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  • Laura Stancampiano added an answer in Parasites:
    If you have two parasites in the one host, is there a model or equation that would help work out if they are interdependent vs. the age of host?

    I have some intermittent data on age of host (Perca fluviatilis) against occurrences of Diplostomum and Tylodelphis.  The occurrences appear to 'oppose' each other but I need something to say if this is merely an 'artefact' of the data or not.

    Laura Stancampiano · University of Bologna

    look also here:

    https://www.researchgate.net/post/STATA_GLM_and_negative_binomial_regression1

  • Which stain is best recommended in micronucleus test assay for human blood smear?

    I have to do the micronucleus test assay, from the human peripheral blood smear in workers exposed to some heavy metals, in order to quantify the possible DNA damage. Please suggest me which stain is best recommended and in which proportion.


    Uppalapati Lakshmi Narasaiah · Ben-Gurion University of the Negev

    May-Grunwald stain

  • How does ethnic/migrant entrepreneurship contribute to the transformation of cities?

    I am currently working on 'ethnic/migrant entrepreneurship, ethnocultural diversity and innovation in cities'.

    Within the process of the transformation of ethnic neighbourhoods into places of leisure, tourism and consumption (for example, Aytar and Rath, 2012; Hiebert, Rath and Vertovec, 2015; Rath, 2007), the commodification of ethnocultural diversity by ethnic/migrant entrepreneurs, amongst others, is crucial. However, I found no references on how such a diversity commodification takes part in the transformation of the - whole - city.

    Thus, I would infer that the transformation of ethnic neighbourhoods is actually - a kind of "proxy" of - the transformation of the city itself. What you do think? Is that the only way ethnic/migrant entrepreneurship may contribute to the transformation of the city?

    Thanks for sharing your thoughts!

    Christophe Gibout · Université du Littoral Côte d'Opale (ULCO)

    Her work is on african migrant entrepreneurship, of coure

  • Andrew Eckles added an answer in Distillation:
    Does anyone know what you can use, such as an extractor agent, to separate the mixture butanol-ethanol-water?

    We need to separate a mixture in a column distillation using an extractive distillation system.

    Andrew Eckles · U.S. Department of Veterans Affairs

    The choice of solvents is a balance between selectivity and capacity. Isopariffinic type solvents can have very high selectivity and can be used to break water azeotropes but may have lower capacities that other more polar solvents. More polar solvents may have greater capacities and higher extraction efficiencies, but may have more water carryover in the extracted alcohol and more solvent in the aqueous stream which would need to be stripped out and recovered. I have even seen some blends proposed to increase the concentraton of alcolhol in the solvent stream. Years ago, I designed and operated a continous system that fermented ethanol, extracted it, stripped off the dry ethanol, and recycled the solvent. You can probably find good references to this work in early work sponsored the the U.S. Department of Energy.

  • Daniel Wright added an answer in Informal Learning:
    Why are mnemonics not provided to students (low and high education) in information-heavy courses?

    There are loads of mnemonic-techniques out there ranging from method of loci to musical mnemonics. It is my understanding and experience that mnemonics can increase the amount of information learned and prolong the period in which it can be recalled. I think musical mnemonics is a great example since one can easily realize the vast amount of lyrics from regular songs that one can recall. Imagine if these songs were enconded with meaningful information...

    Daniel Wright · ACT Inc.

    Recent versions of the Hilgard Intro to Psychology have a section on how to learn the material based on cognitive science. It is easier to embed this in a psych course sense mnemonics is part of the course content.

  • Dina Hofer asked a question in Mycoplasma:
    Can you recommend a reliable method to detect mycoplasma in cell culture?

    We tested several PCR primers and (very expensive) commercial mycoplasma-kits. Do you know about reliable primers or other self-made methods to detect mycoplasma in cell culture? Thanks in advance. 

  • Nick Cheung asked a question in Membrane Proteins:
    Why exactly are some proteins (particulary membrane protein) toxic to cells?

    I am aware that in expressing membrane protein, it is better to use C41(DE3) or C43(DE3) cells but how exactly does protein induce toxicity to the cell and how does C41 and C43 prevent that from happening?

    Thanks

  • Simon Castro added an answer in Electrophysiology:
    Is there an established reason why some patients show evidence of dual pathway electrophysiology in the AV node, and others not?

