Cuticular nanostructures found in insects effectively manage light for light polarization, structural color, or optical index matching within an ultrathin natural scale. These nanostructures are ...mainly dedicated to manage incoming light and recently inspired many imaging and display applications. A bioluminescent organ, such as a firefly lantern, helps to out-couple light from the body in a highly efficient fashion for delivering strong optical signals in sexual communication. However, the cuticular nanostructures, except the light-producing reactions, have not been well investigated for physical principles and engineering biomimetics. Here we report a unique observation of high-transmission nanostructures on a firefly lantern and its biological inspiration for highly efficient LED illumination. Both numerical and experimental results clearly reveal high transmission through the nanostructures inspired from the lantern cuticle. The nanostructures on an LED lens surface were fabricated by using a large-area nanotemplating and reconfigurable nanomolding with heat-induced shear thinning. The biologically inspired LED lens, distinct from a smooth surface lens, substantially increases light transmission over visible ranges, comparable to conventional antireflection coating. This biological inspiration can offer new opportunities for increasing the light extraction efficiency of high-power LED packages.
Introduction: Given the sheer number and significance of festivals and events in the Indian context, Salaam Mumbai Foundation (SMF) strategically utilized these social and cultural platforms to ...disseminate tobacco control messages to reach out to large numbers of people across ages and socio-economic strata. Objectives: Festivals are an effective platform to reach people and convey messages on tobacco prevention and control. Methods: Since 2016, SMF has conducted mass campaigns during festivals and events such as the Independence Day, Rakshabandhan, Ganeshotsav, Holi, and Diwali to reach out and work with school and community-level stakeholders as well as government authorities and decision makers. Results: SMF worked with government schools to integrate anti-tobacco slogans and songs in these Independence day rallies and issued a letter of support by the health department of Maharashtra. Nearly 10000 schools participated in this campaign, reaching around 10 lakh people in Maharashtra. Rakshabandhan is a widely celebrated cultural festival in which sisters tie a Rakhi (band) on their brothers’ wrist to symbolise the love and protection between siblings. This activity was conducted in 13 districts of Maharashtra where 125 students and teachers met 52 decision makers. During Ganeshotsav, in all 28 districts of Maharashtra, SMF’s partner teachers and NGOs decorated the Ganapati pandal with anti-tobacco posters and also played anti-tobacco messages during daily prayers (aarti). Public awareness activities including videos, anti-tobacco songs and posters were displayed in the pandals. During Diwali festival sensitization of Anti-tobacco campaign was done through the medium of Rangoli and lanterns. During the occasion of holi, In 5 villages, SMF sensitized 1500 people on tobacco use. Furthermore, 2100 schools participated in this activity and reached 1 lakh people. Conclusion(s): Students and teachers are important stakeholders and can deliver messages on such platforms.
The orbital angular momentum (OAM) spatial degree of freedom of light has been widely explored in many applications, including telecommunications, quantum information, and light-based ...micromanipulation. The ability to separate and distinguish between the different transverse spatial modes is called mode sorting or mode demultiplexing, and it is essential to recover the encoded information in such applications. An ideal d mode sorter should be able to faithfully distinguish between the different d spatial modes, with minimal losses, and have d outputs and fast response times. All previous mode sorters rely on bulk optical elements, such as spatial light modulators, which cannot be quickly tuned and have additional losses if they are to be integrated with optical fiber systems. Here, we propose and experimentally demonstrate, to the best of our knowledge, the first all-in-fiber method for OAM mode sorting with ultrafast dynamic reconfigurability. Our scheme first decomposes the OAM mode in-fiber-optical linearly polarized (LP) modes and then interferometrically recombines them to determine the topological charge, thus correctly sorting the OAM mode. In addition, our setup can also be used to perform ultrafast routing of the OAM modes. These results show a novel and fiber-integrated form of optical spatial mode sorting that can be readily used for many new applications in classical and quantum information processing.
Photonic technologies offer numerous functionalities that can be used to realize astrophotonic
instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large
...Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a
complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical
advantages for instrument development, including extreme miniaturization when operating at the
diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the
small footprint, and high replicability offering significant cost savings. Numerous astrophotonic
technologies have been developed to address shortcomings of conventional instruments to date,
including for example the development of photonic lanterns to convert from multimode inputs to
single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the
atmosphere, complex beam combiners to enable long baseline interferometry with for example,
ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers.
Despite these successes, the facility implementation of photonic solutions in astronomical
instrumentation is currently limited because of (1) low throughputs from coupling to fibers,
coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling
to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient
integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas
that need further development. We outline the challenges and advances needed across those areas
covering design tools, simulation capabilities, fabrication processes, the need for entirely new
components, integration and hybridization and the characterization of devices. To realize these
advances the astrophotonics community will have to work cooperatively with industrial partners
who have more advanced manufacturing capabilities. With the advances described herein,
multi-functional integrated instruments will be realized leading to novel observing capabilities for
both ground and space based platforms, enabling new scientific studies and discoveries.
