Clinical efficacy and safety of kyphoplasty for the treatment of osteoporotic vertebral compression fractures at different surgical timings based on the theory of“dynamic-static integration”

Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.

Thoracic spinal cord injury and paraplegia caused by intradural cement leakage after percutaneous kyphoplasty: A case report

BACKGROUND Percutaneous kyphoplasty(PKP)is a pivotal intervention for osteoporotic fractures,pathological vertebral compression fractures,and vertebral bone tumors.Despite its efficacy,the procedure presents challenges,notably complications arising from intradural cement leakage.Timely and accurate diagnosis,coupled with emergent intervention is imperative to improve patient prognosis.This case report illuminates the intricacies and potential complications associated with PKP,emphasizing the critical need for vigilant monitoring,prompt diagnosis,and immediate intervention to mitigate adverse outcomes.CASE SUMMARY A 58-year-old male patient,experiencing a T7 osteoporosis-related pathological compression fracture,underwent PKP at a local hospital.Two weeks postprocedure,the patient developed paraplegic and dysuric symptoms,necessitating emergency decompression surgery.Gradual improvement was achieved,marked by the restoration of muscle strength,sensation,and mobility.CONCLUSION PKP Intradural cement leakage following PKP is unusual and potentially fatal.Prompt imaging examinations,urgent evaluation,and the decompression surgery are essential,which help alleviate symptoms associated with spinal damage,markedly improving the overall prognosis.

Effect of Fine Steel Slag Powder on the Early Hydration Process of Portland Cement

Hydration heat evolution, non-evaporative water, setting time and SEM tests were peorormed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism. The results show that the effect of fine steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases, fineness, etc. Fine steel slag powder retards the hydration of portland cement at early age. The major reason for this phenomenon is the relative high content of MgO , MnO2, P2O5 in steel slag, and MgO solid solved in C3 S contained in steel slag.

Spatiotemporal evolution of thermo-hydro-mechanical-chemical processes in cemented paste backfill under interfacial loading

Cemented paste backfill(CPB)and rock interface interaction causes the formation of an interfacial loading and affects the thermal,hydraulic,mechanical,and chemical processes in bulk CPB and thus its in-situ behavior.In this study,a new meter-sized column model is developed to systematically investigate the multiphysics processes in CPB under interfacial loading.The obtained results discover that for the mechanical process,the interfacial loading leads to a reduced settlement and a weakened stress level in CPB.For the hydraulic process,lower matric suction and smaller moisture content coexist in CPB under interfacial loading.For the thermal process,the interfacial loading weakens the porosity-dependent thermal conduction and causes retardation in temperature variation relative to the ambient temperature.For the chemical process,weakened cement hydration with smaller electrical conductivity was observed in CPB under interfacial loading.Therefore,the obtained results reveal the linkage between the interfacial loading and multiphysics processes in CPB and thus contribute to an in-depth understanding of the multiphysics behavior of CPB in underground mines.

Effect of Nano-TiO_2 Addition on the Hydration and Hardening Process of Sulphoaluminate Cement

The influences of nano-TiO2 on the setting time, hydration process, hydration products and morphology of sulphoaluminate cement were studied by Vicar apparatus, isothermal calorimetry, X-ray diffraction （XRD）, thermal analysis and scanning electron microscopy （SEM）. The experimental results show that the incorporation of nano-TiO2 can obviously promote the setting and hardening process of sulphoaluminate cement, and shorten the interval between the initial and final setting time, the hydration induction period of sulphoaluminate cement is significantly shortened and the acceleration period begins immediately, but the hydration exothermic rate at hydration stationary phase is not obviously impacted. The nano-TiO2 additives have influence on the formation rate and degree of crystallinity, but do not affect the type of hydration process. The structure of hydration products is compact at middle age, but their content and microstructure do not change

EFFECT OF BURNING METHOD ON THE FORMING PROCESSES OF PORTLAND CEMENT CLINKER

The forming temperature of Clinker melt underdifferent burning conditions has been studied by appearance examination and thermal shrinker determination, and the viscosity of melt has been discussed by studying the coordination number of Al^(3+) and Fe^(3+) in cement clinker burned by different method with x^- ray fluorescence analysis and Moss- bauer spectroscopy. The results show that the clin- ker melt under rapid burning may come into exis- tence at lower temperature and It's viscosity is lower. So the forming processes of clinker may be different at rapid burning from ordinary burning. They are probably an important factor to promote the formation of clinker burned at lower temperature with rapid burning method.

