ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

Browse by research topic to find out what others in your field are discussing.

Browse Topics

  • Wu Yongyan added an answer in FLUENT:
    How to use UDF under symmetry boundary condition in Ansys FLUENT?

    I'm modelling open channel flows by commercial software Fluent. I've set the surface as symmetry boundary condition, now I want to change the dissipation rate at this boundary,but UDF seems to be unactivated under symmetry boundary condition. How can I realize this idea in Fluent?

    By the way, I also tried to use DEFINE_SOURCE to change the value of dissipation rate near the boundary region, but in Ansys Help Guide, it is said that you can use DEFINE_SOURCE to specify custom source terms for the different types of solved transport equations in FLUENT. I guess the source term is added to the dissipation rate transport equation, rather than the dissipation rate value in certain region. So I think this idea is unfeasible.

    Thank you very much for discussing with me and providing suggestions!

    Wu Yongyan

    Dear Jaafar,

    Yes, you got it. I want to simulate the damping effect of water surface on turbulence. Can I realize it by commercial software?

  • Nazanin Hamnabard asked a question in Capacitance:
    Impedance, CV , capacitance, Conductivity.?

    I did electro chemical experimental based on Impedance and CV, I found the conductivity my sample is low (low ESR in high frequency) and capacitance from CV of the same sample is high in compering other samples. Please let me to know how it is possible...

  • Madhuri Kanala added an answer in Yogurt:
    How to increase the shelf-life of curd/Yogurt? What packaging materials should be used to do so?

    Working on increasing the shelf-life of curd and curd based preparations.

    Madhuri Kanala

    This might help.

  • Stanton de Riel added an answer in Simvastatin:
    Is Simvastatin the best Statin to be combined with Colchicine?

    According to one of Garin Sahip's studies, Rheumatology International 28(3):289-91 · January 2008, the safest combination of Colchicine is with Simvastatin.

    My question is: does anybody have any life-experience to confirm this?

    Stanton de Riel

    Though the statins are quite effective (I don't know the data on comparative interaction), stanol esters and soluble fiber are also shown to moderately reduce cholesterol absorption, with low incidence of side effects. (General food intake moderation has also been noted with certain pine nut species, which alter bile secretion and induce dysgeusia. Not recommended, though!) reference: http://www.foodauthority.nsw.gov.au/_Documents/science/pine_nuts_pine_mouth_


  • Lucio Munoz added an answer in Rationality:
    How do the economists define self-interest and rationality?

    How do the economists define self-interest and rationality so as to make these concepts different from the animal instincts, beast behaviour, and barbarism? What is that which forms and what is that which does not form the self-interest? Moreover, are these the behavioural guides for all individuals? Are these the collective guides for policy making? 

    Given the propensity for free riding in each economic-beast, does not the collective policy results into a collective free riding of those who make policies over those who do not?

    Lucio Munoz

    Dear friends as food for thoughts, has anybody look at different aspects of economics, from Adam Smith......to arrows imposibility theorem from a conjunctural preference/options/decisions point of view?....If you do, you may see a different world and consequences....Remember conjunctural thinking is at the heart of sustainability thinking...

    In the future I will bring some ideas about this... for the moment...

    Wish you all a wonderful day...

  • Adewole K. S. added an answer in Clustering Algorithms:
    Can anyone give me more details on the Markov clustering algorithm and a tool that implements it?

    From my understanding Markov clustering (MCL) algorithm is a graph clustering algorithm that takes weighted graph as input and uses Random walk approach for probability assignment of each node on the graph. What is not clear to me is how MCL uses Frobenius norm to perform the final clustering. Also, is there a tool or java codes that I can easily simulate with or adapt? Thanks.

    Adewole K. S.

    @Fabrice, thank you so much for this information.

  • Edward Moh added an answer in Cysteine:
    Are there other residues subjected to carbamidomethylation in addition to cysteines?

    hi to all,

    I'm studying a protein having 3 cysteines. When I perform the reaction with IAM, I notice that the protein is being Carbamidomethylated on four residues. are there other residues in addition to cysteines subjected to carbamidomethylation?

    Edward Moh

    That is a definite yes. This is actually very common in methionine, and we observe that quite routinely when we are manually looking through glycopeptide MS/MS data. There are diagnostic patterns in the tandem MS, and you can observe them at a different elution time on a reversed phase column.

