Screening - Science topic

You can substitute IPTG with:

AI has shown potential to outperform traditional screening tools in identifying depression, anxiety, and PTSD by analyzing complex patterns in patient data—such as speech, text, facial expressions, and biometric signals. Machine learning models can detect subtle signs often missed in standard assessments, enabling earlier and more accurate diagnoses. However, ethical use, transparency, and clinical validation remain essential for safe and effective implementation.

Yes, you can use the qualitative data from those quantitative studies. In your inclusion criteria, state that you’ll include studies with qualitative insights, even if the overall design is quantitative. For example, mention: "Studies were included if they provided qualitative data on screening barriers, regardless of study design."

When extracting data, focus only on the qualitative parts (e.g., participant experiences). In your review, explain your approach clearly, such as: "Although three studies were quantitative, they provided qualitative data on barriers to screening, which was extracted for this review."

This ensures clarity and transparency in your methodology.

Suthara,

For the proper expression in the plasma membrane an N-terminal tag would be the best with mAb you can buy.

For the activation, a working idea is Galpha16 or proper alternative and then looking for cytoplasmic Ca2+ signals, but you could also try a GTPgamma-35S assay, which directly shows you the activation of any GPCR.

Best, karoly

Establish clear guidelines, support offline activities, arrange screen-free zones, model healthy screen habits, and encourage interactive play and family time to balance children's digital screen time.

I am having the same issue. It doesn't support windows 11?

Playing children with traditional paper-based games offers a valuable opportunity to promote educational development while simultaneously minimizing their use of digital screens.

One effective example is “Spot It! A Mathematical Approach to Offline Games,” which emphasizes the potential benefits of such activities in decreasing sedentary behavior and enhancing cognitive development in children.

If you know for certain that they're the same clone, then why do you need to screen them all? A clone by definition means they're genetically identical.

"The recent rise of generative artificial intelligence (AI) capable of creating scientific images presents a challenge in the fight against academic fraud. This study evaluates the efficacy of three free web-based AI detectors in identifying AI-generated images of western blots, which is a very common technique in biology. We tested these detectors on AI-generated western blot images (n = 48, created using ChatGPT 4) and on authentic western blots (n = 48, from articles published before the rise of generative AI). Each detector returned a very different sensitivity (Is It AI?: 0.9583; Hive Moderation: 0.1875; and Illuminarty: 0.7083) and specificity (Is It AI?: 0.5417; Hive Moderation: 0.8750; and Illuminarty: 0.4167), and the predicted positive predictive value (PPV) for each was low. This suggests significant challenges in confidently determining image authenticity based solely on the current free AI detectors. Reducing the size of western blots reduced the sensitivity, increased the specificity, and did not markedly affect the accuracy of the three detectors, and only slightly improved the PPV of one detector (Is It AI?). These findings highlight the risks of relying on generic, freely available detectors that lack sufficient reliability, and demonstrate the urgent need for more robust detectors that are specifically trained on scientific contents such as western blot images."

You can just update the search with the filter starting from the end of your initial search. (you can add a 6months overlap since some publications can be delayed in their apparition in some web search).

Hello, I'm developing a tool that can help with that, it works with id and color pigmentation areas, one of the tool's modules can help with that. I'll be happy to help.

I have the same problem. Is it due to using browser on phone?

sorry. Dont know

Hi! It looks like an adapter dimer peak at 150 bp. Improve clean-up after adaptor ligation. Use x0.8 of beads, fresh-prepared 80% ethanol, pipette 5-10 times up-down during ethanol cleaning step.

Dear Friday Ameh ,

The term ‘biometrics’ refers to the distinctive physical or behaviouralcharacteristics of an individual that can be exploited for the purpose of electronicidentification and authentication. Among the many types of biometric identifiers,some examples are fingerprints, face traits, speech patterns, and handwritingspeed. Each one of these identities can be used independently as a uniqueidentifier for a certain individual, and they can also be used in conjunction withone another to increase the reliability of identification. Today, biometrics arefinding an increasing number of applications across a wide range of industries.The utilisation of artificial intelligence (AI) in the field of biometrics israpidly developing, with the objective of enhancing the dependability, efficiency,and safety of biometric identification systems. (PDF) AI Based Advancements in Biometrics and its Applications. Available from: https://www.researchgate.net/publication/383551254_AI_Based_Advancements_in_Biometrics_and_its_Applications [accessed Jan 09 2025].

