bluuebunny/crossref_metadata_2025 huggingface dataset:
Placentа of BCG‐Vaccinated Women in early Pregnancy is Colonized with Non‐Immunogenic Mycobacterial L‐forms
Authors: Dimova Tanya , Dimitrova Violeta , Grozdanov Petar , Markova Nadya
Published: November 2022

Problem

Long‐lived mycobacterial L‐forms (mL‐forms) could be detected in the blood of BCG‐vaccinated people. We have previously found mL‐forms in term placentas and blood of neonates, delivered by healthy BCG‐vaccinated mothers as first formal demonstration that BCG vaccination in the childhood of the woman could affect her placentobiome during pregnancy. Of note, the isolated mL‐forms reverted to the cell‐walled state of the parental BCG bacilli in vitro.

Method of study

Here, we analyzed triple samples of blood, decidua and chorion taken from BCG‐vaccinated pregnant women, directed to elective abortions (6‐12 gestation weeks). The colonization of the primary samples with mycobacterial L‐forms (mL‐forms) was evaluated using microbiological isolation and subsequent identification by real time PCR and morphological characterization by light microscopy and SEM. The potential of early placenta‐derived mL‐forms to expand mycobacteria‐reactive γδ T cells in vitro was assessed using FACS, whereas their immunogenicity in vivo was followed up after i.p. inoculation in rats.

Results

Our results showed two important findings: 1) viable filterable mL‐forms varying in size, shape and proliferation modes are capable of colonizing the gestational tissues of BCG‐vaccinated women early in pregnancy and 2) early placenta‐derived mL‐forms are not as immunogenic as walled M. bovis BCG bacilli, shown by lack of stimulation of mycobacteria‐reactive γδ T cells co‐cultured with early placenta‐derived mL‐forms and inefficient internalization of mL‐forms by rat's peritoneal phagocytes in vivo.

Conclusion

Although generally thought to be reduced in virulence, mL‐forms could provide a reservoir, hidden from the immune system especially in an immune privileged niche like placenta.
Impaired pulmonary function mediates inattention in young adults born extremely preterm
Authors: Litt Jonathan S. , Johnson Samantha , Marlow Neil , Tiemeier Henning
Published: November 2022

Aim

To test whether poor childhood pulmonary function explains the relationship between extremely preterm (EP) birth and attention‐deficit/hyperactivity disorder (ADHD) symptoms in young adulthood.

Methods

EPICure birth cohort participants include children born <26 weeks' gestation in the United Kingdom and Ireland in 1995 and their term‐born classmates. Predictor was EP birth. Outcomes were inattention/hyperactivity subscale z‐scores at 19 years. Forced expiratory volume (FEV1) z‐scores in childhood and young adulthood were mediators. We used recursive path analysis to determine the direct effect of EP birth on inattention/hyperactivity and its indirect effect through pulmonary function.

Results

Ninety EP and 47 term‐born participants had pulmonary function testing at 11 and 19 years. Inattention z‐scores were higher in the EP group (mean difference 0.55 [95% CI 0.11, 0.99]) but not hyperactivity. Compared to term‐born peers, EP participants had lower FEV1 z‐scores at 11 (mean difference−1.35 [95% CI −1.72, −0.98]) and 19 (mean difference−1.29 [95% CI −1.65, −0.92]). Path models revealed that childhood pulmonary function explained the relationship between EP birth and inattention.

Conclusions

Extremely preterm young adults have increased risk for inattention compared to term‐born peers. Poor pulmonary function appears to underlie this risk. The mechanisms responsible remain unclear and warrant further study.
Radiological incidence of donor‐site incisional hernia and parastomal hernia after vertical rectus abdominus myocutaneous flap‐based reconstruction following colorectal surgery
Authors: Tang Alethea M. , Spencer Naomi , Parkins Kristie , Bevan Victoria , Taylor Gregory , Markham Derrian , Drew Peter , Harries Rhiannon L.
Published: November 2022

Aim

A vertical rectus abdominis myocutaneous (VRAM) flap is commonly used to reconstruct perineal defects for low rectal and anal cancer. The incidence of midline incisional hernias after VRAM reconstruction varies from 3.6% when detected clinically to 50% when detected radiologically. The aim of this study is to accurately determine the radiological incidence of donor‐site incisional and parastomal hernia following VRAM reconstruction.

Method

This was a retrospective cohort study of patients undergoing colorectal surgery requiring VRAM reconstruction over 10 years. Data were collected on patient demographics, indication for surgery and surgical procedure, including details of any hernia repair. Images from surveillance CTs were reviewed for the presence and size of midline incisional and/or parastomal hernias. Parastomal hernias were classified based on the European Hernia Society (EHS) classification.

Results

One hundred and seventy three patients were included in the analysis. The median age was 67 years (range 29–88 years) and the median length of follow‐up was 49 months (interquartile range 24.3–71.0 months). The cumulative incidence of donor‐site incisional hernia after VRAM at 1, 2 and 5 years was 15.1%, 25.4% and 29.1%, respectively. The cumulative incidence for PSH at 1, 2 and 5 years was 33.1%, 46.6% and 53.3%, respectively (95% CI 45.4%–60.5%).