Energy and Cost Analysis of Cement Production Using the Wet and Dry Processes in Nigeria

The study evaluates the energy consumption of both wet and dry processes cement manufacturing plant in Nigeria. Enrgy consumption data collected for the period 2003 to 2011 were used to estimate the energy consumption of the crushing, milling, agitation, burning, grinding and bagging operations. The total energy evaluation was based on the three primary energy sources which include electrical, combustion and human. The total estimated energy intensities were 6545 MJ/ton and 4197 MJ/ton for wet and dry processes respectively. The percentage consumption of energy in each operation is 93.68 and 90.34% (burning), 2.11 and 4.33% (milling), 0.43 and 0.67% (crushing), 1.39 and 0% (agitation), 2.12 and 3.90% (grinding), and 0.27 and 0.75% (bagging) of the total energy inputs for the wet and dry processes respectively. Furthermore, the average total energy cost of production showed that wet process is approximately 40% more cost intensive in cement production than the dry process while at the same time it is cost effective to run production on energy through gas powered plant than the national grid.

Influence of Pressure on the Annealing Process of β-Ca_2SiO_4(C_2S) in Portland Cement

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-speciality grout. Dicalcium silicate （Ca2SiO4） is the primary constituent of a number of different types of cement. The β-Ca2SiO4 phase is metastable at room temperature and will transform into β-Ca2SiO4 at 663K. In this work, Portland cement is annealed at a temperature of 950K under pressures in the range of 0-5.5 CPa. The high pressure experiments are carried out in an apparatus with six anvil tops. The effect of high pressure on the obtaining nano-size β-Ca2SiO4 （C2S） process is investigated by x-ray diffraction and transmission electron microscopy. Experimental results show that the grain size of the C2S decreases with the increase of pressure. The volume fraction of the C2S phase increases with the pressure as the pressure is below 3 CPa, and then decreases （P 〉 3 GPa）. The nano-effect is very important to the stabilization of β-Ca2SiO4. The mechanism for the effects of the high pressure on the annealing process of the Portland cement is also discussed.

Elimination of ESD Events and Optimizing Waterjet Deflash Process for Reduction of Leakage Current Failures on QFN-mr Leadframe Devices

This technical paper presents the resolution of high leakage current failures on QFN-mr （Quad-Flat No-leads Multi-Row） LF （leadframe） devices by optimizing the waterjet deflash process and eliminating the ESD （electrostatic discharge） events. ESD damage to units can cause permanent or latent product failures which results in low final test yield, and worse, possible external customer complaints. The use of CO2 （carbon dioxide） bubbler was able to reduce the DI （deionized） water’s equivalent resistivity from 17 M？ to 0.30 M？, minimizing the tribocharging effect produced during the waterjet deflash process. Moreover, ESD events were eliminated by grounding the floating assembly equipment parts and installing appropriate ESD controls. It is of high importance to reduce or eliminate the leakage current failures to ensure the product quality, especially as the market becomes more demanding. After the optimization and implementation of the corrective and improvement actions, high leakage current occurrence was significantly reduced from baseline of 5,784 ppm to 20 ppm.

Microstructure and high temperature oxidation resistance of Si-Y co-deposition coatings prepared on TiAl alloy by pack cementation process

In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.

Research on Volume Identification with the Method of Discharging at the Velocity of Sound

The method of volume identification in pneumatics was studied through theoretical analysis and experimental investigation. Regarding discharging from a container as a thermodynamic process with invariable index the dependence of the container’s volume on the pressure in the container and the index, during discharging at the velocity of sound, is deduced. Then through a lot of experiments, the value of index n of the process is found with a given precision and a specified volume range. Furthermore, the feasibility and practicability of this method are verified by experiments.

