Extrusion Rate Research Articles

Operative techniques and materials in ossiculoplasty

Successful ossiculoplasty aims to improve conductive hearing loss by restoring the mechanical transmission of energy from the tympanic membrane to the oval window. Ossiculoplasty is typically performed under general anesthesia with facial nerve monitoring as standard practice in our institution. Titanium implants have become the mainstay choice of prosthesis, due to its low density, high durability, and lower extrusion rate compared to other alloplastic implants. While microscopic techniques for ossiculoplasty have been the traditional approach, endoscopic ossiculoplasty has risen in popularity due to improved visualization of the middle ear.

Treatment of Microsporidium Nosema bombycis Spores with the New Antiseptic M250 Helps to Avoid Bacterial and Fungal Contamination of Infected Cultures without Affecting Parasite Polar Tube Extrusion.

Microsporidia are a group of widespread eukaryotic spore-forming intracellular parasites of great economic and scientific importance. Since microsporidia cannot be cultured outside of a host cell, the search for new antimicrosporidian drugs requires an effective antiseptic to sterilize microsporidian spores to infect cell lines. Here, we show that a new polyhexamethylene guanidine derivative M250, which is active against fungi and bacteria at a concentration of 0.5-1 mg/L, is more than 1000 times less effective against spores of the microsporidium Nosema bombycis, a highly virulent pathogen of the silkworm Bombyx mori (LC50 is 0.173%). Treatment of N. bombycis spores that were isolated non-sterilely from silkworm caterpillars with 0.1% M250 solution does not reduce the rate of spore polar tube extrusion. However, it completely prevents contamination of the Sf-900 III cell culture medium by microorganisms in the presence of antibiotics. The addition of untreated spores to the medium results in contamination, whether antibiotics are present or not. Since 0.1% M250 does not affect spore discharging, this compound may be promising for preventing bacterial and fungal contamination of microsporidia-infected cell cultures.

Mogroside V alleviates the heat stress-induced disruption of the porcine oocyte in vitro maturation

Heat stress (HS) is a stressor that negatively affect female reproduction. Specially, oocytes are very sensitive to HS. It has been demonstrated that some active compounds can protect oocyte from HS. We previously found that Mogroside V (MV), extracted from Siraitia grosvenorii (Luo Han Guo), can protect oocyte from many kinds of stresses. However, how MV alleviates HS-induced disruption of oocyte maturation remains unknown. In this study, we treated the HS-induced porcine oocytes with MV to examine their maturation and quality. Our findings demonstrate that MV can effectively alleviate HS-induced porcine oocyte abnormal cumulus cell expansion, decrease of first polar body extrusion rate, spindle assembly and chromosome separation abnormalities, indicating MV attenuates oocyte mature defects. We further observed that MV can effectively alleviate HS-induced cortical granule distribution abnormality and decrease of blastocyst formation rate after parthenogenesis activation. In addition, MV treatment reversed mitochondrial dysfunction and lipid droplet content decrease, reduced reactive oxygen species levels, early apoptosis and DNA damage in porcine oocytes after HS. Collectively, this study suggests that MV can effectively protect porcine oocytes from HS.

Numerical modelling of the viscoelastic polymer melt flow in material extrusion additive manufacturing

ABSTRACT In material extrusion (MEX), it is challenging to accurately predict the steady and transient feeding forces at various polymer extrusion rates when printing island and thin-walled structures involving rapid start/stop or acceleration/deceleration, especially for semi-crystalline polymers. This research presents a non-isothermal viscoelastic Computational Fluid Dynamics model to investigate the steady and transient feeding forces, as well as the phase transition process and viscoelastic behaviour of polylactic acid (PLA), a semi-crystalline polymer, during the extrusion process. The study establishes a relationship between polymer flow and viscoelastic stress, demonstrating that the elastic effect during extrusion is more significant than the viscous effect, particularly at higher feeding rates. Furthermore, the study uncovers critical aspects of PLA melt flow behaviour during the MEX process, laying the foundation for future research and optimisation of MEX printing processes.