Conclusion

Most patients who develop donor‐site incisional hernia and parastomal herniation following VRAM tend to do so within the first 2 years. Although the use of CT imaging improves the diagnosis of donor‐site incisional and parastomal hernias, the clinical significance of this is unknown.
Evolutionary double suicide in symbiotic systems
Authors: Uchiumi Yu , Sato Masato , Sasaki Akira
Published: November 2022

Mutualism is thought to face a threat of coextinction cascade because the loss of a member species could lead to the extinction of the other member. Despite this common emphasis on the perils of such knock‐on effect, hitherto, the evolutionary causes leading to extinction have been less emphasised. Here, we examine how extinction could be triggered in mutualism and whether an evolutionary response to partner loss could prevent collateral extinctions, by theoretically examining the coevolution of the host exploitation by symbionts and host dependence on symbiosis. Our model reveals that mutualism is more vulnerable to co‐extinction through adaptive evolution (evolutionary double suicide) than parasitism. Additionally, it shows that the risk of evolutionary double suicide rarely promotes the backward evolution to an autonomous (non‐symbiotic) state. Our results provide a new perspective on the evolutionary fragility of mutualism and the rarity of observed evolutionary transitions from mutualism to parasitism.
A question to the physician from a patient on hemodialysis: Would it be safe to run a marathon? A case report
Authors: Kaarup Sophie , Hansen Henrik P. , Lindhard Kristine
Published: November 2022

A patient on maintenance hemodialysis asked his physician if it would be safe for him to run a marathon. For healthy persons, studies show that it is relatively safe. Very few data are available on patients on hemodialysis performing out of center endurance exercise. To address this question, we conducted a clinical study to investigate the electrolyte derangements during different running distances. Our main concern was development of hyperkalemia. We present a case of an anuric hemodialysis patient, who ran eight different runs with a maximum distance of 32.2 km. Blood was analyzed before and after the runs. We did not find severe hyperkalemia at any point. According to this study, we found no signs of increased risk.
High levels of risk factors and poor secondary prevention for coronary heart disease patients in public hospitals: A descriptive repeated measures study
Authors: Al‐Smadi Ahmed Mohammad , Ashour Ala Fawzi , Fitzsimons Donna , Slater Paul , O'Neill Brenda , Ajlouni Wisal , Shajrawi Abedalmajeed Methqal
Published: November 2022

Background

Secondary prevention is a priority after coronary revascularization for effective long‐term cardiovascular care. Coronary Heart Disease is a major health problem in Jordan, but little is known about the current provision of secondary prevention.

Aim

The aim of this study was to evaluate risk factors and explore the current provision of secondary Coronary Heart Disease prevention among patients presenting with first‐time Coronary Heart Disease at two time points: during hospitalization (Time 1) and 6 months later (Time 2), in multicentre settings in Jordan.

Methods

A descriptive, repeated measures research study design was applied to a consecutive sample of 180 patients with first‐time Coronary Heart Disease. Demographic and clinical details were recorded from medical files. Self‐administered questionnaires developed by the researchers were used to measure secondary prevention information related to Coronary Heart Disease, including secondary prevention services, lifestyle advice received and medical advice topics. A short form of the International Physical Activity Questionnaire was used to measure physical activity. Participants were assessed at Times 1 and 2.

Results

Unstructured lifestyle advice given to the patients at Times 1 and 2 most frequently related to medications, smoking, diet and blood lipids control advice topics, with no statistically significant improvement in cardiovascular risk factors among patients between Times 1 and 2.

Conclusion

Despite an extremely high prevalence of risk factors in this population, the provision of secondary prevention is poor in Jordan, which requires urgent improvement, and the contribution of nurses' to secondary prevention should be enhanced.
Neutrophils as immune effector cells in antibody therapy in cancer
Authors: Behrens Leonie M. , van Egmond Marjolein , van den Berg Timo K.
Published: November 2022

Tumor‐targeting monoclonal antibodies are available for a number of cancer cell types (over)expressing the corresponding tumor antigens. Such antibodies can limit tumor progression by different mechanisms, including direct growth inhibition and immune‐mediated mechanisms, in particular complement‐dependent cytotoxicity, antibody‐dependent cellular phagocytosis, and antibody‐dependent cellular cytotoxicity (ADCC). ADCC can be mediated by various types of immune cells, including neutrophils, the most abundant leukocyte in circulation. Neutrophils express a number of Fc receptors, including Fcγ‐ and Fcα‐receptors, and can therefore kill tumor cells opsonized with either IgG or IgA antibodies. In recent years, important insights have been obtained with respect to the mechanism(s) by which neutrophils engage and kill antibody‐opsonized cancer cells and these findings are reviewed here. In addition, we consider a number of additional ways in which neutrophils may affect cancer progression, in particular by regulating adaptive anti‐cancer immunity.
Platelet‐rich fibrin combined with a particulate bone substitute versus guided bone regeneration in the damaged extraction socket: An in vivo study
Authors: Park Jin‐Young , Hong Kyu‐Jin , Ko Kyung‐A , Cha Jae‐Kook , Gruber Reinhard , Lee Jung‐Seok
Published: November 2022

Aim

It has been proposed that platelet‐rich fibrin (PRF) can be used to support bone regeneration during alveolar ridge augmentation. The aim of this study was to determine whether an approach utilizing PRF provides similar performance to the established guided bone regeneration (GBR) procedure.

