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We address the surface vs bulk origin of the second-order optical nonlinearity in AlGaAs nanocylinders through polarization-resolved measurements. By comparing numerical simulations accounting just for bulk second-order nonlinearity with experimental results, we show that the surface contribution to second-harmonic generation (SHG) cannot be neglected and depends on the resonant conditions of the nanocylinder. Additionally, our analysis suggests that bulk and surface SHG are competing effects, and that their interference might influence the overall efficiency.

Switching of light polarization on the sub-picosecond timescale is a crucial functionality for applications in a variety of contexts, including telecommunications, biology and chemistry. The ability to control polarization at ultrafast speed would pave the way for the development of unprecedented free-space optical links and of novel techniques for probing dynamical processes in complex systems, as chiral molecules. Such high switching speeds can only be reached with an all-optical paradigm, i.e., engineering active platforms capable of controlling light polarization via ultrashort laser pulses. Here we demonstrate giant modulation of dichroism and birefringence in an all-dielectric metasurface, achieved at low fluences of the optical control beam. This performance, which leverages the many degrees of freedom offered by all-dielectric active metasurfaces, is obtained by combining a high-quality factor nonlocal resonance with the giant third-order optical nonlinearity dictated by photogenerated hot carriers at the semiconductor band edge., (© 2024. The Author(s).)

All-optical modulation yields the promise of high-speed information processing. In this field, metasurfaces are rapidly gaining traction as ultrathin multifunctional platforms for light management. Among the featured functionalities, they enable light-wavefront manipulation and more recently demonstrated the ability to perform light-by-light manipulation through nonlinear optical processes. Here, by employing a nonlinear periodic metasurface, we demonstrate the all-optical routing of telecom photons upconverted to the visible range. This is achieved via the interference between two frequency-degenerate upconversion processes, namely, third-harmonic and sum-frequency generation, stemming from the interaction of a pump pulse with its frequency-doubled replica. By tuning the relative phase and polarization between these two pump beams, we route the upconverted signal among the diffraction orders of the metasurface with a modulation efficiency of up to 90%. This can be achieved by concurrently engineering the nonlinear emission of the individual elements (meta-atoms) of the metasurface along with its pitch. Owing to the phase control and ultrafast dynamics of the underlying nonlinear processes, free-space all-optical routing could be potentially performed at rates close to the employed optical frequencies divided by the quality factor of the optical resonances at play. Our approach adds a further twist to optical interferometry, which is a key enabling technique employed in a wide range of applications, such as homodyne detection, radar interferometry, light detection and ranging technology, gravitational-wave detection and molecular photometry. In particular, the nonlinear character of light upconversion combined with phase sensitivity is extremely appealing for enhanced imaging and biosensing., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Nanophotonics systems have recently been studied under the perspective of non-Hermitian physics. Given their potential for wavefront control, nonlinear optics and quantum optics, it is crucial to develop predictive tools to assist their design. We present here a simple model relying on the coupling to an effective bath consisting of a continuum of modes to describe systems of coupled resonators, and test it on dielectric nanocylinder chains accessible to experiments. The effective coupling constants, which depend non-trivially on the distance between resonators, are extracted from numerical simulations in the case of just two coupled elements. The model predicts successfully the dispersive and reactive nature of modes for configurations with multiple resonators, as validated by numerical solutions. It can be applied to larger systems, which are hardly solvable with finite-element approaches.

Bone is a multi-skilled tissue, protecting major organs, regulating calcium phosphate balance and producing hormones. Its development during childhood determines height and stature as well as resistance against fracture in advanced age. Estrogens are key regulators of bone turnover in both females and males. These hormones play a major role in longitudinal and width growth throughout puberty as well as in the regulation of bone turnover. In women, estrogen deficiency is one of the major causes of postmenopausal osteoporosis. In this review, we will summarize the main clinical and experimental studies reporting the effects of estrogens not only in females but also in males, during different life stages. Effects of estrogens on bone involve either Estrogen Receptor (ER)α or ERβ depending on the type of bone (femur, vertebrae, tibia, mandible), the compartment (trabecular or cortical), cell types involved (osteoclasts, osteoblasts and osteocytes) and sex. Finally, we will discuss new ongoing strategies to increase the benefit/risk ratio of the hormonal treatment of menopause.

