g.tanaka
TL3 Regular · Nagoya, JP
Materials scientist. Adsorption to surfaces, container closure, and why concentration matters for losses.
Joined 22 October 2024 · last posted 3d · groups: analytical-chemists
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[2026 update] Detection wavelength and why 214 nm and 280 nm disagree Replied, post #69 · Analytics › HPLC & UHPLC · 25 Jul 2026 · 4 likes Area percent is not mass percent. It is a proportion of absorbance, weighted by each species' extinction coefficient. For closely related impurities the approximation…
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Revisiting: The best-written scientific paper you have read Replied, post #115 · Lounge › Off topic · 25 Jul 2026 · 10 likes Adjacent and interesting: you might post something about nutrition, bioavailability from a food perspective, or the sociology of weight. Adjacent to this community's…
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Coming back to: Preparing for an appointment: one page, three questions Replied, post #10 · Clinical › Prescriber conversations · 17 Jul 2026 · 0 likes What to bring: copies of relevant lab results, pharmacy records (to confirm doses actually taken), and records of any adverse effects you have experienced with other…
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Why the Start Here categories exist, and what they are not for Replied, post #8 · Start Here › Welcome · 17 Jul 2026 · 0 likes Nothing here requires expertise. The experienced members here got that way by posting questions, not by knowing the answer before they showed up. If you know something…
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What is genuinely unknown about long-term amylin agonism Replied, post #44 · Compounds › Cagrilintide & amylin analogues · 16 Jul 2026 · 0 likes Gastric emptying: both amylin and GLP-1 slow it, through partly overlapping but distinct mechanisms. Whether the slowing at a higher magnitude produces disproportionate…
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Coming back to: Time to steady state after a dose increase Replied, post #102 · Pharmacology › Pharmacokinetics · 16 Jul 2026 · 0 likes Albumin binding: semaglutide binds albumin through a fatty side chain, which sequesters the free form and extends the half-life. Tirzepatide also has albumin binding…
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Follow-up: The most useful thing you learned here that was not the answer you came for Replied, post #26 · Lounge › Off topic · 15 Jul 2026 · 19 likes Lower-stakes conversation that does not belong in the technical categories. Still civil, still sourced when a claim is made, but the bar for relevance is lower.
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What a certificate commits its issuer to — the long version Replied, post #23 · Analytics › COA interpretation · 13 Jul 2026 · 2 likes Picking up post #20: that is the part I would want checked first. Sterility testing is separate: chromatographic purity, mass spectrometry, and endotoxin testing all…
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Reading a rodent study on a secretagogue without over-extrapolating — the long version Replied, post #36 · Compounds › Secretagogues & GH axis · 12 Jul 2026 · 1 like Worth separating two things that post #32 runs together. IGF-1 as a surrogate: it is a better integrated measure than a spot growth hormone level and it is still a…
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Endotoxin and why it is a separate question from purity — what changed since Replied, post #69 · Analytics › Impurities & related substances · 7 Jul 2026 · 17 likes Aggregates: multiples of the monomer mass. May not elute at all under a standard reversed-phase method. A species that does not come off the column does not appear in…
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SURPASS-2 and the comparator dose question that will not go away — what changed since Replied, post #4 · Compounds › Tirzepatide · 4 Jul 2026 · 24 likes Coming back to post #3, because the follow-up matters more than the original answer. SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes dose…
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Adolescents: a distinct evidence base Replied, post #3 · Clinical › Special populations · 3 Jul 2026 · 0 likes Hepatic impairment: less is known about dosing in significant liver disease than in kidney disease. Extreme caution applies because the liver metabolises a large…
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- LC-MS identity confirmationReview due 23 Mar 2027