Regards,

Shafagat

Computer vision and artificial intelligence technology can play a pivotal role in creating engaging physical games. Through image recognition by artificial intelligence that enables dynamic gameplay. By taking advantage of computer vision algorithms, I personally created games especially for my nephews using an Arduino controller and through the books I wrote that contain actual experiences in this field, I recommend reading that.

I agree with Michael J. Benedik, the sequential KOs will be far easier to obtain. Also, won't you want the singles as comparisons in your assays?

Dear Salem, for 15N direct observe experiments there are other factors to consider in addition to just sensitivity. The two major issues are heternuclear NOE and relaxation. Some nitrogen atoms can have very long relaxation times. In addition to acquiring a lot of scans you also have to use long relaxation delays. The other factor is heteronuclear NOE. 15N has a negative gyromagnetic ratio, therefor the maximum NOE can be -4. It is possible that the NOE is -1 and that leads to cancellation of the signal. For this reason it is often advised to use inverse gated decoupling (zgig) again with long d1's. Both 15N and 31P have a large shift ranges and the signal might not be where you expect it. If you have seen it in HSQC or HMBC you should know where to look.

In Entangled systems, time has stopped evolving. Meaning literally and clearly, time is ‘frozen’ for an entangled system, regardless of scope and scale.

That is the Ryu-Takayanagi Path selection as it is defined Figuratively “below” the AdS Horizon Surface: the Path (small) l connects points Alice and Bob, who are both at time zero. Meaning, Alice sends a message to Bob at time zero, the Information takes Ryu-Takayanagi Path l, however, the end of that Path l is connected to Bob, who is also and indefinitely at time zero.

Although Ryu-Takayanagi did not originally intend for that to be the case, that is the case. Time is Frozen in the AdS/CFT model for an Entangled system.

Meaning, there is no sequitur description of a “delay” in a system where time is not evolving.

Trying to explain this clearly observable thing with unobservable ‘contraction’ is primitive.

I think maybeVOSviewer?

May I ask what kind of microorganisms are those on the photo ?

You are basically right and jaw crushers are used for coarser grinding and this is true, for example, when crushing stones. However, scale is a material that is ground very easily, produces a lot of dust and when ground in a ball mill will immediately produce a very large amount of too fine powder.

If the task is to obtain mainly particles of 100-200 microns, then a ball mill will cope poorly with this task. In addition, a ball mill is much more expensive than a jaw crusher of the same capacity.

On the other hand, there are small but productive jaw crushers that are designed for crushing to sizes less than 1 mm. When crushing scale in such a crusher, the output of particles of 100-200 microns will be large, and the amount of dust will be much less than after a ball mill. Using a combination of a jaw crusher plus a vibrating screen, you will get a good output of the desired fraction with high productivity and low costs.

Şekil doğru. Işık ekrana çarptığında güçlü olan foton parçacığı ekranda şekli oluşturur. Baskın olan rengin oluşturduğu şekil daha net ve önde görünür. Herhangi bir desenin iki merkez atoma sahip olması diğer dört atomun oluşmasına sebep olur. İlk cevapta anlatılan fırlatılan birinci foton veya elektron diğer şekillerin oluşmasına ortam hazırlar. İkinci foton ise gönderildiği zaman kuvvetli bir bağ oluşur. Bu nedenle kırmızı renk en önde ve daha net olur. Diğer renkler de aynı şekilde kırmızı renk sayesinde birbirine bağlanır. Bu durum gökyüzü olaylarında da olabilir. Örnek yıldızlar ve gezegenler vb. Bu sistem oluşurken artık merkez atom kararlı olur ve istediği gibi hareket edebilir. Sönümleme zamanında renkler zayıfladığı zaman oluşan küp veya dikdörtgen şekiller sırayla görevini yaparak kaybolur. Bu esnada kararlı olan atom en son ayrılır. En zayıf renk desenin üzerinde en son kalır ve sönerek kaybolur. Bu dikkatli incelendiğinde leke bıraktığı görülür.

