Chemistry - Science topic

What equation? Do you mean the Michaelis-Menten equation? They can be determined graphically on the basis of the V = f (c_S) curve, or can be calculated using, for example, non-linear regression.

Pluronic F127 will make your surface hydrophilic:

Pluronic F127 sticks to hydrophobic surfaces via the central polypropylene oxide moiety, with the hydrophilic peg side arms sticking out, away from the surface, transforming the hydrophobic surface hydrophilic.

I agree that by encouraging student's creativity, it helps promote their leadership skills and guide them in decision-making process.

A perfect link to visualization.

Hi Luis, metabolomics studies the metabolome in a top-down, experimental manner. The metabolome comprehends the whole ensemble of small molecules, with grey limits within biological oligomers. Proteins, genes, transcripts, are not part of the metabolome, neither lipids or glycans in my opinion. While MS or NMR can/will 'virtually' be able to obtain information about any molecule, for sure it will not be in a high-throughput manner, measuring everything at the same time. In fact, metabolomics is the least high-throughput omic technique where robust bioinformatic pipelines are still under development when compared to proteomics, genomics, etc. Many analytical techniques are 'the true' technique to answer the problem to which the technique is focused to retrieve data valuable to be evaluated.

As the contributions in this thread are documenting, there are obviously some highly emotional aspects concerning author's lists...

In my field, typically the first author is the one who did most of the work and I never really understood the discussions about the ranking after place 1. I am always happy if everyone is included who contributed with anything and alphabetical order is ok for me.

The world would probably better if we could put away our vanity more often.

Endnote

Mendely

Origin

ChemDraw

Docking

Rstudio

Matlab

there are many soft wares, it depends on your work.

It would be interesting to explore the differences between physics and chemistry.

Dear Reads Nima Tabatabaei Rezaei,

Have you tried the way I propose to go ahead for the same? Just try it.Somebody has done and successfully got some very interesting synthesis results.

Because of the good thermal stability and superior carrier transport characteristics of formamidinium lead trihalide perovskite HC(NH2)2PbX3 (FAPbX3) has been considered to be a better optoelectronic material than conventional CH3NH3PbX3 (MAPbX3). The FAPbBr3 photodetector’s responsivity to two-photon absorption with an 800-nm excitation source can reach 0.07 A W−1, which is four orders of magnitude higher than that of its MAPbBr3 counterparts. Materials such as Formamidine acetate, lead bromide (PbBr2, > 98%) and hydrobromic acid (48 wt% in water), Gamma-butyrolactone (GBL) and N,N-dimethylformamide (DMF) may required for synthesis.

Formamidinium iodide (FAI) and formamidinium bromide (FABr) can be synthesised by dissolving formamidinium acetate powder in a 2x molar excess of 57%w/w hydroiodic acid (for FAI) or 48%w/w hydrobromic acid (for FABr). FABr can be synthesized by slowly dropping 10 mL hydrobromic acid into 50 mmol (5.205 g) formamidine acetate in a flask, accompanied by continuous stirring at 0 °C for 2 h under argon atmosphere. The product FABr was formed once the solvent was removed using a rotary evaporator at 70 °C. The crude white powder was dissolved in ethanol and subsequently reprecipitated in diethyl ether. Then, the filtered product was dried at 60 °C in a vacuum oven for 24 h for further use.

Ashish

Claire Boyer I think that simply soaking the fibrous mat in a solution of Cu(acac)₂ in dichloromethane over night will be sufficient to impregnate the pores of the MOF with the copper precursor. As suggested earlier, use dichloromethane instead of chloroform to dissolve you Cu(acac)₂.

P.S. When other RG members help you by answering your questions, it is polite and a good practice on RG to recommend their answers.... 😎

Dear Michael Pujari-Palmer, why don't you use directly AFM for contact measurement? My Regards

Dear Ana

If you intend to determine all double bonds (including aromatic, carbonyl and etc) I recommend using the NMR analysis, although you will need a specific lab, this equipment is usual in chemical departments.

Some articles may help you with this problem.

