Category Archives: Chemistry

Zurich-based cleantech startup UniSieve, which has sustainability at its core, has landed around 3.9 million in a round led by Wingman Ventures, the GREEN DEAL Grant (from the European Innovation Council), and the EIT Climate-KIC initiative (from the European Institute of Innovation and Technology).

Founded in 2018, UniSieve supports companies from the chemical and energy industry in conserving energy and reducing waste. The high energy demand of state-of-the-art separation used purify chemical products is responsible for over 10% of global energy use. By challenging state-of-the-art separation technology.

The proprietary UniSieve membrane solution facilitates saving up to 90% of the energy required to purify the worlds most frequent chemical feedstocks. Customers can therefore significantly reduce greenhouse gas pollution, recover valuable chemicals, and save operational costs. In addition, highly efficient separation technologies are enabling technologies to increase the economic attractiveness andsustainability of the growing renewable chemicals market.

The fresh funds raised will allow UniSieve to establish pilot production and co-finance industrial testing at customers chemical sites. It is expected that the investment will sustain the startup until the closure of sales agreements for full-scale separation units

Lukas Weder from Wingman Ventures, who will be joining the board of UniSieve, explains the firms decision to invest: With UniSieve, we back a highly innovative platform technology which optimizes the production process of the worlds largest chemical feedstocks by significantly reducing the amount of energy used in the process. We truly believe the UniSieve team can significantly contribute to the net zero economy.

Originally posted here:
Swiss cleantech UniSieve lands 3.9 million to help the chemical and energy industry conserve energy and reduce waste - EU-Startups

Someone walks into a room, and you immediately react. Your palms sweat, your heartbeat quickens, you blush and maybe you stammer or tremble. Then, once theyve left your sight, you cant get them out of your mind. Its as if theyve cast a spell on you.

Everything about them feels right, the way they look, smell and taste, says Robert Navarra, PsyD, LMFT, MAC, Certified Gottman Therapist and Master Trainer. If this intense attraction is mutual, time seems to stand still when youre with this other person. But why? What is the chemistry of love, and why do we feel it with some people and not others?

Although the word "chemistry," referring to a romantic and sexual spark, is not official, scientific term, the phenomenon is indeed backed by science. Heres some proof: Helen Fisher, Ph.D., senior research fellow at the Kinsey Institute and author of Anatomy of Love, looked at MRI results of 17 subjects who were intensely in love. When the subjects looked at photographs of their loved ones, the resulting MRI scans showed the areas of their brains associated with reward and motivation and rich in the chemical dopamine were activated. So, Dr. Fisher explains, When people say they have chemistry with someone, theyre being accurate.

If only there were a way to predict who well have chemistry with dating would be so much easier. Unfortunately, explains Justin Lehmiller, Ph.D., research fellow at the Kinsey Institute and author of Tell Me What You Want, most of us cant foresee what well find bewitching. In fact, speed-dating studies have found that people often dont pick people with the traits they'd put on their wish lists, he says.

Although a mystery, Dr. Fisher has discovered a science-backed way to at least partially understand why we have chemistry with some people rather than others. From her studies of the brain, she has found four basic styles of thinking and behaving linked with four different brain systems: the dopamine, serotonin, estrogen and testosterone. Each system is associated biologically with a constellation of personality traits, she says.

Based on data from her study of 40,000 singles research for her book, Why Him? Why Her? she found that men and women dominant in dopamine traits (including novelty- and risk-seeking, curiosity, creativity and energy) are attracted to people like themselves. The same is true for the serotonin-dominant, who tend to be cautious, traditional, rule-following and respectful of authority. In these cases, similarity attracts, Dr. Fisher says.

Meanwhile, those who are high in testosterone tend to be analytical, logical, direct, decisive, tough-minded and skeptical and more drawn to those who are dominant in the traits linked with estrogen, their opposites. Estrogen-dominant men and women tend to be imaginative, empathetic, trusting and emotionally expressive, as well as drawn to those high in testosterone, also their opposites. That said, Dr. Fisher points out that we all have traits in all four systems. Only when you see the full combination of traits in both partners can you begin to predict their compatibility, she says. (To see where you land, take Dr. Fishers free personality quiz on her website.)

