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Topic Review
Label-Free Multiphoton Microscopy
Label-free microscopy methods rely on photophysical processes to generate signals through specific interactions with biological molecules and offer great potential for basic research and clinical applications.
  • 513
  • 28 Apr 2021
Topic Review
Laboratory B in Sunguľ
Laboratory B in Sunguľ was one of the laboratories under the 9th Chief Directorate of the NKVD (MVD after 1946) that contributed to the Soviet atomic bomb project. It was created in 1946 and closed in 1955, when some of its personnel were merged with the second Soviet nuclear design and assembly facility. It was run as a sharashka – a secret scientific facility run as a prison. Laboratory B employed German scientists from 1947 to 1953. It had two scientific divisions, radiochemistry and radiobiophysics; the latter was headed by the world-renowned geneticist N. V. Timofeev-Resovskij. For two years, the renowned German chemist, Nikolaus Riehl was the scientific director.
  • 423
  • 25 Oct 2022
Topic Review
Laboratory B in Sungul’
Laboratory B in Sungul' was one of the laboratories under the 9th Chief Directorate of the NKVD (MVD after 1946) that contributed to the Soviet atomic bomb project. It was created in 1946 and closed in 1955, when some of its personnel were merged with the second Soviet nuclear design and assembly facility. It was run as a sharashka – a secret scientific facility run as a prison. Laboratory B employed German scientists from 1947 to 1953. It had two scientific divisions, radiochemistry and radiobiophysics; the latter was headed by the world-renowned geneticist N. V. Timofeev-Resovskij. For two years, the renowned German chemist, Nikolaus Riehl was the scientific director.
  • 371
  • 08 Nov 2022
Topic Review
Laccases in Phenolic Compound Detection and Quantification
Phenolic compounds (PheCs) are particularly relevant in many different frameworks due to their pro-oxidant and antioxidant activities. In fact, on the one hand, they are considered very dangerous pro-oxidant agents that can be present in the environment as pollutants in wastewater and soil from different industrial and agricultural industries. On the other hand, the antioxidant influence of PheCs available in natural products (including foods) is nowadays considered essential for preserving human health. Conventional techniques for detecting PheCs present some disadvantages, such as requiring expensive instrumentation and expert users and not allowing in situ measurements. This is the reason why there is a high interest in the development of simple, sensitive, specific, and accurate sensing methods for PheCs. Enzymes are often used for this purpose, and laccases with unique optical properties are adopted as bio-elements for sensing schemes. 
  • 198
  • 06 Dec 2023
Topic Review
Lagrangian Point
In celestial mechanics, the Lagrangian points (/ləˈɡrɑːndʒiən/ also Lagrange points, L-points, or libration points) are the points near two large bodies in orbit where a smaller object will maintain its position relative to the large orbiting bodies. At other locations, a small object would go into its own orbit around one of the large bodies, but at the Lagrangian points the gravitational forces of the two large bodies, the centripetal force of orbital motion, and (for certain points) the Coriolis acceleration all match up in a way that cause the small object to maintain a stable or nearly stable position relative to the large bodies. There are five such points, labeled L1 to L5, all in the orbital plane of the two large bodies, for each given combination of two orbital bodies. For instance, there are five Lagrangian points L1 to L5 for the Sun–Earth system, and in a similar way there are five different Lagrangian points for the Earth–Moon system. L1, L2, and L3 are on the line through the centers of the two large bodies, while L4 and L5 each act as the third vertex of an equilateral triangle formed with the centers of the two large bodies. L4 and L5 are stable, which implies that objects can orbit around them in a rotating coordinate system tied to the two large bodies. Several planets have trojan satellites near their L4 and L5 points with respect to the Sun. Jupiter has more than a million of these trojans. Artificial satellites have been placed at L1 and L2 with respect to the Sun and Earth, and with respect to the Earth and the Moon. The Lagrangian points have been proposed for uses in space exploration.
  • 2.5K
  • 17 Nov 2022
Topic Review
Langmuir–Blodgett Graphene-Based Films
The prevalence of photosynthesis, as the major natural solar energy transduction mechanism or biophotovoltaics (BPV), has always intrigued mankind. The development of high performance and durable BPVs is dependent on upgraded anode materials with electrochemically dynamic nanostructures. However, the current challenges in the optimization of anode materials remain significant barriers towards the development of commercially viable technology. Langmuir–Blodgett (LB) film has been substantiated as an efficacious film-forming technique to tackle the above limitations of algal BPVs; however, the aforesaid technology remains vastly untapped in BPVs.
