Changes In Diameter Research Articles

Effect of laser focal point position on porosity and melt pool geometry in laser powder bed fusion additive manufacturing

In laser powder bed fusion (PBF-LB) additive manufacturing (AM), the laser beam is the fundamental tool used to selectively melt metal powder layer-upon-layer to form a 3-dimensional part. Studies on the effect of the laser scanning parameters (power, speed, hatch distance, and scanning strategy in general) on part quality are abundant; however, far less emphasis has been given to the effect of the laser beam and how it is focused on the laser-material interaction plane. Here, we have studied the effect of laser beam focal point position on porosity and melt pool geometry in PBF-LB AM. In addition, we also study how the various energy density parameters developed for laser melting processes correlate with melt pool dimensions in a situation where the laser beam focal point position (and the beam diameter and laser intensity change at work plane caused by it), is taken into consideration. Furthermore, we assess the possibility of using co-axial, photodiode-based melt pool monitoring signals as a means to monitor the thermal emissions of the process, and how it correlates with the resulting melt pool geometry. It was found that melt pool penetration experiences a major decrease when the focal point position is shifted by more than ±1 mm (or 30% of Rayleigh length), which could be considered as a tolerance limit for acceptable focus shift in PBF-LB machines. Focus shifts larger than this were effectively captured by the photodiode signals, indicating the potential of using such photodiode-based melt pool monitoring systems for continuous monitoring of focus shift in PBF-LB AM. Finally, it was shown that all the studied energy density parameters, except volumetric energy density, were able to capture the trend in normalized melt pool dimensions when focus position is introduced as a variable. A new energy density metric by normalizing the melt pool monitoring signal intensity with the beam area was introduced and shown to correlate with the normalized melt pool dimensions.

Measurement System for Compliance in Tubular Structures

Tubular structures such as blood vessels, intestines, and the trachea are common in various life forms. This paper describes a measurement system to test the mechanical compliance of tubular structures. The novelty of the system lies in its hardware and software. Here we use vascular graft as an example to demonstrate the utility of the system. A fully synthetic vascular graft would ideally mimic the mechanical and architectural properties of a native blood vessel. Therefore, mechanical testing of the graft material under physiological pressure is crucial to characterizing its potential in vivo performance. The device operates through a low-cost Arduino-based control system that simulates and measures cyclic fluid pressure changes over time and a laser micrometer that measures diameter changes with pressure. This system is low-cost, assuming one already has access to a laser micrometer. In contrast to previous methods, this system offers a simple, low-cost, and customizable option to measure compliance and is equipped with data acquisition/analysis programs. These programs include a MATLAB application that processes and synchronizes Arduino Uno pressure signals and LabChart Pro diameter readings. Lastly, this paper explains the hardware and software of the measurement system. The system is beneficial for testing the pressure-diameter relationship of tubular structures of varying sizes and materials. KEYWORDS: Tubular Structures; Compliance; Data Acquisition System; Physiological Pressure; Diameter Change; Arduino Uno; LabChart Pro; MATLAB

Management of undifferentiated embryonal sarcoma of the liver: A Pediatric Surgical Oncology Research Collaborative study.

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative. Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event-free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively. Seventy-eight patients were identified with a median age of 9.9years [interquartile range [IQR): 7-12]. Twenty-seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6cm [IQR: 0.0-4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04-0.6]. At a median follow-up of 4years [IQR: 2-8], the EFS was 70.0% [95% CI: 60%-82%] and OS was 83% [95% CI: 75%-93%]. Complete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

Electrochemical activation of venus flytrap-like CoP and Co3O4 for boosting the supercapacitance performance