Chemistry tends to be a launching pad for relationships, says Carrie Cole, M.Ed., L.P.C., research director and Gottman Master Trainer at The Gottman Institute. Chemistry opens the door, but its what we do with it afterwards that determines whether the relationship will have any legs, she says.

For relationships to progress beyond the initial intense attraction, trust and commitment must follow. Trust is knowing your partner is there for you and is someone you can count on, Dr. Navarra explains. Commitment is knowing there is no one else you would rather be with, and vice versa. Relationships typically start with chemistry, but need more to work.

Although chemistry can lead to successful relationships, it should be taken with a grain of salt, Dr. Lehmiller notes. After all, chemistry and compatibility are two different things, and sometimes the people we feel an overwhelming attraction to are not right for us long-term," she says. "People can get into trouble by rushing to commit to someone when they prioritize chemistry over shared interests and values. Instead, he says, people should try try to strike the right balance between chemistry and compatibility when looking for a long-term partner.

Chemistry with a long-term partner can fade, Dr. Lehmiller says. If it does, that doesnt mean theres a problem with your relationship. Theres also no need to panic if you experience chemistry with someone outside of your relationship, Dr. Fisher says. You can simultaneously be deeply attached to your partner, madly in love with someone else and sexually attracted to others, she explains. Thats because companionate love (for a long-term partner), romantic love and lust are orchestrated by three different brain systems, which operate in tandem.

Instead of panicking about a decline in chemistry, reinvest in your relationship by trying to rebuild that spark, Dr. Lehmiller says. To do so, focus on how you and your partner first met and what brought you together and to try to relive those initial moments. When couples tell me how they first met, they light up and turn towards each other, Cole says

Then, carve out regular rituals that encourage your connection, whether theyre weekly date nights or five-minute chats each evening to review your days, Dr. Navarra says. In fact, Dr. Lehmiller suggests spending some of this time asking each other deep questions, as with Dr. Arthur Arons 36 questions that lead to love, as published in The New York Times. Getting to know each other better on a deep level can actually help build chemistry. The more couples turn toward one another, the more theyll want to turn towards each other, Cole says.

Finally, since novelty boosts arousal, its a good idea to be adventurous with your partner; youll likely transfer some of the excitement from new experiences onto them. So, plan a date during which you learn a skill (like rock-climbing or painting), try a cuisine thats unfamiliar to you or explore a new neighborhood. The surge of dopamine youll likely experience might be just the ticket to add a spark to your long-term relationship.

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Romantic Chemistry Explained - What Is the Science Behind Attraction? - GoodHousekeeping.com

"Digital analytics in the chemical and petrochemical segments will enable machine-to-machine communication, resulting in automated solutions," said Janani Balasundar, Measurement & Instrumentation Research Analyst at Frost & Sullivan. "Vendors can generate demand for analyzers by improving operational efficiency through automated runs to help deduce mistakes early in the analytical process, thus helping companies struggling with pressures on pricing and margins."

Balasundaradded: "From a regional perspective, Asia-Pacific (APAC) has the largest market share for global aliphatic hydrocarbons in the petrochemical industry. Similarly, North America will witness considerable growth in the chemicals and petrochemicals market due to the presence of significant manufacturing industries. Europe, however, will have slow growth in the chemical and petrochemical segments due to strict environmental regulations."

To tap into the growth prospects presented by analytical instruments in the chemical and petrochemical industries, market participants need to focus on:

Market for Analytical Instruments in the Chemical and Petrochemical Industries, Forecast to 2026is the latest addition to Frost & Sullivan's Measurement & Instrumentation research and analyses available through the Frost & Sullivan Leadership Council, which helps organizations identify a continuous flow of growth opportunities to succeed in an unpredictable future.

About Frost & Sullivan

For over five decades, Frost & Sullivan has become world-renowned for its role in helping investors, corporate leaders and governments navigate economic changes and identify disruptive technologies, Mega Trends, new business models and companies to action, resulting in a continuous flow of growth opportunities to drive future success. Contact us: Start the discussion.

Market for Analytical Instruments in the Chemical and Petrochemical Industries, Forecast to 2026

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Market for Analytical Instruments in Chemical and Petrochemical Industries to Jump to $3.5 Billion by 2026 - PR Newswire India

Artists impression of young Earth. Credit: NASAs Goddard Space Flight Center Conceptual Image Lab

In the search for the chemical origins of life, researchers have found a possible alternative path for the emergence of the characteristic DNA pattern: According to the experiments, the characteristic DNA base pairs can form by dry heating, without water or other solvents. The team led by Ivan Halasz from the Ruer Bokovi Institute and Ernest Metrovi from the pharmaceutical company Xellia presents its observations from DESYs X-ray source PETRA III in the journal Chemical Communications.

