bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of sorbitan sesquioleate in patch test preparations and patch testing with the substance—What do our results mean?
Authors: Sukakul Thanisorn , Bruze Magnus , Mowitz Martin , Svedman Cecilia
Published: October 2022

Background

Sorbitan sesquioleate (SSO) is a sorbitan fatty acid ester, an emulsifier used in topical products and certain patch test preparations. SSO may affect the patch test results. It has been debated whether to include the substance in the baseline series to avoid misinterpretation of the results.

Objectives

To report the prevalence and simultaneous reactions of SSO with other patch test preparations containing SSO as an emulsifier.

Materials and Methods

A retrospective analysis of 3539 dermatitis patients who underwent patch testing from 2016 to 2020 was performed.

Results

The 5‐year SSO contact allergy prevalence was 0.48%, and 1.3% had a doubtful reaction. Patients with a stronger positive reaction (2+, 3+) were more likely to react simultaneously to other allergen preparations containing SSO (p value = 0.018). One patient with a strong reaction to SSO reacted positively to all SSO‐containing patch test preparations. Definite fragrance allergens could not be identified in the patients who had simultaneous reactions to SSO and fragrance mix (FM) I.

Conclusions

Patch testing with allergen preparations containing SSO affected the patch test interpretation. Fragrance contact allergy could not be ruled out when a patient simultaneously reacted to SSO and FM I. Changing emulsifiers in patch test preparations would be advantageous.
Acoustic presence and vocal activity of North Atlantic right whales in the New York Bight: Implications for protecting a critically endangered species in a human‐dominated environment
Authors: Murray Anita , Rekdahl Melinda L. , Baumgartner Mark F. , Rosenbaum Howard C.
Published: October 2022

North Atlantic right whale (NARW) distribution shifts have led to increased presence in the US mid‐Atlantic, which includes the New York Bight (NYB), an area with substantial vessel traffic. NARW vessel strikes are mitigated by a seasonal management area (SMA) that is active November–April. Within the SMA, vessels ≥ 19.8 m must travel at ≤10 knots. However, until recently, surveys of the NYB were not conducted after the NARW distribution shifted. Thus, it was unclear whether the SMA captured NARW presence in the NYB. Outside the SMA, voluntary speed restrictions are implemented over a limited area when NARW calls are acoustically detected; therefore, it was important to quantify NARW vocal activity. Acoustic recordings (2016–2020) were analyzed to determine NARW presence, vocal states, and diel pattern of vocal activity. NARWs were detected outside SMA boundaries, and medium/high vocal states (21–69 calls over 3–6 h) occurred while the SMA was inactive. Therefore, the SMA spatiotemporal boundaries should be revised. Vocal activity was highest at night (22:00–1:00), and NARWs were acoustically detected when they were not detected by aerial surveys, illustrating acoustic detections are a viable method for triggering mitigation measures when NARWs are vocalizing but are not visually observed.
Confirmatory reinforcement learning changes with age during adolescence
Authors: Chierchia Gabriele , Soukupová Magdaléna , Kilford Emma J. , Griffin Cait , Leung Jovita , Palminteri Stefano , Blakemore Sarah‐Jayne
Published: October 2022

Understanding how learning changes during human development has been one of the long‐standing objectives of developmental science. Recently, advances in computational biology have demonstrated that humans display a bias when learning to navigate novel environments through rewards and punishments: they learn more from outcomes that confirm their expectations than from outcomes that disconfirm them. Here, we ask whether confirmatory learning is stable across development, or whether it might be attenuated in developmental stages in which exploration is beneficial, such as in adolescence. In a reinforcement learning (RL) task, 77 participants aged 11–32 years (four men, mean age = 16.26) attempted to maximize monetary rewards by repeatedly sampling different pairs of novel options, which varied in their reward/punishment probabilities. Mixed‐effect models showed an age‐related increase in accuracy as long as learning contingencies remained stable across trials, but less so when they reversed halfway through the trials. Age was also associated with a greater tendency to stay with an option that had just delivered a reward, more than to switch away from an option that had just delivered a punishment. At the computational level, a confirmation model provided increasingly better fit with age. This model showed that age differences are captured by decreases in noise or exploration, rather than in the magnitude of the confirmation bias. These findings provide new insights into how learning changes during development and could help better tailor learning environments to people of different ages.

Research Highlights

Reinforcement learning shows age‐related improvement during adolescence, but more in stable learning environments compared with volatile learning environments.

People tend to stay with an option after a win more than they shift from an option after a loss, and this asymmetry increases with age during adolescence.

Computationally, these changes are captured by a developing confirmatory learning style, in which people learn more from outcomes that confirm rather than disconfirm their choices.

