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Topic Review
“Singing” Multilayer Ceramic Capacitors and Mitigation Methods
Multilayer Ceramic Capacitors (MLCC) have a major role in modern electronic devices due to their small price and size, large range of capacitance, small ESL and ESR, and good frequency response. Unfortunately, the main dielectric material used for MLCCs, Barium Titanate, makes the capacitors vibrate due to the piezoelectric and electrostrictive effects. This vibration is transferred to the PCB, making it resonate in the audible range of 20 Hz–20 kHz, and in this way the singing capacitors phenomenon occurs. This phenomenon is usually measured with a microphone, to measure the sound pressure level, or with a Laser Doppler Vibrometer (LDV), to measure the vibration. Besides this, other methods are mentioned in the literature, for example, the optical fiber and the active excitation method. There are several solutions to attenuate or even eliminate the acoustic noise caused by MLCC. Specially designed capacitors for low acoustic levels and different layout geometries are only two options found in the literature. To prevent the singing capacitor phenomenon, different simulations can be performed, the harmonic analysis being the most popular technique. 
  • 1.5K
  • 06 Jun 2022
Topic Review
“Small Hepatocytes” in the Liver
Mature hepatocytes (MHs) in an adult rodent liver are categorized into the following three subpopulations based on their proliferative capability: type I cells (MH-I), which are committed progenitor cells that possess a high growth capability and basal hepatocytic functions; type II cells (MH-II), which possess a limited proliferative capability; and type III cells (MH-III), which lose the ability to divide (replicative senescence) and reach the final differentiated state. These subpopulations may explain the liver’s development and growth after birth. Generally, small-sized hepatocytes emerge in mammal livers. The cells are characterized by being morphologically identical to hepatocytes except for their size, which is substantially smaller than that of ordinary MHs. We initially discovered small hepatocytes (SHs) in the primary culture of rat hepatocytes.
  • 118
  • 21 Dec 2023
Topic Review
«Hadron-M» Complex Installation
“Hadron-M complex installation”, which included an ionization-neutron calorimeter with an area of 55 m2 and an absorber thickness of 1244 g/cm2 (out of eight rows of ionization chambers), one row of neutron detectors and two shower systems of scintillation detectors. The effective area of the “Hadron-M” complex installation was about 30,000 m2.
  • 607
  • 27 Feb 2023
Topic Review
(−)-Methyl-Oleocanthal, a New Oleocanthal Metabolite
The antioxidant and anti-inflammatory responses of (−)-methyl-oleocanthal (met-OLE), a new metabolite of the extra virgin olive oil (EVOO) phenolic oleocanthal (OLE), were explored in lipopolysaccharide (LPS)-induced murine peritoneal macrophages. Possible signaling pathways and epigenetic modulation of histones were studied. Met-OLE inhibited LPS-induced intracellular reactive oxygen species (ROS) and nitrite (NO) production and decreased the overexpression of the pro-inflammatory enzymes COX-2, mPGES-1 and iNOS in murine macrophages.
  • 527
  • 13 Jan 2022
Topic Review
(1,3;1,4)-β-D-Glucans
(1,3;1,4)-β-D-Glucans, also named as mixed-linkage glucans, are unbranched non-cellulosic polysaccharides containing both (1,3)- and (1,4)-β-linkages. The linkage ratio varies depending upon species origin and has a significant impact on the physicochemical properties of the (1,3;1,4)-β-D-glucans.
