Kinematic characteristics of lumbar spinous processes during axial rotation in patients with lumbar degenerative disc disease lateral lumbar interbody fusion and intervention

Abstract Background Data about minimally invasive surgery for the treatment of patients with degenerative disc disease (DDD) has been reported. However, no quantitative knowledge about the biomechanical characteristics of the spinous processes in patients with DDD after operation was reported in the literature. Methods Fourteen adult patients with DDD at the L3-4 level were recruited and scanned using computed tomography (CT) to construct three-dimensional (3D) anatomical vertebral models of L2-5. These patients were asked to maintain four positions to acquire 6DOF data about the area of the spine being investigated (L2-5). Fluoroscopy was used to capture spinal motion. 6DOF data from the fluoroscopic images of the four positions was compared to evaluate the kinematics before operation and 6 months after direct lateral interbody fixation (DLIF). Results Altered kinematics were found mainly in rotation. For the images captured while patients were in the supine position, no significant differences were detected in different functional positions before and after operation. At other positions, the most kinematic involved level was the L3-4 level, which was followed by the L4-5 level. The range of flexion-extension motion at all levels decreased after operation (by an average of 1° to 7°) while different trends were found in left-right bending/rotation. Overall, after surgical treatment, functional activities were partially restored. Conclusions Overall the lumbar spinous processes (LSP) at each level responded differently, regarding rotation, before and after DLIF. This data provides new insights for the evaluation of function before and after surgical treatment in patients with LSP disease

A New Adaptive GCC Method and Its Application to Slug Flow Velocity Measurement in Small Channels

In this work, an adaptive generalized cross-correlation (AGCC) method is proposed that focuses on the problem of the conventional cross-correlation method not effectively realizing the time delay estimation of signals with strong periodicity. With the proposed method, the periodicity of signals is judged and the center frequencies of the strongly periodical components are determined through the spectral analysis of the input signals. Band-stop filters that are used to suppress the strongly periodical components are designed and the mutual power spectral density of the input signals that is processed by the band-stop filters is calculated. Then, the cross-correlation function that is processed is the inverse Fourier transform of the mutual power spectral density. Finally, the time delay is estimated by seeking the peak position of the processed cross-correlation function. Simulation experiments and practical velocity measurement experiments were carried out to verify the effectiveness of the proposed AGCC method. The experimental results showed that the new AGCC method could effectively realize the time delay estimation of signals with strong periodicity. In the simulation experiments, the new method could realize the effective time delay estimation of signals with strong periodicity when the energy ratio of the strongly periodical component to the aperiodic component was under 150. Meanwhile, the cross-correlation method and other generalized cross-correlation methods fail in time delay estimation when the energy ratio is higher than 30. In the practical experiments, the velocity measurement of slug flow with strong periodicity was implemented in small channels with inner diameters of 2.0 mm, 2.5 mm and 3.0 mm. With the proposed method, the relative errors of the velocity measurement were less than 4.50%

Multiscale analysis of fine slag from pulverized coal gasification in entrained-flow bed

Abstract Fine slag (FS) is an unavoidable by-product of coal gasification. FS, which is a simple heap of solid waste left in the open air, easily causes environmental pollution and has a low resource utilization rate, thereby restricting the development of energy-saving coal gasification technologies. The multiscale analysis of FS performed in this study indicates typical grain size distribution, composition, crystalline structure, and chemical bonding characteristics. The FS primarily contained inorganic and carbon components (dry bases) and exhibited a "three-peak distribution" of the grain size and regular spheroidal as well as irregular shapes. The irregular particles were mainly adsorbed onto the structure and had a dense distribution and multiple pores and folds. The carbon constituents were primarily amorphous in structure, with a certain degree of order and active sites. C 1s XPS spectrum indicated the presence of C–C and C–H bonds and numerous aromatic structures. The inorganic components, constituting 90% of the total sample, were primarily silicon, aluminum, iron, and calcium. The inorganic components contained Si–O-Si, Si–O–Al, Si–O, SO4 2−, and Fe–O bonds. Fe 2p XPS spectrum could be deconvoluted into Fe 2p 1/2 and Fe 2p 3/2 peaks and satellite peaks, while Fe existed mainly in the form of Fe(III). The findings of this study will be beneficial in resource utilization and formation mechanism of fine slag in future

Global Burden of Ischemic Heart Disease from 2022 to 2050: Projections of Incidence, Prevalence, Deaths, and Disability-Adjusted Life Years

Aims: Ischaemic heart disease (IHD) has been a significant public health issue worldwide. This study aims to predict the global burden of IHD in a timely and comprehensive manner. Methods and results: Incidence, prevalence, deaths, and disability-adjusted life years (DALYs) for IHD from 1990 to 2021 were derived from the Global Burden of Disease 2021 database, and three models (linear, exponential, and Poisson regression) were used to estimate their trends over time at the global, regional, and national levels by age, sex, and country groups, with the gross domestic product per capita was applied to adjust the model. The model results revealed that the global burden of IHD is expected to increase continuously by 2050. By 2050, global IHD incidence, prevalence, deaths, and DALYs are projected to reach 67.3 million, 510 million, 16 million, and 302 million, respectively, which represents an increase of 116%, 106%, 80%, and 62%, respectively, from 2021. Moreover, the results showed that regions with lower sociodemographic index (SDI) bore a greater burden of IHD than those with higher SDI, with men having a higher burden of IHD than women. People over 70 years old account for a major part of the burden of IHD, and premature death of IHD is also becoming more serious. Conclusion: The global burden of IHD will increase further by 2050, potentially due to population ageing and economic disparities. Hence, it is necessary to strengthen the prevention of IHD and formulate targeted strategies according to different SDI regions and special populations