Objectives: With 39,359 entries on PubMed, periodontal medicine has a prominent position in periodontal research. Good patient care requires well-advised physicians, and whereas the dental community is informed about the relationships between periodontal diseases (PDs) and an increasing number of systemic pathologies, we wondered whether general practitioners were too. Thus, we aimed to evaluate their knowledge of the links between periodontal and systemic diseases., Methods: To this end, we sent an electronic questionnaire to the 2350 general practitioners registered to the URPS (Union régionale des Professionnels de Santé) of Midi-Pyrénées, France. They were asked about their practice, their attitude during a medical examination, and their knowledge about PDs., Results: The analysis of 222 properly answered questionnaires showed that while most general practitioners are aware of the relationships between PDs and diabetes or cardiovascular diseases, the majority of them are unaware that obesity and respiratory and joint diseases are also concerned. Indeed, 94% of the questioned subjects consider their insight of PDs to be insufficient. Nevertheless, more than half of the interrogated physicians cared about their patients' oral health and dental care., Conclusions: Education regarding relationships between periodontal and systemic diseases must be improved among general practitioners who are in the front line to refer high-risk patients to a periodontist., (Copyright © 2017 Elsevier Inc. All rights reserved.)

This article comes within the compass of a research program (entitled CorAge. Bodily Experiences and AgePassages among 9-13 year-olds (ANR-09-ENFT-017) conducted between 2009 and 2013 about the emergence of a "new" age in life--"preadolescence"--as instanced in France (Alsace, Lorraine) and Italy (Venetia). The impressive amount of references to "early puberty" and "precocious puberty", in a context of feeling of a premature end of childhood, led us to make an in-depth study of this issue: first, through an analysis of international and French and Italian medical journals; second, through interviews with health professionals. Following the thesis of Foucault, we assume that the discourses on puberty timing participate of classifications of the child body drenched with moral representations of childhood, especially on gender and age issue. Our results: the question of whether a secular trend in puberty timing even exists continues to be debated between American and European scientists. Second, the terms "puberty", "precocious puberty", "early puberty" have been used to indicate a variety of puberty markers, increasing confusion. A controversy has focused on early breast development in girls, because this attribute is questioning the order of ages and gender. Moreover, psychosocial factors presented as accelerating early puberty, do not demonstrate the relation between earliness and risk behavior. The literature, as it is moved by the female precocity, creates a medical category to objectify the complex and flexible process of puberty and invent female child precocity. These differences between American and European scholars and the interviews with French and Italian health professional show a gap between the international literature and practitioners, clinicians and nurses who regularly work with children: they neither find pubertal advancement, nor increase of "true precocious puberty", although they share concerns about premature feminization of girls (France) or environmental toxicity (Italy) on children., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Although parathyroid cysts are rarely described in the literature, they should be considered in the differential diagnosis of cysts occurring in the anterior compartment of the neck. We report two cases. The presence of elevated parahormone in the clear fluid aspirate is the diagnostic criterion. Parathyroid cysts may be functional, probably resulting from cystic formation of a parathyroid adenoma, or non function with their own epithelial lining, probably arising from remnants of the pharyngeal pouch or Kursteiner's canal. Search for both hypercalcemia and hypophosphoremia are needed. Fine needle aspiration provides the diagnosis and is also the treatment of choice for non-functional parathyroid cysts. Aspiration of functional cysts can reduce the hormone level to normal prior to surgical removal.

Glandular tumors of the external auditory canal are rare; their etiopathogenesis is uncertain. The term ceruminoma, often used for these tumors, is imprecise. The 1978 who classification is reviewed. The authors describe their experience with 5 cases which illustrate the salient diagnostic therapeutic, and prognostic characteristics of these tumors.

The authors present their experience of the malignant, mucosal melanomas involving the nasal cavity and paranasal sinuses through a retrospective study of 7 cases, observed in Rouen from 1977 to 1988. The results are compared to a review of world literature. The mucosal melanoma of the nose and sinus is a rare entity, representing approximatively 40 per cent of all sinonasal neoplasias. The signs and symptoms of sinonasal melanomas are non-specific. Therefore, the diagnosis is often delayed. The histological diagnosis is difficult given the substantial polymorphism of these tumors and the experience of achromatous forms. Electron microscope study and immuno-histo-chemical techniques using various monoclonal antibodies make it possible to eliminate the other major, differential diagnoses. Surgery is the primary method of treatment, sometimes combined with adjunctive postoperative radiotherapy. More recently, combined treatment with interferon and cimetidine appears to be interesting. The prognosis is very poor, if compared to skin melanomas, with a five year survival rate of 5 to 30 per cent. Local recurrence at the primary site and distant metastases are the most common caused of treatment failure.