Biomaterials - Science topic

"repel" was your term. the differecne is yours to establish.

I am looking for information on NQR measurements of protein and amino acid crystals.

You may want to check: C. M. Queiroz, S. Agathopoulos, J. R. Frade, M. H. V. Fernandes, "Network connectivity and bio-mineralization of 0.45SiO₈-(0.45-x)MgO-xK₂O-0.1(3CaO⋅P₂O₅) glasses", Materials Science Forum, Vols. 455-456, 2004, 383-387.

Nanoindentation is a separate testing procedure that is often used in conjunction with Atomic Force Microscopy (AFM). It is used to measure properties at the nanoscale, such as Young's modulus, hardness, stiffness, and load vs. depth and load vs. hardness. Other properties can also be measured using nanoindentation, depending on the specific application. In India, there are several institutions that offer nanoindentation services. These include the Indian Institute of Technology (IIT) Delhi, IIT Bombay, IIT Madras, IIT Kanpur, IIT Hyderabad, and the National Institute of Technology (NIT) Surat. Additionally, there are several private companies that offer nanoindentation services, such as NanoTest India, NanoTest Solutions, and NanoTest Technologies. If you are having difficulty finding a nanoindentation service provider, it is possible that the machine is under maintenance or the operator is not available. In this case, it is best to contact the service provider directly to inquire about the availability of the machine and the operator.

i guess you need to mail the company to provide all these details.

they should be happy to share if there is any concrete data on that matter

Respected Sir,

For your reference the book is attached herewith.

Hope this may be useful.

Dear Noor Ul Ain, yes and in addition to other parameters, quaternization enhanced antibacterial activity. Please have a look at the following documents. My Regards

10.1039/9781788012638-00001

10.47577/technium.v2i7.2009

You can read this article. Maybe it can help you!

Dear all, following a list of interesting books. My Regards

- Fundamentals of Materials Science and Engineering: An Integrated Approach, William D. Callister, David G. Rethwisch, 5th Edt (2015).

- Materials Science and Engineering: An Introduction, 10e WileyPLUS NextGen Card with Loose-Leaf Print Companion Set, Callister Jr., William D., Rethwisch, David G. 10th Edt (2018).

- The Science and Engineering of Materials, Donald R. Askeland, Wendelin J. Wright. 7th Edt (2014).

- Materials Science and Engineering: A First Course, V. Raghavan, (2004).

- Foundations of Materials Science and Engineering, Willaim Smith, Javed Hashemi, 6th Edt (2019).

Thank you Monika Spasovová for the correction.

I also didn't know much about these conferences. Someone shared this link earlier, so I copied it here.

I have deleted my comment now.

STEPS FOR PREPARATION OF BIOLOGICAL SPECIMEN

1. FIXING IT IN BUFFERED ALDEHYDE FOR 3 HOURS : Buffered Aldehyde for SEM consists of 2.5 % glutaraldehyde in phosphate buffer as follows:

• 40 ml of D. water.

• 10 ml of 25% glutaraldehyde.

• 50 ml of 0.2 M Buffer stock solution at 7.2 pH.

0.2 M BUFFER STOCK SOLUTION AT 7.2 PH CONSISTS OF:

• 91.6 ml of Sodium cacodylate solution (4.28 g/100 mL distilled water),

• 8.4 ml of 0.2 N HCl (1.7 mL concentrated HCl/100 mL distilled water)

2. DRAIN GLUTARALDEHYDE AND RINSE 3 TIMES IN Sodium cacodylate solution BUFFER EACH FOR 5 MIN (3 × 5 = 15 MIN)

3. POST FIXING IT IN OSMIUM TETROXIDE FOR 1 HOUR:

• 2OsO4 is used as post-fixing after aldehyde fixation to prepare a 2% aqueous solution (1 g of OsO4 in 50 ml D. water) a working fixative is prepared just before use by mixing equal parts of 2% aqueous stock OsO4solution with equal parts of 0.2M Buffer stock solution.