Age‐related differences in confirmatory learning are explained by decreases in stochasticity, rather than changes in the magnitude of the confirmation bias.
Retinoic acid effects on in vitro palatal fusion and WNT signaling
Authors: Roa Fuentes Laury Amelia , Bloemen Marjon , Carels Carine EL , Wagener Frank ADTG , Von den Hoff Johannes W
Published: October 2022

Retinoic acid is the main active vitamin A derivate and a key regulator of embryonic development. Excess of retinoic acid can disturb palate development in mice leading to cleft palate. WNT signaling is one of the main pathways in palate development. We evaluated the effects of retinoic acid on palate fusion and WNT signaling in in vitro explant cultures. Unfused palates from E13.5 mouse embryos were cultured for 4 days with 0.5 μM, 2 μM or without retinoic acid. Apoptosis, proliferation, WNT signaling and bone formation were analyzed by histology and quantitative PCR. Retinoic acid treatment with 0.5 and 2.0 μM reduced palate fusion from 84% (SD 6.8%) in the controls to 56% (SD 26%) and 16% (SD 19%), respectively. Additionally, 2 μM retinoic acid treatment increased Axin2 expression. Retinoic acid also increased the proliferation marker Pcna as well as the number of Ki‐67‐positive cells in the palate epithelium. At the same time, the WNT inhibitors Dkk1, Dkk3, Wif1 and Sfrp1 were downregulated at least two‐fold. Retinoic acid also down‐regulated Alpl and Col1a2 gene expression. Alkaline phosphatase (ALP) activity was notably reduced in the osteogenic areas of the retinoic acid‐ treated palates. Our data suggest that retinoic acid impairs palate fusion and bone formation by upregulation of WNT signaling.
Open dialogue trainees' perspectives on learning processes and psychotherapeutic practice: A prospective focus group study
Authors: Buus Niels , Ong Ben , McCloughen Andrea
Published: October 2022

Open Dialogue is a collaborative approach to mental health care emphasizing integrated services and a dialogical psychotherapy approach. Open Dialogue training programs eschew traditional didactic teaching of technical therapeutic skills in favor of more experiential learning processes. It is unclear how these training programs affect trainees and shape their perspectives on Open Dialogue. Our aim was to follow up a group of Australian Open Dialogue trainees and explore their perspectives on learning processes and psychotherapeutic practice. We utilized a prospective focus group design with data from audio‐recorded focus groups convened before (n = 2) and after (n = 3) participants completing an advanced Open Dialogue training program. Data were subjected to reflective thematic analysis. We identified the theme “Extending possibilities by holding ideas lightly,” which represented a universal principle that participants applied to multiple aspects of their practice, for example, favoring multiple perspectives and approaches to therapy, including those other than Open Dialogue. This theme had two sub‐themes: (1) “Allowing intimacy by being aware of personal biographies” and (2) “Learning by joining others,” which reflected an increased willingness by participants to reflect on and share their inner experiences and an emphasis on joint experiential exercises in the training program. “Extending possibilities by holding ideas lightly” facilitated a means of incorporating a dialogical perspective into existing practices thus avoiding the potential barriers to a wholesale implementation of Open Dialogue. Findings indicated that the participants were not learning how to practice a therapeutic technique or propositional knowledge, but were socialized into a dialogical way of being.
Military‐related stress, self‐efficacy, and anxiety: Investigating the role of marital quality in military couples
Authors: Lucier‐Greer Mallory , Frye‐Cox Nick , Reed‐Fitzke Kayla , Ferraro Anthony J. , Mancini Jay A.
Published: October 2022

This study utilizes a stress process framework in conjunction with a crossover perspective to conceptualize how stress, specifically military‐related stress, manifests within individuals and couples. An actor–partner interdependence mediation modeling approach was used in a cross‐sectional sample of 243 military couples to examine whether difficulties managing military‐related stress may erode one's own self‐efficacy and, in turn, contribute to greater anxiety (actor effects) and/or one's partner's self‐efficacy and, in turn, anxiety (partner effects). Further, the potential moderating impact of marital quality was explicated in the model to understand if greater marital quality might buffer the impact of military‐related stress. There was support for the stress process model primarily regarding actor effects; fewer partner effects emerged. One's own perceptions of military‐related stress, specifically higher stress, were related to lower levels of their own self‐efficacy, and, consequently, higher anxiety, but military‐related stress did not directly affect the partner's self‐efficacy or anxiety. Both service members' and civilian spouses' marital quality had ramifications for civilian spouses' self‐efficacy, specifically a buffering effect; that was not the case regarding civilian spouse effects on the military member. Findings point to specific ways in which military stressors have implications for personal well‐being, the role of a strong couple relationship in buffering stress, especially for civilian spouses, and concomitant leverage points for supporting both individual and couple well‐being.
Sulphated and carboxymethylated polysaccharides from Lycium barbarum L. leaves suppress the gelatinisation, retrogradation and digestibility of potato starch
Authors: Zhou Fa , Su Lijing , Xu Jiana , Wang Mengze , Fan Junfeng , Zhang Bolin , Li Yonghua
Published: October 2022

Processing starch with polysaccharides promotes broader applications, and it is important to consider all possible structural interactions among the molecular ingredients. In this study, polysaccharides isolated from Lycium barbarum L. were chemically modified by sulphation (SLP) and carboxymethylation (CLP), and the effects on the gelatinisation, retrogradation, and digestibility properties of the potato starch were investigated. After chemical modification, the slope of the curve between the molar mass and molecular radius of polysaccharides decreased, revealing that the relatively rigid rod‐like structure of native polysaccharide (0.78) changed to SLP's random linear chain (0.53) and CLP's spherical conformation (0.23), and the water solubility increased from 63.6% to 70.4% (SLP) and 84.1% (CLP) in distilled water at 25 °C. Moreover, testing polysaccharides as an additive indicated that both derivatives significantly decreased the peak viscosity, breakdown, and setback viscosity during potato starch pasting. Furthermore, the possible interactions could be further examined by structure analyses, suggesting the polysaccharide and SLP hydrogen bonds interacted with the surfaces of starch granules, while CLP penetrated the interiors of pasted starch granules, destroyed the helixes and backbone structure of starch, and formed type V crystallinity with amylose. The results of in vitro digestion analysis revealed that polysaccharides could decrease the amount of resistant starch and increase the amount of slowly digestible starch, which might be related to the inhibition of starch gelatinisation. These results facilitate the application of chemical derivatives in starch‐based functional foods and understand the interaction mechanism between potato starch and polysaccharides.
Effectiveness and safety of radium‐223 dichloride in patients with castration‐resistant prostate cancer and bone metastases in real‐world practice: A multi‐institutional study
Authors: Matsumoto Takashi , Hori Yoshifumi , Shiota Masaki , Blas Leandro , Nakamura Motonobu , Seki Narihito , Kuroiwa Kentaro , Yokomizo Akira , Morokuma Futoshi , Kiyoshima Keijiro , Eto Masatoshi
Published: October 2022

Objective

Radium‐223 (Ra‐223) dichloride is the bone‐targeted radioligand therapy that prolongs overall survival (OS) in patients with bone‐metastatic castration‐resistant prostate cancer (CRPC). We aimed to evaluate the safety and effectiveness of this treatment in real‐world practice.

Methods

We included Japanese men treated with Ra‐223 for bone‐metastatic CRPC from 10 institutions, retrospectively. Primary endpoint was OS. Secondary endpoint was maximum decline of alkaline phosphatase (ALP), lactate dehydrogenase, and prostate‐specific antigen values, the rate of adverse events, and time to pathological fracture after Ra‐223 treatment. Exploratory endpoint was the associations between clinical parameters and OS.

Results

In total, 73 men with bone metastatic CRPC treated with Ra‐223 were enrolled. The median OS was 20.9 months. ALP levels decreased significantly from pre‐treatment (p = 0.03). Anemia occurred in three (4.1%) patients. Grade ≥ 3 non‐pathological fractures occurred in four (5.5%) men. Nine (12.3%) patients presented pathological fracture; 7/30 (23.3%) were in men without concomitant use of a bone‐modifying agent (BMA) while 2/43 (4.7%) were in patients with concomitant BMA (p = 0.03). The median OS in patients with ≥3 cycles treatment (27.2 months, p < 0.001) or hemoglobin ≥12 g/dl (27.2 months, p = 0.001) or absence of bone pain (36.3 months, p = 0.004) was significantly longer compared to those who with ≤2 cycles or hemoglobin<12 g/dl or presence of bone paint, respectively.

Conclusions

This study has shown the outcomes of Ra‐223 treatment in real‐world practice, where the number of treatment cycles, baseline anemia and bone pain may be useful to predict OS in Ra‐223 treatment.
Migrant organisations, belonging and social protection. The role of migrant organisations in migrants' social risk‐averting strategies
Authors: Barglowski Karolina , Bonfert Lisa
Published: October 2022

This article contributes to the debates on migrant social protection assemblages by assessing enabling factors that provide migrants with opportunities to organise their social protection in changing environments. In‐depth interviews with migrants who use services from several migrant organisations (MOs) were conducted to study their largely neglected roles in social protection practices. Our findings indicate that MOs are important actors in the field of social protection, as they offer a variety of social services specifically tailored to migrants' needs, while concomitantly supporting them in developing a sense of belonging. Specifically, we identify three functions with which they enable their members to access and accumulate a range of resources relevant to protecting themselves against basic social risks: their networking, consulting, and familiarising functions. In doing so, we also draw attention to the connections between social protection strategies and evolving belongingness. Our findings confirm that MOs are multifunctional and highly responsive to individual needs and are therefore important actors in the field of social protection.
Money, Bitcoin, and Monetary Policy
Authors: KANG KEE‐YOUN , LEE SEUNGDUCK
Published: October 2022

A search‐theoretic model is constructed, where money and Bitcoin can be used as mediums of exchange. We investigate how each currency facilitates transactions and how they compete with each other. Quantitative analysis shows that welfare in an economy with both money and Bitcoin is lower than in a money‐only economy due to congestions in the confirmation of Bitcoin transactions and that the welfare gap between the two economies expands as inflation rises. Moreover, an increase in transaction fees for Bitcoin can increase welfare by reducing inefficient Bitcoin transactions.
Continuities of exploitation: seasonal migrant workers in German agriculture during the COVID‐19 pandemic
Authors: BOGOESKI VLADIMIR
Published: October 2022

Seasonal migrant agricultural workers were declared ‘essential’ in Germany at the very outset of the COVID‐19 pandemic. Two harvest seasons later, continuing poor working conditions, infection outbreaks on farms, and a general exclusion from social security schemes show that the recognition of the ‘essential’ character of the job has not translated into any improvements for workers. Based on interviews with trade union‐affiliated counsellors for migrant workers across Germany and analysis of the policies and legal measures introduced during the pandemic, this article demonstrates how pre‐existing institutional structures of exploitation in relation to seasonal agricultural work have been not only sustained but also reinforced.
Recruitment of distinct UDP‐glycosyltransferase families demonstrates dynamic evolution of chemical defense within Eucalyptus L'Hér
Authors: Hansen Cecilie Cetti , Sørensen Mette , Bellucci Matteo , Brandt Wolfgang , Olsen Carl Erik , Goodger Jason Q. D. , Woodrow Ian E. , Lindberg Møller Birger , Neilson Elizabeth H. J.
Published: October 2022

The economic and ecologically important genus Eucalyptus is rich in structurally diverse specialized metabolites. While some specialized metabolite classes are highly prevalent across the genus, the cyanogenic glucoside prunasin is only produced by c. 3% of species.

To investigate the evolutionary mechanisms behind prunasin biosynthesis in Eucalyptus, we compared de novo assembled transcriptomes, together with online resources between cyanogenic and acyanogenic species. Identified genes were characterized in vivo and in vitro.

Pathway characterization of cyanogenic Eucalyptus camphora and Eucalyptus yarraensis showed for the first time that the final glucosylation step from mandelonitrile to prunasin is catalyzed by a novel UDP‐glucosyltransferase UGT87. This step is typically catalyzed by a member of the UGT85 family, including in Eucalyptus cladocalyx. The upstream conversion of phenylalanine to mandelonitrile is catalyzed by three cytochrome P450 (CYP) enzymes from the CYP79, CYP706, and CYP71 families, as previously shown. Analysis of acyanogenic Eucalyptus species revealed the loss of different ortholog prunasin biosynthetic genes.

The recruitment of UGTs from different families for prunasin biosynthesis in Eucalyptus demonstrates important pathway heterogeneities and unprecedented dynamic pathway evolution of chemical defense within a single genus. Overall, this study provides relevant insights into the tremendous adaptability of these long‐lived trees.
High carbon resource diversity enhances the certainty of successful plant pathogen and disease control
Authors: Zhou Xing , Liu Liangliang , Zhao Jun , Zhang Jinbo , Cai Zucong , Huang Xinqi
Published: October 2022

The host‐associated microbiome highly determines plant health. Available organic resources, such as food for microbes, are important in shaping microbial community structure and multifunctionality. However, how using organic resources precisely manipulates the soil microbiome and makes it supportive of plant health remains unclear.

Here, we experimentally tested the influence of carbon resource diversity on the microbial trophic network and pathogen invasion success in a microcosm study. We further explored how resource diversity affects microbial evenness, community functions, and plant disease outcomes in systems involving tomato plants and thein vivosoil microbiome.

Increasing available resource diversity altered trophic network architecture, increased microbial evenness, and thus increased the certainty of successful pathogen control. By contrast, the invasion resistance effects of low resource diversity were less effective and highly varied. Accordingly, increases in the evenness and connection of dominant species induced by high resource diversity significantly contributed to plant disease suppression. Furthermore, high carbohydrate diversity upregulated plant immune system regulation‐related microbial functions.

Our results deepen the biodiversity‐invasion resistance theory and provide practical guidance for the control of plant pathogens and diseases by using organic resource‐mediated approaches, such as crop rotation, intercropping, and organic amendments.
A thematic analysis of barriers and facilitators to participant engagement in group exposure and response prevention therapy for obsessive–compulsive disorder
Authors: Leeuwerik Tamara , Caradonna Giorgia , Cavanagh Kate , Forrester Elizabeth , Jones Anna‐Marie , Lea Laura , Rosten Claire , Strauss Clara
Published: October 2022

Exposure and response prevention (ERP) is the gold standard in the treatment of the obsessive–compulsive disorder (OCD). It can be delivered effectively using an individual or group therapy format. Nonetheless, a sizeable proportion of people diagnosed with OCD do not experience OCD symptom remission following ERP. Research suggests that participant engagement with ERP tasks predicts therapy outcomes but there is little consistent evidence across studies on what predicts engagement. A recent meta‐analysis of participant engagement in cognitive‐behavioral therapy for OCD found that group ERP had a comparatively lower dropout rate than individual ERP. Little is known about participant perceptions of ERP to guide an understanding of how the group therapy format may affect participant engagement. This study conducted a qualitative exploration of what helps or hinders participants' engagement in group ERP. It involved thematic analysis of semi‐structured interview data collected at a 6‐month follow‐up from 15 adults with OCD who took part in group ERP. The study identified five main themes that captured participants' perceived facilitators and barriers to engagement in therapy: ‘Group processes’, ‘Understanding how to overcome OCD’, ‘Personal relevance’, ‘Personal circumstances’, and ‘Attitudes towards ERP’, which captured dynamically inter‐related barriers and facilitators at the level of the client, therapist, therapy and social environment. Each theme and associated sub‐themes are discussed in turn, followed by a consideration of the study's limitations and implications.
Depressive symptoms are associated with sarcopenia and malnutrition in older adults
Authors: Ulugerger Avci Gulru , Suzan Veysel , Bektan Kanat Bahar , Unal Damla , Emiroglu Gedik Tugce , Doventas Alper , Suna Erdincler Deniz , Yavuzer Hakan
Published: October 2022

Background

Depression is one of the most common mental disorders among older adults and depressive symptoms are strongly associated with adverse health outcomes. We aim to examine whether depressive symptoms are associated with sarcopenia and malnutrition in older adults.

Methods

We reviewed hospital records of 447 patients (≥65 years) who were admitted to the outpatient clinics, retrospectively. In addition to demographic characteristics, all participants were measured for usual gait speed (UGS), handgrip strength (HGS) and skeletal muscle mass (SMMI) by using bioelectrical impedance analysis. The Geriatric Depression Scale (GDS) was used to assess depressive symptoms. Nutritional status was screened by a mini‐nutritional assessment (MNA). Cognitive function was assessed from the Mini‐Mental State Examination (MMSE).

Results

Of the 215 participants who remained after performing exclusion criteria (a clinical diagnosis of dementia (n 63), stroke (n 61), Parkinson's disease or other neurodegenerative disease (n 30), previous depression diagnosis or antidepressant medication use (n 144)), the mean age was 78 ± 8.3, the majority were female (n 133) and almost half had depressive symptoms (49.3%). Thirty‐six percent had malnutrition, and 23 % had sarcopenia. The participants with depressive symptoms had lower MMSE scores (P < 0.001) and correlated with muscle mass (P < 0.001, r = −0.382), muscle strength (P < 0.001, r = −0.288), and MNA (P < 0.001, r = 0.355). Multivariate logistic regression showed that depressive symptoms were independently associated with low muscle strength (HGS: odds ratio (OR) 0.913, 95% CI: 0.866–0.962, P = 0.001), low muscle mass (SMMI: OR, 0.644, 95% CI: 0.509–0.814, P < 0.001), sarcopenia (OR, 2.536, 95% CI: 1.256–5.117, P = 0.009) and malnutrition (OR, 2.667, 95% CI: 1.467–4.850, P = 0.001).

Conclusion

This study demonstrated that depressive symptoms were independently associated with sarcopenia and malnutrition in older adults. Depressive disorders may lead to impaired cognitive dysfunction. Older adults at increased risk of sarcopenia and malnutrition should be screened for depression earlier.
Risk of tuberculosis among renal transplant recipients receiving rituximab therapy
Authors: Chandrashekhar Praveen , Kaul Anupma , Bhaduaria Dharmendra , Prasad Narayan , Behera Manas , Kushwaha Ravi , Patel Manas , Yachha Monika , Srivastava Aneesh
Published: October 2022

Background

Rituximab is an anti‐CD 20 agent used widely in renal transplant recipients. Its use is associated with various infections; however, its association with tuberculosis (TB) is not well established and has not been studied in post renal transplantation patients.

Methods

This is a single‐center, retrospective analysis of 56 renal transplant recipients who received rituximab as a part of desensitization protocol or as rescue therapy for rejections and 287 post‐renal transplant patients who did not receive rituximab during the study period from January 2013 to June 2017. The association between use of rituximab and occurance of TB was studied. Other factors associated with TB were also investigated.

Results

Baseline characteristics were similar in both the groups. Mean time for occurrence of TB was 18.4 ± 10.6 months after renal transplantation. Rituximab use was not significantly associated with TB or any other infection. Higher number of rejection episodes (60% vs. 32.72%, p = .029) was the only factor associated with greater incidence of TB. However, no specific type of rejection was associated with TB. Use of plasmapheresis in post‐transplant period for treatment of humoral rejections was associated with significantly higher incidence of TB (33.33% vs. 13.41%, p = .031); however, when pre‐transplant plasmapheresis was also considered, there was no significant difference. The choice of induction agent was not associated with higher incidence of TB.

Conclusion

Use of rituximab is not associated with higher incidence of TB when compared to other immunosuppressive agents. Routine screening and prophylaxis may not be advisable, especially in a country like India with high prevalence of TB, as it will further delay transplantation and may adversely affect the outcome of the patients.

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Creep Analysis and Microstructural Evaluation of a Novel Additively Manufactured Nickel-Base Superalloy (ABD®-900AM)
Authors: Bridges Alex , Shingledecker John , Clark John , Crudden David
Published: October 2022

Nickel-base superalloys containing 30 to 50% gamma prime (γ') volume fraction are typically used in hot section components (e.g., guide vanes or blades) for power generating gas turbines, and suitable time-dependent properties are required for long-term elevated temperature operation. Additive manufacturing (AM) has recently been used to develop complex hot-section parts utilizing innovative designs with enhanced cooling features which improve efficiencies by reducing cooling air consumption. To further explore the opportunity to improve time-dependent AM superalloys, this paper focuses on a fundamental creep study and characterization of a novel nickel-base superalloy (ABD-900AM) that was manufactured using a laser-based powder bed fusion (LBPBF) AM process. The material was subjected to a subsolvus solution anneal and multistep aging heat treatment (HT) to produce a bi-modal distribution with ∼35% volume fraction of gamma prime without postprocessing hot isostatic pressing (HIP). Microstructural characterization was carried out for the as-built and fully heat-treated structures, and a creep-rupture test program was conducted to study the resultant creep properties. Activation energies and stress exponents in addition to rupture strength and deformation resistance were compared to traditionally cast IN939 and IN738 materials. After testing, specimens were evaluated using a variety of microscopy tools to determine location and features associated with creep damage. The optimized chemistry for ABD-900AM was printed crack free and fully dense in contrast to studies on similar alloys where significant process development and postbuild heat treatments were required. High-temperature mechanical properties in the heat-treated material showed some decrease in creep strength when compared to traditional casting. This strength and rupture life debit was dependent on build orientation, but a considerable increase in creep ductility was observed due to differences in the microstructure when compared with similar AM alloys. Analysis of creep data showed differences in creep mechanisms compared to traditional cast alloys. The relationship between microstructure and creep mechanisms is discussed, and ongoing work to further improve rupture strength through heat-treatment optimization will be highlighted.
Experimentally Measured Effectiveness of Different Shroud Swirl Brake Profiles in a Centrifugal Compressor
Authors: Wilkes Jason , Smith Natalie , Venkataraman Balaji , Vagani Marco , Goucher Sara
Published: October 2022

As centrifugal compressors are pushed to operate at higher pressures and higher power levels, destabilizing gas forces often increase the challenge of designing a stable rotordynamic system. While technical innovations like damper seals, swirl brakes, and damper bearings that help stabilize compressors are numerous, predicting the impact that these improvements will have on a specific system is somewhat of an art form. To this end, researchers are constantly improving the depth of knowledge on these features so that the impact of these improvements is well defined. In the current work, the authors experimentally measured the impact of different swirl brake/vane concepts on the flow characteristics of a centrifugal compressor shroud cavity. The eye seal configuration studied here is a tooth on rotor labyrinth eye seal. The different shroud swirl vane geometries considered consist of various castellated features, each having the intent to reduce swirl velocity in the shroud cavity prior to entering the seal. The purpose of the testing was to determine whether a significant reduction in swirl velocity entering or exiting the seal could be measured with the different antiswirl vane profiles over a conventional shroud cavity that was tested with the same setup. The metrics that determine the effectiveness of the swirl brake were based on upstream and downstream measurements of swirl velocity using pitot-probes at different depths in the shroud cavity, and measurements of seal exit angle and velocity using a traversing cobra-probe. The test data presented herein show definitively that the different swirl brake designs, including a slotted seal, a long vane, and a short vane, have a major impact on swirl velocities relative to the conventional shroud design. The most effective at reducing swirl entering/leaving the seal is the slotted seal, while the concepts employing shroud vanes were more effective at reducing swirl in the shroud cavity.
From Concept to Wind Tunnel Model: Efficient Design Methodology for Innovative Low-Noise Propellers
Authors: Baert Lieven , Grasso Gabriele , Sainvitu Caroline , Lepot Ingrid , van Enkhuizen Marinus J. , Lammers Karel , Bown Nicholas
Published: October 2022

Whereas the market-share for propeller-driven aircraft is expected to rise to 30–40% of Europe’s regional aviation segment, a significant reduction in perceived noise levels remains a critical challenge for the success of further turboprop deployment. Within the framework of the Clean Sky 2 initiative, the Regional Aircraft platform focuses on the integration of technologies and methodologies, and their validation through full scale demonstrators, in order to allow for breakthrough technologies and competitive regional aircraft products.

This paper discusses the challenges for a low-noise propeller design, inherently multidisciplinary, and presents the design methodology employed from concept to wind tunnel model. Critical in the design process of disruptive and innovative concepts is the blade deformation from the manufactured (cold) shape to the running (hot) shape that must be adequately considered. An efficient online surrogate-based optimisation (SBO) approach has been followed where the machine learning models are locally enriched to improve their accuracy in the zones of interest of the design space. Throughout the optimisation feedback was integrated by dynamically strengthening and/or enforcing new constraints, resulting in a propeller design that satisfies all design requirements and achieves a significant near-field noise reduction of 6.4 dB compared to the baseline geometry. After performing a detailed structural assessment, the titanium propeller model has been manufactured and prepared for low-speed and high-speed wind tunnel testing. Preliminary results from the ongoing tests confirm the low-noise propeller’s potential.
Investigation of Tip Leakage Vortex Breakdown in a High-Speed Multistage Axial Compressor
Authors: Seki Ryosuke , Azuma Toshihiko , Iwatani Junji , Nakaniwa Akihiro , Okui Hidetaka , Shibata Takanori
Published: October 2022

In this paper, an unsteady tip leakage flow instability is identified and investigated for an axial compressor at near surge conditions. We describe the results of experimental verification of a new compressor developed by improving the blade geometry based on the criterion for the occurrence of this unsteady phenomenon.

In a high-speed multistage axial flow compressor having a subsonic high stagger rotor blade, a surge test was carried out by changing the tip clearance. Under a condition of large tip clearance, a drastic decrease in static pressure rise coefficient near the surge point was observed. At this operating condition, large, unsteady pressure fluctuation at the blade tip was confirmed, and the occurrence of tip leakage vortex breakdown that was clarified by unsteady multipoint pressure measurement and detailed unsteady numerical simulations. Due to the blockage effect caused by vortex breakdown of the tip leakage, double leakage and axially reversed flow near the trailing edge was observed. It is found that the vortex breakdown region of the tip leakage vortex propagated in the circumferential direction and caused the rotating instability.

In order to investigate the relationship between this unsteady flow phenomenon, tip clearance size and flow pattern, unsteady calculation was conducted by changing the blade tip stagger and tip clearance size. A new concept of tip clearance of staggered pitch reference is proposed, which makes it possible to include the effect of blade loading on the clearance and clarifies that there exists a threshold at which vortex breakdown occurs/does not occur.

On the basis of the above results, a high-speed multi-stage improved compressor was designed and manufactured to prevent tip leakage vortex breakdown. A clearance change test using active clearance control technology was conducted and increase in the static pressure rise coefficient near the surge point was confirmed for each clearance. The design concept of the improved blade which suppressed the unsteady tip leakage flow instability was tested and verified, and the effectiveness of the design guideline in actual gas turbines for power generation was confirmed.
Identification and Stability Analysis of a Turbojet Engine in Start-Up Mode
Authors: Abdulhamitbilal Erkan , Şal Sinan , Jafarov Elbrous M.
Published: October 2022

This paper investigates the system identification and stability analyses of a turbojet engine in start-up mode. Stability analyses are performed for automatic feedback control algorithm which switches engine from start-up to operational mode. This process requires engine rotational speed and acceleration data which are obtained via extensive engine tests. Those tests are carried out on an altitude testbed at sea level static conditions to obtain above mentioned data with respect to the fuel control command. The process consists of construction of a gain scheduled engine dynamics model and Lyapunov stability analyses. Engine dynamics are described as transfer functions. Mathematical model parameters are identified from test data to perform feasible stability analyses and to define feasible stability regions. The contribution of this study for a turbojet engine is the determination of stability maps in start-up mode and stability region or so-called strip for enabling strategy of the automatic feedback control law. The theoretical results are supported by simulations and an engine test example. Results show that the reference speed of the feedback control algorithm should be NREF ≤ NTJ + 10% for a successful stabilization while switching from start-up to operational mode.
Experimental Study of Film Cooling With Favorable and Adverse Pressure Gradients
Authors: Volino Ralph J. , Gillcrist Matthew C.
Published: October 2022

Film cooling experiments were conducted on a flat wall subject to favorable and adverse pressure gradients with constant acceleration parameter, K. The test wall included a single row of 5 round holes in line with the flow direction and inclined at 35 degrees to the surface. The hole spacing was 3 diameters. The wall opposite the test wall was moveable, and was set to angles with respect to the test wall that produced K values of −0.5 × 10−6, 0, 1 × 10−6, 2 × 10−6, 2.5 × 10−6, and 3 × 10−6. Blowing ratios of 0, 0.5, 1, and 1.5 were tested at each acceleration. The test wall was equipped with constant flux surface heaters, and data were acquired for each flow condition with the wall both heated and unheated. An infrared camera was used to record wall temperature in a region spanning the three center holes and extending 20D downstream of the holes. From these measurements, local film cooling effectiveness and heat transfer coefficients were determined. In the flow, velocity and temperature profiles were acquired using hot-wire anemometry and a traversing thermocouple probe. Particle image velocimetry was used to acquire velocity fields in a plane perpendicular to the flow direction and 10D downstream of the holes. The pressure gradient had a noticeable effect on the flow, with the favorable pressure gradient reducing liftoff and moving the film cooling jets closer to the wall, and reducing turbulence levels in the boundary layer. The adverse pressure gradient had the opposite effect. Near the wall, however, the effects of the pressure gradient on the film cooling effectiveness and heat transfer were more subtle.
Film Cooling Hole Shape Effects on Turbine Blade Heat Transfer – Part I: Computational Comparison to Experiment
Authors: Sperling Spencer , Christensen Louis , Mathison Randall , Aksoy Hakan , Liu Jong , Nickol Jeremy
Published: October 2022

Gas turbines generate highly unsteady flow fields, which are further complicated by cooling. Film cooling technology is dependent on experimental and computational research performed for simplified geometries, which can be difficult to translate to turbine domains. To help explain disconnects between flat plate experiments and turbine operation, this study performs computational research, grounded with experimental measurements, examining the film cooling performance of several different hole shapes on rotating turbine blades.

Round, fan, and advanced anti-vortex hole geometries are incorporated into experimental hardware and computational models, and pressure and heat flux results form a basis for comparisons between computation and experiment as well as between the cooling geometries. Unsteady and Steady simulations are both evaluated, and results indicate significant model accuracy improvement from the inclusion of unsteady consideration.

Shaped film cooling holes are observed to provide stronger film effectiveness traces on the blade. Both the fan and advanced shaped film cooling holes generate stronger cooling jet cores that remain close to the blade wall on the pressure surface, suction surface, and near the leading edge. Advanced shaped holes provide increased lateral spread and increased resistance to radial migration.

The results of this study help identify benefits of using shaped film cooling on the turbine blade as well as the mechanisms generating the cooling benefits. This will help designers weigh the manufacturing costs of shaped film cooling holes as well as identify areas of the blade where shaped film cooling is needed and where it is not. Additionally, this study observes significant improvements in blade heat transfer predictions through unsteady treatment alone, indicating better computational agreement can be achieved by leveraging lower-cost RANS simulation tools.
Design Optimization of Integrated Anti-Rotation Feature for Power Turbine Nozzles
Authors: Soman Abhimanyu , Colantoni Simone
Published: October 2022

Gas turbine nozzles are static components that are meant to turn and accelerate high temperature, high pressure, and low-velocity flue gas into the downstream turbine row of buckets. During gas turbine operation, nozzles are subjected to high-pressure load due to the expansion of flue gases, in axial and tangential directions. This creates a tendency for nozzle movement in tangential direction which has potential to create flow disturbance and intersegment gap opening. To prevent this movement, it should be held in tangential direction firmly by introducing an anti-rotation feature. A slot is introduced in the nozzle outer sidewall and a pin connected with casing in such a way that the nozzle’s tangential movement is restrained. As the nozzle’ s outer sidewall experiences high thermal gradients in the operating condition, it induces high stress at the nozzle anti-rotation feature. There are many possible design options available to mitigate this challenge. In the present work, anti-rotation feature is integrated with the nozzle’s outer sidewall and a matching slot is provided in the casing. A detailed study is performed to optimize this anti-rotation feature to reduce high thermal-mechanical stress and thereby improve reliability. The low cycle fatigue life is one of the vital requirements in improving reliability. The low cycle fatigue life of the optimized anti-rotation feature is validated using the finite element analysis. This paper describes the process step details in optimizing the anti-rotation feature.
Effect of Vane/Blade Interaction for a Cooled Turbine Blade — Part I: Comparison of Experimental and Numerical Results
Authors: Sperling Spencer , Christensen Louis , Mathison Randall , Aksoy Hakan , Liu Jong , Nickol Jeremy
Published: October 2022

Flow fields in axial gas turbines are highly complex and unsteady due to the interactions of rotating and stationary components. The current study incorporates experimental and computational analyses of a modern, rotating high-pressure turbine stage to examine the nature and effects of unsteadiness at vane passing scales. Increased knowledge of the unsteady flow field and its impacts on heat transfer will help engineers to produce higher quality thermal predictions of gas turbine components with efficient use of computing resources.

Computational research was carried out using single sector simulations using steady, sliding mesh, and harmonic balance treatments. Simulation results are compared to measurements of heat flux and pressure on the rotating airfoils of a cooled turbine stage operating at design corrected conditions.

Unsteady analysis of experimental and computational results highlights the importance of unsteady considerations in gas turbine research. Simulation results of unsteady pressure and heat transfer linked to vane passing perform well in some regions of the blade, but single sector computations cannot predict frequencies below vane passing frequency. It is therefore important to perform experiments and simulations in turbine representative environments.

Comparisons between results from the various computational models and experimental data form a basis for evaluating the benefits and drawbacks for each type of model treatment. Harmonic balance and sliding mesh simulations both increase the level of agreement between heat transfer data and results to within unsteadiness bounds, and each tends to have specific advantages. Harmonic balance simulations are particularly well equipped for comparisons in the frequency domain, but nearly double the memory requirement, making them more expensive to perform.

Part I of this paper focuses on the computational approaches implemented and how they compare to experimental results. Part II investigates the unsteady mechanisms that cause differences between steady and time-accurate solutions, as well as how they impact the flow over the rest of the airfoil.