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Topic Review
Osteoclasts and Osteoblasts
The bone is a complex organ that is dependent on a tight regulation between bone formation by osteoblasts (OBs) and bone resorption by osteoclasts (OCs). The OC is a multinucleated giant cell, arising from the fusion of many mononuclear OC precursors with a myeloid/monocyte origin. Differently from OCs, OBs arise from pluripotent mesenchymal stem cells (MSCs). The main function of OBs is the synthesis of new bone matrix. Bone metabolism is regulated by various hormones or cytokines and dysregulation in this complex system can lead to numerous diseases characterized either by enhanced bone resorption (osteoporotic phenotype) or enhanced bone formation (osteopetrotic phenotype).
  • 1.9K
  • 09 May 2021
Topic Review
DPSCs in Regenerative Therapy
Recently, dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs) have attracted substantial attention as promising cell sources for tissue regeneration. Here, we summarized the features of DPSCs and SHEDs such as high growth capacity, multipotency, expression of cell markers, immunomodulatory effects, and their potential to regenerate various somatic tissues.  Mesenchymal stem cells (MSCs) have the capacity for self-renewal and multilineage differentiation potential, and are considered a promising cell population for cell-based therapy and tissue regeneration. MSCs are isolated from various organs including dental pulp, which originates from cranial neural crest-derived ectomesenchyme. Recently, dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs) have been isolated from dental pulp tissue of adult permanent teeth and deciduous teeth, respectively. Because of their MSC-like characteristics such as high growth capacity, multipotency, expression of MSC-related markers, and immunomodulatory effects, they are suggested to be an important cell source for tissue regeneration.
  • 1.9K
  • 09 Nov 2020
Topic Review
Sample Preparation for Cosmetics Analysis
Traditional cosmetics sample preparation techniques involve liquid–liquid extraction (LLE) and solid–liquid extraction (SLE). In last years, modern sample extraction techniques are advancing towards fast sample processing, easy automatization, as well as a reduction in organic solvent volumes, in agreement with the green chemistry principles in two ways (i) the miniaturization of conventional procedures allowing a reduction of the solvents and reagents consumption and (ii) the development and application of sorbent- and liquid-based microextraction technologies to obtain a high analyte enrichment, avoiding or significantly reducing the use of organic solvents.
  • 1.9K
  • 24 Nov 2021
Topic Review
Ionising Radiation Sensors
Ionising radiation affects electronic circuits as well as living beings and has been a major concern for various critical applications such as healthcare, mining, avionics, nuclear, high-energy physics, and space applications. Radiation sensors are essential tools to estimate, measure and characterise radiation related information to assess the system performance and subsequently look for corrective measures. 
  • 1.9K
  • 23 Sep 2021
Topic Review
Cable-Supported Grid Structures
The cable-supported grid structure (CSGS) is a hybrid structure combined with rigidity and flexibility. Its formed state is closely related to the zero-stress state, construction process, and prestress distribution. 
  • 1.9K
  • 15 Jun 2022
Topic Review
Oneirology
Oneirology (/ɒnɪˈrɒlədʒi/; from Greek ὄνειρον, oneiron, "dream"; and -λογία, -logia, "the study of") is the scientific study of dreams. Current research seeks correlations between dreaming and current knowledge about the functions of the brain, as well as understanding of how the brain works during dreaming as pertains to memory formation and mental disorders. The study of oneirology can be distinguished from dream interpretation in that the aim is to quantitatively study the process of dreams instead of analyzing the meaning behind them.
  • 1.9K
  • 14 Oct 2022
Topic Review
Proper Name
In the philosophy of language, a proper name – examples include a name of a specific person or place – is a name which ordinarily is taken to uniquely identify its referent in the world. As such it presents particular challenges for theories of meaning, and it has become a central problem in analytic philosophy. The common-sense view was originally formulated by John Stuart Mill in A System of Logic (1843), where he defines it as "a word that answers the purpose of showing what thing it is that we are talking about but not of telling anything about it". This view was criticized when philosophers applied principles of formal logic to linguistic propositions. Gottlob Frege pointed out that proper names may apply to imaginary and nonexistent entities, without becoming meaningless, and he showed that sometimes more than one proper name may identify the same entity without having the same sense, so that the phrase "Homer believed the morning star was the evening star" could be meaningful and not tautological in spite of the fact that the morning star and the evening star identifies the same referent. This example became known as Frege's puzzle and is a central issue in the theory of proper names. Bertrand Russell was the first to propose a descriptivist theory of names, which held that a proper name refers not to a referent, but to a set of true propositions that uniquely describe a referent – for example, "Aristotle" refers to "the teacher of Alexander the Great". Rejecting descriptivism, Saul Kripke and Keith Donnellan instead advanced causal-historical theories of reference, which hold that names come to be associated with individual referents because social groups who link the name to its reference in a naming event (e.g. a baptism), which henceforth fixes the value of the name to the specific referent within that community. Today a direct reference theory is common, which holds that proper names refer to their referents without attributing any additional information, connotative or of sense, about them.
