Scheme for sub-shot-noise transmission measurement using a time multiplexed single-photon source

A promising result from optical quantum metrology is the ability to achieve sub-shot-noise performance in transmission or absorption measurements. This is due to the significantly lower uncertainty in light intensity of quantum beams with respect to their classical counterparts. In this work, we simulate the outcome of an experiment that uses a multiplexed single-photon source based on pair generation by continuous spontaneous parametric down conversion (SPDC) followed by a time multiplexing set-up with a binary temporal division strategy, considering several types of experimental losses. With such source, the sub-Poissonian statistics of the output signal is the key for achieving sub-shot-noise performance. We compare the numerical results with two paradigmatic limits: the shot-noise limit (achieved using coherent sources) and the quantum limit (obtained with an ideal photon-number Fock state as the input source). We also investigate conditions in which threshold detectors can be used, and the effect of input light fluctuations on the measurement error. Results show that sub-shot-noise performance can be achieved, even without using number-resolving detectors, with improvement factors that range from 1.5 to 2. This technique would allow measurements of optical absorption of a sample with reasonable uncertainty using ultra-low light intensity and minimum disruption of biological or other fragile specimens.Comment: 10 pages, 8 figure

Surgical and postsurgical wound care in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disorder. Several medical treatments, with varying degree of efficacy, have been developed. However, in most cases of advanced (HS), the definitive treatment option is often represented by surgical excisions. Surgical techniques, reconstructive approach, and local wound care should be accurately designed in order to obtain the best result. In this letter, we analyzed the possible surgical treatments and local wound care. A literature review was performed on the various surgical treatments, reconstructive techniques, and local wound care. Surgical treatment is a common therapeutic modality for HS. Different surgical reconstructive techniques and postsurgical wound care approaches are described for the management of HS patients. There were few high-quality evidence-based studies evaluating the surgical management of HS. Many disparate HS severity scores were used in these studies making comparison between them difficult. Nonetheless, research into different surgical approaches and wound care management has increased substantially in the past decade and has given patients more surgical therapeutic strategies. The description of the best combinations and timing of surgery, wound care and medical therapies, will be a matter of future research for the definition of the optimal management of HS patient

Hidradenitis suppurativa: Surgical and postsurgical management

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory disorder. Several medical treatments, with varying degrees of efficacy, have been developed. However, in most cases of advanced HS, the definitive treatment option is often represented by surgical excisions. Objective: Surgical techniques, reconstructive approach, and local wound care should be accurately designed in order to obtain the best result. In this review we analyze the possible surgical treatments and local wound care. Methods: A MEDLINE search was performed on the various surgical treatments, reconstructive techniques, and local wound care. Results: Surgical treatment is a common therapeutic modality for HS. Different surgical reconstructive techniques and post-surgical wound care approaches are described for the management of HS patients. Conclusions: There were few high-quality evidence-based studies evaluating the surgical management of HS. Many disparate HS severity scores were used in these studies, making comparisons between them difficult. Nonetheless, research on different surgical approaches and wound care management has increased substantially in the past decade and it has given patients more surgical therapeutic strategies. The description of the best combinations and timing of surgery, wound care, and medical therapies will be a matter of future research for the definition of the optimal management of the HS patient

Interferometry with few photons

Optical phase determination is an important and established tool in diverse fields such as astronomy, biology, or quantum optics. There is increasing interest in using a lower number of total photons. However, different noise sources, such as electronic readout noise in the detector, and shot noise, hamper the phase estimation in regimes of very low illumination. Here we report a study on how the quality of phase determination is affected by these two sources of noise. To that end, we experimentally reconstruct different wavefronts by means of a point diffraction interferometer for different mean intensities of illumination, up to $15\ \mathrm{phot/px}$. Our interferometer features a Skipper-CCD sensor, which allows us to reduce the readout noise arbitrarily, thus enabling us to separate the effect of these two sources of noise. For two cases of interest: a spatial qudit encoding phase, consisting of d = 6 uniform phase regions, and a more general continuous phase, we see that reducing the readout noise leads to a clear improvement in the quality of reconstruction. This can be explained by a simple noise model that allows us to predict the expected fidelity of reconstruction and shows excellent agreement with the measurements

