C4 C5 Research Articles

Application of coniferous bark as sorbent material for per- and polyfluoroalkyl substances – A case study in Sweden

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic contaminants commonly found in drainage water from waste management facilities. Within the European Union, these facilities either treat the water locally or transfer it to wastewater treatment plants to reduce harmful emissions. However, PFAS are a broad class of compounds with varying physicochemical properties, leading to different removal efficiencies for adsorbents. Activated carbon and ion exchange resins are effective but costly, and they can become saturated with other contaminants. Therefore, this study aims to explore inexpensive, abundant alternatives for reducing PFAS concentrations in the environment. In Sweden, bark is a by-product of forestry activities, primarily used as fuel in heat and power plants. This study evaluates the ability of pine and spruce bark to remove PFAS from contaminated drainage water. Initial laboratory experiments employed liquid-to-solid ratios of 10 and 20 to assess the performance of both materials. Results indicated that pine bark exhibited better removal efficiencies, particularly when a layered column with pine bark followed by spruce bark was utilized. The overall removal efficiencies for short-chain PFAS (perfluorinated carbons: PFCA C3–C6 and PFSA C4–C5) and long-chain PFAS (PFCA > C7 and PFSA > C6) were below 20%, except for perfluorooctane sulfonic acid (PFOS), which showed reductions of 40%–80%. The pH of the treated water decreased from 7 to 4 (pine bark) and 5 (spruce bark) after treatment. In a larger-scale trial, a combination of 50% pine bark and 50% spruce bark was tested, achieving similar reductions for PFOS. Although the removal efficiencies were insufficient for exclusive treatment, these materials may be useful in specific applications targeting long-chain PFAS or in conjunction with other treatment methods.

Finite element analysis of a three-dimensional cervical spine model with muscles based on CT scan data

Background The incidence of cervical spondylosis is increasing, gradually affecting people’s normal lives. Establishing a finite element model of the cervical spine is one of the methods for studying cervical spondylosis. MRI (Magnetic Resonance Imaging) still has certain difficulties in transitioning from human imaging to establishing muscle models suitable for finite element analysis. Medical software provides specific morphologies and can generate muscle finite element models. Additionally, there is little research on the static analysis of cervical spine finite element models with solid muscle. Purpose A new method is proposed for establishing a finite element model of the cervical spine based on CT (Computed Tomography) data and medical software, and the model’s effectiveness is validated. Human movement characteristics based on the force distribution in various parts are analyzed and predicted. Methods The muscle model is reconstructed in medical software and a three-dimensional finite element model of the entire cervical spine (C0–C7) is established by combining muscle models with CT vertebral data models. 1.5 Nm of load is applied to the finite element model to simulate the cervical spine movement. Results The finite element model was successfully established, and effectiveness was verified. Stress variations in various parts under six movements were obtained. The effectiveness of the model was basically verified. Conclusion The finite element model of the cervical spine for mechanical analysis can be successfully established by using medical software and CT data. In daily life, the C2–3, C3–4, C4–C5 intervertebral discs, rectus capitis posterior major, longus colli, and obliquus capitis inferior are more prone to injury.

Integrated microbiome and metabolome analysis reveals that new insight into Radix pseudostellariae polysaccharide enhances PRRSV inactivated vaccine.

