Search Results (324)

Introduction: Canine sinonasal aspergillosis (SNA) can present singular as a primary disease or secondary to concurrent sinonasal pathology. We hypothesized that treatment response and prognosis differ between both forms, particularly when sinusitis is present. Methods: In this retrospective study, 30 dogs with SNA were categorized as either group pA (primary aspergillosis) or group sA (secondary aspergillosis; with additional sinonasal pathology). History, diagnostics, endoscopic therapeutic intervention of affected nose and sinus, and follow-up data were analyzed. Results: Group pA included 19/30 dogs (63%), with 15 dogs (79%) showing concurrent sinusitis. Group sA included 11/30 dogs (37%; additional conditions: foreign bodies, dental pathologies, frontal bone fracture). Only 2/11 sA dogs (18%) had sinusitis. Follow-ups in group pA were more frequent than in group sA (p = 0.04). Need for re-treatments differed significantly between groups (p = 0.02) and in dogs with sinusitis, regardless of group (p < 0.001). In group sA, treating the underlying condition plus single endoscopic debridement ± antifungal therapy led to clinical resolution in 11 of 12 dogs (92%). Conclusions: Primary SNA is frequently associated with sinusitis, requires aggressive repeated antifungal therapy, and may not achieve a definitive cure. Secondary SNA is usually confined to the nasal cavity, responds well to underlying condition treatment, carries better prognosis, and requires fewer antifungal treatments. Full article

Polylactic acid (PLA) is an eco-friendly polymer known for its biodegradability and biocompatibility, yet its properties are sensitive to recycling and sterilization. These processes may cause chain scission and structural irregularities, leading to reduced strength, brittleness, or unpredictable deformation. In this study, PLA and recycled PLA (Re-PLA) specimens were produced by FDM 3D printing with different infill rates (25%, 50%, 75%), layer thicknesses (0.15, 0.20, 0.25 mm), and printing orientations (0°, 45°, 90°). Steam sterilization at 121 °C and 1 bar for 15 min simulated biomedical conditions. Mechanical, surface, degradation, and biocompatibility properties were examined using three-point bending, roughness measurements, SEM, and cell viability tests. Results showed that infill rate was the main parameter affecting flexural strength and surface quality, while orientation increased roughness. Sterilization and recycling made deformation less predictable, particularly in St-Re-PLA. SEM revealed stronger bonding at higher infill, but more brittle fractures in PLA and Re-PLA, while sterilized specimens showed ductile features. No visible degradation occurred at any infill level. Regression analysis confirmed that second-order polynomial models effectively predicted flexural strength, with layer thickness being most influential. These findings provide critical insights into optimizing PLA and Re-PLA processing for biomedical applications, particularly in the production of sterilizable and recyclable implantable devices. Full article

Plasma arcs generated by lightning strikes are prone to tripping distribution lines, especially 10 kV lines. To reduce the lightning-induced tripping rate of 10 kV distribution lines and ensure the safe operation of power systems, this paper proposes a same-level double-fracture lightning protection device containing the electronegative gas trifluoroiodomethane (CF₃I). A mathematical model of the gas arc-extinguishing process is established based on magnetohydrodynamics. Meanwhile, the mechanism of CF₃I in the arc-extinguishing process is analyzed according to its physical and chemical properties, and the arc-extinguishing process is simulated using COMSOL Multiphysics 6.0. The results show that (1) the arc-extinguishing effect is optimal when the horizontal distance of the compression pipeline of the device is 9 mm; (2) under the action of power frequency currents with different initial phases of π/2 and 0, the arc-extinguishing device can extinguish the arc within 800 $\mathsf{\mu }\mathrm{s}$ without re-ignition; and (3) in the arc-extinguishing process involving CF₃I, the arc can be extinguished within 710 $\mathsf{\mu }\mathrm{s}$, which is 11.2% quicker than that without CF₃I. Meanwhile, CF₃I can effectively reduce the arc temperature at the initial stage of arc extinguishing, avoiding damage caused by excessive internal compression of the device. Full article

