Search Results (953)

Background: Osteoporotic vertebral fractures in the thoracic–lumbar spine are common in older adults and can lead to pain, kyphotic posture, impaired postural control, and altered gait. These changes increase the risk of falls and reduce functional mobility, highlighting the need for effective assessment and intervention strategies. Objectives: To analyze stability and gait in patients who sustained a thoracic–lumbar spinal fracture and underwent minimally invasive surgery. Methods: Seventeen patients participated in this study (women = 11, age 68.36 ± 6.15 years, body weight 68.18 ± 12.8 kg, height 161.45 ± 5.26 cm; men = 6, age 62.67 ± 4.41 years, body weight 78.5 ± 20.36 kg, height 176.67 ± 12.64 cm). All participants had undergone minimally invasive spinal surgery using percutaneous screws reinforced with bone cement 12 months prior. Each patient underwent two assessments: postural stability measurement and biomechanical gait analysis. Statistical analysis was performed using Statistica software (StatSoft, PL), with significance set at p < 0.05. Results: In the stability test, seven participants could not complete the measurement due to falls (FRT = 6.45 ± 2.43), six performed within the normal range (FRT = 2.41 ± 0.9), and four were below the normal range for their age group (FRT = 2.22 ± 1.7). Patients exhibited slower walking speed, shorter stride length, and reduced hip extension during the stance phase (approximately 5° less) due to a forward-leaning posture and cautious gait. Foot placement was flat rather than heel-first, likely as a compensatory strategy to enhance safety. Conclusions: Patients after osteoporotic thoracic–lumbar vertebral fractures treated with minimally invasive surgery demonstrate shorter, wider, and slower steps, along with reduced postural stability, indicating a persistent risk of forward falls. Full article

Gel treatments have been widely applied to control water production in oil and gas reservoirs. However, for water shutoff in dense gas reservoirs, most gel-based treatments focus on individual wells rather than the entire reservoir, exhibiting limited treatment depth, poor durability, and inadequate repeatability Notably, formation damage is a primary consideration in treatment design—most dense gas reservoirs have a permeability of less than 1 mD, making them highly susceptible to damage by formation water, let alone viscous polymer gels. Constrained by well completion methods, gelant can only be bullheaded into deep gas wells in most scenarios. Due to the poor gas/water selective plugging capability of conventional gels, the injected gelant tends to enter both gas and water zones, simultaneously plugging fluid flow in both. Although several techniques have been developed to re-establish gas flow paths post-treatment, treating gas-producing zones remains risky when no effective barrier exists between water and gas strata. Additionally, most water/gas selective plugging materials lack sufficient thermal stability under high-temperature and high-salinity (HTHS) gas reservoir conditions, and their injectivity and field feasibility still require further optimization. To address these challenges, treatment design should be optimized using non-selective gel materials, shifting the focus from directly preventing formation water invasion into individual wells to mitigating or slowing water invasion across the entire gas reservoir. This approach can be achieved by placing large-volume gels along major water flow paths via fully watered-out wells located at structurally lower positions. Furthermore, the drainage capacity of these wells can be preserved by displacing the gel slug to the far-wellbore region, thereby dissipating water-driven energy. This study evaluates the viability of placing gels in fully watered-out wells at structurally lower positions in an edge-water drive gas reservoir to slow water invasion into structurally higher production wells interconnected via numerous microfractures and high-permeability streaks. The gel system primarily comprises polyethyleneimine (PEI), a terpolymer, and nanofibers. Key properties of the gel system are as follows: Static gelation time: 6 h; Elastic modulus of fully crosslinked gel: 8.6 Pa; Thermal stability: Stable in formation water at 130 °C for over 3 months; Injectivity: Easily placed in a 219 mD rock matrix with an injection pressure gradient of 0.8 MPa/m at an injection rate of 1 mL/min; and Plugging performance: Excellent sealing effect on microfractures, with a water breakthrough pressure gradient of 2.25 MPa/m in 0.1 mm fractures. During field implementation, cyclic gelant injections combined with over-displacement techniques were employed to push the gel slug deep into the reservoir while maintaining well drainage capacity. The total volumes of injected fluid and gelant were 2865 m³ and 1400 m³, respectively. Production data and tracer test results from adjacent wells confirmed that the water invasion rate was successfully reduced from 59 m/d to 35 m/d. The pilot test results validate that placing gels in fully watered-out wells at structurally lower positions is a viable strategy to protect the production of gas wells at structurally higher positions. Full article