In situ bioprinting for cartilage repair using a parallel manipulator

Regeneration of large-sized cartilage injury is a challenging endeavor. In vitro bioprinting for cartilage repair has several drawbacks, such as the tedious process of material preparation, potential contamination, and the mismatch between implant and defect. This study aimed to investigate the application of in situ bioprinting in cartilage repair using a parallel manipulator. In particular, the material extrusion rate and printing speed were adjusted to obtain the suitable forming parameters in a custom-made parallel manipulator. Cell experiments were conducted to determine the biocompatibility. Finally, a rabbit cartilage defect model was used to evaluate the feasibility of in situ bioprinting combined with machine vision. The results showed that to achieve optimum printing using the custom-made three-dimensional printer, 400–560 mm/min should be set as the standard printing speed, with an extrusion multiplier of 0.09–0.10. Cartilage defects can be precisely and easily segmented using a bimodal method with a 2% deviation error. In vitro experiments revealed that the utilized materials are highly biocompatible. Furthermore, according to the results from in vivo experiments, in situ bioprinting lends itself useful in the repair of cartilage defects. The overall results confirmed the feasibility of applying a parallel manipulator in in situ bioprinting for cartilage repair. Additional optimizations of the proposed approach are warranted prior to translation into clinical applications in the future.

Morphological transitions between lobate resurfacing and distal breakout lava flows in flood basalts: insights from analog experiments

Continental flood basalts (CFBs) are dominated by two characteristic lava morphologies. The first type, referred to as ‘compound’ or ‘hummocky pāhoehoe,’ exhibits pillow-like lava flow lobes with cross-sections of ~ 0.5–2 m and thin chilled margins. The second type, referred to as ‘simple’ or ‘sheet lobes’ preserves more massive, inflated flow interiors that are laterally continuous on scales of 100s of meters to kilometers. Previous hypotheses suggest that two factors may contribute to stratigraphic changes in morphology from ‘compound’ to ‘simple’: 1) increased eruption duration or 2) increased extrusion rate. We test the hypothesis that a large increase in extrusion rate would result in flow morphology transitioning from multiple small lobes to inflated sheet lobes due to a shift in flow propagation from intraflow resurfacing-dominated to marginal breakout-dominated. Using polyethylene glycol (PEG) wax extruded into a circular water-filled tank 130 cm in diameter, we produced larger, more complex experiments than previous studies. Our efforts simulated more complex lava fields which change flow morphology with distance from the eruptive vent, characteristic of CFBs. Whereas previous PEG studies linked extrusion rate to near-source surface morphologies, our experiments evaluated how flow propagation mechanisms change with variable extrusion rate and distance from the source. Two flow propagation styles were identified: 1) resurfacing, in which molten material breaks through the surface of a flow and covers the older crust and 2) marginal breakouts, in which molten material extends beyond the crust at the active distal margin of the flow. Flows that propagated via marginal breakouts were found to have lower proportions of resurfaced area and vice versa. We show that significant resurfacing is needed to preserve internal chilled boundaries within a flow and a low-extrusion-rate surface morphology, whereas marginal breakout-dominated flows tend to inflate the pillow-like surface morphology preserving a massive interior at great distances from the vent. Higher and more steady extrusion rates tend to decrease the extent of resurfacing and increase the distance between the source and preserved low-extrusion-rate surface morphologies. We find that an extrusion rate increase equivalent to a jump in the extrusion rate scaling factor, Ψ value, from < 1 to > 5 would be necessary to ensure a switch from resurfacing-dominated lobate morphologies to marginal breakout-dominated propagation style. This amounts to a factor of 125 increase in effusion rate for fissure eruptions and a factor of 625 for point source eruptions, assuming no change in vent geometry. This would be equivalent to an effusion rate of 0.2 m3/s, as documented in 1987–1990 Kīlauea eruptions, increasing to 125 m3/s, which was commonly measured during the 2014 Holuhraun eruption in Iceland and the 2018 eruption at Leilani Estates in Hawai‘i. Thus, we propose that continental flood basalts do not require unusually large effusion rates, but instead were active for a longer and more consistent time period than smaller-volume eruptions.

