Stability Of Column Research Articles

Technical Feasibility and Safety of Transpedicular Thoracic Partial Corpectomy Using Biportal Endoscopic Technique: A Novel Approach for Separation Surgery in Spinal Metastatic Disease.

Bony metastases frequently involve the spinal column, most commonly the thoracic spine.1 Surgical interventions in spinal metastatic disease are palliative and effective in providing diagnoses, reducing pain, and maintaining ambulatory function through neural element decompression and improving axial pain and posture through spinal column stabilization. Surgeons must weigh the benefits of surgery against fragility and limited life expectancy in patients with cancer.2,3 Minimally invasive techniques such as tubular and endoscopic approaches modulate preoperative risk profiles by disrupting less tissue, which may hasten time for postoperative recovery and time to radiation and systemic therapy for disease control.4,5 Advancements in surgical technique and technology have expanded endoscopic indications in spinal oncology. Indications have evolved from biopsy and hybrid open minimally invasive surgery approaches to fully endoscopic separation surgery and gross total resection of nonmetastatic tumors.6-10 In the case presented in Video 1, we used a biportal endoscopic technique to separate an unstable T12 retropulsed burst fracture from the ventral thoracic spinal cord. The biportal endoscopic technique allowed use of standard instruments for partial corpectomy such as osteotomes, rongeurs, and drills assisted by endoscopic visualization. Minimally invasive surgery percutaneous instrumentation was performed to stabilize the spinal column. Postoperative imaging showed improved spinal alignment and adequate spinal canal decompression, which allowed the patient to be discharged on postoperative day 4 without wound complications and undergo stereotactic body radiation therapy. The patient consented to this procedure, and identifiable individuals consented to publication of their image.

Comfort in stratification and trophic flexibility: argentine anchovy, Engraulis anchoita, larvae life traits in relation to their food sources

Fish larvae feeding success is crucial for adult recruitment, which affects both fisheries and ecosystem regulation processes. Engraulis anchoita is a species of great ecological and fishing relevance in the South-West Atlantic Ocean, with a wide latitudinal distribution and active spawning throughout the year and strongly associated with frontal areas. E. anchoita larvae have been described as exclusively feeding on small copepods and their early developmental stages. In this study, the diet, nutritional condition, and daily growth of E. anchoita larvae were estimated in different environmental scenarios in the South-West Atlantic Ocean. Carbon and Nitrogen stable isotopes analysis, otolith microstructure analysis, and RNA/DNA index determination were performed. The larval diet, which was evaluated based on the availability of potential prey, varied with respect to the water column stability. It was observed that the larvae tend to feed on microphytoplankton in stratified waters and on calanoid copepods in waters with a homogeneous vertical structure. The growth and nutritional condition indexes responded to ontogeny, presenting higher values at larger larval sizes. Growth indexes also responded positively to the stratified water column structure in comparison to the homogeneous one. The nutritional condition index was only explained by the size of the individuals. This study found that E. anchoita larvae had greater trophic flexibility than previously suspected, as they included microphytoplankton as the main food item under certain oceanographic conditions without negative impacts on their growth or nutritional condition.

Biomechanical study of two different fixation methods for the treatment of Neer III proximal humerus fractures

BackgroundThe lateral locking plate for the proximal humerus is currently the most commonly used surgical procedure for the treatment of elderly proximal humeral comminuted fractures. Previous studies have found that the rate of postoperative complications in patients of proximal humerus fractures with medial column involvement is relatively high. Through biomechanical methods, this study aims to investigate the effectiveness of the conventional lateral locking plate fixation along with the addition of the metacarpal supporting plate on the medial column in the treatment for proximal humeral fractures involving the medial column. The goal is to reduce the rate of postoperative internal fixation failure in patients with medial column injury.MethodsThirty artificial synthetic humerus models are used as experimental samples. A proximal humerus fracture model with medial column injury was created, and then divided into two groups. Group A was fixed with a proximal humerus lateral locking plate (single-plate group). Group B was fixed with a proximal humerus lateral locking plate and a metacarpal supporting plate on the medial column (double-plate group). The failure displacement, stiffness, and strength of the repaired proximal humerus fractures with two different methods were tested under compression at posterior extension of 15°, forward flexion of 15°, and vertical direction.ResultsThere was no statistical significance in the comparison of the failure displacement of repaired proximal humeral fractures between the two groups under compression at posterior extension of 15° and forward flexion of 15° (P > 0.05). However, the failure displacement of the fracture was longer in single-plate group than in double-plate group under compression at vertical direction (P < 0.05). The double-plate group was better in terms of biomechanical stiffness and strength compared to the single-plate group at all three testing angles (P < 0.05).ConclusionsFor patients whose proximal humeral fractures involve the medial column, the addition of a support plate on the medial side of the humerus is recommended along with the lateral locking plate. The double-plate strategy can increase the stability of the medial column of the proximal humerus, and enhance the overall biomechanical property of the repaired proximal humerus.