The WieZhou12 oilfield (also known as WZ12 oilfield, the same below) is in urgent need of development using large-scale volumetric fracturing technology since it is a typical complex fault-block oilfield with low porosity, low permeability, and no natural production capacity. To study the fracturing measures with surfactants in offshore oilfields like WZ12, the surfactant fracturing fluid types were experimentally selected based on their effect of decreasing interfacial tension and enhancing matrix wettability. The water cut law and oil displacement efficiency in displacement experiments were also analyzed, according to surfactant type and fluid characteristics. Next, using the numerical simulation software CMG, the study completed the integrated simulation of volumetric fracturing in the “injection–soaking–flowback” process. Finally, some critical parameters were optimized for the block model, including the quantity of injected fluids, the soaking time, and the rate of fluid flowback. The results showed that the most suitable surfactant was 0.5% ammonium lauryl polyether sulfate (ALES), which had a low interfacial tension of 1.7 × 10⁻² mN/m, a contact angle of 20.071° with the core, and a 52% oil displacement efficiency. From the simulations, the suggested production parameters for energy storage fracturing are as follows: a daily injection volume of 600 m³/d, a soaking time of 25 days post fracturing, and a fluid production rate of 270 m³/d. The findings of this study establish a significant theoretical foundation for optimizing surfactant type and provide construction advice for the integrated measure of fracturing, well shut-in, and production in offshore oilfields. Full article

Background: Bone fracture is a partial or complete break in the continuity of a bone, which poses a significant healthcare burden. It is important to discover a novel method to stimulate and speed-up the healing of bone fractures. Aim: This study aimed to investigate the effects and mechanisms of alternating current (AC) in promoting bone fracture healing. Methods: A rabbit bone fracture model was used. X-ray and Micro-CT evaluated fracture healing, while HE staining and immunohistochemistry assessed morphological changes. In vitro, pre-osteoblastic cells were tested with alizarin red S staining and alkaline phosphatase (ALP) activity. RNA-seq analysis explored potential mechanisms. Results: X-ray evaluation showed that alternating current stimulation (ACS) promoted bone formation and shaping by day 14 post-treatment. Micro-CT results revealed significant new bone formation as early as day 3 and day 7 (p < 0.05). HE staining indicated more trabecular bone formation in the ACS group compared to the model group at days 7 and 14. Immunohistochemistry showed higher expression of BMP-2 and VEGF in the ACS group by day 7. In vitro, ACS enhanced osteogenic differentiation, increasing calcified nodule formation and ALP activity. Gene expression analysis demonstrated significant changes in key osteogenic genes, confirmed by multiple immunohistochemical staining. Conclusions: ACS may be a novel method for treating bone fractures more rapidly, significantly relieving the patient’s burden, particularly in the early stages of bone healing. Full article

Biocomposites based on natural fibres represent a promising solution for the circular economy. The aim of this study was to develop and characterise a biodegradable composite based on sheep wool from herds raised in the Kyrgyz Republic and polylactide (PLA 4032D). Composite samples with a wool–PLA ratio of 50:50 were fabricated by thermoforming at a temperature of 168 °C for 30 s (n = 10). Mechanical properties tests were performed (PN-EN ISO 604—compression tests), for impact resistance (Charpy method), differential scanning calorimetry (DSC), and measurements of density and thermal conductivity. Biodegradation samples were subjected to enriched soil conditions for 6 weeks in two variants (with and without irrigation). The results showed that the addition of sheep wool to the PLA matrix significantly increased compressive strength (23.56 ± 5.23 MPa) and impact energy absorption (226.2 ± 23.8 kJ/m²) compared to neat PLA. After biodegradation, a 59% reduction in compressive strength was observed while maintaining an increase in fracture energy, suggesting a change in the failure mechanism. The density (0.27 ± 0.02 g/cm³) and the thermal conductivity (0.127 W/m·K) comparable to polymer foams indicate potential for thermal insulation applications. Microscopy and DSC analysis confirmed complete biodegradation under soil conditions. The developed biocomposite from Kyrgyz sheep wool demonstrates the potential for valorisation of local fibrous waste for biodegradable materials with functional insulation properties. Full article

