hygroscopic raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-11. Anything still debated is marked as such rather than presented as settled.
The amino acid profile of collagen peptides is distinctive, with high proportions of glycine, proline, and hydroxyproline. These three residues make up roughly half of the total amino acid content in typical mammalian collagen. Hydroxyproline is formed by post-translational modification of proline and is uncommon in most other proteins. The presence of hydroxyproline serves as a marker for collagen-derived material in analytical testing. Peptide length and distribution depend on the hydrolysis conditions, including temperature, time, and enzyme or acid concentration.
Collagen peptides are typically sold as a powder that dissolves readily in cold or warm liquids. The powder is usually off-white to light yellow and has a mild taste, though some products may have a slight odor. Molecular weight distributions commonly range from about 1,000 to 5,000 daltons, but this varies by manufacturer and intended use. Smaller peptides are generally more soluble, while larger fragments may form viscous solutions. The material is hygroscopic and should be stored in sealed containers away from moisture and heat.
Storage and handling of collagen peptides require protection from moisture, heat, and light. The powders are hygroscopic and can absorb water from the air, leading to clumping or microbial growth. Typical storage conditions are a cool, dry place at room temperature or below, in tightly sealed containers. Some manufacturers recommend refrigeration for long-term stability. Solutions prepared from the powder are less stable and should be used promptly or preserved according to validated protocols.
Production of collagen peptides begins with raw materials such as bovine hide, porcine skin, fish scales, or poultry cartilage. The collagen is extracted, often with acid or alkaline treatment, and then subjected to hydrolysis using enzymes like pepsin or alcalase, or chemical agents. Enzymatic hydrolysis is favored for its mild conditions and controllability. The resulting mixture is filtered, concentrated, and dried to yield a powder. Process parameters such as temperature, pH, and enzyme-to-substrate ratio determine the molecular weight profile and yield.
Analytical methods for collagen peptides focus on molecular weight distribution, amino acid composition, and purity. Size exclusion chromatography with UV detection is widely used to estimate molecular weight ranges. High-performance liquid chromatography can quantify hydroxyproline after acid hydrolysis. Mass spectrometry provides detailed sequence information for individual peptides. Other tests include moisture content, ash, heavy metals, and microbial limits. The choice of method depends on the specific quality attribute and the required sensitivity.
| Property | Value | Notes |
|---|---|---|
| Appearance | Off-white to light yellow powder | Color may vary by source and processing. |
| Solubility | Soluble in water | Dissolves in cold or warm liquids; clarity depends on peptide size. |
| Typical molecular weight | 1,000–5,000 Da | Distribution varies with hydrolysis conditions. |
| Common source materials | Bovine hide, porcine skin, fish scales | Source affects amino acid profile and labeling. |
| Storage temperature | 15–25 °C | Keep sealed and away from moisture and heat. |
Theodosius II (r. 408–450) formalised Roman law by appointing five jurists as principal authorities and compiling legislation issued since Constantine's reign into the Codex Theodosianus. This process culminated in the Corpus Juris Civilis under Justinian I (r. 527–565), who commissioned a complete standardisation of imperial decrees since Hadrian's time and resolved conflicting legal opinions of the jurists. The result became the definitive legal authority. This body of law covered civil matters and also public law, including imperial power and administrative organisation. After 534, Justinian issued the Novellae (New Laws) in Greek, which marked a transition from Roman to Byzantine law. Legal historian Bernard Stolte distinguishes Roman law as this because Western Europe inherited law through the Latin texts of the Corpus Juris Civilis only. Zachary Chitwood argues that the Corpus Juris Civilis was largely inaccessible in Latin, particularly in the provinces. Following the 7th-century Arab conquests, people began questioning the development and application of law, leading to stronger ties between law and Christianity. This context influenced Leo III (r. 717–741) to develop the Ekloge ton nomon, which placed an emphasis on humanity. The Ekloge inspired practical legal texts like the Farmers' Law, Seamen's Law, and Soldiers' Law, which Chitwood suggests were used daily in the provinces as companions to the Corpus Juris Civilis.