Hi Alida, this is a really good question. I think that the basis for this is the combination of basic and acidic dyes to stain acidic/basophilic, and basic/acidophilic molecules in tissue, respectively. I realize that your question is really asking why some stains won't work without their counterpart. I know that you must use basic dyes before acidic dyes, and alcohol before aqueous, otherwise staining will not work. I suggest Animal tissue techniques (A Series of books in biology) 3rd ed. by Gretchen L Humason. It was published in 1972, but is still one of the best histology books I've ever seen. You can get it on amazon for about $10, ISBN-10: 9780716706922 .

Dear Maciej Spiegel ,

If you were using Gaussian09, you might wanna try b97d3 or wb97xd functional which includes a better dispersion correction.

Try Zinc15 or VulcanChem (https://www.vulcanchem.com/) Or a vendor listed on PubChem. They are usually more responsive than others found on the Internet.

Please go to this link:

@Muhammad Shoaib thanks for asking this question. The answers here my mind to a greater extent.thanks

It depends on the topic and process of the university and the cooperation of supervisors as well.

Approximately 3-4.

With precise oscillatory pattern much less perturbed by external stimuli, it can act as precise "timing" device without any internal electronics and piezoelectrics (only external laser pulses would be enough). The molecular machines with sustained fixed rotational speeds (e.g. molecular analogue of synchronous motor) can be made this way. If time crystal is made of quantum-entangled particles, the entanglement would be more robust and less prone to decoherence instead of external perturbations, using them as quantum level memory element- but rather the memory would be volatile-as continuous external energy has to be applied to keep the time-crystal tendency going. The pulse, if can be coupled with delocalized electron system of an organic molecule, can provide pulsating electronic excitation (which may be tailored by attenuation/amplification with certain functional groups). Samely, phase modulation of pulses can create a much robust and compact phased array, that is far more thermal oscillation insensitive and more importantly, can circumvent centrosymmetry constraints and requirement of enough molecules to construct a reasonable periodicity of a piezoelectric crystal. However, if pulsating device with a few molecules can be constructed, then this aspect of time crystals can be greatly diminished. Last but not the least, some very common biochemically relevant ionic compounds (e.g. Monoammonium phosphate) show time-crystal behaviour, such crystal surrounded in hydrophobic (inside) transparent micelle (possibly overall amphiphilic) in presence of a biological or external optoelectronic field can drastically alter standing waves-system in-vivo, possibly in an unexpected manner (note constructive and destructive interference are only half/quarter wavelengths apart). A nano-phased array of optical system can modify such response quite dramatically. (such time crystal can be designed to keep working on harnessing nonequilibrium biochemical environment as well)

There must be some problem with the pH meter then.. U should show it to a technician so that it can be fixed.

@ Chandra, please have a look of the attached file.

Can have a look - on the attached manuscripts

Please check the following link, I hope this can help:

I've made a synthesis in French a few months ago. Hope it will help.

I highly agree with the opinion reported by Frank T. Edelmann

Regards

some the hottest topics right now in organic chemistry research :

Synthesis of Chemical lead compounds to control COID-19

The virus uses several protease enzymes, they are particularity sensitive to pH changes .

Mostly pH is affected.

Dear all, hope the attached basics books will be helpfull. My Regards

Dear Oussama,

From this picture I cannot state with certainty if it is the same structure (= the same molecule with the same crystal packing) or not, because the representation is different. The coordinates of the atoms are chosen differently with respect to the origin in A and B. You can probably shift your atoms in the unit cell so that the two structures look more similar.

From the unit cell it seems the same structure: the difference in volume is "negligible" and the different reported Z, Z' is likely due to a different definition of the moiety formula or sum formula.

But, in principle, the unit cell is not enough to decide if it's the same structure. As suggested, you can compare the simulated powder patterns. I also suggest to carefully compare the crystal packing by analyzing the intermolecular contacts and examining a bigger packing range (like for example 2x2x2 unit cells). Some programs also allow to overlay two crystal structures, to visually compare them.

In any case, you can most probably publish your structure along with the solvated form, with more focus on this latter, as it is new. Compare if there are real differences with the literature structure, for example, were they measured at the same temperature? Any conformational differences? I suggest you adopt the same atom labelling names and the most similar setting to the published structure, in order to facilitate the comparison both for you and for the readers.

