Applications

In scientific research, pollen has a wide range of applications. According to Dr. Limi Mao, Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, by extracting and analyzing different pollen deposited in the soil, it is possible to understand which parent plants they came from respectively, and thus infer the environment and climate at that time. In the field of botanical research, pollen mainly provides microscopic reference evidence for systematic taxonomy. More interestingly, pollen evidence can also be applied in criminal investigation cases. Forensic palynology can effectively corroborate the facts of a crime by using pollen spectrum evidence on the suspect's accompanying clothing and at the crime scene. In the field of geological research, pollen has been widely used in reconstructing vegetation history, past ecology, and climate change studies. In archaeological studies exploring early human farming civilizations and habitats, pollen can help scientists understand the history of early human domestication of plants, what food crops were cultivated, etc.    Fig. 1 3D pollen model picture (taken by Dr. Limi Mao, product developed by Dr. Oliver Wilson)   The size of pollen varies from a few microns to more than two hundred microns, which is beyond the resolution of visual observation and requires the use of a microscope for observation and study. Pollen comes in a wide variety of morphologies, including variations in size, shape, wall structure, and ornamentation. The ornamentation of pollen is one of the key bases for identifying and distinguishing pollen. However, the resolution of the optical biological microscope has physical limitations, it is difficult to precisely observe the differences between different pollen ornamentation, and even the ornamentation of some small pollen cannot be observed. Therefore, scientists need to use a scanning electron microscope (SEM) with high resolution and large depth of field to obtain a clear picture of pollen morphological features. In the study of fossil pollen, it is possible to identify the specific plants to which the pollen belongs, so as to more accurately understand the vegetation, environment, and climate information of the time.     The Microstructure of Pollen   Recently, researchers have used the CIQTEK Tungsten Filament SEM3100 and the CIQTEK Field Emission SEM5000 to microscopically observe a variety of pollen.  Fig. 2 CIQTEK Tungsten Filament SEM3100 and Field Emission SEM5000   1. Cherry blossom Pollen grains spherical-oblong. With three pore grooves (without treated pollen, the pores are not obvious), the grooves reach both poles. Outer wall with striate ornamentation.     2. Chinese violet cress (Orychophragmus violaceus) Chinese violet cress pollen morphology is ellipsoidal, with 3 grooves, the surface has a reticulated pattern, and the mesh size varies.     3. Ottelia Pollen grains are rounded, wit...

Drug powder is the main body of most drug formulations, and its efficacy depends not only on the type of drug, but also to a large extent on the properties of the powder that makes up the agent, including particle size, shape, surface properties and other kinds of parameters. The specific surface area and pore size structure of drug powders are related to the properties of powder particles such as particle size, hygroscopicity, solubility, dissolution and compaction, which play an important role in the purification, processing, mixing, production and packaging capabilities of pharmaceuticals.   In addition, the validity, dissolution rate, bioavailability and efficacy of drugs also depend on the specific surface area of the material. Generally speaking, the larger the specific surface area of pharmaceutical powders within a certain range, the faster the dissolution and dissolution rate will be correspondingly accelerated, which ensures the uniform distribution of drug content; however, too large a specific surface area will lead to the adsorption of more water, which is not conducive to the preservation and stability of drug efficacy. Therefore, accurate, rapid and effective testing of the specific surface area of pharmaceutical powders has always been an indispensable and critical part of pharmaceutical research.   Case Study of CIQTEK Application in Pharmaceutical Powder   We combines the actual characterization cases of different drug powder materials to clearly show the methods and applicability of this technology to characterize the physical properties of different drug surfaces, and then make some basic analysis on the expiration date, dissolution rate and efficacy of drugs, and help the pharmaceutical industry to develop with high quality.    The V-Sorb X800 series specific surface and pore size analyzer is a high throughput, fast and economical instrument, which can realize rapid testing of specific surface area of incoming and outgoing finished products, pore size distribution analysis, quality control, adjustment of process parameters, and prediction of drug performance, etc.   Automatic BET Surface Area & Porosimetry Analyzer CIQTEK EASY-V Series     CIQTEK SEMs   1、Scanning electron microscope and specific surface and pore size analyzer in montmorillonite dispersion   Montmorillonite is obtained from the purification and processing of bentonite, which has unique advantages in pharmacology because of its special crystal structure with good adsorption capacity, cation exchange capacity and water absorption and swelling capacity. For example: as API, drug synthesis, pharmaceutical excipients, etc.   Montmorillonite has a laminar structure and a large specific surface area, which can have a strong adsorption effect on toxic substances; it is electrostatically combined with digestive tract mucus proteins and plays a protective and repairing role on the digestive tract mucosa.  ...

