ESR Method Research Articles

Intermediate-spin state of Co ions in magnetic and thermoelectric properties of double perovskite Ba2CoNbO6

Double perovskite Ba2CoNbO6, obtained by pyrolysis of nitrate-organic mixtures, was studied by XRD, XRF, DFT, AC/DC-magnetization, specific-heat, thermoelectric, and ESR methods. The sample has cubic symmetry space group Pm3m with a = b = c = 4.0074(11) Å. Deficiency in oxygen ions shows the presence of Co ions in both 3+ and 2+ valency. According to AC-magnetization and specific-heat data, Ba2CoNbO6 demonstrates spin-glass ordering at TSG = 30 K at external field value of 0.1 kOe. This temperature of spin glass transition drops with field power increase down to complete suppression at 10 kOe. The effective magnetic moment determined using the Curie-Weiss approximation is 4.29 μB, which is consistent with the theoretical estimation for Co ions in the intermediate-spin state. The peak at T = 90 K, observed in the temperature dependence of the specific heat and accompanied by a peak in the ESR linewidth, is possibly due to the structural transition at this temperature. The Seebeck coefficient of the compound is S = 4–6.5 μV/K and the band gap obtained within the small-polaron-jump conductivity model is ΔE = 0.284 eV in the temperature range of 350–550 K connected with DFT calculation. An intensity ESR line, related to Co2+ ions, was observed in ESR spectra.

Red‐Emitting Pyrazole Azo Hydrazone and Its Metal Complexes for Photophysical Probing, Latent Fingerprints, Anti‐counterfeiting, and Biological Studies

ABSTRACTThe present paper discusses the synthesis of unprecedented red‐emitting mono‐azo compound pyrazole azo fluorescent tag (PAFT) by a diazotization method, followed by an electrophilic substitution reaction. Further, the metal complex of PAFT is also prepared by refluxing the ethanolic solution of the ligand with the corresponding metal (RuCl3 and C4H6CuO4.H2O) salts under suitable experimental conditions. The synthesized fluorophore PAFT displays intense fluorescence in the aggregate state and has excellent qualities, including high purity, low cost, eco‐friendliness, and good photostability. These unique characteristics of PAFT led to the development of new fluorescence‐based technology for the in situ viewing of latent fingerprints. Various spectroscopic and analytical techniques are used to confirm the structural characteristics of the synthesized compounds, including UV–Vis, FT‐IR, (1H) NMR, HRMS, TGA, VSM, ESR, and powder XRD methods. The potency of the antibacterial activity of the compounds was evaluated. The results revealed that compound PAFT and [Ru(PAFT)Cl3] H2O showed excellent sensitivity at 0.8 μL/mL against the Gram‐positive bacteria Staphylococcus aureus.

Stable Cyclometallated Palladium Complexes of Arylamides: Synthesis, Redox and Anticancer Activities

AbstractAir‐stable cyclometalated palladium(II) complexes with benzamide ligands were synthesized in high yields and characterized by X‐ray diffraction analysis, CVA, 1H NMR, 13C NMR spectroscopy, MALDI‐MS, and ESI‐MS. The electrochemical oxidation of the complexes is reversible in the presence of a quinoline substituent in the ligand and gives Pd (III) species that do not undergo reductive elimination and are detectable by ESR spectroscopy. The complexes showed high cytotoxicity against cervical cancer (M‐HeLa) and duodenal adenocarcinoma (HuTu 80), a human mammary ductal adenocarcinoma line (MCF‐7) and a human lung carcinoma cell line (A549). The possibility of generating reactive oxygen species in solution (such as OH−radicals), which can be responsible for the antitumor activity of the studied complexes, using the ESR method was shown.