Best wishes,

Arianna

Joseph Tham, thanks for a thought provoking question. I think we should tolerate and respect beliefs and ideas that are not considered scientific. Our intolerance of such beliefs and ideas could be the result of a lack of understanding of the science behind them. We should therefore subject them to rigorous testing using the scientific method. A practical example is the fact that the World Health Organization has not dismissed out of hand the herbal remedy from Madagascar that is claimed to prevent illness from COVID-19. Instead the remedy is going to be tested using established scientific principles. The null hypothesis can then be rejected or accepted. This is how Indigenous Knowledge Systems contribute to scientific advancement.

Sometimes it is just but a misconception and a result of peer pressure. Such students require alot of motivation for a positive attitude to the subject.

Dear , in such redox reactions, it is not possible that all reagents are being reduced. Oxidation and reduction must always take place simultaneously. In this case., the metallic copper is oxidized by iron(III) chloride, i.e. FeCl₃ is the oxidizing agent which is itself being reduced to Fe²⁺. On the other hand, you start with metallic copper (Cu⁰), which is the reducing agent. During the reaction, Cu⁰ is oxidized to Cu²⁺, i.e. the copper foil slowly dissolves.

Hi there,

Additionally to Fache Axel answer please check the paper: A Kinetic Study of OH Radical Reactions with Methane and Perdeuterated Methane by James R. Dunlop & Frank P. Tully.

Best

Herbst, J. F., and J. J. Croat. "Neodymium-iron-boron permanent magnets." Journal of magnetism and magnetic materials 100, no. 1-3 (1991): 57-78.

Hi Saeed,

If you have the top view and side view of the MXene, with dimensions present on the figure, you can make the system. The top view and side view of relaxed MXene systems should be available online.

Also, if you have the atomic coordinates for a unit cell, you can use the lattice vectors to make large supercells.

I have attached another book. It is not possible to attached them together.

Hi Alexxandra Jane Ty

The relationship between rates of lipid oxidation and moisture is complex. The amount of water, the water activity and the state of water in a food, along with other factors, must all be considered.

For most fresh or tissue foods that have moisture contents between 60 - 95% have a water activity very close to 1.T he mode of deterioration at this water activity is generally microbial or enzymatic in nature. Direct lipid oxidation (i.e. not enzyme-mediated) is not an important source of deterioration at this high water activity since other modes of degradation will deteriorate the food first.

Concentration, freezing, and drying are mechanisms by which the water activity of food can be reduced. Such processes may bring the food into the intermediate moisture or low-moisture region where direct lipid oxidation becomes a more important mode of degradation. Also, during dehydration, free radicals can be formed which accelerates lipid oxidation. Freezing can also lead to the acceleration of lipid oxidation rates through the concentration of substrates and catalysts in the unfrozen portion of the system.

On the other hand, Chou et al. (1973) found that water activity primarily affects matrix swelling and thus substrate/reaction site availability as well as catalyst mobility.

Hereinbelow the tow common theories related to the relationship between water activity/content and lipid oxidation are briefly discussed:

Unlike most aqueous chemical reactions, the rate of lipid oxidation that takes place in the oil phase is observed to increase as water activity is decreased below the monolayer (i.e. water molecules that are bound tightly to the food surface). This can be explained by considering the role of water in this reaction. It has been suggested that the monolayer of water—or rather, the water saturation of polar groups in lipids—is necessary to cover the surface of the lipid, preventing it from direct exposure to air. This monolayer is essentially “bound” water with limited mobility and is assumed to not participate in chemical reactions. Several studies have found that a variety of foods are most stable to lipid oxidation at a relative humidity or aw consistent with the monolayer.

On the other hand, water can form a hydration sphere around metal catalysts such as Cu, Fe, Co, and Cd. In the dry state, the metal catalysts are most active. As water activity increases, the metals may hydrate which may reduce their catalytic action thus slowing the rate of lipid oxidation.

This monolayer theory, however, cannot be applied universally.