  • Jose Victor Nunez Nalda added an answer in Kinematics:
    Can someone help me with a good reference to study about "Kinematic and Inverse Kinematic and Dynamic of Humanoid Robots"?


    My humanoid robot have 14 degrees of freedom in total. each leg have 6 DoF and waist have 2 DoF.

    I want to study about control of it and I need the method for generate a model for Dynamic of it Using Denavit-Hartenberg method.

    Can someone Help me what reference I should study.

    Thanks a lot

    Jose Victor Nunez Nalda

    you can take a look at prof kajita text book on humanoids

  • David John Collins added an answer in Droplet Microfluidics:
    What is the minimum size of droplets droplet microfluidic can achieve?

    It is well known that size of the channel geometry, surfactants, fluid viscosity, surface wetting can be used to tune the range of the droplet size. Is there any systematic guide on the effects of these parameters? Moreover, what is the minimum size of droplets can literature design achieve? I saw most of literature papers make droplets of 5-120 microns in diameter.

    Is there any scientific paper discussing about this? Any input will be appreciated. Thanks.

    David John Collins

    According to this paper the droplet size should scale simply with the ratio of the two focussed flow rates, though only down to ~220nm are predicted and verified: 


    As others have said, sub-micron diameters are absolutely possible.

  • Hayk L. Khachatryan added an answer in Indium Tin Oxide (ITO):
    Can ITO be deposited using vacuum E-beam evaporation?

    I am trying to deposit ITO on glass using E-Beam evaporator and anneal it in Nitrogen using RTA. The E-beam evaporator works on a vacuum of 1e-7 Torr. After deposition, the colour of the film was dark brown. After annealing the sample, it went transparent. also the resistivity was reduced, but still relatively high (1000 ohm/sqr) for a transparent electrode.

    I have gone through the literature, and most of the recipes use some partial oxygen pressure in deposition. I can't do that in vacuum E-Beam, so I tried to anneal it in dry air, and resistivity have actually been reduced to (500ohm/sqr). 

    Can any one help me explaining this in a physical way? Oxygen deficiency (deviation from stoichiometry) is needed for conductive ITO. Why do we use partial oxygen pressure in deposition?

    is there a working recipe for depositing ITO using vacuum E-Beam evaporation? 

    Hayk L. Khachatryan

    Hi  Mutasem 

    Usually, concentration of oxygen in the ITO lattice has key influence on its properties (e.g. conductivity). Highly possible that during EB deposition significant amount of oxygen is lost due to very high vacuum. Formed oxygen vacancies may strongly change conductivity, and may be reason for darkening as well. It is suggested to add oxygen radicals to the e-Beam deposition process to control its concentration.

    Please refer to J.S. Kim, et al. “Effects of oxygen radical on the properties of indium tin oxide thin films deposited at room temperature by oxygen ion beam assisted evaporation” Thin Solid Films 377-378 (2000) 103-108.

  • John Sosa added an answer in Focused Ion Beam:
    What is the best (fee) software for image segmentation?
    I made FIB-SEM measurements on three fuel cell electrodes. Unfortunately the contrast in pictures is not that good, so I have to do image segmentation by hand. (Maybe anybody can give me some better suggestions, but I already tried a lot) The group I work in cooperation uses Amira 4.3 for image analysis. I would prefer to do the segmentation on my own, so I needn’t travel that much. So I am looking for software which is compatible to Amira and I can run at home to do the segmentation. Up to now I already spent 300 hours of work on one of the samples an it´s done half. Maybe any one has a suggestion how to become faster using automated segmentations which are made for bad contrast.
    John Sosa

    I know this is a very old post, but if you are still in need I would defintely recommend you visit www.MIPAR.us.

    It is very powerful and intuitive 2D/3D image analysis software, focussed on segmentation, written by scientists/end-users, and is about to be released as a free trial on December 14th. You can sign up on the site as well as submit images/datasets to test.

    There are many image analysis options available, but I think you may just find MIPAR to be something special if you give it a try!

  • Colin Cheng added an answer in 3T3 Cells:
    Why do my 3T3 cells "atropy" & die almost instantly on changing from abx to abx-free MDEM?