Synthesis of anthraquinone-based azo-metal(II) complexes as potent anti-oxidizing agents

The 3-diethylaminophenol (3-DEAP) incorporated anthraquinone mono-azo dye derivative [(E)-1-((4-(diethylamino)-2-hydroxyphenyl)diazenyl)anthracene-9,10-dione] DAAD was synthesized through an electrophilic substitution reaction. The interaction between the -OH functional group and the nitrogen atom of the azo moiety may result in intramolecular proton transfer in the DAAD. DAAD was treated with metal ions such as Co(II), Ni(II), and Cu(II) acetates in a ratio of 2 : 1 revealing an octahedral structure. Many analytical and spectroscopic methods, including UV-vis, FT-IR, (1H and 13C) NMR, HRMS, TGA, VSM, ESR, and powder XRD methods, were used to verify the structural characteristics of the compounds. Additionally, the potency of the in-vitro antioxidant properties of the ligand and its Cu(II), Ni(II), and Co(II) complexes were evaluated; the results revealed that the Co(II) complex showed a maximum percent inhibition of 85 μM against the standard ascorbic acid.

Contribution of coupled ESR/U-series fossil dating to a Paleolithic-Neolithic transition site - Naminan, Southwest China

The coupled ESR and U-series (ESR/U-series) method has been increasingly utilized for dating fossil teeth from Early to Middle Pleistocene hominid sites. One significant advantage of this method is its ability to directly analyze fossil animal or human teeth. However, compared with other radiometric methods such as 14C charcoal dating, U-series carbonate dating, and OSL sediment dating, this dating method is rarely employed for Late Pleistocene or younger sites. In this study, we present an ESR/U-series dating investigation conducted at the Naminan site, a Paleolithic-Neolithic transition (P–N transition) site situated on the Sino-Myanmar border. The ESR/U-series analysis of eleven dental samples yields an age range of 18.1–13.2 ka for the fossils. These obtained ages are generally consistent with the 14C chronology of the site. When dealing with young fossil samples, it was observed that due to relatively low uranium concentration in dental tissues, internal dose rate plays a less significant role compared to external beta and gamma dose rates in the total dose rate of the fossil samples. Consequently, evaluating the dose rate of surrounding sediment becomes a primary source of uncertainty. Additionally, in this study we attempted to employ the standardized growth curve (SGC) and representative dose response curve method for determining Equivalent Dose (DE), which was then compared with values obtained using additive dose method (ADM). Although the precision of DE estimated by two methods are comparatively lower than that of ADM, it demonstrates the potential to efficiently determine a more rational Dmax for irradiation, identify samples with stratigraphic disturbances, and analyze small or valuable fossil specimens.

Extending the ESR and OSL dating comparison on coastal dune deposits from the Wilderness-Knysna area (South Africa)

Our work follows up on the initial methodological ESR dating study by Ben Arous et al. (2022) on several quartz samples from the Plio-Pleistocene to Holocene aeolian coastal dune deposits of the Wilderness-Knysna area (South Africa) that were previously dated by optically stimulated luminescence (OSL). Here, we extend this first ESR-OSL comparison with five additional optically-bleached quartz samples. We used the Multiple Aliquot Additive Dose (MAAD) method to specifically (i) evaluate the influence of the irradiation dose steps on the determination of low De values (<100 Gy) and (ii) obtain finite ESR ages for older samples that sometimes show saturated OSL signals. Following the Multiple Centre ESR dating approach, the Aluminium (Al) and Titanium (Ti) signals (Ti–H and Ti–Li–H, the latter resulting from a mixture of Ti centres) were systematically measured in all samples, and resulting De values and age estimates were compared with the corresponding OSL data. Our results show that for young samples (<50 ka) showing De values of a few tens of Grays (Gy), the use of smaller irradiation steps spaced by < 100 Gy has a noticeable impact on the MAAD dose evaluation from the Ti centres, usually leading to De results closer to the expected values (for 2/3 samples). However, this also makes the ESR measurements somewhat more challenging, with higher experimental uncertainties, lower measurement repeatability and lower goodness-of-fit resulting from the relatively weak Ti ESR intensities, ultimately impacting the robustness of the ESR data collected. In this sense, our study illustrates the limitations of the ESR method to detect very low dose irradiation values < 30 Gy with our experimental conditions (i.e., using MAAD procedure, a standard resonator and a measurement temperature of ∼90 K). On the contrary, it also highlights the greater potential of the Ti–H signal to date Late Pleistocene samples, confirming previous studies. Moreover, our results suggest that the transport and bleaching conditions of these aeolianite deposits may not be ideal for the reset of the radiation-induced Al and Ti ESR signals, which is consistent with the very few existing studies specifically focused on this type of samples, but contrasts with other previous dating applications centered on fluvial environments. Finally, we also provide additional chronological constraints to the Landward barrier complex and Coversands deposits, two of the oldest Plio-Quaternary formations in the Wilderness-Knysna area.

