SOC Level Research Articles

Carbon Budgeting of a Long-term Rice-rice Cropping Sequence in the Typic ustipsamments of Kerala, India

A judicious management practice to improve the soil's organic carbon level and soil fertility is essential for agricultural and environmental sustainability. The present study was undertaken to assess the long-term effect of various management practices on soil carbon dynamics and agricultural sustainability by computation of indices like carbon pool index (CPI), carbon lability index (CLI), carbon management index (CMI), critical carbon input and carbon budgeting. CMI has been used as a more sensitive indicator to evaluate capacity of a management practice to promote soil quality. Sensitivity index was used to determine the degree of changes in each carbon fraction due to management practices. The study was carried out in a permanent manurial trial plot started in 1964 under a long term rice-rice cropping sequence in Kerala. Based on the results obtained, integrated application of NPK fertilizers along with FYM showed significantly higher carbon indices, increased soil carbon fractions, and carbon sequestration compared to other management practices. The study revealed that applying organics coupled with inorganic fertilizers will manage the SOC level and result in enhanced soil fertility, productivity, and agricultural sustainability.

Influence of soil pH and organic carbon content on the bioaccessibility of lead and copper in four spiked soils

Exploration of the association between heavy metal bioaccessibility (BAc) and soil properties is essential for rationalization of risk assessment and remediation of contaminated soil; however, the high complexity of soil systems often yield conflicting outcomes. To avoid erroneous conclusions, individual comparisons of soil properties is essential. Herein, we determined the changes in the BAc of Pb and Cu with the variation in soil pH and SOC content using Unified Bioaccessibility Research Group of Europe method, and validated these findings with in vivo mouse bioassays. Results indicated that the BAc of Pb and Cu in gastric and intestinal phases decreased by 1.76%–3.92% and 0.90%–3.27%, and by 0.41%–6.01% and 0.67%–1.59%, respectively, with every unit increase in soil pH. Furthermore, with every 1% increase in the absolute content of SOC, the BAc of Pb and Cu decreased by 4.04%–13.94% and 4.01%–34.7%, and by 8.98%–30.15% and 9.58%–20.03%, respectively. The in vivo bioassays results confirmed decrease in Pb concentrations in the liver, kidney, and blood of mice with the increase in Ferralosol pH and SOC content. These findings revealed that the health risks associated with accidental exposures to Pb- and Cu-contaminated soils with high pH and SOC level were relatively low, and the consistent in vivo and in vitro results for the BAc of Pb and Cu suggest the requirement for a swift and simple approach for assessing the risks of heavy metal contaminated soils. Thus, this study enhanced our understanding of the variations in risk assessments with soil properties of Pb- and Cu-contaminated soils, highlighting the role of soil characteristics in health risk assessment and remediation of contaminated soils.

Core microbial taxonomies that maintain high organic carbon content in upland soil

The accumulation of soil carbon (C) is crucial for the productivity and ecological function of farmland ecosystems. The balance between microbial carbon dioxide (CO2) emission and fixation determines the sustained accumulation potential of C in soil. Microorganisms involved in this process are highly obscure, thus hindering identification and further application of microorganisms with fertile soil function. In this study, a series of typical upland farmland soils were collected from 29 regions and their microbial community structure and soil C fractions were analyzed. Additionally, the rates of CO2 emission and fixation in each soil were measured. The results showed that the correlation between soil CO2 emissions and the SOC concentration was logarithmic, while that between CO2 fixation and SOC was linear. Bacterial and fungal diversity showed an upward trend with increasing soil C, and their α diversity was significantly correlated with CO2 fixation, but not correlated with CO2 emission. Fungi were more associated with soil C than bacteria, and the strength of linkage with soil C varied among the different phyla of microorganisms. Furthermore, the core microbial taxa in soils with low, medium and high SOC levels were identified by discarding redundant amplicon sequence variants, and their community differentiation was significantly driven by soil CO2 emission and fixation based on Mantel analysis. The high abundance of Chloroflexi, Nitrospirota, Actinobacteria, and Mortierellomycota in core taxa might indicate a high level of SOC level. This study highlights that SOC fluctuations are mainly driven by the core microbial taxa, rather than all microbial taxa in the agricultural system. Our research sheds light on the targeted regulation of the soil microbial community structure in upland farmland for soil fertility enhancement.