Hello Ehsan, you could have a try on the Kinase Inhibitor Library from TargetMol which containing 2720 kinase inhibitors/regulators. The price is very competitive. It can be used for research in chemical genomics, pharmacological study, and drug screening for related diseases.

Hi …

Here are some considerations:

Potential Options

_Contact Qiagen:The best approach would be to contact Qiagen directly. They can provide specific guidance on whether any modifications can be made or if there are any recommended workflows for your device.

_Modification: If you're technically inclined, you might explore whether you can modify the reagent tray or worktable to fit standard trays. However, this could void warranties or cause operational issues.

_Alternative Solutions: If conversion is not feasible, consider using the GeneRead QIACube for its intended purpose or investing in a standard QIACube designed specifically for nucleic acid isolation.

I found the solution to the issue. The problem was caused by a small formatting error in the gRNA list file. Specifically, there was a space between the gene name "septin" and the number "5" in the entry for "septin 5". It should be "septin5" without a space. This minor formatting error prevented the data from being processed correctly, leading to the plotting error. It took a long time to identify this issue, but it's resolved now. I'm sharing this in case someone else runs into the same error.

Best,

Hi,

You try https://www.ciidirsinaloa.com.mx/RefFinder-master/ .

You can use two antibiotics at the same time although depending upon the antibiotics there is some synergistic stress incurred by the cells due to having two drugs. So just be aware.

However do you need to both edits at the same time? It might be easier to do them sequentially if possible? Because depending upon efficiency of your experiments the frequency of getting both is certainly going to be lower than getting one.

Emil Aliyev its a nice thoughtful question where yes you are absolutely correct about the activated carbon granules can accumulate dust and impurities over time, reducing their effectiveness. To dedust activated carbon granules, follow these steps:

first can be Sieving: Pass the granules through a mesh sieve or a fine-mesh strainer to remove any lumps and large particles.

Next it can be Air blowing: Gently blow compressed air through the granules to loosen and remove surface dust.

Similarly after airblowing it can be Vibration: Place the granules in a container and vibrate it gently using a vibrating screen or a plate vibrator to dislodge dust particles.

followed by Centrifugation: Spin the granules in a centrifuge to separate dust and impurities from the granules.

and this can also be removed by Rinsing with water: If the activated carbon is water-resistant, rinse it with distilled water to remove any remaining impurities.

and finally one has to look into the Drying: Dry the granules in a low-temperature oven (150°F - 200°F) or under sunlight to remove any moisture.

The quality assessment template in Covidence, a tool used for systematic reviews and research synthesis, may have limitations in humanities and education domains research. While Covidence is widely used in healthcare and medicine, its quality assessment template might not fully capture the complexities and nuances of research in humanities and education.

Humanities and education research often involves qualitative studies, mixed methods, and diverse methodologies, which may not fit neatly into the template's categories. Additionally, the template's focus on bias and risk of bias might not be as relevant in humanities and education research, where context, interpretation, and perspective are crucial.

Researchers in these fields might need to adapt or modify the template to suit their specific needs or use alternative quality assessment tools that better align with their research paradigms.

first and foremost, the phytochemical screening of a plant varies depending on the type of extraction carried out. if you are using the same plant, for example, you expect to have the same constituent depending on the solvent being used. You said you used an aqueous extract of plants, right? Which solvent did you use to prepare the aqueous extract? Please note that Aqueous extract usually contains higher polar solvents because, in the preparation of the solution for extraction, you are adding water to a certain ratio of solvent to water. Mostly, the ideal ratio is 70:30, i.e., solvent 70 and water 30 %. When it comes to the issue of alkaloids, flavonoids, terpenoids, and phenolics, using standard methods such as the Evans and Tresa method, you can check if these phytochemicals are present or not; this is qualitative phytochemical screening. Sometimes we get false positives when we screen for alkaloids in a plant material, so it is best to do a specific extraction for alkaloids and then carry out qualitative phytochemical screening on it to confirm if they are present. I can refer you to one or two of my articles in which I carried out qualitative and quantitative phytochemical screening of a plant.

-Dauda G, Ali BH, Muhammed SY, Muhammad MG, Ismail AM, Muhammad MA, Hassan HS. 2023. Qualitative and quantitative phytochemical profiling of ethnomedicinal folklore plant-Globimetula oreophila. J. Curr. Biomed. Res. 3, 1407-1426.