Materials and Methods

Two‐wall defects were surgically created in beagle dogs and treated in three experimental groups: (i) a sticky bone (SB) substitute prepared using liquid PRF and deproteinized porcine bone mineral (DPBM); (ii) SB covered with solid PRF compressed into a membrane; and (iii) GBR performed using DPBM covered by a collagen membrane. Quantitative reverse‐transcription polymerase chain reaction was applied to the specimen after 1 week of healing, and microcomputed tomography (micro‐CT) and histological outcomes were analysed after 8 weeks of healing.

Results

Compared with GBR, PRF resulted in a moderate increase in the expression levels of osteoblast and osteoclast markers, osteocalcin, and calcitonin receptor. Moreover, PRF modestly increased angiogenesis and the inflammation markers vascular endothelial growth factor (VEGF) and IL‐6. Micro‐CT and histological analyses confirmed the expected increased alveolar ridge area, with no significant differences between the three groups. Consistently, graft consolidation, as indicated by new bone formation at the defect site, did not differ significantly between groups.

Conclusions

The present results demonstrate that PRF‐based approaches perform comparably to the established GBR procedure in terms of the consolidation of DPBM in two‐wall alveolar defects.
Immigrant parents and children navigating two languages: A scoping review
Authors: deSouza Darcey K. , Lin Hua , Cox Ronald B.
Published: November 2022

Upon initiating school, immigrant children begin to lose much of their heritage language (HL) abilities, resulting in the erosion of a common shared language with their parents. Although communication is fundamental to positive parent–child relationships, research on the effects of navigating two languages is missing from most family theories regarding immigrant populations. This scoping review provides a comprehensive overview of the literatures from family science, child development, communication, and applied linguistics regarding how immigrant families navigate the adoption of a host country's language and the maintenance of their HL, and how this process impacts parent–child relationships. Results indicate that (a) the literature is relatively small and underdeveloped; (b) there is a limiting focus on individual language proficiency rather than a dyadic or familial communicative process; and (c) child HL proficiency is strongly correlated with healthier parent–child relationships and child outcomes. Limitations and future directions are discussed.
Phosphorus fractions in leaves
Authors: Suriyagoda Lalith D. B. , Ryan Megan H. , Gille Clément E. , Dayrell Roberta L. C. , Finnegan Patrick M. , Ranathunge Kosala , Nicol Dion , Lambers Hans
Published: November 2022

Leaf phosphorus (P) comprises four major fractions: inorganic phosphate (Pi), nucleic acids, phospholipids, P‐containing metabolites and a residual fraction. In this review paper, we investigated whether allocation of P fractions varies among groups of terrestrial vascular plants, and is indicative of a species' strategy to use P efficiently. We found that as leaf total P concentration increases, the Pi fraction increases the most, without a plateau, while other fractions plateau. Variability of the concentrations of leaf P fractions is greatest among families > species(family) > regions > plant life forms. The percentage of total P allocated to nucleic acid‐P (20–35%) and lipid‐P (14–34%) varies less among families/species. High photosynthetic P‐use efficiency is associated with low concentrations of all P fractions, and preferential allocation of P to metabolite‐P and mesophyll cells. Sequential resorption of P from senescing leaves starts with Pi, followed by metabolite‐P, and then other organic P fractions. Allocation of P to leaf P fractions varies with season. Leaf phytate concentrations vary considerably among species, associated with variation in photosynthesis and defence. Plasticity of P allocation to its fractions is important for acclimation to low soil P availability, and species‐specific P allocation is needed for co‐occurrence with other species.
Transplastomic tomatoes expressing double‐stranded RNA against a conserved gene are efficiently protected from multiple spider mites
Authors: Wu Mengting , Zhang Qi , Dong Yi , Wang Zican , Zhan Wenqin , Ke Zebin , Li Shengchun , He Lin , Ruf Stephanie , Bock Ralph , Zhang Jiang
Published: November 2022

Spider mites are serious pests and have evolved significant resistance to many chemical pesticides, thus making their control challenging. Several insect pests can be combated by plastid‐mediated RNA interference (PM‐RNAi), but whether PM‐RNAi can be utilized to control noninsect pests is unknown.

Here, we show that three species of spider mites (Tetranychus evansi, Tetranychus truncatus, and Tetranychus cinnabarinus) take up plastid RNA upon feeding. We generated transplastomic tomato plants expressing double‐stranded RNA (dsRNA) targeted against a conserved region of the spider mite β‐Actin mRNA.

Transplastomic plants exhibited high levels of resistance to all three spider mite species, as evidenced by increased mortality and suppression of target gene expression. Notably, transplastomic plants induced a more robust RNAi response, caused higher mortality, and were overall better protected from spider mites than dsRNA‐expressing nuclear transgenic plants.

