Double Conjugate Research Articles

Tetrasubstituted Chromanone Synthesis by a Tandem Oxa‐Michael/Michael Addition Reaction of 2‐Hydroxyacetophenones and Alkynyl Nitriles

An efficient transition metal‐free approach for the synthesis of chroman‐4‐ones via double conjugate additions of 2‐hydroxyacetophenones on alkynyl nitriles utilizing NaH as a base has been realized. This operationally simple protocol offers library of 4‐chromanones in moderate to good yields.

Phosphine-catalyzed (3+3) annulation of cinnamaldehyde-derived Morita-Baylis-Hillman carbonates with dinucleophiles.

The phosphine-catalyzed (3+3) annulation reaction of cinnamaldehyde-derived Morita-Baylis-Hillman (MBH) carbonates with 1,3-dicarbonyl compounds as dinucleophiles has been developed, giving hexahydrochromenone derivatives in high yields with moderate to good diastereoselectivities. The reaction worked through double conjugate addition of 1,3-dicarbonyl compounds to the phosphonium intermediates generated from the cinnamaldehyde-derived MBH carbonates.

Reactivity of Acrylamides Causes Cytotoxicity and Activates Oxidative Stress Response.

Acrylamides are widely used industrial chemicals that cause adverse effects in humans or animals, such as carcinogenicity or neurotoxicity. The excess toxicity of these reactive electrophilic chemicals is especially interesting, as it is mostly triggered by covalent reactions with biological nucleophiles, such as DNA bases, proteins, or peptides. The cytotoxicity and activation of oxidative stress response of 10 (meth)acrylamides measured in three reporter gene cell lines occurred at similar concentrations. Most acrylamides exhibited high excess toxicity, while methacrylamides acted as baseline toxicants. The (meth)acrylamides showed no reactivity toward the hard biological nucleophile 2-deoxyguanosine (2DG) within 24 h, and only acrylamides reacted with the soft nucleophile glutathione (GSH). Second-order degradation rate constants (kGSH) were measured for all acrylamides with N,N'-methylenebis(acrylamide) (NMBA) showing the highest kGSH (134.800 M-1 h-1) and N,N-diethylacrylamide (NDA) the lowest kGSH (2.574 M-1 h-1). Liquid chromatography coupled to high-resolution mass spectrometry was used to confirm the GSH conjugates of the acrylamides with a double conjugate formed for NMBA. The differences in reactivity between acrylamides and methacrylamides could be explained by the charge density of the carbon atoms because the electron-donating inductive effect of the methyl group of the methacrylamides lowered their electrophilicity and thus their reactivity. The differences in reactivity within the group of acrylamides could be explained by the energy of the lowest unoccupied molecular orbital and steric hindrance. Cytotoxicity and activation of oxidative stress response were linearly correlated with the second-order reaction rate constants of the acrylamides with GSH. The reaction of the acrylamides with GSH is hence not only a detoxification mechanism but also leads to disturbances of the redox balance, making the cells more vulnerable to reactive oxygen species. The reactivity of acrylamides explained the oxidative stress response and cytotoxicity in the cells, and the lack of reactivity of the methacrylamides led to baseline toxicity.

An efficient spectral element method for two-dimensional magnetotelluric modeling

We introduce a new efficient spectral element approach to solve the two-dimensional magnetotelluric forward problem based on Gauss–Lobatto–Legendre polynomials. It combines the high accuracy of the spectral technique and the perfect flexibility of the finite element approach, which can significantly improve the calculation accuracy. This method mainly includes two steps: 1) transforming the boundary value problem in the partial differential form into the variational problem in the integral form and 2) solving large symmetric sparse systems based on the combination of incomplete LU factorization and the double conjugate gradient stability algorithm through the spectral element with quadrilateral meshes. We imply the spectral element method on a resistivity half-space model to obtain a simple analytical solution and find that the magnetic field solutions simulated by the spectral element approach matched closely to the exact solutions. The experiment result shows that the spectral element solution has high accuracy with coarse meshes. We further compare the numerical results of the spectral element, finite difference, and finite element approaches on the COMMEMI 2D-1 and smooth models, respectively. The numerical results of the spectral element procedure are highly consistent with the other two techniques. All these comparison results suggest that the spectral element technique can not only give high accuracy for modeling results but also provide more detailed information. In particular, a few nodes are required in this method relative to the finite difference and finite element methods, which can decrease the relative errors. We then deduce that the spectral element method might be an alternative approach to simulate the magnetotelluric responses in two- or three-dimensional structures.