4. RINSE IN DISTILLED WATER.

5. DEHYDRATE THE SPECIMEN USING A GRADED ETHANOL SERIES 25%, 50%, 75%, 90% AND TWO 100% EACH FOR 10 MIN. (5 × 10 = 50 MIN).

6. DRYING USING A CRITICAL POINT DRYER DEVICE.

7. REMOVE THE SPECIMEN, MOUNT ON SPECIMEN STABS, COAT WITH GOLD, AND VIEW IN SEM

8. SEM AT 20 keV AND T1 GARIN SIZE 40 WORK DISTANCE 15 mm.

You can get porous nanofibers structures through increasing the humidity of the environment and many other factors pls check the following links:

Dear Noor Ul Ain, please have a look at the following recent review document and the references therein. My Regards

The best method is to centrifuge at low temperature, then extract the top phase. As only should use glass tubes, so you should centrifuge at low temperature rather than freezing the samples, as the glass tubes will be broken!

Yousof Farrag for wound healing purpose

Dear Sir:

We are still far away from the prediction of the steps found in the thermodynamic irreversibility of protein adsorption. However we can do a lot from the side of analysis in the determination of protein adsorption hysteresis [1-3].

With best regards

Herbert Jennissen

(Email: hp.jennissen@uni-due.de)

References

[1] Dohle,D. S., Zumbrink, T., Meißner, M., & Jennissen, H. P. (2020) Protein Adsorption Hysteresis and Transient States of Fibrinogen and BMP-2 as Model Mechanisms for Proteome Binding to Implants. Curr. Dir. Biomed. Engineer, 6, 1-4 (https://doi.org/10.1515/cdbme-2020-3046).

[2] Jennissen,H.P. (1985) Protein Adsorption Hysteresis. In "Surface and Interfacial Aspects of Biomedical Polymers" Vol.2, Protein Adsorption (Andrade,J.D., ed), pp. 295-320. Plenum Press, New York.

[3] Jennissen, H. P. (2021) Protein Adsorbate Biohybrids and Sequential Hystallosteric Protein Adsorption. Curr. Dir. Biomed. Engineer,7, 731-734 (doi.org/10.1515/cdbme-2021-2187).

يحتاج الى مختص في مجال الجلدية

The moisture diffusivity of any material is a function of temperature and hence the drying kinetics is a complex phenomenon. If we study the drying curves for convective drying at different temperatures we can observe that the drying time is highly variable as the temperature changed, although the kinetic profiles for the wet basis moisture content for all temperatures are relatively similar.

The moisture diffusion and convective mass transfer are to an extend modulated by the heat transfer kinetics of the system and hence would require extensive modelling.

You may find an appropriate article in the link below.

Density decrease as I found many studies

Hi Dinesh

Strain controlled fatigue testing is important to study the behaviour of components undergoing either mechanically or thermally induced cyclic plastic strains that cause failure within fewer cycles (<10^5) than high cycle fatigue (>10^5-10^6 cycles).

The testing conditions are usually determined by the specific application you are considering. Doing this preliminary investigation will allow you to get more meaningful and useful results from the strain controlled tests.

So I would recommend to try to collect some initial indicative data to better plan the test conditions (temperature, R, frequency, strain levels). If the components (or an older version of the components) are already in service you can get some good indications by applying some strain gauges and thermocouples to the parts to understand what sort of strains they undergo and at what temperatures. If the components are still in the design phase then you will need to carry out some hand calculations or run some FEA analyses to get a feeling of what strain the parts will experience once in service.

Having said this, in terms of strain levels you can consider that you enter within the high cycle fatigue range when the part undergo loads that generate stresses below half of the yield strength of the material i.e. 0.2% so you want to stay above this value. In general you could run tests at strain level within 0.2% and 20-40%. It depends also by the material and test temperature. Then with the Coffin-Manson equation you can relate cycles to plastic strains.

