bluuebunny/crossref_metadata_2025 huggingface dataset:
Caring responsibility from the perspectives of older persons whose adult children are their caregivers
Authors: Andersen Helle Elisabeth , Hoeck Bente , Nielsen Dorthe Susanne , Ryg Jesper , Delmar Charlotte
Published: July 2020

Aim

To describe lifeworld insights into the phenomenon of caring responsibility from the perspectives of persons aged 80+ years living alone with chronic illness, physical frailty and dependency on adult children.

Design

A phenomenological inquiry inspired by Reflective Lifeworld Research.

Method

Semi‐structured lifeworld interviews with 11 persons aged 80+ years were conducted following their discharge. The interviews lasted 35–83 min, were audio‐recorded and transcribed verbatim. Both interviews and the analysis followed the epistemological and methodological principles of Reflective Lifeworld Research.

Findings

We identified the essential meaning ‘It means everything’ and four constituents illuminating different aspects inherent in the complex phenomenon of caring responsibility; ‘A life‐constraining transition,’ ‘Trusting the children to fill the gaps and be the glue,’ ‘Tacit responsibility, agreement and acceptance’ and ‘Depending on the children and knowing they are burdened by you.’

Conclusions

Caring responsibility is based on a trusting relationship and tacit agreements indicating an understanding of interdependence and acceptance of dependence on adult children. However, a paradox appears when older persons express a deep‐rooted perception of autonomy and independence as they have difficulties with their growing dependency and feelings of being burdensome. Older persons try to balance the continuum of autonomy, their existential self‐image and actual capability. The practical part of caring responsibility seems to dominate and strongly affect the parent–child relationship because the child needs to take care of practical issues related to healthcare management and instrumental activities of daily living, leaving less time for meaningful togetherness.

Implications for practice

Older persons want their adult children to be involved and acknowledged when planning care and treatment because they often seem to serve as the ‘glue’ that makes it possible for the parent to remain in his/her own home.
Meibomian glands structure in daily disposable soft contact lens wearers: a one‐year follow‐up study
Authors: Llorens‐Quintana Clara , Garaszczuk Izabela K. , Szczesna‐Iskander Dorota H.
Published: July 2020

Purpose

To assess the impact of daily disposable soft contact lenses on meibomian gland morphology over a period of 12 months.

Methods

Forty‐one subjects (33 experienced and 8 neophytes) were fitted with either silicone‐hydrogel or hydrogel daily contact lenses. The study protocol included four visits: baseline, day‐2 for contact lens fit and follow‐up measurements, as well as after 6 and 12 months of lens wear. Non‐contact infrared meibography images were acquired with Keratograph 5M topographer (www.oculus.de) and analysed with an automated method, which objectively estimates the area of gland atrophy, gland length and width, number of glands and gland irregularity. Protocol at follow‐up visits also included symptom assessment with the Ocular Surface Disease Index and clinical assessment of tear meniscus height, bulbar and limbal redness, tear osmolarity, non‐invasive fluorescein break‐up time and ocular surface staining.

Results

Statistically significant differences were found in gland atrophy (p = 0.02) and length (p = 0.008) between experienced and novel contact lens wearers at the baseline visit. Changes over time (after 6 and 12 months) were found in gland atrophy (p = 0.02) and the number of glands (p = 0.01) in subjects fitted with hydrogel contact lenses. Changes in gland atrophy between baseline and 12 months of lens wear correlated with changes in corneal staining (r = 0.40, p = 0.03) and fluorescein break‐up time in subjects fitted with silicone‐hydrogel lenses (r = 1−0.43, p = 0.02).

Conclusions

Contact lens wear impacts meibomian gland morphology. However, changes are either long‐term or characteristic to an early phase. Subjects with no history of contact lens wear exhibit better meibomian gland condition than experienced wearers. During one year of contact lens wear, meibomian gland morphology changes in subjects wearing daily disposable hydrogel lenses.
The Population of Centenarians in Brazil: Historical Estimates from 1900 to 2000
Authors: Nepomuceno Marília R. , Turra Cássio M.
Published: July 2020

Since the nineteenth century, the census has provided the number of 100‐year‐olds in Brazil, one of the most populous countries worldwide. In 1900, 4,438 individuals reported themselves to be centenarians, a figure that increased about fivefold by the 2000 census. However, due to data quality issues, we are skeptical about the real size of the recorded population in the Brazilian census. We offer alternative estimates of the most likely number of centenarians during the twentieth century by combining variable‐rrelations with different mortality models. Our results indicate there was virtually no centenarian at the beginning of the twentieth century. The population has become larger than 1,000 individuals only in the 1990s, suggesting there has been an extensive, although diminishing, overenumeration of centenarians in the census records. Our results can help policymakers to plan the demands of a growing old age population in places that face stricter family and public budget constraints.
Perceived social support moderates neural reactivity to emotionally valenced stimuli during pregnancy
Authors: Nyman Tristin , Pegg Samantha , Kiel Elizabeth J. , Mistry‐Patel Sejal , Becker‐Schmall Lisa J. , Brooker Rebecca J.
Published: July 2020

