Search

We present a novel optical sensor that is able to measure the real dimensions and areas of anatomical objects in endoscopic images by taking advantage of the knowledge of the real distance from the endoscope tip to the anatomical wall under examination. At present the major obstacle to quantitative endoscopy is the inability of calibrating the acquired images because of the magnification system. In order to solve this problem in a satisfactory way we have studied and realized a new system combining an imaging system, applied to a clinical endoscope, with an absolute distance sensor based on fiber optic low coherence interferometry (FOLCI). Up to now the sensor has been tested on pig trachea, simulating the real humidity and temperature (37 °C) conditions. The sensor show high sensitivity, providing correct measurements of the size of biological samples even in the case of very low reflected power (down to 2-3 nW). [ABSTRACT FROM AUTHOR]

We present a fast and simple method to determine the sign of the nonlinear coefficient n2 in films with high nonlinearity. The method exploits the effect of spatial self-phase modulation and the role of wavefront curvature that leads to a specific far field pattern that is dependent on the sign of n2 and on the sample position. The method can be considered a 'visualization' of the Z-scan for highly nonlinear films. Application to nematic liquid crystals under different experimental conditions confirms the results expected from the theory. [ABSTRACT FROM AUTHOR]

We report the results of an extended investigation performed on composite polymeric materials with the aim of obtaining compounds suitable for holographic recording. In order to investigate the material properties a characterization of holographic reflection gratings at different writing wavelength (514.5, 457 and 405 nm) has been performed. The volume grating presents high diffraction efficiency (>60%), high sensitivity (>103 cm J[?]1) and refractive index modulation Dn[?]0.01 even for writing wavelength in the blue range. We show that following a strategy of two basic components leading to phase separation during the photopolymerization process, most of the requirements for holographic data storage are achieved. The one that needs further improvement concerns long term mechanical stability. [ABSTRACT FROM AUTHOR]

Introduction: This study proposes a revised version of the Reflux Symptom Index (R-RSI), a seventeen-item questionnaire that was revised to increase the suspicion of laryngopharyngeal reflux disease (LPRD)., Methods: Internal validation involved 213 participants, comprising 160 subjects without a previous LPRD diagnosis and 53 subjects with a self-reported previous diagnosis of LPRD with or without gastroesophageal reflux disease (GERD). Test-retest reliability and internal consistency were calculated. For the external validation, 56 patients (independent from the previous cohort) were enrolled to explore the R-RSI screening properties and determine a cutoff using 24-h MII-pH as the gold standard., Results: R-RSI test-retest reliability was high, both for the total score (ICC: 0.970) and for each item (ranging from 0.876 to 0.980). Cronbach's alpha was 0.910, indicating excellent internal consistency of the questionnaire. Participants with a previous self-reported diagnosis scored significantly higher (mean 24.94 ± 7.4; median 26, IQR 20-29) than those without a previous diagnosis (mean 4.66 ± 5.3; median 4, IQR 1-6) (p value <0.0001). Participants with both previous LPRD and GERD diagnoses had higher scores (27.20 ± 7.8) compared to those with only LPRD (21.77 ± 5.5) (p value = 0.003). Using 24-h MII-pH diagnosis as a gold standard, the optimal R-RSI cutoff point was determined to be 18, with a sensitivity of 84.5% and a specificity of 81.8%, positive predictive value of 95%, and negative predictive value of 60%., Conclusions: Our results suggest that the R-RSI may be useful to suspect LPRD, with or without GERD. The R-RSI is a self-administered patient-reported outcome questionnaire that demonstrates excellent reliability and high screening properties. Employing a cutoff of ≥18 in the R-RSI can assist in diagnosing and monitoring LPRD., (© 2024 S. Karger AG, Basel.)