Highly sensitive plate-like Bi2WO6 prepared by simple hydrothermal method

In this study, nanosheet-like Bi2WO6 is successfully prepared with a simple hydrothermal method and annealing step. The crystal structure, morphology, and element distribution of Bi2WO6 are analyzed by XRD, EDX, SEM, TEM, ESR and O2-TPD characterization methods. The results show that the prepare bismuth tungstate has no impurity elements, and the distribution of bismuth, tungsten, and oxygen are very uniform. After a detailed analysis of the sample, we also conduct XPS testing. This test is to further understand the surface composition and chemical state of the sample. The results of the XPS test are very clear, revealing that the vacancy oxygen (Ov) content in the sample is as high as 51.85 %. This also explains why bismuth tungstate has a smooth surface but has a high response to triethylamine. After gas sensing performance testing, it is found that Bi2WO6 has good selectivity and long-term stability towards the toxic and harmful triethylamine. At 220 °C, the detection response value for 100 ppm triethylamine gas is 25.5, with a sensor response time of 15 s and a recovery time of 17 s.

Impurity Ions Mn2+ and Fe3+ as Paired Spin Labels for the Study of Structural Transformations in Phyllosilicates by the ESR Method

Impurity Ions Mn2+ and Fe3+ as Paired Spin Labels for the Study of Structural Transformations in Phyllosilicates by the ESR Method

Antibacterial mechanism and enhancement of antibacterial activity under visible light in Er3+-doped BiOBr

The introduction of oxygen defects in semiconductor electronic structures is considered to be an effective strategy to improve their photocatalytic activity. In this work, rare-earth Er3+−doped BiOBr (Er/BiOBr) with oxygen-rich vacancies (OVs) was prepared via simple hydrothermal method. Compared with pure BiOBr, Er/BiOBr has a narrower band gap and more abundant OVs, which together improve the separation efficiency of photogenerated carriers. The introduction of Er not only creates impurity states between conduction band (CB) and valence band (VB), but also produces more OVs as electron traps. Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were used as evaluation systems for these materials with different Er3+ doping contents. The results showed that under the combined action of ·O2− and H2O2, 2.0% EBB samples with Er3+ doping content of BiOBr showed the best broad-spectrum antibacterial activity, and E. coli and S. aureus were completely inactivated at 0.03 mg ml−1 and 0.05 mg ml−1 concentrations. The surface and interfacial structures of Er/BiOBr samples were studied by XRD, brunauer-emmet-teller method, SEM, TEM and EDX. OVs and photogenerated carrier separation in Er/BiOBr were determined by ESR, PL and photochemical detection methods. More importantly, through the detection of lipid peroxidation and bacterial respiratory chain dehydrogenase activities, the internal and external processes of ROS on bacterial inactivation were determined, and the photocatalytic antibacterial mechanism was summarized. This study for the antimicrobial properties of rare earth ions doped improve photocatalytic materials provides a new train of thought.