Our data demonstrate the potential of PM‐RNAi as an efficient pest control measure for spider mites and extend the application range of the technology to noninsect pests.
Far‐UVC Light at 222 nm is Showing Significant Potential to Safely and Efficiently Inactivate Airborne Pathogens in Occupied Indoor Locations
Authors: Brenner David J.
Published: November 2022

Far UVC light (UVC wavelengths below 235 nm) is a comparatively new modality with significant potential to safely and very efficiently inactivate airborne pathogens in occupied indoor locations. There are now significant accumulations of evidence both in terms of the safety of far‐UVC for direct exposure of occupied indoor locations, and in terms of its efficacy to markedly reduce the levels of active airborne pathogens This article reviews both the safety of far‐UVC, which has a clear mechanistic underpinning, and its efficacy, both in the laboratory and in full‐sized rooms. Highlighted is the paper by Ma et al. in this issue of Photochemistry and Photobiology which addresses the efficacy of far‐UVC light (in this case at 222 nm) against a broad spectrum of common pathogens including SARS‐CoV‐2 and influenza viruses. From their data, and based on our understanding of the largely random nature of UVC‐induced damage within the genome, far UVC would be expected to be effective against the next pandemic virus, if and when it emerges.
Early mortality among aboriginal and non‐aboriginal women who had a preterm birth in Western Australia: A population‐based cohort study
Authors: Bailey Helen D. , Gray Caitlin , Adane Akilew A. , Strobel Natalie A. , White Scott W. , Marriott Rhonda , Tessema Gizachew A. , Shepherd Carrington C. J. , Sharp Mary
Published: November 2022

Background

Having a preterm (<37 weeks' gestation) birth may increase a woman's risk of early mortality. Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have higher preterm birth and mortality rates compared with other Australian women.

Objectives

We investigated whether a history of having a preterm birth was associated with early mortality in women and whether these associations differed by Aboriginal status.

Methods

This retrospective cohort study used population‐based perinatal records of women who had a singleton birth between 1980 and 2015 in Western Australia linked to Death Registry data until June 2018. The primary and secondary outcomes were all‐cause and cause‐specific mortality respectively. After stratification by Aboriginal status, rate differences were calculated, and Cox proportional hazard regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for all‐cause and cause‐specific mortality.

Results

There were 20,244 Aboriginal mothers (1349 deaths) and 457,357 non‐Aboriginal mothers (7646 deaths) with 8.6 million person‐years of follow‐up. The all‐cause mortality rates for Aboriginal mothers who had preterm births and term births were 529.5 and 344.0 (rate difference 185.5, 95% CI 135.5, 238.5) per 100,000 person‐years respectively. Among non‐Aboriginal mothers, the corresponding figures were 125.5 and 88.6 (rate difference 37.0, 95% CI 29.4, 44.9) per 100,000 person‐years. The HR for all‐cause mortality for Aboriginal and non‐Aboriginal mothers associated with preterm birth were 1.48 (95% CI 1.32, 1.66) and 1.35 (95% CI 1.26, 1.44), respectively, compared with term birth. Compared with mothers who had term births, mothers of preterm births had higher relative risks of mortality from diabetes, cardiovascular, digestive and external causes.

Conclusions

Both Aboriginal and non‐Aboriginal women who had a preterm birth had a moderately increased risk of mortality up to 38 years after the birth, reinforcing the importance of primary prevention and ongoing screening.
The impact of emotional facial expressions on reflexive attention depends on the aim of dynamic gaze changes: An ERP study
Authors: Bagherzadeh‐Azbari Shadi , Lion Charlotte J. , Stephani Tilman , Dimigen Olaf , Sommer Werner
Published: November 2022

The emotional expression and gaze direction of a face are important cues for human social interactions. However, the interplay of these factors and their neural correlates are only partially understood. In the current study, we investigated ERP correlates of gaze and emotion processing following the initial presentation of faces with different emotional expressions (happy, neutral, angry) and an averted or direct gaze direction as well as following a subsequent change in gaze direction that occurred in half of the trials. We focused on the time course and scalp topography of the N170 and EPN components. The N170 amplitude was larger to averted than direct gaze for the initial face presentation and larger to gaze changes from direct to averted than from averted to direct in response to the gaze change. For the EPN component in response to the initial face presentation, we replicate classic effects of emotion, which did not interact with gaze direction. As a major new finding, changes from direct to averted gaze elicited an EPN‐like effect when the face showed a happy expression. No such effect was seen for angry expressions. We conclude that happy faces reflexively attract attention when they look at the observer rather than away from the observer. These results for happy expressions are in line with the shared signal hypothesis that posits a better processing of expressions if their approach or avoidance tendency is consistent with gaze direction. However, the shared signal hypothesis is not supported by the present results for angry faces.
Collective parent action: A review of motivations, experiences, and social transformations
Authors: Cossyleon Jennifer E. , Geller Joanna
Published: November 2022

Parents—caregivers of children and other kin—often become involved in collective action because they see a need for change, and because it is part of their practice of caring and thriving. This review traces the mobilization of mothers and caregivers working on progressive community organizing campaigns, what we callcollective parent action. We center the experiences of socially marginalized groups and focus on three main areas of inquiry: (1) why caregivers, largely mothers of color, become involved in collective action; (2) what constraints and supports their involvement; and (3) how their involvement shapes them and their families. We end with three main directions for future research and a call for studies to continue to explore the interconnections of gender, family, and collective action.
The Green Elephants in the Room: Perceived Environmental Harm and Support for Regulation Among Republicans
Authors: Dacey Timothy , Stewart Evan
Published: November 2022