== The conserved gene and its alleles == Thy-1 has been conserved throughout vertebrate evolution and even in some invertebrates, with homologs described in many species like squid, frogs, chickens, mice, rats, dogs, and humans. The Thy-1 gene is located at human chromosome 11q22.3 (mouse chromosome 9qA5.1). In AceView, it covers 6.82 kb, from 119294854 to 119288036 (NCBI 37, August 2010), on the reverse strand. This locus is very close to CD3 & CD56/NCAM genes. Some believe that there may be a functional significance of both this gene and CD3 delta subunit (T3D) mapping to chromosome 11q in man and chromosome 9 in mouse, though there is no homology (in fact this speculation led to its localization in chromosome 11q - the human chromosome region syntenic to mouse chromosome 9 which harbored T3D). In mice, there are two alleles: Thy-1.1 (Thy-1a, CD90.1) and Thy-1.2 (Thy-1b, CD90.2). They differ by only one amino acid at position 108; an arginine in Thy-1.1 and a glutamine in Thy-1.2. Thy-1.2 is expressed by most strains of mice, whereas Thy-1.1 is expressed by others such as AKR/J and PL mouse strains.
The concentrations of LSD in urine samples were followed over time at various temperatures, in different types of storage containers, at various exposures to different wavelengths of light, and at varying pH values. These studies demonstrated no significant loss in LSD concentration at 25 °C for up to four weeks. After four weeks of incubation, a 30% loss in LSD concentration at 37 °C and up to a 40% at 45 °C were observed. Urine fortified with LSD and stored in amber glass or nontransparent polyethylene containers showed no change in concentration under any light conditions. The stability of LSD in transparent containers under light depended on the distance between the light source and the samples, the wavelength of light, exposure time, and the light intensity. After prolonged exposure to heat in alkaline pH conditions, 10 to 15% of the parent LSD epimerized to iso-LSD. Under acidic conditions, less than 5% of the LSD was converted to iso-LSD. It was also demonstrated that trace amounts of metal ions in the buffer or urine could catalyze the decomposition of LSD and that this process could be avoided by the addition of EDTA.
== Isotope vs. nuclide == A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example, carbon-13 with 6 protons and 7 neutrons. Thus the terms are roughly the same, but the nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, whereas the isotope concept (grouping all atoms of each element) emphasizes chemical over nuclear. The neutron number greatly affects nuclear properties, but its effect on chemical properties is negligible for most elements. Even for the lightest elements, whose ratio of neutron number to atomic number varies the most between isotopes, it usually has only a small effect although it matters in some circumstances (for hydrogen, the lightest element, the isotope effect is large enough to affect biology strongly). The term isotopes (originally also isotopic elements, now sometimes isotopic nuclides) is intended to imply comparison (like synonyms or isomers). For example, the nuclides 126C, 136C, 146C are isotopes (nuclides with the same atomic number but different mass numbers), but 4018Ar, 4019K, 4020Ca are isobars (nuclides with the same mass number). As the older and better-known term, isotope is however still used in some contexts where nuclide might be more appropriate, such as in nuclear technology and nuclear medicine.
In one study in aged men with prostate cancer, testosterone levels were initially suppressed by 70%, but increased to 50% of baseline levels between 6 and 12 months, remaining stable thereafter up to 24 months of therapy. The combination of progestogens like CPA with an estrogen is synergistic in terms of antigonadotropic effect, and is able to fully suppress gonadal testosterone production even with very small doses of the estrogen. One study found that 100 to 300 mg/day CPA combined with an "extremely low" dosage of diethylstilbestrol (0.1 mg/day), a nonsteroidal estrogen, suppressed testosterone levels into the castrate range (to 30 ng/dL) in men with prostate cancer. Discontinuation of diethylstilbestrol at 5 months resulted in a rapid 6-fold increase in testosterone levels (to 135 ng/dL) and then further (to almost 200 ng/dL) by 12 months. Another study likewise found that the combination of 160 mg/day oral megestrol acetate, a progestin closely related to CPA, with 0.5 to 1.5 mg/day oral estradiol suppressed testosterone levels into the castrate range in men with prostate cancer. A study by Fung and colleagues (2017) found no difference in suppression of circulating testosterone levels (~95% suppression) in transgender women by the combination of either 25 mg/day oral CPA or 50 mg/day oral CPA with a moderate dosage of oral or transdermal estradiol (mean 3.3 mg/day oral, 3.4 g/day gel, or 95.6 μg/day patches).
