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Topic Review
Identification of New Psychoactive Substances
New (or novel) psychoactive substances (NPS) or “designer drugs”, substances that are not controlled by the 1961 Single Convention on Narcotic Drugs or the 1971 Convention on Psychotropic Substances, pose public health threats. NPS are widely available on the web, through local head shops, on streets and in schools. Many chemical and nucleic acid based methods can be used to detect and identify these substances.
  • 1.6K
  • 29 Oct 2020
Topic Review
IBM Microfilm Products
IBM manufactured and sold microfilm products from 1963 till 1969. It is an example of IBM attempting to enter an established market on the basis of a significant technical breakthrough.
  • 357
  • 24 Oct 2022
Topic Review
I-III-VI2 QDs and Derivatives for Photovoltaic Applications
I–III–VI2 group quantum dots (QDs) have attracted high attention in photoelectronic conversion applications, especially for QD-sensitized solar cells (QDSSCs). Because PV cells allow us to convert solar energy into electricity, these devices represent some of the most promising technology to meet the ever-increasing energy demand. The light-harvesting efficiency of I-III-VI2 QDs is higher than that of TiO2 due to their small bandgap and large absorption coefficient, and the use of these nanocrystals is beneficial for PV cell engineering. Upon light irradiation, electron-hole pairs are generated in I-III-VI2 QDs. When in contact with TiO2, photoexcited electrons from QDs can transfer to the CB of TiO2, and then electrons are further transferred to the external circuit (for example, fluorine-doped tin oxide, FTO). Simultaneously, holes in the VB of QDs are transported to the counter electrode (for example, Au or Pt) to complete the circuit, resulting in the flow of electricity.
  • 307
  • 07 Nov 2023
Topic Review
Hypopigmentation Mechanisms of Anti-Tyrosinase Peptides from Food Proteins
Skin hyperpigmentation resulting from excessive tyrosinase expression has long been a problem for beauty lovers, which has not yet been completely solved. Although researchers are working on finding effective tyrosinase inhibitors, most of them are restricted, due to cell mutation and cytotoxicity. Therefore, functional foods are developing rapidly for their good biocompatibility. Food-derived peptides have been proven to display excellent anti-tyrosinase activity, and the mechanisms involved mainly include inhibition of oxidation, occupation of tyrosinase’s bioactive site and regulation of related gene expression. For anti-oxidation, peptides can interrupt the oxidative reactions catalyzed by tyrosinase or activate an enzyme system, including super-oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) to scavenge free radicals that stimulate tyrosinase. In addition, researchers predict that peptides probably occupy the site of the substrate by chelating with copper ions or combining with surrounding amino acid residues, ultimately inhibiting the catalytic activity of tyrosinase.
  • 909
  • 06 May 2022
Topic Review
Hypoglycemic Effect of Resveratrol
El resveratrol (RV) es un compuesto polifenólico con propiedades antioxidantes, antiinflamatorias e hipoglucémicas. Varios estudios in vitro y en modelos animales han demostrado los efectos beneficiosos del RV; sin embargo, los resultados en humanos no son concluyentes.
  • 581
  • 25 Jan 2021
Topic Review
Hypoestrogenism
Hypoestrogenism, or estrogen deficiency, refers to a lower than normal level of estrogen. It is an umbrella term used to describe estrogen deficiency in various conditions. Estrogen deficiency is also associated with an increased risk of cardiovascular disease, and has been linked to diseases like urinary tract infections and osteoporosis. In women, low levels of estrogen may cause symptoms such as hot flashes, sleeping disturbances, decreased bone health, and changes in the genitourinary system. Hypoestrogenism is most commonly found in women who are postmenopausal, have primary ovarian insufficiency (POI), or are presenting with amenorrhea (absence of menstrual periods). Hypoestrogenism includes primarily genitourinary effects, including thinning of the vaginal tissue layers and an increase in vaginal pH. With normal levels of estrogen, the environment of the vagina is protected against inflammation, infections, and sexually transmitted infections. Hypoestrogenism can also occur in men, for instance due to hypogonadism. There are both hormonal and non-hormonal treatments to prevent the negative effects of low estrogen levels and improve quality of life.