Cyclic sulfones from double conjugate addition of Rongalite

Cyclic sulfones are obtained in up to 92% yield by double conjugate addition of Rongalite (sodium hydroxymethyl sulfinate) to dienones. The major product in each case is the kinetic trans-isomer of the 3,5-disubstituted ketosulfone. Eleven examples, including aryl and alkyl substituted substrates, are reported. The advantages of the method are its experimental simplicity, tolerance for both protic and oxidation-sensitive functional groups, and sterically challenging substrates. The work also significantly expands the scope of Rongalite as a conjugate nucleophile.

Investigating the Impact of Polymer Length, Attachment Site, and Charge on Enzymatic Activity and Stability of Cellulase.

The thermophilic cellulase Cel5a from Fervidobacterium nodosum (FnCel5a) was conjugated with neutral, cationic, and anionic polymers of increasing molecular weights. The enzymatic activity toward an anionic soluble cellulose derivative, thermal stability, and functional chemical stability of these bioconjugates were investigated. The results suggest that increasing polymer chain length for polymers compatible with the substrate enhances the positive impact of polymer conjugation on enzymatic activity. Activity enhancements of nearly 100% were observed for bioconjugates with N,N-dimethyl acrylamide (DMAm) and N,N-dimethyl acrylamide-2-(N,N-dimethylamino)ethyl methacrylate (DMAm/DMAEMA) due to proposed polymer-substrate compatibility enabled by potential noncovalent interactions. Double conjugation of two functionally distinct polymers to wild-type and mutated FnCel5a using two conjugation methods was achieved. These doubly conjugated bioconjugates exhibited similar thermal stability to the unmodified wild-type enzyme, although enzymatic activity initially gained from conjugation was lost, suggesting that chain length may be a better tool for bioconjugate activity modulation than double conjugation.

Near-infrared-induced drug release from antibody-drug double conjugates exerts a cytotoxic photo-bystander effect.

Ideal cancer treatments specifically target and eradicate tumor cells without affecting healthy cells. Therefore, antibody‐based therapies that specifically target cancer antigens can be considered ideal cancer therapies. Antibodies linked with small‐molecule drugs (i.e., antibody–drug conjugates [ADCs]) are widely used in clinics as antibody‐based therapeutics. However, because tumors express antigens heterogeneously, greater target specificity and stable binding of noncleavable linkers in ADCs limit their antitumor effects. To overcome this problem, strategies, including decreasing the binding strength, conjugating more drugs, and targeting tumor stroma, have been applied, albeit with limited success. Thus, further technological advancements are required to remotely control the ADCs. Here, we described a drug that is photo‐releasable from an ADC created via simple double conjugation and its antitumor effects both on target and nontarget tumor cells. Specifically, noncleavable T‐DM1 was conjugated with IR700DX to produce T‐DM1‐IR700. Although T‐DM1‐IR700 itself is noncleavable, with NIR‐light irradiation, it can release DM1‐derivatives which elicited antitumor effect in vitro mixed culture and in vivo mixed tumor model which are mimicking heterogeneous tumor‐antigen expression same as real clinical tumors. This cytotoxic photo‐bystander effect occurred in various types mixed cultures in vitro, and changing antibodies also exerted photo‐bystander effects, suggesting that this technology can be used for targeting various specific cancer antigens. These findings can potentially aid the development of strategies to address challenges associated with tumor expression of heterogeneous antigen.

Double Addition Reactions Involving Vinyl-Substituted N-Heterocycles and Active Methylene Compounds.

A series of conjugate addition reactions have been performed with vinyl-substituted N-heterocycles in acid-catalyzed conversions. Using active methylene compounds, double conjugate addition reactions have been accomplished to provide dipyridyl and related heterocyclic products. These conversions have utilized 1,3-dicarbonyl compounds, cyano esters, a cyano sulfone, and malonyl nitrile as nucleophiles. The Michael accepting groups include vinyl-substituted pyridines, quinoline, and pyrazine. Double conjugate addition reactions have also been accomplished with 2,6-divinylpyridine and related systems.

PSMA-targeted low-molecular double conjugates for diagnostics and therapy.