Hydraulic fracturing is a critical technical means for enhancing production in gas fields, and post-fracturing flow-back constitutes a crucial phase of fracturing operations. Proppant backflow during the flow-back process significantly impacts both the effectiveness of stimulation and subsequent production. Particularly for tight gas reservoirs, achieving rapid post-fracturing flow-back while preventing proppant re-flux is essential. To date, domestic and international scholars have conducted extensive research on proppant backflow during flow-back operations, with laboratory experimental studies serving as a vital investigative approach. However, due to limitations in experimental apparatuses, further investigation is required regarding the migration mechanisms of proppants during flow-back, proppant backflow prevention techniques, and associated operational parameters. This paper developed a novel visualized flow chamber capable of simulating proppant migration in vertical fractures under closure stress conditions. Extensive proppant backflow experiments conducted using this device revealed that (1) proppant backflow initiates at weak structural zones near the two-phase interface boundaries; (2) proppant backflow occurs in three distinct stages, with varying fluid erosive capacities on proppant particles at each phase; (3) a multi-stage fiber injection sand control process was optimized; (4) at low proppant concentrations (<10 kg/m²), the fiber concentration should be 0.8%; at high proppant concentrations (>10 kg/m²), the fiber concentration should be 1.2%. The recommended fiber length is 6 mm. Full article

Background and Clinical Significance: Retained intrarenal foreign bodies are rare adverse events after endourological stone surgery. Guidewire fracture or detachment is uncommon and can trigger infection, obstruction, or encrustation if unrecognized. We report antegrade percutaneous snare retrieval of a retained hydrophilic guidewire tip and provide a concise literature review (seven PubMed-indexed intrarenal cases identified by a structured search) to inform diagnosis, management, and prevention. We also clarify the clinical rationale for an antegrade versus retrograde approach and the sequencing of decompression, definitive stone management, and stenting in the context of sepsis. Case Presentation: A 75-year-old woman with diabetes presented with obstructive left pyelonephritis from ureteral and renal calculi. After urgent percutaneous nephrostomy, she underwent semirigid and flexible ureteroscopic lithotripsy with double-J stenting; the nephrostomy remained. During routine tube removal, the stent was inadvertently extracted. Seven days later she re-presented with fever and flank pain. KUB and non-contrast CT showed a linear 4 cm radiopaque foreign body in the left renal pelvis with dilatation. Under local anesthesia and fluoroscopy, a percutaneous tract was used to deploy a 35 mm gooseneck snare and retrieve the distal tip of a hydrophilic guidewire (Sensor/ZIP-type). Inflammatory markers were normalized; the nephrostomy was removed on day 5; six-week imaging confirmed complete clearance without complications. Conclusions: Retained guidewire fragments should be suspected in postoperative patients with unexplained urinary symptoms or infection. Cross-sectional imaging confirms the diagnosis, while minimally invasive extraction—preferably an antegrade percutaneous approach for rigid or coiled fragments—achieves prompt resolution. This case adds to the seven prior PubMed-indexed intrarenal reports identified in our review, bringing the total to eight, underscoring prevention through pre-/post-use instrument checks, immediate fluoroscopy when withdrawal resistance occurs, and structured device accounting to avoid “never events.” Full article

Background: Mandibular fractures are often treated with open reduction and internal fixation in order to restore function and anatomy. This study analyzes postoperative complications and outcomes over one year at a high-volume teaching hospital, focusing on fracture types, treatment methods, and the impact of providers’ experience. Methods: This retrospective study included patients 12 years of age or older with mandibular fractures resulting from trauma during a 1-year period, January–December 2022 in a level 1 trauma center. Medical records were reviewed, and patient data was collected. Patients were categorized into 3 groups: Group 1 (surgical treatment), Group 2 (closed treatment, i.e., dental splints, arch bars/eyelets), and Group 3 (observation/soft diet). The results were tabulated, and standard descriptive statistics were used. Results: 141 patients with 223 mandibular fractures met inclusion criteria. Throughout all groups, 18 surgically treated patients (12.7%) and one patient treated with arch bars (0.07%) required additional unintended surgical procedure such as plate removal with/without re-plating, or orthognathic surgery for occlusal correction. Conclusions: The complication rates in this cohort align with the existing literature, though variations may origin from limited sample size, short follow-up and patient comorbidities. The involvement of less experienced surgeons during on-call hours most likely contributed to outcome variability. Despite challenges, most patients had favorable outcomes. Full article