Reactivity to emotional information, measurable at the level of neural activity using event‐related potentials, is linked to symptoms of affective disorders. Behavioral evidence suggests that contextual factors, such as social support, can alter emotional reactivity such that affective responding is normalized when social support is high. This possibility remains largely untested at the neural level, specifically through approaches that can offer insight into the mechanistic processes contributing to individual differences in emotional reactivity. Yet, such knowledge could be useful for prevention and intervention efforts, particularly with groups at risk for increased emotional reactivity, such as pregnant mothers for whom emotional distress predicts both maternal and child outcomes. Expectant mothers took part in a longitudinal study that tested whether the late positive potential (LPP), a neural index of reactivity to emotional information, was moderated by maternal perceptions of social support. In the third trimester of pregnancy, lower perceived social support was associated with an absence of a traditional LPP effect, which differentiates valenced from neutral stimuli. Findings suggest that perceptions of social support may normalize emotional processing at the neural level and highlight the potential importance of social support modulation of emotional reactivity during times of known biological change.
A latent change score approach to understanding dynamic autonomic coordination
Authors: Rudd Kristen L. , Yates Tuppett M.
Published: July 2020

Children's self‐regulation is a core adaptive system in child development. Physiological indices of regulation, particularly the autonomic nervous system (ANS), have garnered increased attention as an informative level of analysis in regulation research. Cardiography supports the simultaneous examination of both ANS branches via measures of pre‐ejection period (PEP) and respiratory sinus arrhythmia (RSA) as indicators of sympathetic and parasympathetic activity, respectively. However, despite their heavily intertwined functions, research examining autonomic coordination across sympathetic and parasympathetic systems is scarce. Moreover, extant efforts have favored static, mean level reactivity analyses, despite the dynamic nature of ANS regulation and the availability of analytic tools that can model these processes across time. This study drew on a sample of 198 six‐year‐old children from a diverse community sample (49.5% female, 43.9% Latinx) to examine dynamic autonomic coordination using bivariate latent change score modeling to evaluate bidirectional influences of sympathetic and parasympathetic activity over the course of a challenging puzzle completion task. Results indicated that children evidenced reciprocal sympathetic activation (i.e., PEP attenuation and RSA withdrawal) across the challenge task, and these regulatory responses were characterized by a temporally leading influence of PEP on lagging changes in RSA. The current findings contribute to our understanding of children's autonomic coordination while illustrating a novel analytic technique to advance ongoing efforts to understand the etiology and developmental significance of children's physiological self‐regulation.
A comparison of the bioremediation potential of five seaweed species in an integrated fish‐seaweed aquaculture system: implication for a multi‐species seaweed culture
Authors: Kang Yun Hee , Kim Sangil , Choi Sun Kyeong , Lee Hyuk Je , Chung Ik Kyo , Park Sang Rul
Published: July 2020

We investigated the growth and bioremediation potential of five local seaweed species (Codium fragile, Ulva pertusa, Ecklonia stolonifera, Saccharina japonica and Gracilariopsis chorda), using an integrated fish‐seaweed culture system as a biofilter for effluents from black rockfish (Sebastes schlegelii) tanks. The specific growth rate, biomass and net yield values of green algae were higher than those of brown algae. The tissue N and P levels of all species increased at the end of the experiment, but N:P ratios varied among seaweed species. The uptake rate and efficiency of total ammonia nitrogen uptake were the highest in U. pertusa and lowest in S. japonica. The phosphate uptake efficiency among all species ranged from 43% for S. japonica to 30% for G. chorda. These results suggest that all species can efficiently remove enriched nitrogen and phosphorus from fish tank effluents and are suitable for integrated aquaculture and bioremediation. However, inter‐specific differences were observed among seaweeds with regard to the biofiltration performance for different forms of nitrogen. The highest total oxidized nitrogen (ToxN) uptake efficiency was observed in E. stolonifera and S. japonica, while the lowest was observed in U. pertusa. ToxN uptake rates of E. stolonifera and S. japonica was 1.8 times higher than that of U. pertusa. Thus, a seaweed polyculture that included species with varying nitrogen source‐specific biofiltration activities might allow us to remove nutrients from effluents more effectively. These results provide valuable information regarding the selection of optimal seaweed species in fish‐seaweed integrated systems.
The rise of the Swiss regulatory healthcare state: On preserving the just in the quest for the better (or less expensive?)
Authors: Levy Melanie
Published: July 2020