    I have 3T3 cells seeded onto 24-well plates with a density of 6000 cells/well in MDEM containing 10% BCS and 1/200 streptomycin-pencillin. The cells were incubated for 72 hours at 37 degrees in 5% CO2 until confluence reached about 60%. 

    I was about to perform an assay that required the addition of bacteria to the wells, so I changed the media to an abx-free MDEM, containing the same 10% BCS but no antibiotics. I noticed that almost instantly, many cells started to shrink and atrophy ("look unhealthy"), and the cytoplasm appears to become dotty and full of tiny granules. Interestingly, this atropy was mainly limited to cells on the right side of the 24-well plate. The cells do not stain well with Giemsa stain, compared to healthy 3T3 cells. Any suggestions as to what might be the issue? I've attached two images highlighting the differences. 

    My supervisor did the same experiment using the cells I prepared, and did not experience any issues using the same abx-free MDEM. 

    + 1 more attachment

    Colin Cheng

    I've been troubleshooting for a while to no avail. The problem is not with the media, and in fact, I can change the media reliably without damaging the cells. However, when I try to wash the cells with PBS and then fix them with 10% formalin in PBS, I get the same shrinkage of cells.

    Drying is not likely to be problem as the liquid in the wells was replaced within the span of 2-3 minutes. The reagents are not contaminated as my supervisor used them without issues. I have tried to be gentle by adding the PBS by dripping it down the side of the well instead of dropping them directly on top of the cells. Any ideas? I'm suspecting it's something very minor that I overlooked completely. 

    I've attached an image that better illustrates how my cells look like. 

  • Mohd Khalid Khalil added an answer in Tilapia:
    How can I determine the digestibility of feed on fish without using chromic oxide as indicator?

    Is there any method to determine the digestibility of feed on fish without using chromic oxide? Most literature I've found used chromic oxide as an indicator. However, I didn't incorporated the chromic oxide in the feed that I tested on the fish. The fish I'm using is red hybrid tilapia.

    Mohd Khalid Khalil

    Thank you Hoseini and Mansour. Really appreciate the idea.

  • Juan Weisz added an answer in Invariant Theory:
    Did Einstein obtain field equations directly from the principle of equivalence?

    "THE MEANING OF RELATIVITY” is a description of General Relativity by Einstein.


    Einstein wrote: "It is evident that the formulation of the general theory of relativity assumes a generalization of the theory of invariants and the theory of tensors; the question is raised as to the form of the equations which are co-variant with respect to arbitrary point transformations. The generalized calculus of tensors was developed by mathematicians long before the theory of relativity. Riemann rst extended Gauss's train of thought to continua of any number of dimensions; with prophetic vision he saw the physical meaning of this generalization of Euclid's geometry. Then followed the development of the theory in the form of the calculus of tensors, particularly by Ricci and Levi-Civita. This is the place for a brief presentation of the most important mathematical concepts and operations of this calculus of tensors". Page 68.

    Many have claimed that in 1915 Hilbert discovered the correct field equations for general relativity before Einstein but never claimed priority. Following article shows that this view is in error.

    Belated Decision in the Hilbert-Einstein Priority Dispute

    According to the commonly accepted view, David Hilbert completed the general theory of relativity at least 5 days before Albert Einstein submitted his conclusive paper on this theory on 25 November 1915. Hilbert's article, bearing the date of submission 20 November 1915 but published only on 31 March 1916, presents a generally covariant theory of gravitation, including field equations essentially equivalent to those in Einstein's paper. A close analysis of archival material reveals that Hilbert did not anticipate Einstein. The first set of proofs of Hilbert's paper shows that the theory he originally submitted is not generally covariant and does not include the explicit form of the field equations of general relativity.


    If equivalence principle was origin of general relativity, how Einstein have obtained Field equations?

    Juan Weisz

    I think I see many ideas in GR which have nothing to do with the equivalence


  • Frederik Wendelboe Lund added an answer in Confocal Microscopy:
    Can you store NBD-cholesterol samples overnight in PBS or glycerol?

    Hi there!

    I am currently doing my master thesis and are working in cholesterol trafficking in drosophila. Have any of you have experience with storing you samples after tagging them with NBD-cholesterol in e.g. PBS or mouting them in glycerol and waited until the next day to do confocal microscopy? I am worried to try it because it might influence the cholesterol and I because confocal is usually done directly after fixation.