In this study, we investigated how Radix pseudostellariae polysaccharide (RPP) enhances the immune response of the inactivated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine through interactions with the microbiome and metabolome. We pretreated sows with 10 mg/kg body weight of RPP via drinking water for 7 days prior to intramuscular injection of the PRRSV vaccine. This significantly increased the concentrations of PRRSV GP5 protein antibody, interleukin (IL)-2, IL-4, IL-10, and interferon (IFN)-γ. Oral administration of RPP also significantly improved the abundance of beneficial bacteria in the stool, such as Parabacteroides distasonis, Prevotella_copri, Eubacterium_sp., and Clostridium_sp._CAG:226, and decreased the levels of potentially pathogenic bacteria, such as Paraeggerthella and [Clostridium] innocuum, compared to the vaccine alone. These bacterial changes were confirmed using quantitative real-time polymerase chain reaction (Q-PCR). Moreover, RPP treatment significantly increased the blood concentrations of L-theanine, taurodeoxycholic acid (TDCA), and N-arachidonoyl proline, and decreased the levels of L-glutamine, oclacitinib, lipoxin C4, and leukotriene C5 in sows after immunization (p< 0.05). The concentrations of various blood metabolites were validated using sandwich enzyme-linked immunosorbent assay (ELISA), confirming the accuracy of the metabolomics data. Intriguingly, the integration of microbiome and metabolome analyses highlighted the significance of Prevotella_copri and TDCA. We consequently developed a mouse immunity model using GP5 protein and discovered that oral administration of RPP significantly enhanced the levels of GP5 protein antibodies, IL-2, IL-4, IL-10, and IFN-γ in mouse serum. It also increased the number of CD3+ and CD3+CD4+ cells in the spleen. Additionally, Prevotella_copri was administered into the large intestine via the anus for 7 days prior to the intramuscular injection of the PRRSV GP5 protein. The results demonstrated a significant increase in TDCA and GP5 antibody concentration in the mouse serum, indicating that RPP modulates Prevotella_copri to elevate its metabolite TDCA, thereby enhancing the GP5 antibody level. In conclusion, oral administration of 10 mg/kg RPP optimizes gut flora diversity and blood metabolites, particularly Prevotella_copri and TDCA, thereby improving the immune response to the inactivated PRRSV vaccine.

Complexities of peroxyacetyl nitrate photochemistry and its control strategies in contrasting environments in the Pearl River Delta region

Peroxyacetyl nitrate (PAN) is a hazardous secondary pollutant and a nitrogen reservoir in the troposphere, while comprehensive studies on its spatiotemporal distribution, chemical sources, and control strategies are limited. This study addressed these issues based on 1-year multi-site observations in the Pearl River Delta region, showing a pattern of higher PAN levels in the cold season, particularly in coastal areas. Moreover, in situ modeling indicated a net photochemical PAN formation in the warm season, while PAN was dominated by regional transport in the cold season (i.e., rural and coastal areas), releasing NO2 and PA radicals and promoting ozone (O3) formation. In addition, the feasibility of joint control of PAN and O3 was confirmed by their isopleth diagrams. C7–C9 aromatics and C4–C5 alkenes, largely from vehicle exhaust and solvent usage, were identified as the predominant contributors to PAN formation in this region. Overall, this study deepens our understanding of PAN chemistry and provides valuable insights into its control measures.

Hydroformylation of Lower Olefins and the Use of Oxo Synthesis Products Based on C4–C5 Aldehydes in the Production of Ester Lubricating Oils. Part 2. Rhodium Processes Developped in LLC «RN-RD Center»

Hydroformylation of Lower Olefins and the Use of Oxo Synthesis Products Based on C4–C5 Aldehydes in the Production of Ester Lubricating Oils. Part 2. Rhodium Processes Developped in LLC «RN-RD Center»

Non-traumatic complete cervical spine dislocation with severe fixed kyphosis: successful multidisciplinary approach to a challenging case

BackgroundTo our knowledge, there is no previous report in the literature of non-traumatic neglected complete cervical spine dislocation characterized by anterior spondyloptosis of C4, extreme head drop, and irreducible cervicothoracic kyphosis.Case presentationWe report the case of a 33-year-old Caucasian man with a 17-year history of severe immune polymyositis and regular physiotherapy who presented with severe non-reducible kyphosis of the cervicothoracic junction and progressive tetraparesia for several weeks after a physiotherapy session. Radiographs, computed tomography, and magnetic resonance imaging revealed a complete dislocation at the C4–C5 level, with C4 spondyloptosis, kyphotic angulation, spinal cord compression, and severe myelopathy. Due to recent worsening of neurological symptoms, an invasive treatment strategy was indicated. The patient’s neurological status and spinal deformity greatly complicated the anesthetic and surgical management, which was planned after extensive multidisciplinary discussion and relied on close collaboration between the orthopedic surgeon and the anesthetist. Regarding anesthesia, difficult airway access was expected due to severe cervical angulation, limited mouth opening, and thyromental distance, with high risk of difficult ventilation and intubation. Patient management was further complicated by a theoretical risk of neurogenic shock, motor and sensory deterioration, instability due to position changes during surgery, and postoperative respiratory failure. Regarding surgery, a multistage approach was carefully planned. After a failed attempt at closed reduction, a three-stage surgical procedure was performed to reduce displacement and stabilize the spine, resulting in correct spinal realignment and fixation. Progressive complete neurological recovery was observed.ConclusionThis case illustrates the successful management of a critical situation based on a multidisciplinary collaboration involving radiologists, anesthesiologists, and spine surgeons.