Spin trapping electron paramagnetic resonance (EPR) method is a method that combines the spin-trapping technique with the EPR technique to detect short-lived free radicals.     Why Use Spin Trapping Technology?Free radicals are atoms or groups with unpaired electrons formed by the covalent bonding of compound molecules under external conditions such as heat and light. They are widely found in nature.With the development of interdisciplinary disciplines such as biology, chemistry, and medicine, scientists have found that many diseases are associated with free radicals. However, due to their active and reactive nature, the free radicals generated in the reactions are often unstable at room temperature and difficult to be detected directly using conventional EPR spectroscopy methods.    Although short-lived free radicals can be studied by time-resolved EPR techniques or low-temperature fast-freezing techniques, their lower concentrations for most free radicals in biological systems limit the implementation of the above techniques. The spin trapping technique, on the other hand, allows the detection of short-lived free radicals at room temperature through an indirect method.     Fundamentals of Spin Trapping Technology   In a spin-trapping experiment, a spin trap (an unsaturated antimagnetic substance capable of trapping free radicals) is added to the system. After adding the spin trap, the unstable radicals and the trap will form more stable or longer-lived spin adducts. By detecting the EPR spectra of the spin adducts and processing and analyzing the data, we can invert the type of radicals and thus indirectly detect the unstable free radicals.     Figure 1 Principle of spin capture technique (DMPO as an example)     Selection of Spin Trap   The most widely used spin traps are mainly nitrone or nitroso compounds, typical spin traps are MNP (2-methyl-2-nitrosopropane dimer), PBN (N-tert-butyl α-phenyl nitrone), DMPO (5,5-dimethyl-1-pyrroline-N-oxide), and the structures are shown in Figure 2. And an excellent spin trap needs to satisfy three conditions.   1. Spin adducts formed by spin traps with unstable free radicals should be stable in nature and long-lived. 2. The EPR spectra of spin adducts formed by spin traps and various unstable radicals should be easily distinguishable and identifiable. 3. Spin trap is easy to react specifically with a variety of free radicals, and there is no side reaction. Based on the above conditions, the spin trap widely used in various industries is DMPO.     Figure 2 Schematic chemical structure of MNP, PBN, DMPO   Table 1 Comparison of common spin traps     Common Types of Spin-trapping Free Radicals   In spin trapping experiments, the most common ones are O- and N-centered radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), but not all ROS and RNS are free radical...

Spin trapping technique has been widely used in biology and chemistry because it can achieve the detection of short-lived radicals. For spin trapping experiments, many factors such as the time of trapping agent addition, trapping agent concentration, system solvent and system pH can affect the experimental results. Therefore, for different radicals, it is necessary to select the trapping agent and design the experimental scheme reasonably to achieve the best experimental results.   1.Trapping Agent and Solvent Selection   The common O-center radicals are hydroxyl radicals, superoxide anion radicals, and singlet oxygen.   Hydroxyl radicals (∙OH)   For hydroxyl radicals, they are usually detected in aqueous solutions and captured using DMPO, which forms adducts with DMPO with half-lives of minutes to tens of minutes.   Superoxide anion radicals (∙O2-)   For superoxide anion radicals, if DMPO is chosen as the trapping agent, the detection needs to be performed in a methanol system. This is because the binding ability of water and DMPO is higher than that of superoxide radicals to DMPO. If superoxide radicals are detected in water, the binding speed of water to DMPO will be greater than that of superoxide radicals to DMPO, resulting in superoxide radicals not being easily captured. Of course, if the superoxide radicals are produced in large amounts, they may also be captured by DMPO. If one wants to trap superoxide radicals in aqueous solution, BMPO needs to be chosen as the trapping agent because the half-life of adducts formed by BMPO trapping superoxide radicals in aqueous solution can be up to several minutes.   Single-linear state (1O2)   For single-linear state oxygen detection, TEMP is usually selected as the capture agent, and its detection principle is shown in Figure 1. Single-linear state oxygen can oxidize TEMP to form TEMPO radicals containing single electrons, which can be detected by electron paramagnetic resonance spectrometry. Since TEMP is easily oxidized and prone to background signal, TEMP needs to be tested before detecting single-linear state oxygen as a control experiment. Figure 1 Mechanism of TEMP for detecting singlet oxygen     Table 1 Common O-center radical detection trapping agent and solvent selection   2、Addition Time of Trapping Agent         In photocatalytic reactions, when light irradiates the catalyst, the valence band electrons are excited to the conduction band, producing electron/hole pairs. Such experiments generally require the addition of the trapping agent before the light irradiation, and in combination with the in situ light system, the variation of the radical signal with the light irradiation time can be studied, as shown in Figure 2, with different light irradiation times, the ∙OH content generated varies.   Fig. 2 Results of CIQTEK in-situ illumination experiments   In the warming reaction, if the reaction temperature...