    I am looking forward to hearing your experiences.

    Kind regards Cæcilie Sønderholm

    Frederik Wendelboe Lund

    Hi Cæcilie

    It is not clear to me if you are planning to fix the cells before overnight storage. However, if you are planning to fix them you should be aware that lipids can still move by diffusion in the membrane of cells fixed with 3% PFA. For a stronger fixation you can use 3% PFA and 0.5% glutaraldehyde.

    Additionally, I would advice you not to use NBD-cholesterol. Several studies have shown that the biophysical properties of NBD-cholesterol are very different from the properties of cholesterol. For a review you can see: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3626500/ and links therein.

    Rather than NBD-cholesterol I would recommend TopFluor cholesterol (also known as BODIPY-cholesterol) which is available at: https://www.avantilipids.com/index.php?option=com_content&view=article&id=1905&Itemid=306&catnumber=810255

    TopFluor cholesterol is a lot better than NBD-cholesterol but not quite as good as dehydroergosterol (DHE). On the other hand, DHE is very difficult to image and requires a specialized UV-sensitive microscope while TopFluor cholesterol has approximately the same fluorescence properties as GFP.

    Best of luck with your project

  • Sarath Rathnayake added an answer in Occupational Therapy:
    Are physical or mental activities more effective in improving ADLs in patients with Alzheimer's Disease?

    a question in the field of Occupational Therapy

    Are physical or mental activities more effective in improving ADLs in patients with Alzheimer's Disease?

    Sarath Rathnayake

    Improving ADLs in patients with Alzheimer's Disease is a one the major goals in rehabilitation process.  Holistic approach is the best way and improving ADLs helps to maintain independence. In this way, providing safe environment, helping daily routine, helping to be a productive member with in the family system are essential strategies. Hence, both physical and mental activities  help to gain independent  and improve the quality of life in patients with AD. Family is the best place for the patients with AD and their role is significant. 

  • Mohd Badrul asked a question in Hemocytes:
    How to make withdrawn hemolymph efficiently?

    Sometimes when i have done total hemocyte count on Neubeur counting chamber, the hemocyte come in very little amount.

  • Lynn A Slepski added an answer in Blast Injuries:
    Are there any mobile apps for mass casualty blast injury ED documentation?

    Are there any mobile apps for mass casualty blast injury documentation in the emergency room, especially for war crimes, crimes against humanity purposes? Because the ED is usually frantically trying to triage and save lives, this sort of documentation is very difficult, but I read somewhere about a competition in the Hague that someone developed an app to be used in this situation - it didn't win the comp, but it would win my vote if I could find it! Please help...!

    Lynn A Slepski

    So here is the CDC mobile app at https://emergency.cdc.gov/masscasualties/blastinjury-mobile-app.asp. This iPhone and iPad application supports pre-hospital and hospital healthcare professionals in preparing for and responding to terrorist bombings and other mass casualty explosive events. In addition, it includes a link to CDC's extensive "blast and bombings" website.

    Alternately, Hopkins was designated as a Center of Excellence by the Department of Homeland Security. They developed EMCAPS 2.0 which is supposed to help estimate and categorize victims from a variety of scenarios, including IEDs. I've not worked with the app....but they got a lot of money to develop it. Here's a media announcement that includes a link.   http://www.hopkinsmedicine.org/news/media/releases/johns_hopkins_scientists_launch_advanced_disaster_planning_and_flu_forecasting_apps.

    Good luck and I'll keep hunting.


  • Nguyen Truong added an answer in Real-Time PCR:
    How do I publish qPCR data in a bar graph?
    I have my raw data according to two groups of different types of animals that are being tested with pharmacological compounds or PBS. I am using the 2deltaCT method. I've seen different papers with many ways of graphing results, lets say for instance: relative expression vs gene of interest, fold change vs gene of interest, RQ vs Gene. Does anyone have an opinion on the best way to depict your relative quantification data?
    Nguyen Truong

    Please check the example below. I have asked many of my colleagues and all of them calculated the SE of the fold changes, not the propagated SE calculated as in the formula of Applied Biosystems guide: s^2=s1^2 + s2^2. I'm confused now. Which one is the correct way? 
    By the way, do you average the ddCt and get the power of that mean or do the power first and get the mean of the fold changes? I did the latter one but it gave me the fold change of control group not exactly equal to 1.00 and my boss doesn't like it. 