    Dual pathway electrophysiology in the AV node is found in 50-90% of patients with AVNRT, and around 10% without AVNRT (see link #1). Since it is the differences in refractory period between the fast and slow pathways which give rise to a discontinuous conduction curve, it is tempting to say that patients with a continuous AV conduction curve have no difference in refractoriness between the fast and slow pathways. However, it has also been suggested that a discontinuous AV conduction curve may be suggestive of longitudinal dissociation of the AV node i.e. a structural change. Is there a definitive answer as to whether it is differences in structure, electrophysiology, or both, which give rise to continuous and discontinuous AV conduction curves? Any references to recent articles would be appreciated.

    Simon Castro · The University of Manchester

    Thanks for your comments and the papers (a couple of which I had not seen before) - most helpful! 

  • Kyle Green asked a question in Factoral Design:
    How robust is ANOVA to deviations from normality?

    I am analysing fish consumption data in a 2 factor design (predator species, 2 levels + prey species, 2 levels). The consumption data (number of prey eaten) is not normally distributed so I have been trying to use GLMs to establish whether there are differences in consumption of the prey species by the 2 fish. Initially, I used a Poisson error distribution and switched to quasi-Poisson error when I found the data to be overdispersed. However, the quasi-Poisson GLM is returning no significance for any factor, despite there being no overlap of error bars when I create a barplot of the same data (indicating that significant differences are indeed present).

    I have therefore tried an ANOVA on untransformed data as some articles in the literature claim that ANOVA is robust to deviations from normality. Would love to hear some thoughts on this to help me decide on how to continue?

    Thank you!

    PS. All analyses are being carried out in R.

  • How strict is the GT-AG intron boundaries?

    From sequence alignments of beetle sequences it is clear that other sequence motifs also indicate intron boundaries. Any recent reviews on this topic?

  • How practical are the operational quantities for Sievert?

    The International Commission on Radiation Protection (ICRP) proposed a set of operational quantities defined to allow for calibration of ionizing radiation protection instruments for measurements to show compliance with the system of protection quantities. These measurable quantities are the ambient dose equivalent, the directional dose equivalent, and the personal dose equivalent.

    An earlier question "What is the difference between Sievert and Gray? A practical question concerning the SI units for ionizing radiation?" addressed the confusion of Sievert and Gray and its use in radiation protection programs. This question is a continuation and addresses the practical aspects of calibrating and interpreting instruments used for radiation protection.

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

    The ICRP asserts it has proposed measurable quantities, but have defined them by calculation. The calculation is ideal and impractical for measurement as a parallel expanded beam of a single energy is not possible to produce. The point of dose is at a depth in a sphere or slab, a location not accessible to an instrument. Actual calibration must be performed free-in-air with a non-uniform beam and with physical constraints that may not be negligible. Calibration is to an instrument that is energy dependent and does not have the backscatter characteristics of a sphere, slab, or human body.

    Radu A. Vasilache · Canberra Packard CE GmbH

    ...sorry, I meant a separate comment.

    We go back to the discussion you opened previously. As both you and Hanno stated, using the Sv both for equivalent and for effective dose makes no sense and creates confusion. The operational quantities - practical or not - are meant to be exctly that: operational, i.e. they should be an instrument for mid-level dosimetry technician that will do some measurements, get a reading, compare it with the administrative limit and move on to taking the measures prescribed by the standards if the case.

    The problem is that the Sv is also a unit of risk when use for effective dose and therefore many people will not interprete the readings only as they should do (i.e. a shielding is correctly made or I followed or not the  radiation protection procedures to avoid un-necessary exposure) but they tend to interprete it in terms of risk, especially if they saw some paper saying "so many Sv.man mean this increase in cancer incidence". In my experience, no matter how hard I tried to explain to the laymen that the operational quantities must not be directly related to risk, but they rather need a further interpretation, I was not succesful. So yes, as both of you have proposed before, a new unit is needed for the operational quantities to separate them clearly from the effective dose.

    That's it, I apologise for beating arround the bush for so long.

  • Kimmo Korhonen added an answer in Linear Regression:
    How do you turn a scatter graph into a linear regression where x becomes Cos2theta instead of time?

    Hello,

    I have no experience with this sort of statistics but hoping to convert some data I've collected into a linear regression so that I can compare mine to some secondary data. 