Post-marketing safety concerns with palbociclib: a disproportionality analysis of the FDA adverse event reporting system

ABSTRACT Objectives To explore the association between palbociclib and related adverse events (AEs) in the real world through U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) database. Methods The signal strength of palbociclib-related AEs was done by disproportionality analysis. Clinical priority of palbociclib-related AEs was scored and ranked by assessing five different features. Outcome analysis, time to onset analysis, dose-report /AEs number analysis, and stratification analysis were all performed. Results There were 61,821 ‘primary suspected (PS)’ reports of palbociclib and 195,616 AEs associated with palbociclib. The four algorithms simultaneously detected 18 positive signals at the SOC level, and 65 positive signals at the PT level. Bone marrow failure, neuropathy, peripheral, pleural effusion, myelosuppression, pulmonary edema, and pulmonary thrombosis were also found to have positive signals. Gender (female vs male, χ2 = 5.287, p = 0.022) and age showed significant differences in serious and non-serious reports. Palbociclib-related AEs had a median onset time of 79 days (interquartile range [IQR] 20–264 days). Conclusions The study identified potential Palbociclib-related AEs and offered warnings for special AEs, providing further data for palbociclib safety studies in breast cancer patients. Nonetheless, prospective clinical trials are needed to validate these results and explain their relationship.

The organic carbon‐to‐clay ratio as an indicator of soil structure vulnerability, a metric focused on the condition of soil structure

AbstractThe soil organic carbon to clay ratio (SOC:clay) is a metric used in soil quality management. In Switzerland and the United Kingdom, for example, threshold values for SOC:clay ratios have been determined to indicate very good (>1:8) to degraded (<1:13) soil structures. A recent article in Soil Use and Management by Poeplau and Don, however, suggested that this metric is ‘strongly biased and misleading’, based on their observation that German sandy soils and heavy clay soils tend to show very high and very low SOC:clay ratios, respectively. An alternative metric was proposed based on the ratio of actual SOC to expected SOC level for a considered area. We offer a commentary on the proposal, arguing that because soil structure quality is overlooked by the approach, it fails to provide appropriate SOC levels for soil health and could lead to soils with highly depleted SOC being classified ‘good’. The SOC:clay ratio, on the other hand, does address soil structure condition, providing a structure vulnerability index, a key function independent of local soil management conditions. When soils are found to have high structure vulnerability, as indicated by the SOC:clay ratio, the cropping practices at the site should be investigated and ways to increase the SOC content considered. Structure condition threshold values may only need to be reassessed if it is shown that the average structure quality observed is not in conformity with the present thresholds, which would be expected for some soils, such as Andosols.

The coexistence of high piezoelectricity and superior optical absorption in Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) monolayers.

Bismuth chalcogenide and its derivatives have been attracting attention in various fields as semiconductors or topological insulators. Inspired by the high piezoelectric properties of Janus Bi2TeSeS monolayer and the excellent optical absorption properties of the Bi2X3 (X = Te, Se, S) monolayers, we theoretically predicted four new-type two-dimensional (2D) monolayers Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) using the first principles combined with density functional theory (DFT). The thermal, dynamic, and mechanical stabilities of Janus Bi2X2Y monolayers were confirmed based on ab initio molecular dynamics (AIMD) simulations, phonon dispersion, and elastic constants calculations. Their elastic properties, band structures, piezoelectric, and optical properties were systematically investigated. It was found that Janus Bi2X2Y monolayers have a typical Mexican hat-shaped valence band edge structure and, therefore, have a ring-shaped flat band edge, which results in their indirect band gaps. The results show that Janus Bi2X2Y monolayers are semiconductors with moderate band gaps (0.62-0.98 eV at the HSE + SOC level). After considering the electron-phonon renormalization (EPR), the band gaps are reduced by less than 5% at 0 K under the zero-point renormalization (ZPR) and further reduced by approximately 10% at 300 K. Besides, Janus Bi2X2Y monolayers also exhibit excellent optical absorption properties in the blue-UV light region, with the peak values at the order of 8 × 105 cm-1. Particularly, the Janus Bi2Te2S monolayer was found to exhibit a piezoelectric strain coefficient d11 of up to 20.30 pm V-1, which is higher than that of most of the 2D materials. Our results indicate that Janus Bi2X2Y monolayers could be promising candidates in solar cells, optical absorption, and optoelectronic devices; especially, a Janus Bi2Te2S monolayer can also be an excellent piezoelectric material with great prospects in the fields of mechanical and electrical energy conversion.