Sequential Anterior Longitudinal Ligament Release With Expandable Spacers for Lordosis Correction in Anterior-to-Psoas Lumbar Interbody Fusion: A Radiographic and Biomechanical Study.

Anterior column realignment is an attractive minimally invasive treatment for sagittal imbalance. Expandable spacers offer controlled tensioning of the anterior longitudinal ligament (ALL) during release, which could optimize correction and anterior column stability. This study investigated the biomechanical and radiographic effects of single-level anterior-to-psoas lumbar interbody fusion (ATP-LIF) with expandable spacers and sequential ALL release. In vitro range of motion tests were performed on 7 fresh-frozen cadaveric spines (L2-L5) with a ±7.5 Nm load applied in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). After testing intact spines, single-level (L3-L4) ATP-LIFs were performed and supplemented with posterior screws, rods, and integrated lateral screws and tested after (1) no ALL release (ATP-LIF); (2) resection of 1/3 the ALL's width (1/3 ALL release); (3) resection of 2/3 the ALL's width (2/3 ALL release); and (4) complete ALL resection (3/3 ALL release). Following each partial ALL release, rods were removed, and spacers were expanded until the torque limit was reached. Rods were then reapplied, and lateral radiographs were taken to analyze changes in intervertebral angle (IVA), foraminal height, foraminal area, and posterior and anterior disc height (PDH and ADH). In ATP-LIF constructs, range of motion decreased in FE (18% intact), LB (14% intact), and AR (30% intact), while IVA, PDH, ADH, foraminal height, and foraminal area increased. PDH and ADH increased linearly with sequential ALL release and spacer expansion, while LB and AR remained stable. FE increased slightly (+15%-16% intact, <1°) following 2/3 ALL release but remained stable afterward. IVA increased exponentially with sequential ALL release, gaining 8.8° ± 3.2° with complete release. The present study found improved biomechanics and radiographic parameters following ATP-LIF with intact ALL, minimal biomechanical differences between partial and complete ALL release, and greater correction and height restoration with complete release. Future clinical testing is necessary to determine the impact of this finding on patient outcomes. Controlled tensioning of the ALL before and after ligament release allows for potential optimization between restoring sagittal balance and maximizing construct stability in a minimally invasive approach.

Thermohaline Intrusions as Seen by Argo Floats: The Case of the Black Sea

AbstractUnderstanding the dynamics of thermohaline intrusions is crucial for predicting changes in water masses and their impact on marine ecosystems, especially in highly stratified semi‐enclosed seas and other coastal environments. We use high‐resolution (up to 1–2 m) Argo profiling float data collected over 15 years in the Black Sea, an excellent test area for studying thermohaline intrusions. Our analysis challenges the conventional view of stagnant intermediate and deep waters, revealing active mixing processes that reshape the thermohaline structure. We identified two main mechanisms driving these intrusions, related to dense water inflows from the Marmara Sea and boundary mixing enhanced by frontal instabilities. Argo data also allowed us to identify areas with favorable conditions for double‐diffusive processes. The variability of intrusions is due to changes in the thermohaline state of the upper ocean as well as to quasi‐periodic changes in the inflow caused by local conditions. Trends in the intensity and frequency of intrusions indicate shifts in water mass properties that are likely to be associated with climate variability and extreme weather events. Such trends can affect nutrient cycling, oxygen distribution and the overall stability of the water column, thereby affecting biogeochemical cycles and the resilience of marine ecosystems. Similar ventilation mechanisms may operate in other highly stratified marine systems, such as the Baltic Sea and the Arctic Ocean, so our findings may have wider implications for understanding climate‐induced changes in water masses at regional and global scales.