-Dauda G, Haruna AK, Musa AM, Hassan B, Mohammed IM, Magaji MG. 2016. In-vivo antimalarial activity of ethanol leaf extract of Globimetula oreophila (Hook. F) Danser Azadiracchta Indica. Biol. Environ. Sci. J. Trop. 13, 55–59.

Alexandra Johnson

The white spots selected were all untransposed.

kindly have you cross the solubility parameter, did you get it ? if yes help me so, thanks

Some very interesting antibiotics have been discovered being produced by unculturable soil microorganisms and previously unstudied microbiomes. See, for example, work from the lab of Kim Lewis at Northeastern University.

Sometimes, there is a communication issue between the machine and the laptop and you may need to reset the PCR machine.

However, if it is your touch screen on the pcr machine, we have found you can connect a usb mouse to the front port and use the screen functions that way.

Hope this helps!

As you will be aware, plants are a very rich source of phytochemicals and this will be reflected in your aqueous extract. The IR spectra of your extract will be complex, containing the overlapping spectra of every compound. You will not be able to identify any individual compound with any degree of certainty.

If you want to identify the components of your extract then you need to resort to a Metabolomics type experiment. You need to add in several chromatographic steps and then resort to GC-MS (headspace for volatiles), after appropriate derivatisation, and to LC-MS. The spectra can be searched against various libraries. Even then you will be left with many unknowns.

found that males displayed larger head and neck flexion angles than females, which were associated with the amount of computer use.

hey Paul Shen

sorry to bother you but i have tried a lot and i didn't find the answer yet

I'm trying to use autodock GPU on colab but just for one ligand and and receptor

i find that my protein should be in .maps.fld format

but mine is in PDB or PDBqt could you help me if you find a way ?

Tieu-Tieu Le Phung , it is about art.

"On some level, theorists at a blackboard resemble magicians, philosophers, and athletes. They also have something in common with artists, producing intellectual artworks that seem designed for Instagram feeds. As you walk through the London Institute’s exhibition of blackboards, you’re struck by their austere beauty..."

Are the signals from the protein itself or from something else?

The subtraction doesn't always remove the protein signals completely, and in that case you can use one of the pulse sequences that uses a spin lock to destroy the protein signals. On Bruker systems these are the std pulse sequences ending in .3

If the signals are from something else, you could try to run a cpmg experiment or similar to see what they might be.

To screen data using Diameter at Breast Height (DBH) and age, begin by collecting precise measurements of tree DBH and age requires at least 3 years of data. Establish criteria based on your analysis goals, such as specific age ranges or DBH thresholds. Apply these criteria to filter the dataset, selecting trees that meet the specified conditions. Utilize visualizations like scatter plots to explore the relationship between DBH and age. Conduct statistical analyses, such as correlation or regression, to uncover patterns in the data. Perform quality control checks to ensure accuracy, identifying and addressing outliers. Finally, interpret the results in the context of your research objectives, considering how the relationship between DBH and age aligns with expectations or hypotheses. Adjust these steps according to the unique goals and characteristics of your study.

You could use the Edinburgh Postnatal Depression Scale (EPDS)- https://med.stanford.edu/content/dam/sm/ppc/documents/DBP/EDPS_text_added.pdf

Or if you'd like to just check their subjective wellbeing you could use the Subjective Wellbeing Scale developed by the World Health Organization. I have published an article where I have used this scale.

Here are some notable advancements along with their pros and cons:

1. Dual-Energy X-ray Absorptiometry (DXA):

- Pros: DXA is considered the gold standard for measuring bone mineral density (BMD) and diagnosing osteoporosis. It is widely available, relatively low-cost, and exposes patients to low radiation doses.

- Cons: DXA primarily measures BMD and may not fully capture bone quality and fracture risk. It also has limitations in distinguishing between trabecular and cortical bone.

2. Quantitative Computed Tomography (QCT):

- Pros: QCT provides volumetric BMD measurements and can differentiate between trabecular and cortical bone. It is useful for assessing bone strength and fracture risk prediction.

- Cons: QCT involves higher radiation doses compared to DXA. It is less widely available and more expensive. Additionally, QCT scans may have lower spatial resolution compared to DXA.