According to the glass transition theory, one important function of water is its ability to act as a plasticizing agent. The plasticization of a matrix involves swelling of the polymer matrix when moisture is increased. The resulting increase in free volume might allow for faster diffusion of substrates in the aqueous phase which may lead to faster reaction rates. Plasticization may also increase the contact of the absorbed aqueous phase with the lipid phase. The number of catalytic sites increases such that the rate of lipid oxidation increases.

The above discussion shows that water plays both protective and prooxidative roles in lipid oxidation. In some foods at low aw near the monolayer moisture content, water is protective, presumably because it provides a barrier between the lipid and oxygen.

While the classic food stability map proposed by Labuza et al. (1972) shows lipid oxidation having a U-shaped relationship to aw, no U-shape was also observed; lipid oxidation actually slowed as aw increased as the case of freeze-dried food.

Overall, monolayer and glass transition concepts might not effectively predict lipid oxidation reactions in some foods if oxidation is primarily occurring in the lipid phase and thus would not be significantly impacted by water and the physical state of proteins and carbohydrates. On the other hand, water can play a major role in lipid oxidation chemistry if reactions are primarily promoted by water-soluble prooxidants such as metals. Unfortunately, the causes of lipid oxidation in low-moisture foods are poorly understood, which could be why measurements of water activity, monolayers, and glass transitions do not consistently predict lipid oxidation kinetics.

Sources:

https://scholarworks.umass.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1159&context=dissertations_2

Thats a very good idea to unite and make joint efforts to defeat the pandemic the world is suffering.

Flow measurement can be performed with different methods. Accuracy of reading may depend on different factors like samples water etc.

The Sarbecoviruses (SARS and SARS-related beta coronaviruses) are a faily diverse clade of coronaviruses. Merbecoviruses (MERS and MERS-related beta coronaviruses) are another clade with similar diversity. The SARS-CoV-1 and SARS-CoV-2 sarbecoviruses are quite distant from each other.

It may be due to aggregation, use stabilizing agents to reduce aggregation.

I see some very good answers - we do the estimation by measuring the change in thermal conductivity of the space. The measurement can be more meaningful if you know the composition of the mineral deposit. The thermal conductivity of common water system scales is known. If the accumulation is, in fact, deposited, not grown in place - then the thermal conductivity model would be more relevant within repeated accumulation/settling of solids in that location.

Thermal conductivity is an accurate means of measuring the relative thickness but the results are more material with repeated measures or an accurate knowledge of the physical and chemical composition of the matter of interest.

Hi Annie, you can try to search the CIF file you need at COD (crystallographic open database - http://www.crystallography.net/cod/) or Materials Project ( https://materialsproject.org/) database. They are free of charge.

You have answered your own question. Proper chromatography methods require detection methods which are applicable to the samples under analysis. You may want to review the types of instruments, detectors, columns and materials available at your school before deciding on a final approach. Have someone in the school's analytical instrument lab assist you.

For HPLC samples with weak or no chromaphore, you will need to use a detector that does not rely on wavelength based light absorbance such as an RID, ELSD, CAD or MS, to name a few. Put a little time into researching this basic question so you will better understand the uses and limitations of these methods and detectors. I often suggest my students start with a keyword search on the web (GOOGLE or BING) to find examples and articles to review. This is one of the best ways to learn. Once you have familiarized yourself with the basics, be sure to ask your teacher for help in setting up and running some example methods.

BTW: You may also be able to derivatize some of your samples and use GC/FID or GC/MSD as an alternative to HPLC (only if the samples are appropriate).

I read that after leaching of oxidized zinc concentrates with sulfuric acid, the resulting solution is purified from harmful impurities like iron, copper, cobalt, nickel. And with a weakly acidic medium, pH = 5.2–5.3 iron ions are practically precipitated by the formation of hydroxides.

hi Spvnd Sumalatha ,

If a person is good in mathematics and has command over it, that means he has good logic aptitude and grasping ability. If now he want to do research in Fluid mechanics of course he can. He should start with reading the basic physics books and gradually increase the level to engineering fluid mechanics. Which, at this stage, should be a matter of not more than 6 focused months. after that he will be able to do like masters. Do not run behind paper publication from the start it will a by product of your focused learning and problem solving.