Fabrication and application of aminated metal–organic cages doped monolithic column for pipette tip micro solid-phase extraction of eight phenolic compounds in milk

A Zr-based metal–organic tetrahedron (ZrT-1-NH2) doped monolithic column was sythesized and applied for pipette tip micro solid-phase extraction (PT-μSPE) of 8 phenolic compounds. Scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis and N2 adsorption and desorption experiment were employed to characterize the morphology, composition, structure and thermal stability of the monolithic column. The experimental results showed that the monolithic column had good stability and excellent adsorption selectivity for phenolic compounds. The adsorption mechanism was speculated to be π-π stacking and H-bond interaction based on ESP maps. After the extraction conditions were optimized, a PT-μSPE-high performance liquid chromatography-ultraviolet detector (HPLC-UV) method was established for the detection of 8 phenolic compounds in milk. The PT-μSPE-HPLC-UV method has wide linearities (0.3–1000 μg L−1) (R2 > 0.997), low limits of detection (0.1–0.3 μg L−1), satisfactory recoveries (80.5–113.6 %) and high precision (RSDs < 6.7 %). Thus, the ZrT-1-NH2 doped monolithic column is an ideal medium for the separation and determinaton of phenolic compounds in milk.

A Strong Link Between Oceanographic Conditions and Zooplankton δ13C and δ15N Values in the San Jorge Gulf, Argentina

Maps of (baseline) δ13C and δ15N values of primary producers or consumers near the base of food webs provide crucial information for interpreting patterns in the isotopic composition of consumers that occupy higher trophic levels. In marine systems, understanding how oceanographic variables influence these values enables the creation of dynamic isoscapes across time and space, providing insights into how ecosystems function. The San Jorge Gulf (SJG) in the southwest Atlantic Ocean (45° S–47° S) is an area of particular importance, as it is located on one of the most productive continental shelves in the world, supporting large fisheries and marine mammal and seabird populations. We reconstructed spatial variation in zooplankton δ13C and δ15N values across SJG and investigated their relationship with physical and chemical oceanographic conditions. During cruises in the austral spring of 2016 and 2017, we collected medium-sized copepods whose isotopic composition integrate short-term (days to weeks) variation in oceanographic conditions recorded by phytoplankton at the base of the food web. We also collected data on water column depth, surface and bottom temperatures, water column stability, and macronutrient (nitrate, phosphate, and silicic acid) concentrations. The results revealed significant variation in both δ13C and δ15N values of up to 7-8‰ over a relatively small spatial scale (200–300 km). Copepod δ13C values were lower at the center of the SJG, showing an inverse correlation with water column stability, surface nitrate concentration, and water column depth. δ15N values showed a strong and negative relationship with surface nitrate concentration and water column stability, increasing from south to north in the SJG. δ15N values also showed a positive relationship with surface silicic acid concentration. These spatial patterns in nutrient dynamics and copepod carbon and nitrogen isotope values are interpreted in the context of the dominant northward current and temporal development of the frontal systems in the SJG.

Glutathione-functionalized covalent organic frameworks@silica as a hydrophilic-hydrophobic balanced mixed-mode stationary phase for highly efficient separation of compounds with a wide range of polarity

BackgroundCovalent organic frameworks (COFs) are a highly promising stationary phase for high-performance liquid chromatography (HPLC), but the separation of polar compounds is limited by their low hydrophilicity. Therefore, it is crucial to develop novel COFs-based stationary phases with balanced hydrophilicity-hydrophobicity for the efficient separation of different polar compounds. ResultsIn this paper, glutathione (GSH)-functionalized COFs@silica microspheres (GSH-COFs@SiO2) were synthesized via a two-step, post-synthesis modification strategy. The COFs particles was constructed onto silica surface by the covalent conjugation of 1,3,5-tris(4-aminophenyl)benzene and 2,5-divinylterephthalaldehyde. GSH containing abundant –NH2 and –COOH groups was bonded onto the surface of COFs@SiO2 to further enhance hydrophilicity. The resulting GSH-COFs@SiO2 exhibited balanced hydrophilicity-hydrophobicity and can be used in hydrophilic/reversed-phase liquid chromatography modes through multiple retention mechanisms. Consequently, a variety of compounds with different polarity, including nucleosides/bases, benzoic acids, anilines, phenols, alkylbenzenes and polycyclic aromatic hydrocarbons, were well separated with ideal resolution, satisfactory column efficiency and good peak shapes. Furthermore, this novel column exhibited remarkable column stability, as evidenced by intra-day relative standard deviations of 0.08 %–0.18 % for retention time and 0.45 %–1.47 % for peak area. Significance and noveltyThis work demonstrates the superior hydrophilic-hydrophobic selectivity of GSH-COFs@SiO2 stationary phases towards compounds with a wide range of polarity and provides a very facile and easily popularized post-synthetic modification route for hydrophilic-hydrophobic balanced COFs-based HPLC stationary phases.

