ulcers from developing when compared with the vehicle patch.

Interface coupling transition in a thin epitaxial antiferromagnetic film interacting with a ferromagnetic substrate.

We report experimental evidence for a transition in the interface coupling between an antiferromagnetic film and a ferromagnetic substrate. The transition is observed in a thin epitaxial NiO film grown on top of Fe(001) as the film thickness is increased. Photoemission electron microscopy excited with linearly polarized x rays shows that the NiO film is antiferromagnetic at room temperature with in-plane uniaxial magnetic anisotropy. The anisotropy axis is perpendicular to the Fe substrate magnetization when the NiO thickness is less than about 15 A, but rapidly becomes parallel to the Fe magnetization for a NiO coverage higher than 25 A.

Electronic infrared thermography as a method of assessing herpes labialis infection.

The purpose of this study was to ascertain the applicability of infrared thermography to study the natural history of herpes labialis lesions. Since thermography is capable of detecting changes not visible to the naked eye, then it may be of value in complementing clinical examination of the various stages of herpes labialis. In addition, thermographic imaging is quantitative and therefore allows for an accurate assessment of temperature changes accompanying the disease process, both within patients and between patients. Ten female patients suffering from herpes labialis were studies (mean age 25 +/- 5 years). In all cases herpes simplex virus Type 1 was isolated by the HEP-2 technique. No treatment was instituted and patients were clinically assessed and thermographically imaged daily from the prodromal phase through to resolution. A marked temperature increase (1 degree C minimum) was observed within hours of the prodromal phase and maintained until day 4. As the lesions progressed to vesicle formation, the central area of the vesicle was noted to be cooler due to the insulating effect of the fluid. Even by day 6 a significant 0.5 degree C temperature increase over background was present at the involved site and this returned to normal within 8 to 10 days. The area of thermographic involvement was three to four times larger than the clinical area of involvement (60-100 mm2 versus 20-25 mm2). To assess reproducibility, we also studied patients through two additional untreated herpes labialis episodes. The prodromal phase was reproducible thermographically and characterized by a temperature increase of 1.42 degrees C +/- 0.2 degrees C. Thermographic imaging may represent a new approach to quantifying disease activity in herpes labialis, particularly in the subclinical prodromal stage.