Sources: en.wikipedia.org
2 December – Neville Callaghan, 77, racehorse trainer. 5 December – Rosemary Smith, 86, rally driver. 7 December – Thomas Kilroy, 89, playwright and novelist. 10 December Jonathan Irwin, 82, blood stock agent, auctioneer, stud owner, publisher and founder of the Jack and Jill Foundation. Syd Millar, 89, rugby union player (Ballymena, national team), coach (British & Irish Lions) and International Rugby Board chairman (2003–2007). Born in Northern Ireland. Bill McCarthy, 87, hurler (St Brendan's, Ardfert, Kerry junior team, Munster). 11 December – Frank Twomey, 68, children's television entertainer and comedian (Bosco, Bull Island). 16 December – Joseph Finnegan, 81, judge. 17 December – Maureen Flavin Sweeney, 100, postmistress and formerly a weather forecaster notable for advising on the D-Day landings. 20 December – Johnny Flaherty, 76, hurler (Kinnitty, Offaly senior team, Leinster). 21 December – Martin Feeley, 73, Olympic rower (1976) and surgeon. 27 December – Éamonn Draper, 83, actor and director. 28 December – Patrick Walsh, 92, Roman Catholic prelate, bishop of Down and Connor (1991–2008). 30 December – Paddy Murphy, 89, Gaelic footballer (Dromtarriffe, Duhallow, Cork senior team.
== Definition == In ISO/TS 80004, nanomaterial is defined as the "material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale", with nanoscale defined as the "length range approximately from 1 nm to 100 nm". This includes both nano-objects, which are discrete pieces of material, and nanostructured materials, which have internal or surface structure on the nanoscale; a nanomaterial may be a member of both these categories.
Although follicles were previously thought gone in areas of complete baldness, they are more likely dormant, as recent studies have shown the scalp contains the stem cells from which the follicles arose. Research on these follicular stem cells may lead to successes in treating baldness through hair multiplication (HM), also known as hair cloning. Per a May 2015 review, no successful strategy to generate human hair follicles, for hair regrowth, from adult stem cells has yet been reported. However, in April 2016, scientists from Japan published results of their work in which they created human skin from induced pluripotent stem cells; implanted into laboratory mice, the cells generated skin with hair and glands.
distal Wallerian degeneration distal sensory and motor deficits nerve conduction distal to the site of injury (3 to 4 days after injury) absent fibrillation potentials (FP), and positive, sharp EMG waves (2 to 3 weeks post injury). axonal regeneration and recovery does not typically require surgical treatment, although surgical intervention may be required, due to scar tissue
The protein tropomyosin covers the myosin-binding sites of the actin molecules in the muscle cell. For a muscle cell to contract, tropomyosin must be moved to uncover the binding sites on the actin. Calcium ions bind with troponin C molecules (which are dispersed throughout the tropomyosin protein) and alter the structure of the tropomyosin, forcing it to reveal the cross-bridge binding site on the actin. The concentration of calcium within muscle cells is controlled by the sarcoplasmic reticulum, a unique form of endoplasmic reticulum in the sarcoplasm. Muscle cells are stimulated when a motor neuron releases the neurotransmitter acetylcholine, which travels across the neuromuscular junction (the synapse between the terminal button of the neuron and the muscle cell). Acetylcholine binds to a post-synaptic nicotinic acetylcholine receptor. A change in the receptor conformation allows an influx of sodium ions and initiation of a post-synaptic action potential. The action potential then travels along T-tubules (transverse tubules) until it reaches the sarcoplasmic reticulum. Here, the depolarized membrane activates voltage-gated L-type calcium channels, present in the plasma membrane. The L-type calcium channels are in close association with ryanodine receptors present on the sarcoplasmic reticulum. The inward flow of calcium from the L-type calcium channels activates ryanodine receptors to release calcium ions from the sarcoplasmic reticulum. This mechanism is called calcium-induced calcium release (CICR).
Sources: en.wikipedia.org
This article incorporates text from a publication now in the public domain: Beccari, Camillo (1907). "Beatification and Canonization". In Herbermann, Charles (ed.). Catholic Encyclopedia. Vol. 2. New York: Robert Appleton Company.
Snakes commonly involved in envenomations include elapids (such as kraits, cobras and mambas), vipers, and sea snakes. The majority of snake species do not have venom and kill their prey by constriction (squeezing them). Venomous snakes can be found on every continent except Antarctica. Determining the type of snake that caused a bite is often not possible. The World Health Organization says snakebites are a "neglected public health issue in many tropical and subtropical countries", and in 2017, the WHO categorized snakebite envenomation as a Neglected Tropical Disease (Category A). The WHO also estimates that between 4.5 and 5.4 million people are bitten each year, and of those figures, 40–50% develop some kind of clinical illness as a result. Furthermore, the death toll from such an injury could range between 80,000 and 130,000 people per year. The purpose was to encourage research, expand the accessibility of antivenoms, and improve snakebite management in "developing countries". Prevention of snake bites can involve wearing protective footwear, avoiding areas where snakes live, and not handling snakes. Treatment partly depends on the type of snake. Washing the wound with soap and water and holding the limb still is recommended. Trying to suck out the venom, cutting the wound with a knife, or using a tourniquet is not recommended. Antivenom is effective at preventing death from bites; however, antivenoms frequently have side effects. The type of antivenom needed depends on the type of snake involved.