This study resolves the challenge of balancing curing speed and performance in room-temperature-curing epoxy coatings by developing a novel system grafted with hexamethylene diisocyanate trimer (HDI trimer) and polyethylene glycol 200 (PEG200). Employing DMP-30 as the catalyst, the coating achieves efficient curing at 25 °C, with complete cure within 7.5 h. The cured material exhibits outstanding thermal stability (T₅₀% = 380.83 °C) and mechanical properties. Fracture morphology analysis reveals a uniform ductile structure, confirming its high toughness and durability. Furthermore, kinetic models accurately predict curing behavior across different temperature curves, providing crucial guidance for optimizing industrial coating processes. This research offers a viable strategy for designing high-performance, rapid curing epoxy materials, demonstrating significant application potential in coating systems, composite surfaces, and electronic encapsulation. Full article

Distributed acoustic sensing (DAS) technology is gaining popularity for real-time monitoring during the hydraulic fracturing of unconventional reservoirs. By transforming a standard optical fiber into a dense array of acoustic sensors, DAS provides continuous spatiotemporal measurements along the entire wellbore. Although accurate DAS-based real-time diagnosis of multistage hydraulic fracturing is critical for optimizing the efficiency of stimulation operations and mitigating operational risks in horizontal tight oil wells, existing methods often fail to provide integrated qualitative and quantitative insights. To address this gap, we present an original diagnostic workflow that synergistically combines frequency band energy (FBE), low-frequency DAS (LF-DAS), and surface injection data for simultaneous fluid/proppant allocation and key downhole anomaly identification. Field application of the proposed framework in a 47-stage well demonstrates that FBE (50–200 Hz) enables robust cluster-level volume estimation, while LF-DAS (<0.5 Hz) reveals fiber strain signatures indicative of mechanical integrity threats. The workflow can successfully diagnose sand screenout, diversion, out-of-zone flow, and early fiber failure—events often missed by conventional monitoring. By linking distinct acoustic fingerprints to specific physical processes, our approach transforms raw DAS data into actionable operational intelligence. This study provides a reproducible, field-validated framework that enhances understanding in the context of fracture treatment, supports real-time decision making, and paves the way for automated DAS interpretation in complex completions. Full article

Background/Objectives: Osteoporosis represents a major yet underdiagnosed public health concern in developing countries, including Tunisia. Limited awareness, delayed diagnosis, and suboptimal adoption of preventive strategies contribute to increased risk of fragility fractures in aging populations. This study aimed to assess post-pandemic knowledge, attitudes, and preventive practices regarding osteoporosis in the Tunisian general population. Methods: A cross-sectional survey was conducted between February and April 2024 in six randomly selected community pharmacies in Tunis. Adults ≥ 40 years old completed a validated 31-item questionnaire assessing socio-demographic factors, osteoporosis knowledge, risk factors, screening practices, and preventive behaviors. A total of 160 fully completed questionnaires were analyzed using SPSS v22. Results: Only 60.6% of respondents reported awareness of osteoporosis. Knowledge levels were significantly higher in men (8.37 vs. 7.40; p = 0.043), urban residents (8.22 vs. 7.21; p = 0.036), participants with higher education (8.73 vs. 7.00; p < 0.001), those with a family history (8.58 vs. 7.49; p = 0.033), and individuals already diagnosed (9.19 vs. 7.63; p = 0.025). Screening rates were low: only 11.3% had ever undergone DXA testing, despite 18.8% reporting prior fractures. Preventive behaviors were inadequate: 80% did not supplement calcium, 88.1% did not use vitamin D, and 58.8% did not engage in <30 min of daily activity. Osteoporosis was reported by 13.1% of participants and 95.2% of diagnosed cases received treatment, predominantly bisphosphonates (75%). Comorbidities were significantly associated with osteoporosis (24.5% vs. 7.5%; p = 0.003). Conclusions: This study reveals suboptimal awareness, limited access to screening, and insufficient preventive behaviors regarding osteoporosis in Tunisia. Targeted educational initiatives, expansion of DXA availability, adoption of national osteoporosis guidelines, and multidisciplinary stakeholder involvement are critical to improve early detection, prevention, and management in the aging Tunisian population. Furthermore, promoting balanced nutrition that includes calcium- and vitamin D-rich foods, along with appropriate dietary supplementation when needed, is an essential preventive strategy to support optimal bone health and reduce osteoporosis risk in the general population. Full article