Electrochemical activation tactic can be adopted to boost electrochemical performance of electrodes by adjusting the composition and microstructure. Herein, venus flytrap-like CoP nanostructures and corresponding Co3O4 precursor are synthesized on nickel foam (NF) framework, and the electrochemical activation mechanisms of CoP and Co3O4 are investigated in KOH electrolyte. When endured for 100 CV cycles, the activated CoP exhibits a 3D framework structure consisted of thin nanosheets, and the discharge capacity enhances to 1536 C g−1 at 1 A g−1 from initial capacity of 663 C g−1. The enhanced performance is due to the composition transition from upper CoP and beneath NiP to NiCo-hydroxides and NiCoOOH, and the microstructure transition from nanoneedles to 3D framework structure stacked by thin nanosheets. Different from the transition mechanism of NF/CoP, seldom microstructure transitions are occurred for the Co3O4 precursor, only involving the change of nanoneedle diameter. The activation of Co3O4 induces a limited capacity enhancement from 242 to 623 C g−1, due to a simple transition from oxides to oxyhydroxides. The application performance of NF/CoP is investigated by assembling asymmetric supercapacitor with NF/AC. The device releases a discharge capacitance of 137 F g−1 at 1 A g−1, and the capacitance retention is 77.4% when cycling for 5000 cycles. The energy density is 48.7 W h kg−1 at 804.4 W kg−1. Compared with existing Co-based phosphides, activated NF/CoP electrode exhibits an obvious performance advantage in supercapacitors.

Helmet therapy efficacy and its prediction in Japanese infants with positional plagio- and brachycephaly.

To provide additional information on optimal start times and therapeutic effectiveness based on treatment outcome of Japanese infants with positional plagio- and brachycephaly (PPB) receiving cranial molding helmet therapy (CMHT). In this retrospective cohort study, data from a 3D head scanning system was analyzed from 2173 Japanese infants who completed CMHT. Anterior and posterior symmetry ratio (ASR and PSR) and longitudinal to transverse diagonal ratios (LD/TDR) were calculated based on skull shape at helmet design and at completion of therapy. The outcomes were evaluated using the regression analysis and a predictive model using cranial parameters was developed. The earlier the start of therapy, the greater the therapeutic effect on ASR, PSR, and LD/TDR (ASR, -0.134 percent points (ppt)/day; PSR, -0.086 ppt/day; and LD/TDR, -0.131 ppt/day). In the predictive model, in addition to starting age of the therapy, sex (male), the degree of deformity of the head (DoD) (moderate and severe), quadrant volume, PSR, and head circumference at the start of treatment also had a positive effect on changes in ASR, DoD (moderate and severe), ASR, LD/TDR and transverse diameter for PSR, sex (male), DoD (moderate), quadrant volume, PSR, and head circumference for LD/TDR. The starting age of therapy had a relatively smaller contribution to outcome effects. Applying the cranial parameter obtained at the start of treatment to the predictive model helps to predict the effect of CMHT and whether PPB can be treated with CMHT in infants of older age.

Optimization of Polycaprolactone and Type I Collagen Scaffold for Tendon Tissue Regeneration.

Introduction Collagen synthesis is vital for restoring musculoskeletal tissues, particularly in tendon and ligamentous structures. Tissue engineering utilizes scaffolds for cell adhesion and differentiation. Although synthetic scaffolds offer initial strength, their long-term stability is surpassed by biological scaffolds. Combining polycaprolactone (PCL) toughness with collagen in scaffold design, this study refines fabrication via electrospinning, aiming to deliver enduring biomimetic matrices for widespread applications in musculoskeletal repair. Methods Electrospinning employed four solutions with varied collagen and PCL concentrations, dissolved in chloroform, methanol, and hexafluoro-2-propanol. Solutions were combined to yield 60 mg/mL concentrations with different collagen/PCL ratios. Electrospinning at 12-14kV voltage produced scaffolds, followed by vacuum-drying. Collagen coating was applied to PCL and 15% collagen/PCL scaffolds using a 0.1% collagen solution. SEM characterized fiber morphology, tensile testing was conducted to determine the mechanical properties of the scaffold, and Fourier-transform infrared (FTIR) spectroscopy analyzed scaffold composition. Atomic force microscopy (AFM) analyzed the stiffness properties of individual fibers, and a finite element model was developed to predict the mechanical properties. Cell culture involved seeding human bone marrow mesenchymal stem cells onto scaffolds, which were assessed through Alamar Blue assay and confocal imaging. Results Various scaffolds (100% PCL, PCL-15% collagen, PCL-25% collagen, PCL-35% collagen) were fabricated to emulate the extracellular matrix, revealing collagen's impact on fiber diameter reduction with increasing concentration. Tensile testing highlighted collagen's initial enhancement of mechanical strength, followed by a decline beyond PCL-15% collagen. FTIR spectroscopy detected potential hydrogen bonding between collagen and PCL. A finite element model predicted scaffold response to external forces which was validated by the tensile test data. Cell viability and proliferation assays demonstrated successful plating on all scaffolds, with optimal proliferation observed in PCL-25% collagen. Confocal imaging confirmed stem cell integration into the three-dimensional material. Collagen coating preserved nanofiber morphology, with no significant changes in diameter. Coating of collagen significantly altered the tensile strength of the scaffolds at the macro scale. AFM highlighted stiffness differences between PCL and collagen-coated PCL mats at the single fiber scale. The coating process did not significantly enhance initial cell attachment but promoted increased proliferation on collagen-coated PCL scaffolds. Conclusion The study reveals collagen-induced mechanical and morphological alterations, influencing fiber alignment, diameter, and chemical composition while emphasizing scaffolds' vital role in providing a controlled niche for stem cell proliferation and differentiation. The optimization of each of these scaffold characteristics and subsequent finite element modeling can lead to highly repeatable and ideal scaffold properties for stem cell integration and proliferation.

