Everything below concerns LC-MS. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-09-25. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
The peer-reviewed record is dominated by small early-phase studies, case reports and pharmacovigilance summaries rather than large randomised trials. Papers typically examine tanning response, receptor selectivity or patterns of reported adverse events. Many note that participants obtained the peptide outside a clinical setting, which limits verification of composition and administered amount. Reported events vary widely, and causality is frequently unclear because the identity and purity of self-sourced material are unknown. Open questions include whether repeated melanocortin receptor stimulation produces cumulative effects, and how often label claims match actual content.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
As of 2016, NASA has published over 2,000 other spin-offs in the fields of computer technology, environment and agriculture, health and medicine, public safety, transportation, recreation, and industrial productivity. Contrary to common belief, NASA did not invent Tang, Velcro or Teflon.
UV can be used to pasteurize fruit juices by flowing the juice over a high-intensity ultraviolet source. The effectiveness of such a process depends on the UV absorbance of the juice. Pulsed light (PL) is a technique of killing microorganisms on surfaces using pulses of an intense broad spectrum, rich in UVC between 200 and 280 nm. Pulsed light works with xenon flash lamps that can produce flashes several times per second. Disinfection robots use pulsed UV. The antimicrobial effectiveness of filtered far-UVC (222 nm) light on a range of pathogens, including bacteria and fungi showed inhibition of pathogen growth, and since it has lesser harmful effects, it provides essential insights for reliable disinfection in healthcare settings, such as hospitals and long-term care homes. UVC has also been shown to be effective at degrading SARS-CoV-2 virus.
== Reactions == Fraser stated in July 2023 that over five hundred athletes had contacted him asking for more information. In August, D'Souza said that he had 500 "sleeper athletes" who are "breaking world records in their basement and sending us videos of it" ready for competition. In February 2024, he said that thousands of athletes interested in participating had contacted him. CNN reported in October 2023 that no athletes had publicly committed to the event; however, by early 2026, several high-profile international competitors, including former world champion James Magnussen and British swimmer Emily Barclay, had expressed interest or confirmed their participation.
Sources: en.wikipedia.org
=== Chirality === The carbon atom next to the carboxyl group is called the α–carbon. In proteinogenic amino acids, it bears the amine and the R group or side chain specific to each amino acid, as well as a hydrogen atom. With the exception of glycine, for which the side chain is also a hydrogen atom, the α–carbon is stereogenic. All chiral proteinogenic amino acids have the L configuration, and can therefore be referred to as L-amino acids. They are "left-handed" enantiomers, which refers to the stereoisomers of the alpha carbon. A few D-amino acids ("right-handed") have been found in nature, e.g., in bacterial envelopes, as a neuromodulator (D-serine), and in some antibiotics. Rarely, D-amino acid residues are found in proteins, and are converted from the L-amino acid as a post-translational modification.
In contrast to mirtazapine, the selective serotonin reuptake inhibitors, serotonin–norepinephrine reuptake inhibitors, monoamine oxidase inhibitors, and some tricyclic antidepressants acutely increase the general activity of the 5-HT2A, 5-HT2C, and 5-HT3 receptors, leading to a number of negative changes and side effects, the most prominent of which include anorexia, insomnia, nausea, and diarrhea, among others. However, most of these adverse effects are temporary, since down regulation of 5-HT2A receptors eventually occurs following chronic SSRI treatment, and desensitization of 5-HT3 receptors often occurs within a week or less. This is precisely why SSRIs have a delayed antidepressant and anxiolytic effect, and occasionally, an acute anxiogenic effect before down regulation occurs. Mirtazapine, on the other hand, is an antagonist of the 5-HT2A receptor, and antagonists at this receptor typically induce reverse tolerance. Thus, the antidepressant and anxiolytic effects of mirtazapine occur more rapidly than with SSRIs. Furthermore, its reduced incidence of sexual dysfunction (such as loss of libido and anorgasmia) could be a product of negligible binding to the serotonin transporter and antagonism of the 5-HT2A receptors; however, Mirtazapine's high affinity towards and inverse agonism of the 5-HT2C receptors may greatly attenuate those pro-sexual factors (as evidenced by the pro-sexual effects of drugs like m-CPP and lorcaserin which agonize 5-HT2C receptors in a reasonably selective manner).