An antibacterial and absorbable silk-based fixation material with impressive mechanical properties and biocompatibility

Implant-associated infections and non-absorbing materials are two important reasons for a second surgical procedure to remove internal fixation devices after an orthopedic internal fixation surgery. The objective of this study was to produce an antibacterial and absorbable fixation screw by adding gentamicin to silk-based materials. The antibacterial activity was assessed against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in vitro by plate cultivation and scanning electron microscopy (SEM). We also investigated the properties, such as the mechanical features, swelling properties, biocompatibility and degradation, of gentamicin-loaded silk-based screws (GSS) in vitro. The GSS showed significant bactericidal effects against S. aureus and E. coli. The antibacterial activity remained high even after 4 weeks of immersion in protease solution. In addition, the GSS maintained the remarkable mechanical properties and excellent biocompatibility of pure silk-based screws (PSS). Interestingly, after gentamicin incorporation, the degradation rate and water-absorbing capacity increased and decreased, respectively. These GSS provide both impressive material properties and antibacterial activity and have great potential for use in orthopedic implants to reduce the incidence of second surgeries

Rubidium isotopic fractionation during magmatic processes and the composition of the bulk silicate Earth

International audienceRubidium is a moderately volatile element with high incompatibility and fluid mobility. Its stable isotopes have great potential in tracing various geological processes. For example, lunar rocks are isotopically heavier than terrestrial ones, suggesting volatile loss by evaporation during or following the formation of the Moon. However, these studies rely on a poorly constrained estimate for the composition of the Earth's mantle and a poor understanding of high-temperature processes which may act to fractionate stable Rb isotopes. It is therefore important to precisely characterize different rock types that sample the Earth's mantle as well as to evaluate the importance of key isotopic fractionation processes. In order to address these issues, we established a high precision analytical method for Rb isotopic measurements using the Nu Sapphire CC-MC-ICP-MS (collision-cell multi-collector inductively coupled plasma mass spectrometer). In addition, we present a series of Rb isotopic data of volcanic rocks from Hekla volcano (Iceland) and MORB (mid-ocean ridge basalt) samples. We show that our method returns a high Rb sensitivity (∼500 V/μg·g-1 for 85Rb) and a long-term reproducibility of 0.03‰ on δ87Rb (the permil deviation of the 87Rb/85Rb ratio from the SRM 984 standard). This method uses a 2 ng/g Rb solution for analyses, allowing us to consume about 10 times less Rb to achieve similar or better precision than previous studies. Using this method, seven geostandards and one synthetic standard return Rb isotopic data consistent with previous work. Twenty-one Hekla volcanic rocks, spanning compositions from basalt to rhyolite, show limited Rb isotopic variation, with δ87Rb values varying from -0.17‰ to -0.07‰, demonstrating that magmatic evolution has an insignificant effect on Rb isotope ratios. A set of MORB samples (n = 15) from different mid-ocean ridges also span a limited Rb isotopic variation, displaying a range similar to the Hekla rock suite (-0.19 to -0.02‰). Combining our new data together with previously reported OIB data gives an average δ87Rb value of -0.12 ± 0.08‰ (2SD, n = 25), representing the current best estimate of the mantle's isotopic composition. Considering the δ87Rb values of the upper continental crust (-0.14 ± 0.01‰, 2SE, n = 73), as inferred from recent measurements of granites, loess and sediments, and assuming this value represents the whole crust, the revised Rb isotopic composition of the bulk silicate Earth (and by extension the bulk Earth, assuming no Rb partitioned into the core) is -0.13 ± 0.06‰ (2SD)

Self-Assembly Behavior of Thermoresponsive Oligo(ethylene glycol) Methacrylates Random Copolymer

A well-defined random copolymer containing 2-(2-methoxyethoxy) ethyl methacrylate (MEO₂MA, <i>M</i>_n = 188 g/mol) and poly­(ethylene glycol) methyl ether methacrylate (PEGMA, <i>M</i>_n = 2080 g/mol) (poly­(MEO₂MA-<i>co</i>-PEGMA₂₀₈₀)), <i>M</i>_n = 17300 g/mol) was synthesized using the atom transfer radical polymerization (ATRP) process, and its thermoresponsive behaviors in aqueous solution were investigated. In comparison to other temperature-sensitive random copolymers based on oligo­(ethylene glycol) methacrylates, this copolymer exhibited an unusual thermally induced two-stage aggregation process. The copolymer chains associate at the first thermal transition followed by a rearrangement process at the second thermal transition to produce a stable core–shell micellar structure. The morphology of the micelle comprises of a methacrylate core stabilized by the longer ethylene glycol segments (<i>M</i>_n = 2080 g/mol) shell