Previous research identifies a “great paradox” in attitudes toward environmental regulation: some people close to environmental risk nevertheless oppose environmental regulation for partisan reasons. Does this pattern hold in large survey samples? Unexpectedly, we do not find evidence for it. Instead, we find that Republicans who report higher levels of personal environmental harm also report stronger support for environmental regulation. This pattern holds across varied measurement specifications, and it is weaker for Democrats, suggesting that exposure to environmental harm might directly challenge and change partisan opposition to environmental reform. We present a theory and research agenda that accounts for these “green elephants in the room.” Our work, as we will demonstrate, crosses at least three disciplinary boundaries: social psychology, cultural sociology, and political science. A conceptual replication of results is provided in the Appendices S1 and S2.
Comparison of European recommendations about patient blood management in postpartum haemorrhage
Authors: Leal Rosa , Lança Filipa
Published: November 2022

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality and morbidity worldwide. Some documents with practical recommendations for the management of PPH do not include the most updated directives. This review offers a quality comparison of the recommendations stated in Europe since 2015. A literature search was conducted to identify the documents published in Europe from 2015 to 2020 containing recommendations about management of PPH. The search returned 10 publications. A narrative synthesis and a summary of the information about PPH definition and its management were performed. Differences in the definition of PPH were identified: some documents considered the delivery procedure, and many publications included severity criteria. The therapeutic goal for red blood cells transfusion ranged from 6 to 9 g/dl. There were divergences in the need for considering haemostatic results before fresh frozen plasma transfusion. The therapeutic goal of platelet transfusion ranged from 50 x 109 to 100 x 109 μ/L. There was a wide consensus about the therapeutic goal of fibrinogen replacement (>2 g/L), but not about its use in an unmonitored or pre‐emptive manner. Most publications included therapeutic approaches such as tranexamic acid and recombinant factor VII activated, but not prothrombin complex concentrate or coagulation factor XIII. The recommendations about PPH management offered in European documents are heterogeneous and have changed over time. The standardisation of all them could be useful to make progress in PPH clinical management and research which, in turn, could strongly impact in patient outcomes.
How do we assess batch‐to‐batch consistency between extracellular vesicle products?
Authors: Korchak Jennifer A. , Wiest Elani F. , Zubair Abba C.
Published: November 2022

Background

Extracellular vesicles (EVs) have gained interest in the field of regenerative and transfusion medicine. Specifically, current Good Manufacturing Practice (cGMP)‐grade EVs produced by mesenchymal stromal cells (MSCs) are an intriguing option for cell‐free therapeutics. With the development of cGMP‐grade EV products, a simple and reliable method for batch‐to‐batch consistency is needed.

Study Design and Methods

The objective of this study was to validate a method to semiquantitatively assess the batch‐to‐batch consistency of isolated EVs. A multiplex bead‐based flow cytometric assay containing 37 surface markers and 2 assay control antibody‐coated capture beads was validated. Detection limits (n = 10 buffer samples), repeatability (n = 9 EV samples), and intra‐observer reproducibility over 2 days (n = 10 EV batches) were assessed. A Spearman correlation matrix was used to evaluate the batch‐to‐batch consistency of independently isolated EV products (n = 37 surface markers). Batches with a Spearman correlation coefficient ≥0.9 and p < 0.05 were considered statistically indistinguishable from previous batches.

Results

This assay demonstrated robust repeatability as well as intra‐ and inter‐assay reproducibility. In‐house batches of EVs were significantly correlated (r ≥ 0.90; p ≤ 1×10−14). Compared with buffer, EV batches had correlation coefficients near zero (r ≤ −0.10; p ≥ 0.12). Commercially sourced EVs significantly correlated with in‐house EV batches, but fell below the 90% correlation cutoff (r ≤ 0.71; p ≤ 0.0004).

Discussion

This time‐efficient and technically simple assay offers a robust method of quality control for assessing the batch‐to‐batch reproducibility of cGMP‐grade EV products.
"Fuga con Pajarillo"
Authors: Rincón Suárez Liz Johana
Published: November 2022

Este artículo tiene como objetivo comprender la experiencia y las trayectorias de migración de mujeres venezolanas asentadas de manera transitoria en la ciudad de Cali, Colombia. Parte de la pregunta: ¿cómo mujeres venezolanas en tránsito significan la experiencia migratoria y en qué medida dichos significados articulan procesos de agencia y de ejercicio de derechos? Los datos presentados son el resultado de un ejercicio etnográfico con treinta familias caminantes en el campamento de refugiados del terminal y caminantes en la Vía Panamericana en Cali, y de cinco entrevistas en profundidad realizadas a mujeres entre los 23 y 36 años. Los resultados se analizaron a la luz de los enfoques teórico-críticos de las migraciones que vinculan los conceptos de trayectoria, migración pendular y mundos de la vida cotidiana. La conclusión final del análisis considera que la migración en tránsito es una experiencia que expresa múltiples violencias para las mujeres, pero al mismo tiempo produce confrontaciones en los significados y prácticas culturales. Estas confrontaciones devienen en nuevas subjetividades que impactan los universos de sentido de la sociedad de origen y de acogida. Las trayectorias de las caminantes dan cuenta de la necesidad de comprender la migración de tránsito como migración de refugio, lo cual implica la construcción de una política migratoria que supere las miradas Estado-céntricas sobre la ciudadanía.
Analysis of the Load Bearing Capacity of Cracked Additively Manufactured Polymers Using Failure Assessment Diagrams
Authors: Cicero Sergio , Martínez-Mata Víctor , Arrieta Sergio
Published: November 2022

Failure Assessment Diagrams (FADs) are, in practice, the main engineering tool for the analysis of structural components containing cracks. They are utilised in well-known structural integrity assessment procedures, such as BS7910 and API 579 1/ASME FFS 1, and their reliability has been proven by numerous laboratory tests and industrial applications. However, they have been defined and validated in metallic materials, so their application in other types of materials requires demonstrating that the different assumptions taken when analysing metals are also valid for the particular material (non-metallic) being analysed.