To determine the values of temperature, frequency and R for your tests, as previously mentioned, it would be better if you use values close to your actual application to collect more reliable and useful data.

It all depends on the cell type and biomaterial (soft or hard) which you use. Cells grow slowly on softer tissue compared to hard or plastic.

Also check https://www.hindawi.com/journals/ijps/2018/6387826/

yes;

may not go to a better universities

I recommend to use ANN(artificial n euron network ) combination to RSm(response surface methodology )

Bilirubin, Saffron Dye, Luciferin, Aequorin, etc.

Hi. I hope the following article could help you:

Dear Miller,

Wire is made of what element? is it tungsten?

Just check with Digi-Key Electronics and Arrow Electronics(Thief River Falls, Minnesota, United States). Perhaps you can contact here at phone no. 541-323-3228, customer services- 00 1 218-681-7979.

If tungsten, contact yolo in china.

Ashish

Dear Maria Apriliani Gani,

These may be addition of impurities, high temperature and environmental conditions can reduce the formation of carbonates.

Bone mineral is not pure hydroxyapatite. The small, plate-shaped (20–50 nm long, 15 nm wide, and 2–5 nm thick) apatite crystals contain impurities, most notably carbonate in place of the phosphate groups. The concentration of carbonate (4–6%) makes bone mineral similar to a carbonate apatite known as dahllite. Other substitutions are potassium, magnesium, strontium, and sodium in place of the calcium ions, and chloride and fluoride in place of the hydroxyl groups.These impurities can reduce the crystallinity of the apatite , and, in doing so, may alter certain properties such as solubility. The solubility of bone mineral is critical for mineral homeostasis and bone adaptation.

Carbonate substitution in apatite each control the crystal’s perfection and crystallite domain size, affecting material properties, in different environmental conditions. High temperature substitution methods indicating a higher energy barrier for the formation of carbonate.

Ashish

Compared to various living organisms characterized by a much lower level of organization and body structure, the human body has limited regenerative abilities. However, along with technological advances, in medicine, genetics, microbiological tests, etc., the possibilities of transplanting various organs, limbs, growing specific types of tissues and rebuilding certain parts of the human body are gradually increasing. One of the most difficult and perhaps impossible to implement in the future is the rebuilding of the central nervous system, including the human brain. Similarly, it will be extremely difficult in the future to build artificial awareness in artificial neural network systems as a continuation of the progress made in the development of artificial intelligence.

Best regards,

Dariusz Prokopowicz

Hi Taufiq Ahmad . From literature, it looks like the BCA assay works only with secondary amines. As the secondary amines form a colored chelate complex with cupric ions (Cu2+) in an alkaline environment and form Cuprous (Cu+) ions. The Cuprous ions form a complex with the BCA assay.

In experience I have found a linear response of BCA assay with Primary amines too. I do not know what the exact mechanism is for that. Did you find it out?

Nabodita Sinha thanks for your opinion. Since I detected the presence of cells on the biomaterial in MTT assay and SEM analysis, it was very interesting that the cells were not visible in the H&E staining of the same sample. When I made a literature review, it was suggested that it should be kept in the fixation solution for at least 4 hours, but I kept it for 1 hour. Therefore, I think that the cells do not hold in this period and leave the environment in washing with dPBS. I will try the fixation time again for a minimum of 4 hours and a maximum of 1 day.

I hope this is the problem.