Synergistic enhancement of CO2 hydrogenation to C5+ hydrocarbons using mixed Fe5C2 and Na-Fe3O4 catalysts: Effects of oxide/carbide ratio, proximity, and reduction

CO2 hydrogenation into sustainable chemical feedstocks and fuels is a pivotal focus of energy research. Fe-based catalysts have emerged as promising candidates due to their high efficiency in the CO2 hydrogenation toward C2–C4 olefins and C5+ hydrocarbons. Fe5C2 is known as the active phase of the CO2 hydrogenation. Therefore, it is imperative to discern the roles of active phases in product distribution. Accordingly, in the present study, Fe5C2 is synthesized separately and physically mixed with Na-Fe3O4. The effects of oxide/carbide ratio, the proximity of active phases, and reduction treatment are investigated. The results show that adding carbide to oxide in an appropriate ratio significantly increases CO2 conversion due to the controlled reduction of the oxide phase and enhanced CO2 adsorption. Additionally, a closer distance (mixed-powder pellets) between Na-Fe3O4 and Fe5C2 results in higher selectivity for C2-C4 olefins and C5+ hydrocarbons and less CH4. Furthermore, the graphitized layers of reduced catalyst (R-Na-Fe3O4/Fe5C2 (70/30 wt%)) enhance the selectivity to C2-C4 olefins (40 %) and C5+ hydrocarbons (35 %) at around 40 % CO2 conversion. In contrast, amorphous carbon in the non-reduced catalyst (NR-Na-Fe3O4/Fe5C2 (70/30 wt%)) favors more C2-C4 paraffins and CH4. Therefore, the interplay between the influential factors, i.e., oxide/carbide ratio, spatial distance, and reduction treatment, can result in tailoring an efficient CO2 hydrogenation catalyst toward the formation of valuable hydrocarbons.

Preparation and Properties of Silane Coupling Agent Modified Basalt Flake Polyurethane Anti-Corrosion Coatings

Strong corrosive atmospheric environments of level C4–C5 have a serious safety impact on steel structures and industrial production. The use of anti-corrosion coatings is the most economical and efficient way of all means of anti-corrosion. To further improve the anticorrosion performance of polyurethane anticorrosion coatings, this paper adopts KH-560 silane coupling agent to modify basalt flake and add it as filler into one-component polyurethane resin with wet curing characteristics. Anti-corrosion coatings were prepared by combining pre-dispersion and high-speed dispersion. The prepared coating specimens were sprayed onto Q235 plates and tinplate plates by simple spraying. Test results show that the addition of modified basalt flakes (MBFs) helps to improve the mechanical and corrosion resistance of the coating. When 30% MBFs were added, the mechanical properties, acid and alkali resistance, and corrosion resistance of the coating reached the best, and the aging resistance was good. Among them, the adhesion of the coating could reach 15.36 MPa, and the coating surface did not show obvious flaring and peeling phenomenon after 1000 h of neutral salt spray test. The water contact angle of the coating increased from 77.77° to 81.31°. Meanwhile, the anti-corrosion performance of the base coating in 3.5 wt% NaCl solution was investigated using electrochemical impedance spectroscopy (EIS). The corrosion current density of the added modified basalt scale coating was in the order of 10−6, which was enhanced by one order of magnitude compared to that of the unmodified basalt scale. The annual corrosion rate of the MBFs coating was only 0.076588 mm·a−1. The superior anticorrosive properties of silane coupling agent-modified basalt flake composite coatings provide a new meaning for the development of anti-corrosive coatings.