Meta-Analysis Investigating Optimal Timing of Chemoprophylaxis for Venous Thromboembolism in Operatively Managed Blunt Spinal Injuries.

Blunt spinal injuries (BSIs) are associated with substantial morbidity and mortality. Management typically involves stabilization of the spinal column and may include chemoprophylaxis for venous thromboembolism (VTE) prevention. The optimal timing of chemoprophylaxis initiation in operatively managed BSI patients remains debated. Analyze available literature on optimal chemoprophylaxis timing for the prevention of VTE in patients postinjury undergoing operative repair. Systematic review and meta-analysis. A systematic review and meta-analysis were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed and MEDLINE were searched for studies assessing chemoprophylaxis timing in adult BSI patients. Inclusion criteria focused on operatively managed BSIs and anticoagulant usage assessment. Three studies involving 4345 patients were included. Early chemoprophylaxis initiation was associated with significantly lower deep vein thrombosis (DVT) and overall VTE incidence compared with late initiation. No significant differences were found in pulmonary embolism (PE) incidence or mortality. Early anticoagulant administration after spinal fixation for BSI reduces DVT and overall VTE risk without impacting PE incidence or mortality. Further research is recommended to solidify these findings and address existing gaps in the literature. Early chemoprophylaxis initiation in operatively managed BSI patients reduces DVT and overall VTE risk without affecting PE incidence or mortality LEVEL OF EVIDENCE: 2.

Axial compressive behavior and capacity prediction of concrete-filled cold-formed lipped channel PEC stub columns

The stability and capacity of thin-walled steel columns can be considerably upgraded by filling concrete into hollow spaces surrounded by cold-formed lipped channel (CLC) and external battens. However, there is limited experimental data available, especially for the axial compression behavior of concrete-filled CLC partially encased composite (PEC) columns. This paper aims to investigate the compressive behavior of CLC-PEC short columns and presents an analytical model for predicting the axial capacity of the column. The study explores the influences of cross-sectional dimensions and external batten plate configurations on the compressive performance of CLC-PEC columns through axial compression tests conducted on 12 short column specimens. The results indicate that the failure modes of the specimens involve localized concrete spalling on the exposed side at the lower part of the column, along with a elephant foot-shaped buckling of the cold-formed steel lipped channel. The damage surface of the confined concrete was obtained by circumferential cutting of the buckling location. The findings highlight the significant influence of the character of the CLC section on the ineffectively confined area at the failure surface, with a dumbbell-shaped effective confinement zone revealing the presence of a highly confined area. Based on the calibrated failure surfaces, a numerical model-based study of the axial stress distribution in the concrete core was then carried out to estimate the confinement effect of the columns under peak loading. The study employed multiple regression analysis to quantify the area ratio of the confined zone to the concrete core based on finite element analysis (FEA) results from 143 CLC-PEC columns. The proposed model was evaluated against test results and found to be more reliable than axial compression loads based on the superposition strength method. The proposed axial capacity of short columns takes into account the slenderness ratio of each member.

Driving factors of phytoplankton Reynolds functional groups (RFGs) in a subtropical reservoir (São Paulo, Brazil)

Subtropical reservoirs are susceptible to the eutrophication process, largely due to inappropriate land use and occupation in the watersheds, resulting in changes in the composition of the phytoplankton community, according to the sensitivity and environmental tolerances of the different species. Application of the Reynolds functional groups (RFGs) method to the multispecies phytoplankton community is a valuable approach that can be used to answer ecological questions at different spatial and temporal scales. The Itupararanga reservoir, in the upper Sorocaba River basin (São Paulo state, Brazil), is used to supply drinking water to approximately one million people, as well as for agricultural and recreational purposes. This study examines the relationships between environmental variables and the composition of the phytoplankton community, identifying the main functional groups (RFGs) along a spatial gradient in the reservoir (from upstream to downstream), during one year. Five samplings were performed at seven points in the reservoir, in the rainy and dry seasons (from 2016 to 2017). The effects of spatial heterogeneity influenced the formation of different biomass gradients for each functional group. The most abundant RFGs were Sn (warm mixed environments), H1 (eutrophic, both stratified and shallow lakes with low nitrogen content), and Lo (deep and shallow, oligotrophic to eutrophic, medium to large lakes), which corresponded to the spatial heterogeneity of the reservoir. The variables with the greatest influence on the phytoplankton composition in the reservoir were total nitrogen, nitrite, and the N/P ratio, with phosphorus as the limiting nutrient. The presence of Cyanobacteria (codons Sn and H1) was driven by the stability of the water column, due to the long residence time of the water in the reservoir. This research demonstrated the effectiveness of using RFGs as environmental descriptors, providing an essential tool in aquatic ecology studies.