Ab Initio Shape of Supramolecular Complexes of Cucurbit[8]uril in Solution Found from Small-Angle X-ray Scattering Data

Previous studies of the spatial structure of the guest–host complexes of macrocyclic cavitands cucurbiturils with a number of nitroxyl radicals by ESR, NMR, and crystallographic methods showed that, in aqueous solutions containing a number of nitroxyl radicals as guest molecules, ordered aggregates in the form of an equilateral triangle, with three guest–host monocomplexes located in its vertices, may arise. We performed experiments on small-angle X-ray scattering of aqueous solutions of guest–host cucurbit[8]uril complexes with a stable nitroxyl radical (protonated tempoamine) and, based on the experimental results, carried out ab initio modeling of the shape of aggregates of complexes in the natural state in solution. The search for models of the shape of aggregates was performed either using no additional information about their structure or assuming the presence of a threefold axis. ESR is applied as an independent method for studying the aggregation of complexes in solution. It is shown that the shape of the particles constituting complexes at high cavitand and guest concentrations in an aqueous solution is close in its parameters to an equilateral triangle, which is in agreement with the known crystallographic and ESR data.

Biocomposites Based on Electrospun Fibers of Poly(3-hydroxybutyrate) and Nanoplatelets of Graphene Oxide: Thermal Characteristics and Segmental Dynamics at Hydrothermal and Ozonation Impact.

In order to create new biodegradable nanocomposites for biomedicine, packaging, and environmentally effective adsorbents, ultra-thin composite fibers consisting of poly(3-hydroxybutyrate) (PHB) and graphene oxide (GO) were obtained by electrospinning. Comprehensive studies of ultrathin fibers combining thermal characteristics, dynamic electron paramagnetic resonance (ESR) probe measurements, and scanning electron microscopy (SEM) were carried out. It is shown that at the addition of 0.05, 0.1, 0.3, and 1% OG, the morphology and geometry of the fibers and their thermal and dynamic characteristics depend on the composite content. The features of the crystalline and amorphous structure of the PHB fibers were investigated by the ESR and DSC methods. For all compositions of PHB/GO, a nonlinear dependence of the correlation time of molecular mobility TEMPO probe (τ) and enthalpy of biopolyether melting (ΔH) is observed. The influence of external factors on the structural-dynamic properties of the composite fiber, such as hydrothermal exposure of samples in aqueous medium at 70 °C and ozonolysis, leads to extreme dependencies of τ and ΔH, which reflect two processes affecting the structure in opposite ways. The plasticizing effect of water leads to thermal destruction of the orientation of the pass-through chains in the amorphous regions of PHB and a subsequent decrease in the crystalline phase, and the aggregation of GO nanoplates into associates, reducing the number of GO-macromolecule contacts, thus increasing segmental mobility, as confirmed by decreasing τ values. The obtained PHB/GO fibrillar composites should find application in the future for the creation of new therapeutic and packaging systems with improved biocompatibility and high-barrier properties.

Microstructure and mechanical properties investigation of carbon/stainless steel composite rod prepared by a special device

On the basis of traditional ESR (electroslag remelting technology) method, a special device is designed in the present study, which combined Electromagnetic induction and Electroslag Remelting technology. The composite rods are successfully made for carbon steel and stainless steel with the device. The microstructure and the mechanical properties of the composites are investigated. The tensile test results indicated that there was high bonding strength between two materials. Aiming to further research about the bonding condition, the microstructure examination is carried. It is discovered that excellent metallurgical bonding between two materials has been achieved, with the thickness of the intermediate layer up to the maximum of 235 μm. It proved that this method is reliable to produce the composite rod, which could obtain high mechanical property, and so far, thicker metallurgical combining layer than any other way.