This review presents data on dual conjugates of therapeutic and diagnostic action for targeted delivery to prostate cancer cells. The works of the last ten years on this topic were analyzed. The mail attention focuses on low-molecular-weight conjugates directed to the prostate-specific membrane antigen (PSMA); the comparison of high and low molecular weight PSMA-targeted conjugates was made. The considered conjugates were divided in the review into two main classes: diagnostic bimodal conjugates (which are containing two fragments for different types of diagnostics), theranostic conjugates (containing both therapeutic and diagnostic agents); also bimodal high molecular weight therapeutic conjugates containing two therapeutic agents are briefly discussed. The data of invitro and invivo studies for PSMA-targeted double conjugates available by the beginning of 2021 have been analyzed.

The Coupling of Structural Ordering Methods similar to the Order in Surat al-Tawasim and Al-Hawamim

I have always caught my attention while I recite the verses of the Holy Qur’an, its miraculous style that was and still is the symbol of eloquence and eloquence, and based on this fact, I liked to stand on one side of the methods of the Holy Qur’an, which is the interrogation, but in the form of conjugation. The research was titled (Rhetoric of Syndication of Similar Interrogative Styles in Surat al-Tawasim and Hawamim). where the research plan required that it fall into two topics: The first topic was titled the double conjugation of similar interrogative styles, as it included eleven places distributed between Suras (poets, bees, the forgiver, and the decoration), and the second topic: it was titled the triple conjugation of similar interrogative styles, and it was unique by Sura one of the wall Alhawwamam which al-jathiya and in one position in saying the Almighty: {Ofroit who took God desires and the bounty of God aware of and seal his hearing and his heart and make his vision blurred it guide him after God, do you not remember the} [Jaathiyah: 23].

Імунно-запальні предиктори розвитку діастолічної дисфункції лівого шлуночка у хворих на ревматоїдний артрит в поєднанні з артеріальною гіпертензією

Hypertension is the most common concomitant disease in patients with rheumatoid arthritis. Diastolic dysfunction of left ventricle is an important predictor of chronic heart failure, which can be asymptomatic for a long time. Therefore, it is advisable to detect diastolic dysfunction of left ventricle as early as possible, which can slow the progression of chronic heart failure. The purpose of the study was to determine the value of lipid peroxidation, endothelial function and systemic inflammatory response markers for diagnostic of diastolic dysfunction of left ventricle and for diagnostic of pericardial effusion in patients with rheumatoid arthritis combined with hypertension. Materials and methods. 93 patients with rheumatoid arthritis in combination with stage II hypertension were studied. The ultrasound examination of heart was performed. The serum laboratory markers of lipid peroxidation, concentration of pro-inflammatory cytokines, markers of endothelial function were determined. Results and discussion. Signs of diastolic dysfunction of left ventricle were found in 79 patients and no signs of diastolic dysfunction were found in 14 patients. It was detected that there was a significant increase of concentration of asymmetric dimethylarginine by 16.3%, interleukin-1β by 35.3%, interleukin-10 by 24.3%, the ratio of interleukin-1β / interleukin-10 by 62.0%, C-reactive protein by 52.6% and there was a significant decrease of total nitric oxide metabolites by 36.9%, nitrires by 37.5% and nitrates by 37.0% in patients with signs of diastolic dysfunction of left ventricle compared to the patients without diastolic dysfunction of left ventricle (p <0.01). It was found that the levels of isolated double bonds, diene conjugates, diene ketones, schiff bases and malonic aldehyde in patients with diastolic dysfunction of left ventricle were significantly higher by 24.4%, 25.2%, 20.4%, 17.6% and 21.4% respectively compared to the corresponding markers in patients without signs of diastolic dysfunction of left ventricle (p <0.01). The levels of vitamin A, vitamin E and catalase in patients with diastolic dysfunction of left ventricle were significantly lower by 18.2%, 27.4% and 13.4% compared to the corresponding markers of patients with normal left ventricle diastolic function (p <0.01). The highest predictor value for the diagnostic of diastolic dysfunction of left ventricle was detected in interleukin-1β area under the ROC curve 0.882, sensitivity 72.15% and specificity 100%, 95% CI [0.798-0.939] at the optimal distribution point >9.67 pg/ml and in asymmetric dimethylarginine area under the ROC curve 0.879 sensitivity 75.95% and specificity of 100%, 95% CI [0.795-0.937] at the optimal distribution point >0.715 μmol/l. In 17 (18.28%) patients, the effusion in the pericardial cavity was detected. It was detected that there was a significant increase of isolated double bonds by 18.65%, diene conjugates by 19.73%, diene ketones by 25.25%, schiff bases by 20%, malonic aldehyde by 26.76% and there was a significant decrease of vitamin A by 38.4%, vitamin E by 55.4% and catalase by 37.2% in patients with effusion in the pericardial cavity. The significant increase of asymmetric dimethylarginine was detected by 25.25%, interleukin-1β – by 52.24%, interleukin-10 – by 15.76%, the ratio of interleukin-1β / interleukin-10 – by 38.86% and C-reactive protein – by 26.9% in patients with effusion in the pericardial cavity. In addition, patients with cavity effusion have significant decrease of nitric oxide metabolites by 25.0%, nitrires by 30.0% and nitrates by 11.11% compared to the patient without effusion. The highest predictor value for the detection of effusion in the pericardial cavity was found in asymmetric dimethylarginine area under the ROC curve 0.913, 95% CI area under the ROC curve [0.836-0.961] at the optimal distribution point >0.841 μmol/l, sensitivity 94.12% and specificity 85.53%. Conclusion. The markers, which have the highest prognostic value for diagnostic of diastolic dysfunction of left ventricle in patients with rheumatoid arthritis combined with hypertension, are interleukin-1β and asymmetric dimethylarginine. In addition, asymmetric dimethylarginine has the highest predictor value for detecting fluid in the pericardial cavity

