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Topic Review
Biosensing Applications of GLAD-Fabricated Nanostructures
Glancing angle deposition (GLAD) is a technique for the fabrication of sculpted micro- and nanostructures under the conditions of oblique vapor flux incident and limited adatom diffusion. GLAD-based nanostructures are emerging platforms with broad sensing applications due to their high sensitivity, enhanced optical and catalytic properties, periodicity, and controlled morphology. GLAD-fabricated nanochips and substrates for chemical and biosensing applications are replacing conventionally used nanomaterials due to their broad scope, ease of fabrication, controlled growth parameters, and hence, sensing abilities.
  • 444
  • 13 Dec 2022
Topic Review
Biosensing Using SERS Active Gold Nanostructures
Surface-enhanced Raman spectroscopy (SERS) has become a powerful tool for biosensing applications owing to its fingerprint recognition, high sensitivity, multiplex detection, and biocompatibility. This review provides an overview of the most significant aspects of SERS for biomedical and biosensing applications. 
  • 792
  • 01 Nov 2021
Topic Review
Biospeckle Analysis and Biofilm Electrostatic Tests
The development of more sensitive methodologies, capable of quickly detecting and monitoring a microbial population present in a specific biological matrix, as well as performing to allow for the study of all its metabolic changes (e.g., during the formation of biofilm) to occur, is an essential requirement for both well-being and the food industry. Two techniques, in particular, have gained the attention of scientists: The first is “biospeckle”, an optical technique representing an innovative tool for applications in food quality, food safety, and nutraceuticals.  A second technique with great chances is the “biofilm electrostatic test” (BET). BET undoubtedly represents a fast, simple, and highly reproducible tool suitable for admitting the evaluation of the in vitro bacterial capacity in order to adhere through an electrostatic interaction with a pyro-electrified carrier after only 2 h of incubation.
  • 405
  • 03 Dec 2021
Topic Review
Bismuth Indium
The elements bismuth and indium have relatively low melting points when compared to other metals, and their alloy Bismuth Indium is classified as a fusible alloy. It has a melting point lower than the eutectic point of the tin lead alloy. The most common application of the alloy is as a low temperature solder, which can also contain, besides Bismuth and Indium, lead, cadmium and tin.
  • 595
  • 10 Nov 2022
Topic Review
Black Belt (U.S. Region)
The Black Belt is a region of the Southern United States. The term originally described the prairies and dark fertile soil of central Alabama and northeast Mississippi. Because this area in the 19th century was historically developed for cotton plantations based on enslaved African American labor, the term became associated with these conditions. It was generally applied to a much larger agricultural region in the Southern United States, which was characterized by a history of cotton plantation agriculture in the 19th century and a high percentage of African Americans outside metropolitan areas. The enslaved peoples were freed after the American Civil War, and many continued to work in agriculture afterward. Their descendants make up much of the African-American population of the United States. During the first half of the 19th Century, as many as one million enslaved Africans were transported through sales in the domestic slave trade to the Deep South in a forced migration to work as laborers for the region's cotton plantations. After having lived enslaved for several generations in the area, many remained as rural workers, tenant farmers and sharecroppers after the Civil War and emancipation. Beginning in the early 20th century and up to 1970, a total of six million black people left the South in the Great Migration to find work and other opportunities in the industrial cities of the Northeast, Midwest, and West. Because of relative isolation and lack of economic development, the rural communities in the Black Belt have historically faced acute poverty, rural exodus, inadequate education programs, low educational attainment, poor health care, urban decay, substandard housing, and high levels of crime and unemployment. In December 2017, the Special Rapporteur of the Office of the United Nations High Commissioner for Human Rights declared that Alabama was the most impoverished area in the developed world. Given the history of decades of racial segregation into the late 20th century, African-American residents have been the most disproportionately affected, although these problems apply broadly to all ethnic groups in the rural Black Belt. The region and its boundaries have varying definitions, but it is generally considered a band through the center of the Deep South, although stretching from as far north as Delaware to as far west as East Texas.