H–H Configuration of Modular EV Powertrain System Based on the Dual Three-Phase BLDC Motor and Battery-Supercapacitor Power Supply System

A modular approach to the construction of electric machines, drive systems, power supply systems is a new direction of modern technology development. Especially, the modular approach is promising for electric vehicles due to such positive aspects as increased efficiency, fault tolerance, overall reliability, safety, enhanced control capabilities, etc. In this work, the modular approach is comprehensively applied to an EV powertrain system, which includes a dual three-phase (DTP) BLDC motor with two machine modules of an asymmetric configuration, two battery modules and a supercapacitor module (SCM). The proposed H–H configuration of modular EV powertrain system includes four voltage source inverters that combine the power modules with the open ends of the windings (OEW) of the module machine armature, and provide control of their operation. Based on the developed mode system of the OEW machine module operation for EV traction and braking, a general control algorithm for the proposed configuration of the modular EV powertrain system has been developed. It combines the control of the operating modes with the functions of maintaining the required SOC level of the SCM and equalizing the SOCs of the two battery modules. The conducted simulation and experimental studies confirmed the workability and effectiveness of the proposed solutions.

A novel e‐bike energy management for improvement of the rider metabolism

AbstractIn this study, a switch controller manages the power‐sharing between the battery and human mode to improve the rider's metabolism and manage the battery SOC. The main idea is to optimize this power source switching element for changing the status to reach a trade‐off between lack of tiredness and keeping the SOC high. Calorie burning is closely related to the rider's physical characteristics. In this paper, these parameters are investigated to calculate calorie burning. When the electric‐powered mode is activated, the SOC level comes down. When the human‐powered mode is activated, the human power source provides energy. The model converts the bicycle speed into the rider's heart rate and then changes it into burned calories based on some equations. These equations are obtained by poly fitting after experiments. This optimization causes 33.5% and 50% burning calorie reduction in Cleaveland and Portuguese driving cycles. Also, in the Portuguese driving cycle, the battery usage percentage decreases 39.56% from to 20.54% after optimization; therefore, the burning calorie decreases 265.84 Kcal to 176.83 Kcal.

GLP-1 receptor agonist-associated tumor adverse events: A real-world study from 2004 to 2021 based on FAERS.

Background: GLP-1 receptor agonists (GLP-1RA) have demonstrated cardiovascular benefits, but the relationship between GLP-1RA and tumors is controversial. Recently, clinical trials reported higher rates of malignancy with semaglutide than control group. As real-world evidence of GLP-1RA-associated tumor risk is very limited, we explored the association of GLP-1RA and all types of neoplasms by mining the FDA Adverse Event Reporting System (FAERS) database. Methods: The FAERS data from the first quarter (Q1) of 2004 to the second quarter (Q2) of 2020 in the AERSMine were extracted to conduct disproportionality analysis, which was used by the proportional reporting ratio (PRR) to assess the relationship between GLP-1RA and all types of neoplasms. Then, the details of disproportionate GLP-1RA-associated tumor cases from Q1 2004 to Q2 2021 in the FAERS Public Dashboard were collected to analyze demographic characteristics. Results: A total of 8718 GLP-1RA-associated tumors were reported. Excluding cases with pre-existing tumors, other glucose-lowering drugs, and other GLP-1RA-related adverse events, diabetes cases with GLP-1RA as the main suspected drug were selected. GLP-1RA did not cause a disproportionate increase in all tumor cases (PRR 0.83) at the SOC level, and there was also no increase in most types of tumors associated with GLP-1RA at the HLGT/HLT levels. Significant signals were detected between GLP-1RA and certain tumors, including thyroid cancers [medullary thyroid cancer (PRR 27.43) and papillary thyroid cancer (PRR 8.68)], pancreatic neoplasms malignant (PRR 9.86), and islet cell neoplasms and APUDoma NEC (PRR 2.86). The combination of GLP-1RA with dipeptidyl-peptidase IV inhibitors (DPP4i) perhaps caused the increased reporting rate in some tumors. Conclusion: Our study provided new real-world evidence for oncology safety information of GLP-1RA. Given the wide use of GLP-1RA, clinicians should be well informed about important potential adverse events. Our pharmacovigilance analysis also prompted clinicians to raise concerns about potential tumor-related adverse effects when combining GLP-1RA with DPP4i.