Addressing the issues of low permeability, stress sensitivity in CBM reservoirs, and severe reservoir damage from traditional fracturing fluids, we prepared a Gemini surfactant (designated GEM-CBM) for CBM development using ethanolamine, epichlorohydrin, and alkylamidopropyl dimethylamine as feedstocks. On this basis, we further developed a clean fracturing fluid system. The synthesis process of GEM-CBM was optimized via single-factor and orthogonal experiments. The surface activity of GEM-CBM was assessed through surface tension measurements, whereas the sand-carrying capacity, the rheological properties, gel-breaking performance, and reservoir compatibility were comprehensively examined. The optimal conditions for GEM-CBM are listed as follows: the molar ratio of intermediate to alkylamidopropyl dimethylamine being 1:2.2, reacted at 80 °C for 20 h, with a conversion rate of 96.5%. FTIR verified the existence of characteristic functional groups, and EA results matched the theoretical molecular composition. GEM-CBM has good performance, with a critical micelle concentration (CMC) of 19.0 μmol/L and a surface tension at CMC (γCMC) of 37.44 mN/m. The optimized clean fracturing fluid (formulation: 2.3% GEM-CBM + 0.3% Tween-80 + simulated formation water with 150,000 mg/L mineralization) exhibited a viscosity of 82 mPa·s (66.7% viscosity retention rate) after being subjected to 100 min of shearing at 90 °C and 170 s⁻¹. At 90 °C, the proppant settlement velocity was less than 0.15 mm/s, and complete gel breaking was achieved within 30 min without residues. For coal cores from the Qinshui Basin, the permeability recovery rate reached 78.6%. The permeability recovery rate of coal cores from the Qinshui Basin reached 78.6%. This fracturing fluid realizes viscosity enhancement and sand carrying via the worm-like micellar network formed by GEM-CBM, inducing minimal damage to CBM reservoirs and offering technical support for efficient CBM extraction. Full article

Dentigerous cysts (DCs), usually linked to unerupted teeth, are the second most common odontogenic cysts. However, synchronous DCs are rarely seen in children without syndromic conditions. This study reports two cases of male children with no systemic illnesses who showed multiple cystic lesions in the jaw. Conventional treatment typically involves enucleation and tooth extraction, which can lead to significant complications, including infection, nerve damage that may cause temporary or permanent numbness, damage to nearby teeth, and, in cases of large cysts, jaw fractures—potentially impacting the child’s quality of life. A conservative decompression method was used, employing custom-made tubes to keep communication between the cystic and oral cavities, thereby lowering intracystic pressure. This approach resulted in complete healing of the lesions and successful eruption of permanent teeth, while safeguarding vital anatomical structures and avoiding more invasive surgery, with an uneventful clinical course. Additionally, 3-year postoperative orthopantomograms are presented, showing complete resolution of the lesions with no recurrence. These results demonstrate the effectiveness of decompression in treating multiple dentigerous cysts in pediatric patients, highlighting its advantages in preserving oral function and aesthetics while reducing surgical risks. Full article

An Incomplete Atypical femoral fracture is subtle and requires early diagnosis. However, artificial intelligence models for these fractures often fail in real-world clinical settings due to the “domain shift” problem, where performance degrades when applied to new data sources. This study proposes a data-centric approach to overcome this problem. We introduce an anatomy-based four-step preprocessing pipeline to normalize femoral X-ray images. This pipeline consists of (1) semantic segmentation of the femur, (2) skeletonization and centroid extraction using RANSAC, (3) rotational alignment to the vertical direction, and (4) cropping a normalized region of interest (ROI). We evaluate the effectiveness of this pipeline across various one-stage (YOLO) and two-stage (Faster R-CNN) object detection models. On the source domain data, the proposed alignment pipeline significantly improves the performance of the YOLO model, with YOLOv10n achieving the best performance of 0.6472 at mAP@50–95. More importantly, in zero-shot evaluation on a completely new domain, standing AP X-ray, the model trained on aligned data exhibited strong generalization performance, while the existing models completely failed (mAP = 0), YOLOv10s, which applied the proposed method, achieved 0.4616 at mAP@50–95. The first-stage detector showed more consistent performance gains from the alignment technique than the second-stage detector. Normalizing medical images based on inherent anatomical consistency is a highly effective and efficient strategy for achieving domain generalization. This data-driven paradigm, which simplifies the input to AI, can create clinically applicable, robust models without increasing the complexity of the model architecture. Full article