    The raw data/ scatter graph looks at mean depths of sharks (y axis) over time (x axis). I have this for both the secondary data and mine. 

    In order for me to make a good comparison, I need to transform the hours... the previous work has used cos2theta. 

    Is this something I can do on micrsoft excel? or is there anyother software that can do this? 

    Also as the previous research has looked at depths over 24 hours and mine is only over 9 but shows the same pattern for that time, will this effect the R2  value? 

    I'm trying to learn as much as I can about trig now so any information will be really appreciated!

    I've also created a file (mainly so that I know what I'm trying to do) so I've attached it as t may make more sense to you by seeing the data.

    I know theres a good chance what I'm asking might not work/ sound gibberish but thank you in advance and for reading!

    Zoe 

    Kimmo Korhonen · Geological Survey of Finland

    @Jochen

    First of all, it is not "my" straight line model. Secondly, all the parameters (A, B, C and D) are optimized by the Python script. It produces the following result:

    Second attempt: [ 5.07987235 0.44548775 1.16078858 38.12494774]

    which is equal to the solution in your Excel work book.

    I think you miss the point. The fact that one can fit a cosine model does not make it, in itself, the right choice. I have not read the paper, but the authors might actually have some reason for doing the analysis the way they chose to do.

    @Zoe

    θ is most likely hour transformed into an angle in radians (0:00 = 0 rad, 12:00 = π rad, 24:00 = 2∙π rad). I have not read the paper but you should really understand why the authors chose to use 2∙θ. It may not be meaningful to use 0.3 or 0.375. It probably makes the statistics different.

    If the paper does not provide the reasoning for this (it definitely should), you can always contact the authors and ask them directly.

  • Petre Ianakiev added an answer in RID:
    How can I get rid of primer dimer and non specific bands in a previously optimized PCR reaction?

    I have been following this optimized protocol for amplifying the gene of interest (PCR). Lately the primers have started to give non-specific bands as well as primer dimer. I have tried to do temperature gradient, denature primers, dilute primer concentration.

    I see some improvement but this has decreased the product yield in return, and still few non specifics still remain.

    I have to get sequencing done on my product and believe that these will cause hindrance in sequencing.  Need suggestions for optimizing PCR.

    Petre Ianakiev · Beckman Coulter Inc.

    I believe primer dimers are result of degradation of your primers. If you make dilutions of your primers, would be beneficial to use TE instead of H2O. Now that the damage is done, you might want to re-order the primers with HPLC purification (or better PAGE).

    Good luck.

  • Chelsea Hagan asked a question in Adipic Acids:
    Adipic acid dihydrazide agarose turning slightly yellow with addition of protein lysate?

    I have adipic acid dihydrazide agarose beads I'm using to attach a 3' oxidized (with NaIO4) ssRNA (127 nt) for an RNA affinity column. I'm following a well established protocol--RNase-assisted RNA chromatography G Michlewski - ‎2010. When I add my lysate (in SAME buffer I've pre-equilibrated the column with) the color is fine for a few minutes. However, after ~30 minutes on a rotator at RT, the agarose turns a yellow color.  Importantly, my protocol seems to be working, in that I have similar bands to my UV crosslinking experiments. But it's still driving me nuts.

    Any guesses as to why this is happening?

  • Divaker Choubey added an answer in Clonogenic Assay:
    How can I induce tumorigenesis in normal cell culture?

    I want to transform normal cell into cancerous ones in cell culture. We do not have animal facility to check tumor formation in mice/ rats. so I have Four questions:

    1) How can i convert normal cells into cancerous ones in cell culture? Anyone has experience treating normal cells with Benzo(a)Pyrene/ Aflatoxin B1 like carcinogens and convert cells into cancerous ones?

    2) Are these Chronic treatments (low dose treatments for weeks) or just one time treatments?

    3) In such experiments how do you detect that cells have become cancerous? Does they form colonies/ foci? Does Soft Agar Colony Formation assay do justice here?

    4) What % of normal cells can be transformed into cancerous this way?

    Divaker Choubey · University of Cincinnati

    WI-38 human lung fibroblasts have been immortalized using SV40 virus. The virus targets both p53 and Rb tumor suppressors. However, these two events are not sufficient to acquire the transformed phenotype. Therefore, activated Ras oncogene may be needed to make cells serum-independent, contact inhibition independent, and form colonies in soft agar (all associated with a transformed phenotype). Formation of colonies in soft agar is a requirement for forming a tumor in animals.

