This is a working overview of freeze-thaw, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-14 and is reviewed periodically as new material appears.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Some prohormones contain structures other than inactive peptide hormones for the purpose of keeping hormone expression suppressed. For example, proinsulin contains an extra non-hormonal chain called C-peptide that binds two insulin peptide chains together, designed to keep both chains inactive by binding to their ends, specifically, their C-domain junctions, which have been proposed to be their site of binding to hormone-expression receptors in the cell. Despite the restrictions it enables, the C-peptide folds the proinsulin chains to make their junction ends accessible to be cleaved by prohormone convertases later, making the folding of the proinsulin chain containing C-peptide essential for the proper cleavage of proinsulin to successfully produce insulin.
The Chiefs of the staff branches answered to the Chief of the General Staff, whose post was held by a Lieutenant-General. To provide training for staff officers, the Indian Staff College was established in 1905, and permanently based at Quetta from 1907. With no intermediate chain of command, army headquarters was weighed down with minor administrative details. Divisional commanders were responsible not only for their active formations, but also for internal security and volunteer troops within their respective areas. On mobilisation, divisional staffs took the field, leaving no-one to maintain the local administration. Supporting services were insufficient, and many troops intended for the field force were not moved from their old stations into the areas of their new divisional command. These defects became clear during the First World War, and lead to further reorganisation. The Indian Army Act 1911 legislated the replacement of the Indian Articles of War 1869. It was passed by the Governor General. It was under aspects of this law that the Army charged defendants during the Indian National Army Trials in 1945. It was replaced by the "Indian Army Act, 1950" after partition and independence.
retinal + NADH + H+ ⇌ retinol + NAD+ retinol + NAD+ ⇌ retinal + NADH + H+ Retinal (also known as retinaldehyde) can be irreversibly converted to all-trans-retinoic acid by the action of retinal dehydrogenase
The proposed conformational transition is thought to allow the newly-generated coiled region (incorporating residues 'RRYLENGKETLQR' which have also been found to be naturally bound to HLA-B27 as a 9-mer peptide) to bind to either the peptide-binding cleft of the same polypeptide chain (in an act of self-display) or to the cleft of another polypeptide chain (in an act of cross-display). Cross-display is proposed to lead to the formation of large, soluble, high molecular weight (HMW), degradation-resistant, long-surviving aggregates of the HLA-B27 heavy chain. Together with any homodimers formed either by cross-display or by a disulfide-linked homodimerization mechanism, it is proposed that such HMW aggregates survive on the cell surface without undergoing rapid degradation, and stimulate an immune response. Three previously noted features of HLA-B27, which distinguish it from other heavy chains, underlie the hypothesis: (1) HLA-B27 has been found to be bound to peptides longer than 9-mers, suggesting that the cleft can accommodate a longer polypeptide chain; (2) HLA-B27 has been found to itself contain a sequence that has also been actually discovered to be bound to HLA-B27, as an independent peptide; and (3) HLA-B27 heavy chains lacking β2 microglobulin have been seen on cell surfaces.
Sources: en.wikipedia.org
MDMA is often said to have mild or weak psychedelic effects. These effects are said to be dose-dependent, such that greater hallucinogenic effects are produced at higher doses. The mild hallucinogenic effects of MDMA include perceptual changes like intensification of visual, auditory, and tactile perception (e.g., brightened colors), a state of dissociation with feelings of depersonalization and derealization (e.g., "oceanic boundlessness"), and thinking disturbances. Conversely, overt hallucinations do not occur, MDMA's hallucinogenic effects are described as "non-problematic" for users, and are said to be much less than those of 3,4-methylenedioxyamphetamine (MDA) or especially those of fully effective serotonergic psychedelics like psilocybin. The hallucinogenic effects of MDMA have been theorized to be mediated by serotonin 5-HT2A receptor activation analogously to the case of classical psychedelics. Accordingly, the serotonin 5-HT2A receptor antagonist ketanserin has been reported to reduce MDMA-induced perceptual changes in humans. Conversely however, it failed to affect MDMA-induced feelings of dissociation and oceanic boundlessness. In contrast, the serotonin reuptake inhibitor citalopram, which blocks MDMA-induced serotonin release, diminished all of the psychoactive and hallucinogenic effects of MDMA. It has been noted that N-methylation of psychedelic phenethylamines, as in the structural difference between MDA and MDMA, has invariably greatly reduced or abolished their psychedelic activity.
Although still under investigation, it now appears that the combination of melamine and cyanuric acid has been linked to the acute renal failure in cats and dogs that have eaten the suspect pet foods...." In the United States, five potential vectors of impact on the human food supply have been identified. The first, which has already been acknowledged to have occurred by FDA and USDA officials, is via contaminated ingredients imported for use in pet foods and sold for use as salvage in animal feed which has been fed to some number of hogs and chickens, the meat from which has been processed and sold to some number of consumers: "There is very low risk to human health" in such cases involving pork and poultry. On 1 May 2007, the FDA and USDA stated that millions of chickens fed feed tainted with contaminated pet food had been consumed by an estimated 2.5 to 3 million people. The second potential vector is via contaminated vegetable proteins imported for intended use as animal feed, which has apparently been acknowledged to occur with regard to fish feed in Canada, while the third possible route is via contaminated vegetable proteins imported for intended use in human food products, and the FDA has issued an import alert subjecting all Chinese vegetable proteins to detention without examination. A fourth potential vector is referred to on 10 May 2007 FDA-USDA press conference, viz. incorporation of contaminated vegetable proteins into products intended for human use and subsequent importation.
=== Discontinued === 1-Amino-5-bromouracil (ABU) – undefined mechanism of action [60] ABT-418 – nicotinic acetylcholine receptor agonist [61] ABT-436 – vasopressin V1B receptor antagonist [62] Adipiplon (NG-273) – GABAA receptor positive allosteric modulator and nonbenzodiazepine [63] Alnespirone (S-20499) – serotonin 5-HT1A receptor agonist [64] Alosetron (GR-68755; GR-68755C; Lotronex) – serotonin 5-HT3 receptor antagonist [65] Alpidem (Ananxyl; S-800342-001; SL-800342) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/imidazopyridine [66] Alprazolam lingual spray – GABAA receptor positive allosteric modulator and benzodiazepine [67] AN-788 (IP-2018; NSD788) – serotonin–dopamine reuptake inhibitor (SDRI) [68] AP-521 – serotonin 5-HT1A receptor partial agonist [69] Aprepitant (Emend; L-754030; MK-0869; MK-869; ONO-7436) – neurokinin NK1 receptor antagonist [70] AVN-211 (CD-008-0173) – serotonin 5-HT6 receptor antagonist [71] AVN-397 – undefined mechanism of action [72] AZD-2327 – δ-opioid receptor (DOR) agonist [73] AZD-8129 (AR-A000002; AR-A2XX; AR-A2) – serotonin 5-HT1B receptor antagonist [74] Befloxatone (MD-370503) – reversible inhibitor of monoamine oxidase A (RIMA) [75] Blarcamesine (AE-37; ANA001; ANAVEX 2-73) – sigma σ1 receptor agonist, muscarinic acetylcholine M1 receptor agonist, and ionotropic glutamate NMDA receptor agonist [76] Bretazenil (RO-166028) – GABAA receptor positive allosteric modulator and benzodiazepine [77] Brofaromine (Brofaremine; CGP-11305A; Consonar; Consonev) – reversible inhibitor of monoamine oxidase A (RIMA) and serotonin reuptake inhibitor (SRI) [78] Buspirone transdermal (BuSpar Patch) – serotonin 5-HT1A receptor partial agonist and other actions [79] CGS-12066 – serotonin 5-HT1B receptor partial agonist and other actions [80] Coluracetam (BCI-540; MKC-231) – ionotropic glutamate AMPA receptor positive allosteric modulator, choline uptake and acetylcholine synthesis enhancer, and racetam [81] DAA-1097 – translocator protein (TSPO) agonist [82] Devazepide (Devacade; L-364718; MK-329) – Cholecystokinin A (CCKA) receptor antagonist [83] Dipraglurant (ADX-48621; mGluR5-NAM) – metabotropic glutamate mGlu5 receptor negative allosteric modulator [84] Eglumetad (eglumegad; LY-354740) – metabotropic glutamate mGlu2 and mGlu3 receptor agonist [85] Emapunil (AC-5216; XBD173) – translocator protein (TSPO) agonist [86] Emicerfont (GW-876008; GW876008) – corticotropin releasing factor CRF1 receptor antagonist [87] Enciprazine (D-3112; WY-48624) – serotonin 5-HT1A receptor agonist and α1-adrenergic receptor ligand [88] Eplivanserin (Ciltyri; Sliwens; SR-46349; SR-46349B; SR-46615A) – serotonin 5-HT2A receptor antagonist [89] Eptapirone (F-11440) – serotonin 5-HT1A receptor agonist [90] Esprolol ((S)-ACC-9369) – beta blocker (β-adrenergic receptor antagonist) (amoxolol prodrug) [91] Flesinoxan (DU-29373) – serotonin 5-HT1A receptor agonist [92] Gabapentin (CI-945; Gabapen; GOE-3450; Neurontin) – gabapentinoid (α2δ subunit-containing voltage-gated calcium channel ligand) [93] Girisopam (EGIS-5810; GYKI-51189) – GABAA receptor positive allosteric modulator and benzodiazepine [94] GT-2203 – histamine H3 receptor agonist [95] Guanfacine (Guanfacine Carrier Wave project; SPD-554) – α2-adrenergic receptor agonist [96] Ipsapirone (BAY-Q-7821; TVX-Q-7821) – serotonin 5-HT1A receptor partial agonist [97] Isamoltane (CGP-361A) – beta blocker (β-adrenergic receptor antagonist) and serotonin 5-HT1A and 5-HT1B receptor antagonist [98] Itasetron (DAU-6215; U-98079) – serotonin 5-HT3 receptor antagonist [99] ITI-333 – serotonin 5-HT2A receptor antagonist, dopamine D1 receptor antagonist, α1A-adrenergic receptor antagonist, and μ-opioid receptor (MOR) partial agonist [100] JNJ-19567470 (CRA-5626; R-317573) – corticotropin releasing factor CRF1 receptor antagonist [101] Levetiracetam (Keppra; L-059; SIB-S1; UCB-059; UCB-22059; UCB-L059) – synaptic vesicle glycoprotein 2A (SV2A) ligand [102] Lorazepam intranasal – GABAA receptor positive allosteric modulator and benzodiazepine [103] Mavoglurant (AFQ-056; STP-7) – metabotropic glutamate mGlu5 receptor antagonist [104] Midazolam intranasal (ITI-111; midazolam nasal spray; Nayzilam; USL-261) – GABAA receptor positive allosteric modulator and benzodiazepine [105] MK-0777 (L-830982; TPA-023) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/triazolopyridazine [106] NBI-34041 (SB-723620) – corticotropin-releasing hormone (CRH) inhibitor [107] Nerisopam (EGIS-6775; GYKI-52322) – GABAA receptor positive allosteric modulator and benzodiazepine [108] Nivasorexant (ACT-539313; SORA) – orexin OX1 receptor antagonist [109] NS-11821 (NS11821) – GABAA receptor positive allosteric modulator and nonbenzodiazepine [110] Orvepitant (GW-823296; GW823296X) – neurokinin NK1 receptor antagonist [111] Osanetant (ACER-801; SR-142801; SR-142806) – neurokinin NK3 receptor antagonist [112] Panadiplon (FD-10571; FG-10571; NNC-140571; U-78875) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/pyrazolopyrimidine [113] Pazinaclone (A-77000; DN-2327) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/cyclopyrrolone [114] Pozanicline (A-87089.0; ABT-089) – nicotinic acetylcholine receptor agonist [115] Psilocybin (CYB-001; INT0052/2020) – non-selective serotonin receptor agonist and psychedelic hallucinogen [116] Research programme: depression and anxiety therapies - Roche/Vernalis – undefined mechanism of action [117] Research programme: GPCR modulators - Nxera Pharma – various actions [118] Research programme: monoamine oxidase A inhibitors - CeNeRx BioPharma – monoamine oxidase A (MAO-A) inhibitors [119] Ritanserin (R-55667) – serotonin 5-HT2 receptor antagonist and other actions [120] Robalzotan (AZD-7371; NAD-299) – serotonin 5-HT1A receptor antagonist [121] RS-127445 (MT-500) – serotonin 5-HT2B receptor antagonist [122] SAX-187 (WAY-181187) – serotonin 5-HT6 receptor agonist [123] Sergolexole (LY-281067) – serotonin 5-HT2 receptor antagonist [124] Siramesine (LU-28179) – sigma σ2 receptor agonist [125] SKL-PSY (FZ-016) – serotonin 5-HT1A receptor agonist [126] SSR-241586 (SSR241586) – neurokinin NK2 and NK3 receptor antagonist [127] SUN-8399 – serotonin 5-HT1A receptor agonist [128] Suriclone (RP-31264) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/cyclopyrrolone [129] Talaglumetad (LY-544344) – metabotropic glutamate mGlu2 and mGlu3 receptor agonist (eglumetad prodrug) [130] Tiagabine (A-70569; CEP-6671; Gabitril; NO-050328; NO-328) – GABA transporter 1 (GAT-1) blocker and GABA reuptake inhibitor Troriluzole (BHV-4157; Dazluma; FC-4157; trigriluzole) – various actions (riluzole prodrug) [131] Vestipitant (GW-597599) – neurokinin NK1 receptor antagonist [132] Zabaglurant (TMP-301; TMP301; Heptares 25; HTL-0014242; HTL14242) – metabotropic glutamate mGlu5 receptor negative allosteric modulator [133] Zalospirone (WY-47846) – serotonin 5-HT1A receptor agonist [134]
Sources: en.wikipedia.org
