Small-scale Fourier transform spectrometers are rapidly revolutionizing infrared spectro-chemical analysis, enabling on-site and remote sensing applications that were hardly imaginable just few years ...ago. While most devices reported to date rely on advanced photonic integration technologies, here we demonstrate a miniaturization strategy which harnesses unforced mechanisms, such as the evaporation of a liquid droplet on a partially reflective substrate. Based on this principle, we describe a self-operating optofluidic spectrometer and the analysis method to retrieve consistent spectral information in spite of the intrinsically non-reproducible droplet formation and evaporation dynamics. We experimentally realize the device on the tip of an optical fiber and demonstrate quantitative measurements of gas absorption with a 2.6 nm resolution, in a 100 s acquisition time, over the 250 nm span allowed by our setup's components. A direct comparison with a commercial optical analyzer clearly points out that a simple evaporating droplet can be an efficient small-scale, inexpensive spectrometer, competitive with the most advanced integrated photonic devices.
By stabilizing the evaporation dynamics of a microliter fluorocarbon droplet, we demonstrate a fast-scan optofluidic Fourier transform (FT) spectrometer on the tip of an optical fiber operating in ...the 1000-2000 nm window with a resolution of 3.5 cm
(i.e., <1 nm at 1560 nm). Compared with other FT near-infrared (NIR) small-scale spectrometers reported in the literature, the fluorocarbon droplet spectrometer shows the largest wavelength span and span/resolution ratio, allowing spectral analysis of broadband or narrowband radiation to be easily performed. Our results open the way for the practical application of droplet spectrometers as advanced optofluidic NIR analyzers with small size and low cost that are capable of operating in harsh environments, even in the absence of electrical power sources.
Distal biceps tendon rupture occurs more often in middle-aged male population, involving the dominant arm. In this retrospective study, it's been described the occurrence of the most frequent adverse ...events and the clinical outcomes of patients undergoing surgical repair of distal biceps tendon rupture with the modified Morrey's double-incision approach, to determine better indications for patients with acute tendon injury.
Sixty-three patients with acute distal biceps tendon rupture treated with a modified double-incision technique between 2003 and 2015 were retrospectively evaluated at a mean 24 months of follow-up. Clinical evaluation including range of motion (ROM) and isometric strength recovery compared to the healthy contralateral side assessment, together with documentation of nerve injury, was performed. Patients were asked to answer DASH, OES and MEPS scores.
The ROM recovery showed excellent results compared to the healthy contralateral side. The reported major complications included: one case of proximal radio-ulnar synostosis, 3 cases of posterior interosseous nerve (PIN) palsy and one case of a-traumatic tendon re-rupture. Concerning minor complications, intermittent pain, ROM deficiency < 30° in flexion/extension and pronation/supination, isometric flexion strength deficiency < 30% and isometric supination strength deficiency < 60%, lateral antebrachial cutaneous nerve (LACBN) injury, were observed. The average DASH score was 8.5; the average OES was 41.5 and the MEPS was 96.3.
The Morrey modified double-incision technique finds its indication in young and active patients if performed within 2 weeks from injury. If performed by experienced surgeons, the advantages can exceed the drawbacks of possible complications.
Liquid droplets are ubiquitous in nature wherein surface tension shapes them into perfect spheres with atomic-scale smooth surfaces. Here, we use stable droplets that cohost equatorial acoustical and ...optical resonances phase matched to enable the exchange of energy and momentum between sound and light. Relying on free-space laser excitation of multiple whispering-gallery modes, we harness a triple-resonant forward Brillouin scattering to stimulate optomechanical surface waves. Nonlinear amplification of droplet vibrations in the 60-70 MHz range is realized with spectral narrowing beyond the limit of material loss, thereby activating the droplet as hypersound-laser emitter.
Purpose
Concerns exist regarding prosthetic positioning and post-operative limb alignment in unicompartmental knee arthroplasty (UKA). In this study, we hypothesized deviations of the post-op ...anatomical femoro-tibial angle (aFTA) and the tibial component alignment to be factors influencing UKA survivorship. Moreover, by a comparison between all-poly and metal back UKAs, we hypothesized that prosthetic design plays a role in implant survivorship.
Methods
One hundred ninety-five medial UKAs were performed on 176 patients by two experienced surgeons and one low-UKA user. One hundred and forty-seven UKAs were included in the study: 72 all-poly and 75 metal back. Measurements were performed on radiographs: mechanical femoro-tibial angle, Cartier angle, aFTA and tibial posterior slope (PS) on pre-op radiographs; femoral and tibial component varus/valgus, aFTA and tibial component PS on post-op radiographs.
Results
At an average follow-up of 61 months (min. 30, max. 107), 147 UKAs were evaluated: The reported survivorship rate was 93.1 %. Eleven implants underwent revision: ten all-poly and one metal back. No differences were reported between the two groups in the radiographic measurements. Significant radiographic differences were reported between revised and not revised UKAs: Revised UKAs were associated with overcorrection of the pre-op Cartier angle and under correction of pre-op aFTA. Most of revised UKAs were performed by the low-volume UKA surgeon.