Cytokine Activity Indicators Dynamics after Non-Drug Rehabilitation including Intravenous Laser Blood Irradiation in Patients with a Lower Limb Post-Thrombophlebitic Syndrome: a Randomized Study

INTRODUCTION. Previous studies have established the association of venous thrombosis risk factors with inflammation, and the important role of inflammatory mediators as prognostic markers of recanalization of veins after deep vein thrombosis and the progression of postthrombophlebitic syndrome (PTPS). Pro-inflammatory cytokines, as key inflammatory mediators, are part of several cascades of pathophysiology in venous thrombosis, as well as predictors of the occurrence and prolongation of acute thrombosis and its resolution. To date, new oral anticoagulants are used, but their use in medical practice does not lead to a decrease in the number of patients with PTPS.&#x0D; AIM. To study the dynamics of proinflammatory cytokine levels under the influence of a complex non-drug method including intravenous laser irradiation of blood (ILBI) in patients with PTPS.&#x0D; MATERIALS AND METHODS. We conducted a randomized study that included 60 patients aged 58.3 ± 12.56 years with lower extremity PTPS (CVI C4–C5 according to CEAP clinical classification) divided into 2 groups. The subjects of the 1st group (main, n = 30) received: ILBI, pulsed magnetotherapy and dry-air carbon dioxide baths. After a complex of physiotherapy procedures, patients underwent therapeutic gymnastics in the gym according to the Brunner U. method. Subjects of the main group received the above rehabilitation complex against the background of phlebotonics (combination of diosmin and hesperidin) and the use of knitwear of 2–3 compression classes. Patients of the 2nd group (control group, n = 30) received standard elastic compression (2–3 compression class), similar drug therapy with phlebotonics and therapeutic gymnastics in the gym according to the method of Brunner U.&#x0D; RESULTS. After the course of rehabilitation, the patients of the main group showed positive dynamics of the main clinical symptoms of the disease, a decrease in malleolar volume, correction of microcirculatory disorders and activity of proinflammatory cytokines, accompanied by an improvement in transcapillary metabolism and tissue hypoxia. In patients of the control group, only a decrease in the number of leukocytes and fibrinogen in peripheral blood was recorded, while no changes in the expression of proinflammatory cytokines were observed. In this group of subjects, there was a positive trend in the regression of edema in terms of malleolar volume.&#x0D; CONCLUSION. As a result of the application of the proposed rehabilitation complex, which includes, along with the traditionally used physical factors (pulsed magnetotherapy, dry-air carbon dioxide baths and therapeutic gymnastics) ILBI procedures, not only decongestant, hypocoagulating effects, positive dynamics of the main clinical symptoms of the disease were noted, but also correction of microcirculatory disorders and the level of pro-inflammatory cytokines was achieved, accompanied by an improvement in transcapillary metabolism and trophic tissues.

Penerapan Metode Evaluation based on Distance from Average Solution (EDAS) dalam Optimalisasi Layanan dan Pemasaran Coffeeshop

Business owners of coffee shops that fall under the Micro, Small, and Medium Enterprises (MSMEs) employ marketing methods to attract more clients to satisfy the demands and preferences of coffee enthusiasts. However, consumer purchasing behavior demonstrates the difficulty in evaluating marketing performance. In light of this, this study employs the Distance from Average Solution Evaluation Method (EDAS). Meanwhile, coffee shop business brands observed and used as alternatives in this study are Coffee Tanem, 1915 Koffie-Huis, Friends of Coffee Salatiga, Dusk Koffie Salatiga, and Street Side Coffee Salatiga. The results of this study show that the EDAS method can be used to optimize coffee shop business services and marketing as a strategic step in strengthening and improving the performance of the coffee shop business or business. In the context of testing the EDAS decision model, each alternative is assigned a random code (A1-A5). Coffee varieties (C1), aroma and roasted level (C2), serving technique variants (C3), beverage prices (C4), and coffeeshop locations (C5) are often employed as criteria, with categories C1–C3 representing advantages, and C4–C5 representing expenses. Based on the EDAS method's calculation results, it can be seen that the top-ranking coffee shops are those that offer a variety of coffee bean varieties (robusta and arabica), various aromas, and roasted levels (light, medium, dark), various serving methods using espresso machines and manual brew, affordable drink prices, and strategically located coffee shops with enough parking. Thus, it is advised that coffee shop business experts assist in improving capital capabilities and business performance and optimize marketing mix components in STP (Segmenting, Targeting, Positioning) marketing strategies to increase trust, sales volume, consumer satisfaction, and loyalty.