Political theories of the modern state describe a rise of the regulatory healthcare state, balancing the imperatives of cost control and quality assurance and welfare norms such as solidarity. This paper analyses the unique case of Switzerland, where the rise of the regulatory healthcare state occurred late and incompletely, with the adoption of the Federal Health Insurance Law in 1994. The Swiss federal state pursues the social objective of universal access to healthcare through social health insurance regulation. This paper demonstrates that economic efficiency has not been the primary goal of healthcare coverage within the Swiss regulatory healthcare state despite rising costs. As another exceptional feature, Switzerland has diverged from the traditional path of judicial behavior in the regulatory state. This paper critically dissects how the Swiss Federal Court has become a crucial actor, imposing limits on access to healthcare and shaping decision‐making criteria for social regulation, such as cost‐benefit and cost‐impact analysis. Through this judicialization of limit‐setting, the judiciary engages in an ongoing constitutional dialogue on the limits of the regulatory welfare state and its sustainability for the future.
On The Interplay between Exposure Misclassification and Informative Cluster Size
Authors: McGee Glen , Kioumourtzoglou Marianthi-Anna , Weisskopf Marc G. , Haneuse Sebastien , Coull Brent A.
Published: July 2020

A recent multigenerational study of diethylstilbestrol and attention deficit hyperactivity disorder exhibited signs of both informative cluster size—the outcome was more prevalent in small families—and exposure misclassification—self-report of familial diethylstilbestrol exposure was substantially mismeasured. Motivated by this, we study the effect of exposure misclassification when cluster size is potentially informative and, in particular, when misclassification is differential by cluster size. We find that: misclassification in an exposure that is related to cluster size induces informativeness when cluster size would otherwise be non-informative; and misclassification that is differential by informative cluster size may attenuate, inflate or possibly reverse the sign of estimates. To mitigate these issues, we propose an observed likelihood correction for joint models of cluster size and outcomes, and an expected estimating equations correction. We evaluate these approaches in simulations and in application to the motivating data from the second Nurses Health Study, NHS II.
Sedimentary anatomy and hydrological record of relic fluvial deposits in a karst cave conduit
Authors: Bella Pavel , Gradziński Michał , Hercman Helena , Leszczyński Stanisław , Nemec Wojciech
Published: July 2020

This case study from the renowned Demänová Cave System in the Carpathians of Slovakia demonstrates that the conventional methods of fluvial sedimentology, combined with an allostratigraphic mapping and speleothem U‐series isotopic dating, can give unprecedented insights into the hydrological history of underground karst conduit. The deposits studied are a relic compound sidebar ranging from gravel to mud and encapsulating the conduit’s hydrological history from the middle Pleistocene to the present time. A succession of 10 allostratigraphic units, time‐constrained by speleothems, are recognized in the sidebar deposits, and the corresponding morphodynamics of an evolving cave‐floor sedimentation are reconstructed in considerable detail. The subterranean river water stages recognized from the deposits, time‐constrained by flowstone layers and stalagmites, correlate with and add to the regional record of climate changes. Two distinct episodes of flow ponding (high‐stage slackwater conditions) are recognized and attributed to the independently documented downstream cave‐roof collapses, probably triggered by the Carpathian post‐orogenic earthquakes. This multidisciplinary study may serve as a useful methodological guide for the analysis of fluviokarstic deposits in speleological research and reconstruction of their hosting cave hydrological history.
Attitudes towards Debt and Debt Behavior*
Authors: Almenberg Johan , Lusardi Annamaria , Säve‐Söderbergh Jenny , Vestman Roine
Published: July 2020

We introduce a novel survey measure of attitude towards debt. Matching our survey results with panel data on Swedish household balance sheets from registry data, we show that our measure of debt attitude helps to explain individual variation in indebtedness as well as debt build‐up and spending behavior in the period 2004–2007. As an explanatory variable, debt attitude compares well with a number of other determinants of debt, including education, risk‐taking, and financial literacy. We also provide evidence that suggests that debt attitude is passed down along family lines and has a cultural element.
Advancing the historical geography of late Ottoman and British Mandate Palestine using GIScience: A review
Authors: Zohar Motti
Published: July 2020

Late Ottoman Empire and Mandate Palestine are two important periods preceding independent Israel, characterized by increased attention to Palestine along with modernization processes and substantial landscape changes. Significant increase is also noted in survey and mapping, resulting in a wealth of visual sources. However, while textual sources were used intensively in various studies, the latter were analyzed to a much lesser extent. A major discipline based on the study of visual sources is historical geography. However, lately it seems that historical geography worldwide seeks for new approaches while struggling to retain dominancy in an environment becoming more computerized and technological. In this article I review the opportunities, pitfalls, and challenges of incorporating GIScience into the historical geography of late Ottoman and Mandate Palestine. Accordingly, it is suggested that a proper integration will contribute a substantial theoretical and methodological novelty while boosting the discipline of historical geography as well as other social sciences and humanities disciplines.
Characterization of ancestral myosin XI from Marchantia polymorpha by heterologous expression in Arabidopsis thaliana
Authors: Duan Zhongrui , Tanaka Misato , Kanazawa Takehiko , Haraguchi Takeshi , Takyu Akiko , Era Atsuko , Ueda Takashi , Ito Kohji , Tominaga Motoki
Published: July 2020