3D printed sweets made with peanut chenna and milk: A new frontier in food technology

AbstractThe recent development of three‐dimensional (3D) food printing technology is having an important impact on the food processing sector. This cutting‐edge method permits the manufacturing of foods with outstanding customization in terms of both look and nutritional profile. Several methods have been applied to demonstrate how 3D printing can be adopted in the food processing sector. These methods include selective laser sintering, hot‐melt extrusion, and inkjet printing. In contrast, high‐temperature techniques are not appropriate for constructing 3D representations of nutrients that are sensitive to changes in temperature. Cold extrusion is an effective alternative approach for 3D printing; however, its successful implementation requires the inclusion of rheology substitutes and the careful standardization of different elements involved in the process. In order to overcome this constraint, we utilized the technique of direct ink writing for 3D printing of the product by cold‐extrusion. This was achieved by using a combination for the different material formulations. This research provides confirmation on the feasibility of using 3D printing technology to print peanut based chenna, with the incorporation of skim milk (SM) powder, while maintaining a minimal material formulation. The flow properties of printing material compositions can be accurately explained with the R2 &gt; 0.996 Power‐law and Herschel–Bulkley model. The flow behavior index, denoted as n, (n &lt; 1), suggesting that the fluid exhibits shear thinning properties. The value of the loss modulus (G″) for material formulation was significantly lower than that of the storage modulus (G′). It was found that the storage modulus and the viscous modulus both emerged higher with increasing angular frequency. The formulation of the material, with its higher storage modulus indicating better durability, enables printing of a broad spectrum of food items. The primary objective of this study was to investigate the enhancement of printability in food compositions through the utilization of peanut‐based chenna. In order to achieve consistent and accurate results at different ratios (1:1, 2:1, and 3:1, w/w), a comprehensive evaluation was conducted on several printing parameters. These parameters included printing formulations, height of the nozzle, diameter, or size of nozzle, printing rate of speed, extrusion motor speed, and rate of extrusion. The extrusion printing parameters were adjusted to achieve optimal printing conditions for a 2:1 composition of SM powder and peanut‐based chenna. These parameters included the height of nozzle (0.314 mm), size of nozzle (0.4 mm), printing speed (30 mm/s), extrusion rate (5.21 mm3/s), extrusion motor speed (240 rpm), and extruder pressure (5 bar).Practical applicationsThe emergence of food printing is a game‐changer for the culinary world. 3D food printing has expanded the creative options available to chefs, bakers, and entrepreneurs in the food industry by making it possible to print unique and complex designs directly onto edible substrates. In this research, we looked into the material compositions, time standardization, extrusion rate, printing speed, and rheological properties of a food formulations. The present research uses a 3D food printer to explore the unexplored possibilities of a combination of peanut‐based chenna and SM for the purpose of product development.

Tracking seismicity in an underfunded institution: The case of La Soufrière St Vincent volcanic eruption 2020–2021

An unusual volcanic transition was recorded at La Soufrière Volcano in the Lesser Antilles during the 2020–2021 eruptive episode. Initial activity was an effusive phase that lasted three months and turned explosive on 9 April 2021. Although the transition was recognised when it occurred and people were timely evacuated thanks to the detection of subtle geophysical patterns, this work attempts to extract more detailed information from the seismic dataset to improve the monitoring of future events. Due to network limitations and the low amplitudes of the recorded signals, the elaboration of a conceptual model from earthquake locations turned out to be challenging. Accordingly, new analysis methods were developed, including: seismic interferometry using cross-correlation functions to locate the sources of tremor and explosions and a fluid-filled crack model to quantify the bulk modulus of magma stored in the system and translate it to gas content. Both are now applied in quasi-real time for the interpretation of future unrest. The VT locations feature a NNW-SSE alignment across the eruption site with focal depths shallower than 4 km. The banded tremor located at shallow levels (∼1 km depth) and the explosions featured two distinct behaviours, deepening of sources as the eruption progressed, as well as the activation of near-surface sources associated with the eruptive jet. A fluid-filled crack model points to an injection of gas into the system on 9 April, which amounts to approximately 76% gas-volume fraction. We propose a volatile injection equivalent to a 7% gas-volume fraction entering the system on 12 March; however, it was not energetic enough to produce changes in the extrusion rate. Seismological analyses support the conceptual model proposed by Joseph et al. (2022), where a dome sealed the system with a minimal amount of gas exsolved (0.7% gas-volume fraction). For the onset of the explosive phase, the system accumulated enough gases to produce the dome collapse and cleared the vent, decreased the internal pressure and triggered fragmentation.