I suggest that you read the following papers where we described different degradation processes on PCL samples (films, fibers, and fabrics)

André Rangel, Tuan Ngoc Nguyen, Christophe Egles, Véronique Migonney, Different real-time degradation scenarios of functionalized Poly(ε-caprolactone) for biomedical applications, J. Appl.Poly. Sci. 2021,

Long-term Hydrolytic Degradation Study of Polycaprolactone Films and Fibers Grafted with Poly(sodium styrene sulfonate) : Mechanism Study and Cell Response, Biointerphases 2020;15, 061006, doi: 10.1116/6.0000429

Adapting mechanical characterization of a biodegradable polymer to physiological approach of Anterior Cruciate Ligament functions, TN Nguyen, A Rangel, V Migonney, IRBM 2020 ; https://doi.org/10.1016/j.irbm.2020.10.002

NT Nguyen, A Rangel, V Migonney, Kinetic and degradation reactions of poly (sodium 4-styrene sulfonate) grafting “from” ozonized poly (ɛ-caprolactone) surfaces, Polymer Degradation and Stability 2020; (176), 109154;

Dear Vipul Patel , are you sure hydrogels exist in liquid form? If yes, please help me with the procedure to change their semi-solid state to liquid without compromising other properties.

Thank you very much Nabodita Sinha I would also like to know more about the stress fiber alterations, Nuclear blebbing and cortical ring formations.

Dear Dr. Akram Jassim Jawad ,

in addition to the answer of Dr. Abdelkader BOUAZIZ ,

-a Silicone liner provides high stability and good adhesion if your limb has a lot of soft-tissue. ...

-Polyurethane has a unique ability to flow away from high pressure. ...

-copolymer is soft, cushiony and highly elastic, offering good protection for amputees with sensitive skin and/or lower activity levels.

For more details, please see at:

- What materials are used to manufacture prosthetic liners?

Available at: https://amputeestore.com/pages/what-materials-are-used-to-manufacture-prosthetic-liners

- All About Prosthetic Liners: Part 2 Choosing the best material.

Available at: https://amputeestore.com/blogs/amputee-life/prosthetic-liners-silicone-gel-differences

Best regards, Pierluigi Traverso.

Dear Anish Hiresha Verma,

Stem cell transplants commonly are used to treat leukemia and lymphoma, cancers that affect the blood and lymphatic system. It also can help patients recover from or better tolerate cancer treatment. Nano sized materials have particular advantages for cancer treatment with distinct features relative to low molecular weight drugs. These properties are being effectively exploited for improved delivery of chemotherapeutic drugs resulting in both enhanced anticancer activity and reduced systemic toxicity.

When we apply a magnetic field externally, these nanoparticles starts spining. Nanoparticles must attach to the surfaces of cancer cells, by which it induces the spinning to mechanically destroy the cell membranes. The drug molecules carried by nanoparticle are released in the extracellular matrix and diffuse throughout the tumor tissue. The particles carry surface ligands to facilitate active targeting of particles to receptors present on target cell or tissue.

Refer

1. https://www.nature.com/articles/nature10694

2.

Ashish

Dear Staish Kumar,

Mixing calcium chloride and potassium dihydrogen phosphate with sodium chloride could be the solution for your complete dissolution. pH can be adjusted. Potentiostat/potentiometer can be used if one wish to see the antibacterial and fluid effect if any.

The general understanding is the solubility of hydroxyapatite is greatly affected by the pH of oral fluids: In general, a more acidic environment causes hydroxyapatite to become more soluble, while a less acidic environment makes hydroxyapatite less soluble. The more undersaturated plaque fluid and saliva is, the greater the amount of dissolution. Integrates size effects and surface energy control into the overall reaction rate does matter a lot for comprehensive dissolution. Dissolution is induced by the formation of pits and continues with the spreading of their stepwaves. However, only the larger pits (of size greater than a critical value r*) are active, with stepwaves contributing to dissolution and the spreading velocities are also dependent on the pit sizes, decreasing with decreasing pit size. Size effects dominate the reaction when the crystallite sizes are of the same order as r*, resulting in self-inhibition of dissolution and even reaction suppression. Only when the pits are larger than a critical size, do they contribute to dissolution. Usually, biomaterials selection such as nano-sized mineral particles, their basic building blocks and synthetic sparingly soluble biominerals such as HAP behaves similarly.