Previous studies have revealed duplications and diversification of myosin XI genes between angiosperms and bryophytes; however, the functional differentiation and conservation of myosin XI between them remain unclear. Here, we identified a single myosin XI gene from the liverwort Marchantia polymorpha (Mp). The molecular properties of Mp myosin XI are similar to those of Arabidopsis myosin XIs responsible for cytoplasmic streaming, suggesting that the motor function of myosin XI is able to generate cytoplasmic streaming. In cultured Arabidopsis cells, transiently expressed green fluorescent protein (GFP)‐fused Mp myosin XI was observed as some intracellular structures moving along the F‐actin. These intracellular structures were co‐localized with motile endoplasmic reticulum (ER) strands, suggesting that Mp myosin XI binds to the ER and generates intracellular transport in Arabidopsis cells. The tail domain of Mp myosin XI was co‐localized with that of Arabidopsis myosin XI‐2 and XI‐K, suggesting that all these myosin XIs bind to common cargoes. Furthermore, expression of GFP‐fused Mp myosin XI rescued the defects of growth, cytoplasmic streaming and actin organization in Arabidopsis multiple myosin XI knockout mutants. The heterologous expression experiments demonstrated the cellular and physiological competence of Mp myosin XI in Arabidopsis. However, the average velocity of organelle transport in Marchantia rhizoids was 0.04 ± 0.01 μm s−1, which is approximately one‐hundredth of that in Arabidopsis cells. Taken together, our results suggest that the molecular properties of myosin XI are conserved, but myosin XI‐driven intracellular transport in vivo would be differentiated from bryophytes to angiosperms.
Searching for remote homologs of CAML among eukaryotes
Authors: Borgese Nica
Published: July 2020

The tryptophan rich basic protein/calcium signal‐modulating cyclophilin ligand (WRB/CAML) and Get1p/Get2p complexes, in vertebrates and yeast, respectively, mediate the final step of tail‐anchored protein insertion into the endoplasmic reticulum membrane via the Get pathway. While WRB appears to exist in all eukaryotes, CAML homologs were previously recognized only among chordates, raising the question as to how CAML's function is performed in other phyla. Furthermore, whereas WRB was recognized as the metazoan homolog of Get1, CAML and Get2, although functionally equivalent, were not considered to be homologous. CAML contains an N‐terminal basic, TRC40/Get3‐interacting, region, three transmembrane segments near the C‐terminus, and a poorly conserved region between these domains. Here, I searched the NCBI protein database for remote CAML homologs in all eukaryotes, using position‐specific iterated‐basic local alignment search tool, with the C‐terminal, the N‐terminal or the full‐length sequence of human CAML as query. The N‐terminal basic region and full‐length CAML retrieved homologs among metazoa, plants and fungi. In the latter group several hits were annotated as GET2. The C‐terminal query did not return entries outside of the animal kingdom, but did retrieve over one hundred invertebrate metazoan CAML‐like proteins, which all conserved the N‐terminal TRC40‐binding domain. The results indicate that CAML homologs exist throughout the eukaryotic domain of life, and suggest that metazoan CAML and yeast GET2 share a common evolutionary origin. They further reveal a tight link between the particular features of the metazoan membrane‐anchoring domain and the TRC40‐interacting region. The list of sequences presented here should provide a useful resource for future studies addressing structure‐function relationships in CAML proteins.
Conform or challenge? Adjustment strategies of sanction‐torn companies
Authors: Weber Patrick Maximilian , Stępień Beata
Published: July 2020

The literature on sanctions often neglects the role of domestic firms in sender states, although sanctions only have a real economic effect when senders’ firms reduce their activities on the target's market. In contrast, sanctions avoidance and increasing investments in the target country (the observed behaviour of many companies facing the EU sanctions against Russia imposed in 2014) mitigate the impact of these restrictive measures. While sanctions increase the political risk for companies, they also offer economic opportunities—and previous studies could not settle the debate on which factor prevails. By evaluating responses from British, French, German, Italian and Polish enterprises to an online survey distributed in 2017, we analyse at the firm level how sanction‐torn companies adjust to new political orders and what drives their strategic decisions. We find evidence that resource dependency induces strategies that challenge sanction policies: in particular, non‐fungible assets in the target country incentivise companies to further increase their engagement. These defiance strategies diminish the real economic effect of sanctions and generate a new economic equilibrium, which has negative long‐term implications on the choice set of policymakers to further pursue the imposition of sanctions and which even outlasts the lifting of these restrictive measures.
Biologic variation of symmetric dimethylarginine and creatinine in clinically healthy cats
Authors: Prieto Jennifer M. , Carney Patrick C. , Miller Meredith L. , Rishniw Mark , Randolph John F. , Farace Giosi , Bilbrough Graham , Yerramilli Maha , Peterson Mark E.
Published: July 2020

Background

Biologic variation of biochemical analytes, both within individuals and between individuals, determines whether population‐based reference intervals (RIs) are appropriate when interpreting if a particular change is clinically relevant for a specific individual.

Objectives

We aimed to evaluate the biologic variation of symmetric dimethylarginine (SDMA) in clinically healthy cats.