Technetium (99mTc) pentetic acid, sold under the brand name Draximage DTPA among others, is a radiopharmaceutical medication used in nuclear medicine to image the brain, kidneys, or lungs. It is given by intravenous injection or via aerosol spray. It consists of technetium-99m bound to the conjugate base of pentetic acid, with sodium as an additional cation.
Sources: en.wikipedia.org
=== Stress-responsive kinases === Kinases that regulate p53 phosphorylation can be divided into two broad groups. One group includes members of the MAPK pathways, including JNK1–3, ERK1/2 and p38 MAPK, which are activated by diverse cellular stresses such as oxidative stress and heat shock. A second group comprises DNA damage response kinases, including ATM, ATR and DNA-PK, together with downstream checkpoint kinases such as CHK1 and CHK2, which are activated by DNA damage and replication stress and contribute to p53 regulation through phosphorylation-dependent signalling. Additional kinases implicated in p53 phosphorylation include the CDK-activating kinase (CAK; CDK7–cyclin H–MAT1), which has been shown to phosphorylate p53 (for example at Ser33) in vitro and in vivo, and TP53RK (PRPK), which has been reported to phosphorylate p53 at Ser15. Oncogene-induced activation of p53 can also occur via p14ARF (ARF), which inhibits the p53 antagonist MDM2 and thereby stabilizes p53.
Korsmeyer Award, ASCI (2008) Distinguished Leader in Insulin Resistance Award (2008) Elected Fellow, American Association for the Advancement of Science (2009) Outstanding Clinical Investigator Award, Endocrine Society (2012) Sir Philip Randle Award, Biochemical Society (2013) Elected to Master, American Association of Clinical Endocrinology (2015) Solomon Berson Award, American Physiological Society (2016) Harrington Scholar-Innovator (2016) Inaugural Fellow, American Physiological Society (2016) Distinguished Alumni Award, Wayne State University (2016) Banting Medal for Lifetime Scientific Achievement, American Diabetes Association (2018) Elected to the American Academy of Arts and Sciences (2018) Arthur Riggs Award, City of Hope (2019) Stanley Mirsky Award, Icahn School of Medicine at Mount Sinai (2019) Samuel Eichold II Memorial Award, American College of Physicians (2020) Manpei Suzuki International Prize for Diabetes Research (2021) Elected to Master, American College of Physicians (2021) Fellow of the Royal College of Physicians (2021) EASD-Lilly Centennial Anniversary Prize for Landmark Discoveries in Diabetes, European Association for the Study of Diabetes (2023) Bodil Schmidt-Nielsen Distinguished Mentor and Scientist Award, American Physiological Society (2024) EASD-Novo Nordisk Foundation Diabetes Prize for Excellence (2025)
Charnia fossils were originally found in the Charnwood Forest in England, hence named Charnia. These fossils are from marine organisms that lived on the bottom of the ocean floor. The fossils have a fractal body plan and were frond shaped, meaning they resembled broad-leafed plants such as ferns. However they could not have been plants since they resided in the dark depths of the ocean floor. In Charnwood Forest, Charnia was found as an isolated species, however there were many more fossils found on the East Coast of Canada in Mistaken Point in Newfoundland. Charnia was attached to the bottom of the ocean floor, and was strongly current aligned. This is seen because there are disk-like shapes at the bottom of the Charnia fossil, which show where Charnia was tethered, and all the nearby fossils are facing the same direction. These fossils at Mistaken Point were preserved well under volcanic ash and layers of soft mud. It has been determined via radiometric dating of the fossils that Charnia must have lived around 565 million years ago.
=== Neurosurgical repair === Surgery to treat a CSF-venous fistula in CSF leak patients is highly effective. Neurosurgery is available to directly repair leaking meningeal diverticula. The areas of dura leak can be tied together in a process called ligation and then a metal clip can be placed in order to hold the ligation closed. Alternatively, a small compress called a pledget can be placed over the dura leak and then sealed with gel foam and fibrin glue. Primary suturing is rarely able to repair a CSF leak, and in some patients exploration of the dura may be required to properly locate all sites of CSF leak.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.