Specially-Designed Out-of-Order Processor Architecture for Microcontrollers

In very large-scale integration circuit (VLSI) systems, microcontrollers are often implanted to manage the whole system to complete the given computing tasks. They play an essential part as regulators, which should allocate resources steadily and issue instructions promptly to drive functional units. However, most of the recent research focuses on the operation at the software level or the scheduling at the SoC level, ignoring the impact of the microarchitecture and the features of controlled sub-modules. This paper analyzes the requirements of microcontrollers in the VLSI system with various constraints and conditions that should be considered in the hardware implementation of such microarchitecture. Furthermore, this paper takes an open-source design using RISC-V ISA as the prototype to implement hardware microarchitecture. This design integrates the techniques of out-of-order processing, which are usually used on superscalar processors. As a result, the design quadruples the number of pipelined instructions, greatly alleviating the stalling of the instruction stream with a maximum extra look up table utilization of 18.37% in FPGA implementation.

Novel Fuller Earth, Rock Phosphate, and Biochar for Phytomanagement of Toxic Metals in Polluted Soils

The present study was aimed to assess the efficacy of individual and combined effects of novel fuller earth, rock phosphate, and biochar (grapefruit peel) at 1% dosage on maize plant growth, soil chemical properties anduptake of toxic metals (TMs), such as Cu, Zn, Fe, and Cd, by maize plant sown in Korangi (district of Karachi, Pakistan) heavily polluted and Korangi less polluted (K-HP and K-LP) soils. The obtained results indicate that the dry biomass of maize crop increased by 14.13% with combined (FE1% + GBC1%) on K-HP soil and 18.24% with combined (FE 1% + GBC 1%) effects on K-LP soil. The maximum immobilization of Cu, Zn, Fe, and Cd was observed by 36% with GBC1%, 11.90% with FE1%, 98.97% with combined RP1% + GBC1%, 51.9% with FE1% + GBC1% for K-HP, 11.90% with FE1%, 28.6% with FE1%, 22.22% with RP1% + GBC1%, and 57.05% with FE 1% + GBC 1% for K-LP soil. After the addition of proposed substances, modification of soil OM, SOC, TOC, and pH level appeared this lead to the changes in the phyto-availability of Cu, Zn, Fe, and Cd in maize plant. It was concluded that the application of individual and combined effects of novel fuller earth, rock phosphate, and biochar (grapefruit peel) have potential to stabilize pollutants from multi-metal polluted soils for safe crop production.

Evaluating and Analyzing the Degradation of a Battery Energy Storage System Based on Frequency Regulation Strategies

The capacity aging of lithium-ion energy storage systems is inevitable under long-term use. It has been found in the literature that the aging performance is closely related to battery usage and the current aging state. It follows that different frequency regulation services, C-rates, and maintaining levels of SOC during operation will produce different battery aging rates. In the simulations, the researchers used real frequency data to generate SOC curves based on the Taiwan frequency regulation services under different C-rates and different battery SOC target levels. Then, the aging formula of lithium iron batteries (LiFePO4 battery, LFP battery) and the proposed improved rainflow counting algorithm were used. The capacity aging situation and economy under different usage scenarios were analyzed. The simulation results showed that using a high C-rate and a low SOC level had a higher net profit, and the income of dReg was more than that of sReg. The SOC of BESS has an important impact on the life cycle. Keeping the SOC at a lower level will help prolong the life cycle and increase the net income. In dReg0.5, maintaining the SOC at 30% would yield 8.5% more lifetimes than 50%, 20.6% more lifetimes than 70%.

Mitigating thermal runaway propagation of NCM 811 prismatic batteries via hollow glass microspheres plates

The propagation of thermal runaway in Lithium-ion battery modules can escalate fire hazards and damage in energy storage systems. More effective strategies are needed to ensure the safe application of high-energy lithium-ion batteries and alleviate the thermal runaway propagation. This work explores the use of ultra-light plates based on hollow glass microspheres (HGM) as firewalls in the large-format battery module. A systematic experimental study is conducted using the prismatic battery with LiNi0.8Co0.1Mn0.1O2 (NCM 811) cathode and HGM firewalls with different thicknesses. Performance tests suggest that the composite plate with 60 wt% HGM, 25 wt% curing agent, and 15 wt% flame retardant is most effective in mitigating thermal runaway propagation. Without firewalls, the thermal runaway propagation rate increases from 0.43 cell/min to 0.85 cell/min as the SOC level increases from 25% to 100%. Inserting HGM plates can effectively slow down thermal runaway propagation, where the 3-mm HGM plates can successfully block the thermal runaway. A simplified heat transfer model is also proposed to explain the performance of the firewall in inhibiting thermal runaway and help to optimize the safety design for battery modules. This work provides important insights into the thermal runaway risks and safety measures of large battery systems.