  • 2.8K
  • 31 Oct 2022
Topic Review Video
Black Hole
Black holes are the celestial objects existing at the center of every galaxy. They can currently only be described by their spin, charge, and angular momentum, with other attributes derived from the basic properties. The existence of black holes was first predicted by German physicist and astronomer Karl Schwarzschild in 1916, with the exact solutions to Einstein's field equations of general relativity one year after its publication. Finnish physicist Gunnar Nordström proposed a theory of gravity and electromagnetism with four spatial dimensions in 1914, and later developed into the stationary charged black hole in 1918.
  • 544
  • 15 Oct 2023
Topic Review
Black Holes and Quantum Mechanics
Mass and spin distributions of stellar mass black holes (BH) are important sources of information on the formation mechanism and the evolution of galaxies. The birth of a stellar-mass BH, ranging in the interval ~5–150 M⊙, is due to the spectacular phase of a massive star’s core collapse, an event involving the emission of multi-messenger signals such as neutrinos, GW’s and electromagnetic radiation in several bands.
  • 357
  • 03 Nov 2022
Topic Review
Bloch Wave
A Bloch wave (also called Bloch state or Bloch function or Bloch wavefunction), named after Swiss physicist Felix Bloch, is a kind of wave function which can be written as a plane wave modulated by a periodic function. By definition, if a wave is a Bloch wave, its wavefunction can be written in the form: where [math]\displaystyle{ \mathbf{r} }[/math] is position, [math]\displaystyle{ \psi }[/math] is the Bloch wave, [math]\displaystyle{ u }[/math] is a periodic function with the same periodicity as the crystal, the wave vector [math]\displaystyle{ \mathbf{k} }[/math] is the crystal momentum vector, [math]\displaystyle{ \mathrm{e} }[/math] is Euler's number, and [math]\displaystyle{ \mathrm{i} }[/math] is the imaginary unit. Bloch waves are important in solid-state physics, where they are often used to describe an electron in a crystal. This application is motivated by Bloch's theorem, which states that the energy eigenstates for an electron in a crystal can be written as Bloch waves (more precisely, it states that the electron wave functions in a crystal have a basis consisting entirely of Bloch wave energy eigenstates). This fact underlies the concept of electronic band structures. These Bloch wave energy eigenstates are written with subscripts as [math]\displaystyle{ \psi_{n\mathbf{k}} }[/math], where [math]\displaystyle{ n }[/math] is a discrete index, called the band index, which is present because there are many different Bloch waves with the same [math]\displaystyle{ \mathbf{k} }[/math] (each has a different periodic component [math]\displaystyle{ u }[/math]). Within a band (i.e., for fixed [math]\displaystyle{ n }[/math]), [math]\displaystyle{ \psi_{n\mathbf{k}} }[/math] varies continuously with [math]\displaystyle{ \mathbf{k} }[/math], as does its energy. Also, for any reciprocal lattice vector [math]\displaystyle{ \mathbf{K} }[/math], [math]\displaystyle{ \psi_{n\mathbf{k}}=\psi_{n(\mathbf{k+K})} }[/math]. Therefore, all distinct Bloch waves occur for values of [math]\displaystyle{ \mathbf{k} }[/math] which fall within the first Brillouin zone of the reciprocal lattice.
  • 3.6K
  • 30 Nov 2022
Topic Review
Blue Light and Eye Damage
Personal digital devices, emitting high-energy light, namely in the blue wavelength, have raised concerns about possible harmful effects on users’ eyes. Scientific research history has shown a relationship between exposure to blue light and changes in ocular structures.
  • 340
  • 18 May 2023
Topic Review
Bohr–van Leeuwen Theorem
The Bohr–van Leeuwen theorem states that when statistical mechanics and classical mechanics are applied consistently, the thermal average of the magnetization is always zero. This makes magnetism in solids solely a quantum mechanical effect and means that classical physics cannot account for diamagnetism.
  • 1.9K
  • 21 Oct 2022
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