Automatic in situ short-distance deposition of PLGA/PLLA composite nanofibrous membranes for personalized wound dressings.

Improving the mechanical properties of wound dressings and achieving personalized automatic real-time in situ deposition are important for accelerating wound management and repair. In this study, we report a self-designed automatic in situ deposition device based on solution blow spinning (SBS) to prepare poly(lactic-co-glycolic acid) (PLGA) and poly-L-lactic acid (PLLA) composite (PLGA/PLLA) nanofibrous membranes for wound dressing at a short distance. Polymer solution and in situ deposition conditions, including air pressure, spinning distance, solvent extrusion rate, and spinning rate, were optimized using orthogonal experiments and characterized via dynamic mechanical analysis. The microscopic morphology and physical properties of the prepared PLGA/PLLA composite nanofibrous membranes show that their strength, adhesion, water vapor transmission rate (WVTR), water retention, water absorption, degradation, and other properties were sufficient for wound-dressing applications. To investigate the possibility of a biomedical wound-dressing material, tannic acid (TA) was incorporated into the PLGA/PLLA composite nanofibrous membranes. The resultant PLGA/PLLA/TA composite nanofibrous membranes exhibited good biocompatibility and exceptional antibacterial properties against both Escherichia coli and Staphylococcus aureus. A pilot animal study illustrated the potential of this in situ deposition of PLGA/PLLA/TA composite nanofibrous membranes across multiple applications in wound healing/repair by reducing wound scar tissue formation and fibroblast overactivation.

Force-Induced Alignment of Nanofibrillated Bacterial Cellulose for the Enhancement of Cellulose Composite Macrofibers.

Bacterial cellulose, as an important renewable bioresource, exhibits excellent mechanical properties along with intrinsic biodegradability. It is expected to replace non-degradable plastics and reduce severe environmental pollution. In this study, using dry jet-wet spinning and stretching methods, we fabricate cellulose composite macrofibers using nanofibrillated bacterial cellulose (BCNFs) which were obtained by agitated fermentation. Ionic liquid (IL) was used as a solvent to perform wet spinning. In this process, force-induced alignment of BCNFs was applied to enhance the mechanical properties of the macrofibers. The results of scanning electron microscopy revealed the well-aligned structure of BCNF along the fiber axis. The fiber prepared with an extrusion rate of 30 m min-1 and a stretching ratio of 46% exhibited a strength of 174 MPa and a Young's modulus of 13.7 GPa. In addition, we investigated the co-spinning of carboxymethyl cellulose-containing BCNF with chitosan using IL as a "container", which indicated the compatibility of BCNFs with other polysaccharides. Recycling of the ionic liquid was also verified to validate the sustainability of our strategy. This study provides a scalable method to fabricate bacterial cellulose composite fibers, which can be applied in the textile or biomaterial industries with further functionalization.