Development of quantitative structure activity relationships (QSARs) for predicting the aggregation of TiO2 nanoparticles under favorable conditions

This study developed multi-linear regression (MLR) quantitative structure-activity relationships (QSARs) to predict n-TiO2 aggregation in the presence of high concentrations of representative emerging organic contaminants (EOCs), which presented favorable conditions to interaction with n-TiO2. The largest diameter change (Δ 517 nm at 0 h and Δ 1164 nm at 12 h) of n-TiO2 was observed by estrone, while the smallest diameter change (Δ −114 nm at 0 h and – 4 nm at 12 h) was observed by lincomycin during experimental periods. In addition, the zeta potential changes of n-TiO2 were observed that the biggest changes were observed by 17β-estradiol (−1.3 mV) and alachlor (−10.02 mV) at 0 h, while 17β-estradiol (−1.31 mV) and pendimethalin (−11.4 mV) showed the biggest changes at 12 h comparing to control. These changes of n-TiO2 diameter and zeta potential may implicate the effects of unique physico-chemical properties of each EOC on the surface modification of n-TiO2. Based on the interaction results, this study investigated the QSARs between n-TiO2 aggregation and physico-chemical descriptors of EOCs with 7 representative descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., # of HBD) for predicting n-TiO2 aggregation rate kinetics at 0 h and 12 h by applying MATLAB statistical methods (model 1 - fitlm and model 2 - stepwiselm). In a model 1, QSARs showed the good coefficients of determination (R2 = 0.92) at 0 h and (R2 = 0.87) at 12 h with 7 descriptors. In a model 2, QSARs showed the goodness of fit of a model (R2 = 0.9998) with 8 descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., #HBD, pKa⋅#H bond donors) at 0 h, while QSARs showed the coefficients of determination (R2 = 0.68) with 2 descriptors (pKa, M.V.) at 12 h. Particularly, we observed that some descriptors of EOCs such as pKa and # of HBD having polarity have more influenced on the n-TiO2 aggregation rate kinetics. Our developed QSARs demonstrated that the 7 descriptors of EOCs were significantly effective descriptors for predicting n-TiO2 aggregation rate kinetics in favorable conditions, which may implicate the complexity interactions between heterogeneous surfaces of n-TiO2 and physico-chemical properties of EOCs.

Abstract 1944: Using patient-derived cancer organoids to determine the effects of the anti-EGFR therapy panitumumab in the presence or absence of KRAS mutation