  • Rafik Karaman added an answer in Cancer Cell Line:
    Do we have "mesenchymal" breast cancer cell lines?

    Breast cells are epithelial in origin, however during EMT, the epithelial phenotype (and maybe genotype) is replaced by by the mesenchymal phenotype. 

    This makes me wonder if we have a mesenchymal breast cancer cell lines as well.

    Rafik Karaman

    Dear Hanie,

    Attached please find a paper that covers the answer to your question. I have copied some of the methods for quick view.

    Research articleMesenchymal stem cells mediate the clinical phenotype of inflammatory breast cancer in a preclinical model
    Lara Lacerda12, Bisrat G Debeb12, Daniel Smith12, Richard Larson12, Travis Solley1, Wei Xu12, Savitri Krishnamurthy23,Yun Gong23, Lawrence B Levy1, Thomas Buchholz12, Naoto T Ueno24, Ann Klopp1† and Wendy A Woodward12*†

    Breast Cancer Research 2015, 17:42 doi:10.1186/s13058-015-0549-4

    Inflammatory breast cancer (IBC) is an aggressive type of breast cancer, characterized by very rapid progression, enlargement of the breast, skin edema causing an orange peel appearance (peau d’orange), erythema, thickening, and dermal lymphatic invasion. It is characterized by E-cadherin overexpression in the primary and metastatic disease, but to date no robust molecular features that specifically identify IBC have been reported. Further, models that recapitulate all of these clinical findings are limited and as a result no studies have demonstrated modulation of these clinical features as opposed to simply tumor cell growth.

    Hypothesizing the clinical presentation of IBC may be mediated in part by the microenvironment, we examined the effect of co-injection of IBC xenografts with mesenchymal stem/stromal cells (MSCs).

    MSCs co-injection significantly increased the clinical features of skin invasion and metastasis in the SUM149 xenograft model. Primary tumors co-injected with MSCs expressed higher phospho-epidermal growth factor receptor (p-EGFR) and promoted metastasis development after tumor resection, effects that were abrogated by treatment with the epidermal growth factor receptor (EGFR) inhibitor, erlotinib. E-cadherin expression was maintained in primary tumor xenografts with MSCs co-injection compared to control and erlotinib treatment dramatically decreased this expression in control and MSCs co-injected tumors. Tumor samples from patients demonstrate correlation between stromal and tumor p-EGFR staining only in IBC tumors.

    Our findings demonstrate that the IBC clinical phenotype is promoted by signaling from the microenvironment perhaps in addition to tumor cell drivers.

    Materials and methods
    Cell culture
    The IBC cell line SUM149 was obtained from Asterand (Detroit, MI, USA) and cultured in Ham’s F-12 media supplemented with 10% fetal bovine serum (FBS), 1 mg/mL hydrocortisone, 5 mg/mL insulin, and 1% antibiotic-antimycotic. Human-derived bone marrow MSCs were obtained from EMD Millipore (Billerica, MA, USA) (Part #SCC034, Lot N61710996) and cultured in alpha minimum essential medium (MEM) supplemented with 20% FBS and 1% penicillin/streptomycin/glutamine.

    Hoping this will be helpful,


  • Raveendra Nath Yasarapu added an answer in Climate Change:
    Is it time we shift emphasis from technological solutions to climate change & focus on the 'Human Dimension'?

    Isn't the obvious solution and the elephant-in-the-room 'BETTER HUMAN BEINGS'? Shouldn't the focus be on better human beings rather than better technology? Why is it that everyone wants to develop better technology rather than focus on better humanity? Because no one has the answers and no one wants to change themselves? In environmental degradation, is it not obvious that nature can heal itself, if only left alone, and it is we humans who need regulation? Many natural parks managers do just that; seal off the area from human interference to let nature heal and recover. It is classified as 'Strict Nature Reserve"by IUCN. Complacency and inaction are not advocated here, as many have misunderstood, but the shifting of focus from technology to the human being. As technology is no match for human greed, isn't introspection & restraining ourselves more relevant than developing more technology, which caused the mess in the first place, by making it easy for a few to consume more? Since technology is only a short term quick fix which fails after a short time, isn't the real problem our addiction to material consumption & our lack of understanding about human nature? Isn't developing more technology sustaining the addiction instead of correcting it, leading to more complex problems later on, needing more complex technological quick fixes like higher drug dosages, more ground troops & equipment, (along with their debilitating side effects) in the future? Isn't this the vicious addiction circle we are trapped in? As researchers, do we merely buy more time with technology OR go to the very root of the problem, the human being?