At the same time, additive manufacturing (AM) is a growing technology that allows complex geometries to be fabricated through a quite simple process. Among the different AM techniques, fused deposition modelling (FDM) is one of the most widely used, and consists in the extrusion of heated feedstock plastic filaments through a nozzle tip. The resulting printed materials have quite specific characteristics and properties, which are highly dependent on the printing parameters (e.g., raster orientation, printing temperature, etc.) and on the resulting state of internal defects.

This paper provides FAD analyses for two additively manufactured (FDM) polymers: ABS and PLA. The results show that the FAD methodology may be applied for these two particular polymers, as long as linear-elastic fracture toughness values are used.
Criteria for Specifying Static Equipment Construction Code for Process Plant
Authors: Chikhaliya Kamlesh , Gawlick Ruediger
Published: November 2022

Capital costs of static equipment including pressure vessels, heat exchangers and process columns contribute approx. 20 to 40% of cost of total plant. Static equipment is being designed and manufactured based on international codes, standards and statutory legal requirements. Selection of appropriate equipment construction code fulfilling ambient conditions, equipment design temperatures and country specific regulations has significant implications on cost effectiveness and required safety of process plant. This paper presents basic criteria for selection of ASME Sec. VIII or EN-13445 for equipment design and construction based on design temperature, ambient conditions and country specific legal requirements like PED 2014/68/EU and TRCU 032/2013. Effect of change of elevated temperature and material on weight of equipment is also demonstrated by example. Material selection based on corrosion aspects is not included in this paper.
CFD Study of Cooking Liquor Blow for Piping Thrust Force and Risk of Condensation Hydraulic Shock
Authors: Carlson Andrew , Narayanan Chidambaram , Lakehal Djamel , Hermonen Timo , Jokinen Noora , Ikävalko Juho
Published: November 2022

This study is an interesting industrial case study for the application of a validated flashing and hydraulic shock modelling approach to the safety and design of a reactor blow line. The maximum flow rate is important for sizing of downstream components. The high pressure of the blow and flashing of the liquid can result in significant forces on pipe bends and other geometrical features. Analysis and prediction of such forces are of importance for the structural design and anchoring of the piping. Another concern for a liquid blow under high pressure is the potential for condensation-induced hydraulic shock. The collapse of the flashed vapor to the liquid phase creating shock waves of large amplitudes is a serious safety concern.

The CFD model used the homogeneous mixture model with a flashing model for phase change of the fluid. The properties of the fluid were defined by a custom function which interpolated between tabulated values of the thermodynamic and transport properties. The CFD simulations confirmed the risk of condensation hydraulic shock when the blow down is initiated with empty pipes and also demonstrated that a hydraulic shock could be prevented with liquid-filled condition. The pipework geometry was also optimized to reduce the forces acting at the junctions. The vapour quality at the outlet as a result of flashing was estimated which is necessary for the design of downstream systems.
Practical Methodology of Multiaxial Dynamic Strain Measurement and Stress Calculation for Fatigue Evaluation of Small Bore Connection Due to Vibration
Authors: Takahama Tsunemichi
Published: November 2022

This study presents that the methodology of fatigue evaluation of small bore connection (SBC), which includes strain measurement, stress calculation, and life estimation. This methodology was used in actual fields and has been confirmed to be so practical that it satisfies the following conditions.

A. Multiaxial dynamic strains required for the calculation of the combined stresses can be measured.

B. The fatigue life prediction can be calculated from the measurement data. Specifically, the most critical accumulated fatigue damage value and direction are calculated by repeatedly extracting a stress-time history and counting cycles.

C. Either in bending or torsional stress dominant vibration, or in different size piping vibration, the same spread sheet can be used to calculate the dynamic stress and evaluate the fatigue.

D. What is necessary to prepare in advance is a suitable fatigue curve, Young’s modulus, and Poisson’s ratio only. The evaluation can be done by simply pasting the measured strain data obtained in the field into a spreadsheet. There is no need for any other preparation such as model calculation or parameter correlation.

E. The calculation can be done in a short time (less than 6 hours) with relatively inexpensive hardware and software (about $3,000 together).
Predicting the Projectile Velocity of a Two-Stage Gas Gun Using Machine Learning
Authors: Shojaei Pouya , Trabia Mohamed , O’Toole Brendan , Jennings Richard
Published: November 2022

Two-stage light gas guns are used to accelerate projectiles to velocities of multiple kilometers per second. These guns are used in many applications including experiments to understand the response of structural components within spacecraft and satellites to impacts of orbital debris. Obtaining a precise projectile velocity can be challenging due to the many uncertainties associated with these guns. Therefore, most gas guns depend on the expertise of operators to estimate the mass of projectile, mass of main charge, the propellent gas type, the piston mass, and the pump tube (PT) pressure that would yield a specific projectile velocity. These uncertainties lead to the current need for multiple and costly gas gun experiments to achieve a certain projectile velocity.