Rheological properties of a multiscale granular system during mixing of cemented paste backfill:A review

The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requirements.As a multiscale granular system,homogenization is one of the challenges in the paste-mixing process.Due to the high shearing,high concentration,and multiscale characteristics,paste exhibits complex rheological properties in the mixing process.An overview of the mesomechanics and structural evolution is presented in this review.The effects of various influencing factors on the paste's rheological properties were investigated,and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels.The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste.Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags.

Multi-site anchoring of single-molecule for efficient and stable perovskite solar cells with lead shielding

The emergence of perovskite solar cells(PSCs) has greatly promoted the progress of photovoltaic technologies.The rapid development of PSCs has been driven by the advances in optimizing perovskite films and their adjacent interfaces.However,the polycrystalline perovskite layers in most highly efficient PSCs still contain various defects that greatly limit photovoltaic performance and stability of the devices.Herein,we introduce a multifunctional additive ethylene diamine tetra methylene phosphonic sodium(EDTMPS) with multiple anchor points into the precursor of perovskite to improve the efficiency and stability of PSCs and provide in-situ protection of lead leakage.The addition of EDTMPS acts as a crystal growth controller and passivation agent for perovskite films,thereby slowing down the crystallization rate of the film and obtaining high-quality perovskite films.Our study also provides an insight into how the modifier modulate the interfacial energy level arrangement as well as affect transfer of charge carriers and their recombination under photoinduced excitation.As a result,the power conversion efficiency(PCE) of single subcell with a working area of 0.255 cm^(2) increases significantly from 20.03% to 23.37%.Moreover,we obtained a PCE of 19.16% for the 25 cm^(2) module.Importantly,the unencapsulated EDTMP-modified PSCs exhibit better operational and thermal stability,as well as in-situ absorption of leaked lead ions.

Delayed complications of intradural cement leakage after percutaneous vertebroplasty:A case report

BACKGROUND Intradural cement leakage following percutaneous vertebroplasty is a rare but acute and devastating complication that usually requires emergent treatment.Here,we report a delayed complication of intradural leakage after percutaneous vertebroplasty.CASE SUMMARY A 71-year-old female patient with an L1 osteoporotic compression fracture underwent percutaneous vertebroplasty in 2014.She was referred to our hospital 5 years later due to complaints of progressive weakness and numbness in both legs combined with urinary incontinence and constipation.Initially,she was suspected to have a spinal meningioma at the level of L1 according to imaging examinations.Postoperative pathological tests confirmed that cement had leaked into the dura during the first percutaneous vertebroplasty.CONCLUSION Guideline adherence is essential to prevent cement from leaking into the spinal canal or even the dura.Once leakage occurs,urgent evaluation and decompression surgery are necessary to prevent further neurological damage.

Effects of Municipal Sewage Sludge on Fixation of Cr,Ni,Cu,and Zn during Co-processing of Heavy Metal-containing Waste in Cement Kilns

Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixation ratio of Cr, Ni, Cu, and Zn in the produced clinker by 5% to 25%. And Cr, Cu, and Zn were mainly incorporated into clinkers as metal silicates, Ni was mainly solubilized in Mg O to form magnesium nickel oxides, and the transition phases were mainly metal aluminum oxides as indicated by X-ray diffraction. The reduction of fixation ratios was likely attributed to the presence of impure elements, such as sodium and phosphorus in MSS. In addition, high concentrations（eg, 1.7 wt%） of chlorine in MSS led to metal chloride formation that could vaporize Cu, Cr, Ni, and Zn. To summarize, introducing MSS would decrease the fixation ratios of heavy metals due to the presence of impure elements, such as sodium and phosphorus and chlorine.

An <i>in Vitro</i>Study of Microleakage Comparing Total-Etch with Bonding Resin and Self-Etch Adhesive Luting Cements for All-Ceramic Crowns