Abstract Introduction: Tumor heterogeneity is a major cause of resistance to therapies in colorectal cancer (CRC). The anti-EGFR (epidermal growth factor receptor) therapies panitumumab (pani) and cetuximab, are now being investigated for the retreatment of patients when resistant subclones could be more abundant in a previously wild-type cancer. Here we utilize patient-derived cancer organoids (PDCOs) to investigate the potential implications of the abundance of resistant subclones on treatment and duration of response. Methods: Two CRC PDCO lines, one pani sensitive (PS) and one pani resistant (PR), were cultured separately and then mixed to determine how different combinations of mutations altered the time for the overall culture to be resistant to pani. NGS was performed on these cells to determine the mutation profile. The two PDCO lines were cultured together with the following concentrations (v/v) of 100% PS; 20% PR+80% PS; 10% PR+90% PS, 5% PR+95% PS, 1% PR+99% PS, and 100% PR using Matrigel and fed with previously published CRC organoid media. Widefield imaging was performed for diameter change analysis at day 0 and day 4 using ImageJ. Upon a median growth of >20% at baseline/untreated, all mixed populations were treated at increments of 20% physiologic Cmax of pani each week. Once select mixed populations reached 100% Cmax and maintained a median growth of >20% for two consecutive weeks, they were determined to have reached complete resistance to the treatment. Results: DNA sequencing of PDCOs showed PR has mutations associated with pani resistance (KRASG12V, PIK3CAH1047R) and the PS line did not. All the conditions except for 100% PS escalated to ≥40% Cmax within 7 weeks and reached complete resistance to pani by week 22. 100% PS remained at 20% Cmax through week 22. The 100% PR population reached complete resistance to pani the quickest at 100% Cmax at week 8. The conditions with the lowest percentages of PR (5% PR+95% PS and 1% PR+99% PS already started to show resistance above the PS line by 8 weeks and reached complete resistance to pani at week 12. Conclusion: PDCO lines containing low concentrations of resistant clones can quickly lead to resistance to pani treatment, even below the typical level for clinical NGS detection. All KRAS mutant conditions (PR) reached resistance quicker than 100% PS condition. Further studies will evaluate even low concentrations of resistance clones across further CRC PDCO models and will evaluate the mechanism by which these clones are leading to resistance. Citation Format: Jordan N. Stoecker, Shirsa Udgata, Amani A. Gillette, Cheri A. Pasch, Melissa C. Skala, Dustin A. Deming. Using patient-derived cancer organoids to determine the effects of the anti-EGFR therapy panitumumab in the presence or absence of KRAS mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1944.

Study on crack resistance of self-healing microcapsules in asphalt pavement by multi-scale method.

Self-healing microcapsules in the asphalt pavement must be kept intact under vehicle load to ensure there is enough rejuvenator in capsules when cracks appear in asphalt pavement. In this paper, the crack resistance of self-healing microcapsules in asphalt pavement was evaluated. Firstly, an expanding multi-scale analysis was conducted based on proposed mesoscopic mechanical models with the aim to determine the mechanical parameters for the following contracting multi-scale analysis. Secondly, the periodic boundary condition was introduced for the contracting multi-scale analysis and the stress field of the capsule wall was obtained. Finally, the effects of the design parameters of the microcapsule on its crack resistance in asphalt pavement were investigated. The results showed that the incorporation of microcapsules has almost no effect on the elastic constants of the asphalt mixture. The core could be simplified as an approximately incompressible solid with the elastic constants determined by the proposed mesoscopic mechanical model. With the increase of the modulus of the capsule wall, the mean maximum tensile stress of the capsule wall increased from 0.372 MPa to 0.465 MPa, while with the decrease of the relative radius of the capsule core, the mean maximum tensile stress of the capsule wall increased from 0.349 MPa to 0.461 MPa. The change in the mean maximum tensile stress of the capsule wall caused by the change of capsule diameter was within 5%. The relative radius of the capsule core and the elastic modulus of capsule wall were two key parameters in capsule design. Besides, the microcapsules with the wall made of resin would not crack under the vehicle load before microcracks occurred in asphalt pavement.

Numerical investigations on the impact of metallic foam configurations on heat transfer in double tube heat exchanger: A parametric approach

In this research, a parametric analysis of partially filled high-porosity metallic foams within a double-tube heat exchanger integrated into a solar flat plate collector is conducted. The primary objective is to comprehensively analyze the thermal and fluid flow behavior in this complex system through numerical simulations employing ANSYS Fluent v2021, with water as the working fluid. The study encompasses three distinct metal foam materials—Nickel, Copper, and Aluminum—each investigated across six cases with varying porosities (ranging from 0.80 to 0.90) and pore densities (ranging from 10 to 30). The investigation also explores changes in the internal diameter of the foams adjacent to the conduit wall and the external diameter of the foam within the tube core, resulting in multiple test cases. Rigorous validation of simulation results against experimental data enhances the credibility of the findings. To simulate fluid flow and heat transfer phenomena within the metal foam heat exchanger’s intricate geometry, the research leverages the Reynolds-Averaged Navier-Stokes (RANS) equations coupled with the k-epsilon model, treating the metal foam as a porous medium. The outcomes reveal intriguing insights, such as the close thermal performance match between 10 PPI aluminum foam and the more costly 10 PPI copper foam. The highest performance factor is observed for 30 PPI aluminum foam, highlighting its efficiency. However, the performance factor exhibits variations, with values of 2.03, 3.15, and 3.73 for 100 PPI, 20 PPI, and 30 PPI foams, respectively, and their corresponding porosities of 0.90, 0.85, and 0.80 in case 1, case 2, and case 3, all at a lower Reynolds number of 3,000. This performance factor decreases progressively with increasing fluid flow rates. Additionally, the research evaluates key parameters, including average wall temperature, average Nusselt number, and Colburn j factor, to identify the optimal performance characteristics within the investigated configurations. This study provides valuable insights into the potential for enhancing the efficiency of heat exchangers in solar flat plate collectors through the strategic utilization of high-porosity metallic foams.