Methods

A prospective, observational study was performed in which 10 clinically healthy, client‐owned cats were sampled for serum biochemical analyses once weekly for 6 weeks. Serum samples were frozen, and then single batches were analyzed for SDMA, using both liquid chromatography‐mass spectroscopy (LC‐MS), and an enzyme multiplied immunoassay technique (EMIT), and creatinine by modified Jaffe method. Restricted maximum likelihood estimations were used to determine the coefficients of variation (CVs) describing variation within each cat, between cats, and the analytical variation. These CVs were used to determine the indices of individuality and reference change values (RCVs).

Results

SDMA had an intermediate index of individuality that could be evaluated by both RCV and population‐based RIs. In contrast, creatinine had a high index of individuality best evaluated with RCVs. Serum SDMA concentrations evaluated with either the reference standard, LC‐MS, or the clinically used EMIT yielded similar results.

Conclusions

Clinicians should consider biologic variation when selecting the best method for interpreting changes in biochemical analytes. Specifically, establishing each cat's baseline serum creatinine and SDMA concentrations during health, and applying RCVs to subsequent measurements could improve the recognition of meaningful biologic changes.
Weed community responses to soil type during transition to no‐till practice on smallholder farms in Zimbabwe
Authors: Mavunganidze Zira , Madakadze Ignacio Casper , Nyamangara Justice , Mafongoya Paramu , Mashingaidze Nester
Published: July 2020

Understanding drivers of weed density and diversity is essential for the development of weed management strategies. Here, we compared temporal changes in weed density and diversity under no‐till (NT) and conventional (CONV) tillage systems in cotton–maize rotations on loam, clay loam and sandy loam soils immediately after transition to NT in Kadoma, Zimbabwe. The effect of tillage system on weed density varied through the growth season and was dependent upon soil type and species composition of the weed community. Although weed responses to tillage system varied amongst species, we identified general trend effects on weed density on specific soils. At 3 weeks after crop emergence (WACE), weed density on loam soils was 76% and 96% higher in NT than in CONV during the 2009/2010 and 2010/2011 seasons, respectively, and on clay loam soils it was 37% and 33% higher in NT than CONV, respectively. Weed densities in NT and CONV were similar across all soil types at 6 WACE during the 2009/2010 and 2010/2011 seasons and at 9 WACE in 2009/2010. Tillage system did not affect weed density during the growth season on sandy loam soils. Weed diversity (Shannon index) was at least 75% higher in NT than CONV on loam and clay loam soils at 3 WACE during both seasons. It is likely these increases in weed densities following conversion to NT will exacerbate already prevalent weed management problems in the smallholder sector. Earlier weeding is recommended to suppress weed emergence and reduce likely associated crop yield losses.
Effectiveness and safety of human amnion/chorion membrane therapy for diabetic foot ulcers: An updated meta‐analysis of randomized clinical trials
Authors: Huang Wentao , Chen Yongsong , Wang Nasui , Yin Guoshu , Wei Chiju , Xu Wencan
Published: July 2020

Human amnion/chorion membrane therapy has shown advantages in the management of diabetic foot ulcers and its effectiveness has been evaluated in the systematic reviews and meta‐analyses. However, the number of patients included in the previous literatures was small and the safety profile of human amnion/chorion membrane therapy was not concerned. Therefore, we conducted an updated meta‐analysis to better understand the effectiveness and safety of human amnion/chorion membrane therapy for diabetic foot ulcers. The PubMed, Embase, Cochrane Library, andClinicalTrial.govdatabases were searched for any randomized clinical trials comparing human amnion/chorion membrane therapy and standard therapy in the treatment of diabetic foot ulcers. Ulcer healing rate was considered as the primary outcome and the secondary outcomes mainly included mean time to ulcer healing and adverse events. Nine RCTs with 541 patients were included. Compared with merely standard therapy, human amnion/chorion membrane therapy plus standard therapy improved the ulcer healing rates at 6 weeks (RR = 3.50, 95% CI: 2.35‐5.21), 12 weeks (RR = 2.09, 95% CI: 1.53‐2.85) and 16 weeks (RR = 1.70, 95% CI: 1.25‐2.30), and also shortened the healing time (MD = −4.58, 95% CI: −5.70 to −3.46). Meanwhile, no significant difference was observed in the number of patients with adverse events (RR = 0.56, 95% CI: 0.31‐1.03) between two groups. This meta‐analysis suggests that human amnion/chorion membrane therapy as an adjuvant treatment could promote the healing of diabetic foot ulcers and has a safety profile. More evidence from large high‐quality randomized clinical trials with long follow‐up duration are in urgent need to further confirm our findings.
C‐Kit+ progenitors restore rat asthmatic lung function by modulation of T‐bet and GATA‐3 expression
Authors: Heiran Hossein , Ahmadi Mahdi , Rahbarghazi Reza , Mir‐ershadi Fatemeh , Delkhosh Aref , Khaksar Majid , Heidarzadeh Morteza , Keyhanmanesh Rana
Published: July 2020

New Findings

What is the central question of this study?

The aim of the experiment was to highlight the regenerative capacity of bone marrow Kit+ cells in the restoration of asthmatic pulmonary function in the rat model.