Background: The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a significant threat to crop production. Alternatives to synthetic pesticides are needed for its management. Here we investigated the effect of sulphur on H. halys. Experiments were performed to evaluate both mortality and deterrence/repellence of H. halys following sulphur treatments in laboratory and semi-field conditions., Results: Brown marmorated stink bug mortality was not influenced by sulphur applications. However, in two-choice experiments in insect cages and olfactometer, more H. halys adults moved toward the untreated control rather than the sulphur-treated food sources, with a high effect as the concentration increased. A semi-field experiment using potted apple plants confirmed the results observed in the laboratory, showing a deterrent and/or repellent effect of sulphur-based products on H. halys., Conclusions: Sulphur applications were associated with a deterrent/repellent effect on the brown marmorated stink bug. The use of sulphur-based products could represent a promising tool for Integrated Pest Management strategies against H. halys in fruit crops. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Introduction: The increasing population of survivors of head and neck carcinomas is becoming more conspicuous. Consequently, the pivotal role of quality of life, particularly elucidated through the assessment of dysphagia and dysphonia, is progressively influencing the decision-making process. The current study aims to assess whether VITOM 3D could offer a comparable post-treatment quality of life to traditional approaches for patients with laryngeal cancer and oro-hypopharyngeal cancer., Methods: A case series of laryngeal cancer and oro-hypopharyngeal cancer patients treated either with an exoscopic-assisted surgical setup and with conventional treatments (transoral microsurgery and radio-chemotherapy) at the Otolaryngology Unit of IRCCS San Martino Hospital, Genoa, is presented. The post-treatment quality of life of the two cohorts were compared through the administration of the University of Washington Quality of Life Questionnaire, Voiceik Handicap Index-10, M.D. Anderson Dysphagia Inventory were administrated to both cohorts of patients., Results: In the laryngeal cancer group, a total of 79 patients were included. Of these, 50.1% underwent transoral exoscope-assisted surgery, while 49.9% underwent primary transoral microscopic-assisted surgical approach. No significant differences were observed in terms of the University of Washington Quality of Life Questionnaire and Voice Handicap Index-10 between the two subgroups. Conversely, in the oro-hypopharyngeal cancer group, 43 patients were included. Of these, 37.2% underwent primary transoral exoscope-assisted surgery, while 62.8% received (chemo)radiotherapy. No notable differences were reported in terms of the University of Washington Quality of Life Questionnaire and M.D. Anderson Dysphagia Inventory between the transoral exoscope-assisted surgery and (chemo)radiotherapy subgroups., Conclusions: Assessments of quality of life, conducted through the University of Washington Quality of Life Questionnaire questionnaire, dysphonia evaluations using the Voice Handicap Index-10, and dysphagia assessments employing the M.D. Anderson Dysphagia Inventory questionnaire, demonstrate analogous outcomes between conventional treatment modalities and transoral interventions utilizing the 3D exoscope., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2024 Marchi, Bellini, Ioppi, Simoni, Iandelli, Filauro, Mora, Sampieri and Peretti.)

Statistical analysis of the properties of single microparticles, such as cells, bacteria or plastic slivers, has attracted increasing interest in recent years. In this regard, field flow cytometry is considered the gold standard technique, but commercially available instruments are bulky, expensive, and not suitable for use in point-of-care (PoC) testing. Microfluidic flow cytometers, on the other hand, are small, cheap and can be used for on-site analyses. However, in order to detect small particles, they require complex geometries and the aid of external optical components. To overcome these limitations, here, we present an opto-fluidic flow cytometer with an integrated 3D in-plane spherical mirror for enhanced optical signal collection. As a result, the signal-to-noise ratio is increased by a factor of six, enabling the detection of particle sizes down to 1.5 µm. The proposed optofluidic detection scheme enables the simultaneous collection of particle fluorescence and scattering using a single optical fiber, which is crucial to easily distinguishing particle populations with different optical properties. The devices have been fully characterized using fluorescent polystyrene beads of different sizes. As a proof of concept for potential real-world applications, signals from fluorescent HEK cells and Escherichia coli bacteria were analyzed.