Synthesis, Spectral Characterization and Biological Evaluation of Glutaric acid based Macrocyclic Complexes

In the presence of divalent transition metal ions in their chloride forms, glutaric acid and o-phenylenediamine were used to design and synthesize a unique series of macrocyclic complexes. The UV-Visible, IR, ESR, and ESI-MS spectroscopy methods were used to analyze these newly designed complexes. In order to evaluate their thermal behavior, TGA analysis was employed. The intended general formula for the produced complexes was [M(L)X2] (L = ligand, X = Cl- and M = Co2+, Ni2+ and Cu2+). The central metal ions are surrounded by octahedral environment. These macrocyclic complexes were tested for their antimicrobial effectiveness against the selected bacterial strains (Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli), as well as fungi strains (Aspergillus niger and Candida albicans) and their efficacy was compared to that of standard drugs Streptomycin and Itraconazole respectively. Moreover, the antioxidant activity of the macrocyclic complexes were also assessed using the DPPH assay.

Chronology analysis of huge landslide based on ESR dating materials on sliding face in carbonate areas of south eastern Tibet

Determining occurrence age is key to chronology analysis of huge landslides. However, in carbonated bedrock areas, it is difficult to carry out geochronological surveys of landslide evolution due to lack of suitable dating materials and methods. In carbonated bedrock areas, the cosmic nuclides 36Cl and 14C dating methods have been used for obtaining the exposed age of bedrock. But intense weathering, erosion and dissolution make it difficult to obtain an accurate total amount of cosmogenic nuclide accumulation, resulting in the dating results being affected greatly by weathering, erosion and dissolution of carbonate rock. Therefore, it is necessary to find new dating materials or methods for determining the occurrence age of landslide in carbonate bedrock areas with little quaternary sediments. In this study, a huge landslide developed in the carbonate bedrock area of south eastern Tibet is introduced briefly, which is named the Qiaojia landslide and blocked the Jinsha River. A thin layer including three obvious recrystallized carbonate sub-layers was formed in the sliding zone, indicating different sliding events. Three recrystallized carbonate samples were then collected for ESR dating research to obtain the age information of the Qiaojia landslide: one occurred 79 ± 8 ka years ago, and the other occurred 60 ± 10 ka years ago, and the third occurred 25 ± 2 ka years ago, which are in general agreement with other studies in the surrounding of the study area. It suggests that recrystallized carbonate on sliding face is suitable for chronologically identifying landslide activity by using ESR method in the carbonate area, especially in the areas with little or no quaternary sediments.

The Phosphinate Group in the Formation of 2D Coordination Polymer with Sm(III) Nodes: X-ray Structural, Electrochemical and Mössbauer Study

A coordination polymer has been synthesized using ferrocene-based ligand-bearing phosphinic groups of 1,1'-ferrocene-diyl-bis(H-phosphinic acid)), and samarium (III). The coordination polymer's structure was studied by both single-crystal and powder XRD, TG, IR, and Raman analyses. For the first time, the Mössbauer effect studies were performed on ferrocenyl phosphinate and the polymer based on it. Additionally, the obtained polymer was studied by the method of cyclic and differential pulse voltammetry. It is shown that it has the most positive potential known among ferrocenyl phosphinate-based coordination polymers and metal-organic frameworks. Using the values of the oxidation potential, the polymer was oxidized and the ESR method verified the oxidized Fe(III) form in the solid state. Additionally, the effect of the size of the phosphorus atom substituent of the phosphinate group on the dimension of the resulting coordination compounds is shown.

Synthesis and structural investigation of o-Vanillin scaffold Schiff base metal complexes: Biomolecular interaction and molecular docking studies