Influence of Drought Stress and Foliar Application of Salicylic Acid on Early Vegetative Stage of Cacao

Cacao (Theobroma cacao L.) is noted to have a low tolerance to drought and is, therefore, not resilient to prolonged dry periods. The study sought to evaluate the morpho-anatomical and physiological responses of two clonal seedlings of cacao BR25 and K9 under drought stress and to explore the potential alleviating effects of salicylic acid (SA) at concentrations of 0.5 and 1.0 mM on the early vegetative stage. Eleven-month-old BR25 and K9 cacao were pre-treated with foliar application of 0.5 and 1.0-mM SA for 2 wk before the onset of drought conditions. Well-watered and drought seedlings with no pre-treatments served as the control. Water was withheld for 20 d, after which rewatering resumed for 3 mo. Results revealed that after 20 d of drought, both clonal varieties experienced a significant decline in relative water content (RWC) and increased ascorbate peroxidase (APX) and catalase activity. Changes in stem diameter were observed after a rewatering period of 3 mo. K9 exhibited a noticeable reduction in root and shoot dry weight and stomatal aperture after 20 d of drought, whereas BR25 showed a decrease in total chlorophyll content and chlorophylls a and b. Furthermore, the results of the study suggest that 0.5-mM SA has the potential to mitigate the drastic effects during drought in BR25 and K9 cacao by improving RWC, stomatal length, and width. On the other hand, 1.0- mM SA has the potential to alleviate the effects of drought experienced earlier on by improving root dry weight and APX activities of the seedlings.

Vascular Remodeling During Late-Gestation Pregnancy: An In-Vitro Assessment of the Murine Ascending Thoracic Aorta.

Maternal mortality due to cardiovascular disease is a rising concern in the U.S. Pregnancy triggers changes in the circulatory system, potentially influencing the structure of the central vasculature. Evidence suggests a link between a woman's pregnancy history and future cardiovascular health, but our understanding remains limited. To fill this gap, we examined the passive mechanics of the murine ascending thoracic aorta during late gestation. By performing biaxial mechanical testing on the ascending aorta, we were able to characterize the mechanical properties of both control and late-gestation tissues. By examining mechanical, structural, and geometric properties, we confirmed that remodeling of the aortic wall occurred. Morphological and mechanical properties of the tissue indicated an outward expansion of the tissue, as reflected in changes in wall thickness (∼12% increase) and luminal diameter (∼6% increase) at its physiologically loaded state in the pregnant group. With these geometric adaptations and despite increased hemodynamic loads, pregnancy did not induce significant changes in the tensile wall stress at the similar physiological pressure levels of the pregnant and control tissues. The alterations also included reduced intrinsic stiffness in the circumferential direction (∼18%) and reduced structural stiffness (∼26%) in the pregnant group. The observed vascular remodeling maintained the elastic stored energy of the aortic wall under systolic loads, indicating preservation of vascular function. Data from our study of pregnancy-related vascular remodeling will provide valuable insights for future investigations of maternal cardiovascular health.

