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Topic Review
Ultrafast Phase Transitions in (001) Si
Researchers demonstrate an ultrafast (<0.1 ps) reversible phase transition in silicon (Si) under ultrafast pressure loading using molecular dynamics. Si changes its structure from cubic diamond to β-Sn on the shock-wave front. The phase transition occurs when the shock-wave pressure exceeds 11 GPa. 
  • 395
  • 04 Mar 2022
Topic Review
Ultrafast Laser Spectroscopy
Ultrafast laser spectroscopy is a spectroscopic technique that uses ultrashort pulse lasers for the study of dynamics on extremely short time scales (attoseconds to nanoseconds). Different methods are used to examine dynamics of charge carriers, atoms and molecules. Many different procedures have been developed spanning different time scales and photon energy ranges; some common methods are listed below.
  • 500
  • 15 Nov 2022
Topic Review
Ultrafast Laser in Orthopedic Surgery
The potential of ultrafast lasers (pico- to femtosecond) in orthopedics-related procedures has been studied extensively for clinical adoption. As compared to conventional laser systems with continuous wave or longer wave pulse, ultrafast lasers provide advantages such as higher precision and minimal collateral thermal damages. Translation to surgical applications in the clinic has been restrained by limitations of material removal rate and pulse average power, whereas the use in surface texturing of implants has become more refined to greatly improve bioactivation and osteointegration within bone matrices.
  • 651
  • 07 May 2022
Topic Review
Ultrafast Fiber Technologies for Compact Laser Wake Field
Technologies, performances and maturity of ultrafast fiber lasers and fiber delivery of ultrafast pulses are used for the medical deployment of laser-wake-field acceleration (LWFA). The compact ultrafast fiber lasers produce intense laser pulses with flexible hollow-core fiber delivery to facilitate electron acceleration in the laser-stimulated wake field near treatment site, empowering endoscopic LWFA brachytherapy. With coherent beam combination of multiple fiber amplifiers, the advantages of ultrafast fiber lasers are further extended to bring in more capabilities in compact LWFA applications.
  • 577
  • 08 Jul 2022
Topic Review
Ultracentrifugation Techniques for Nanoparticles Ordering
A centrifugal field can provide an external force for the ordering of nanoparticles. Especially with the knowledge from in-situ characterization by analytical (ultra)centrifugation, nanoparticle ordering can be rationally realized in preparative (ultra)centrifugation. This study summarizes the work back to the 1990s, where intuitive use of centrifugation was achieved for the fabrication of colloidal crystals to the very recent work where analytical (ultra)centrifugation is employed to tailor-make concentration gradients for advanced materials. This review is divided into three main parts. In the introduction part, the history of ordering microbeads in gravity is discussed and with the size of particles reduced to nanometers, a centrifugal field is necessary. In the next part, the research on the ordering of nanoparticles in analytical and preparative centrifugation in recent decades is described. In the last part, the applications of the functional materials, fabricated from centrifugation-induced nanoparticle superstructures are briefly discussed.
  • 767
  • 05 Feb 2021
Topic Review
Ultra-Wideband Antenna on a Polymeric Substrate
The design, simulation, realization, and measurement of an ultra-wideband (UWB) antenna on a polymeric substrate have been realized. The UWB antenna was prepared using conventional technology, such as copper etching; inkjet printing, which is regarded as a modern and progressive nano-technology; and polymer thick-film technology in the context of screen-printing technology. The thick-film technology-based UWB antenna has a bandwidth of 3.8 GHz, with a central frequency of 9 GHz, and a frequency range of 6.6 to 10.4 GHz. In addition to a comparison of the technologies described, the results show that the mesh of the screens has a significant impact on the quality of the UWB antenna when utilizing polymeric screen-printing pastes.
  • 654
  • 22 Apr 2022
Topic Review
Ultra-Reliable Low-Latency V2X Communications
Vehicular communication is a promising technology that has been announced as a main use-case of the fifth-generation cellular system (5G). Vehicle-to-everything (V2X) is the vehicular communication paradigm that enables the communications and interactions between vehicles and other network entities, e.g., road-side units (RSUs). This promising technology faces many challenges related to reliability, availability and security of the exchanged data. 
  • 966
  • 07 Jan 2022
Topic Review
Ultra-processed Foods
Ultra-processed foods were first defined by Dr. Carlos Monteiro in 2009 through the NOVA classification. Briefly, they are characterized in their formulation by the addition of cosmetic ingredients and/or additives for mainly industrial use - and having undergone an excessive processing  - to imitate, exacerbate, mask or restore sensory properties (aroma, texture, taste and color). It can also be very denaturing technological processes directly applied to the food (cooking-extrusion, puffing, etc.). They are food and drink products that have undergone specified types of food processing, usually by transnational and other very large 'Big food' corporations. These foods are designed to be 'convenient, eaten on the go, hyperpalatable and appealing to consumers, and, most importantly, the most profitable segment of Big Food companies’ portfolios because of these foods’ low-cost ingredients'. The NOVA-derived Siga score propose a complementary definition more focused ont the degradation of the food/ingredient matrix effect: "An ultra-processed food is characterized by the presence in its list of ingredients of at least one substance that is itself ultra-processed, called a marker of ultra-processing (MUP). These MUPs are obtained by synthesis, or by a succession of physical, chemical and/or biological processes applied to natural raw materials and which lead to a strong degradation compared to their original matrix".
  • 3.0K
  • 29 Oct 2020
Topic Review
Ultra-Processed Food Consumption and Risk of Diabetes Mellitus
Ultra-processed foods (UPFs) are products that have undergone a series of industrial processes, including physical, biological, or chemical processes, coupled with the use of additives such as colorings, emulsifiers, and preservatives. UPF consumption has grown dramatically over the last few decades worldwide. This growth is accompanied by the increasing prevalence of non-communicable diseases (NCDs) such as cardiovascular diseases, hypertension, and type 2 diabetes. UPFs represent three main health concerns: (i) they are generally high in non-nutritive compounds such as sugars, sodium, and trans fat and low in nutritional compounds such as proteins and fibers, (ii) they contain different types of additives that may cause severe health issues, and (iii) they are presented in packages made of synthetic materials that may also cause undesirable health side-effects.
  • 900
  • 15 Jun 2022
Topic Review
Ultra-Processed Food Availability
UPF are described as “processed ingredients typically combined with the sophisticated use of additives to make them edible, palatable and habit forming”.
  • 635
  • 04 Aug 2021
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