Schiff base metal complexes such as VNPV (VO(IV)), VNPCo (Co(II)), VNPNi (Ni(II)), VNPCu (Cu(II)) and VNPZn (Zn(II)) have been synthesised by using the ligand (VNP) which was prepared by the condensation reaction of o-Vanillin and N-phenyl-o-phenylenediamine. Elemental analysis, UV–visible, FT-IR, ESI-MS, ESR, 1H NMR, XRD, SEM and Cyclic Voltammogram methods were used to evaluate the above metal complexes. The metal center in the complexes is four coordinated by using the tetradentate N2O2 donar Schiff base ligand to form square pyramidal geometry for VO(IV) metal complex and square planar geometry for other metal complexes. The disc well-diffusion method was used on agar plate to assess the in vitro antibacterial activities of the ligand and its metal complexes against bacteria such B. amyloliquefaciens, B. cereus, B. subtilis, S. epidermidis and S. aureus. From the results demonstrate that the metal complexes of the ligand exhibit better antibacterial behaviour on S. aureus bacteria than the other bacterial strains. The antioxidant studies were carried by DPPH free radical scavenging assay method and from the results it is found that the VNPCu complex has better antioxidant activity than the ligand and other metal complexes. Additionally, the spectral techniques like UV–visible absorption, fluorescence and molecular docking methods were used to examine the interactions between the ligand and metal complexes with biomolecules (DNA and BSA). The CT-DNA cleavage activities of metal complexes with CT DNA were examined by gelelectrophoretic method. From the results, the VNPCu complex has only cleave the DNA molecules than the other metal complexes. According to the results of the investigations, the metal complex VNPCu exhibits better interaction with the biomolecules than the free ligand and other metal complexes.

Antifouling CuO@TiO2 coating on plasma-grafted PAA/PES membrane based on photocatalysis and hydrogen peroxide activation.

Because of the small size effect leading to the high bandgap of TiO2 P25, the photocatalytic membrane using this photocatalyst has low antifouling efficiency. This study prepared CuO@TiO2 composite photocatalyst with a lower bandgap than TiO2 P25 and used it as antifouling coatings on the PES membrane with PAA intermediate adhesive layer. PAA was grafted onto the surface of the PES membranes through free radicals generated by the cold plasma treatment of the PES membrane. The composite photocatalysts were characterized by FTIR, SEM-EDS, TEM-EDS, XRD, BET, UV-Vis DRS, XPS, and ESR methods demonstrating high surface area (51.0 m2/g), decreased bandgap, and the formation of active free radicals under UV light irradiation. Under photocatalysis and hydrogen peroxide activation, the degradation of AB260 (acid blue 260) catalyzed by 10%CuO@TiO2 reached about 92% after 60min. Besides, the photocatalytic and antifouling activities of CuO@TiO2/PAA/PES membranes are high and stable over five continuous cycles. The water flux of the modified membrane was not significantly influenced and only decreased about 10% compared to the pristine membrane. In addition, the flux recovery ratios (FRR) of fouled membranes treated by photocatalysis were almost 100%.

Comparison of Automated (ISED) ESR Estimation with Conventional (WESTERGREN) Method for Validation of Automated Results

Background: ESR inspite of being considered as a non-specific heamatological test is widely used for the detection of autoimmune diseases, infections and cancers. Although conventional gold standard methods are considered accurate and authentic but are having few biohazard risks and are more time consuming so are thought to be replaced by automated methods which are less time consuming and not much expensive but need to be validated by comparing them with conventional manual (Westergren) method. Objective: To compare the ESR values by conventional ESR method i.e. Westergren method with automated ESR estimation by ISED (ALCOR) to validate the results obtained by automated method. Study design: A Prospective cross-sectional study Study duration and settings: Study was conducted at Pathology Department Pak Emirates Military Hospital Rawalpindi from November 2021 to April 2022. Material and methods: All samples were processed within 1 hour of venipuncture. Hemolyzed samples were discarded. To separate EDTA sample tubes were taken and 3ml venous blood was collected in each tube respectively. Results: 200 samples in total were used for Westergren's (Manual Method) and ISED's ESR estimates (Automated Method). Mean age of the patients was 50.74 ± 16.84 years range from 8 to 88 years, out of total 54 % patients were male and 46 % were females, 51 % patients from OPD and 49 % were admitted patients Conclusion: The conventional Gold standard method has proven to be more efficient by CV % but p-value calculated individually as well as in all cases was statistically insignificant &gt; 0.05%. Keywords: Automated method, Erythrocyte Sedimentation Rate, Westergren method.