On the other hand, a similar study (Brachmachari et al.) reported no statistically significant inhibition of the lacZ reporter gene when H-DNA was inserted into the genome of mammalian COS cells. Although studies suggest regulation of H-DNA, the mechanism is still under investigation. Potaman et al. associates the mechanism of gene regulation to the interactions between the H-DNA and the TATA box found in the promoter region of Na,K-ATPase. In H-DNA formations adjacent to a TATA box, the H-DNA structure destabilizes the T-A bonds essential for transcription. The interference with the TATA box inhibits the transcriptional machinery and transcription initiation which interferes with gene expression. Other mechanisms associated with the genomic expression of a genetic sequence in the presence of H-DNA involves TFOs. In vitro studies have highlighted a decrease in gene expression in the presence of TFOs in mammalian cells. Another possible mechanism presented by Valentina et al. suggest the 13-mer AG motif oligonucleotide triplex complex (TFO complex) downregulates the transcription of mRNA through competitive inhibition. Direct inhibition of gene expression from H-DNA is key to mutagenesis, replication inhibition, and even DNA recombination in the genome.
== Further reading == Whitten, Kenneth W.; Davis, Raymond E; Peck, M. Larry (2002). General chemistry. Fort Worth: Thomson Learning. ISBN 978-0-03-021017-4. Whitten, Kenneth W; Gailey, Kenneth D (1981). General chemistry. Philadelphia: Saunders College Pub. ISBN 978-0-03-057866-3. Petrucci, Ralph H.; Herring, F. Geoffrey; Madura, Jeffry; Bissonnette, Carey; Pearson (2017). General chemistry: principles and modern applications. Toronto: Pearson. ISBN 978-0-13-293128-1. Vogel, Arthur Israel; Furniss, B. S; Tatchell, Austin Robert (1978). Vogel's Textbook of practical organic chemistry. New York: Longman. ISBN 978-0-582-44250-4.
In 1906, the German expedition team of Albert Grünwedel explored the Kizil Caves. Albert von Le Coq, who worked under the direction Grünwedel, had to leave in June 1906 due to health problems. Grünwedel generally photographed and copied the murals, before removing those he considered essential. Most of the fragments removed are now in Museum of Asian Art (formerly Museum für Indische Kunst) in Dahlem, Berlin. Other explorers removed some fragments of murals, that may now be found in museums in Russia, Japan, Korea and United States. Although the site has been both damaged and looted, around 5000 square metres of wall paintings remain, These murals mostly depict Jataka stories, avadanas, and legends of the Buddha, and are an artistic representation in the tradition of the Hinayana school of the Sarvastivadas. Carbon-testing and stylistical analysis helped determine three main periods in the paintings at Kizil, which cover a period from 300 CE to 650 CE. The early art of Kizil correspond to the Western school of art in the Tarim Basin, and mainly displays influences from Gandhara and the Iranian world, particularly influence from the Hephthalites, and no influence from East Asia. The Kizil Caves were designated by the Germans by a series of names, and have been separately numbered by the Chinese. A correspondence chart has been produced by Rhie. Some very early caves, now numbered 90–17 to 90–24, have been discovered since the 1990s in the lower parts of the cliff at the entrance of the central valley.
Sources: en.wikipedia.org
They are produced by hydrolyzing collagen extracted from animal tissues, most commonly bovine hide, porcine skin, fish scales, or eggshell membrane. The source material determines the amino acid profile and may affect allergenicity.
Intact collagen is a large triple-helical protein that is poorly soluble in water. Hydrolysis breaks the triple helix into shorter peptide chains, which dissolve more readily and are absorbed differently in the digestive tract.
Gelatin is also produced by collagen hydrolysis, but it typically has a higher molecular weight and forms a gel when cooled. Collagen peptides undergo further hydrolysis to produce shorter chains that remain soluble and do not gel.
They are produced by hydrolyzing collagen from animal or fish sources using enzymes or chemicals. The process breaks the protein into shorter chains. Filtration, concentration, and drying follow to create a powder.