Hierarchical energy management system with multiple operation modes for hybrid DC microgrid

This paper presents a developed energy management system (EMS) with a hierarchical three-level distributed control approach proposed for a photovoltaic/wind turbine/diesel generator with energy storage in an islanded hybrid DC microgrid (MG). In the hierarchical three-level control structure, the power to be transferred by the distributed energy sources (DER) is provided by controlling the converters in the primary control layer. The secondary control layer is used to achieve DC bus voltage restoration and increase current-sharing accuracy simultaneously. In the tertiary control layer, it is aimed to minimize the production cost by performing optimum load-sharing. For the operation of this control structure, a strategy is proposed to optimally manage the energy demand of the hybrid system autonomously under variable load conditions. The EMS with three different operating modes (Mode-I, Mode-II, Mode-III) is proposed to share power between DC MG sources optimally. In Mode-I, renewable energy sources (RES) are enabled to operate with MPPT operation. Energy consumption minimization strategy (ECMS)-based linear programming (LP), genetic algorithm (GA) and pattern search (PS) algorithms are used to minimize the fuel consumption and carbon emissions of the diesel generator (DG) in Mode-II operating Mode. In Mode-III operating mode, DG is not needed, and the power flow between DERs is optimized by using the fuzzy logic controller (FLC) and state machine control strategy (SMCS). The amount of fuel consumed, the cost of fuel consumption and ESS's SOC level are used as the EMS's performance criteria for the MG. The minimum fuel consumption of the DG is calculated as 2.328 L for the operation of LP-based ECMS, and the fuel cost, in this case, is found to be $3.26. Considering the charging of the ESS, the highest SOC level is achieved with 64.87% for the PS-based ECMS-SMCS combination. By considering fuel minimization and SOC level together, it can be seen that the best result is achieved with the LP-based ECMS-SMCS combination.

Wind-Hess System with a Fuzzy base Control Method

The guideline objective of this article is a FUZZY situate Wind-Hess structure control technique to smother wind control change while contemplating the working area of HESS. This article has suggested a fleecy situate breeze HESS network control technique to smother wind control instability while considering the working states (SoC level) of HESS. The key motivation behind the controller is to dole out wind fluctuations with unmistakable repeat gatherings to the super capacitor and the battery by dynamically changing the time steady of primary and discretionary channel channels. The suitability of the suggested technique has been appeared for a watt power network. A feathery situate breeze HESS structure controller is suggested to smother the breeze control instabilities. The suggested controller abuses the complimentary traits of the super capacitor and battery with the super capacitor and battery responsible for high and focus repeat portions of wind changes, independently. In this endeavor PV structure is related with battery for better performance. The capability of the suggested arrangement in the article for wind.

Coordinated Control of Independent Microgrid Based on SOC Deviation Rate

System failure due to high failure rate of independent microgrid energy management system (EMS) in high altitude and cold area, considering the difference in charge state (SOC) between multiple energy storage devices in the system, a power coordinated control strategy based on the SOC deviation rate of energy storage devices is proposed, adjust the output power of the energy storage converter according to the difference in SOC of each energy storage device, reduce the difference in SOC of each energy storage device, after the system EMS fails, the operation status of the energy storage equipment is consistent to ensure the normal operation of the system. The RT-LAB simulation platform is used to establish a simulation model and design a digital control system. The control system can quickly carry out power coordination control according to the SOC state of energy storage devices, so it makes the devices output power differently according to the SOC level, reduces the SOC difference of energy storage devices, makes the devices SOC reach the same, and verifies the feasibility and effectiveness of the coordination control strategy.

Modelling And Simulation Of Pv-Bes Based Microgrid System Operating In Standalone Mode

This work presents, a novel PV-Battery Energy Storage based microgrid system operating in standalone mode. The output of Solar PV changes with varying atmospheric condition. A boost converter is utilized as a DC-DC converter which extracts the maximum power coming out from the solar PV array, with the use of P&O algorithm. Battery Energy Storage System (BESS) is introduced to supply load uninterruptedly. In this project, lead acid battery is used. The energy management is done by the battery control mechanism. Battery and load are connected in parallel with the dc-dc boost converter. Based on the power generation in PV, battery gets charged and discharged. There are two cases considered in this project. In first case, both the load and battery is supplied with generated PV power. In second case, load is supplied with the help of both battery and the Solar PV. The proposed system is modeled and simulated in MATLAB. Parameters like battery current and voltage (Vbat,Ibat),load current and voltage (Vdc,Iout), SOC level of battery are observed and analyzed.