Dear Dr Gilson

I am ready to help if I could and be grateful to do something due to make progress!

I think many valuable media and journals could be useful for you such as:

https://www.nature.com/subjects/environmental-chemistry

https://www.wiley.com/en-us/Environmental+Chemistry+at+a+Glance-p-9781405135320

https://www.springer.com/journal/10311

Hydazine hydrate solution in water is basic (pH=11) but the solution of Hydrazinesulfate in water is acidic (pH = 3). So to get the hydrazine hydrate from hydrazine sulfate , the pH of the hydrazine sulfate solution has to be tuned to pH= 11.

Here the procedure:

Dissolve the Hydrazinesulfate in water ( 1 g in 30 ml), check the pH (then add Ambersep 900 hydroxide from resin (or any other OH from resins) and adjust its pH to 11. Filter the solution to obtain Hydrazine hydrate.

I have used this procedure recently, it works very well.

Hi,

as mentioned, it is indeed necessary to provide a more specific question in this case. Depending on the machines available in your lab it could be possible to perform an analysis more than another. Of course some basic chemicals are in every lab, but to avoid misleading you it could be better to receive more information about the type of research you want to carry.

Please have a look at the following link:

https://www.researchgate.net/publication/303898318_PHYTOCHEMICAL_TECHNIQUES_-_A_REVIEW

Best regards

Mostly adipic acid, manufactured from hexane, and also 1,6 Hexane Diamine, also made from hexane. Or Caprolactam made from hexane.

see below link

https://www.techrepublic.com/blog/five-apps/five-tips-for-extending-lithium-ion-battery-life/

It looks like neither the journal nor EndNote provide a style file, thus you will have to edit an existing style (perhaps ACS). If you have EndNote on your computer (not the plug-in but the stand alone program), go to Edit/Output Style/Edit "ACS"/Bibliography/Templates. Edit the journal article template, then save the edited style with a new name. When you reopen Word, you should see it when you "Select another style".

Dont worry. Dr Kafferlein. We are all here for discussion. That's no wrong or right answers. Thank you so much for your contribution.

Please observe what happens when CH₂CL₂ , taken in a separating funnel, is shaken with a little bit of water and then allow the mixture to get separated in to two layers.

Collect the organic layer, and observe the layer keenly and add anhydrous Mg(SO4)₂ to the organic layer. The layer on becoming dry, should turn into a transparent liquid after becoming dry.

Now, the following would be my comments.

(a) Absorbed moisture can impart turbidity to organic solvents. This is specially so with low-boiling liquids like CH2CL2 and diethyl ether.

(b) Anhydrous solvents normally have a great tendency towards absorbing moisture, when kept exposed to a moist environment.

(c) Please do keep in mind that chlorinated hydrocarbons are normally avoided due to their toxicity.

You can also find more in this link:

Daniel Jackson yes, you are right, you need made serial dilutions from the primary solution. I recomend you this video to understand the method.

https://www.youtube.com/watch?v=MCrNjHcfcpY

Regards.

Hello Mr. Ulrich Deiters

My solvent is water.

I hope you feel well today. I will write what I understand from your equation. In really adsorption presence is separation method or transfer containment from liquid or gas phase to the solid phase. Therefore, there are products waste as solid can control it for disposal or reuse. All treatment processes need an energy source for work but adsorption does not want that. The low cost of operation and the initial cost of adsorption is the advantage. On the other hand, we use the adsorption process for removal of the low initial concentration of the heavy metal that can't be removed from water by precipitation. Today, the researcher tries to find now mater that has high adsorption capacity at the same time made this material from waste ( the name of adsorbent is super-adsorbent ) such as metal-organic network , nanoparticle, polymer, and hydrogel.

You might be able to couple the rhodamine carboxyl to an alginate hydroxyl with a water soluble diimide coupling reagent.

Or use a different dye....

You may not want to use the following advice if you are weighing hazardous substances: don't wear gloves. They are a big source of static. Check with the lab head whether this is permissible if you want to try it. Wash your hands afterwards.