Surgical Treatment of Primary Spinal Tumors

Primary spinal tumors appear to be much less common than metastatic lesions, but their surgical treatment comprises a complex and multifaceted task. Numerous factors influence indications and timing of surgical intervention, including neurological status of the patient, histological characteristics of the tumor, its localization, stability of the spinal column, and comorbidities. Significant spinal cord compression, rapid progression of neurologic deficits, or pronounced instability of the spinal column may require urgent surgical intervention. When the spinal canal is not affected, treatment should start with a biopsy to accurately determine the histology of the tumor. Some tumor types, such as giant cell tumors, osteoblastomas, chordomas, and chondrosarcomas, require complete removal of the tumor. However, performing a wide resection in a single block is often found difficult due to compression of vascular and nerve structures. Current approaches to surgical management of primary spinal tumors involve minimally invasive techniques that significantly improve postoperative recovery and reduce the risk of complications. These techniques were originally used to treat degenerative spinal diseases and trauma; however, they have also demonstrated their effectiveness in tumor surgery. Adapting surgical strategy based on histology and tumor location, as well as integrating minimally invasive techniques, can improve patient survival and quality of life. The present paper describes the latest advances in the surgical treatment of primary spinal tumors, discusses current techniques and strategies, and prospects for further research in this area.

Stability of slender GFRP tube-confined UHPC-filled steel-encased column under axial compression: Experiment and mesoscale modeling

The stability of GFRP tube-confined UHPC-filled steel-encased columns (FUSCs) is critical for optimal utilization of its superior cross-sectional load-bearing capacity that guarantees overall structural safety. This study conducted an experimental investigation on 14 slender FUSC specimens under uniaxial compression for different aspect ratios and aggregate contents. The pressure-sensing films were applied to measure the contact pressure between the GFRP tube and UHPC, and a mesoscale finite element model was developed to uncover the role of randomly distributed fibers and aggregates in the UHPC during the failure process. Accordingly, the stability performance of slender FUSC was analyzed, and specific discussions were held on the mutual interaction mechanism between GFRP and UHPC during the loading process. The results showed that the stability of FUSCs decreased faster with an aspect ratio of l0/D > 8 (λ>30.77), resulting in the decrease of load-carrying capacity for up to 25 %. By including coarse aggregate, the distribution of steel fibers was densified, and Young's Modulus of UHPC was increased, considerably improving the stability of FUSCs. Moreover, the GFRP tube with a fixed winding angle of 50° remarkably enhanced the stability of the specimen due to the sharing of bending moment instead of providing confinement. This research outcome offers a basis for the stability control of slender FUSCs.

Stability of a Non-uniform Column resting on a Foundation, calculated with the Finite Element Method

Stability of a Non-uniform Column resting on a Foundation, calculated with the Finite Element Method

Bridged Ethylene Polyethylene Oxide Surfaces to Improve Packing Materials for Widepore Size Exclusion Chromatography.

Here, we describe the preparation of bridged ethylene polyethylene oxide (BE-PEO) surface-modified silica packing materials for size exclusion chromatography. BE-PEO surface-modified silica was hydrolyzed and subsequent 1H nuclear magnetic resonance analysis of hydrolysis products confirmed the successful formation of BE-PEO bonded surface. Silica particles exhibiting 3µm diameters and 1000 Å nominal pore diameters were selected as a base material for this work out of the critical need to improve analytical capabilities for the testing of cell and gene therapy drug products. Accelerated high pH aging study revealed significant enhancement in column stability. Multi-angle light scattering noise measurements showed inordinately lower baseline noise. Moreover, we evaluated the chromatographic performance of BE-PEO silica-packed columns through separations of a protein test mixture, DNA ladder, monoclonal antibody-based therapeutics, and adeno-associated viruses. BE-PEO silica columns demonstrated high resolution, high recovery separations that were confirmed to be reproducible and capable of extended column lifetimes and exhibited low ionic and hydrophobic secondary interactions. In summary, BE-PEO silica particles have yielded a new level of performance, improved base stability, and inherently lower baseline noise. These novel widepore particles will facilitate more sensitive size-based detection and characterization of large biologics in the form of advanced gene therapy products.