    A lot of hue and cry is made about climate change and the environment in general. Public and private money is poured into research to study its effects on the environment, sustainability etc. Should we study nature or ourselves?

    " Our studies must begin with our selves and not with the heavens. "-Ouspensky

    Human activities have been found to have a direct correlation to climate change and its impact on the environment(I=P x A x T, the Ehrlich and Holdren equation), in spite of what some complacent sections say to protect their own self interests.

    We hardly know about Human nature. We can scarcely predict human behavior. We need to find out why we think like we do and why we do what we do and why, in spite of all knowledge and wisdom, consume more than what we need, in the form of addictions to consumption and imbalance not only ourselves but also the family, society and environment around us..
    Humanity is directly responsible for all the unnatural imbalances occurring on the planet. Yet we refuse to take responsibility and instead focus on climate change, or fool the public exchequer with a 'breakthrough in renewable energy just around the corner'. We scarcely know what drives human beings. If we had known, all the imbalances around us would have had solutions by now, given the amount of money plowed into finding such solutions. Are we blindly groping in the dark of climate change because we don't know the answers to our own nature?
    Is it not high time we focus on what makes us human, correct our consumptive behavior and leave nature to take care of climate change? Why focus effort on 'externals' when the problem is 'internal'- 'me'?
    Aren't we addicts denying our addiction and blaming everything else but ourselves?

    " We are what we Think.

    All that we are arises with our thoughts.

    With our thoughts, we make the world." - Buddha 

    IMHO, We don't need to save the World. It is enough if we save ourselves from ourselves. The need of the hour is not vain glorious interventions, but self-restraint and self-correction!

    The Mind is the Final frontier.

    + 2 more attachments

    Raveendra Nath Yasarapu

    Dear Roberto,

    Thank you for your wonderful post and welcome to the discussion.

    The points that are being put forth here are roughly:

    1. That human actions are the main reason for the imbalances we face currently as humanity. Attributing these to climate change and trying to combat climate change is IMHO, futile and will take us only half-way. The correlation between 'causes' and 'effects' in this particular problem will always be unknown because while the 'effects' are physical and tangible and can be seen in the grosser material plane of everyday existence, the 'causes' are non-physical, intangible and exist in subtler planes. In any case, as children and teenagers, we may have passed on the blame to factors unseen, but it is high time now that humanity grows up and showing maturity as men, takes responsibility for the mess we ourselves have made. Anyone denying that humans(anthropocentric) did not cause it and can go on having a good time at the cost of the environment can be IMHO,  disregarded as teenagers, immature.

    2. This problem(the definition and causes for this are itself unknown and debatable, as has been explained above) has two facets of approach . Firstly, it has been attempted to be solved by western science experts with technology. Technology is a wonderful creation of humanity, but is in no way a replacement or substitute for the original. A doctor can give a gastric bypass or a bionic limb to a patient, but these can never be a real and satisfying substitute for the original which is only nature's. So is colonizing Mars. The meaning of nature itself is 'the original, the very essence'. Also technology has a property of being subservient to human nature. In the hands of the good and well-meaning, it is a great positive force, but in the hands of the misguided(for ex; ISIS), it can be an instrument of great destruction. In any case, the roots lie with us humans and developing more technology without understanding human nature would be placing the horse before the cart. The objective should be to develop technology that is used for the welfare of mankind, and not against. And when that happens, we are clearly missing something and need to introspect and retrace our steps as to where the fault lies.