Enantioselective Total Synthesis of (+)‐Garsubellin A

AbstractGarsubellin A is a meroterpene capable of enhancing the enzyme choline acetyltransferase whose decreased level is believed to play a central role in the symptoms of Alzheimer's disease. Due to the potentially useful biological activity together with the novel bridged and fused cyclic molecular architecture, garsubellin A has garnered substantial synthetic interest, but its absolute stereostructure has been undetermined. We report here the first enantioselective total synthesis of (+)‐garsubellin A. Our synthesis relies on stereoselective fashioning of a cyclohexanone framework and double conjugate addition of 1,2‐ethanedithiol that promotes aldol cyclization to build the bicyclic [3.3.1] skeleton. The twelve‐step, protecting group‐free synthetic route has enabled the syntheses of both the natural (−)‐garsubellin A and its unnatural (+)‐antipode for biological evaluations.

Enantioselective Total Synthesis of (+)-Garsubellin A.

Garsubellin A is a meroterpene capable of enhancing the enzyme choline acetyltransferase whose decreased level is believed to play a central role in the symptoms of Alzheimer's disease. Due to the potentially useful biological activity together with the novel bridged and fused cyclic molecular architecture, garsubellin A has garnered substantial synthetic interest, but its absolute stereostructure has been undetermined. We report here the first enantioselective total synthesis of (+)‐garsubellin A. Our synthesis relies on stereoselective fashioning of a cyclohexanone framework and double conjugate addition of 1,2‐ethanedithiol that promotes aldol cyclization to build the bicyclic [3.3.1] skeleton. The twelve‐step, protecting group‐free synthetic route has enabled the syntheses of both the natural (−)‐garsubellin A and its unnatural (+)‐antipode for biological evaluations.

Wavelet Nyström fast numerical algorithm for the integral equation in scattering problems

We present a fast Nyström algorithm to solving the inhomogeneous Lippmann– Schwinger equation for scattering wave field problems. This algorithm transforms the discrete matrix of the linear integral operator into a sparse matrix utilizing the compression property of the wavelet transform. The sparse linear equations are solved by the double conjugate gradient method. In the numerical part, we verified the feasibility and effectiveness of our method by modeling the wave field for a synthetic model.

Designing for conjugate addition: an amine functionalised quinone anolyte for redox flow batteries

Double conjugate addition leads to an increased stability and increased voltage for this amine functionalised quinoidal anolyte designed for basic aqueous redox flow batteries, suggesting that such a reaction does not always lead to degradation.

The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress.