Background: NVD003 is an autologous, adipose tissue-derived stem cell-based tissue-engineered bone graft substitute with pro-osteogenic, anti-resorptive, and pro-angiogenic properties. Here, we describe highlights from the NVD003 preclinical development program as well as early clinical experience. Methods: NVD003 is produced in a Good Manufacturing Practice-controlled process from adipose stem cells collected during a minimally invasive liposuction procedure. The final implant is a ready-to-use moldable putty with fixed mineral content and predefined physiologic ranges of osteogenic cells and bioactive growth factors. Preclinical pharmacology studies were conducted in nude rats using a paravertebral implantation model, and subsequently, in a femoral critical-sized bone defect (CSBD) model. In a first-in-human Phase 1b/2a study, NVD003 was used for fracture osteosynthesis with classical fixation material in nine adults with recalcitrant lower limb non-union. NVD003 was also used at the discretion of treating physicians in four pediatric patients surgically treated for congenital pseudarthrosis of the tibia (CPT) with the Masquelet technique. Efficacy was evaluated as clinical healing and in terms of bone formation, bone union, and bone remodeling on radiographs and computed tomography using the extended Lane and Sandhu Scale. Results: Preclinical studies indicated that NVD003 requires cellularity for its bioactivity and moreover facilitates bone union when used as a graft material in femoral CSBD. In the clinical study, nine adult participants were successfully grafted with NVD003 and completed study follow-up to 24 months, with extended safety follow-up to 5 years ongoing. No adverse events were considered related to NVD003. Maximal bone formation occurred between 3 and 12 months post-implantation; the mean time to clinical healing was 6 months and the mean time to radiological union was 17 months. Ultimately, 89% (8/9) of patients achieved bone union without refracture. All four pediatric patients with CPT also achieved lasting bone union following grafting with NVD003. No safety signals were observed over a mean follow-up of 62.1 months. Conclusions: NVD003 represents a safe, autologous bone graft substitute product without side effects of heterotopic ossification or bone resorption. NVD003 facilitated bone union in adult and pediatric patients even under severe pathophysiological conditions. Full article

Electrical resistivity tomography (ERT) is one of the most commonly used geophysical methods for imaging the distribution of electrical resistivity in the subsurface. It is often employed to characterise heterogeneity in karst regions and locate cavities and conduits below the surface. The resistivity contrast between the host rock and the cavity depends on the material filling the cavity. Air has a high electrical resistivity and should therefore produce strong reflections and refractions off cavity walls. However, cavities are not always easily detectable. A decrease in resistivity contrast at the interface between rock and air may result from different physical conditions relating to pore saturation, fracturing and stress near the cavity walls. Our first goal is to understand how extensive fracturing and hydrogeological conditions in the first subsurface layers can affect electric current flow in the presence of a karst tunnel. We use the commercial Res2Dmod software 3.0 to simulate an ERT on several ground models. The results, which are based on hydrogeological models, are presented for several conditions of a karst conduit: empty; full of water within a homogeneous background; and below the groundwater level in the presence of extensive fractures in the shallow layer above it. Full article

Background and Objectives: Adolescent diaphyseal clavicle fracture surgery has increased in recent years. However, the optimal operative method remains debated, particularly between elastic stable intramedullary nailing (ESIN) and plate fixation. This study compared postoperative outcomes and complication rates between ESIN and plate fixation for treating diaphyseal clavicle fractures in adolescent patients. Materials and Methods: We conducted a retrospective review of 35 adolescents who underwent surgery for diaphyseal clavicle fractures between 2010 and 2024. Patients were assigned to either the ESIN group (n = 18) or the plate fixation group (n = 17). Postoperative outcomes assessed included the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, intraoperative time, time to complete fracture union, and clavicle shortening at 1 year postoperatively. Postoperative complications were also evaluated. Results: Fracture union occurred significantly faster with ESIN than with plate fixation, specifically 3 weeks earlier (11.0 weeks vs. 14.0 weeks; p < 0.001). No significant differences were observed between the groups in QuickDASH scores, intraoperative time, or clavicle shortening at 1 year. The overall postoperative complication rate was 25.7% (9/35), with no statistically significant difference between the ESIN (27.8%) and plate fixation groups (23.5%) (p = 0.774). Refractures occurred exclusively in the plate fixation group (n = 2), while one patient in the ESIN group required early nail removal due to insertion site irritation. Conclusions: ESIN provided functional and radiographic outcomes comparable to plate fixation in adolescents with diaphyseal clavicle fractures, with a 3-week shorter time to union and a less-invasive surgical approach. Full article