Four new quasi-1D Ni
-lantern chain complexes of the form Ni
(SOCR)
(L)
(R = Ph, L = DABCO (1); R = Ph, L = pyz (2); R = CH
, L = DABCO (3); R = CH
, L = pyz (4)) were prepared from the reaction of ...Ni
(SOCR)
(EtOH), R = CH
or Ph, with the N,N'-donor bridging ligands pyrazine (pyz) or 1,4-diazabicyclo2.2.2octane (DABCO). Reaction of Ni
(tba)
(EtOH), (tba = thiobenzoate) with the mono-N donor ligand quinuclidine (quin) gave the discrete Ni
-lantern complex Ni
(tba)
(quin) (5), whereas reaction with pyridine led to fragmentation of the lantern and formation of the known Ni(tba)
(py)
(6). Single-crystal X-ray diffraction reveals 2-4 to be 1D chain complexes comprising DABCO or pyz ligands which bridge the Ni
-lantern units. Complex 5 forms dimers through two equivalent NiS interactions. The Ni-Ni distances within the Ni
-lanterns are 2.5316(18)-2.595(2) Å for the 1D chain complexes 2-4, and 2.5746(4) Å in the dimeric complex 5, respectively. Comparing the solid state magnetism of 5 to precursor Ni
(tba)
(EtOH) demonstrates a change in coupling upon change of capping ligand. Meanwhile, chains 1-4 exhibit magnetic properties consistent with an S = 1 system, due to a mixed valent system where the two Ni centers differ in spin state, while 5 possesses two S = 1 Ni(ii) centers. DFT calculations confirm low-spin S = 0 {NiS
} and high-spin S = 1 {NiO
} centers in each lantern. Fits to the magnetic susceptibility data of the chains suggest a weak antiferromagnetic mean field interaction is present that is largely 1-D in nature, though neither pyrazine nor DABCO promote significant magnetic interaction between neighboring Ni
-lanterns.
Heparan sulfate (HS) regulates a wide range of biological events, including blood coagulation, cancer development, cell differentiation, and viral infections. It is generally recognized that ...structures of HS can critically impact its biological functions. However, with complex structures of naturally existing HS, systematic investigations into the structure-activity relationship (SAR) of HS and efforts to unlock their "sulfation code" have been largely limited due to the challenges in preparing diverse HS oligosaccharide sequences. Herein, we report an automated machine-aided solid-phase strategy that significantly expedited the assembly of HS disaccharides. The key strategically protected advanced disaccharide intermediates were immobilized onto Synphase lanterns. Divergent deprotections and sulfations of the disaccharides were achieved on the lanterns in high yields. In addition, the full synthetic process was automated, enabling the reproducible production of HS disaccharides. A library of 16 HS disaccharides with diverse sulfation patterns was prepared via this method. Compared to the traditional HS synthesis, this new strategy led to a reduction of 50% of the number of synthetic steps and over 80% of the number of column purification steps needed from the disaccharide intermediates, significantly improving the overall synthetic efficiency. The potential utility of the method was highlighted in a microarray study using the synthetic HS disaccharide library with fibroblast growth factor-2 (FGF-2), which yielded insights into the SAR of HS/FGF-2 interactions.
Cycling has a range of benefits as is recognised by national and international policies aiming to increase cycling rates. Darkness acts as a barrier to people cycling, with fewer people cycling ...after-dark when seasonal and time-of-day factors are accounted for. This paper explores whether road lighting can reduce the negative impact of darkness on cycling rates. Changes in cycling rates between daylight and after-dark were quantified for 48 locations in Birmingham, United Kingdom, by calculating an odds ratio. These odds ratios were compared against two measures of road lighting at each location: 1) Density of road lighting lanterns; 2) Relative brightness as estimated from night-time aerial images. Locations with no road lighting showed a significantly greater reduction in cycling after-dark compared with locations that had some lighting. A nonlinear relationship was found between relative brightness at a location at night and the reduction in cyclists after-dark. Small initial increases in brightness resulted in large reductions in the difference between cyclist numbers in daylight and after-dark, but this effect reached a plateau as brightness increased. These results suggest only a minimal amount of lighting can promote cycling after-dark, making it an attractive mode of transport year-round.
Extreme adaptive optics (AO) systems are now in operation across the globe. These systems, capable of high order wavefront correction, deliver Strehl ratios of ~90% in the near-infrared. Originally ...intended for the direct imaging of exoplanets, these systems are often equipped with advanced coronagraphs that suppress the on-axis-star, interferometers to calibrate wavefront errors, and low order wavefront sensors to stabilize any tip/tilt residuals to a degree never seen before. Such systems are well positioned to facilitate the detailed spectroscopic characterization of faint substellar companions at small angular separations from the host star. Additionally, the increased light concentration of the point-spread function and the unprecedented stability create opportunities in other fields of astronomy as well, including spectroscopy. With such Strehl ratios, efficient injection into single-mode fibers (SMFs) or photonic lanterns becomes possible. With diffraction-limited components feeding the instrument, calibrating a spectrograph’s line profile becomes considerably easier, as modal noise or imperfect scrambling of the fiber output are no longer an issue. It also opens up the possibility of exploiting photonic technologies for their advanced functionalities, inherent replicability, and small, lightweight footprint to design and build future instrumentation. In this work, we outline how extreme AO systems will enable advanced photonic and diffraction-limited technologies to be exploited in spectrograph design and the impact it will have on spectroscopy. We illustrate that the precision of an instrument based on these technologies, with light injected from an efficient SMF feed would be entirely limited by the spectral content and stellar noise alone on cool stars and would be capable of achieving a radial velocity precision of several m/s; the level required for detecting an exo-Earth in the habitable zone of a nearby M-dwarf.
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