This study aims to account for the uncertainties associated with two-stage gas guns using machine learning (ML) techniques. A dataset of 211 tests conducted at the UNLV two-stage gas gun with 0.22-inch caliber was used. Feature selection was performed and the most critical features were identified to train the ML models. The projectile velocities from each observation (experiment) were used as the dependent variable to produce training observations. Different regression techniques were evaluated. The predicted projectile velocities were then tested using the unused experimental dataset to verify the effectiveness of the models and to select the most accurate one. Among the tested models, the Random Forest model showed the best performance with R-Squared value above 94 %. The results showed that combining the experimental studies and Machine Learning can predict projectile velocities, saving time and cost of experimentation.
Evaluation of the Hydrogen Barrier Properties of Chromium Oxide Films Deposited on SUS304 Austenitic Stainless Steels
Authors: Kawami Kazuyoshi , Kinoshita Atsushi , Yamanaka Hisashi , Fukuda Yoji , Enoki Hirotoshi , Iijima Takashi , Fukuyama Seiji , Tsukane Ryo , Tanaka Toshiyuki , Fukutani Takeshi , Suzuki Yoshiaki , Tamai Hiroyasu , Ogi Takashi , Tamura Motonori
Published: November 2022

Austenitic stainless steels including type SUS304 of the Japanese Industrial Standard (JIS), which is similar to ASME Type 304 SS, are candidate materials for the various facilities of high-pressure gaseous hydrogen, such as a hydrogen station containers and piping. To prevent the hydrogen penetration into SUS304, we developed the passivation films mainly composed of chromium oxide and investigated the hydrogen barrier properties using the gas permeability test and the slow strain rate tensile (SSRT) test. The passivation films with a maximum thickness of 300 nm was formed on the surface of hot-rolled SUS304 (Ni equivalent 22.4) by a series of wet processing steps such as electro-polishing, chemical oxidation, cathode precipitation of chromium and passivation immersion. Cross-sectional views of TEM observation suggested that the film was amorphous like structure including many independent voids with a size of 10 to 20 nm. The hydrogen gas permeability test was performed in a hydrogen gas pressure of 400 kPa at 573 K, 673 K, and 773 K. The estimated hydrogen transmittance of SUS304 substrate with passivation coating was 2.8 × 10−13 mol / (m · s · Pa) at 773 K, while that without passivation coating was 2.2 × 10−11 mol / (m · s · Pa) at 773 K. SSRT test was performed in 110 MPa hydrogen and nitrogen gas atmosphere at room temperature, and strain rate was 4.17 × 10−5 s−1. The fracture surface of the specimen without passivation coating showed brittle like and relative reduction rate (RRA) was 0.61. On the other hand, the fracture surface of the specimen with passivation coating showed typical ductile like dimple structure and RRA was 0.88. As the passivation films did not peel, adhesion between passivation film and SUS304 surface seems to be well. From these considerations, we anticipate the developed passivation film can inhibit hydrogen embrittlement of SUS304.
Evaluation of Stainless Steels Welds Produced by Gas Tungsten Arc Welding With High Silicon Containing Solid Welding Filler Rod to Omit Back Shielding
Authors: Takahashi Atsushi
Published: November 2022

Where single-sided welding is applied to fabrication and erection of piping made of low alloy steels, stainless steels (SS) and nonferrous alloys, back shielding by inert gas and its maintenance for the first few layers is required to obtain good weldability and to prevent oxidation of welds.

In order to save consumption of inert gas, isolations to make a chamber for inert gas purging are placed inside piping for the joint and the adjacent areas to be welded, instead of inert gas purging for the whole piping length. However, placing the isolations before welding and removal of them after welding are sometimes impractical due to piping layout and construction sequence such as closure joints. To solve this issue, practices for omission of back shielding, such as use of flux cored welding filler rods for gas tungsten arc welding (GTAW) or high silicon welding wires for gas metal arc welding in modified wave short circuit mode (GMAW-S), had been developed and achieved the objective. These practices, however, require special training and qualifications for welders, close dimensional tolerance for fit-up, and special welding power source equipped with electrical waveform control. Also, welding quality such as remaining slag or spatters on piping internal is sometimes an issue.