Different polyurethanes (PURs) and silicone for potential use in particle accelerators and detectors have been characterized in the uncured state, after curing, and after exposure to ionizing irradiation in ambient air and in liquid helium. The viscosity evolution during processing was measured with a rheometer. Dynamic mechanical analysis (DMA) and Shore A hardness measurements were applied to detect irradiation-induced crosslinking and chain scission effects. Uniaxial tensile and flexural tests under ambient and cryogenic conditions have been performed to assess changes in mechanical strength, elongation at break, and elastic properties. The initial viscosity of 550 cP at 25 °C of the uncured PUR RE700-4 polyol and RE106 isocyanate system for protective encapsulation is sufficiently low for impregnation of small magnet coils, but the pot life of about 30 min is too short for impregnation of large magnet coils. The cured RE700-4 system has outstanding mechanical properties at 77 K (flexural strength, impact strength, and fracture toughness). When RE700-4 is exposed to ionizing radiation, chain scission and cross-linking occur at a similar rate. In the other casting systems, irradiation-induced changes are cross-linking dominated, as manifested by an increase of the rubbery shear modulus (G’_rubbery), the ambient temperature Young’s modulus (E_RT), and the Shore A hardness. Cross-linking rates are strongly reduced when irradiation occurs in liquid helium. The irradiation effect on mechanical properties can be strongly dependent on the testing temperature. The RT mechanical strength and strain at fracture of the cross-linking silicone is drastically decreased after 1.6 MGy, whereas its 77 K strain at fracture has almost doubled. In addition, 77 K elastic moduli are similar for all pure resins and only slightly affected by irradiation. Full article

Structures that possess negative Poisson’s ratio are termed “Auxetic” structures. They elongate laterally on longitudinal–tensile loading and compress laterally on longitudinal–compressive loading. Auxetic structures are a composition of unit cells that are available in various geometries, which include triangular, hexa-triangular, re-entrant, chiral, star, arrowhead, etc. Due to their unique shape, these structures possess remarkably good mechanical properties such as shear resistance, indentation resistance, fracture resistance, synclastic behavior, energy absorption capacity, etc. However, they have poor load-bearing capacity. To improve the load bearing strength of these structures, this paper presents a numerical analysis of oriented re-entrant structured (ORS) beams with auxetic clusters aligned at various angles (0°, 45° and 90°), using Finite Element Methods. Oriented re-entrant unit cell clusters enclosed by a bounded frame were modeled and a three-point bending test was conducted to perform a comparison study on deformation mechanisms of the different oriented re-entrant honeycomb structures with honeycomb beams. The computational analysis of ORS beams revealed that the directional deformation and normal strain along the x-axis were the lowest in ORS45, followed by ORS90, ORS0, and honeycomb. Among all the beams, ORS45 displayed the best load-bearing capacity with comparably low mass density. Full article

Due to post-cementing hydraulic fracturing and other operational stresses, inadequate mechanical properties or suboptimal design of the cement sheath can lead to tensile failure and microcrack development, compromising both hydrocarbon recovery and well integrity. In this study, three field-deployed cement slurry systems were compared on the basis of their basic mechanical properties such as compressive and tensile strength. Laboratory-scale physical simulations of hydraulic fracturing during shale oil production were conducted, using dynamic permeability as a quantitative indicator of integrity loss. The experimental results show that evaluating only basic mechanical properties is insufficient for cement slurry system design. A more comprehensive mechanical assessment is re-quired. Incorporation of an expansive agent into the cement slurry system can alleviate the damage caused by the microannulus to the interfacial sealing performance of the cement sheath, while adding a toughening agent can alleviate the damage caused by tensile cracks to the sealing performance of the cement sheath matrix. Through this research, a microexpansive and toughened cement slurry system, modified with both expansive and toughening agents, was optimized. The expansive agent and toughening agent can significantly enhance the shear strength, the flexural strength, and the interfacial hydraulic isolation strength of cement stone. Moreover, the expansion agents mitigate the detrimental effects of microannulus generation on the interfacial sealing, while the toughening agents alleviate the damage caused by tensile cracking to the bulk sealing performance of the cement sheath matrix. This system has been successfully implemented in over 100 wells in the GL block of Daqing Oilfield. Field application results show that the proportion of high-quality well sections in the horizontal section reached 88.63%, indicating the system’s high performance in enhancing zonal isolation and cementing quality. Full article