Investigating the uptake and fate of per- and polyfluoroalkylated substances (PFAS) in bean plants (Phaseolus vulgaris): comparison between target MS and sum parameter analysis via HR-CS-GFMAS

In this study, we present a screening method based on molecular absorption spectrometry to study PFAS uptake and fate in plants. To evaluate the suitability of this method we analyzed plant extracts with molecular absorption spectrometry (MAS) as well as liquid chromatography–tandem mass spectrometry (LC–MS/MS) for mass balance studies (w(F)). French bean plants (Phaseolus vulgaris) were grown on soil spiked using eight PFAS substances that vary in chain length and functional group composition. Specifically, these include three short-chained (C4–C5), five long-chained (C7–C10) carboxylic acids, one sulfonic acid and one sulfonic amide moieties. To investigate substance-specific PFAS uptake systematically, PFAS were spiked as single substance spike. Additionally, we studied one mixture of the investigated substances in equal proportions regarding w(F) and four PFAS mixtures of unknown composition. After 6 weeks, the plants were separated into four compartments. We analyzed the four compartments as well as the soil for extractable organically bound fluorine (EOF) by high resolution-continuum source-graphite furnace-molecular absorption spectrometry (HR-CS-GFMAS) as well as for sum of ten target-PFAS by LC–MS/MS. All three short-chained PFAS perfluorobutanoic acid (PFBA), perfluorobutanoic sulfonic acid (PFBS) and perfluoropentanoic acid (PFPeA) were determined in high concentrations mainly in the fruits of the investigated plants while long-chained PFAS perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were mainly determined in roots. PFBS was determined in remarkably high concentrations in leaves compartment by both quantification methods. Overall, comprehensive results of single substance spikes were in good agreement for both methods except for a few cases. Hence, two phenomena were identified: for mixed PFAS spikes of unknown composition huge differences between EOF and sum of target PFAS were observed with systematically higher EOF values. Overall, both methods indicate comparable results with MS being more reliable for known PFAS contamination and MAS being more valuable to identify PFAS exposure of unknown composition.Graphical

Range of motion after 1, 2, and 3 level cervical disc arthroplasty

BackgroundMotion of a solid body involves translation and rotation. Few investigations examine the isolated translational and rotational components associated with disc arthroplasty devices. This study investigates single- and multi-level cervical disc arthroplasty with respect to index and adjacent level range of motion. The investigators hypothesized that single- and multilevel cervical disc replacement will lead to comparable or improved motion at implanted and adjacent levels. MethodsSeven human cervical spines from C2 to C7 were subjected to displacement-controlled loading in flexion, extension, and lateral bending under intact, 1-Level (C5–C6), 2-Level (C5–C6, C6–C7) and 3-Level (C5–C6, C6–C7, C4–C5) conditions. 3D motions sensors were mounted at C4, C5, and C6. Motion data for translations and rotations at each level for each surgical condition and loading mode were compared to intact conditions. Results1-Level: The index surgery resulted in statistically increased translations in extension and lateral bending at all levels with statistically increased translation observed in flexion in the superior and inferior levels. In rotation, the index surgeries decreased rotation under flexion, with remaining levels not statistically different to intact conditions. 2-LevelA device placed inferiorly resulted in statistically increased translations at all levels in extension with statistically increased translations superior and inferior to the index level in flexion. Lateral bending resulted in increased nonsignificant translations. Rotations were elevated or comparable to the intact level for all loading. 3-LevelTranslations were statistically increased for all levels in all loading modes while rotations were elevated or were comparable to the intact level for all loading modes and levels. ConclusionsMicromotion sensors permitted monitoring and recording of small magnitude angulations and translations using a loading mechanism that did not over constrain cervical segmental motion. Multilevel cervical disc arthroplasty yielded comparable or increased overall motion at the index and adjacent levels compared to intact conditions.

Atypical extravertebral ventral cervical disc extrusion in a dog

AbstractA 6‐year‐old cocker spaniel dog was investigated by computed tomography for a marked neck pain more evident on ventroflexion. Cervical disc extrusion of mineralised nucleus pulposus material was identified in the vertebral canal dorsally to the C4–C5 intervertebral space, with spinal cord compression. Another mineralised material was also identified at an unusual location, ventrally to the C2–C3 intervertebral space. Ventral slot at C4–C5 intervertebral disc allowed surgical removal of the compressive disc, and longus colli muscles dissection at C2–C3 level allowed removal of the identified material, confirmed histologically as degenerated (mineralised) nucleus pulposus. Ventral paravertebral disc extrusion of degenerated nucleus pulposus extrusion is rarely described in human medicine. This case report illustrates the anatomical and imaging key points that support the diagnostic approach to a previously undescribed presentation of disc extrusion in dog.