Side branch embolization before endovascular abdominal aortic aneurysm repair to prevent type II endoleak: A prospective multicenter study

PurposeThe purpose of the study was to evaluate the efficacy and safety of pre-emptive transcatheter arterial embolization (P-TAE) of aortic side branches to prevent type II endoleak in patients with abdominal aortic aneurysm after endovascular abdominal aneurysm repair (EVAR). Materials and methodsThis multicenter, prospective, single-arm trial enrolled 100 patients with abdominal aortic aneurysm from nine hospitals between 2018 and 2021. There were 85 men and 15 women, with a mean age of 79.6 ± 6.0 (standard deviation) years (range: 65–97 years). P-TAE was attempted for patent aortic side branches, including the inferior mesenteric artery, lumbar arteries, and other branches. The primary endpoint was late type II endoleak incidence at 6 months post-repair. Secondary endpoints included changes in aneurysmal sac diameter at 6- and 12 months, complications, re-intervention, and aneurysm-related mortality. Aneurysm sac changes at 6- and 12 months was compared between the late and no-late type II endoleak groups. ResultsCoil embolization was successful in 80.9% (321/397) of patent aortic side branches, including 86.3% of the inferior mesenteric arteries, 80.3% of lumbar arteries, and 55.6% of other branches without severe adverse events. Late type II endoleak incidence at 6 months was 8.9% (8/90; 95% confidence interval: 3.9–16.8%). Aneurysm sac shrinkage > 5 mm was observed in 41.1% (37/90) and 55.3% (47/85) of the patients at 6- and 12-months post-EVAR, respectively. Patients with late type II endoleak had less aneurysm sac shrinkage than those without type II endoleak at 12 months (˗0.2 mm vs. ˗6.0 mm; P = 0.040). No patients required re-intervention for type II endoleak, and no aneurysm-related mortalities occurred. ConclusionP-TAE is safe and effective in preventing type II endoleak, leading to early sac shrinkage at 12 months following EVAR.

Characterization of Nanoporous Poly(Lactic Acid) Microfibers Using a Simplified Centrifugal Spinning Method

In recent years, great attention has been paid to the development of porous materials with excellent reactivity and absorbency. The poly(lactic acid) (PLA) microfibers with uniform nanopores were successfully prepared by rotary centrifugal spinning using PLA/chloroform solution. Previous research showed that PLA microfibers have extremely high oil absorbing capacity. In this study, the changes in fiber diameter and nanopore diameter of nanoporous PLA microfibers under different fabrication conditions and the adsorption capacity of Prussian blue nanoparticles were systematically evaluated. The results showed that the fiber diameter increased with increasing PLA/chloroform solution concentration. Furthermore, it was found that the amount of adsorbed Prussian blue nanoparticles increased with the increase in fiber diameter. Prussian blue nanoparticles are known to adsorb radioactive materials such as cesium, and are expected to be applied to the recovery of cesium diffused in the atmosphere and ocean.

P258: Does The Latarjet Procedure For Anterior Shoulder Instability Put Off-Track Lesions Back On Track: A Systematic Review

Abstract Introduction The Latarjet procedure is commonly used in the treatment of shoulder instability for high risk patients. The glenoid track is widened by fixing the coracoid to the anterior glenoid. In the presence of bipolar bone loss there is concern that the Latarjet procedure may not adequately address off-track lessions.The aim of this systematic review to assess whether the Latarjet procedure is sufficient to convert 'off-track' Hill-Sachs lesions back to 'on-track'. Methods A systematic review of Pubmed, Embase and the Cochrane Library was performed in October 2023. The primary outcome was the rate of post-operative 'on-track' lesions and of recurrent instability. Changes in glenoid diameter and Hill-Sachs lesion interval were also recorded. Results A total of 5 studies were included with 187 patients. Weighted mean age was 29.2 ± 2.2 years old and 90.8% of patients were male. The mean follow-up time was 26.8 months. All patients had off-track Hill-Sachs lesions pre-operatively. 88.6% of cases were converted to on-track lesions. The overall post-operative instability rate was 4.8%. The recurrence rate was significantly greater for off-track lesions (33.3%) than for on-track lesions (4.2%), odds ratio 11.4 (3.5-37.0). The weighted mean post-operative glenoid diameter change was 8.4 ± 5.8mm. The weighted mean Hill-Sachs lesion interval was 25.6 ± 4.5mm. Conclusion The Latarjet procedure results in the majority of Hill-Sachs lesions being converted to on-track lesions. However, due to bipolar bone loss approximately 1/9 cases will remain off track. In cases of failure to return on-track, there is an unacceptably high rate of recurrent instability (33.3%).