Otherwise, minimize static by avoiding a lot of motion of the solid in its container. In other words, avoid shaking or tapping the container. Use metal spatulas, not plastic ones. If you are not weighing the solid directly into the final container, use glassine weighing paper rather than a weighing boat. Use the smallest feasible piece of weighing paper, not necessarily a whole one.

Thank you gentlemen for your assistance, really appreciate it.

Hi Ryan,

I think that B is the correct answer. Usually Mixing solvents with statement 1:1 means equivolume mixing of components, (1+1=2volumes diluted finally x2) which finally yields halved concentrations of constituents. This should be premixed if used as Hplc mobile phase and degased, and pumped through special pH basic resistant column matrix.

Spectrometric identification of organic compounds I Robert M Silverstain

Yes, if electron withdrawing groups are prsent in near or conjugation to phosphrus, then n then only chance for more labile oxidation. but any phosphites are highly undergoes to oxidation so inert atmosphere is needed.

thank you

Ender Araujo

I have experience with r-candy propellants, and its not very dangerous as other solid propellants (for example APCP). If you apply the basic safety procedures you will be very safe (lab coats, safety googles, masks etc). If you make the propellant by heating method, then you must be carefull with the burners, because when you put the propellant in the mold through casting method, its very important to ensure that the propellant will not fall on the burner by mistake. Because you have to make the propellant with students, I will recommend to you to mix well the KNO3 with sugar as raw materials and do not use the heating method.

Also, you have to consider that these propellants are not easy to ignite them, so be sure that you will ignite the propellant from far, using ignition wires, not with lighter.

If you want to increase the burning rate, you can decrease the KNO3 particle size or you can add a small quantity of Fe2O3 red iron oxide as catalyst. But if you do that, you have to keep in mind that it will be more dangerous.

It is very good to learn to your students the significance of safety.

Dear Dr. Haider Abdulkareem Al-Mashhdani,

in a previous question relating to this topic here in ResearchGate, Dr. @Angel Cuesta, gave the following, very clear, explanation.

The Tafel slope simply tells you how much you have to increase the overpotential to increase the reaction rate by a factor ten. This will be determined by the magnitude of the change in the activation energy for a given increase in overpotential (when you change your potential 1 V, the Gibbs energy of the process will change by 1 eV per electron transferred, but the activation energy will only change by a fraction of this, and this fraction determines the Tafel slope). In a reaction involving only one step with one electron transfer, the Tafel slope will be determined by the symmetry factor, which is usually 0.5 (corresponding to a Tafel slope of 120 mV). In a more complex reaction involving several steps and several electron transfers, the Tafel slope will be determined by the rate-determining step and by the number and nature (i.e., involving an electron transfer or not) of the preceding steps. So, essentially, from the Tafel slope you can deduce whether your rate-determining step involves an electron transfer or not, as well as the number of electrochemical (involving an electron transfer) and chemical (not involving an electron transfer) steps that precede it. If you propose a reaction mechanism, you can calculate what the corresponding Tafel slope should be and, if it does not coincide with the experimental one, the mechanism cannot be correct.

For more details, you can have also a look at the following notes:

-Tafel Plot and Evans Diagram

By Palm Sens

Available at: https://www.palmsenscorrosion.com/knowledgebase/tafel-plot-and-evans-diagram/

- Quantitative Corrosion Theory

By Gamry

Available at: https://www.gamry.com/Framework%20Help/HTML5%20-%20Tripane%20-%20Audience%20A/Content/DC/Introduction_to_DC_Corrosion/Quantitative%20Corrosion%20Theory.htm

Best regards, Pierluigi Traverso

Hi

How do i separate powder it contains sodium bicarbonate,tartaric acid and citric acid by HPLC or only organic acid ?

SiF4 gas will appear and take in consideration that SiF4 is toxic and corrosive. In moist air it fumes, whereby it is easily hydrolyzed to give H2SiF6 and SiO2. However, in my opinion the most toxic / hazardous substance in this system is certainly HF. Utmost care must be exercised when working with HF, especially if it is a concentrated solution (40%) or even anhydrous. It easily penetrates the skin and can lead to serious injuries

You're welcome. I just noted a typing error in my answer. 0.786 g AgNO3 is of course 4.63 mmole, not 6.63 mmole. It must be the same as the mmole amount of Ag.