Reaction Pathways of Gamma-Valerolactone Hydroconversion over Co/SiO2 Catalyst

The hydroconversion of γ-valerolactone (GVL) over Co/SiO2 catalyst proceeds in a complex reaction network, resulting in 2-methyltetrahydrofuran (2-MTHF) as the main product, and C4–C5 alcohol and alkane side-products. The catalyst was shown to contain Co0 sites and Lewis acid (Co2+ ion)/Lewis base (O2− ion) pair sites, active for hydrogenation/dehydrogenation and dehydration reactions, respectively. The initial reaction step was confirmed to be the hydrogenation of GVL to key intermediate 1,4-pentanediol (1,4-PD). Cyclodehydration of 1,4-PD led to the main product 2-MTHF, whereas its dehydration/hydrogenation gave 1-pentanol and 2-pentanol side-products, with about the same yield. In contrast, 2-pentanol was the favored alcohol product of 2-MTHF hydrogenolysis. 2-Butanol was formed by decarbonylation of 4-hydroxypentanal intermediate. The latter was the product of 1,4-PD dehydrogenation. Alkanes were formed from the alcohol side-products via dehydration/hydrogenation reactions.

The Formation of Small Amounts of Cyclopropane during Pulsed Pyrolysis of C4–C5 Acyclic Alkanes in the Adiabatic Compression Reactor

During high-temperature pulse pyrolysis of acyclic butanes and pentanes under adiabatic compression conditions, cyclopropane, a stressed cyclic hydrocarbon, was found among the reaction products in small quantities for the first time. The analysis of the reaction products was performed by gas chromatography using three capillary columns of different polarity, selectivity and sufficient efficiency. The identification of reaction products, including cyclopropane, was performed using retention times of individual substances and model mixtures, as well as comparing chromatograms with reference chromatograms from the literature and the ScanView Application Database. It was shown that the chromatographic peak attributed to cyclopropane could not be a ghost peak. Additional confirmation of this conclusion was obtained in a series of experiments on the pyrolysis of n-butane at a reduced initial temperature of the adiabatic compression reactor (from 120 °C to 50 °C) and a modified mode of GC analysis. Cyclopropane yields as a function of maximum temperature have a bell-shaped asymmetric dependence. The maximum value of the yield of cyclopropane increases with the transition from normal alkanes to isoalkanes, and from pentanes to butanes; for n-pentane, 0.009 wt. %, and for isobutene, ≈0.017 wt. %. During the pulse pyrolysis of isobutane, n-butane, isopentane and n-pentane, cyclopropane is not a primary product. Further theoretical and experimental studies are needed to establish the mechanism of cyclopropane formation during pyrolysis of C4–C5 acyclic alkanes.

Outpatient minimally invasive spine surgeries during the COVID-19 pandemic – A retrospective analysis of 164 consecutive cases

ObjectiveTo share our surgical experiences of minimally invasive cervical and lumbar procedures for patients who suffered from non-fatal motor vehicle accidents (MVAs) in the ambulatory surgery centers (ASCs) during the coronavirus disease 2019 (COVID-19) pandemic. MethodsAnterior cervical discectomy and fusion (ACDF), anterior lumbar interbody fusion (ALIF), minimally invasive laminotomy and discectomy (MILD), percutaneous endoscopic laser-assisted discectomy (PELD) and percutaneous kyphoplasty (PK) were performed on carefully selected patients. ResultsFrom January 2020 to December 2021, our group performed 164 cases on 153 patients involving 249 intervertebral disc (IVD) levels. Of these, 116 cases (70.73%) on 114 patients (74.51%) were cervical, 48 cases (29.27%) were lumbar (including 8 PK cases). Eight patients had both cervical and lumbar procedures in a single anesthetic session (SAS) and were discharged on the same day. One hundred and six ACDF cases (92.17%) were at the C4–C5 and C5–C6 levels, which comprised of 146 (76.04%) IVDs. Of the 40 non-PK lumbar cases, 38 (95.0%) were at L4 to S1 lumbar levels. Six of these cases (15.0%) involved 2 lumbar levels. In contrast, 6 out of 8 kyphoplasties (75.0%) involved lower thoracic/higher lumbar vertebral columns (T11 to L2) and 2 were at the lower lumbar L4 level. ConclusionsWe successfully and safely performed various cervical and lumbar spine surgeries in the ASCs amid COVID-19 pandemic and all patients achieved the same-day discharge (SDD). In the non-fatal MVAs, mid-lower cervical (C4 to C6) and lower lumbar (L4 to S1) IVDs were the most affected levels.