Analysis of the causes determining dimensional and geometrical errors in 316L and 17-4PH stainless steel parts fabricated by metal binder jetting

This work aims at investigating the causes affecting the dimensional and geometrical accuracy of holes in metal binder jetting stainless steel parts. Parallelepiped samples with a through hole were produced using AISI 316L and 17-4PH powders, differing for diameter (3, 4, 5 mm), and position of the axes with respect to the building plane (6, 9, 12 mm distance). Dimensions and geometrical characteristics were measured at green and sintered state by a coordinate measuring machine, determining the dimensional change and the geometrical characteristics. As expected, the shrinkage of linear dimensions is anisotropic; moreover, change in volume and sintered density are significantly affected by the position in the printing chamber. Higher shrinkage was measured along building direction (Z) – 18.5 ÷ 19.5%, than in the building plane – 16.5 ÷ 17.5%, and slightly higher shrinkage – 0.5 ÷ 0.8% was measured along powder spreading direction (X) than binder injection direction (Y). A variation up to 3% in relative density of sintered parts depending on the position in the building plane was observed in 316L. The dimensional change of diameters generally confirmed the shrinkage predicted by the model previously developed—difference between real and expected dimensional changes lower than 3%, except for three geometries (4 ÷ 6%). The cylindricity form error of sintered parts was strongly underestimated by the prediction model (up to 0.15 mm), but underestimation was considerably reduced (generally lower than 0.05 mm) adding the cylindricity form error due to printing. Dimensional and geometrical accuracy of holes are strongly affected by shape distortion of the parallelepiped geometry, in turn due to layer shifting and inhomogeneous green density during printing, and to the effect of frictional forces with trays during sintering. Gravity load effect was also observed on the holes closest to the building plane. Future work will improve the reliability of the prediction model implementing the results of the present work.

Dissolution behavior of chromite mineral impurities in raw materials of glass production using scanning electron microscopy-energy dispersive spectrometer, X-ray fluorescence spectroscopy and Raman spectroscopy methods

Silica sand is an essential raw material for glass production. The specification of silica sand for each type of glass is the most important point, such as chemical purity, grain size, grain shape, and their impurities. Some of the impurities in the sand can be eliminated by processing yet some cannot be avoided. This paper indicates that as an impurity in the sand, chromite minerals dissolve in glass. 0.200 mm and 0.250 mm grain size chromite minerals were observed grain size change at 1350 °C − 1400 °C − 1450 °C. With increasing in temperature, the rate of size change in the grain diameter increased. Because of the chemical composition of chromite mineral, with increasing temperature, first of all, aluminum and magnesium content start to dissolve in soda lime silicate glass. Then, chromium content transforms into chromium oxide. The transformation rate depends on the mineral composition as well as the temperature and the residence time in the furnace. This paper concerns the chemical composition of the chromite by scanning electron microscopy equipped with energy dispersive spectrometer, the compositions of the raw material analyzed with X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectrometer and chromite characteristics analyzed by Raman Spectroscopy methods.

Laparoscopic pyeloplasty for newborns with severe hydronephrosis.

We aimed to investigate the short-term efficacy and safety of laparoscopic pyeloplasty for treating newborns with severe hydronephrosis due to ureteropelvic junction obstruction (UPJO). A retrospective analysis was performed on 16 newborn patients with severe neonatal hydronephrosis who underwent laparoscopic pyeloplasty at our hospital from January 2021 to November 2022. All patients were regularly followed up. Laparoscopic pyeloplasty with double J stent placement was performed after the presence of severe hydronephrosis was confirmed. Among the 16 pediatric patients (13 males, 3 females), the left side was affected in 13 cases and the right side in 3. The average age at surgery was 9.50 (8.50-12.00) days, with an average weight of 3.30 ± 0.95 kg. Laparoscopic pyeloplasty was performed in all cases without the need for open conversion. The mean surgery duration was 292.06 ± 73.60 min, with minimal blood loss (2.50, 2.00-5.00 ml). Postoperative hospital stays averaged 13.44 ± 4.70 days. No anastomotic leakage occurred, and follow-ups at 1, 3, 6, and 12 months showed no stent displacement, except for one case where the stent was removed at 1 month, and the others at 3 months. There were no cases of worsened hydronephrosis, except for one with renal atrophy at the 6-month follow-up. Changes in renal pelvis anteroposterior diameter exhibited a time effect (F = 49.281, P < 0.001), with significant differences at 1, 3, 6, and 12 months postoperatively compared to preoperative values (P < 0.05). Notably, differences were observed between 6 and 3 months, as well as between 12 and 3 months postoperatively (P < 0.05). Similarly, renal parenchymal thickness changes showed a time effect Pediatric urology, Guangdong Women and Children Hospital, Guangzhou, China (F = 49.281, P < 0.001), with significant differences at 1, 3, 6, and 12 months postoperatively compared to preoperative values (P < 0.05). Significant differences were also noted between 6 and 1 month, as well as between 12 and 1 month postoperatively (P < 0.05). There was one case of urinary tract infection after surgery, and no case of recurrence was observed. Severe neonatal hydronephrosis must be treated promptly. Laparoscopic pyeloplasty is a safe and feasible treatment with minimal complications for newborn patients with severe hydronephrosis due to UPJO.