Objective: Dysphagia is a common symptom in Parkinson's disease (PD) and it represents a negative prognostic factor because of its complications. This study is to evaluate pharyngeal dysphagia for boluses of various consistencies with Fiberoptic Endoscopic Evaluation of Swallowing (FEES) and Pharyngeal High-Resolution Manometry (PHRM) in a group of PD patients, making a comparison between the information provided by the two exams., Methods: Group of 20 patients affected by PD was selected and initially subjected to a qualitative evaluation of the swallowing performing FEES. Subsequently, they were evaluated by PHRM to identify quantitative measures associated with pressures expressed by pharyngeal organs during swallowing. Values obtained in the study group were compared with those recorded in a group of 20 healthy subjects., Results: Study showed that Pmax (the maximum pressure elicited by the single pharyngeal muscle structures involved in swallowing) was significantly lower than the control group (p<0.05) for all the boluses and consistency tested, in particular for the Tongue base and the Cricopharyngeal muscle. Pmean pre-swallowing pressure (represents the mean value of a contraction in which basal and maximal pressure where normally calculated) was significantly higher compared to normal subjects for the Tongue base and the Cricopharyngeal muscle (p<0.05). Mean intra-swallowing pressure was higher for the Velopharynx and the Cricopharyngeal muscle, but lower for the tongue base. Pmax and Pmean at PHRM were altered independently to the degree of dysphagia detected at FEES, and they did not correlate either with the location of the residue or with the type of bolus. Images displayed at the FEES, found the corresponding biomechanical explanations in the PHRM, which also allowed us to quantify the extent of the dysfunction, through the calculation of the pressures generated in the various structures studied., Conclusion: PHRM is particularly useful in the early detection of dysphagia, when FEES may still show no evidence of abnormal swallowing., Competing Interests: Declaration of Competing Intrest All authors declare that they have no conflicts of interest, (Copyright © 2022. Published by Elsevier B.V.)

We show here that light polarization of a beam propagating through a heliconical cholesteric cell can be controlled by tuning the Bragg resonance of the structure. We demonstrate that this control is achieved by varying either the low-frequency electric field or the intensity of a pump beam impinging on the sample. The study confirms the recently reported phenomenon of optical tuning of the heliconical cholesterics and opens the door for the development of simple and efficient polarization modulators controlled electrically or optically.