Biomechanical analysis of a single-level customized cage screw fixation for anterior cervical discectomy and fusion in the cervical spine: an in-silico study

The usual surgical choice of customized cage fixation is anterior cervical discectomy and fusion (ACDF) for cervical spondylosis with disc herniation. The safe and successful cage fixation for ACDF surgery benefits patients with cervical disc degenerative disease by easing their discomfort and regaining function. The cage prevents mobility between the vertebrae by using cage fixation to anchor the neighbouring vertebrae. The goal of the current study is to develop a customized cage-screw implant for single-level cage fixation at C4–C5 level of the cervical spine (C2–C7). The Finite Element Analysis (FEA) is performed for the intact and implanted cervical spine and analysed the flexibility, stress of the implant and implant adjacent bone during three physiological loading conditions being analysed. Lower surface of the C7 vertebrae is fixed and 50 N compressive force with 1 Nm moment are applied on the C2 vertebrae for simulated lateral bending, axial rotation and flexion-extension. The flexibility is decreased at single level of fixation (C4–C5 level) by 64% to 86%, as compared to natural cervical spine. The flexibility is increased 3% to 17% at the nearest levels of fixation. The maximum Von Mises stress in PEEK cage varies from 24 to 59 MPa and for Ti-6Al-4V screw the stress varies from 84 MPa to 121 MPa which are far below the yield stress of PEEK (95 MPa) and Ti-6Al-4V (750 MPa).

Hydroformylation of Lower Olefins and the Use of Oxo Synthesis Products Based on C4–C5 Aldehydes in the Production of Ester Lubricating Oils. Part 1. Catalysts and Industrial Processes

Hydroformylation of Lower Olefins and the Use of Oxo Synthesis Products Based on C4–C5 Aldehydes in the Production of Ester Lubricating Oils. Part 1. Catalysts and Industrial Processes

Study of the Effect of Anodic Oxidation on the Corrosion Properties of the Ti6Al4V Implant Produced from SLM.

Additive technologies allowed for the development of medicine and implantology, enabling the production of personalized and highly porous implants. Although implants of this type are used clinically, they are usually only heat treated. Surface modification using electrochemical methods can significantly improve the biocompatibility of biomaterials used for implants, including printed ones. The study examined the effect of anodizing oxidation on the biocompatibility of a porous implant made of Ti6Al4V by the SLM method. The study used a proprietary spinal implant intended for the treatment of discopathy in the c4-c5 section. As part of the work, the manufactured implant was assessed in terms of compliance with the requirements for implants (structure testing-metallography) and the accuracy of the pores produced (pore size and porosity). The samples were subjected to surface modification using anodic oxidation. The research was carried out for 6 weeks in in vitro conditions. Surface topographies and corrosion properties (corrosion potential, ion release) were compared for unmodified and anodically oxidized samples. The tests showed no effect of anodic oxidation on the surface topography and improved corrosion properties. Anodic oxidation stabilized the corrosion potential and limited the release of ions to the environment.

Modeling of Erosion in a Cyclone and a Novel Separator with Arc-Shaped Elements

Modeling of the separation of catalyst particles from gas using two devices, a cyclone and a novel separator with arc-shaped elements, was performed for fluidized-bed dehydrogenation of C4–C5 paraffins to isoolefins as an example. The proposed dust collector allows one to reduce erosive wear by several times (~6.5-fold) in identical regimes and at identical parameters of the process. The effect of particle size on erosive wear was analyzed under near-industrial conditions; the regions most susceptible to wear in the analyzed devices were identified, as well as the functions describing the dependence between the erosive wear rate and particle diameter for the cyclone and separator with arc-shaped elements, making it possible to predict wear in the devices were obtained.