Experimentally, the dissolution experiments can be initiated by the introduction of known amounts of crystal seeds, conducted using magnetically stirred (generally 450 rpm) double-walled Pyrex vessels thermostated at 37.0 ± 0.1 °C. Undersaturated solutions can be prepared by mixing calcium chloride and potassium dihydrogen phosphate with sodium chloride to maintain the ionic strength at 0.15 mol L−1. The pH can be adjusted to the desired value using diluted solutions of either potassium hydroxide or hydrochloric acid. Titrant addition can be triggered by a incorporating glass and reference Ag/AgCl electrodes. During dissolution, the electrode potential can be constantly compared with a preset value and the difference, or error signal, activated motor-driven titrant burets. And, hence a constant thermodynamic dissolution driving force can be maintained.

Ashish

Dear Gan,

Refer the site given below which illustrates the full seen of collagen processing.

Collagen-based medical products, which are offered on the market, are purified and prepared by routine technologies. They are applied successfully in reconstructive surgery, and the range of possible applications is further increasing.Major challenges for processing is mechanical stability and vascularization of the hybrid materials consisting of many structural elements.

Ashish

So specifically how is the antigenicity by EDC/NHS, Genipin and TG2

Dear Dr. Mohsin Abdullah Al-Shammari,

bioactive glass first synthesized by Hench and associates is the generic name of a class of amorphous material covering a wide range of bioactivity arising from variation of the chemical composition. The most common components of bioactive glass are SiO2, CaO, Na2O and P2O3.

The SiO2 content determines the chemical stability and the bioactivity of the Glass. Melt-derived glass which has SiO2 content larger than 60 wt% is chemically stable and hence is not bioactive. Bioactive glass with 45 wt% SiO2 is characterized by a high rate of bioactivity in that a high interfacial bond strength is established within 30 days.

Many additives including MgO, K2O, B2O3, Al2O3, Zr2O3, CaF2 and Ta2=5 can be added to bioactive glass in order to improve its mechanical and thermal properties or in order to enhance the workability range. However, a boundary conditions that limits themodification of the composition of bioactive glassi s the bioactivity property.

For more details, please see the source:

-COMPREHENSIVE BIOMATERIALS II Vol. 1 : Metallic Ceramic, and Polymeric Biomaterials

Editor Paul Ducheyne, Elsevier, ISBN: 978-0-08-100691-7 (2017)

Best regards, Pierluigi Traverso

Dear Karolina Nowak,

Synthetic cathinones are derivatives of cathinone, the principal psychoactive component of the khat plant. These designer drugs are potent psychostimulants that have grown in popularity among recreational drug users. From a forensic standpoint they are important because they have been widely associated with criminal and death intoxications.

Chemically, the synthetic cathinones are small amphetamine-like compounds bearing a betaketo functional group. Like their amphetamine counterparts, derivatization is commonly used to improve chromatographic and spectroscopic properties. These small polyfunctional compounds contain a ketone and an amine functional group. However, many of the forensically important cathinones contain a pyrrolidine moiety. These tertiary amines do not have the active hydrogen that is most often exploited with common derivatization approaches.

Over the past decade, synthetic cathinones have emerged as an important class of designer drugs within the United States. The proliferation of these new psychostimulants and their sought after effects among recreational drug users presents a formidable challenge for forensic toxicology laboratories. These drugs have been associated with impaired driving, intoxications and fatalities.

Nevertheless, not all laboratories are capable of testing for these drugs despite the fact that their use may have very serious public health and safety consequences. This is a significant concern in light of the fact that isotopically labeled internal standards are not yet available for all of the synthetic cathinones.