    3. On the whole, in the name of making life easier, technology has compounded human existence. It has created more problems in the name of solving them. The reasons again are simplistic. Technology is neutral. Humanity on the other hand, has roughly two facets-The Lower Negative (selfish) and the Higher Positive (altruistic) motives. It all depends to which facet of human nature technology is yoked to-The negative lower or the positive higher. The original inventors and discoverers of technology mostly had altruistic motives in mind and were exceptional people who received the gifts from nature. But the gifts of technology are misused by the selfish few to mass produce technology on a industrial scale(using up the Earth's resources and calling it 'development', while profiting themselves) and selling it to unsuspecting consumers as the 'panacea' to all their ills with clever psychological advertising of a 'lifestyle', thus setting of a vicious cycle of addiction and craving for material consumption, in the hope of finding happiness in matter and its consumption.

    To put it succinctly, the present imbalance can be ascribed to, overconsumption by a few with the aid of technology. Technology which could/should be used altruistically, is used for selfish ends. A problem created by technology abuse cannot be treated with the application of more technology. We need to come out of the box(of material addiction). Ehrlich and Holdren have clearly shown the direct effect technology has on consumption and degradation of the environment(I=PxAXT). In spite of knowing the prime causes, why do we still want to apply technology to problems created by technology abuse?

    The answers lie in human nature, and not in technology. A short description is given in the next post.

  • Caitlin Regalia asked a question in Publications:
    Recommendations for publications on the topic of why we study failed scientist?

    Recommendations for publications on the topic of why we study failed scientist? 

  • Negin Minaei added an answer in Settlements:
    Is there any recent development on rank-size model for rural settlements?

    Sonis and Grossman (1984) introduced a semilogarithmic model for rank-size rule for explaining rural settlements. Does any one know are there any other models? 

    Negin Minaei

    Dear Xuefeng, I know that aside from the rank-size model ,there was a rule of thumb applied in many countries which was 5000people, less than that rural, more urban. This number varies in different countries, those with more population increased the number and less populated countries have smaller numbers. In some countries though the criteria to distinguish a settlement as urban or rural has changed and it is not based just on the population any more but in other factors including having or not having a municipality, the national/regional roles and responsibilities and the level of governmental support. For example a settlement may have less population comparing to other urban areas but as it is a tourist hub(has the national role of tourist attraction) and has a municipality it is considered an urban settlement therefore it gets governmental budget ;some settlements may have merely one of these roles as political or religious or educational or entertainment roles and they are considered urban too. So it depends on the strategic national plannig of that country. Sorry that I cannot recall what it was called if it was a model.

  • Zairil Hafizi asked a question in Pitting Corrosion:
    What is the mechanism of corrosion of stainless steel (304 and 316) in condensate water? If pitting corrosion or erosion occur, what are the causes?

    Seek your expertise.

  • Rafik Karaman added an answer in Microalgae:
    What is the best method for harvesting microalgae?

    I use strain Naviculla sp., Melosira sp., and Skeletonema sp.

    First two is benthic microalgae

    It was cultivated in open pond system.

    I did the harvesting by manual filtration, but I found it very time consuming and labour consuming for harvesting the cell.

    Rafik Karaman

    Dear Abinubli,

    Attached please find some publications that cover the answer to your question. I have copied titles and abstracts for some of these publications for quick view:

    1-Flocculation as a low-cost method for harvesting microalgae for bulk biomass production
    Dries Vandamme, Imogen Foubert, Koenraad Muylaertemail
    KU Leuven Kulak, Laboratory Aquatic Biology, E. Sabbelaan 53, 8500 Kortrijk, Belgium
    DOI: http://dx.doi.org/10.1016/j.tibtech.2012.12.005
    showArticle Info


    The global demand for biomass for food, feed, biofuels, and chemical production is expected to increase in the coming decades. Microalgae are a promising new source of biomass that may complement agricultural crops. Production of microalgae has so far been limited to high-value applications. In order to realize large-scale production of microalgae biomass for low-value applications, new low-cost technologies are needed to produce and process microalgae. A major challenge lies in the harvesting of the microalgae, which requires the separation of a low amount of biomass consisting of small individual cells from a large volume of culture medium. Flocculation is seen as a promising low-cost harvesting method. Here, we overview the challenges and possible solutions for flocculating microalgae.