Comparison of alternate erythrocyte sedimentation rate measurement by automated Celltac α+ (MEK 1305) and reference Westergren method

Objectives: Manual Westergren method is routinely used for ESR measurement; however, it has many limiting factors which include inherent and technical factors. Alternate/modified Westergren methods have been devised to overcome the limitations of the manual Westergren method. These new methods must be properly evaluated before introducing in clinical laboratories. Material and Methods: A total of 350 randomly collected Ethylene Diamine Tetraacetic Acid (EDTA) samples from hospitalized and ambulatory patients were assayed parallelly in the recently launched Hematology Analyzer Celltac α+ (MEK 1305) and manual Westergren method. Results of these assays were subjected to statistical analysis using a coefficient of correlation, Passing-Bablok regression, and the Bland-Altman statistical methods and the results of the present study were also compared with 16 selected similar studies published in the past 22 years. Intrarun precision using patient samples and inter-run precision using manufacturer’s controls (MEK-3DN and MEK-3DL) were also determined. Results: The present study revealed a Pearson correlation of 0.9058, mean bias of −6.43, and limits of agreements 17.5–−30.4, between Celltac α+ (MEK 1305) and the reference Westergren method. Intrarun precision using patient samples yielded a coefficient of variation ranging from 0% to 14% and inter-run precision using commercial controls yielded a CV of 9.32% for abnormal (MEK-3DL) control and 13.6% for normal level control (MEK-3DN). Conclusion: With good correlation between Celltac α+ (MEK 1305) and the reference Westergren method, acceptable bias, and limits of agreements, automated Celltac α+ (MEK 1305) with its additional advantages is a valid substitute for the reference ESR method in clinical laboratories.

The Chronology of Early Human Settlement in Three Gorges Region, China—Contribution of Coupled Electron Spin Resonance and Uranium-Series Dating Method

The Three Gorges region (TGR) located in the geographic center of China, is a transition zone between mountain and plain areas, and a probable migration corridor for hominins and other mammals between South and North China. Detailed chronological information of paleoanthropological evidence in this area could help us better understand the human evolution in East Asia. The OSL and U-series dating methods are two conventional dating methods generally adopted to date such sites; however, their applications were limited by the dating range—restricted to several hundred of millennia and ambiguous stratigraphic relationship between the archaeological remains and the dating target materials. Cosmogenic nuclide burial dating of quartzite stone artifacts and coupled electron spin resonance and uranium series dating (ESR/U-series) of fossil teeth have the potential to date Early–Middle Pleistocene hominin sites in Asia and were applied increasingly in China in recent years. However, the application of cosmogenic 26Al/10Be burial dating is limited in TGR because most sites are dominated by limestone, leading to the scarcity of the quartz component. In this case, the coupled ESR/U-series method plays a more important role in the establishment of the chronology of human settlement. In TGR, by using the coupled ESR/U-series method, we have dated seven important Early and Middle Pleistocene hominin settlement sites, including Longgupo, Jianshi, Yunxian, Meipu, Bailongdong, Changyang, and Yumidong sites. Based on our dating results, we propose that hominins were settled in TGR probably from the early stage of Early Pleistocene (∼2.5−2.2 Ma) at the Longgupo site to the late Middle Pleistocene to Late Pleistocene of the Yumidong site (∼274−14 ka) and very likely to spread to other parts of East Asia during this time period. In view of the potential of coupled ESR/U-series dating on fossil teeth from the hominin sites in the TGR, future work may consider the micro damage or non-destructive analysis of enamel fragment with the ESR method and laser ablation ICP-MS techniques that will make possible the direct dating of precious human fossils in China.