3. High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT):

- Pros: HR-pQCT provides detailed three-dimensional imaging of bone microarchitecture. It allows for assessment of trabecular and cortical bone compartments, and evaluation of bone strength and fracture risk.

- Cons: HR-pQCT is limited to peripheral skeletal sites (e.g., wrist or ankle) and is not suitable for central skeletal assessment. It is relatively expensive and less accessible than DXA.

4. Trabecular Bone Score (TBS):

- Pros: TBS is a texture analysis technique applied to DXA scans that provides information about bone microarchitecture. It complements BMD measurements in assessing fracture risk.

- Cons: TBS is an indirect measure of bone microarchitecture and relies on DXA scans. It may not be as informative in certain clinical conditions or when DXA scans are of low quality.

5. Biochemical Markers of Bone Turnover:

- Pros: Measurement of bone turnover markers (e.g., serum levels of osteocalcin or CTX) can provide insights into bone metabolism and response to treatment. They are useful for monitoring bone health and treatment efficacy.

- Cons: Bone turnover markers are influenced by various factors and may not provide a direct assessment of bone strength or fracture risk. Their clinical utility is more limited compared to imaging-based techniques.

Hope it helps: credit AI

I'm not sure, as we will need to analyse the data and write the paper over the next year.

Probably the largest screening programmes worldwide are the cervical cancer screening programmes. There is a wealth of information about the screening programmes and I would start with national programmes such as the UK Cervical Cancer Screening Programme:

as this has a variety of information on the programme and how it works as well as links to recommendations and the research which backs it up. There are also links to the National Screening Committee which makes the recommendations and through that archives of all the research and reports that show how the programme works. Ireland has a similar, if slightly younger, programme which is probably worth a look too, on the basis of your location, and has worked closely with the UK in its development.

There is a wealth of data on cervical screening and it is one of the oldest programmes going and has a screening population of many millions in a country like the UK with a universal healthcare system.

Hope this helps.

Var St. Jeor Thank you. Just to clarify, the microscope that I am using is the FEI Tecnai G2 F30 Field Emission Gun Transmission Electron Microscope

In developed countries, a variety of safety measures ensures a low risk of transfusion-transmitted infections. These safety measures include donor selection (limiting imported and window infections); skin disinfection and diversion bags (limiting bacterial contamination during blood donation); the screening of donations (enabling timely detection of HBV, HCV, HIV, and Treponema pallidum); specific processing (such as leukodepletion, pathogen reduction, and inactivation, which remove or kill certain pathogens); quarantine plasma (preventing window infections); bacterial culturing (detecting contaminated platelets); and post-donation and post-transfusion notification (respectively, enabling donor- and recipient-triggered look-back procedures, which identify infected recipients).

Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5732909/#:~:text=These%20safety%20measures%20include%20donor,)%3B%20specific%20processing%20(such%20as

Please check this "Protein-protein binding site identification by enumerating the configurations"

which may help you.

Hi,

You can find it on the following link :)

Hope that helps!

Best of luck from India!

I think goo more tolerate false positive than tolerating false negatives. Tolerating false negative could be dangerous.

First establish a method (HPLC, then LC-MS) which follows good fundamentals for a series of expected known drugs and metabolites. *You can not develop a method for "unknowns".

Kindly refer my articles for conducting meta analysis.

I have collected articles in ten electronic databases - Springer, Elsevier, taylor and francis..etc., and used PRISMA guidelines.

refer this article

Shamseer, L., Moher, D., Clarke, M., Ghersi, D., Liberati, A., Petticrew, M., ... & Stewart, L. A. (2015). Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. Bmj, 349.

Hi, I do realise this is an incredibly late reply but if you are still looking for resources, I have used the CAFE database.

LoBue, V. & Thrasher, C. (2015). The Child Affective Facial Expression (CAFE) Set: Validity and Reliability from Untrained Adults. Frontiers in Emotion Science, 5.

This is a terrible kit, the hi-fi builder is much better at the job. Gibson kit requires more than 6 hrs or even overnight to get the proper assembly done while cloning multiple fragments. Since you are getting assembly products using the overlap extension PCR you can do some things:

1) amplify the fused overlap PCR product using 5' phosphorylated primers/or phosphorylate them after PCR using T4 PNK and then use it for blunt end cloning.