  • Abhijit Mitra asked a question in Scientific Community:
    Are we interested in seminar kits and food?

    In recent times, I have noticed that participants are more interested in seminar kits, lunch and inner rather than lectures - It will definitely hurt scientific community, but its my personal feelings.

  • Can anyone explain any alternatives to rotatory evaporator to dry organic liquid from a mixture?

    I want to know any alternative to rotatory evaporator to dry organic liquid from a mixture. As we don't have this equipment in the lab.

    Sir ,

    I would like to know that  are you trying to isolate toxin or any other compound from these solvents ? Pyridine is Water solubule , Ethylacetate can evoparate under vacuume at RT or under flow of dry nitrogen. ....

  • Peter T Breuer added an answer in Ubuntu Linux:
    What does this error mean?

    in the installation of Gravsoft software package on linux ubuntu, this error appears and i cannot understand it

    Peter T Breuer · Birmingham City University

    That's not what's written on the terminal (which is a complaint about trailing data in a certain file .. you need to look at that file and check it out).

    Your log means what it says - python doesn't find some code called "tkinter" (must be an interface to TK/TCL) to run.  Surely you understand that just as well as we!

    Do you care? I would have thought TK was all about launching some graphical user interface, which I wouldn't have cared about if it were me.

    But the right people to talk to are the snaphu authors and users forum .. why post here?

    I would search for a directory called tkinter and install the package it belongs to  if you haven't got it. If you have got it but python does not find it, debug further! Check to see where python is looking, and compare with where it is. Check it is all well-formed, etc.

    Debian "apt-file search" tells me that tkinter seems to be an integral part of python 3 (3.2 - my  debian is ancient now). Are you sure you have the right version of python? If not, installing some graphical pythony stuff might bring it in. But ask in the snaphu forums, or google the error with "snaphu" on the front of the query.

  • Mujeeb Abdullah added an answer in Antenna:
    How can I increase the bandwidth at lower frequencies?

    I am using FR4 substrate with 1.6 mm thickness and 4.6 dielectric constant for a dual band dipole antenna. If there are some techniques to increase the bandwidth at lower frequencies without changing the substrate, please help.

    Mujeeb Abdullah · University of Electronic Science and Technology of China

    I  think  you  should  also  increase  the  hight  of substrate.

  • Matthew Adlam added an answer in Gradient PCR:
    What can I do to have pcr products with A-T rich sequences using genomic DNA as template?

    I have six constructs with the following G-C contents: 29.6%, 23.2%, 27.2%, 24.4%, 27% and 28%. Due to the low G-C content of genes of interest, the Tm of my primers (see attached file) are low; calculated between 45 and 55 °C using the Thermo Scientific Tm Calculator (Taq-based).

    I started off with a gradient PCR using the protocol slated below for all six constructs. I had no product but primer dimers appearing as a thick band below the last band of a 1 kb plus ladder. At the end of the day, I had optimized annealing temperatures between 38 °C and 65 °C (First 38-52°C and then 48-62 °C). I played a little with the extension time (increasing) but no luck

    Component                            50 μl rxn                              Final Conc.
    10X DreamTaq Buf.                  5 μl                                           1X
    2 mM dNTPs                             5 μl                                           200 µM
    1.25 µM Primers mix                 5 μl                                           0.125 µM
    Template DNA                          1 μl                                            2 ng
    Taq DNA Polymerase               0.5 µl                                         2.5 units/50 µl Nuclease-free water                 33.5 µl                                       —

    Cycling conditions

           Step                           Temp                         Time                 Cycles
    1. Initial Denat.                  95 °C                         2 min                 
    2. Denat.                           94 °C                         30 sec

    3. Annealing      38-52°C/48-62 °C (Grad)        30 sec                  
    4. Extension                       68 °C                         4 min

    5. Go to 2                                                                               24X
    6. Final Ext.                      68 °C                           10 min
    7. HOLD                             4 °C —

    I increased the Mg2+ conc. and nothing happened. DMSO won't be my friend because of the low GC content I guess :).