  • 1.9K
  • 21 Oct 2022
Topic Review
Rikhter R-23
The Rikhter R-23 is an aircraft autocannon developed for the Soviet Air Force starting in the late 1950s. It was designed to be as short as possible to avoid problems found on high-speed aircraft when the guns were pointed into the airstream. The R-23 was a gas operated revolver cannon that used gas bled from holes in the barrel to provide the motive force. Firing up to 2,600 rpm, the R-23 was the fastest firing single-barrel cannon ever introduced into service. The R-23 took some time to develop, and was not used operationally until 1964. It was used only in the tail turret of the Tu-22, and experimentally on the Salyut 3 space station. Its role was taken over by the twin-barrel Gryazev-Shipunov GSh-23. A modified version of the weapon was the only cannon to have been fired in space.
  • 1.9K
  • 08 Nov 2022
Topic Review
Keloid
Keloid, also known as keloid disorder and keloidal scar, is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1. Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to the color of the person's skin or red to dark brown in color. A keloid scar is benign and not contagious, but sometimes accompanied by severe itchiness, pain, and changes in texture. In severe cases, it can affect movement of skin. Worldwide, men and women of African, Asian, Hispanic and European descent can develop these raised scars. In the United States keloid scars are seen 15 times more frequently in people of sub-Saharan African descent than in people of European descent. There is a higher tendency to develop a keloid among those with a family history of keloids and people between the ages of 10 and 30 years. Keloids should not be confused with hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound.
  • 1.9K
  • 18 Nov 2022
Topic Review
Wearable Point-of-Care Devices
Personalized point-of-care testing (POCT) devices, such as wearable sensors, enable quick access to health monitoring without the use of complex instruments. Wearable sensors are gaining popularity owing to their ability to offer regular and continuous monitoring of physiological data by dynamic, non-invasive assessments of biomarkers in biofluids such as tear, sweat, interstitial fluid and saliva. 
  • 1.9K
  • 09 May 2023
Topic Review
Mathematics Enrichment Program
The mathematics enrichment activities aim to provide students with a stimulating mathematical experience, promote positive attitudes, raise the level of achievement, and contribute to efforts to enhance, generalize, and increase the general understanding of mathematics.
  • 1.9K
  • 26 Jan 2024
Topic Review
EU Road Transport Carbon Emissions
To accomplish the 1.5 °C and 2 °C climate change targets, the European Union (EU) has set up several policy initiatives. Within the EU, the carbon emissions of the road transport sector from the consumption of diesel and gasoline are constantly rising. (1) Background: due to road transport policies, diesel and gasoline use within the EU is increasing the amount of carbon in the atmosphere and adding to climate risks. (2) Methods: sustainability analysis used was based on the method recommended by the Intergovernmental Panel on Climate Change. (3) Results: to meet its road transport requirements, the EU produces an estimated 0.237–0.245 billion tonnes of carbon per year from its total consumption of diesel and gasoline. (4) Conclusion: if there is no significant reduction in diesel and gasoline carbon emissions, there is a real risk that the EU’s carbon budget commitment could lapse and that climate change targets will not be met. Sustainability analysis of energy consumption in road transport sector shows the optimum solution is the direct electrification of road transport. 
  • 1.9K
  • 20 Aug 2021
Topic Review
Development Environments and Factors of Subsidence Dolines
On covered karsts, the frequent and rapid development of subsidence dolines result in the striking change of surface conditions and this process may cause a significant damage to man-made constructions. According to current scientific knowledge, a prediction on the development of subsidence dolines and their development sites, by which the damage could be reduced to a great extent, is not possible yet. Based on literary data, in this study, development environments and impacts are described that affect subsidence doline development and the site of development. Point of views are suggested for predicting the development and development sites.
  • 1.9K
  • 11 Jan 2022
Topic Review
The Impact of Endocrine-Disrupting Chemicals in Male Fertility
Any compound or mixture of compounds, which interferes with any aspect of the endocrine system is classified as an endocrine-disrupting chemical (EDC). There is increasing evidence that male infertility is associated with the widespread exposure to EDCs, and in particular to obesogens. These compounds interfere with hormones involved in the regulation of metabolism and are associated with weight gain, being also able to change the functioning of the male reproductive axis and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. The permanent exposure to obesogens has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline of male fertility and key players in shaping the future health outcomes not only for those who are directly exposed but also for upcoming generations. In addition to the changes that lead to inefficient functioning of the male gametes, obesogens induce alterations that are “imprinted” on the genes of the male gametes, establishing a link between generations and contributing to the transmission of defects.