Enhanced Ability of Agarwood Leaves (Aquilaria malaccensis Lam.) Ointment as Wound Healing to Heal Second-Degree Burns in Rats

Agarwood leaves (Aquilaria malaccensis Lam.) contain chemical substances such as alkaloids, flavonoids, and triterpenoids that contribute to the healing process of burns. This study aims to evaluate the wound healing activity of spray-dried extract from agarwood leaves formulated into an ointment for second-degree burns. The method involves extracting agarwood leaves through the decoction method, followed by spray drying, and subsequent evaluation of the extract. The prepared extract was then formulated into an ointment and tested for wound healing activity on 24 white rats of the Sprague-Dawley strain, divided into four groups, each consisting of 6 rats: negative control (ointment base), positive control (Betadine®), formula 1 (agarwood leaves extract ointment with 20% extract concentration - ALO-20), and formula 2 (agarwood leaves extract ointment with 30% extract concentration - ALO-30). Second-degree burns were induced by exposing the rats' backs to ferrous metal for 3 seconds and treating them for 14 days. Observations were made by assessing changes in burn diameter and scab formation. In this study, ALO-30 demonstrated superior activity. Scab formation was faster on day 3, and the burn diameter was reduced by day 7. The results indicated that ALO-30 led to a quicker reduction in wound diameter compared to ALO-20 and the negative control. Agarwood leaves extract ointment with a concentration of 30% (ALO-30) exhibited a more effective wound healing effect than the ointment with a 20% concentration (ALO-20).

Effect of digital ocular massage on intraocular pressure and Schlemm’s canal dimensions

Digital ocular massage has been reported to temporarily lower intraocular pressure (IOP). This could be related to an enhanced aqueous humor outflow; however, the mechanism is not clearly understood. Using anterior segment optical coherence tomography, the Schlemm’s canal (SC) and trabecular meshwork (TM) can be imaged and measured. Here, 66 healthy adults underwent digital ocular massage for 10 min in their right eyes. The IOP and dimensions of the SC and TM were measured before and after ocular massage. All subjects demonstrated IOP reduction from 15.7 ± 2.5 mmHg at baseline to 9.6 ± 2.2 mmHg immediately after, and median of 11.6 mmHg 5-min after ocular massage (Friedman’s test, p < 0.001). There was significant change in SC area (median 10,063.5 μm2 at baseline to median 10,151.0 μm2 after ocular massage, Wilcoxon test, p = 0.02), and TM thickness (median 149.8 μm at baseline to 144.6 ± 25.3 μm after ocular massage, Wilcoxon test, p = 0.036). One-third of the subjects demonstrated collapse of the SC area (−2 to −52%), while two-thirds showed expansion of the SC area (2 to 168%). There were no significant changes in SC diameter (270.4 ± 84.1 μm vs. 276.5 ± 68.7 μm, paired t-test, p = 0.499), and TM width (733.3 ± 110.1 μm vs. 733.5 ± 111.6 μm, paired t-test, p = 0.988). Eyes with a higher baseline IOP demonstrated a greater IOP reduction (Pearson correlation coefficient r = −0.521, p < 0.001). Eyes with smaller SC area at baseline showed greater SC area expansion (Pearson correlation coefficient = −0.389, p < 0.001). Greater IOP reduction appeared in eyes with greater SC area expansion (Pearson correlation coefficient r = −0.306, p = 0.01). Association between change in IOP and change in TM thickness was not significant (Spearman’s ρ = 0.015, p = 0.902). Simple digital ocular massage is an effective method to lower IOP values, and change in the SC area was significantly associated with IOP changes.