The Cutting Edge of Charcot Reconstruction: Anatomical Osteotomies Benchmarking Optimal Survivorship in Charcot Reconstruction

Category: Diabetes; Midfoot/Forefoot Introduction/Purpose: Charcot neuroarthropathy is a debilitating condition that frequently leads to skeletal instability, deformity and an increased risk of ulceration leading to infection. This often necessitates prolonged periods of immobilization and casting. Nonetheless, opting for reconstruction presents an opportunity for limb preservation and the potential for weight-bearing functionality, contrasting starkly with the higher mortality rates associated with amputation. Methods: We present findings from a prospective study involving 102 patients who underwent Charcot reconstruction surgery conducted by two experienced surgeons from May 2014 to Oct 2024. Our approach incorporated advanced techniques such as 3D modeling and standardized osteotomies, including the King’s Cut and ARK osteotomy, to achieve precise anatomical corrections of Meary’s angle, as well as the anterior-posterior and lateral talo-calcaneal angles, along with calcaneal pitch. Additionally, patients underwent either primary or staged reconstruction in cases where osteomyelitis was suspected due to pre-existing ulceration. Definitive stabilization was achieved through internal fixation targeting the stabilization of unstable foot columns. A multivariate analysis was conducted to evaluate potential risk factors associated with failure, with statistical significance determined at P&gt;0.05. Survivorship was defined by the absence of ulceration, catastrophic failure, or the necessity for amputation. Results: In the study, 79 feet were analyzed, with 46 undergoing single-stage and 43 two-stage reconstruction. Predominantly male (62.7%) with an average age of 56 years, most patients (89.63%) had type 2 diabetes, 56% hypertension, and 16% chronic kidney disease requiring dialysis. Among single-stage reconstructions, 52.1% had pre-operative ulcers, 13 ischemic heart disease, and 56 peripheral artery disease. 81% achieved normalized angles (P &lt; 0.05); 3.4% required further surgery for infection, 17.9% experienced delayed wound healing. Survivorship rates were 98% at 3 years and 94% at 6 years, higher for those with vascular disease. At final follow-up, all maintained mobility, contributing to an overall 94.4% survivorship at 6 years, with 98% achieving ambulatory weight-bearing in shoes at 2 years. Conclusion: Strategic patient selection, multidisciplinary teamwork, and precise anatomic reconstruction, rather than merely achieving a plantigrade foot, are pivotal factors in achieving consistent and predictable outcomes for functional limb salvage. Research evidence underscores the importance of addressing pre-operative vascular compromise, as it significantly influences survivorship rates.

Peritalar Parameters in Medial Column Collapse: 3D Analysis Distinguishing Midfoot Arthritis and Progressive Collapsing Foot Deformity

Category: Midfoot/Forefoot; Hindfoot Introduction/Purpose: Midfoot arthritis (MA) and progressive collapsing foot deformity (PCFD) are both entities characterized by biomechanical changes of the foot leading to collapse of the medial arch. The effect of PCFD on peritalar dislocation/subluxation has been described extensively and is a critical consideration in preoperative planning of deformity correction. While midfoot arthritis has been previously associated with subluxation of the midfoot joints such as the naviculocuneiform and tarsometatarsal joints, no studies have evaluated the effect of midfoot arthritis medial column collapse on peritalar parameters. The primary objective of this study was to compare the extent of medial arch collapse in MA and PCFD and correlate these parameters with peritalar changes. Methods: This is a retrospective comparative study identifying patients with PCFD and MA. PCFD was defined as a known history of flatfoot deformity and symptomatic progression of medial arch collapse. Midfoot arthritis was identified through radiological findings along with patient-reported symptomatic medial arch collapse. Patients with both flat foot deformity and radiological findings of midfoot arthritis were excluded. All patients underwent foot/ankle Weightbearing computed tomography (WBCT). Manual and semi-automated 3D measurements of the middle facet subluxation percentage, middle facet incongruence angle, foot &amp; ankle offset, forefoot arch angle, and transverse arch plantar angle were performed. Measurements were done independently by two fellowship-trained readers. Variables were assessed for normality (Shapiro-Wilk) and compared using Paired T-tests or Wilcoxon signed rank test. P-values of 0.05 or less were considered significant. Results: A total of 28 feet were analyzed (14 extremities with PCFD and 14 extremities with MA). The difference in middle facet subluxation percentage and middle facet incongruence angle were statistically significant between the 2 groups favoring more peritalar subluxation in the PCFD group as compared to the MA group (38 vs 14.1 p-value &lt; 0.001 and 12.5 vs 4.1 p-value &lt; 0.001, respectively). The forefoot arch angle was significantly lower in the PCFD group (2.8 vs 6.6, p-value &lt; 0.005) No significant difference was identified in the transverse arch plantar angle between the groups (125.5 vs 121.6, P-value: 0.2). Conclusion: In this retrospective comparative study, midfoot arthritis was found to have a limited effect on peritalar parameters in the setting of medial arch collapse. This study demonstrated that the deformity associated with midfoot arthritis is confined to the medial column and does not affect peritalar subluxation, unlike PCFD. These data demonstrate for the first time that midfoot arthritis and PCFD require distinct approaches in order to address medial column stability in order to achieve the required restoration in foot alignment.