2) try to amplify the vector and. fused product with homology to each other and gel purify/Dpn1 treat them and then directly transform in dh5a, the e coli joins the homology ends in a recA independent homologous recombination reaction within. (One of the easiest and fastest cloning methods I have used to date.)

The following procedures must be followed when handling serum in order to guarantee the highest level of safety for blood transfusions:

A. Donor and recipient ABO and D groupings

- Both the donor and the recipient should have this determined precisely.

B. Extended donor and recipient red cell phenotyping

- In addition to ABO and D antigens, appropriate anti-sera are used to identify other antigens that can lead to immunological sensitizations and reactions, such as: C, E, c, e, K, k, etc.

C. Receipt serum antibody detection and screening

- Standard cell panels should include group O red cells that have been carefully phenotyped and contain all of the antigens that are known to cause transfusion reactions in the area, including D, C, E, C, E, K, K, etc. Additionally, the panels need to contain both homozygous and heterozygous cells for the phenotyped antigens. To demonstrate the dose impact during the antibody identification method, this is required.

Reference:

Ahmed, S. G. (2022). Transfusion services in tropical Africa: Challenges and prospects from the Nigerian perspective. Niger J Haematol, 3, 1-17.

The use of rapid diagnostic immunochromatographic technique (ICT) methods are prevalent in developing countries, while ELISA and molecular testing are recognized as more widely accepted for their enhanced accuracy. Rapid diagnostic tests for viral infections have been available since the 1990s, primarily designed for emergency diagnostics, home-based testing, and field surveys. Furthermore, in several deprived regions, rapid diagnostic tests are used as a means to identify infections caused by the hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). This method serves as a solution to address the scarcity of financial resources and medical equipment. Nevertheless, a significant issue regarding the utilization of rapid screening tests revolves around the necessity for these tests to demonstrate an acceptable level of sensitivity and a sufficient level of specificity to reduce the occurrence of false results.

Reference: Al-Matary, A. M., & Al Gashaa, F. A. S. (2022). Comparison of different rapid screening tests and Elisa for HBV, HCV, and HIV among healthy blood donors and recipients at Jibla University Hospital Yemen. Journal of Medicine and Life. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9762378/

I remember that several users had problems with this at the time you asked. Has the problem been fixed meanwhile?

Robert Adolf Brinzer

Thanks for your advice!

Because our library is a single sgRNA in lentiGuide-puro plasmid, so we just try the same backbone with a single CD45 sgRNA, but if there is a library containing 2 sgRNA per plasmid, we could try it.

For your second advice, in fact, before proceeding with electroporation Cas9 protein, we performed a drug screening with puromycin.

Thanks again for your valuable comments and look forward to your reply!

Dear Malcolm Nobre I really appreciate every response lead and I'm sorry not to lead a debate so as not to influence new responses. Biomarkers are very interesting, really, but would they allow us to say where the cancer actually is in a molecular stage, let's say (on the tongue? on the soft palate? on the floor?) and how to identify the real location at a stage that biomarkers theoretically allow to identify , at the molecular level or would we have to know that we have a probability of oral cancer and then wait for clinical evidence later to locate the tumor? . Westra explains this issue well. Do other methods in other areas really have great sensitivity or specificity or would it be the approach that facilitates, for example, being able to remove the entire tissue where, in the mouth, we do not have such an approach to remove the entire oral cavity.I really appreciate every direct response about oral cancer screening. who knows, one more question: could it be that many studies no longer confuse screening with diagnosis and brilliant works are lost by a mere confusion of basic concepts? very grateful

for such problems, it's important to contact the covidence support team for assistance.

I have conducted the second method in my research. You may refer to my paper

I'd be emailing the corresponding author of whichever paper describes the sort of dataset that's most relevant to you - for example, someone who has published on "intention to move" vs. muscular response time.

Many journals nowadays require that data be made available upon reasonable request, and I'm sure there are many researchers out there who'd be happy to help you?

for high throughput screening, how about "Establishing cell line" using bone marrow-derived mesenchymal stem cells since they possess both myogenic and osteoblast potential?