What is the main finding and its importance?

Data showed that these cells were recruited successfully to the asthmatic niche after intratracheal administration and accelerated the regeneration of asthmatic lungs by the modulation of inflammation via the control of Gata3 and Tbx21 expression, leading to decreased tracheal responsiveness to methacholine and reduction of pathological remodelling.

Allergic asthma is a T helper (Th) 2 immunological disorder with consequential uncontrolled inflammatory responses. There is an increasing demand to use new methods for the treatment of asthma based on modulation of the Th2‐to‐Th1 ratio in favour of the Th1 population. Accordingly, we decided to evaluate the effects of intratracheal administration of Kit+ bone marrow cells on tracheal responsiveness and the expression of Gata3 and Tbx21 genes. Forty male Wistar rats were allocated  randomly  into four experimental groups: healthy rats (control group), sensitized rats (OVA group), sensitized rats receiving Kit− cells (OVA+Kit− group) and sensitized rats receiving Kit+ cells (OVA+Kit+ group). Total and differential white blood cell counts, tracheal responsiveness to cumulative methacholine concentrations and histopathological analysis were evaluated. The results showed a statistically significant increase in total white blood cell, eosinophil and neutrophil counts, tracheal contractility, Gata3 expression and prototypical histopathology of asthma. Along with these conditions, we found that the number of lymphocytes was decreased and expression of Tbx21 diminished in sensitized rats compared with control animals. Monitoring of labelled tagged cells confirmed successful engraftment of transplanted cells in pulmonary tissue. Juxtaposition of Kit+ cells changed the blood leucogram closer to the control values. Kit+ cells increased the expression of Tbx21 and suppressed Gata3 (P < 0.05). In the OVA+Kit+ group, tracheal responsiveness was improved coincident with increased pulmonary regeneration. In conclusion, this study showed that intratracheal administration of bone marrow‐derived Kit+ cells, but not Kit− cells, could be effective in the alleviation of asthma, presumably by the modulation of Gata3 and Tbx21.
‘Resistance is futile?’ – paradoxical inhibitory effects of KATP channel closure in glucagon‐secreting α‐cells
Authors: Zhang Quan , Dou Haiqiang , Rorsman Patrik
Published: July 2020

By secreting insulin and glucagon, the β‐ and α‐cells of the pancreatic islets play a central role in the regulation of systemic metabolism. Both cells are equipped with ATP‐regulated potassium (KATP) channels that are regulated by the intracellular ATP/ADP ratio. In β‐cells, KATP channels are active at low (non‐insulin‐releasing) glucose concentrations. An increase in glucose leads to KATP channel closure, membrane depolarization and electrical activity that culminates in elevation of [Ca2+]i and initiation of exocytosis of the insulin‐containing secretory granules. The α‐cells are also equipped with KATP channels but they are under strong tonic inhibition at low glucose, explaining why α‐cells are electrically active under hypoglycaemic conditions and generate large Na+‐ and Ca2+‐dependent action potentials. Closure of residual KATP channel activity leads to membrane depolarization and an increase in action potential firing but this stimulation of electrical activity is associated with inhibition rather than acceleration of glucagon secretion. This paradox arises because membrane depolarization reduces the amplitude of the action potentials by voltage‐dependent inactivation of the Na+ channels involved in action potential generation. Exocytosis in α‐cells is tightly linked to the opening of voltage‐gated P/Q‐type Ca2+ channels, the activation of which is steeply voltage‐dependent. Accordingly, the inhibitory effect of the reduced action potential amplitude exceeds the stimulatory effect resulting from the increased action potential frequency. These observations highlight a previously unrecognised role of the action potential amplitude as a key regulator of pancreatic islet hormone secretion.

image
A Computational Investigation of the Impact of Multiple Injection Strategies on Combustion Efficiency in Diesel–Natural Gas Dual-Fuel Low-Temperature Combustion Engines
Authors: Bartolucci Lorenzo , Cordiner Stefano , Mulone Vincenzo , Krishnan Sundar R. , Srinivasan Kalyan K.
Published: July 2020

Dual-fuel diesel–methane low-temperature combustion (LTC) has been investigated by various research groups, showing high potential for emissions reduction (especially oxides of nitrogen oxide (NOx) and particulate matter (PM)) without adversely affecting fuel conversion efficiency in comparison with conventional diesel combustion. However, when operated at low load conditions, dual-fuel LTC typically exhibits poor combustion efficiencies. This behavior is mainly due to low bulk gas temperatures under lean conditions, resulting in unacceptably high carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. A feasible and rather innovative solution may be to split the pilot injection of liquid fuel into two injection pulses, with the second pilot injection supporting CO and UHC oxidation once combustion is initiated by the first one. In this study, diesel–methane dual-fuel LTC is investigated numerically in a single-cylinder heavy-duty engine operating at 5 bar brake mean effective pressure (BMEP) at 85% and 75% percentage of energy substitution (PES) by methane (taken as a natural gas (NG) surrogate). A multidimensional model is first validated in comparison with the experimental data obtained on the same single-cylinder engine for early single pilot diesel injection at 310 crank angle degrees (CAD) and 500 bar rail pressure. With the single pilot injection case as baseline, the effects of multiple pilot injections and different rail pressures on combustion and emissions are investigated, again showing good agreement with the experimental data. Apparent heat release rate and cylinder pressure histories as well as combustion efficiency trends are correctly captured by the numerical model. Results prove that higher rail pressures yield reductions of HC and CO by 90% and 75%, respectively, at the expense of NOx emissions, which increase by ∼30% from baseline still remaining at very low level (under 1 g/kWh). Furthermore, it is shown that postinjection during the expansion stroke does not support the stable development of the combustion front as the combustion process is confined close to the diesel spray core.
Optimizing Topology and Fiber Orientations With Minimum Length Scale Control in Laminated Composites
Authors: Luo Chuan , Guest James K.
Published: July 2020

Discrete material optimization (DMO) has proven to be an effective framework for optimizing the orientation of orthotropic laminate composite panels across a structural design domain. The typical design problem is one of maximizing stiffness by assigning a fiber orientation to each subdomain, where the orientation must be selected from a set of discrete magnitudes (e.g., 0 deg, ±45 deg, 90 deg). The DMO approach converts this discrete problem into a continuous formulation where a design variable is introduced for each candidate orientation. Local constraints and penalization are then used to ensure that each subdomain is assigned a single orientation in the final solution. The subdomain over which orientation is constant is most simply defined as a finite element, ultimately leading to complex orientation layouts that may be difficult to manufacture. Recent literature has introduced threshold projections commonly used in density-based topology optimization into the DMO approach in order to influence the manufacturability of solutions. This work takes this idea one step further and utilizes the Heaviside projection method within DMO to provide formal control over the minimum length scale of structural features, holes, and patches of uniform orientation. The proposed approach is demonstrated on benchmark maximum stiffness design problems, and numerical results are near discrete with strict length scale control, providing a direct avenue to controlling the complexity of orientation layouts. This ultimately suggests that projection-based methods can play an important role in controlling the manufacturability of optimized material orientations.
A Study on Basis Functions of the Parameterized Level Set Method for Topology Optimization of Continuums
Authors: Wei Peng , Yang Yang , Chen Shikui , Wang Michael Yu
Published: July 2020

In recent years, the parameterized level set method (PLSM), which rests on radial basis functions in most early work, has gained growing attention in structural optimization. However, little work has been carried out to investigate the effect of the basis functions in the parameterized level set method. This paper examines the basis functions of the parameterized level set method, including radial basis functions, B-spline functions, and shape functions in the finite element method (FEM) for topology optimization of continuums. The effects of different basis functions in the PLSM are examined by analyzing and comparing the required storage, convergence speed, computational efficiency, and optimization results, with the benchmark minimum compliance problems subject to a volume constraint. The linear basis functions show relatively satisfactory overall performance. Besides, several schemes to boost computational efficiency are proposed. The study on examples with unstructured 2D and 3D meshes can also be considered as a tentative investigation of prospective possible commercial applications of this method.
Research on the Influence of Clearance Variation on the Stiffness Fluctuation of Ball Bearing Under Different Operating Conditions
Authors: Fang Bin , Wan Shaoke , Zhang Jinhua , Hong Jun
Published: July 2020

The vibration induced by the varying compliance (VC) or the stiffness fluctuation of ball bearing plays a key role in the dynamic performance of the rotor system. The aim of this article is to study the stiffness fluctuation behaviors of ball bearing under different operating conditions. This article presents an improved mathematic model for ball bearing with wider applicability based on the new initial/reference position assumption and the ball-raceway contact/separation determination. The proposed model not only gets rid of the limitations of the raceway control hypothesis but also considers the space constraints of the cage on the balls. The advantages of the proposed model are presented through the typical working condition analysis, and the influences of the internal clearance on the stiffness and stiffness fluctuation of ball bearing under different operating conditions are given and discussed. The results show that bearing stiffness and stiffness fluctuation are determined by the external loads, rotating speeds, and internal clearances together, and properly increasing the axial load can effectively reduce the amplitudes and frequency components of the stiffness fluctuation. As an exploratory research work on the excitation source for the VC vibration of the bearing-rotor system, this article not only explains the complexity and diversity of the rotor VC vibration behavior from another side but also provides new ideas and important supplements for the rotor nonlinear analysis.
Design for Nonassembly: Current Status and Future Directions
Authors: Jung Sangjin , Laureijs Rianne E. , Combemale Christophe , Whitefoot Kate S.
Published: July 2020

Nonassembled products, which are produced from a raw material and post-processed to a final form without any assembly steps, form a large and potentially growing share of the manufacturing sector. However, the design for manufacturing literature has largely focused on assembled products and does not necessarily apply to nonassembled products. In this paper, we review the literature on design for nonassembly (DFNA) and the broader literature on design for manufacturing that has design guidelines and metrics applicable to nonassembled products, including both monolithic single-part products and nonassembly mechanisms. Our review focuses on guidelines that apply across multiple manufacturing processes. We identify guidelines and metrics that seek to reduce costs as well as provide differentiated products across a product family. We cluster the guidelines using latent semantic analysis and find that existing DFNA guidelines fall into four main categories pertaining to (1) manufacturing process, (2) material, (3) tolerance, and (4) geometry. We also identify existing product family metrics that can be modified for nonassembled products to measure some aspects of these categories. Finally, we discuss possible future research directions to more accurately characterize the relationships between design variables and manufacturing costs, including investigating factors related to the complexity of operations at particular process steps and across process steps.
Mode-Pursuing Sampling Method Using Discriminative Coordinate Perturbation for High-Dimensional Expensive Black-Box Optimization
Authors: Wu Yufei , Long Teng , Shi Renhe , Gary Wang G.
Published: July 2020

This article presents a novel mode-pursuing sampling method using discriminative coordinate perturbation (MPS-DCP) to further improve the convergence performance of solving high-dimensional, expensive, and black-box (HEB) problems. In MPS-DCP, a discriminative coordinate perturbation strategy is integrated into the original mode-pursuing sampling (MPS) framework for sequential sampling. During optimization, the importance of variables is defined by approximated global sensitivities, while the perturbation probabilities of variables are dynamically adjusted according to the number of optimization stalling iterations. Expensive points considering both optimality and space-filling property are selected from cheap points generated by perturbing the current best point, which balances between global exploration and local exploitation. The convergence property of MPS-DCP is theoretically analyzed. The performance of MPS-DCP is tested on several numerical benchmarks and compared with state-of-the-art metamodel-based design optimization methods for HEB problems. The results indicate that MPS-DCP generally outperforms the competitive methods regarding convergence and robustness performances. Finally, the proposed MPS-DCP is applied to a stepped cantilever beam design optimization problem and an all-electric satellite multidisciplinary design optimization (MDO) problem. The results demonstrate that MPS-DCP can find better feasible optima with the same or less computational cost than the competitive methods, which demonstrates its effectiveness and practicality in solving real-world engineering problems.
A Quantile-Based SORA Method Using Maximum Entropy Method With Fractional Moments
Authors: He Wanxin , Yang Hua , Zhao Gang , Zeng Yan , Li Gang
Published: July 2020

Reliability-based design optimization (RBDO) is receiving more attention from researchers because it can help to minimize cost reasonably in practical engineering. A large number of methods have been proposed to solve RBDO problems, most of which are based on the theory of the first-order reliability method (FORM). Therefore, the deficiencies of the FORM limit applications of general RBDO methods such as the dependency on the minimum performance target point (MPTP). In this study, we apply the fractional moment-based maximum entropy method to the RBDO problems for the first time and propose a novel RBDO method using the quantile-based sequential optimization and reliability assessment method. Because the proposed method is MPTP free, the shortcomings of FORM-based RBDO methods can be overcome. To demonstrate the performance of the proposed method, we test five numerical examples and one engineering example by the proposed method and three popular RBDO methods. The results show that the proposed method can balance the accuracy and the efficiency compared with other methods.
A Survey of Modeling and Optimization Methods for Multi-Scale Heterogeneous Lattice Structures
Authors: Liu Yuan , Zheng Guolei , Letov Nikita , Zhao Yaoyao Fiona
Published: July 2020

This paper aims to provide a comprehensive review of the state-of-the-art modeling and optimization methods for multi-scale heterogeneous lattice structures (MSHLS) to further facilitate the more design freedom. In this survey, a design process including optimization and modeling for MSHLS is proposed. Material composition and multi-scale geometric modeling methods for representation of material and geometry information are separately discussed. Moreover, the optimization methods including multi-scale and multi-material optimization design methods, as well as the simulation methods suitable for MSHLS are, respectively, reviewed. Finally, the relationship, advantages, and disadvantages of MSHLS modeling and optimization methods are summarized with discussion and comparison, which provides a guidance to further take advantage of MSHLS to improve the performance and multifunctional purpose of production for software developers and researchers concerning the design approaches and strategies currently available.
The Effect of Gapping on Compressor Performance
Authors: Przytarski Pawel J. , Wheeler Andrew P. S.
Published: July 2020

In this paper, we study the effect of rotor-stator axial gap on midspan compressor loss using high-fidelity scale-resolving simulations. For this purpose, we mimic the multi-stage environment using a new numerical method that recycles wake unsteadiness from a single blade passage back into the inlet of the computational domain. As a result, a type of repeating-passage simulation is obtained such as observed by an embedded blade-row. We find that freestream turbulence levels rise significantly as the size of the rotor-stator axial gap is reduced. This is because of the effect of axial gap on turbulence production, which becomes amplified at smaller axial gaps and drives increases in dissipation and loss. This effect is found to raise loss by between 5.5% and 9.5% over the range of conditions tested here. This effect significantly outweighs the beneficial effects of wake recovery on loss.