  • 1.0K
  • 09 Nov 2022
Topic Review
Hypercrosslinking of Poly(vinylbenzyl chloride) PolyHIPEs
The concept of polymer chain hypercrosslinking was introduced by Davankov, Rogoshin and Tsyurupa, using linear polystyrene or swollen gel-type poly (styrene-co-divinylbenzene) in the presence of an external crosslinker, solvent and a Lewis base as a catalyst.
  • 757
  • 30 Aug 2021
Topic Review
Hyperchloremia
Hyperchloremia is an electrolyte disturbance in which there is an elevated level of chloride ions in the blood. The normal serum range for chloride is 96 to 106 mEq/L, therefore chloride levels at or above 110 mEq/L usually indicate kidney dysfunction as it is a regulator of chloride concentration. As of now there are no specific symptoms of hyperchloremia; however, it can be influenced by multiple abnormalities that cause a loss of electrolyte-free fluid, loss of hypotonic fluid, or increased administration of sodium chloride. These abnormalities are caused by diarrhea, vomiting, increased sodium chloride intake, renal dysfunction, diuretic use, and diabetes. Hyperchloremia should not be mistaken for hyperchloremic metabolic acidosis as hyperchloremic metabolic acidosis is characterized by two major changes: a decrease in blood pH and bicarbonate levels, as well as an increase in blood chloride levels. Instead those with hyperchloremic metabolic acidosis are usually predisposed to hyperchloremia. Hyperchloremia prevalence in hospital settings has been researched in the medical field since one of the major sources of treatment at hospitals is administering saline solution. Previously, animal models with elevated chloride have displayed more inflammation markers, changes in blood pressure, increased renal vasoconstriction, and less renal blood flow as well at glomerulus filtration, all of which are prompting researchers to investigate if these changes or others may exist in patients. Some studies have reported a possible relationship between increased chloride levels and death or acute kidney injury in severely ill patients that may frequent the hospital or have prolonged visits. There are other studies that have found no relationship. As studies continue, it is important to include a large patient sample size, a diverse patient population, and a diverse range of hospitals involved in these studies.
  • 722
  • 11 Oct 2022
Topic Review
Hydroxyapatite Nanoparticles in Drug Delivery
A biomaterial is a synthetic material used to replace part of a living system or a material meant to be in contact with living tissue. In this sense, biomaterials can be categorized into polymers, liposomes, micelles, dendrimers, and calcium phosphate (CaP) nanoparticles, where each will show a different type of bioactivity. Hydroxyapatite (HAP) has been the gold standard in the biomedical field due to its composition and similarity to human bone. HAP nanoparticles have been used as vehicles for delivery due to their affinity to DNA, proteins, several drugs, and proper release activity.
  • 893
  • 02 Nov 2021
Topic Review
Hydroxyapatite Nanoparticles
Hydroxyapatite nanoparticles (HAP-NP) are incorporated in oral care products such as toothpastes and mouthwashes to treat dental sensitivity or to promote enamel remineralisation. Despite the good performance of HAP-NP in this application, it is important to ensure its safety for consumers. For that reason, the Scientific Committee on Consumer Safety (SCCS) evaluated the safety of HAP-NP as an oral care ingredient, but the issued opinion was not completely conclusive and the SCCS recommended that additional tests should be performed. The aim of the present study was to assess biocompatibility of a specific commercial HAP-NP to clarify the safety of this ingredient for oral care applications. Results evidence the safety of this HAP-NP for oral care products with the use of an in vitro replacement alternative for human gingival epithelium and a simulated gastric fluid assay.
  • 2.4K
  • 01 Nov 2020
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