Distributed Acoustic Sensing (DAS) technology has emerged as a valuable tool for monitoring fluid and proppant injection during hydraulic fracturing. One of its applications involves estimating cluster-level fluid and proppant allocations in real time. However, significant uncertainties remain in the quantitative calculation of injected volumes due to limitations in frequency band energy (FBE) data extraction, cluster depth determination, and volume estimation algorithms. This study presents an enhanced workflow for quantitatively estimating fluid and proppant allocations from DAS-derived FBE data while minimizing uncertainties. The workflow integrates multi-band and summed-energy analyses with the optimized selection of calculation algorithms to reduce interpretation uncertainties. The results show that FBE [50–200 Hz] exhibits the highest sensitivity to injection activities, local minima on summed FBE can accurately pinpoint top and bottom depths of each cluster, and a power-law model linking acoustic energy to flow rate allows for quantitative calculation. Field applications demonstrate consistent improvements in fluid and proppant volume estimation accuracy. Validation against post-frac numerical simulations shows that estimated fluid and proppant allocations agree within a 6% error, confirming the method’s quantitative reliability. By addressing key sources of uncertainty, this approach enhances DAS-based fracture diagnostics and provides actionable guidance for real-time decision making in unconventional completions. Full article

Among the various completion strategies used in multi-stage hydraulic fracturing of horizontal wells, the limited entry design has become one of the most common approaches to promote more uniform slurry distribution. This method involves reducing the number of perforations so that higher perforation friction is generated at each entry point. The increased pressure drops force fluid and proppant to be diverted across multiple clusters rather than concentrating at only a few, thereby enhancing stimulation efficiency along the lateral. In this study, Computational Fluid Dynamics (CFD) simulations were performed to investigate how perforation erosion influences acoustic signals measured by Distributed Acoustic Sensing (DAS). Unlike previous studies that assumed perfectly circular perforations, this work uses oval-shaped geometries to better reflect the irregular erosion observed in the field, which provides more realistic modeling. The workflow involved building wellbore and perforation geometries, generating computational meshes, and solving transient turbulent flow using Large Eddy Simulation (LES) coupled with the Ffowcs Williams–Hawkings (FW-H) acoustic model. Acoustic pressure was then estimated at receiver points and converted into sound pressure level for analysis. The results show that, for a given perforation size, changes in flow rate cause log(q) versus sound pressure level to follow a straight line defined by a constant slope and varying intercept. Even when erosion alters the perforation into an oval shape, the intercept increases logarithmically, resulting in reduced sound amplitude, while the slope remains unchanged. Furthermore, when the cross-sectional area and flow rate are equal, oval perforations produce higher sound amplitudes than circular ones, suggesting that perforation geometry has a measurable influence on the DAS signal. This indicates that even when the same amplitude DAS signal is obtained, assuming circular perforations when estimating the fluid distribution leads to an overestimation if the actual perforation shape is oval. These findings highlight the importance of considering irregular erosion patterns when linking DAS responses to fluid distribution during hydraulic fracturing. Full article

The development of unconventional resources continues to be propelled by innovations that enhance economic efficiency and maximize reservoir contact within operational constraints. Among the most recent of these is the U-shaped, or “horseshoe,” well design, which connects two parallel horizontal laterals with a 180° turn, effectively doubling the reservoir exposure from a single wellhead. This paper provides a comprehensive literature review of the current state of knowledge on U-shaped well technology. It surveys the operational drivers for their adoption, the critical drilling, and completion technologies that have enabled its successful implementation and discusses key design considerations for a successful operation. Field data from major North American shale basins, including the Permian, Eagle Ford, Bakken, and Haynesville, demonstrate substantial economic benefits, such as capital cost savings of approximately 20–25% compared to traditional methods. Lifecycle assessments indicate notable environmental advantages, including a 29.3% reduction in carbon emissions, a 15.8% reduction in water use, and a 50% decrease in land disturbance. Despite these clear benefits, gaps remain regarding long-term performance validation, stimulation of curved sections, and fracture modeling accuracy. Addressing these gaps is essential to fully realize the potential of U-shaped wells as a sustainable and economically attractive approach in the evolving landscape of unconventional energy development. Full article

Severe bone loss from trauma, fractures, tumor resections, and disease are devastating injuries that do not heal completely without external, and most of the time surgical, interventions. Although surgical interventions such as bone grafts and metal prostheses are commonly employed, these conventional approaches present several limitations, including limited donors, risks of immune rejection and postoperative inflammation, and significant pain experienced by both donors and recipients. Hydrogels offer a promising alternative because of their controllable mechanical properties, biocompatibility, and structural resemblance to the extracellular matrix. In addition, hydrogels can be modified with substances such as growth factors, hormones, and drugs to facilitate accelerated bone repair. This review summarizes the recent advances in hydrogel development for bone repair, their structural design, biological functionality, and preclinical and clinical applications. Full article