Softening Kinetics of Plain Carbon Steels Containing Dilute Nb Additions

The recrystallisation and precipitation kinetics of a plain carbon steel with 0.017 % Nb were studied using the double-hit deformation technique for interpass holding of 5 and 20s. The present study focuses on the effect of prestrain and deformation temperature on recrystallisation behaviour of the investigated steel. The fractional softening was calculated based on the percentage difference between the areas under the interrupted and uninterrupted deformations flow curves. The T5% and T95%, marking the beginning and end of recrystallisation, respectively, are determined as a function of strain. Quantitative microstructural studies validated the findings from the softening studies. The predicated results of recrystallisation regime are found to be in agreement with industrial observation and other experimental measurement for this steel. It can be seen that the dilute additions of Nb can influence the static recrystallisation of austenite under certain rolling condition which may lead to improved mechanical properties of steel

Microstructural evaluation in structural steels containing dilute niobium concentrations

The thermomechanical processing of microalloyed steels has been instrumental in the successful development of HSLA steel plate and strip products with enhanced property combinations. Microalloying additions of niobium (Nb) have the most potent effect in retarding the static recrystallisation of austenite during interpass times by solute drag and precipitate pinning mechanism. However, published research on the use of Nb in carbon steel long products (C > 0.20 wt.%) is somewhat limited due to the low solubility of Nb in austenite at such carbon levels. Such steels represent well over 50 % of overall world steel consumption primarily intended for the construction sector and therefore represent an essential area for cost efficiencies. This research aimed to understand the influence of dilute niobium concentrations (50-200 ppm) on microstructural evaluation in structural steels. The investigation involved three low carbon steels with varying Nb concentration at constant C (0.20%) and N (0.007%) levels. Isothermal double-hit deformation technique led to the determination of T5% and T95% (beginning and end of recrystallisation, respectively) as a function of strain and interpass time. The results indicate that the T5% increases with increasing Nb supersaturation in austenite at a rate of 40°C per 0.006% Nb supersaturation for a true stain ε=0.40. The Nb supersaturation ratio ≥ 6 resulted in an unrecrystallised microstructure at respective T5% for all tested steels. A high, localised strain-induced precipitation of Nb(CN) was observed at the austenite subgrain boundaries. This translated into higher values for local precipitate pinning force (FPIN), which were significantly higher than one predicted from equilibrium thermodynamics. The critical FPIN for retardation of static recrystallisation was found to be 1.8 MPa at respective T5% for each steel. The present study has contributed to advancing our knowledge of the interplay between solute supersaturation and volume fraction of Nb(CN) precipitation. Even the lowest addition of 66 ppm Nb could retard the recrystallisation at certain rolling conditions and raised T5% temperature over base steel composition. It is possible to develop a viable TMCP deformation schedule to best benefit from dilute Nb additions. The better control of austenite microstructure will improve the mechanical properties of existing low value-added products through ferrite grain refinement. The dilute Nb additions might permit the reduction in other substitutional alloying elements such as Mn as the Nb provides a more strengthening effect at low cost

The Use of Extreme Risk Protection Orders Intended to Prevent Mass Violence in Oregon: A Descriptive Study

Purpose: Firearm violence is a critical public health issue in the United States. Extreme Risk Protection Order (ERPO) laws are an intervention method that have been enacted in many states to prevent firearm violence including mass violence threats. This study examined the characteristics of ERPO petitions filed in Oregon for a 6-year period that involved mass violence threats. Method: ERPO petitions included in court records obtained through the Oregon Judicial Case Information Network, from January 1, 2018, to December 31, 2023 were abstracted; a 20% random sample of records was double-coded to ensure interrater reliability. An epidemiologic analysis of cases involving threats of mass violence was conducted by comparing the characteristics and outcomes of those cases to cases involving other types of firearm violence threats. Results: Data analyzed from January 1, 2018, to December 31, 2022 showed there were 649 ERPO petitions filed and 506 (78%) were initially granted. There were 72 petitions that cited risk of mass violence and 67 (93%) were initially granted. There were 24 petitions that cited a risk to schools or college campuses, and all 24 (100%) were initially granted. Ongoing analyses will examine the characteristics of petitions citing threats of mass violence compared to petitions that cited other types of threats. Conclusion: Oregon’s ERPO law is being used to address firearm injury risk, including mass violence risk and risk to schools and college campuses. This effort will inform efforts to improve implementation of the ERPO law in Oregon for threats of mass violence

Optimizing Treatment Strategies in a Pediatric Infectious Case: A Multidisciplinary Perspective