Designing liquid metal microstructures through directed material extrusion additive manufacturing

Material extrusion (MEX) of soft, multifunctional composites consisting of liquid metal (LM) droplets can enable highly tailored properties for a range of applications from soft robotics to stretchable electronics. However, an understanding of how LM ink rheology and print process parameters can reconfigure LM droplet shape during MEX processing for in-situ control of properties and function is currently limited. Herein, the material (ink viscosity, and LM droplet size) and process (nozzle velocity, height from print bed, and extrusion rate) parameters are determined which control LM microstructure during MEX of these composites. The interplay and interdependence of these parameters is evaluated and nearly spherical LM droplets are transformed into highly elongated ellipsoidal shapes with an average aspect ratio of 12.4 by systematically tuning each individual parameter. Material and process relationships are established for the LM ink which show that an ink viscosity threshold should be fulfilled to program the LM microstructure from spherical to an ellipsoidal shape during MEX. Additionally, the thin oxide layer on the LM droplets is found to play a unique and critical role in the reconfiguration and retention of droplet shape. Finally, two quantitative design maps based on material and process parameters are presented to guide MEX additive manufacturing strategies for tuning liquid droplet architecture in LM-polymer inks. The insights gained from this study enable informed design of materials and manufacturing to control microstructure of emerging multifunctional soft composites.

Thread-analogous elastic fibers with liquid metal core by drawing at room temperature for multifunctional smart textiles

Stretchable and elastic conductive fibers with liquid metal core are appealing for integration into electronic fabrics and clothing, owing to their inherent electrical conductivity even under strain. Previously, injecting liquid metal into core of hollow elastic fiber has been utilized to fabricate conductive fibers, however, hydrodynamics limits the extent to which metals can be injected, thus limiting length and cross-sectional area. Although direct printing and spinning methods using coaxial needles have been utilized to fabricate long and thin polymer-encased liquid metal fibers via single step, various parameters including extrusion rate along with viscosity and surface tension of liquid metal and polymeric shell, needs to be considered. Herein, we introduce a simple and facile method for fabricating thread analogous conductive fibers by plastically deforming liquid metal injected polymeric shell via drawing at room temperature. This simple yet effective process generates long conductive fibers with narrow cross-sectional area of the liquid metal wire continuously formed along its length. The obtained fiber can withstand deformation arising from daily activities while maintaining excellent electrical performance, thus can be used for fabricating smart textiles serving multitude of purposes.

High Temperature-Induced m6A Epigenetic Changes Affect Early Porcine Embryonic Developmental Competence in Pigs.

N6-methyladenosine (m6A), the most prevalent modification in eukaryotic messenger RNA (mRNA), plays a key role in various developmental processes in mammals. Three proteins that affect RNA m6A modification have been identified: methyltransferases, demethylases, and m6A-binding proteins, known as "writer," "eraser," and "reader" proteins, respectively. However, changes in the m6A modification when early porcine embryos are exposed to stress remain unclear. In this study, we exposed porcine oocytes to a high temperature (HT, 41°C) for 10 h, after which the mature oocytes were parthenogenetically activated and cultured for 7 days to the blastocyst stage. HT significantly decreased the rates of the first polar body extrusion and blastocyst formation. Further detection of m6A modification found that HT can lead to increased expression levels of "reader," YTHDF2, and "writer," METTL3, and decreased expression levels of "eraser," FTO, resulting in an increased level of m6A modification in the embryos. Additionally, heat shock protein 70 (HSP70) is upregulated under HT conditions. Our study demonstrated that HT exposure alters m6A modification levels, which further affects early porcine embryonic development.

Exploring the Effects of Processing Parameters on the Flexural Performance of Polylactic Acid Fabricated through a Customized High Extrusion Rate Fused Filament Fabrication System

Exploring the Effects of Processing Parameters on the Flexural Performance of Polylactic Acid Fabricated through a Customized High Extrusion Rate Fused Filament Fabrication System

Epigallocatechin-3-gallate improves the quality of maternally aged oocytes.