Conclusions
Surgeon’s experience is essential to achieve good results in UKA: Preserving the tibial epiphyseal axis and avoiding excessive or insufficient corrections of the pre-operative limb alignment are predictor of successful replacement, while prosthetic designs, models and fixation geometry do not affect UKA outcome.
Level of evidence
IV.
Background
Adhesive capsulitis (AC) is a disease of the glenohumeral joint that is characterized by pain and both passive and active global stiffness with a slow and insidious onset. The disease can ...occur spontaneously (primary AC) or it can be secondary to other comorbidities, surgery, or trauma, such as fracture or dislocation. Multiple treatment approaches have been suggested: intra-articular steroid injection, physical therapy, manipulation under total anesthesia, and arthroscopic or open surgery. Shoulder manipulation under anesthesia is usually proposed to patients that suffer from severe AC and have already undergone several nonoperative treatments without benefit. Different techniques have been proposed. This study presents our manipulation technique and the clinical results we achieved after shoulder mobilization under brachial plexus block in patients with phase III primary AC.
Materials and methods
A retrospective cohort study was performed on a sample of 110 patients with phase III AC who were treated with this manipulation and followed up for 1 year. Patients underwent two assessments—before the procedure (T0) and 4 months after it (T1)—based on the Numerical Rating Scale, Simple Shoulder Test, and joint range of motion to assess shoulder pain, function, and joint articulation, respectively. Furthermore, the patients had to express their degree of satisfaction with the procedure and the results achieved.
Results
Positive and statistically significant results were recorded in terms of pain reduction (ΔNPRS = − 5.4;
p
< 0.01) and improved functionality (Simple Shoulder Test Δ = 5;
p
< 0.01). Passive range of motion was statistically significantly increased for each movement at T1. Large increases were observed in extrarotation range of motion (ROM): R1 (Δ = 77.5°) and R2 (Δ = 70°), whereas little improvements were observed in intrarotation ROM. Patients achieved satisfying functional and articular recovery in all cases. Complications that needed further treatment occurred in three cases: a brachial plexus injury, a glenoid flake fracture, and persistent pain and stiffness.
Conclusions
In this study, we proposed a standardized method of manipulation under brachial plexus block for patients affected by phase III adhesive capsulitis. The technique was applied among a large cohort of patients, who reported a high satisfaction rate and range-of-motion recovery after 4 months. This could represent an alternative treatment to surgery that has a shorter timeline and does not require patient hospitalization.
Level of evidence
: Level III, retrospective cohort study.
Liquid droplet whispering-gallery-mode microresonators open a new research frontier for sensing, optomechanics and photonic devices. At visible wavelengths, where most liquids are transparent, a ...major contribution to a droplet optical quality factor is expected theoretically from thermal surface distortions and capillary waves. Here, we investigate experimentally these predictions using transient cavity ring-down spectroscopy. With our scheme, the optical out-coupling and intrinsic loss are measured independently while any perturbation induced by thermal, acoustic and laser-frequency noise is avoided thanks to the ultra-short light-cavity interaction time. The measurements reveal a photon lifetime at least ten times longer than the thermal limit and indicate that capillary fluctuations activate surface scattering effects responsible for light coupling. This suggests that droplet microresonators are an ideal optical platform for ultra-sensitive spectroscopy of highly transparent liquid compounds in nano-liter volumes.
Droplets are very simple physical systems, whereby surface tension shapes liquids into ideal opto-mechanical devices. This has recently enabled low-viscosity liquid samples to serve as miniature ...acoustic resonators harnessing optical generation of bulk vibrations, capillaries, or surface waves. Uniquely, a simple room-temperature pendant droplet can be activated as a hypersound-laser emitter when illuminated by a free-space, low-power visible laser thanks to stimulated Brillouin scattering of optical and acoustic whispering-gallery modes. Here, we demonstrate continuous operation of a liquid polymer opto-mechanical resonator and characterize its quality factor and long-term frequency stability. Our results point to the feasibility of all-liquid micro-mechanical oscillators working in the 50-100 MHz range. The stimulated generation of high-quality surface waves on nanoliter droplets gives momentum to new optical schemes for characterization of material viscous-elastic properties, laboratory investigation of atmospheric phenomena, and mass sensing for direct analysis of biological fluids based on ultrasound-hypersound coherent generation and detection.
We report the theoretical description and the experimental demonstration of an optical resonator formed by inserting a Fiber Bragg Grating (FBG) in a closed fiber loop. The spectral characteristics ...of such a resonator strongly depend on the reflectivity of the FBG. In the wavelength region where the FBG reflectivity R is negligible, the system behaves like a conventional ring resonator. On the other hand, when R is not vanishing, a split-mode structure can be observed, associated to the degeneracy removal of two counterpropagating resonant modes. The magnitude of the mode splitting can be used to sense small variations of the FBG physical parameters, such as length, temperature or group index. An example of strain sensing with this setup is reported, showing that the mode splitting is sensitive to a mechanical strain applied to the FBG, while it is almost insensitive to a strain applied to any other point of the resonator. This peculiar feature allows to perform cavity-enhanced, local strain measurements with a reduced sensitivity to environmental perturbations, which represents an important improvement in the framework of the fiber-optic sensors.
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