In-line balanced detection stimulated Raman scattering microscopy

We introduce a novel configuration for stimulated Raman scattering (SRS) microscopy, called In-line Balanced Detection (IBD), which employs a birefringent plate to generate a time-delayed polarization-multiplexed collinear replica of the probe, acting as a reference. Probe and reference cross the sample at the same position, thus maintaining their balance during image acquisition. IBD can be implemented in any conventional SRS setup, by adding a few simple elements, bringing its sensitivity close to the shot-noise limit even with a noisy laser. We tested IBD with a fiber-format laser system and observed signal-to-noise ratio improvement by up to 30 dB

Coherent Raman spectroscopy with a fiber-format femtosecond oscillator

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Broadband stimulated Raman scattering with Fourier-transform detection

We propose a new approach to broadband Stimulated Raman Scattering (SRS) spectroscopy and microscopy based on time-domain Fourier transform (FT) detection of the stimulated Raman gain (SRG) spectrum. We generate two phase-locked replicas of the Stokes pulse after the sample using a passive birefringent interferometer and measure by the FT technique both the Stokes and the SRG spectra. Our approach blends the very high sensitivity of single-channel lock-in balanced detection with the spectral coverage and resolution afforded by FT spectroscopy. We demonstrate our method by measuring the SRG spectra of different compounds and performing broadband SRS imaging on inorganic blends

Balanced-detection Raman-induced Kerr-effect spectroscopy

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Broadband Coherent Raman Scattering Microscopy

Spontaneous Raman (SR) microscopy allows label-free chemically specificimaging based on the vibrational response of molecules; however, due to thelow Raman scattering cross section, it is intrinsically slow. Coherent Ramanscattering (CRS) techniques, by coherently exciting vibrational oscillators inthe focal volume, increase signal levels by several orders of magnitude underappropriate conditions. In its single-frequency version, CRS microscopy hasreached very high imaging speeds, up to the video rate; however, it providesinformation which is not sufficient to distinguish spectrally overlappedchemical species within complex heterogeneous systems, such as cells andtissues. Broadband CRS combines the acquisition speed of CRS with theinformation content of SR, but it is technically very demanding. In this Review,the current state of the art in broadband CRS microscopy, both in the coherentanti-Stokes Raman scattering (CARS) and the stimulated Raman scattering(SRS) versions are reviewed. Different technical solutions for broadband CARSand SRS, working both in the frequency and in the time domains, arecompared and their merits and drawbacks assesse

Solvent Molding of Organic Morphologies Made of Supramolecular Chiral Polymers

12sihe self-assembly and self-organization behavior of uracil-conjugated enantiopure (R)- or (S)-1,1'-binaphthyl-2,2'-diol (BINOL) and a hydrophobic oligo(p-phenylene ethynylene) (OPE) chromophore exposing 2,6-di(acetylamino)pyridine termini are reported. Systematic spectroscopic (UVvis, CD, fluorescence, NMR, and SAXS) and microscopic studies (TEM and AFM) showed that BINOL and OPE compounds undergo triple H-bonding recognition, generating different organic nanostructures in solution. Depending on the solvophobic properties of the liquid media (toluene, CHCl3, CHCl3/CHX, and CHX/THF), spherical, rod-like, fibrous, and helical morphologies were obtained, with the latter being the only nanostructures expressing chirality at the microscopic level. SAXS analysis combined with molecular modeling simulations showed that the helical superstructures are composed of dimeric double-cable tape-like structures that, in turn, are supercoiled at the microscale. This behavior is interpreted as a consequence of an interplay among the degree of association of the H-bonded recognition, the vapor pressure of the solvent, and the solvophobic/solvophilic character of the supramolecular adducts in the different solutions under static and dynamic conditions, namely solvent evaporation conditions at room temperature.partially_openopenĐorđević, Luka; Marangoni, Tomas; Miletić, Tanja; Rubio-Magnieto, Jenifer; Mohanraj, John; Amenitsch, Heinz; Pasini, Dario; Liaros, Nikos; Couris, Stelios; Armaroli, Nicola; Surin, Mathieu; Bonifazi, DavideĐorđević, Luka; Marangoni, Tomas; Miletic, Tanja; Rubio Magnieto, Jenifer; Mohanraj, John; Amenitsch, Heinz; Pasini, Dario; Liaros, Nikos; Couris, Stelios; Armaroli, Nicola; Surin, Mathieu; Bonifazi, David

Tunable 30 fs light pulses at 1 W power level from a Yb-pumped optical parametric oscillator

We report on a Yb-pumped optical parametric oscillator (OPO) that delivers 30 fs pulses with spectral coverage from 680 to 910 nm and an average output power of up to 1.1 W. The resulting peak power is â\u88¼0.5 MW, which is, to the best of our knowledge, the highest ever demonstrated in a femtosecond OPO. The intensity noise remains at a level of 0.2% rms, and rapid wavelength tuning is obtained by simply scanning the resonator length. The performances of the OPO are promising for a variety of applications in nonlinear microscopy and ultrafast spectroscopy

Bilateral Symmetry of Visual Function Loss in Cone-Rod Dystrophies.

PURPOSE: To investigate bilateral symmetry of visual impairment in cone-rod dystrophy (CRD) patients and understand the feasibility of clinical trial designs treating one eye and using the untreated eye as an internal control. METHODS: This was a retrospective study of visual function loss measures in 436 CRD patients followed at the Ophthalmology Department of the Catholic University in Rome. Clinical measures considered were best-corrected visual acuity, focal macular cone electroretinogram (fERG), and Ganzfeld cone-mediated and rod-mediated electroretinograms. Interocular agreement in each of these clinical indexes was assessed by t- and Wilcoxon tests for paired samples, structural (Deming) regression analysis, and intraclass correlation. Baseline and follow-up measures were analyzed. A separate analysis was performed on the subset of 61 CRD patients carrying likely disease-causing mutations in the ABCA4 gene. RESULTS: Statistical tests show a very high degree of bilateral symmetry in the extent and progression of visual impairment in the fellow eyes of CRD patients. CONCLUSIONS: These data contribute to a better understanding of CRDs and support the feasibility of clinical trial designs involving unilateral eye treatment with the use of fellow eye as internal control

LDL-cholesterol control in the primary prevention of cardiovascular diseases. An expert opinion for clinicians and health professionals

Aims: Although adequate clinical management of patients with hypercholesterolemia without a history of known cardiovascular disease is essential for prevention, these subjects are often disregarded. Furthermore, the scientific literature on primary cardiovascular prevention is not as rich as that on secondary prevention; finally, physicians often lack adequate tools for the effective management of subjects in primary prevention and have to face some unsolved relevant issues. This document aims to discuss and review the evidence available on this topic and provide practical guidance. Data synthesis: Available algorithms and risk charts represent the main tool for the assessment of cardiovascular risk in patients in primary prevention. The accuracy of such an estimate can be substantially improved considering the potential contribution of some additional risk factors (C-reactive protein, lipoprotein(a), family history of cardiovascular disease) and conditions (environmental pollution, sleep quality, socioeconomic status, educational level) whose impact on the cardiovascular risk has been better understood in recent years. The availability of non-invasive procedures to evaluate subclinical atherosclerosis may help to identify subjects needing an earlier intervention. Unveiling the presence of these conditions will improve cardiovascular risk estimation, granting a more appropriate intervention. Conclusions: The accurate assessment of cardiovascular risk in subjects in primary prevention with the use of algorithms and risk charts together with the evaluation of additional factors will allow physicians to approach each patient with personalized strategies, which should translate into an increased adherence to therapy and, as a consequence, a reduced cardiovascular risk