The decline in female fertility as age advances is intricately linked to the diminished developmental potential of oocytes. Despite this challenge, the strategies available to enhance the quality of aged oocytes remain limited. Epigallocatechin-3-gallate (EGCG), characterised by its anti-inflammatory, antioxidant and tissue protective properties, holds promise as a candidate for improving the quality of maternally aged oocytes. In this study, we explored the precise impact and underlying mechanisms of EGCG on aged oocytes. EGCG exhibited the capacity to enhance the quality of aged oocytes both in vitro and in vivo. Specifically, the application of EGCG in vitro resulted in noteworthy improvements, including an increased rate of first polar body extrusion, enhanced mitochondrial function, refined spindle morphology and a reduction in oxidative stress. These beneficial effects were further validated by the improved fertility observed among aged mice. In addition, our findings propose that EGCG might augment the expression of Arf6. This augmentation, in turn, contributes to the assembly of spindle-associated F-actin, which can contribute to mitigate the aneuploidy induced by the disruption of spindle F-actin within aged oocytes. This work thus contributes not only to understanding the role of EGCG in bolstering oocyte health, but also underscores its potential as a therapeutic intervention to address fertility challenges associated with advanced age.

Nuclear-cytoplasmic asynchrony in oocyte maturation caused by TUBB8 variants via impairing microtubule function: a novel pathogenic mechanism

BackgroundTUBB8, a crucial gene encoding microtubule protein, plays a pivotal role in cellular processes. Deleterious TUBB8 variants have been shown to significantly hinder oocyte maturation. In this study, we conducted an in vitro investigation using TUBB8 mutant mouse oocytes to elucidate the pathogenic mechanisms of TUBB8 variants in oocyte nuclear and cytoplasmic maturation.MethodsA mutant model was successfully established in mouse oocytes via microinjection to further investigate the effects of four novel discovered TUBB8 mutations on the nuclear and cytoplasmic maturation of mouse oocytes. Immunofluorescence and confocal microscopy were performed to observe the cortical polarity and spindle and of mutant oocytes. Active mitochondrial staining was performed to analyze mitochondrial distribution patterns. Endoplasmic reticulum and Ca2+ staining were conducted to assess ER distribution and cytoplasmic calcium ion concentration in oocytes.ResultsIn mouse oocytes, TUBB8 variants (p.A313V, p.C239W, p.R251Q, and p.G96R) resulted in a reduction of the first polar body extrusion rate, disruption of spindle assembly, and abnormal chromosome distribution. Additionally, these variants induced oocyte organelle abnormalities, including anomalies in mitochondrial redistribution and endoplasmic reticulum stress compared to the wild-type.ConclusionDeleterious TUBB8 variants could disrupt microtubule function, affecting critical processes such as spindle assembly, chromosome distribution, and organelle rearrangement during oocyte meiosis. These disruptions culminate in compromised nuclear-cytoplasmic maturation, consequently giving rise to oocyte maturation defects.

Effect of slicing parameters on the light transmittance of 3D-printed polyethylene terephthalate glycol products

To manufacture 3D-printed polyethylene terephthalate glycol (PETG) products with excellent light transmittance performance, this study evaluated the principle of light transmission and the influencing factors of fused deposition methods (FDM) 3D-printed PETG products. This study explored the influence of different slicing parameters (layer height, extrusion rate, and printing speed) on the light transmittance of PETG products via a UV-visible spectrophotometer. The results showed that, in the range of 0.1 to 0.3 mm, the PETG specimens with 0.2 mm layer height had the best light transmittance performance; in the range of 100% to 120%; the PETG specimens with 110% extrusion rate had the best light transmittance performance; in the range of 20 to 40 mm/s printing speed, the PETG specimens with 40 mm/s printing speed had the best light transmittance performance. Comparison of image visibility showed that PETG products with layer height of 0.2 mm, extrusion rate of 110%, and printing speed of 40 mm/s had the best image visibility.

Three-dimensional glass scaffolds improve the In Vitro maturation of porcine cumulus-oocyte complexes and subsequent embryonic development after parthenogenetic activation