Aptamers have a wide range of targets, and the size and solubility of the targets are different. Therefore, the application of SELEX technology to screen nucleic acid aptamers can adopt different specific operation methods. Centrifugal precipitation is often used for aptamer screening of cells, bacteria and viruses, and solid-phase adsorption and elution technology can be used for aptamer screening of soluble small molecules. Specific methods for aptamer screening include the following aspects.

Screening methods based on different fixation media. Nitrocellulose membrane filtration is a commonly used method for protein aptamer screening.

Joshi et al. designed a lateral flow chromatographic device based on nitrocellulose membrane. Combining the device with SELEX screening technology, the authors obtained a high concentration of the outer membrane protein (Omp) of Salmonella typhimurium after 7 rounds of positive screening and 3 rounds of reverse screening. Affinity aptamer 33 and 45 sequences with a detection limit of 10-40 cfu/mL. Gel column is also a common immobilization medium for aptamer screening.

Tang et al. used SELEX technology to screen aptamers with high specificity and high affinity for red bean toxin based on agarose gel resin, and their dissociation constants were as low as several nmol. In recent years, the use of microwell plates as immobilization media to screen aptamers has been widely used. Wang Lifeng et al. screened and obtained a high-affinity aptamer sequence that can specifically bind to carcinoembryonic antigen (CEA) based on microwell plate technology. Studies have shown that this aptamer plays an important role in the early diagnosis, monitoring and treatment of tumors.

Fluorescent magnetic beads SELEX (FluMag-SELEX) technology. FluMag-SELEX is a method for screening fluorescent aptamers by combining the application of magnetic beads and SELEX technology. This method requires a small amount of targets and can directly measure the amount of binding ligands through fluorescence. Kim et al. applied FluMag-SELEX technology to screen five specific aptamers of ibuprofen, a broad-spectrum anti-inflammatory drug. Three of them are specific aptamers for racemic ibuprofen, and the other two can specifically interact with racemic and meso ibuprofen. The ibuprofen aptamer has strong specificity and has no binding effect with ibuprofen analogues and oxytetracycline. Xu et al. used FluMag-SELEX technology to screen specific aptamers for PCBs, with dissociation constants at the micromolar level and good linearity in the range of 0.1 to 100 ng/mL.

Capillary Electrophoresis SELEX Technology (CE-SELEX). There is a certain difference in the charge-to-mass ratio between different components, resulting in a difference in the electrophoretic mobility of the substance, thereby achieving the separation of different components. CE-SELEX can realize the screening of high-affinity aptamers within 2-4 rounds, and is often used to screen macromolecular substances such as proteins, lipopolysaccharides, and polypeptides. For the first time, Yang et al. used CE-SELEX to screen the aptamers of the small molecule substance methylmorpholine. After three rounds of screening, eight high-affinity aptamers were obtained, with dissociation constants ranging from several hundred nM to several uM, two of the sequences can catalyze the metal insertion reaction of mesoporphyrin, and the catalytic strength is 1.7 times and 2 times, respectively. Aiming at the problem of dynamic dissociation equilibrium between aptamers with weaker affinity and target systems, researchers have developed non-equilibrium capillary electrophoresis (NECEEM) of equilibrium mixtures, equilibrium capillary electrophoresis of equilibrium mixtures (ECEEM) and Non-SELEX capillary electrophoresis Electrophoresis technology.

Ashley et al. used Non-SELEX technology to screen the aptamers of catalase. The authors characterized their affinity and specificity by using a fluorescence spectrometer and capillary affinity electrophoresis. The affinity of the protein is as high as 100 times, which also shows its high specificity. The aptamer can be applied to biosensor, immunoblotting and biomarker identification. Ashley et al. screened the aptamers of human leptin protein in a free three-dimensional space environment based on NECEEM and SELEX technology, and its dissociation constant was several hundred nM.

Cell SELEX (Cell-SELEX) technology. The main target substances of this method are cells, bacteria or viruses, etc. During the operation, centrifugation and precipitation methods are used to separate and remove unbound suitable ligands, and then specific aptamer sequences are obtained through thermal dissociation or enzyme digestion.