To make up for these shortcomings, high silicon solid welding filler rod was introduced to stainless steel welding by GTAW to eliminate back shielding, and mock-up tests were conducted. The properties of the welds were studied by comparison to the welds produced by the other welding processes such as GTAW with back shielding, GTAW with flux cored filler rod without back shielding, and GMAW-S using high silicon solid wire without back shielding. This paper discusses and evaluates the potential of the GTAW with high silicon solid filler rod which can eliminate the inert gas back shielding.
Evaluation of Flashing Jet Impact on Surroundings Due to Leakage of High Pressure Pipes
Authors: Yuasa Tomohisa , Watanabe Shun , Morita Ryo
Published: November 2022

If the water piping system under high temperature and pressure is damaged and water is ejected into the atmosphere, a jet with depressurization boiling (Flashing) may occur. Therefore, it is necessary to evaluate the range of the jet impact on surrounding equipment and people. The range of the jet impact is evaluated by the existing code adopted in Japan (JSME S ND1) which referred to the standards adopted in America (ANSI/ANS-58.2-1988). The problem with this standard is that the experimental validity of the range of the jet impact has not been confirmed in Japan. In this study, we investigated experimentally to confirm the validity of the expanding angle and the affected area of the flashing jet of saturated water under low-pressure conditions, and further investigated the high-pressure conditions, which are difficult in the experiment, using Computational Fluid Dynamics (CFD).
Fatigue Crack Growth Assessment of Pipeline Steels and Girth Welds
Authors: Park Dong-Yeob , Liang Jie , Gravel Jean-Philippe
Published: November 2022

Fatigue test specimens were prepared and tested with an API 5L X70 spiral welded pipe steel and girth weld. For a few selected specimens, two unloading compliance techniques (elastic compliance and back-face strain compliance) were applied simultaneously to a single specimen for direct comparisons of in-situ crack size estimation. This paper also includes fatigue crack growth rate (FCGR) data of other pipe steels and welds available in the literature. It was observed that most FCGR curves of pipeline steels (X65∼X100) remained within the BS 7910 mean and upper bound design curves in the Paris region. On the contrary, the fatigue crack growth rate of the X42 pipeline steel from a reference was high — a very steep slope of the FCGR curve, crossing over the BS 7910 design criteria. It was noted that the FCGR of austenitic stainless pipe steel and girth weld obtained from Arora et al. (2014) showed a very excellent fatigue property.
Unique Failures in Explosion Bond Cryogenic Transition Joints
Authors: Colwell Richard L.
Published: November 2022

In cryogenic process plants that use aluminum alloy brazed core exchangers, a transition to austenitic stainless steel piping is often required. Presently, multi-layered explosion bonded piping joints provide that joint. These joints employ multiple layers of different alloys (e.g. 304L SS, Ni 200, Ti, Al, and Al-Mg), to provide the required leak-tight joint.

Analysis of a few recent failures of these joints have shown interesting properties on a micro scale within the nickel layer, adjacent to the titanium-nickel interface. This paper will discuss the morphology of cracks, and discuss potential causes.
Reliability-Based Assessment of Cracked Pipelines Using Monte Carlo Simulation Technique With CorLAS™
Authors: Zhang Xinfang , Zheng Qian , Leung Juliana , Adeeb Samer
Published: November 2022

If not assessed properly, unstable crack growth in pipelines could result in detrimental leaks or ruptures. Fracture mechanics models are typically used to assess the susceptibility of pipelines to fail due to the presence of cracks or crack-like anomalies. To this end, an inelastic (or elastic-plastic) fracture mechanics model, known as CorLAS™ model, has been developed and frequently used by pipeline operators. This paper first reviews the development of the CorLAS™ model and derives the probabilistic characteristics, including mean and coefficient of variation (COV) associated with the CorLAS™ model using a collection of 94 full-scale burst test data from the literature. A comprehensive reliability assessment of cracked pipes based on the CorLAS™ model is performed through the Monte Carlo Simulation (MCS) method. For each reported scenario, the probability of failure (PoF) is calculated by MCS that considers the uncertainties associated with various parameters such as pipe geometry, material properties, and the uncertainty due to the fracture model itself, namely, the model error. Finally, a sensitivity study is conducted considering various input parameters, including pipe grade, pipe diameter, wall thickness, ratio of crack length to depth, ratio of crack depth to wall thickness, and model error COV. The results suggest that the PoFs are highly sensitive to the COV, i.e., the PoFs increase significantly with the increase of the COVs, while the effects of other input parameters on the PoFs are insignificant. It is also shown that the model error COV of CorLAS™ with a value of 13% could serve as a reference value for future model error studies.
On API-661 and Assessment Procedures of Header Boxes and Nozzles for Air-Cooled Heat Exchangers
Authors: Zhao Mingxin
Published: November 2022

This paper presents a series of studies on header boxes and the attached inlet or outlet nozzles for air-cooled heat exchangers and associated data from API-661. Unlike cylindrical or spherical vessels, the rectangular-shaped cross section of a header box does not have a simple thickness equation that allows for determining the minimum required wall thicknesses from pressure. Though pressure vessel codes and relevant API standards provide certain design tool or fabrication data, a definite and consistent assessment procedure with necessary details is still not available. In many occasions this often imposes difficulties and confusion when conducting inspections and integrity assessments on air-cooled heat exchangers.

In this study, stress analysis methods for vessels with rectangular cross sections and the attached nozzles are reviewed and applied to assessments of air-cooled heat exchangers. Minimum nominal thicknesses from API-661 are examined and compared to analysis data for a variety of conditions to investigate the applicability and restrictions of the standard on inspection and integrity assessments of header boxes and attached nozzles. As a result, FFS assessment procedures in three different levels, which are consistent with API-579 general assessment methodology, are developed and presented for header boxes and nozzles. This study may serve as a practical addition to integrity assessments and inspection of air-cooled heat exchangers.