To improve sulfuric acid recovery from sodium sulfate wastewater, a lab-scale bipolar membrane electrodialysis (BMED) process was used for the treatment of simulated sodium sulfate wastewater. In order to increase the concentration of sulfuric acid (H2SO4) generated during the process, a certain concentration of ammonium sulfate solution was added into the feed compartment. To study the influencing factors of sulfuric acid yield, we prepared different concentrations of ammonium sulfate solution, different feed solution volumes, and different membrane configurations in this experiment. As it can be seen from the results, when adding 8% (NH4)2SO4 into 15% Na2SO4 under the experimental conditions where the current density was 50 mA/cm2, the concentration of H2SO4 increased from 0.89 to 1.215 mol/L, and the current efficiency and energy consumption could be up to 60.12% and 2.59 kWh/kg, respectively. Furthermore, with the increase of the volume of the feed compartment, the concentration of H2SO4 also increased. At the same time, the configuration also affects the final concentration of the sulfuric acid; in the BP-A-C-BP (“BP” means bipolar membrane, “A” means anion exchange membrane, and “C” means cation exchange membrane; “BP-A-C-BP” means that two bipolar membranes, an anion exchange membrane, and a cation exchange membrane are alternately arranged to form a repeating unit of the membrane stack) configuration, a higher H2SO4 concentration was generated and less energy was consumed. The results show that the addition of the double conjugate salt is an effective method to increase the concentration of acid produced in the BMED process.

Design, Synthesis, and Targeted Delivery of Fluorescent 1,2,4-Triazole-Peptide Conjugates to Pediatric Brain Tumor Cells.

Most of the chemotherapeutics and drug-delivery models pose serious health problems and several undesirable side effects due to nonspecificity, lack of proper targeting system, and their large sizes. The rational design and synthesis of target-specific chemotherapeutics are highly important. This research work is focused on the rational design, synthesis, and anticancer studies of fluorescent 1,2,4-triazole–peptide conjugates for the development of target-specific anticancer drugs. Three novel 1,2,4-triazole derivatives: 4-(4-fluorobenzylidenamino)-3-hydrazino-5-mercapto-1,2,4-triazole (4FBAHMT, 2a), 4-(3,4,5-trimethoxybenzylidenamino)-3-hydrazino-5-mercapto-1,2,4-triazole (TMOBAHMT, 2b), and 4-(4-benzyloxy-2-methyloxbenzylidenamino)-3-hydrazino-5-mercapto-1,2,4-triazole (4BO2MOBAHMT, 2c) were synthesized after screening through molecular docking procedures. The docking studies were performed between ligand molecules and αvβ6 integrin protein. Fluorescent carbon nanoparticles (CNPs, 3) were conjugated with 1,2,4-triazole derivatives (2a–c) and l-carnosine (LC) dipeptide to get their corresponding conjugates (4a–c). The title double conjugates were characterized by spectroscopic (UV/vis spectroscopy, fluorescence spectroscopy, and FTIR spectroscopy) and microscopic (scanning electron microscopy, transmission electron microscopy, and atomic force microscopy) techniques. In vitro efficacy of fluorescent 1,2,4-triazole–peptide conjugates was investigated against two pediatric brain tumor cell lines (CHLA-200 & SJGBM2) and human embryonic kidney cell line (HEK293 as a control) by employing cell proliferation assay/MTS assay and fluorescence microscopy. 1,2,4-Triazole derivatives and their conjugates showed potent and selective anticancer activity against CHLA-200 and SJGBM2 cell lines. Cell proliferation assay and fluorescence microscopy results revealed that conjugates were more highly selective and cytotoxic than control drug temozolomide (TM) against both cell lines. CNPs are highly biocompatible and the quantum-sized conjugates were nontoxic for normal embryonic kidney cell line (HEK 293). The experimental results of MTS bioactivity assay and fluorescence microscopy were in close agreement with the theoretical results of molecular docking studies.

Pd-Catalyzed Cross-Coupling Reactions Promoted by Biaryl Phosphorinane Ligands

We report the use of biaryl phosphorinanes as ligands for Pd-catalyzed cross-coupling reactions. A modular synthesis was developed that employs a double conjugate addition of primary biaryl phosphines into 1,1,5,5-tetraalkyl penta-1,4-diene-3-ones. Notably, this synthesis does not require the use of copper, a known contaminant in structurally related biaryl phosphane ligands. Using the synthetic strategy described above, we synthesized a library of biaryl phosphorinanes, varying their substitution about phosphorus and the steric and electronic nature of the biaryl motif. We then benchmarked their performance as ligands in Pd-catalyzed cross coupling reactions such as aryl sulfonamidation, aryl alkoxylation, and aryl amination in the presence of soluble organic bases. In each reaction studied, many ligands outperformed biaryl phosphanes known to promote the given transformation. Detailed substrate scopes were determined using high-throughput screening technology. Several biaryl phosphorinanes and their cor...