    I checked the conc. of my ordered genomic DNA to 130 ng/μl on the NanoDrop. I decided to increase the concentration by adding up to 100 ng/50 μl Rxn and nothing. I have read here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC145803/ that reducing the extension temperature (to as low as 60 °C) required for PCR amplification of extremely A+T-rich DNA leads to product formation. That did not work. Instead, I had some unspecific product for two of the constructs as well as primer dimers. I have also done a control experiment together to validate the reagents and everything worked very fine with the control. My primer sets (forward and reverse) are mixed in a single-stock aliquot. Could this be the problem?

    Please I will greatly appreciate any proposals. Thanks in advance.

    Matthew Adlam · Icahn School of Medicine at Mount Sinai

    Longer primers....IDT make primers greater than 60 bp (ultramers).  Also my favorite kit for one off PCR cloning needs (as in you only need the product once) I use epicenter MasterAmp kits, especially the extra-long kit,  It comes with 9 buffering conditions and I just about always get a product in about ⅓ of the reactions.  It uses a combination of 3 polymerases including Taq, so some of the ends of your PCR product will have an a-tail.  Just add some more taq/ATP and incubate at 72 degrees after PCR and sub clone into a t-tailed vector (my favorite is the invitrogen PCR2.1)

    Also another thing to try is a slow ramp from your annealing to extension, this gives the polymerase a chance to elongate from your primers, increasing their Tm.

    But, the best thing to do is remake your primers.

    Good luck

  • Federico Luzzati added an answer in Bone Biology:
    Do you have experience of staining blood vessels in murine periosteum?
    I'm trying to stain blood vessels in murine periosteum (whole mount), tried antibodies against CD31, SMA and lectin and in different bones (scal, iliac crest femur). The protocol works well but staining is not deep enough - about 15 um with formaldehyde fixation for 30 min incubation and ~35 um with a mixture of formaldehyde and glutaraldehyde. My goal is to image as deep as ~100 um (periosteum) with confocal microscope.
    Federico Luzzati · Università degli Studi di Torino

    Chek this: http://www.jneurosci.org/content/27/22/5976.long

    Is for the brain, they use gelatin and BSA-rhodamine perfusion

  • Mohamed Alji added an answer in Similarity Measures:
    How to locate the regions of dissimilarity between two images that look almost the same ?

    Suppose I have two images that look almost the same, there is only a slight differences. I would like to locate at least one small region that it is not similar.

    How to do that please ? Until now I have found Bhattacharyya distance, I am still investigating it.

    Mohamed Alji · Université Ibn Tofail

    Hi Jose,

    true it is straightforward, but that is not effective. The slight differences between the two images are sometimes just nuances on gray-scale level. That mean if I substract an image from another, I will get a full image of data and then I have to process it again.

    thank you for the idea, can you elaborate more ;) 

  • For how long you continue clopidogrel post coronary bypass?

    use of clopidogrel post coronary bypass

    Rubin Sylvain · Centre Hospitalier Universitaire de Reims

    Aspirin is not tolered ? why ? Perhaps you could use a very low dosage of Aspirin without any digestive adverse effect (50mg / day). If you use Clopidogrel, itsnot indicated to follow this therapy for the rest of his life because of adverses effects, frequent and possibly  severe. Personnaly I didn't use this therapy for more than 6 months after CABG.

  • Nick Juana asked a question in Bowling:
    How can we conclude that one piston bowl will be better than other piston bowl using CFD analysis ?

    When simulating compression stroke using CFD how can be one piston bowl will be better than other piston bowl. For example one piston head has cylindrical bowl and other has hemispherical bowl. How to differentiate them.  

  • To what extent does CSR(Corporate social Responsibility) is helpful in Public Relations?

    I am trying to seek the role of CSR as a tool of Public Relations in Corporate sector.Kindly suggest any reading, book or Article.Thanks

         Reference of some case study will be a great help.

         
  • Abhishek Kumar asked a question in Abaqus:
    How can I have mesh as shown in the attached image?

    I am using ABAQUS. I am aware of biased mesh and can generate rest of mesh other than the transition (trapezium shaped) elements in width direction. 

  • Gerhard Behrendt added an answer in Polyurethane:
    Can anyone provide me with information about Polyurea resistant paints?

    I want to know about the chemistry of polyurea or polyurethane resistant paint.

    If it is possible please guide me

    Gerhard Behrendt · Technische Hochschule Wildau

    Please, provide information to what resistance you are aiming. There are so many ways to produce polyurethane coatings, e. g. solvent containing, high solids, one component, two component systems, solvenfree systems, aqueous dispersions etc. If you want detailed information you have to define at least the type of application and the type of resistance.