Cathinone decomposition products for all eighteen compounds can be characterized by this 2H loss. Synthetic cathinones are thermally labile and may undergo oxidative decomposition in-situ during GC/MS analysis. Although derivatization is a common approach to improve thermal stability and mass spectral properties, the chemistry of these polyfunctional drugs is inherently more complex than their non-ketone counterparts.Thermal decomposition products for synthetic cathinones included can be characterized chromatographically and spectroscopically. Factors influencing the thermal degradation of synthetic cathinones can be also investigated.

Ashish

Thank you for your prompt response Nicolas. I would like to be in touch with you for my other questions in chemistry. If you would like to help me, please send me an email to me. My email address is emailstoebi@gmail.com

Dear Tayfun Dikmen,

Generally, Gelation involves the formation of self-similar aggregates with a growth rate that increases exponentially. Apply initially couple of constraint conditions. Some of points are advised enlisted here.

(1)Freeze-drying- this will give gel a foam with a porosity of 80.90%, a water uptake capacity of 90% and a swelling index of 8.5-10. Gelation time and the properties of hydrogels and porous foams could be controlled by the ratios of RSF and non-solvent concentration as well as by the type of non-solvent and incubation temperature.

(2) PH must be between 2-4. If less than 2 it will defiantly form gelatin as pH is negative concentration of hydrogen algorithm. RSF (regenerated silk fibroin) hydrogels and porous foams can possibly be used for the encapsulation of cells and/or for the controlled release of both hydrophilic and hydrophobic drugs.

(3) Concentration must between ranges 0.5-10gL-1. Nonsolvent concentration can control the porous foam.

(4) Temperature between 5-70 0 C is advisable.

(5) Turbidity, rheology, light scattering and circular dichroism are other issues. Custody minimum turbidity will avoid early gelation.

Ashish

Dear Michał Wrzecionek, I attached interesting documents plus the following RG discussion on the same subject. What I want you to consider since you are using glycérol, you are dealing with a branches and not a liear polyester. Operating GPC is totaly different for both cases, so be carefull in selecting the operating parameters before running it. My Regards

Hi Imad,

We use a "homemade" buffer in our expeditions, where freezing at -80 is not an option. It is called NAP buffer and preserves well DNA and ARN. Here is a link to the article: https://onlinelibrary.wiley.com/doi/pdf/10.1111/1755-0998.12108?casa_token=qgIKvJ4dV1kAAAAA:sEJG807qo-hjPXIc9J54AKwwkxiiqsZSWmFdTd91VobTRfivCVxUYECwRzyUByrGGabSVsPZHrdl. We usually collect tissue samples of liver from carcasses, when it is not fresh, muscle/heart works better, given that liver degrades quick. For mammal specimens that we collect, we skin them in situ and fix the skin in formalin for a few hours and then store it in ethanol 70%, but the skinned body goes directly to ethanol 70% so that there is still a good stock of DNA. For feces Carlos Sarabia might know better.

Cheers,

Arlo

The list of additive manufacturing raw materials is immense and including them in keys words didn't make sense. Here are some common plastics in a list to contribute to discussion:

We have used CD68 as a pan-macrophage or M1 marker, whereas CD163 may be used as an M2 marker.

Abdelkader BOUAZIZ Ashang Luwang Laiva

Thank you very much to both of you for your help.

Changing the solvent is not an option, but I will try to wrap the drum with aluminium to see if it makes a difference.

Otherwise I've managed to get fibers at 2000 rpm using lower concentration, and playing around with voltage. They are not perfect yet but it's getting better. Thanks again!

Speaking from a chemistry point of view, amorphous materials are generally soluble in aqueous medium, so when deployed in-vitro, they are expected to be highly soluble and highly biodegradable, so they can produce desirable pharmacokinetics.

You are welcome. Best wishes for your future work

Thilini

Hi Justin,

A while ago I used glycerol as a plasticizer in a chitosan-based biomaterial at a concentration of 20% w/w compared to chitosan and did not see significant changes in cytocompatibility (using fibroblasts and osteoblasts) between the two materials. Unfortunately, I did not quantify the release of the glycerol in medium. Hope this can give you an indication for the development of your material.