Double-arc harmonic gear profile design and meshing analysis for multi-section conjugation

Harmonic gear with double-circular-arc tooth profile has great advantage in the meshing performance. However, only the single cross section meshing or the adjustment of the flexible gear structure is considered to design the conjugate profile in the current research, which leads to the increase of the machining difficulty and is not consistent with the actual working condition of the harmonic gear transmission. Considering the cone deformation of the flexible gear shell, in the direction perpendicular to the axis, the conjugate of the flexible gear teeth is different from that of the rigid gear. Therefore, based on the envelope theory, a double circular arc tooth profile of rigid gear can be designed to achieve multi-section conjugation. Then MATLAB programming is used to simulate the flexible teeth in multi-section. At the same time, according to the assembly simulation, it is shown that the different parts of the flexible gear are engaged with the rigid gear continuously in the meshing process. The results show that on the premise of not adjusting the structure of the gear, this method is more consistent with the actual working condition of the harmonic gear compared with the method of only designing the tooth profile of the middle section conjugate. During the meshing process, there is a double conjugate phenomenon in some regions. By means of parameter adjustment, effective conjugation can be realized in a wider range. When the wave generator cam rotates 67.13°, the tooth profile of the middle section is separated from the rigid gear, and the pairs of meshing teeth are increased and the load capacity is strong. Through the finite element analysis, the dynamic characteristics of the harmonic gear device under normal working conditions are studied, and it is proved that the design parameters of the device can fully meet the strength requirements. A prototype of the double circular arc harmonic gear reducer is manufactured. And by means of assembly and dynamic performance test, the accuracy error of return is 105.2 s. The continuous conjugate meshing with multiple sections can improve the stability and bearing capacity of the transmission and is suitable for actual production and processing. The continuous conjugate meshing with multiple sections can improve the stability and bearing capacity of the transmission, and this is suitable for actual production and processing of rigid gear.

Domain decomposition based integral equation modeling of 3-dimensional topography in frequency domain for well electromagnetic field

As an efficient geophysical exploration technology, well electromagnetic method is particularly applicable to oil and gas exploration in China's complex terrain areas (deserts, mountains, etc.). A serious influence of topographic relief area on the electromagnetic response of well is inevitable but challenging. To the best of our knowledge, there is no literature on modeling the electromagnetic response of three-dimensional (3D) topography with well electromagnetic method. Based on the domain decomposition, an integral equation method is presented to simulate the electromagnetic response of 3D topography in frequency domain via the well electromagnetic method. Compared with the finite difference and finite element method based on partial differential equation, this method is very efficient in simulating topographic response without huge computation or truncation boundary error accumulation or special boundary condition requirements. Firstly, an induction coefficient is defined according to the topographic relief situation. Then the computational domain consisting of the target body, background medium and 3D topography is divided into reference model, background medium and the distribution of target body medium area. According to the characteristics of each sub-region, Anderson algorithm is an analytic solution based on Gaussian filtering, which is used to provide the primary field from the excited sources in surface. And then, the stable double conjugate gradient-fast Fourier transform is incorporated into integral equation algorithm to obtain the fast 3D terrain shaft frequency domain electromagnetic responses. By comparing the calculation results using the new algorithm presented in this paper with the analytical solutions of Anderson algorithm for half-space model with surface electromagnetic method, the precision and the efficiency of this new algorithm are demonstrated. And the ability to model the electromagnetic responses of 3D topography is shown by comparing with the published results of 3D boundary integral equation. Thus, the high accuracy and high efficiency of the new algorithm presented in this paper are validated. Finally, the influence of 3D valley topography on electromagnetic field response of surface to borehole electromagnetic (SBEM) observation system is presented and analyzed. It is observed that the response of SBEM is seriously disturbed by the field of 3D valley topography which is necessarily removed. The research results presented in this paper are of significance for guiding the identification and correction of electromagnetic topographic effect from 3D SBEM.