  • 631
  • 08 Mar 2022
Topic Review
Large Extra Dimension
In particle physics and string theory (M-theory), the ADD model, also known as the model with large extra dimensions (LED), is a model framework that attempts to solve the hierarchy problem. (Why is the force of gravity so weak compared to the electromagnetic force and the other fundamental forces?) The model tries to explain this problem by postulating that our universe, with its four dimensions (three spatial ones plus time), exists on a so called membrane floating in 11-dimensional space. It is then suggested that the other forces of nature (the electromagnetic force, strong interaction, and weak interaction) operate within this membrane and its four dimensions, while gravity can operate across all 11 dimensions. This would explain why gravity is very weak compared to the other fundamental forces. This is a radical theory given that the other 7 dimensions, which we do not observe, previously have been assumed to be very small (about a planck-length), while this theory asserts that they might be very large. The model was proposed by Nima Arkani-Hamed, Savas Dimopoulos, and Gia Dvali in 1998. Attempts to test the theory are executed by smashing together two protons in the Large Hadron Collider so that they disperse and release elementary particles. If a postulated graviton appeared after a collision, for such a particle to disappear, and its disappearance be observed, that would suggest that the graviton had escaped into other dimensions beyond our universe's observable four. No experiments from the Large Hadron Collider have been decisive thus far. However, the operation range of the LHC (13 TeV collision energy) covers only a small part of the predicted range in which evidence for LED would be recorded (a few TeV to 1016 TeV). This suggests that the theory might be more thoroughly tested with advanced technology.
  • 398
  • 01 Dec 2022
Topic Review
Large Strategic Science Missions
NASA's Large Strategic Science Missions, formerly known as Flagship missions or Flagship-class missions, are the costliest and most capable NASA science spacecraft. Flagship missions exist within all four divisions of NASA's Science Mission Directorate: the astrophysics, Earth science, heliophysics and planetary science divisions. "Large" refers to the budget of each mission, typically the most expensive mission in the scientific discipline. Within the Astrophysics Division and the Planetary Science Division, the large strategic missions are usually in excess of $1 billion. Within Earth Science Division and Heliophysics Division, the large strategic missions are usually in excess of $500 million. "Strategic" refers to their role advancing multiple strategic priorities set forth in plans such as the Decadal Surveys. "Science" marks these missions as primarily scientific in nature, under the Science Mission Directorate (SMD), as opposed to, e.g., human exploration missions under the Human Exploration and Operations Mission Directorate (HEOMD). The lines can be blurred, as when the Lunar Reconnaissance Orbiter began as a directed mission from the HEOMD, and was later transferred to the SMD. Flagship missions are not under the purview of any larger "Flagship Program", unlike, e.g., Discovery-class missions that are under the purview of the Discovery Program. Unlike these competed classes that tender proposals through a competitive selection process, the development of Flagship missions is directed to a specific institution — usually a NASA center or the Jet Propulsion Laboratory — by the Science Mission Directorate. Flagship missions are developed ad-hoc, with no predetermined launch cadence or uniform budget size. Flagship missions are always Class A missions: high priority, very low risk.
  • 542
  • 17 Nov 2022
Topic Review
Large Synoptic Survey Telescope
The Large Synoptic Survey Telescope (LSST) is a wide-field survey reflecting telescope with an 8.4-meter primary mirror, currently under construction, that will photograph the entire available sky every few nights. The word synoptic is derived from the Greek words σύν (syn "together") and ὄψις (opsis "view"), and describes observations that give a broad view of a subject at a particular time. The telescope uses a novel 3-mirror design, a variant of three-mirror anastigmat, which allows a compact telescope to deliver sharp images over a very wide 3.5-degree diameter field of view. Images will be recorded by a 3.2-gigapixel CCD imaging camera, the largest digital camera ever constructed. The telescope is located on the El Peñón peak of Cerro Pachón, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile , alongside the existing Gemini South and Southern Astrophysical Research Telescopes. The LSST Base Facility is located about 100 kilometres (62 mi) away by road, in the town of La Serena. The LSST was proposed in 2001, and construction of the mirror began (with private funds) in 2007. LSST then became the top-ranked large ground-based project in the 2010 Astrophysics Decadal Survey, and the project officially began construction 1 August 2014 when the National Science Foundation (NSF) authorized the FY2014 portion ($27.5 million) of its construction budget. The ceremonial laying of the first stone was performed on 14 April 2015. Site construction began on April 14, 2015, with engineering first light anticipated in 2019, science first light in 2021, and full operations for a ten-year survey commencing in January 2022. LSST, unlike almost all previous large astronomical observatories, has committed to making all data public as soon as it is taken. In their words "By providing immediate public access to all the data it obtains, it will provide everyone, the professional and the “just curious” alike, a deep and frequent window on the entire sky."
  • 842
  • 10 Nov 2022
Topic Review
Large UV Optical Infrared Surveyor
The Large UV Optical Infrared Surveyor (LUVOIR) is a multi-wavelength space observatory concept being developed by the Goddard Space Flight Center and proposed for the Decadal Survey Concept Study started in January 2016. The concept is based on a mirror from 8 m to 18 m in diameter, and covering the ultraviolet, visible and infrared wavelengths. It would be a Large Strategic Science Mission and be up for selection sometime after 2020. LUVOIR is a set of goals and requirements for a space telescope, but is not a specific design. More concrete proposals have their own names, such as ATLAST and HDST. One of those will be selected to become LUVOIR.
  • 416
  • 23 Nov 2022
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