When working on the project I gathered a few article on glycerol toxicity that might come in handy to you:

Also, although I did not experience cytotoxicity, I know of some colleagues working with poly(glycerol sebacate) (PGS) that did assess a reduction in cell viability due to the release of residual monomers from their material. Perhaps, in order to avoid cytotoxicity concerns, you could look at possible alternative to glycerol?

Hope this helps.

Lukas

The mechanic properties involve many aspects of materials so that it is hard to establish single modeling for comprehensive evaluation. It is better to specify which property is the object of your research. Concerning modeling efforts, stress and strain have been successfully assessed, but for the resultant mechanical properties, maybe we can not obtain a scale value without the discussion of microstructure. Thus, modeling the microstructure at first and then applying an analytical model that states the relationship between microstructure and property would be an indirect route affording your purpose. So phase-field or cellular automaton may be the core section in your modeling section. For connecting the AM parameters and formation conditions of microstructures, multi-physics modeling tool (e.g., COMSOL) would be applied at the first stage.

Thank you very much for your answer.

Hi,

Water for the contact angles is a convenient common standard, i.e. you state that material interacts that way with a water droplet. It can be opposite! E.g. I have observed the opposite effect with membranes from hydrophobic polymers, where the angle is equivalent to hydrophilic surface. So, I would recommend an experiment in your case.

As mentioned by Mr Damian, you must be sure that you can sterilise the sample without disrupting the plasma treatment. This is usually done through UV B exposure in a cell culture hood. You will need to find a lab which is capable of performing microbial culture. Some people use ISO 22196:2011 although this will only work on very smooth samples. Another option is to use a confocal microscope and either GFP tagged bacteria or a dye such as LIVE/DEAD to quantify bacterial attachment to the surface. We did some similar analysis here and I would recommend reading Andrew Hooks paper on '

Combinatorial discovery of polymers resistant to bacterial attachment. It is important to consider how you expect your polymer to kill bacteria, or just prevent the attachment.

Hi,

The grain size may influence the biocompatibility, so the alloys co-exist better with human tissue. Also, strength is always important for the implants. SPD may give rise to better properties on those aspects.

Lactoferrin coating maybe a prospect.

Generally specific surface area measurements give an indication of the available surface area which should correlate both with solubility and dissolution rate and therefore with bioavailability. It is necessary therefore to try to make poorly soluble active ingredients in nano form in order to enhance dissolution. Read the chapter: 'Characterization of Nanomaterials' In book: 'Metrology and Standardization of Nanotechnology' DOI: 10.1002/9783527800308.ch7

(January 2017)

Dear Zahid

You can use fish scales to extract collagen, since it is discarded as waste you will get large quantity of it.

Thanks Fauzi Mb and Andrei Rogoza

Why is it important to use calcium nitrate tetrahydrate instead of just calcium oxide when we want to load it on a catalyst support Hannah Read

Hello Alicja: We found during our shock heating experiments on blood:

Chemical and Structural Changes in Blood Undergoing Laser Photocoagulation¶

July 2004Photochemistry and Photobiology 80(1):89-97

DOI: 10.1562/2004-03-05-RA-102.1

Mechanistic comparison of blood undergoing laser photocoagulation at 532 and 1,064 nm

February 2005Lasers in Surgery and Medicine 36(2):155 - 165

DOI: 10.1002/lsm.20134

Using methemoglobin as a magnetic resonance imaging contrast agent

January 2007 Lasers in Surgery and Medicine

Thermal analysis of blood undergoing laser photocoagulation

December 2001IEEE Journal of Selected Topics in Quantum Electronics 7(6):936 - 943

DOI: 10.1109/2944.983297

SourceIEEE Xplore

Optical and magnetic resonance changes in photothermally coagulating blood

June 2002Proceedings of SPIE - The International Society for Optical Engineering 4609:10-19