Ashok - H2O2 is used to remove organic matter from sediments - not carbonates. If you are trying to remove carbonates, but wish to leave any clay minerals unaffected, you should use a buffered sodium acetate/acetic acid solution (pH 5.3). If you aren't concerned about the clay minerals, dilute HCl would be fine. E-mail me if you would like the method.

Saida, If you have a look at a Dieke diagram it'll be apparent to you that the energy states of La are well separated (gs and es) way above its bandgap so no emission line will fall in the visible region. And La doesn't have 4f electrons as the other lanthanide ions do. Also, other emissive lanthanide ions which are often used as emitters, have energy levels that are separated by energies falling in the visible range. However, due to the inner shell configuration of these 4f ions, it's very unlikely that you can directly excite a 4f-4f transition in these- so you'll see little-to-no emission intensity. However, if you have La in the material it can absorb the incident energy and efficiently transfer it to the emitting lanthanide ion in an indirect way. But this energy transfer is strong enough that it populates the emissive states of your lanthanide activator and you'll see the fluorescence occurring from them. That's why you see an increase in luminescence efficiency in the presence of La.

I agree with Neeraj K. Sethiaya

Just the the second method, you cant use methanol to isolate the alkaloids,

you most make two immesible layers , like chloroform and polar solvet,

Best regards for all

Souad Djellali Neeraj K. Sethiya Alok Nahata Souad Djellali Jack Silver

Working with C2-Ceramide it obviously had an effect on the treated cells in our publication ( ). Therefore, I think it is increasing solubility and subsequently effectivity of the compound. For the preparation of a C2-CER BSA mixture you can follow the instructions by ENZO. It worked well for me.

Best

Konstantin

I also recommend

Ellis, KJ et al. Methods in Enzymoloigy, Vol. 87.

and

Dawson, RMC et al. In: Data for Biochemical Research. Chapter 20.

Yes Mr.

Actually, when we try for the annealing of potassium niobate, we suffer from those cracks on the tube. The niobium gets reacted with Si and forms Niobium Silicate. Those cracks are at inner surface of the tube. And cracks get propagated and unfortunately that tube get damaged.

I agree with C.A. (Kees) Kan

Dear Gabris Mahamid, Such a database aggregated and sorted at this stage is being developed. It has not been tested and therefore cannot be seen. The development is of large companies such as: Web of Science, Scopus, Google Scholar and Google Academia, Microsoft Academic, Semantic Scholar and others. There is only a partial finding at this stage of these data companies on specific topics in specific areas. Wishing you success in research. Emil Yankov

Study of diseases and the pharmacological potential and mode of action of drugs

Dear all, some journal use the experimental details in a separate file with a specific DOI. It is named 'Supplement file'. It is mentionned in the first page mother file. Generally it is free downloadable. My Regards

Thanks for your message Priya Dharshana.

I am looking for a sample not for a template.

Hi;

The electrosynthesis provides a better environment for the generation of reactive species by dissociation or bond forming processes. The reactive carbon species are used in various synthetic transformations, essentially C-C bond formations. Oxidation and reduction of functional groups are also important reactions in organic synthesis. A major advantage of electrosynthesis is the reduced formation of side products.

With my best regards

A magazine is definitely not the same as a Journal. Magazines normally carry popular articles, not original work. A Scientific Journal publishes original scientific work not published elsewhere. 'Letters' or 'Notes' are of shorter length. It may include a comment on an already published recent paper by the author or someone else. Normally, Editor takes decisions on 'Letters' and 'Notes'. Seldom are they are sent to reviewers.They get published quickly. A full length paper in a reputed Journal has to undergo peer review process and may take up to an year or so to get published.

