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Topic Review
Tyrocidine
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Bacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation. Tyrocidines A, B, and C are cyclic decapeptides. The biosynthesis of tyrocidine involves three enzymes. Parts of its sequence are identical to gramicidin S.
  • 1.2K
  • 15 Nov 2022
Topic Review
Tractatus Logico-Philosophicus (6.5)
In the Tractatus Logico-Philosophicus of Ludwig Wittgenstein, Proposition 6.5 seeks to ground his philosophy of action (Proposition 7: "Whereof one cannot speak, thereof one must be silent"). Although the historical significance of Tractatus is for its influence on the philosophers of logical empiricism, by providing them with a framework for a philosophy of science, and hence engineering, Wittgenstein actually wrote it as a work on ethics. See his propositions 6.4 onward. But his motivation for writing, and the style of presentation, follow Frege and Russell, below.
  • 1.2K
  • 18 Nov 2022
Topic Review
Chemical Compositions and Biosynthesis of Black Goji Anthocyanins
Lycium ruthenicum is a therapeutic plant and its fruits (black goji) are commonly used as a traditional Chinese medicine. Among the 39 identified black goji anthocyanins (BGAs), most are 3,5-diglycoside derivatives of petunidin (>95%) with an individual anthocyanin [petunidin 3-O-rutinoside (trans-p-coumaroyl)-5-O-glucoside], accounting for 80% of the total BGAs. Due to their unique anthocyanin profile, BGAs possess various health benefits.
  • 1.2K
  • 23 Nov 2022
Topic Review
Assessing the Role of Water Resources Protection Globally
Water resource protection is central to sustainable water supply management for human wellbeing and for the ecological ecosystem to flourish. Water resources protection plays a critical role in policy practice to mitigate water resources challenges and in mitigating social wellbeing. Such practice is central to sustainable water supply management for human wellbeing and for the ecological ecosystem to flourish. Appropriate implementation and monitoring of water resources protection practice has received much attention on the international agenda. Approaches such as results-oriented policy monitoring are seen as appropriate methodologies for monitoring policy implementation practice to assess policy impacts.
  • 1.2K
  • 20 Jan 2023
Topic Review
Adverse Side Effects of Long-Term Lithium Therapy
Lithium remains the drug of first choice for prophylactic treatment of bipolar disorder, preventing the recurrences of manic and depressive episodes. The longitudinal experiences with lithium administration greatly exceed those with other mood stabilizers. Among the adverse side effects of lithium, renal, gastrointestinal, neurological, thyroid, metabolic, cognitive, dermatological, cardiologic, and sexual are listed. Probably, the most important negative effect of lithium, occurring mostly after 10–20 years of its administration, is interstitial nephropathy.
  • 1.2K
  • 06 Feb 2023
Topic Review
Achievement Goal Orientation and Academic Engagement
Enhancing academic engagement in university students can help enrich students’ educational experience. Drawing on the Conservation of Resources Model and the Job Demand-Resources Model, exploring the links between undergraduates’ achievement goal orientation and academic engagement (AE), by examining the mediating functions of perceived school climate (PSC) and academic self-efficacy (ASE).
  • 1.2K
  • 20 Mar 2023
Topic Review
Design Improvements of DC Circuit Breaker
While traditional AC mechanical circuit breakers can protect AC circuits, many other DC power distribution technologies, such as DC microgrids (MGs), yield superior disruption performance, e.g., faster and more reliable switching speeds. However, novel DC circuit breaker (DCCB) designs are challenging due to the need to quickly break high currents within milliseconds, caused by the high fault current rise in DC grids compared to AC grids. In DC grids, the circuit breaker must not provide any current crossing and must absorb surges, since the arc is not naturally extinguished by the system. Additionally, the DC breaker must mitigate the magnetic energy stored in the system inductance and withstand residual overvoltages after current interruption. These challenges require a fundamentally different topology for DCCBs, which are typically made using solid-state semiconductor technology, metal oxide varistors (MOVs), and ultra-fast switches.
  • 1.2K
  • 06 Sep 2023
Topic Review
Cenancestor
Cenancestor, the last universal cellular ancestor (LUCA), is assumed to exist on the basis of extensive sharing of inferred homologous characters among representatives of living cellular organisms. These characteristics include the nearly universal genetic code, the concordance of phylogenetic trees from different genes, the sharing of fundamental biochemical processes, and numerous transitional fossils. A cenancestor would be a logical necessity if the cellular structure originated only once, given the cell theory stating that new cells are created by old cells dividing into two. The recent empirical search for the cenancestor started with the prediction that eukaryotes could not possibly have evolved from the common ancestor of extant bacterial species. This led to the discovery of Archaebacteria and the three domains of life. Archaebacteria was found to be "archae" only to eukaryotes and consequently renamed to Archaea. The molecular substantiation of the endosymbiotic hypothesis of mitochondrial and chloroplast origin led to the hypothesis that the nucleus in eukaryotes is also an organelle originating from endosymbiosis or cell fusion, followed by massive horizontal gene transfer (HGT) between an engulfing host and engulfed guests which serve as mitochondrial and chloroplast progenitors. The cenancestor is expected to coexist with a variety of viruses that may mediate HGT to bring heterogeneous genomes together. This virus-mediated and plasmid-mediated genomic assembly and exchange could abolish one major difficulty in creating endosymbiotic genomes, i.e., the need for primitive cells to engulf each other – a difficult feat if they had cell walls.
  • 1.2K
  • 07 Dec 2024
Topic Review
Inherently Antimicrobial Nano-Systems
Inherently antimicrobial properties have been established for a number of materials, including silver, copper, and certain polymers, such as chitosan. Nanomaterials made of these inherently antimicrobial materials have attracted attention for combatting AMR because bacterial resistance to these materials is rare. However, many inherently antimicrobial nanomaterials can be cytotoxic, so they are often combined with other materials in hybrid nano-systems to increase their biocompatibility. These inherently antimicrobial nano-systems have many practical applications.
  • 1.2K
  • 20 Sep 2023
Topic Review
Business Leadership and Corporate Social Responsibility
The COVID-19 pandemic is without question posing a generation-defining challenge for public health and the global economy. Moreover, the pandemic has revived some old and introduced many new threats that today’s business leaders will have to face in the years to come. Despite the fact that the COVID-19 crisis was a humanitarian tragedy that continues to ravage millions of lives, it can also be viewed as an excellent opportunity to restart sustainable economic development as well as to help our business and economy to shift towards real business corporate social responsibility and ethical decision-making (thanks to the reduction in carbon emissions as a result of reduced economic activity and travel, increasing investments into healthcare and education, or finding the new ways for working and learning, such as remote work and online education).
  • 1.2K
  • 11 Dec 2023
Topic Review Peer Reviewed
A Review of Event-Based Conceptual Rainfall-Runoff Models: A Case for Australia
Event-based models focus on modelling of peak runoff from rainfall data. Conceptual models indicate simplified models that provide reasonably accurate answers despite their crude nature. Rainfall-runoff models are used to transform a rainfall event into a runoff event. This paper focuses on reviewing computational simulation of rainfall-runoff processes over a catchment. Lumped conceptual, event-based rainfall-runoff models have remained the dominant practice for design flood estimation in Australia for many years due to their simplicity, flexibility, and accuracy under certain conditions. Attempts to establish regionalization methods for prediction of design flood hydrographs in ungauged catchments have seen little success. Therefore, as well as reviewing key rainfall-runoff model components for design flood estimation with a special focus on event-based conceptual models, this paper covers the aspects of regionalization to promote their applications to ungauged catchments.
  • 1.2K
  • 13 Jun 2024
Topic Review
Requirement Quality Assessment Method Based on User Stories
Agile development processes based on user stories often face issues such as incomplete, inconsistent, and inaccurate user requirements, which increase the workload of agile development teams and reduce the efficiency of product function development, ultimately resulting in the inability to respond quickly to user requirements.
  • 1.2K
  • 25 May 2023
Topic Review
Metabolic Engineering of Wine Strain
The adaptive laboratory evolution (ALE) is a technique of strain optimization that assumes serial or continuous culturing of a particular yeast strain for many generations under selective pressure, such as high ethanol content, high osmolarity etc., thus directing the accumulation of mutants with desired phenotype. As compared to stochastic and laborious CSI techniques, ALE methods are more targeted and convenient . The power of this approach towards optimizing wine yeast is exemplified by generation of strains with altered production of important metabolites (ethanol, glycerol, succinic, and acetic acid) and more rapid sugar utilization, strains with increased sulfite tolerance and glycerol accumulation, strains with improved resistance towards KCL-induced osmotic stress with increased glycerol and reduced ethanol content, as well as enhanced viability and resveratrol production.
  • 1.2K
  • 03 Nov 2020
Topic Review
Secretome Proteomic Approaches
Searching for new cancer-related biomarkers is a key priority for the early detection of solid tumors, such as colorectal cancer (CRC), in clinically relevant biological fluids. The cell line and/or tumor tissue secretome represents a valuable resource for discovering novel protein markers secreted by cancer cells. The advantage of a secretome analysis is the reduction of the large dynamic range characterizing human plasma/serum, and the simultaneous enrichment of low abundance cancer-secreted proteins, thereby overcoming the technical limitations underlying the direct search in blood samples.
  • 1.2K
  • 11 Sep 2020
Topic Review
EVs, Substance Abuse, and HIV
While extracellular vesicles (EVs) have been shown to play a role in CNS disorders, the intersection of EVs, drug use, and HIV is of particular interest. The interactions of HIV and drugs of abuse are a growing concern given the increasing incidence of HIV transmission via shared needles in illicit drug use. As a drug commonly taken through shared needles, METH is being investigated due to its role in exacerbating HIV-mediated inflammation through both increased vesicular shedding and extracellular release. In vivo experiments have shown that cocaine-induced EV release impacts synaptic plasticity through noncoding RNA. Nicotine studies have also highlighted how the differential packaging of antioxidant enzyme cargoes into EVs affects nicotine-mediated HIV pathogenesis. Additionally, studies of both morphine and heroin have demonstrated differences in the miRNA cargoes of EVs, potentially impacting gene expression and exacerbating HIV. Studies of alcohol use in combination with HIV have shown that EV cargoes such as cytokines are affected in HIV-infected subjects who use alcohol. Investigating EV cargo alterations in all forms of substance abuse studies may allow the EV, HIV, and addiction fields to progress towards diagnosis and remedies for substance-abuse-induced toxicity in HIV patients.
  • 1.2K
  • 27 Sep 2020
Topic Review
Episodic Memory Performance
The aim of this entry was to investigate whether oxygen is a rate limiting factor for any of the main cognitive domains in healthy young individuals. Subjects were randomly assigned to either increased oxygen supply using hyperbaric oxygen (two atmospheres of 100% oxygen) or to a “sham” treatment (simulation of increased pressure in the chamber breathing normal air). While in the chamber, participants went through a battery of tests evaluating the major cognitive domains including information processing speed, episodic memory, working memory, cognitive flexibility, and attention. The results demonstrated that from all evaluated cognitive domains, a statistically significant improvement was found in the episodic memory of the hyper-oxygenized group. The hyper-oxygenized group demonstrated a better learning curve and a higher resilience to interference. The results of this study indicate that memory function is a continuum that does not reach its maximal ceiling effect at the normal sea level environment even in healthy young individuals. Understanding the biological limitation of our cognitive functions is important for future development of interventional tools that can be used in the daily clinical practice.
  • 1.2K
  • 30 Sep 2021
Topic Review
NRAS Gene
NRAS proto-oncogene, GTPase
  • 1.2K
  • 24 Dec 2020
Topic Review
Mismatch Repair Deficiency
Universal MMR/MSI testing is standard of care for all patients with newly diagnosed CRC based on multi-society guidelines in the United States. Such testing is intended to identify patients with Lynch Syndrome due to a germline mutation in an MMR gene, but also detects those with sporadic dMMR/MSI-high CRCs.
  • 1.2K
  • 19 Feb 2021
Topic Review
Mini/Micro/Nano Scale Liquid Metal Motors
Swimming motors navigating in complex fluidic environments have received tremendous attention over the last decade. In particular, liquid metal (LM) as a new emerging material has shown considerable potential in furthering the development of swimming motors, due to their unique features such as fluidity, softness, reconfigurability, stimuli responsiveness, and good biocompatibility. LM motors can not only achieve directional motion but also deformation due to their liquid nature, thus providing new and unique capabilities to the field of swimming motors. 
  • 1.2K
  • 28 Apr 2021
Topic Review
Cholinesterase Modeling and Simulation
The cholinesterase enzyme family has but two members: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE).  Computational efforts to better understand these enzymes, with a focus on their structural and catalytic properties and dynamics, includes docking and other Monte Carlo based calculations, as well as dynamic simulations of varying rigor and resource-demand including molecular dynamics, Langevin dynamics, quantum mechanical/molecular mechanics, and related algorithms. 
  • 1.2K
  • 21 Apr 2021
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