Florey was awarded the Cameron Prize for Therapeutics of the University of Edinburgh and the Lister Medal in 1945, for his contributions to surgical science. The corresponding Lister Oration, given at the Royal College of Surgeons of England later that year, was titled "Use of Micro-organisms for Therapeutic Purposes". He was awarded many honorary degrees from British and foreign universities, including University of São Paulo in Brazil. He won the Gold Medal of the Royal Society of Medicine in 1947. He became a commander of the French Legion of Honour in 1946 and was awarded the American Medal for Merit in 1948 and the James Smithson Medal in 1965. Florey was elected to the United States National Academy of Sciences and the American Philosophical Society in 1963, and was elected to the American Academy of Arts and Sciences the following year. He became an honorary Fellow of the Royal College of Surgeons in 1961. On 4 February 1965, Florey was created a life peer and became Baron Florey, of Adelaide in the Commonwealth of Australia and of Marston in the City of Oxford. This was a higher honour than the knighthood awarded to Sir Alexander Fleming, and it recognised the monumental work Florey had done in making penicillin available in sufficient quantities to save millions of lives. He was formally introduced to the House of Lords in April, sponsored by Lord Cottesloe, Margaret Jennings's brother, and Lord Adrian, one of Florey's predecessors as President of the Royal Society. On 15 July 1965 he was appointed a member of the Order of Merit.
All ordinary matter is made up of combinations of chemical elements, each with its own atomic number, indicating the number of protons in the atomic nucleus. Additionally, elements may exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus. A particular isotope of a particular element is called a nuclide. Some nuclides are inherently unstable. That is, at some point in time, an atom of such a nuclide will undergo radioactive decay and spontaneously transform into a different nuclide. This transformation may be accomplished in a number of different ways, including alpha decay (emission of alpha particles) and beta decay (electron emission, positron emission, or electron capture). Another possibility is spontaneous fission into two or more nuclides. While the moment in time at which a particular nucleus decays is unpredictable, a collection of atoms of a radioactive nuclide decays exponentially at a rate described by a parameter known as the half-life, usually given in units of years when discussing dating techniques. After one half-life has elapsed, one half of the atoms of the nuclide in question will have decayed into a "daughter" nuclide or decay product. In many cases, the daughter nuclide itself is radioactive, resulting in a decay chain, eventually ending with the formation of a stable (nonradioactive) daughter nuclide; each step in such a chain is characterized by a distinct half-life.
==== Efficacy ==== Some evidence shows that metformin is associated with weight loss in obesity in the absence of diabetes. Metformin has a lower risk of hypoglycemia than the sulfonylureas, although hypoglycemia has uncommonly occurred during intense exercise, calorie deficit, or when used with other agents to lower blood glucose. Metformin modestly reduces low density lipoprotein and triglyceride levels. In individuals with prediabetes, a 2019 systematic review comparing the effects of metformin with other interventions in the reduction of risk of developing type 2 diabetes found moderate-quality evidence that metformin reduced the risk of developing type 2 diabetes when compared to diet and exercise or a placebo. However, when comparing metformin to intensive diet or exercise, moderate-quality evidence was found that metformin did not reduce risk of developing type 2 diabetes and very low-quality evidence was found that adding metformin to intensive diet or exercise did not show any advantage or disadvantage in reducing risk of type 2 diabetes when compared to intensive exercise and diet alone. The same review also found one suitable trial comparing the effects of metformin and sulfonylurea in reducing the risk of developing type 2 diabetes in prediabetic individuals; however, this trial did not report any patient-relevant outcomes.
=== Other organic constituents === Nitrogen metabolism end products are present in the hemolymph in low concentrations. These include ammonia, allantoin, uric acid, and urea. Arthropod hormones are present, most notably the juvenile hormone. Trehalose can be present and sometimes in great amounts along with glucose. These sugar levels are maintained by the control of hormones. Other carbohydrates can be present. These include inositol, sugar alcohol, hexosamines, mannitol, glycerol and those components that are precursors to chitin. Free lipids are present and are used as fuel for flight.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.