Liang et al. used Cell-SELEX to obtain 5 DNA aptamers after 35 rounds of repeated screening for living cells infected with rabies virus. Virus titer determination and real-time quantitative reverse transcription PCR experiments showed that the five aptamers screened could inhibit the replication of rabies virus, which provided a possibility for the treatment of rabies infection.

Ninomiya et al. used Cell-SELEX to obtain 12 high-affinity aptamers that specifically bind to human liver cancer cell HepG2 after 11 rounds of repeated screening, with dissociation constants ranging from 19-450 nM. The author analyzed and obtained the secondary structure shared by 12 aptamers, which is closely related to the recognition of HepG2. This method can be screened when the nature of the target is unclear and the binding site is not determined, and it does not require a complicated process for preparing the target.tamer screening of cells, bacteria and viruses, and solid-phase adsorption and elution technology can be used for aptamer screening of soluble small molecules.

There are plenty of relevant articles on Google Scholar - e.g. https://academicjournals.org/journal/AJMR/article-full-text-pdf/15879FE11467.pdf

Keep in mind that a QTL is detected specifically when the offspring are segregating for different alleles of a gene affecting the trait. E.g. if parents A and B are fixed for functionally different alleles, their F2 offspring will segregate for AA, AB and BB combinations of alleles at a QTL with different degrees of disease resistance. When you cross parents C and D, of both parents are homozygous for a resistance allele or if both are lacking a resistance allele, there will be no QTL effect.

I agree with Robert Adolf Brinzer that JM109 is (in theory) suitable for blue white screening. I have used the non-DE3 version often in the past. However it can lose the F' which carries the lacIq lacZΔM15 fairly easily so you may wish to steak the strain on minimal medium without any amino acids. The F' is maintained because it carries the proAB genes to complement the proAB deletion on the chromosome.

Another issue is that while you might need to add IPTG to really produce good color, in doing so you are doing to induce T7 polymerase expression from the DE3 prophage. So this may actually counter select against the colonies you want if you are cloning into a T7 expression system. So be cautious that you may be specifically selecting against the clones you want. That is probably why Promega says to not use it that way.

You would be better off to do the initial blue-white screening in a non-DE3 strain and then when you find the correct plasmid to retransform the DNA. However if you don't have any non-DE3 strains then you might try with just X-gal and no IPTG and you might still be able to see blue/white but more faintly.

Hi there,

Your question is a bit of unclear to me... When you mention enzyme production, do you mean the enzyme produced by the gene conferring resistance or do you mean the product of the gene of interest possibly cloned into the vector?

No,it is already shows polled effect

when will you be submitting your PhD?

you can apply

as you see, it's insoluble

Only advice I can give is to have a background in chemistry so you can identify what chemical groups make sense and to be able to investigate related chemical families or to predict parent compounds. For example there may very little on a glycoside but if you look up the parent compound as an alcohol or methoxy ether you can often find a trove of relevant literature. Read all the papers you can about the annotation for the compound as there can often be non-enzymatic routes to the formation of compounds (especially when ROS is involved). Look up other synonyms for the compound as these are not standardized, especially in older literature. Use KEGG to help visualize the pathways where possible and always doubt the automatic annotations. I have seen nature papers where their "marker" for a cancer type is actually a tropical plant alkaloid only produced in one family of trees from southeast Asia (the patient samples from that study were not even from that region of the world). Also if you think the metabolite is important you must always do an alternative assay to verify that it is the correct annotation.

Hello Xi Su

Yes, you may use Hoechst 33342 for mycoplasma screening.

Hoechst 33342 is a cell permeable fluorescent compound that is able to stain the DNA of eukaryotic as well as prokaryotic cells by binding with high affinity to the minor groove of AT-rich DNA sequences. Both Hoechst 33258 and Hoechst 33342 are very closely related bis-benzimides dyes, and are excited by ultraviolet light at around 350 nm, and both emit blue/cyan fluorescence light around an emission maximum at 461 nm. The key difference between them is that the additional ethyl group of Hoechst 33342 renders it more lipophilic, and thus more able to cross intact cell membranes. Hoechst 33258 is significantly less permeant.

You may use Hoechst 33342 for mycoplasma screening. Please refer to the link below. See page 28.

Hoechst 33342 is commonly used as a DNA binding dye to determine cell cycle status and apoptosis assays.

Best.