    Polyurea systems are usually two component systems based on isocyanate prepolymers (their design determines properties) and di- or polyamines. By the choice of the composition of the prepolymer and the type of amine you determine the reaction and tack free times and properties. Another way is to you carbamates and perform a trans-amidation with amines in substance or solution. Again, the type of application and desired resistance determine the type of raw material.

    If you want further information on commercial products go to www.nitroil-polyurea.com

  • Sherif Askar added an answer in Lymphoma:
    In cases of of extranodal lymphomas of the upper respiratory airways: what is your regimen after excision?

    After excision and biopsy of extranodal (isolated) lymphomas of the upper airway: what is next? What forms of chemotherapy are given and for how long? What is the mean follow-up period?

    Sherif Askar · Zagazig University

    Dear Colleagues,

    I want to know your institution regimen, in case of extranodal lymphomas (B or T-cell; although i personally agree with Dr Zhukov assumption, as B-cell is more commonly encountered),

    please mention your types and periods of medications;

    Also, do you like to prescribe a therapeutic course of radiotherapy in those cases? 

  • Hans Matsson added an answer in Haploview:
    How can one increase image quality of LD triangle plot in Haploview?

    In haploview I have made an LD plot for the purpose of including it in a manuscript/poster.

    However, the image is very pixelated and of low quality. I cannot see where to increase pixels per inch or similar?

    Is this possible?

    Kind regards/ Jacob 

    Hans Matsson · Karolinska Institutet

    Yes, the software tries to break down line drawings and images sort of "pixel by pixel". You set the threshold for the process. Essentially, you should after this be able to zoom in a lot without losing resolution.

  • Does anyone know a reliable method to extract and clean up difficult matrices like dry spices, hop, avocado etc. for pesticide residue analysis?

    I have tried to work with the QuEChERS method and used different salts, but the recoveries are very poor. The method must operate for more than ~ 600 different pesticides and I work with GC-MS/MS and HPLC-MS/MS.The methode should be practible for routine analysis.

    Marco Volante · A R P A Lombardia

    Dear Cornelia, now i'm not dealing anymore with food analysis, since december 2001, but in the past I was using an internal method, developed from me on the basis of the literature and technologies availables in 1995-2000. First of all if you can operate on  well dried samples, the extraction will give better yelds. This is not necessary in the case of dry spices (already dry matter) but I had, in such a case,  some problems in co-extracting a lot of interferent in such a case. On the other hand, with a matrix with a high fat content like avocado, a purification step with gel permeation chromatography (GPC) was in my experience, necessary.

    The procedure I'm going to describe here may be too complex for low-time consuming routine procedure, but you could modify it, or use it for the most critical matrices. I usually extracted 20 g of vegetable by sonicating them in 40 ml of acetone. Thi for a good extraction. The I added, for drying sample, 40 g of Extrelut and placed this mixture in a 20x6 cm glass column ad fluxed with a nitrogen stream form the bottom. At this point you can try to extract pesticides directly with dichloromethane-acetone 9:1  (in those years - 1995 - I was not yet thinking to substitute DCM with a less harmful solvent .sorry!. But it works very well!!)  2 x 100 ml. Then, concentration of the extract with Rotavapor or Turbovap (N2 stream, air stream) to a desired volume.

    If you work with MS/MS detector probably you will not need a particular cean up. In not, I cleaned up my extract on polar columns SPE.NH2. I collected the DCM extract passed through NH2 cartridge and collected also washing  volumes with acetonitrile. THe concentrate to a final 1-2 ml or desired volume.

    In the case of dried plant extracts I usually extracted 2g of dry matter. The extract was so full of interfering substances that a furter clean up step with Galpermeation Chromatography (Fluid Management System, column and solvents for vgetables/fuit sample).

    In the case of Avocado, GPC (FMI, column and solvent for fat samples) were necessary in order to eliminate fas, as well as for milk, cheese, fish, meat..).

    You could also downolad from ResearchGate my paper "Application of Solid Phase Micro‐Extraction (SPME) to the analysis of pesticide residues in vegetables"  where, for comparison purposes, a section (2.2.1 Multi residue method) is dedicated to the description of  traditional multiresidue method used by us.

    Hoping to have given some useful suggestion, Best Regards. MVolante