This case study presents the comprehensive evaluation and management of a 4-year-old male patient with phimosis who presented with fever, anorexia, weakness, and burning micturition. Upon admission, bilateral multiple renal abscesses and cystitis were diagnosed through ultrasound examination, prompting initiation of intravenous (IV) piperacillin–tazobactam combination and IV vancomycin. Due to concerns of red man syndrome, vancomycin was closely monitored, and a multidisciplinary approach involving specialists in pediatric infectious diseases and surgery was adopted. Sensitivity testing revealed Escherichia coli infection resistant to multiple antibiotics, leading to a switch to IV meropenem. Additional investigations for suspected mumps yielded negative results, emphasizing the importance of thorough evaluation. The patient’s condition improved with appropriate antibiotic therapy, as evidenced by decreasing abscess size and resolution of symptoms. This case underscores the significance of tailored antibiotic therapy, close monitoring, and multidisciplinary collaboration in managing complex pediatric infectious cases, ensuring optimal patient outcomes. Additionally, the patient’s complete vaccination highlights the potential for atypical mumps presentations. Resurgence factors include secondary vaccine failure, reduced vaccine effectiveness (85–90%), and lack of natural boosting from wild-type virus

Mutation of SIVA, a candidate metastasis gene identified from clonally related bilateral breast cancers, promotes breast cancer cell spread in vitro and in vivo.

Metastasis is the most dreaded outcome after a breast cancer diagnosis, and little is known regarding what triggers or promotes breast cancer to spread distally, or how to prevent or eradicate metastasis effectively. Bilateral breast cancers are an uncommon form of breast cancers. In our study, a percentage of bilateral breast cancers were clonally related based on copy number variation profiling. Whole exome sequencing and comparative sequence analysis revealed that a limited number of somatic mutations were acquired in this breast-to-breast metastasis that might promote breast cancer distant spread. One somatic mutation acquired was SIVA-D160N that displayed pro-metastatic phenotypes in vivo and in vitro. Over-expression of SIVA-D160N promoted migration and invasion of human MB-MDA-231 breast cancer cells in vitro, consistent with a dominant negative interfering function. When introduced via tail vein injection, 231 cells over-expressing SIVA-D160N displayed enhanced distant spread on IVIS imaging. Over-expression of SIVA-D160N promoted invasion and anchorage independent growth of mouse 4T1 breast cancer cells in vitro. When introduced orthotopically via mammary fat pad injection in syngeneic Balb/c mice, over-expression of SIVA-D160N in 4T1 cells increased orthotopically implanted mammary gland tumor growth as well as liver metastasis. Clonally related bilateral breast cancers represented a novel system to investigate metastasis and revealed a role of SIVA-D160N in breast cancer metastasis. Further characterization and understanding of SIVA function, and that of its interacting proteins, may elucidate mechanisms of breast cancer metastasis, providing clinically useful biomarkers and therapeutic targets

On the Synergistic Catalytic Properties of Bimetallic Mesoporous Materials Containing Aluminum and Zirconium: The Prins Cyclisation of Citronellal

Bimetallic three-dimensional amorphous mesoporous materials, Al-Zr-TUD-1 materials, were synthesised by using a surfactant-free, one-pot procedure employing triethanolamine (TEA) as a complexing reagent. The amount of aluminium and zirconium was varied in order to study the effect of these metals on the Brønsted and Lewis acidity, as well as on the resulting catalytic activity of the material. The materials were characterised by various techniques, including elemental analysis, X-ray diffraction, high-resolution TEM, N2 physisorption, temperature-programmed desorption (TPD) of NH3, and 27Al MAS NMR, XPS and FT-IR spectroscopy using pyridine and CO as probe molecules. Al-Zr-TUD-1 materials are mesoporous with surface areas ranging from 700–900 m2 g−1, an average pore size of around 4 nm and a pore volume of around 0.70 cm3 g−1. The synthesised Al-Zr-TUD-1 materials were tested as catalyst materials in the Lewis acid catalysed Meerwein–Ponndorf–Verley reduction of 4-tert-butylcyclohexanone, the intermolecular Prins synthesis of nopol and in the intramolecular Prins cyclisation of citronellal. Although Al-Zr-TUD-1 catalysts possess a lower amount of acid sites than their monometallic counterparts, according to TPD of NH3, these materials outperformed those of the monometallic Al-TUD-1 as well as Zr-TUD-1 in the Prins cyclisation of citronellal. This proves the existence of synergistic properties of Al-Zr-TUD-1. Due to the intramolecular nature of the Prins cyclisation of citronellal, the hydrophilic surface of the catalyst as well as the presence of both Brønsted and Lewis acid sites synergy could be obtained with bimetallic Al-Zr-TUD-1. Besides spectroscopic investigation of the active sites of the catalyst material a thorough testing of the catalyst in different types of reactions is crucial in identifying its specific active sites