Objective: To correlate, RSI with SVHI, in a group of singing students, by means of a specific anamnestic questionnaire which analyzes the physical, social, emotional, and economic impacts of voice problems on their lives. This study is a cross-sectional single-center observational study., Methods: Forty-two modern singing students (26F/16M; average age: 24.9 ± 5.7; range: 16-46 years old) were recruited. A self-assessment of the singing-voice (SVHI) and of reflux symptom (RSI) was performed., Results: Using the validated RSI threshold, 31% of participants were classified as RSI greater than 13 as an indication of suspected LPR. Classifying the SVHI score as proposed in the recent literature (cutoff of 20.35) our sample was a voice disorders prevalence of 71.4%. There was no significant positive or negative relationship between RSI and SVHI total score (rho = 0.238, P = 0.13). Instead, by considering the relationship between the individual items of the two questionnaires, it is highlighted that the item 1 of SVHI was significantly correlated with most of the RSI items (P = 0.0001-0.006). In the same vein, the item 5 of SVHI was correlated to hoarseness and coughing (P = 0.005-0.006). The item 20 of SVHI was significantly correlated with hoarseness, excess mucus in the throat or postnasal drip and with the pharyngeal Globus sensation (P = 0.001-0.005). By aggregating the SVHI item response as a positive response (2-4) versus a negative response (0 or 1) between "RSI pathology classification," a significant association was observed for SVHI item 1 (P < 0.021), item 5 (P < 0.006), item 20 (P < 0.042), item 24 (P < 0.044) item 25 (P < 0.047). These associations were confirmed by univariate binary logistic. Multivariate binary logistic regression confirms that SVHI Item 1, Item 5 were more associated with RSI positive. Based on results, we propose a questionnaire that combines the most relevant SVHI items correlated to LPRD (SVHI-10-LPRD questionnaire). Cronbach's alpha coefficient for the 10 items selected was 0.87; item-total correlation coefficients for each item were in the range of 0.461 to 0.670., Conclusions: This pilot study shows that, in case of significant RSI for LPR, it is possible to observe a significant association with some symptoms described in SVHI. These results underline that the association of the RSI and SVHI questionnaires administered to singers and singing students, can represent a simple screening to reveal possible alterations of the singing voice correlate to LPR. Moreover, we propose a Singing Voice Handicap Index correlated to LPR (SVHI-10-LPRD). It will be necessary to increase the sample of subjects in the study to confirm these preliminary data., (Copyright © 2020 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate retrospectively the incidence of complications during fiberoptic endoscopic evaluation of swallowing (FEES) in 5,680 examinations., Patients and Methods: 5,680 patients were evaluated at the Department of Otorhinolaryngology, Audiology and Phoniatrics of Pisa University Hospital between January 2014 and December 2018, involving both inpatients and outpatients. Most common comorbidities included neurological pathologies such as stroke (11.8%), neurodegenerative diseases (28.9%) and a history of previous head and neck surgery (24.6%). The evaluation was conducted by clinicians with experience in swallowing for a minimum of 10 years with the assistance of one or more speech-language pathologists., Results: In all patients studied the endoscope insertion was tolerated, and it was possible to visualize the pharyngolaryngeal structures. Three subjects refused to undergo the procedure after being informed regarding the protocol and were therefore not included in this study. Most patients reported discomfort (70.1%) and gagging (20.8%). In a minority of patients complications were recorded, such as anterior epistaxis (0.1%), posterior epistaxis (0.02%), vasovagal crises (0.08%) and laryngospasm (0.04%). Especially laryngospasm was recorded in patients affected by amyotrophic lateral sclerosis. Multivariate binary logistic regression showed that discomfort (OR 9.944; CI 7.643-12.937), chronic gastrointestinal diseases (OR 2.003; CI 1.518-2.644), neurodegenerative diseases (OR 1.550; CI 1.302-1.846) and brain tumors (OR 1.577; CI 1.179-2.111) were risk factors associated with minor complications., Conclusions: FEES proved to be easy to perform, well tolerated by the patients and cost-effective. It can be performed at the patient's bedside, and it is characterized by a low rate of complications. As a matter of fact, normally only discomfort, gagging and/or vomiting are reported. Complications occurred only rarely, such as anterior or posterior epistaxis episodes or vasovagal crises, but these are still easily managed. Exceptionally, more severe complications are reported: adverse drug reactions to substances such as blue dye (methylene blue) and local anesthetics (not used in our protocol), and laryngospasm., (© 2022 S. Karger AG, Basel.)

The efficiency of photomobile polymers (PMP) in the conversion of light into mechanical work plays a fundamental role in achieving cutting-edge innovation in the development of novel applications ranging from energy harvesting to sensor approaches. Because of their photochromic properties, azobenzene monomers have been shown to be an efficient material for the preparation of PMPs with appropriate photoresponsivity. Upon integration of the azobenzene molecules as moieties into a polymer, they act as an engine, allowing fast movements of up to 50 Hz. In this work we show a promising approach for integrating ZnO nanoparticles into a liquid crystalline polymer network. The addition of such nanoparticles allows the trapping of incoming light, which acts as diffusive points in the polymer matrix. We characterized the achieved nanocomposite material in terms of thermomechanical and optical properties and finally demonstrated that the doped PMP was better performing that the undoped PMP film.

We show here that the light-induced tuning of the Bragg reflection recently demonstrated in heliconical cholesterics opens new perspectives to nonlinear optical propagation in liquid crystals. We highlight that, by properly adjusting the static electric field that stabilizes the heliconical structure, a dramatic change of the refractive index of the circularly polarized resonant mode can be achieved. Additionally, a stop band for a definite range of light intensity is obtained that can be tuned in order to get the conditions of self-induced transparency.

