Laser-ablative engineering of phase singularities in plasmonic metamaterial arrays for biosensing applications

International audienceBy using methods of laser-induced transfer combined with nanoparticle lithography, we design and fabricate large-area gold nanoparticle-based metamaterial arrays exhibiting extreme Heaviside-like phase jumps in reflected light due to a strong diffractive coupling of localized plasmons. When employed in sensing schemes, these phase singularities provide the sensitivity of 5 x 10(4) deg. of phase shift per refractive index unit change that is comparable with best values reported for plasmonic biosensors. The implementation of sensor platforms on the basis of such metamaterial arrays promises a drastic improvement of sensitivity and cost efficiency of plasmonic biosensing devices. (C) 2014 AIP Publishing LLC

3D plasmonic crystal metamaterials for ultra-sensitive biosensing

International audienceWe explore the excitation of plasmons in 3D plasmon crystal metamaterials and report the observation of a delocalized plasmon mode, which provides extremely high spectral sensitivity (> 2600 nm per refractive index unit (RIU) change), outperforming all plasmonic counterparts excited in 2D nanoscale geometries, as well as a prominent phase-sensitive response (>3*10(4) deg. of phase per RIU). Combined with a large surface for bioimmobilization provided by the 3D matrix, the proposed sensor architecture promises a new important landmark in the advancement of plasmonic biosensing technology

Deep learning massively accelerates super-resolution localization microscopy

International audienceThe speed of super-resolution microscopy methods based on single-molecule localization, for example, PALM and STORM, is limited by the need to record many thousands of frames with a small number of observed molecules in each. Here, we present ANNA-PALM, a computational strategy that uses artificial neural networks to reconstruct super-resolution views from sparse, rapidly acquired localization images and/or widefield images. Simulations and experimental imaging of microtubules, nuclear pores, and mitochondria show that high-quality, super-resolution images can be reconstructed from up to two orders of magnitude fewer frames than usually needed, without compromising spatial resolution. Super-resolution reconstructions are even possible from widefield images alone, though adding localization data improves image quality. We demonstrate super-resolution imaging of >1,000 fields of view containing >1,000 cells in ∼3 h, yielding an image spanning spatial scales from ∼20 nm to ∼2 mm. The drastic reduction in acquisition time and sample irradiation afforded by ANNA-PALM enables faster and gentler high-throughput and live-cell super-resolution imaging

Perspectives and consensus among international orthopaedic surgeons during initial and mid-lockdown phases of coronavirus disease

With a lot of uncertainty, unclear, and frequently changing management protocols, COVID-19 has significantly impacted the orthopaedic surgical practice during this pandemic crisis. Surgeons around the world needed closed introspection, contemplation, and prospective consensual recommendations for safe surgical practice and prevention of viral contamination. One hundred orthopaedic surgeons from 50 countries were sent a Google online form with a questionnaire explicating protocols for admission, surgeries, discharge, follow-up, relevant information affecting their surgical practices, difficulties faced, and many more important issues that happened during and after the lockdown. Ten surgeons critically construed and interpreted the data to form rationale guidelines and recommendations. Of the total, hand and microsurgery surgeons (52%), trauma surgeons (32%), joint replacement surgeons (20%), and arthroscopy surgeons (14%) actively participated in the survey. Surgeons from national public health care/government college hospitals (44%) and private/semiprivate practitioners (54%) were involved in the study. Countries had lockdown started as early as January 3, 2020 with the implementation of partial or complete lifting of lockdown in few countries while writing this article. Surgeons (58%) did not stop their surgical practice or clinics but preferred only emergency cases during the lockdown. Most of the surgeons (49%) had three-fourths reduction in their total patients turn-up and the remaining cases were managed by conservative (54%) methods. There was a 50 to 75% reduction in the number of surgeries. Surgeons did perform emergency procedures without COVID-19 tests but preferred reverse transcription polymerase chain reaction (RT-PCR; 77%) and computed tomography (CT) scan chest (12%) tests for all elective surgical cases. Open fracture and emergency procedures (60%) and distal radius (55%) fractures were the most commonly performed surgeries. Surgeons preferred full personal protection equipment kits (69%) with a respirator (N95/FFP3), but in the case of unavailability, they used surgical masks and normal gowns. Regional/local anesthesia (70%) remained their choice for surgery to prevent the aerosolized risk of contaminations. Essential surgical follow-up with limited persons and visits was encouraged by 70% of the surgeons, whereas teleconsultation and telerehabilitation by 30% of the surgeons. Despite the protective equipment, one-third of the surgeons were afraid of getting infected and 56% feared of infecting their near and dear ones. Orthopaedic surgeons in private practice did face 50 to 75% financial loss and have to furlough 25% staff and 50% paramedical persons. Orthopaedics meetings were cancelled, and virtual meetings have become the preferred mode of sharing the knowledge and experiences avoiding human contacts. Staying at home, reading, and writing manuscripts became more interesting and an interesting lifestyle change is seen among the surgeons. Unanimously and without any doubt all accepted the fact that COVID-19 pandemic has reached an unprecedented level where personal hygiene, hand washing, social distancing, and safe surgical practices are the viable antidotes, and they have all slowly integrated these practices into their lives. Strict adherence to local authority recommendations and guidelines, uniform and standardized norms for admission, inpatient, and discharge, mandatory RT-PCR tests before surgery and in selective cases with CT scan chest, optimizing and regularizing the surgeries, avoiding and delaying nonemergency surgeries and follow-up protocols, use of teleconsultations cautiously, and working in close association with the World Health Organization and national health care systems will provide a conducive and safe working environment for orthopaedic surgeons and their fraternity and also will prevent the resurgence of COVID-19