Since the 1950s, when Watson and Crick proposed the classical double helix structure of DNA, DNA has been at the heart of life science research. The number of the four bases in DNA and their order of arrangement lead to the diversity of genes, and their spatial structure affects gene expression.In addition to the traditional DNA double helix structure, studies have identified a special four-stranded DNA structure in human cells, the G-quadruplex, a high-level structure formed by the folding of DNA or RNA rich in tandem repeats of guanine (G), which is particularly high in rapidly dividing G-quadruplexes are particularly abundant in rapidly dividing cells (e.g., cancer cells). Therefore, G-quadruplexes can be used as drug targets in anticancer research. The study of the structure of the G-quadruplex and its binding mode to binding agents is important for the diagnosis and treatment of cancer cells.   Schematic representation of the three-dimensional structure of the G-quadruplex.Image source: Wikipedia   Electron-Electron Double Resonance (DEER)   The Pulsed Dipolar EPR (PDEPR) method has been developed as a reliable and versatile tool for structure determination in structural and chemical biology, providing distance information at the nanoscale by PDEPR techniques. In G-quadruplex structure studies, the DEER technique combined with site-directed spin labeling (SDSL) can distinguish G-quadruplex dimers of different lengths and reveal the binding pattern of G-quadruplex binding agents to the dimer.Differentiation of G-quadruplex Dimers of Different Lengths Using DEER TechnologyUsing Cu(pyridine)4 as a spin label for distance measurement, the tetragonal planar Cu(pyridine)4 complex was covalently bound to the G-quadruplex and the distance between two paramagnetic Cu2+ in the π-stacked G quaternary monomer was measured by detecting dipole-dipole interactions to study the dimer formation.[Cu2+@A4] (TTLGGG) and [Cu2+@B4] (TLGGGG) are two oligonucleotides with different sequences, where L denotes the ligand. The DEER results of [Cu2+@A4]2 and [Cu2+@B4]2 are shown in Figure 1 and Figure 2. From the DEER results, it can be obtained that in [Cu2+@A4]2 dimers, the average distance of single Cu2+ -Cu2+ is dA=2.55 nm, the G-quadruplex 3′ end forms G-quadruplex dimer by tail-tail stacking, and the gz-axis of two Cu2+ spin labels in G-quadruplex dimer is aligned parallel.The [Cu2+@A4]2 π stacking distance is longer (dB-dA = 0.66 nm) compared to the [Cu2+@A4]2 dimers. It was confirmed that each [Cu2+@B4] monomer contains an additional G tetramer, a result that is in full agreement with the expected distances. Thus, distance measurements by the DEER technique can distinguish G-quadruplex dimers of different lengths.     Fig. 1 (A) The pulsed EPR differential spectrum (black line) of [Cu2+@A4]2 dimer and its corresponding simulation (red line) (34 GHz, 19 K); (B) After background correction, four phases in a-d DEER time-domain ...