Near-infrared light is commonly used to move small objects floating on water by exploiting the Bénard-Marangoni convection. This is because infrared light is absorbed well by water and the induced thermal gradients are responsible for the objects' motion. However, visible light was recently used to move macroscopic objects on the free liquid surfaces. In this work, we show the use of visible light to rotate symmetric millimeter-sized objects. Those objects represent light-driven macro motors that are able to work in a continuous or step-by-step mode. We studied light intensity's effects on our system's angular velocity and estimated the entire process's conversion efficiency.

We demonstrate the all optical control of the molecular orientation of nematic liquid crystals confined in microfluidic channels engraved in lithium niobate. Microchannels are obtained by a novel approach based on femtosecond pulse laser micromachining carried on in controlled atmosphere. The combined effect of photovoltaic and pyroelectric fields generated by light in lithium niobate crystals on the liquid crystal orientation, is reported for the first time. The total space charge field and its dependence on the incident light intensity can be controlled by changing the direction of pump light propagation through the microfluidic chip. The results reported in this manuscript demonstrate that liquid crystals and lithium niobate can efficiently be combined in microfluidic configuration, in order to push forward a novel class of optofluidic devices.

We report the experimental evidence of nonlinear optical response in DNA lyotropic nematic liquid crystals. Pump-probe experiments indicate that the non-linearity is remarkably large. Quantitative assessment of the non-linear optical coefficient by transient optical grating demonstrates that the response is of the same order of the well-known Giant Optical Nonlinearity (GON) of thermotropic nematics. These results represent a further incentive to the current investigation of potential applications of DNA in biophotonics.

Photomobile polymer (Pmp) films are fabricated by using a cheap and fast process. The working mechanism of the Pmp-film motion under illumination is explained. Details concerning the film structure and formation are given. Two related applications regarding light-induced caterpillar-miming motion and photocontrolled electrical switches are proposed., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the realization and characterization of an optofluidic microlaser based on a Fabry-Perot resonator fabricated by exploiting two direct writing fabrication techniques: the femtosecond laser micromachining and the inkjet printing technology. In this way a standard Fabry-Perot cavity has been integrated into an optofluidic chip. When using rhodamine 6G dissolved in ethanol at concentration of 5∙10 -3 mol/l, laser emission was detected at a threshold energy density of 1.8 μJ/mm 2 at least one order of magnitude lower than state-of-the-art optofluidic lasers. Linewidth below ~0.6 nm was measured under these conditions with a quality factor Q~10 3 . These performances and robustness of the device makes it an excellent candidate for biosensing, security and environment monitoring applications.

Competing Interests: All authors declare that they have no conflict of interest. Human and animal studies This article does not contain any studies with human participants or animals performed by any of the authors. Informed consent This article does not include any personal data needing informed consent. Funding The study had no funding.

We report on the observation of a modulated pattern induced by a single laser beam in a polymeric film. In spite of the simple geometrical configuration, the analysis of the far field diffraction pattern allows a sensitive retrieving of the wavelength of the recording beam and of its incidence angle, pointing out the high information content of the recorded spot. A theoretical model is presented which satisfactorily explains the observed behavior. It takes into account the interaction of structured light with structured matter with the same symmetries and spatial modulation frequencies close to each other. This result shows a feature of the interaction between structured light and structured matter which has not been explored yet.

We report the light-induced control of optical phase shift by a liquid crystal cell made with LiNbO3:Fe crystals as substrates. We show that a phase shift of a few πs can be easily reached for two orthogonal polarizations due to liquid crystal reorientation driven by the photovoltaic electric field originated in the substrates. This effect is exploited to get all-optical switching with a contrast of about 80%, by 2 s pump pulse.

Nonlinear optical response of the cybotactic nematic phase of a bent-core mesogen has been investigated for the first time through self-phase modulation induced by a Gaussian beam. The material exhibits a high nonlinear response achieving a nonlinear index n(2)≈5×10(-5)  cm(2)/W and an unconventional behavior characterized by two different regimes. While the high-intensity regime can be easily explained in terms of a thermal indexing effect, the low-intensity regime is metastable and characterized by an unusual dependence on the irradiation energy. It is suggested that a change of the director configuration, possibly due to a light-induced modification of surface anchoring, is responsible for the observed behavior.