Relieving Grid by Adding PV and BESS for Economical Charging of EV in the Charging Station

Being fueled by electric power, electric vehicles (EVs) are the sustainable alternatives to the conventional vehicles: EVs are likely to alleviate the environmental pollution brought out by excessive use of fossil fuels. To realize electric locomotion, there should be efficient charging facility in our electrical infrastructure to charge the batteries of the EVs. This work proposes an effective topology that focuses to reduce the stress on the grid due to overlapping of EV load profile with the normal Grid-electricity load profile in technically as well as financially feasible way. The EV’s owner can charge his/her vehicle up to desired SOC level from the charging station with sources: PV, BESS and Grid. Here, BESS is a massive energy storage system that can store energy from the grid as well as from the PV system which supplies power to the load during day-time. BESS supplies the load during the peak of the system and helps the grid relieve as well as reduce the Grid-electricity bills during peak hours. Regulation of EV load sharing and prevention of mismatch between circulating currents supplied by power sources is implemented using fixed droop method. The trend of power demand of EVs throughout a day in a charging station is assumed in accordance with the other related works. The economic feasibility of the proposed system is verified in terms of the payback period of the investment made on the PV and BESS. The simulations are successfully implemented to validate the effectiveness of the system and to demonstrate the load management.

Janus Bi2XYZ monolayers for light harvesting and energy conversion from first-principles calculations

Abstract In this work, two-dimensional (2D) Janus Bi2XYZ (X≠Y≠Z, X/Y/Z = S, Se, Te) are predicted to be stable by means of the first-principles calculations. It is of interest that inversion asymmetry induced out-of-plane electric field causes the indirect–direct band gap crossover, band gaps for Bi2SeSTe, Bi2SSeTe and Bi2STeSe are approximately 0.7 eV (at HSE + SOC level of theory). For these Janus structures, carrier mobility reaches up to 3282.05 cm2 V−1 s−1, highly desirable for electronics, light harvesting and energy conversion. Janus Bi2XYZ show strong light–matter interactions, with the optical absorption covering almost the entire incident solar spectrum, thus ensuring efficient utilization of solar energy. For Janus Bi2XYZ, the piezoelectric coefficient d 11 can be as high as 15.01 pm/V due to the inversion symmetry breaking, higher than most of the reported Janus structures. And there is a linear relationship between the piezoelectric coefficient d 11 and the potential energy difference Δ φ between two outmost atomic layers. Our work thus demonstrates that 2D Janus Bi2XYZ hold great promise in applications in such as electronics, light harvesting and energy conversion.

A meta-analysis of serum osteocalcin level in postmenopausal osteoporotic women compared to controls

BackgroundCirculatory osteocalcin (OC) has been widely used as a biomarker to indicate bone turnover status in postmenopausal osteoporosis (PMO). However, the change of serum OC (sOC) level in PMO cases compared to postmenopausal controls remains controversial.MethodsWe searched the online database of PubMed and Cochrane Library. A meta-analysis of case-control studies was performed to compare the pooled sOC level between PMO patients and postmenopausal controls. Subgroup analysis according to potential confounding factors (different OC molecules and regions of the study population) was also performed.ResultsTen case-control studies with 1577 postmenopausal women were included in this meta analysis. We found no significant difference in the pooled sOC level [mean difference (MD) = 1.84, 95% confidence interval (CI): (− 1.49, 5.16), p = 0.28] between PMO patients and controls. Subgroup analysis also revealed no significant difference in intact OC [MD = 1.76, 95%CI: (− 1.71, 5.23), p = 0.32] or N-terminal mid-fragment of the OC molecule [MD = 0.67, 95%(− 5.83, 7.18), p = 0.84] between groups. For different regions, no significant difference in sOC was found in Asian population between cases and controls [MD = -0.06, 95%(− 6.02, 5.89), p = 0.98], while the pooled sOC level was significantly higher in European PMO cases than controls [MD = 3.15, 95%(0.90, 5.39), p = 0.006].ConclusionsOur analysis revealed no significant difference in sOC level between PMO cases and controls according to all the current eligible studies. OC molecules are quite heterogeneous in the circulation and can be influenced by glucose metabolism. Therefore, sOC is currently not a good indicator for the high bone turnover status in PMO. More trials with standardized methodologies for the evaluation of circulatory OC are awaited to update our current findings.