  • 1.9K
  • 29 Mar 2022
Topic Review
Commercial Antimicrobial Wound Dressings Based on Polyhexanide-Releasing Membranes
The prevalence of chronic, non-healing skin wounds in the general population, most notably diabetic foot ulcers, venous leg ulcers and pressure ulcers, is approximately 2% and is expected to increase, driven mostly by the aging population and the steady rise in obesity and diabetes. Non-healing wounds often become infected, increasing the risk of life-threatening complications, which poses a significant socioeconomic burden. Aiming at an improved management of infected wounds, a variety of wound dressings that release the antiseptic polyhexanide (poly(hexamethylene biguanide); PHMB), has been introduced in the wound-care market. An overview of the main characteristics and applications of PHMB and of the main fabrication methods and characteristics of commercial PHMB-releasing wound dressings is presented.
  • 1.9K
  • 05 Jan 2023
Topic Review
Industry 4.0 in Africa
The fourth industrial revolution presents an upspring opportunity for the African continent to adopt technologies such as artificial intelligence, big data, internet-enabled industrial platforms, 3D printing, robotics, nanotechnology, and blockchains. This is more so because the past three industrial revolutions saw the African continent being left out of its opportunities despite its affluent population and natural resources. Africa stands to benefit from industrial development, digitalization, and greater integration, which would result in more excellent opportunities for the growing youthful populations.
  • 1.9K
  • 18 Jan 2023
Topic Review
Diffusion Weighted Imaging in Neuro-Oncology
Diffusion weighted imaging (DWI) is an imaging technique commonly used for the assessment of acute ischemia, inflammatory disorders, and CNS neoplasia. It has several benefits since it is a quick, easily replicable sequence that is widely used on many standard scanners. In addition to its normal clinical purpose, DWI offers crucial functional and physiological information regarding brain neoplasia and the surrounding milieu.
  • 1.9K
  • 24 Apr 2023
Topic Review
The Mechanisms for Bone Regeneration
The bone regeneration process has historically been studied with the repair of fracture as a unique ability of our body by restoring it to its pre-injured functions. In bone biology, homeostasis is regulated by two main cellular components: osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells). Furthermore, various inflammatory cells and cytokines dynamically interact with these cells in bone environments, which are responsible for their repair capacity. For the bone regeneration process, previous studies have emphasized the role of osteoblasts with morphogen gradients such as bone morphogenetic proteins (BMPs).
  • 1.9K
  • 19 Dec 2023
Topic Review
Distributed Propulsion for Next-Generation Aircraft
Developments in the design of transport aircraft are increasingly focusing on the search for innovative solutions to improve general performance and reduce the environmental impact of flight operations. In this context, specific attention is being devoted to research into non-conventional solutions for the integration of the propulsion system, involving two different interconnected technological threads. From a general point of view, new types of propulsion systems are under investigation, and technologies involving new fuels, such as hydrogen or sustainable aviation fuels, or electric and hybrid-electric powertrains, are under development to provide breakthrough forward advancements in the field. In addition to these important innovations, and in a way that is generally complementary, non-conventional powertrain/airframe integrations are increasingly being investigated since, either as standalone or in combination with previous new power supply concepts, they can contribute to general improvements in aircraft performance, with significant implications for reducing environmental impact. Among the advanced technologies under investigation, it is worth mentioning distributed propulsion, which is gaining much interest, especially in the context of synergistic integration with electric powertrains.
  • 1.9K
  • 01 Mar 2024
Topic Review
Health Risks of Children in Marathon Races
Compared with other sports, running is popular sport for children throughout the world. Over the last few decades, marathon running has become increasingly popular even in the age group below 18 years. While the majority of youth athletes fall within the 16–18 age range, it is noteworthy that there are also participants younger than 12 years engaging in marathon races. Advice on the safety of youth athletes participating in these events is frequently sought by parents, coaches, sport scientists, and medical professionals, particularly concerning potential short- and long-term health consequences. The act of marathon running has the potential to impact key organ systems during the crucial phases of growth and development. To ensure the safety of marathon running in youth runners, it is essential to address multiple physiological and psychological aspects of health. These recommendations are directed towards ensuring the safe participation of youth athletes in marathon races through proper and individualized assessments.
  • 1.9K
  • 02 Apr 2024
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