  Significance of cardiac magnetic signal detection The human body's magnetic field can reflect information about various tissues and organs within the human body. Measurement of the human body's magnetic field can be used to obtain information about human diseases, and its detection effect and convenience have exceeded the measurement of the human body's bioelectricity. The size of the heart's magnetic field is on the order of a few tens of pT, which is one of the earliest magnetic fields studied by human beings, compared to the brain's. The atrial and ventricular muscles of the heart are the most important parts of the body. Magnetocardiography (MCG) is the result of the complex alternating bioelectric currents that accompany the cyclic contraction and diastole of the atrial and ventricular muscles of the heart. Compared to Electrocardiogram (ECG), cardiac magnetic field detection is not affected by the chest wall and other tissues, and MCG can detect the cardiac magnetic field through a multi-angle, multi-dimensional sensor array, thus providing more information about the heart and enabling precise localization of cardiac heart foci. Compared to CT, MRI and other cardiac research techniques, magnetocardiography is completely radiation-free. Currently, the technology of Magnetocardiography is becoming increasingly mature, with more than 100,000 clinical applications, which are mainly reflected in the following aspects:   01 Coronary heart disease Coronary heart disease is a common and frequent disease, according to statistics, at present, China's coronary heart disease patients have more than 11 million people. Coronary heart disease is the most common cause of death, and the number of deaths even exceeds the total number of deaths from all tumors. For coronary heart disease, MCG mainly detects myocardial repolarization inconsistency caused by myocardial ischemia. For example, Li et al. measured MCG in 101 patients with coronary artery disease and 116 healthy volunteers. The results showed that the three parameters of R-max/ T-max, R-value, and mean angle were significantly higher in patients with coronary artery disease than in normal people. Among 101 patients with coronary artery disease, the proportions of myocardial ischemia detected by MCG, electrocardiography, and echocardiography were 74.26%, 48.51%, and 45.54%, respectively, which showed that the diagnostic accuracy of MCG in patients with coronary artery disease was significantly higher than that of electrocardiography and echocardiography. This shows that the diagnostic accuracy of MCG in patients with coronary heart disease is significantly higher than that of ECG and echocardiography. Reference：Int. J. Clin. Exp. Med. 8(2):2441-2446(2015) 02 Arrhythmias Arrhythmia is defined as an abnormality of the cardiac impulse at the site of origin, the frequency and rhythm of the heartbeat, and any part of the impulse conduction. According to statistics, the number of arrhythmia pat...

Light, electricity, heat, and magnetism are all important physical quantities involved in life science measurements, with optical imaging being the most widely used. With the continuous development of technology, optical imaging, especially fluorescence imaging, has greatly expanded the horizon of biomedical research. However, optical imaging is often limited by the background signal in biological samples, the instability of fluorescence signal, and the difficulty of absolute quantification, which to some extent restrict its application. Magnetic resonance imaging (MRI) is a good alternative and has a wide range of applications in some important life science scenarios, such as the examination of cranial, neurological, muscle, tendon, joint, and abdominopelvic organ lesions, due to its penetrating, low background and stability characteristics. Although MRI is expected to address the above-mentioned shortcomings of optical imaging, it is limited by low sensitivity and low spatial resolution, making it difficult to apply to imaging at the tissue level with micron-to-nanometer resolution.    An emerging magnetic sensor developed in recent years, the nitrogen-vacancy (NV) center, a luminescent dot defect in diamond, NV center-based magnetic imaging technology enables the detection of weak magnetic signals with resolution up to the nanometer level and is non-invasive. This provides a flexible and highly compatible magnetic field measurement platform for the life sciences. It is unique for conducting tissue-level studies and clinical diagnostics in the fields of immunity and inflammation, neurodegenerative diseases, cardiovascular diseases, biomagnetic sensing, magnetic resonance contrast agents, and especially for biological tissues containing optical backgrounds, and optical transmission aberrations, and requires quantitative analysis.     Diamond NV-center Magnetic Imaging Technology   There are two main types of diamond NV-center magnetic imaging technology: scanning magnetic imaging and wide-field magnetic imaging. Scanning magnetic imaging is combined with the atomic force microscopy (AFM) technique, which uses a diamond single-color center sensor. The imaging method is a single-point scanning type of imaging, which has a very high spatial resolution and sensitivity. However, the imaging speed and imaging range limit the application of this technique in some areas. Wide-field magnetic imaging, on the other hand, uses a tethered diamond sensor with a high concentration of NV centers compared to a single NV center, which has reduced spatial resolution but shows great potential for wide-field, real-time imaging. The latter may be more appropriate for research in the field of cellular magnetic imaging.   Applications of  NV center Wide-field Magnetic Imaging Technology in Cell Research   Application 1: Magnetic imaging of magnetotactic bacteria   The magnetotactic bacterium is a class of bacteria that can m...