Histopathological determinants of autofluorescence patterns in oral carcinoma

Biological tissues (including oral mucosa) can absorb and re-emit specific light wavelengths, detectable through spectrophotometric devices. Such a phenomenon is known as \u201cautofluorescence\u201d (AF). Several devices evaluating tissue AF have been developed and commercialized in the last two decades. Among these, the VELscope\uae system has been proposed as a visual diagnostic aid for potentially malignant disorders and malignant lesions of the oral mucosa. In the present pilot study, we investigated which are the main histopathological features possibly related to variations in AF patterns in a set of 20 oral squamous cell verrucous carcinoma. Among all the histological features investigated, only the mean width of keratin was significantly different between hypofluorescent and hyperfluorescent carcinomas. The results of the present study demonstrate that AF features of oral malignant lesions are significantly associated with the width of their keratin layer

Biomimetic Electrospun Self-Assembling Peptide Scaffolds for Neural Stem Cell Transplantation in Neural Tissue Engineering

Spinal cord regeneration using stem cell transplantation is a promising strategy for regenerative therapy. Stem cells transplanted onto scaffolds that can mimic natural extracellular matrix (ECM) have the potential to significantly improve outcomes. In this study, we strived to develop a cell carrier by culturing neural stem cells (NSCs) onto electrospun 2D and 3D constructs made up of specific crosslinked functionalized self-assembling peptides (SAPs) featuring enhanced biomimetic and biomechanical properties. Morphology, architecture, and secondary structures of electrospun scaffolds in the solid-state and electrospinning solution were studied step by step. Morphological studies showed the benefit of mixed peptides and surfactants as additives to form thinner, uniform, and defect-free fibers. It has been observed that β-sheet conformation as evidence of self-assembling has been predominant throughout the process except for the electrospinning solution. In vitro NSCs seeded on electrospun SAP scaffolds in 2D and 3D conditions displayed desirable proliferation, viability, and differentiation in comparison to the gold standard. In vivo biocompatibility assay confirmed the permissibility of implanted fibrous channels by foreign body reaction. The results of this study demonstrated that fibrous 2D/3D electrospun SAP scaffolds, when shaped as micro-channels, can be suitable to support NSC transplantation for regeneration following spinal cord injury

Sentinel lymph node biopsy in microinvasive ductal carcinoma in situ

Background: Microinvasive breast cancer is an uncommon pathological entity. Owing to the rarity of this condition, its surgical axillary management and overall prognosis remain controversial. Methods: A database was analysed to identify patients with microinvasive ductal carcinoma in situ (DCIS) who had surgery for invasive breast cancer at the European Institute of Oncology, Milan, between 1998 and 2010. Women who had undergone axillary staging by sentinel lymph node biopsy were included in the study. Results: Of 257 women with microinvasive breast cancer who underwent sentinel lymph node biopsy (SLNB), 226 (87.9 per cent) had negative sentinel lymph nodes (SLNs) and 31 had metastatic SLNs. Twelve patients had isolated tumour cells (ITCs), 14 had micrometastases and five had macrometastases in sentinel nodes. Axillary lymph node dissection was performed in 16 of the 31 patients with positive SLNs. After a median follow-up of 11 years, only one regional first event was observed in the 15 patients with positive SLNs who did not undergo axillary lymph node dissection. There were no regional first events in the 16 patients with positive SLNs who had axillary dissection. Conclusion: Good disease-free and overall survival were found in women with positive SLNs and microinvasive DCIS. This study is in line with studies showing that SLNB inmicroinvasive DCIS may not be useful, and supports the evidence that less surgery can provide the same level of overall survival with better quality of life

Structural control on the directional amplification of seismic noise (Campo Imperatore, central Italy)

Abstract Seismic signals propagating across a fault may yield information on the internal structure of the fault zone. Here we have assessed the amplification of seismic noise (i.e., ambient vibrations generated by natural or anthropogenic disturbances) across the Vado di Corno Fault (Campo Imperatore, central Italy). The fault zone is considered as an exhumed analogue of the normal faults activated during the L'Aquila 2009 earthquake sequence. Detailed structural geological survey of the footwall block revealed that the fault zone is highly anisotropic and is affected by a complex network of faults and fractures with dominant WNW–ESE strike. We measured seismic noise with portable seismometers along a ∼500 m long transect perpendicular to the average fault strike. Seismic signals were processed calculating the horizontal-to-vertical spectral ratios and performing wavefield polarization analyses. We found a predominant NE–SW to NNE–SSW (i.e., ca. perpendicular to the average strike of the fault-fracture network) amplification of the horizontal component of the seismic waves. Numerical simulations of earthquake-induced ground motions ruled out the role of topography in controlling the polarization and the amplitude of the waves. Therefore, the higher seismic noise amplitude observed in the fault-perpendicular direction was related to the measured fracture network and the resulting stiffness anisotropy of the rock mass. These observations open new perspectives in using measures of ambient seismic noise, which are fast and inexpensive, to estimate the dominant orientation of fracture networks within fault zones