Aim: The aim of the study was to assess the dye leakage present following cementation of all-ceramic crowns with 7 currently used cements to compare total-etch (TE) with dentine bonding agent (DBA) and self-etch (SE) systems. Methods: Forty-two Authentic? crowns were fabricated and cemented onto extracted human teeth using 7 currently available cements (2 two-stage adhesives (TE + DBA): Panavia 21 Kuraray;Paracore, Coltene Whaledent and 5 all-in-one adhesives (SE): MaxCem Kerr;Panavia F2.0 Kuraray;RelyX Unicem 3MEspe;seT SDI). Following storage in water and thermal cycling, the teeth were exposed to dye, sectioned and examined under confocal microscopy. Leakage was determined by two blinded examiners and scoring was carried out on a scale of 0 - 8 per tooth (0 = no leakage, 8 complete leakage across the section). One overall reading was obtained per tooth with 6 teeth per material. Results: The results showed a wide range of scores between the different cements. Only a few specimens which used TE + DBA showed slight marginal leakage: Paracore (mean score 0 ± 0) and Panavia 21 (0.3 ± 0.5). The majority of specimens using SE showed leakage: RelyX Unicem (0.8 ± 0.8), SmartCem (1.7 ± 2.1), MaxCem (3.2 ± 1.7), Panavia F2.0 (4.5 ± 2.4) then seT (5.2 ± 2.5). Statistical analysis was carried out showing that Paracore and Panavia 21 were significantly less prone to leakage than MaxCem, (P = 0.002) and seT (P < 0.001). Conclusion: In conclusion, the choice of luting cement is important in reducing dye leakage. This study strongly favours the use of a TE with separate adhesive system placed prior to the composite luting resin.

Humanoid Based Intelligence Control Strategy of Plastic Cement Die Press Work-Piece Forming Process for Polymer Plastics

The plastic cement belongs to a sort of polymer material, the chemical composition is very complex, and the plastic cement work-piece is generally manufactured by die press forming. Aimed at being difficult to control in parameters of forming process, the paper explored the humanoid based intelligence control strategy. In the paper, it made the anatomy in control puzzle resulted in uncertainty such as chemical component of plastic cement etc., summarized up the characteristic of cybernetics in forming process, researched on the humanoid based intelligence control strategy, and constructed the control algorithm of forming process in plastic cement work-piece. Taking the process experiment of temperature and pressure control as an example, it validated the good dynamic and static control quality through simulation of control algorithm constructed in this paper. The experimental results show that the control algorithm explored in this paper is reasonably available.

Experimental Investigation of the Impact of Compression on the Petro-Physical and Micromechanical Properties of Wellbore Cement Containing Salt

In this study, we investigated the effect of compression on the micromechanical and the petro- physical properties of salted wellbore cement systems. The experiments were conducted using a customized bench scale model, which utilized an expandable tubulars simulating the compression of a previously cemented casing under field-like conditions. The “mini-wellbore model” sample consisted of a pipe inside pipe assembly with a cemented annulus. The cement samples were cured in a water bath for 28 days prior to the compression experiments to allow adequate hydration. The impact of compression on the cement’s petro-physical and mechanical properties was quantified by measuring the porosity, permeability and hardness of salt cement cores drilled parallel to the orientation of the pipe from the compacted cement sheath. Permeability (Core-flood) experiments were conducted at 21℃, 10,342 kPa confining pressure for a period of 120 minutes. During the core-flood experiments, conducted using Pulse-decay method, deionized water was flowed through cement cores to determine the permeability of the cores. The results obtained from these experiments confirmed that the compression of the cement positively impacted the cements ability to provide long term zonal isolation, shown by the effective reduction in porosity and permeability. Furthermore, the results confirm reduction in the detrimental effect of salt on the strength and stiffness in post-compression cement.

Removal of cadmium from aqueous solutions using red mud granulated with cement

A novel adsorbent was prepared from granular red mud mixed with cement and its potential to be a suitable adsorbent for the removal of cadmium ions from aqueous solutions was evaluated. The wet red mud was directly mixed up with cement at different mass fractions of 2%-8% and their properties were investigated. Based on the textural characteristics and strength, the granular red mud with 2% addition of cement maintaining for 6 d is identified to have better properties. The batch adsorption experiments for adsorption of Cd2+ ions from solution were performed at 30, 40 and 50 °C at different initial concentrations under the condition of constant pH of 6.5. The equilibrium adsorption was found to increase with the increase of temperature during the adsorption process. Langmuir adsorption isotherm model was found to match the experimental adsorption isotherm better. The kinetics of adsorption was modeled using a pseudo second order kinetic model and the model parameters were estimated.