  • 1.4K
  • 24 Sep 2021
Topic Review
(225088) 2007 OR10
(225088) 2007 OR10, proposed to be named Gonggong, is a likely dwarf planet in the Solar System beyond Neptune, and is a member of the scattered disc. It has a highly eccentric and inclined orbit during which it ranges from 33–101 astronomical units (4.9–15.1 billion kilometers) from the Sun. (As of 2019), its distance from the Sun is 88 AU (1.32×1010 km; 8.2×109 mi), and it is the sixth-farthest known Solar System object. 2007 OR10 is in a 3:10 orbital resonance with Neptune, in which it completes three orbits around the Sun for every ten orbits completed by Neptune. 2007 OR10 was discovered in July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz at the Palomar Observatory, and the discovery was announced in January 2009. At 1,230 km (760 mi) in diameter, 2007 OR10 is approximately the size of Pluto's moon Charon, and is the fifth-largest known trans-Neptunian object in the Solar System. It is sufficiently massive to be gravitationally rounded, thereby qualifying for dwarf planet status. Its large mass also makes retention of a tenuous atmosphere of methane just possible, though such an atmosphere would slowly escape into space. 2007 OR10 is currently the largest known body in the Solar System without an official name, but in 2019, the discoverers hosted an online poll for the general public to help choose a name for the object, and the name Gonggong won. The winning name is derived from Gonggong, a Chinese water god responsible for chaos, floods and the tilt of the Earth. 2007 OR10 is red in color, likely due to the presence of organic compounds called tholins on its surface. Water ice is also present on its surface, which hints at a brief period of cryovolcanic activity in the distant past. 2007 OR10 rotates slowly compared to other trans-Neptunian objects, which typically have rotation periods less than 12 hours, which may be due to its natural satellite, provisionally designated S/2010 (225088) 1.
  • 1.2K
  • 02 Dec 2022
Topic Review
(469219) 2016 HO3
(469219) 2016 HO3 is a micro-asteroid, fast rotator and near-Earth object of the Apollo group, approximately 41 meters in diameter. It is currently the smallest, closest, and most stable (known) quasi-satellite of Earth. The asteroid was discovered by Pan-STARRS at Haleakala Observatory on 27 April 2016.
  • 864
  • 03 Nov 2022
Topic Review
(486958) 2014 MU69
(486958) 2014 MU69, previously designated PT1 and 1110113Y, and nicknamed Ultima Thule by the New Horizons team, is a trans-Neptunian object from the Kuiper belt located in the outermost regions of the Solar System. It was discovered by astronomers using the Hubble Space Telescope on 26 June 2014. The irregular shaped classical Kuiper belt object is a suspected contact binary or close binary system and measures approximately 30 kilometers (19 miles) in diameter. In August 2015, this object was selected as the next target for the New Horizons probe shortly after it had visited Pluto. The flyby will occur on 1 January 2019, which will make it the farthest object in the Solar System ever to be visited by a spacecraft. After four course changes in October and November 2015, New Horizons is on course toward 2014 MU69. On 13 March 2018, NASA announced that (486958) 2014 MU69 would receive the nickname Ultima Thule. The decision was based on the results of a public voting campaign. Ultima Thule /ˈθuːliː/, or Ultima for short, serves as an unofficial name for the object until the IAU decides on an official name at some point after the flyby.
  • 337
  • 19 Oct 2022
Topic Review
(594913) 2020 AV2
(594913) 2020 AV2, provisionally designated: 2020 AV2, is a large near-Earth asteroid discovered by the Zwicky Transient Facility on 4 January 2020. It is the first asteroid discovered to have an orbit completely within Venus's orbit, and is thus the first and only known member of the inner-Venusian provisionally-named Vatira population of Atira-class asteroids. 2020 AV2 has the smallest known aphelion and third-smallest known semi-major axis among all asteroids. With an absolute magnitude approximately 16.2, the asteroid is expected to be larger than 1 km in diameter.
  • 504
  • 21 Oct 2022
Topic Review
(6545) 1986 TR6
(6545) 1986 TR6, provisional designation 1986 TR6, is a Jupiter trojan from the Greek camp, approximately 53 kilometers (33 miles) in diameter. It was discovered on 5 October 1986, by Slovak astronomer Milan Antal at the Piwnice Astronomical Observatory in Poland. The dark D-type asteroid has a rotation period of 16.3 hours and belongs to the 90 largest Jupiter trojans. It has not been named since its numbering in September 1995.
  • 274
  • 09 Nov 2022
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