Analysis of strength and resistance to loss of stability of thin-walled channel columns with non-standard cross-sectional shape

Analysis of strength and resistance to loss of stability of thin-walled channel columns with non-standard cross-sectional shape

The geochemical and thermodynamic characteristics of waste sand reinforced by microbially induced calcium carbonate precipitation

To achieve efficient utilization of waste sand and make it a recyclable resource, the waste sand was reinforced by microbially induced calcium carbonate precipitation (MICP). Scanning Electron Microscopy (SEM)–Energy Dispersive Spectrometer (EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to determine the mineral morphologies and elemental compositions. The results of SEM showed that rhombohedral and dumbbell-shaped minerals filled the pores of the sand column, and the elemental compositions were C, O, Ca, Al, and P. Various organic functional groups were discovered by FTIR. Mineral compositions were analyzed by X-ray diffraction (XRD). The results showed that the mineral components were calcite and aragonite, and the crystallinity of calcite improved with the increase in the bacterial concentrations. Stable carbon isotope analyses showed that the sand columns at different bacterial concentrations ranged from − 18.9 ‰ to − 21.4 ‰, which were more negative than chemical calcite with − 10.9 ‰. The mechanical properties of compression strength and splitting tensile strength proved that MICP could enhance the strength of sand columns. Thermodynamic characteristics were carefully investigated using thermogravimetric analysis from 50 °C to 1000 °C, which showed that the activation energy and thermal stability of the sand columns reinforced by MICP increased. Therefore, this study provides important insights into the process of MICP, which has good spontaneity, ecological performance, and low energy consumption. It is conducive to the construction of ecological civilization and the requirements of green development, and it has important engineering significance.

Evaluation of an Extraction Chromatographic Resin Based on the DOODA Extractant: Characterization, Comparison to DGA, and Potential Applications

ABSTRACT The extraction of selected metal ions by an extraction chromatographic (EXC) resin containing N,N,N’,N’-tetraoctyl-3,6-dioxaoctane diamide (DOODA) on a porous methacrylate support was measured from nitric acid and hydrochloric acid. Metal ion extraction with the DOODA resin was compared to structurally similar diglycolamide (DGA) resins containing the extractants N,N,N’,N’-tetraoctyl-diglycolamide (TODGA; DGA, Normal resin) and N,N,N’,N’-tetra(2-ethyl-1-hexyl)-diglycolamide (TEHDGA; DGA, Branched resin). The EXC resins were studied via batch uptake, column elution, extraction capacity, and column stability experiments focusing on potential applications in analytical radiochemistry and nuclear medicine isotope production and purification. The DOODA resin exhibited similar extraction trends to the DGA resins for many metal ions, however, the capacity factors (k’) were reduced, typically following the trend of DGA, normal > DGA, branched > DOODA. The selectivity of DOODA resin towards rare earth elements, trivalent actinides, and some transition metal ions, particularly Cd, Ca, and Ac, is quite different from the existing DGA resins, but follows trends previously identified in solvent extraction experiments. The capacity for extraction of Ca(II) and Eu(III) from nitric acid was higher for the DOODA resin than either DGA resin, while all resins exhibited little extractant loss to the mobile phase over >18,000 bed volumes of elution.