In vitro maturation (IVM) methods for porcine oocytes are still deficient in achieving full developmental capacity, as the currently available oocyte in vitro culture systems still have limitations. In vitro embryo production must also improve the porcine oocyte IVM system to acquire oocytes with good developmental potential. Herein, we tested a three-dimensional (3D) glass scaffold culture system for porcine oocyte maturation. After 42 h, we matured porcine cumulus-oocyte complexes (COCs) on either two-dimensional glass dishes (2D-B), two-dimensional microdrops (2D-W), or 3D glass scaffolds. The 3D glass scaffolds were tested for porcine oocyte maturation and embryonic development. Among these culture methods, the extended morphology of the 3D group maintained a 3D structure better than the 2D-B and 2D-W groups, which had flat COCs that grew close to the bottom of the culture vessel. The COCs of the 3D group had a higher cumulus expansion index and higher first polar body extrusion rate, cleavage rate, and blastocyst rate of parthenogenetic embryos than the 2D-B group. In the 3D group, the cumulus-expansion-related gene HAS2 and anti-apoptotic gene Bcl-2 were significantly upregulated (p < 0.05), while the pro-apoptotic gene Caspase3 was significantly downregulated (p < 0.05). The blastocysts of the 3D group had a higher relative expression of Bcl-2, Oct4, and Nanog than the other two groups (p < 0.05). The 3D group also had a more uniform distribution of mitochondrial membrane potential and mitochondria (p < 0.05), and its cytoplasmic active oxygen species content was much lower than that in the 2D-B group (p < 0.05). These results show that 3D glass scaffolds dramatically increased porcine oocyte maturation and embryonic development after parthenogenetic activation, providing a suitable culture model for porcine oocytes.

Hybrid Repair of a Medial Meniscus Mid-Body Radial Tear

Background: Meniscal radial tears are associated with altered contact mechanics, as they have the potential to disrupt the meniscal hoop stress mechanism. In prior studies, radial tears are associated with higher grade of cartilage damage, as well as higher rate and severity of meniscal extrusion in knees with a radial tear relative to other types of tears. Improved understanding of the meniscus biological potential together with modern developments in surgical technique has paved the way for the current emphasis on repairing even radial tears. Indication: Large or complete radial tears of the meniscus without prohibitive joint space narrowing or severe cartilage damage. Technique Description: A hybrid technique of meniscal radial repair is described, combining (1) 2 transtibial pullout cinch-loop sutures, (2) 2 inside-out vertical rip-stop sutures and 2 oblique sutures in a “cross-tag” configuration, and (3) 1 horizontal mattress all-inside suture. The repair is biologically augmented with a notch marrow-venting procedure. Results: Recent evidence has demonstrated significant biomechanical benefit in terms of increased load to failure and construct strength when adding transtibial tunnel augmentation to radial repairs. In addition, rip-stop sutures decrease the chance of cut-out relative to nonreinforced repairs. Those biomechanical advancements are reflected in excellent patient-reported outcomes as well as healing rates following radial repair. Discussion/Conclusion: We present a hybrid technique encompassing the most biomechanically effective novel radial repair techniques, backed by excellent clinical outcomes following radial repair in the current literature. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Voxel-based variable width continuous spiral path planning for 3D printing

Discontinuous printing paths in 3D printing lead to wasted time in fabricating products. This paper proposes a voxel-based continuous spiral path planning algorithm for 3D printing parts with less time consumption. Interestingly, we found our method can also improve the surface qualities and mechanical properties of the printed parts. The proposed path planning strategy in this paper is based on voxels which is different from traditional path planning strategies in literature. Firstly, our proposed algorithm determines the voxel size by considering the printable width of the printer nozzle. It then generates discrete elements by voxelizing the model and creates spirals and line segments by restricting the print direction of the connectable discrete elements. Next, the algorithm employs the Euler circuit to generate continuous sub-paths for the spirals and line segments. It utilizes the depth-first traversal algorithm to traverse and open the continuous sub-paths, resulting in printable continuous paths. To maintain surface accuracy for complex models, contour lines are introduced on the model's exterior and connected internally to ensure global path continuity. Lastly, the algorithm controls the path width in different directions by adjusting the extrusion rate of the printhead, preventing path overlap. Experimental results demonstrate that the proposed algorithm outperforms traditional path planning algorithms and the Connected Fermat spirals algorithm. The proposed strategy effectively mitigates the negative effects of path discontinuity, reduces printing time, and improves printed accuracy, and mechanical properties.