DOI: 10.1117/12.430152

Conference: International Symposium on Biomedical Optics

that at some critical temperature (depending on the heating rate - an Arrhenius process) the fully oxygenated form of hemoglobin (which you have in blood exposed to air) converts over to met-hemoglobin with almost unit efficiency. We did not observe any liberation of free dioxygen from the sample despite the fact that the erythrocytes can complex a volume of oxygen 20x the physical volume of the cell and that Henry's law dictates that the solubility of gases in liquids decreases as a function of increasing temperature. We assumed, given this observation, that the oxygen became irreversibly chemically bound in the Fe(3+) met-Hb complex possibly as the superoxide ion O2(-). It's well known that met-Hb is not capable of exchanging oxygen in tissue - it a poison in this respect as a threshold concentration. So even though you have low laser power, you are focusing the beam and there is finite absorption of the probe beam, so you may have some local heating, so you may have some met-Hb conversion, which may account for your Raman observations? Hope this provides some clues! Best, John

It's already been used for 100s of years, so why not in the future too?

There are a variety of reasons that a given drug administration route is taken, among which are:

There are other factors too--often a drug can be given in multiple forms, and then it can come down to cost or patient comfort (for example, someone may prefer a daily pill to going in for an injection daily). The other factor in how a drug is commercialized is the form in which it was tested in animals. You will have a harder time getting a pill approved if all your in vivo tests are with tail vein injections, for example. But if your in vivo experiments involved an ingested oral dose, getting a pill approved is easier.

Dear Anish Hiresha Verma,

I recommend you to study below Articles:

1-

2-

Best Regards

Hi Anish,

In general, the excess of Ca2+ ions is toxic for cell and may cause death. In addition, the excess (or depletion) of Ca2+ can cause biochemical imbalance in the cell. You could check if this cell has any type of Ca2+ transporter as a way to avoid this intracellular accumulation.

Best regards.

Glut does not provide "immediate penetration", but for single layer cell culture it works pretty fast, but still I would not recommend to have fixation time shorter than 0.5 hrs. Generally speaking, with some exceptions, specimens can be stored in glut fixative for as long as at least one month in refrigerator. But why would you want to do it? Dehydrate, mount and coat you specimens and you can store them for years (preferably in desiccator).

Dear Anish,

Most important thing to keep in mind is mode of action of your drug, through which you can determine the downstream assays. If you don’t know the exact mechanism then you can use general assays. As regard to anticancer activity, you can use:

7-AAD or the cheaper MTT assay detect apoptosis and determine how potent your drug is.

You can also use Propidium Iodide (PI) to determine if it can induce cell cycle arrest.

I would say even distribution of cells within the gel. Uniform distribution is the key and spacial dispersion dependant upon target tissue would also be important for cell-cell interactions. But also we are in the infancsy stage of bioprinting so we are still learning, furthermore we are still learning more about stem/progenitor cells.

Zeolite A will gradually degrade in a water flow. This is why attempts to use it's cation exchange properties on a large scale are not successful.

This also applies to A bound into pellets etc.

As a matter of fact there are many applications in biomechanics and biomedical engineering involving SMA. In addition to previously-cited ones, it is possible to consider the large use of shape memory alloys in clinics related to cardiovascular systems, and specifically associated to stents, grafts or similar devices, also coupled with different physics, for instance associated to local drug eluting processes.

Moreover, SMA are widely employed for conceiving smart devices and prosthesis tools (for instance, artificial sphincters -https://www.google.ch/patents/EP2409668A1?cl=en -).

I agree with Professor Gettleman. PMMA is widely used for removable partial and complete dentures fabrication. Fungus infections are usual in patients who use the denture for long periods, however, antifungal medications can reverse this situation. On the other hand, alergenic reactions to PMMA are not usual.