One of the most intriguing questions in the search for the origin of life is how the chemical selection occurred and how the first biomolecules formed, says Tomislav Stolar from the Ruer Bokovi Institute in Zagreb, the first author on the paper. While living cells control the production of biomolecules with their sophisticated machinery, the first molecular and supramolecular building blocks of life were likely created by pure chemistry and without enzyme catalysis. For their study, the scientists investigated the formation of nucleobase pairs that act as molecular recognition units in the Deoxyribonucleic Acid (DNA).

From the mixture of all four nucleobases, A:T pairs emerged at about 100 degrees Celsius and G:C pairs formed at 200 degrees Celsius. Credit: Ruer Bokovi Institute, Ivan Halasz

Our genetic code is stored in the DNA as a specific sequence spelled by the nucleobases adenine (A), cytosine (C), guanine (G) and thymine (T). The code is arranged in two long, complementary strands wound in a double-helix structure. In the strands, each nucleobase pairs with a complementary partner in the other strand: adenine with thymine and cytosine with guanine.

Only specific pairing combinations occur in the DNA, but when nucleobases are isolated they do not like to bind to each other at all. So why did nature choose these base pairs? says Stolar. Investigations of pairing of nucleobases surged after the discovery of the DNA double helix structure by James Watson and Francis Crick in 1953. However, it was quite surprising that there has been little success in achieving specific nucleobase pairing in conditions that could be considered as prebiotically plausible.

Nucleobase powder and steel balls in a milling jar. Credit: Ruer-Bokovi-Institut, Tomislav Stolar

We have explored a different path, reports co-author Martin Etter from DESY. We have tried to find out whether the base pairs can be generated by mechanical energy or simply by heating. To this end, the team studied methylated nucleobases. Having a methyl group (-CH3) attached to the respective nucleobases in principle allows them to form hydrogen bonds at the Watson-Crick side of the molecule. Methylated nucleobases occur naturally in many living organisms where they fulfil a variety of biological functions.

In the lab, the scientists tried to produce nucleobase pairs by grinding. Powders of two nucleobases were loaded into a milling jar along with steel balls, which served as the grinding media, while the jars were shaken in a controlled manner. The experiment produced A:T pairs which had also been observed by other scientists before. Grinding however, could not achieve formation of G:C pairs.

In a second step, the researchers heated the ground cytosine and guanine powders. At about 200 degrees Celsius, we could indeed observe the formation of cytosine-guanine pairs, reports Stolar. In order to test whether the bases only form the known pairs under thermal conditions, the team repeated the experiments with mixtures of three and four nucleobases at the P02.1 measuring station of DESYs X-ray source PETRA III. Here, the detailed crystal structure of the mixtures could be monitored during heating and formation of new phases could be observed.

At about 100 degrees Celsius, we were able to observe the formation of the adenine-thymine pairs, and at about 200 degrees Celsius the formation of Watson-Crick pairs of guanine and cytosine, says Etter, head of the measuring station. Any other base pair did not form even when heated further until melting. This proves that the thermal reaction of nucleobase pairing has the same selectivity as in the DNA.

Our results show a possible alternative route as to how the molecular recognition patterns that we observe in the DNA could have been formed, adds Stolar. The conditions of the experiment are plausible for the young Earth that was a hot, seething cauldron with volcanoes, earthquakes, meteorite impacts and all sorts of other events. Our results open up many new paths in the search for the chemical origins of life. The team plans to investigate this route further with follow-up experiments at P02.1.

Reference: DNA-specific selectivity in pairing of model nucleobases in the solid state by Tomislav Stolar, Stipe Lukin, Martin Etter, Maa Raji Linari, Krunoslav Uarevi, Ernest Metrovi and Ivan Halasz, 9 September 2020, Chemical Communications.DOI: 10.1039/D0CC03491F

Original post:
Searching for the Chemistry of Life: Possible New Way to Create DNA Base Pairs Discovered - SciTechDaily

University of Massachusetts, Amherst, researchers have taken what they claim is an unprecedented objective approach to identify which genes and molecular pathways including mechanisms involving aging, lipid metabolism, and autoimmune diseaseare most sensitive to chemical exposure. Headed by environmental health scientist Alexander Suvorov, Ph.D., the research findings could help to improve our understanding of how chemicals, including pollutants and pharmaceuticals, interact to impact gene expression, and potentially human health.

When we identified all the sensitive genes, we were very much surprised that almost every well-known molecular pathway is sensitive to chemicals to a certain degree, said Suvorov, who is an associate professor in the School of Public Health and Health Sciences. These findings for the first time prove that current epidemics in metabolic and autoimmune disorders may be partly due to a very broad range of chemical exposures. Suvorov is first author of the teams published paper inChemosphere, which is titled, Unbiased approach for the identification of molecular mechanisms sensitive to chemical exposure.

Research estimates that the total burden of disease costs associated with exposure to environmental chemicals could be more than 10% of global domestic product, the authors commented. The number of new chemicals is also on a rapid increase, with the Chemical Abstract Service Registry increasing from 20 million to 156 million chemicals between 2002 and 2019. This situation poses a significant challenge for regulatory toxicology and requires the development of new, rapid, cost-efficient, and reliable methods of toxicity testing, Suvorov and colleagues commented.

Today, toxicologists recognize many molecular mechanisms that are key to a significant portion of all toxicity events, but all of these mechanisms were identified when there were no high-throughput methods for use in toxicology research. In the recent past, everything that we knew about molecular mechanisms affected by chemicals was coming from low-throughput experiments, Suvorov said, which led toxicology researchers to focus on those already identified genes, rather than looking for chemical sensitivity among a fuller range of genes.

What hasnt been known is whether all of the major mechanisms of toxicity have already been discovered using such historical approaches, or if there may be others that have been overlooked. Here, we hypothesized that data from toxicological omics experiments rapidly accumulating in publicly accessible databases may help to answer this question, the investigators commented.

To carry out their analysis, Suvorov and five studentsundergraduates Victoria Salemme, Joseph McGaunn, and Menna Teffera, and graduate students Anthony Poluyanoff, PhD, and Saira Amir, PhDextracted data on chemical-gene interactions from the Comparative Toxicogenomics Database (CTD), which includes human, rat, and mouse genes. In this study, we use publicly available data from the CTD, on changes in gene expression in response to a broad range of chemical compounds to identify, in an unbiased manner, the molecular mechanisms most sensitive to chemical exposure, the scientists noted. They created a database of 591,084 chemical-gene interactions reported in 2,169 studies that used high-throughput gene expression analysis, meaning that they looked at multiple genes; low-throughout analysis focuses only on a single gene.

I wanted to find some approach that would tell us in a completely unbiased way which mechanisms are sensitive and which are not, Suvorov said. I wondered if we were missing a significant toxic response just because no one ever looked for it. By overlaying many high-throughput studies, we can see changes in the expression of all genes all at once. And that is unbiased because we are not cherry-picking any particular molecular mechanisms.

The interactions analyzed encompassed 17,338 unique genes and 1,239 unique chemicals. The researchers split their database of chemicals into two parts, pharmaceutical chemicalswhich are designed to target known molecular cascadesand other chemicals such as industrial, agricultural, cosmetics, and pollutants. When the sensitivity of genes to pharmaceutical chemicals was compared to the sensitivity of genes to the other chemicals, the results were the same. That proves that when analysis is done on really big numbers of chemicals, their composition does not matter, Suvorov said.

The study confirmed the molecular mechanisms that had previously been recognized as being sensitive to chemical exposure, such as oxidative stress. But the new findings that the pathways involving aging, lipid metabolism, and autoimmune disease are also highly sensitive, suggest that chemical exposures may have a role in conditions such as diabetes, fatty liver disease, lupus, and rheumatoid arthritis. Many of the pathways identified play important roles in different kinds of cancer, for example. Among the highest-scoring genes for suppressive interactions, there were important members of the GH-IGF signaling cascade (GHR, IGFBP3, and IGF1), cytokines (CXCL8, CXCL12, CCL2), cyclins (CCNB1, CDK1, CCNA2, CCND1), lipid metabolism genes (THRSP, HMGCS1, FASN), and more, the team reported. One important question that remains unanswered is what pathways should be covered by in vitro assays to ensure that we do not miss possible toxicities of chemicals using this new paradigm of toxicity testing. Should there be evidence connecting these pathways with adverse outcomes, these pathways must be included in the list of targets for in vitro testing.