Hello, same topic discussed here

Good Luck!

https://www.researchgate.net/post/Is_there_a_protocol_for_a_second_immunostaining_of_organotypic_hippocampal_slices

Jingjing Xue

There have been a lot of initiatives to include active learning exercises in both lecture and lab. Many have observed good results in information retention and elimination of misconceptions. I have observed some of these results firsthand, and active learning is something I think is quite valuable. Here are a few resources, but there's lots of info out there:

For curriculum, I have noticed a shift towards an "atoms first" approach, but I haven't seen anything conclusive on its effectiveness. My feeling is that it works well for some students, not for others (just like any approach). I have yet to see any good methods on stoichiometry excepting certain teachers who have a knack for explaining it well.

This article suggests focusing on training teachers and developing innovating learning material:

This blog suggests directing chemistry towards things people will actually use and encounter (cooking for example):

The American Chemical Society has a small guidebook on what should be explored:

(See also attached pdf)

I hope the resources will help you.

The lightest elements (mainly hydrogen and helium and in trace amounts lithium and beryllium) were formed about 100 seconds after Big Bang through the Big Bang nucleosynthesis (this process lasted up to 20 minutes after Big Bang).

After the formation of stars new elements, from helium to iron, are produced in stellar nucleosynthesis (thermonuclear fusion: CNO cycle, proton–proton chain reaction and triple-alpha process) during stellar evolution.

Elements higher than iron are produced in supernovae through the r-process and s-process.

A very good book about this and generally about properties of stellar interiors and the structure and evolution of stars is: "The Physics of Stars" A. C. Phillips.

About the nuclear physics of stars, you can see also a book of Christian Iliadis "Nuclear Physics of Stars".

i am work about antibacterial activity of material and synthesis of nanomaterial

Store the stocks in the fridge, i.e. cool and dark, and they should last for months. What tends to happen is that they slowly concentrate due to evaporation. So use good containers. The more dilute solutions are more stable in acid. Even 1 mg/L is quite concentrated beside the solutions used to calibrate ICP-MS so it should be OK for a few days. Beyond that rely on testing for yourself.

Can you tell if it exploded (pressure build up) or imploded (sealed while warm and bottle was flawed)?

Only concentrated KOH is dangerous (Caustic soda). But solutions of 10 - 15 % (that is around 2 mol/l) are medically used for topical application.

I can find safety data for a KOH solution of 0.1 M at a Sigma-Aldrich site

https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=NL&language=EN-generic&productNumber=417661&brand=SIGALD&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Fterm%3DKOH*%26interface%3DAll%26N%3D0%2B8653199%26mode%3Dmode%2520matchpartialmax%26lang%3Den%26region%3DNL%26focus%3Dproduct

NO STATEMENT for special ventilation is given for 0.1 M KOH

But for 0.001 M, their could be no harm at all (except do not swallow ..). No need for special ventialtion or fume hood.

What about try acid digestion?. Normally people to determine the metals by ICP-MS using HCl:H2SO4: HClO4.

You can measure the stoichiometry of a sample using X-ray photoelectron spectroscopy, although XPS is normally very surface sensitive so there may be some difference between the measured st. and the bulk of the QD depending how small it is.

Drotaverine is sparingly soluble in water. In DMF/PBS 1:5, the solubility is 0.16 mg/mL. See https://www.caymanchem.com/pdfs/20944.pdf

Dear Sammy,

Prof. A. Tikhonov already nicely summarised the most important issues concerning up-conversion. As far as phosphors are concerned, there are a couple of materials that can show rather efficient NIR to VIS up-conversion at moderate irradiation levels. These are: NaGdF4:Er,Yb; Gd2O2S:Er,Yb; BaY2F8:Er,Yb and YOCl:ErYb.

All of these materials make us of the mechanism of Sensitised Energy Transfer Up-conversion (S-ETU), while Yb3+ is the sensitiser and Er3+ the green or red emitter. Important is that the host material has solely low phonon energies, otherwise the process is easily quenched by electron-phonon coupling. Good luck!

Thomas

When we want to trap hydrogen fluoride on a filter in order to estimate its concentration in the atmosphere we use filters soaked with sodium carbonate. I think you could try to adapt this method to your issue. You can see an exmple of the use of this method here: