Topic Review
Well-Differentiated Thyroid Cancer
Well-differentiated thyroid carcinoma (WDTC) is a slow-growing cancer with a good prognosis, but may show extraglandular progression involving the invasion of tumor-adjacent tissues, such as the trachea, esophagus, and recurrent laryngeal nerve. Tracheal invasion by WDTC is infrequent. Since this condition is rare, relevant high-level evidence about it is lacking. Tracheal invasion by a WDTC has a negative impact on survival, with intraluminal tumor development constituting a worse prognostic factor than superficial tracheal invasion. In WDTC, curative resection is often feasible with a small safety margin, and complete resection can ensure a good prognosis. Despite its resectability, accurate knowledge of the tracheal and peritracheal anatomy and proper selection of surgical techniques are essential for complete resection. However, there is no standard guideline on surgical indications and the recommended procedure in trachea-invading WDTC. This review discusses the indications for radical resection and the three currently available major resection methods: shaving, window resection, and sleeve resection with end-to-end anastomosis.
  • 469
  • 02 Mar 2021
Topic Review
Well-Defined
In mathematics, an expression is called well-defined or unambiguous if its definition assigns it a unique interpretation or value. Otherwise, the expression is said to be not well-defined, ill-defined or ambiguous. A function is well-defined if it gives the same result when the representation of the input is changed without changing the value of the input. For instance, if f takes real numbers as input, and if f(0.5) does not equal f(1/2) then f is not well-defined (and thus not a function). The term well-defined can also be used to indicate that a logical expression is unambiguous or uncontradictory. A function that is not well-defined is not the same as a function that is undefined. For example, if f(x) = 1/x, then the fact that f(0) is undefined does not mean that the f is not well-defined — but that 0 is simply not in the domain of f.
  • 9.2K
  • 01 Dec 2022
Topic Review
Well-Being in a Sustainable Product–Service System
To regain overall well-being in the post-pandemic era, the priorities should not be only economic growth but also human physical and mental health. 
  • 326
  • 09 Jun 2023
Topic Review
Well-Being and Elderly People in the European Union
One of the main demographic problems is the ageing of populations, especially in European countries. However, this process is not taking place equally in all countries and has a different impact on their socio-economic development.
  • 224
  • 29 Dec 2023
Topic Review
Welfare Pluralism
Under the background of an accelerating population aging process, China is facing the issues of a weakening household pension function and an insufficient social pension service supply. It is urgent to establish a perfect diversified pension service supply model. The theory of welfare pluralism advocates the participation of multiple subjects in social old-age services and emphasizes that social organizations play an important role in the provision of old-age services.
  • 2.0K
  • 13 Jun 2022
Topic Review
Welfare of Italian Heavy Pigs
Italian heavy pigs are characterized by much higher body weights and age at slaughter (approximately 160–170 kg, and over 9 months of age) than the majority of pigs reared in Europe. This results in peculiar behavioral and rearing-related needs compared to smaller pigs. However, there is a limited body of research dealing with the welfare of this productive category, and several aspects have not been investigated yet. In particular, the lack of knowledge on space requirements, injuries, and positive welfare (included human–animal relationships) are crucial aspects that should be explored in order to define a baseline to set up measures for the improvement of the production system. It is hoped that this content will help to promote knowledge and specific policies aimed at enhancing the ethical attributes of this renowned production, thus improving animal welfare, meeting consumers’ expectations, and increasing the value of its marketing chain.
  • 827
  • 05 Jul 2021
Topic Review
Welfare Indicators in Free-Roaming Horses
Animal welfare assessment is an essential tool for maintaining positive animal wellbeing. Validated welfare assessment protocols have been developed for farm, laboratory, zoo, and companion animals, including horses in managed care. However, wild and free-roaming equines have received relatively little attention, despite populations being found worldwide. In the UK, free-roaming ponies inhabit areas of Exmoor, Dartmoor, and New Forest, England, and Snowdonia National Park in Wales, amongst others. Visitors and local members of the public who encounter free-roaming ponies occasionally raise concerns about their welfare, as they are not provided with additional food, water, or shelter. In this study, we evaluated the feasibility, reliability, and repeatability of welfare indicators that can be applied to a population of free-roaming Carneddau Mountain ponies to address such concerns. Our findings indicate that many of the trialed indicators were successfully repeated and had good levels of inter-assessor reliability. Reliable and repeatable welfare indicators for free-roaming and semi free-roaming ponies will enable population managers and conservation grazing schemes to manage the welfare of free-roaming horses and ponies.
  • 522
  • 07 Jan 2022
Topic Review
Welding between Batteries and Busbars for Electric Vehicles
Electric vehicle battery systems are made up of a variety of different materials, each battery system contains hundreds of batteries. There are many parts that need to be connected in the battery system, and welding is often the most effective and reliable connection method. Laser welding has the advantages of non-contact, high energy density, accurate heat input control, and easy automation, which is considered to be the ideal choice for electric vehicle battery manufacturing. In all the production processes of power battery packs, there is a key process, that is, the welding of a single lithium battery and the connector. This is the key to the quality of series and parallel lithium-ion battery cells, that is, the welding of the battery pole and the busbars. The quality of the welding here will directly affect the reliability of the quality of the lithium-ion battery pack used as a power source for electric vehicles.
  • 505
  • 14 Aug 2023
Topic Review
Weld Pool Formation in Keyhole Plasma Arc Welding
The Keyhole Plasma Arc Welding (KPAW) process utilizes arc plasma highly constricted by a water-cooled cupper nozzle to produce great arc pressure for opening a keyhole in the weld pool, achieving full penetration to the thick plate. However, advanced control of welding is known to still be difficult due to the complexity of the process mechanism, in which thermal and dynamic interactions among the arc, keyhole, and weld pool are critically important. In KPAW, two large eddies are generally formed in the weld pool behind the keyhole by plasma shear force as the dominant driving force. These govern the heat transport process in the weld pool and have a strong influence on the weld pool formation process. The weld pool flow velocity is much faster than those of other welding processes such as Tungsten Inert Gas (TIG) welding and Gas Metal Arc (GMA) welding, enhancing the heat transport to lower the weld pool surface temperature. Since the strength and direction of this shear force strongly depend on the keyhole shape, it is possible to control the weld pool formation process by changing the keyhole shape by adjusting the torch design and operating parameters. If the lower eddy is relatively stronger, the heat transport to the bottom side increases and the penetration increases. However, burn-through is more likely to occur, and heat transport to the top side decreases, causing undercut. In order to realize further sophistication of KPAW, a deep theoretical understanding of the process mechanism is essential. 
  • 255
  • 21 Mar 2024
Topic Review
Weissenbacher-Zweymüller Syndrome
Infants born with Weissenbacher-Zweymüller syndrome are smaller than average because the bones in their arms and legs are unusually short. The thigh and upper arm bones are wider than usual at the ends (described as dumbbell-shaped), and the bones of the spine (vertebrae) may also be abnormally shaped. High-frequency hearing loss occurs in some cases. Distinctive facial features include wide-set protruding eyes, a small and upturned nose with a flat bridge, and a small lower jaw. Some affected infants are born with an opening in the roof of the mouth (a cleft palate). Most people with Weissenbacher-Zweymüller syndrome experience significant "catch-up" growth in the bones of the arms and legs during childhood. As a result, adults with this condition are not unusually short. However, affected adults still have other signs and symptoms of Weissenbacher-Zweymüller syndrome, including distinctive facial features and hearing loss.
  • 443
  • 23 Dec 2020
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