    Microalgae are a promising new source of biomass for production of food, feed, fuel, or chemicals, but the cost and energy demand of large-scale production is still too high.
    An efficient low-cost method for harvesting microalgae is essential for large-scale and low-cost production of microalgal biomass.
    In this paper, we give an overview of different approaches for achieving flocculation of microalgae, each with their advantages and disadvantages.
    Flocculation of microalgae can be achieved through chemical, biological, and physical methods and by genetic modification.
    The global demand for biomass for food, feed, biofuels, and chemical production is expected to increase in the coming decades. Microalgae are a promising new source of biomass that may complement agricultural crops. Production of microalgae has so far been limited to high-value applications. In order to realize large-scale production of microalgae biomass for low-value applications, new low-cost technologies are needed to produce and process microalgae. A major challenge lies in the harvesting of the microalgae, which requires the separation of a low amount of biomass consisting of small individual cells from a large volume of culture medium. Flocculation is seen as a promising low-cost harvesting method. Here, we overview the challenges and possible solutions for flocculating microalgae.
    microalgae, biomass, biofuels, flocculation, coagulation, separation, harvesting

    2-A Comprehensive Overview on Various Method of Harvesting Microalgae According to Indian Perspective
    Jigar H Shah*, Abhijeet Deokar*, Kushal Patel*, Keyur Panchal*, Alpesh V. Mehta
    The global demand of fossil fuel is increasing day by day due to urbanization, industrialization and increasing global population. Moreover, worldwide reserve of fossil fuel is vanishing at an alarming rate. Concentrating on the limited stock of fossil fuel, several effort have been started to search for sustainable renewable bio fuels like bio ethanol and biodiesel. Biodiesel extracted from the microalgae is an most promising source to cope up the global demand of fossil fuels. One of the major problems associated with the conversion of algae into biodiesel is the harvesting of algae. Harvesting of algae can be carried out by number of methods such as; sedimentation, flocculation, flotation, centrifugation and filtration or a combination of any of these. This paper discloses various method of harvesting microalgae from a aqueous solution for the production of biodiesel. Among the various method of harvesting, floatation is the most promising method for harvesting microalgae.
    Keyword- Microalgae, Biodiesel, Harvesting, Flocculation, Centrifugation, Flotation, Filtration
    Hoping this will be helpful,

    + 1 more attachment

  • Fahad Abdullah asked a question in Film Analysis:
    Can anyone tell me the steps of Le-Bail refinement for thin film analysis. I want to find the lattice parameters of the thin film?

    Le Bail Refinement

  • Qinghao Zhang added an answer in Transcriptome Sequencing:
    Can a partial cDNA sequence be submitted to Genbank and get an accession number?

    There is no public database for the species I used in my study and recently we made a transcriptomic sequencing. Now I want to conduct qPCR to determine the expression level of genes I am interested in. However,just partial cDNA sequence of these genes could be acquired from the finished transcriptomic sequencing database (sequence blast has been done). It is available for me to design qPCR primers, but is it OK to submit the partial gene sequence onto Genbank and get an accession number?

    Qinghao Zhang

    Hi guys! Thank you for your answers. They are very helpful.

  • Chandravadan Trivedi added an answer in Empathy:
    Empathy with Higher Education students: essential feature in the teacher or waste of time?

    Lately, I hear that empathy in a Higher Education teacher is a waste of time because the most important feature in that level is the knowledge. What is your opinion?

    Chandravadan Trivedi

    The first teacher of a growing child are the parents & the next in line are the teachers right from montessary to higher levels. In most of the developing countries, parents may not be in a position to exactly guide their kids & it is here that the teacher has to step in. Modern world is changing too fast & the teachers are one of the best guides to the one going for higher education.

    Higher education is knowledge and experience, whether in labs.fields,practical assignments,internships, where a student has to learn & climb through the grape wine of future success.Students always falter & it's here that the teachers has to chip in. Without empathy, they could be confused, forlorn, and could fall prey to misinformations.

    As Gerard C Mass has rightly said, they are the leaders of tomorrow & with out empathy & proper guidance how would the scenario look if these confused Generation Next will be saddled with the responsibility of teaching/guiding/administrating our children and their children, in turn?

    Empathy does play an important role in shaping their future careers, & is very much an essential part of higher education.  

  • Madhuri Kanala asked a question in Carrageenan:
    At what temperature and pH does konjac have the greatest synergistic effect when combined with either xanthan or carrageenan?

    At what temperature and pH does konjac have the greatest synergistic effect when combined with either xanthan or carrageenan?