Control valves in nuclear systems operate under high-pressure differentials generating intense transient fluid forces that induce destructive structural vibrations, risking resonance and the valve stem fracture. In this study, computational fluid dynamics (CFD) was employed to characterize the internal flow dynamics of the valve, supported by experiment validation of the fluid model. To account for nonlinear structural effects such as contact and damping, a coupled fluid–structure interaction approach incorporating nonlinear perturbation analysis was applied to evaluate the dynamic response of the valve core assembly under fluid excitation. The results indicate that flow separation, re-circulation, and vortex shedding within the throttling region are primary contributors to structural vibrations. A comparative analysis of stability coefficients, modal damping ratios, and logarithmic decrements under different valve openings revealed that the valve core assembly remains relatively stable overall. However, critical stability risks were identified in the lower-order modal frequency range at 50% and 70% openings. Notably, at a 70% opening, the first-order modal frequency of the valve core assembly closely aligns with the frequency of fluid excitation, indicating a potential for critical resonance. This research provides important insights for evaluating and enhancing the vibration stability and operational safety of control valves under complex flow conditions. Full article

In the Kelameili volcanic gas reservoir, primary hydraulic fracturing treatments in some wells take place on a limited scale, resulting in a rapid decline in production post stimulation and necessitating re-fracturing operations. However, prolonged production has led to a significant evolution in the in situ stress field, which complicates the design of re-fracturing parameters. To address this, this study adopts an integrated geology–engineering approach to develop a formation-specific geomechanical model, using rock mechanical test results and well-log inversion to reconstruct the reservoir’s initial stress field. The dynamic stress field simulations and re-fracturing parameter optimization were performed for Block Dixi-14. The results show that stress superposition effects induced by multiple fracturing stages and injection–production cycles have significantly altered the current in situ stress distribution. For Well K6, the optimized re-fracturing parameters comprised a pump rate of 12 m³/min, total fluid volume of 1200 m³, prepad fluid ratio of 50–60%, and proppant volume of 75 m³, and the daily gas production increased by 56% correspondingly, demonstrating the effectiveness of the optimized re-fracturing design. This study not only provides a more realistic simulation framework for fracturing volcanic rock gas reservoirs but also offers a scientific basis for fracture design optimization and enhanced gas recovery. The geology–engineering integrated methodology enables the accurate prediction and assessment of dynamic stress field evolution during fracturing, thereby guiding field operations. Full article

This work systematically investigates the Zn-content-dependent phase evolution (1–12 at.%) and its correlation with mechanical properties in as-cast Mg–2Y–xZn alloys. A sequential phase transformation is observed with the Zn content increasing: the microstructure evolves from X-phase dominance (1–2 at.% Zn) through W-phase formation (3–6 at.% Zn) to I-phase emergence (12 at.% Zn). Optimal mechanical performance is attained in the 2 at.% Zn-containing alloy, with measured tensile properties reaching 239 MPa UTS and 130 MPa YS, while maintaining an elongation of 12.62% prior to its gradual decline at higher Zn concentrations. Crystallographic analysis shows that the most significant strengthening effect of the X-phase originates from its coherent orientation relationship with the α-Mg matrix and the development of deformation-induced kink bands. Meanwhile, fine W-phase particles embedded within the X-phase further enhance alloy performance by suppressing X-phase deformation, revealing pronounced synergistic strengthening between the two phases. Notably, although both the I-phase and W-phase act as crack initiation sites during deformation, their coexistence triggers a competitive fracture mechanism: the I-phase preferentially fractures to preserve the structural integrity of the W-phase, effectively mitigating crack propagation. These dynamic interactions of second phases during plastic deformation—synergistic strengthening and competitive fracture—provide a novel strategy and insights for designing high-performance Mg–RE–Zn alloys. Full article