The researchers said the results indicate that the majority of known molecular pathways are sensitive to chemical exposure. Our data suggest that almost every known molecular pathway may be affected by chemical exposures, they wrote. Lipid metabolism was one mechanism that was found to be sensitive to a broad range of chemical agents. This finding may have significant public health implications and requires additional research, the team commented. Another group of molecular pathways identified as highly sensitive to chemical exposures consists of immune response pathways. The ability of a broad range of chemicals to suppress expression of genes essential for beta-cell development and function may be a significant factor that predisposes the modern population to diabetes development, they continued. Immune mechanisms that are dysfunctional in allergy and autoimmunity were also among those that were found to be highly sensitive to chemical exposures.

Suvorov concluded, This study represents a significant step forward in the use of genomic data for the improvement of public health policies and decisions and the public health field will benefit from a future focus of toxicological research on these identified sensitive mechanisms.

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New Research Shows the Sensitivity of Thousands of Genes to Chemical Exposure - Clinical OMICs News

Some of you screwballs out there have been complaining that I'm not giving enough chemistry lessons. No accounting for taste. If you'd asked me a few years ago when I first started writing these miserable thingsI would have doubted thatmy own family would bother to read them, but it turns out that they've become strangely popular.

So, let's do another.

THE MORE OR LESS SORDID HISTORY OF HEROIN

Here's the first journal articleon the synthesis of heroin. It is long and complex, despite the fact that the conversion of morphine to heroin is (now) a trivial reaction that can be done in minutes.

The title of the first reported synthesis of heroin. Wright, C. R. A.: On the action of organic acids and their anhydrides on the natural alkaloids, Journal of Chemical Society, 1874, 12, 1031. The paper contains no chemical structures, only molecular formulas. Does anyone know why? (1)

Source: Journal of the Chemical Society

OK, it's time...

Making Heroin is Easy Peasy. But it wasn't in 1874

Our progress in fightingpain hasn't progressed much since 1874, but organic chemistry has. It took four pages of experimental details for Wright to describe the procedure for the synthesis, purification, and analysis of the heroin he made. All of this for one very simple reaction...

Acetylation of morphine: Two hydroxyl groups react with acetic anhydride to form two acetateesters (red boxes) (heroin).

By contrast, the synthesis of aspirin from salicylic acid an almost identicalchemical reaction takes10 minutes(plus a little purification time) in an experiment suitedfor high schoolor organic 101 students.

Salicylic acid contains one hydroxyl group, which is easily acetylated to form aspirin. The acetyl group is shown in the red box.

See how similar the two reactions are?

ASPIRIN VS. HEROIN

In the 1890s Felix Hoffman, a German chemist working for Bayerwas acetylating everything in sightto examine the change in properties ofchemicals/drugs when hydroxyl groups are converted to acetate esters. Although Hoffman wasn't the first person to synthesize either aspirin or heroin, he did make both for Bayer, which sold both of them...at the same time... and in the same ad(!).

A Bayer ad, date unknown, selling both aspirin and heroin. Image: Bomb Magazine

You've withstood theDCLFHTM so what is your reward?

A BIOCHEMISTRY LESSON FROM HELL!

Why do the acetyl groups found inheroin and aspirin give the drugs enhanced properties compared to the hydroxylversions, morphine, and salicylic acid, respectively? The acetyl groups make a very big difference in the potency of the drugs in each case, but for different reasons.

ASPIRIN

Figure1: The inhibition of COX by aspirin. Aspirin forms a covalentbond to a serine group near the active site, which prevents the normal substrate from entering the channel to the catalytic (active) site ofthe enzyme.Source: Tulane University

Aspirin and other NSAIDs work by inhibiting a critical enzyme called cyclooxygenase (COX), which catalyzes the conversion ofa ubiquitous biomolecule,arachidonic acid (AA) into prostaglandinsand thromboxanesextremely potent hormones that have multiplefunctions throughout the body, including, pain and inflammation. As seen in Figure1, aspirin (4) fits into the channel in COX that leads to the catalytic (active) site (black dot).

Once there, the acetyl group, whichis chemically reactive,reacts irreversiblywith the serine another way of saying that aspirin transfersthe acetyl group to COX forming a covalent bond.Once theserine group of the enzyme has been acetylated things grind to a halt; the enzyme is inactivated.Arachidonic acid can no longer reach the catalytic site on COX so it cannot be convertedtoprostaglandins and thromboaxnes.This explains why aspirin, ibuprofen, etc.treatpain, fever, and inflammation (and also why they screw up your stomach.)

MAKING SENSE OF MORPHINE AND HEROIN

The function of the acetyl groups in heroin is completely different than thatin aspirin. In this case, they aremerely delivery devices -sort of molecular UPS trucks.

The two hydroxyl groups in morphine make themolecule hydrophilic (water-loving the opposite of lipophilic fat-loving). Lipophilic molecules are usually better at penetrating cells (and also getting into the brain) because they can pass more easily through cell membranes. Lipophilicityis measured or calculated(2) and expressed by a unit called logP, the higher the value the more lipophilic the molecule. (P is called the partition coefficient.Don't ask.) All you need to know is this:

A drug targeting the central nervous system (CNS) should ideally have a logP value around 2

Source: ACD Labs

Now, let's look at the logP values for morphine, heroin, and its primarymetabolite, 6-monoacetylmorphine. It should not be surprising that each time anacetyl group replaces a hydroxyl groupthe molecule becomesmore lipophilic. (For the chemical structure of these drugs see Figure 2 below.)

Morphine (two hydroxyl group)- 0.8

6-Monoacetylmorphine (one hydroxy group) -1.3

Heroin (no hydroxyl groups) -1.5

Sorry to interrupt your coma, but there is a bit more information you need to know in order to understand why heroin behaves like heroin metabolism.

Although heroin's logPis closeto 2 the ideal value for CNS drugs the difference between it and morphine, 0.7 doesn't seem like a big deal. But keep in mind thata 0.7 log10 unit difference means that heroin is6.5-timesmore lipophilic than morphine, so it gets to the brain more easily (this explains the "heroin rush").

Heroin's two acetyl groups are metabolized at different rates and atdifferent places in the body. This what makes heroin such an effective and deadly drug.

Figure 2. Metabolism of heroin. Original Source: Science Direct

Step 1. The acetyl group at the 3 position of heroin(3) (red box) is very reactive. It is cleaved by esterase enzymesin the blood in a few minutes, forming 6-monoacetylmorphine (6-MAM). This reaction occurs so quickly that heroin doesn't even reach the brain. And if it did, it wouldn't matter because heroin itself is not an opioid agonist.

Step 2. 6-MAM is also deacetylatedin the blood, formingmorphine, but not so fastthat it cannot reach the brain. It does so very quickly. In fact,6-MAM itselfis a mu-opioid agonist and this is probablywhy heroin packs more of a punch than morphine. Additionally, 6-MAM isdeacetylatedby the brain to give morphine.

It is not completely clear whether the "heroin rush" is due to 6-MAM itself, the rapid delivery of 6-MAM to the brain where it is converted to morphine, or both. But it doesn't really matter. Heroin is a very effective pro-drug of morphine (and/or 6-MAM).

It's amazing, in a twisted sort of way, that heroin, the scourge of mankind (at least until fentanyl came along) is a quintessential example of the power of pro-drugs.

Chemistry lesson over. Biochemistry lesson over.

You can wake up now.

NOTES:

(1) At this time chemical structures were unknown. Chemists could not determine how the atoms of a molecule were connected, only the molecular formula of that molecule.

(2) Virtually all the numbers given for logP are calculated, not measured. To do this, itwould take an eternity and cause chemists to be hurling themselvesinto the Kilauea Volcano. I have no idea how this calculation is done and am perfectly content to keep it that way.

(3) Why is that called the 3-position? Although there are rules for assigning numbers tomolecules for the purpose of naming them I'd rather drink nitric acid than go back and relearn them. Nomenclature makes organic chemists (more) crazy.

(4) Aspirin is the only NSAID to inhibit COX by forming a covalent bond. The others do so by tightly (but reversibly) binding to the enzyme.

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All the Chemistry You Never Wanted to Know About Heroin, & More - American Council on Science and Health