bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid post‐fire re‐assembly of species‐rich bryophyte communities in Afroalpine heathlands
Authors: Hylander Kristoffer , Frisk Carl Alexander , Nemomissa Sileshi , Johansson Maria Ulrika
Published: April 2021

Questions

In some fire‐prone ecosystems, bryophytes play a crucial role by providing the surface fuel that controls the fire return interval. Afroalpine heathlands are such an ecosystem, yet almost nothing is known about the bryophytes in this system. We do not know the level of species richness, or if there is a successive accumulation of species over time, or if some species are adapted to specific phases along the successional gradient, for example early‐successional species sensitive to competition.

Location

Afroalpine heathlands in Ethiopia.

Methods

We made an inventory of all bryophytes in 48 plots of 5 m × 5 m, distributed along a chronosequence from 1 to 25 years post fire. The heathlands are located between 3500 m and 3800 m a.s.l. and are managed by traditional pasture burning with fire intervals of 8–20 years.

Results

We found in total 111 taxa of bryophytes. Post‐fire mortality was almost 100%. The youngest plots had only a few cosmopolitan species often found after fire. Initially, species richness increased monotonically while starting to level off around 15 years after fire, when many plots had around 30 species and a high cover of Breutelia diffracta, which is a key ground‐living species, important as surface fuel. Most species were found with sporophytes, a pattern even stronger for the most frequent species.

Conclusions

Interestingly, bryophyte diversity is already remarkably high by only 15 years after total eradication. The relatively slow accumulation of species in the first years after fire suggests that dispersal in space, and not time, is the major mechanism by which sites regain their diversity (i.e. spore banks play a smaller role than colonization of wind‐borne spores). This indicates that the high species richness is built up through colonization from surrounding heathlands, and perhaps also from higher‐altitude alpine grasslands and lower‐altitude forests, and that the bryophyte diversity in this system is maintained by the traditional fire and grazing management.
A nonbile acid farnesoid X receptor agonist tropifexor potently inhibits cholestatic liver injury and fibrosis by modulating the gut–liver axis
Authors: Xiao Yongtao , Wang Ying , Liu Yang , Wang Weipeng , Tian Xinbei , Chen Shanshan , Lu Ying , Du Jun , Cai Wei
Published: April 2021

Background & Aims

Tropifexor (TXR) is a novel nonbile acid that acts as an agonist of farnesoid X receptor (FXR). TXR is currently in Phase 2 trials for the treatment of non‐alcoholic steatohepatitis (NASH). Herein, we report the impact of TXR on in a piglet model in which cholestatic liver damage and fibrosis where induced by bile duct ligation (BDL).

Methods

The piglets received BDL and TXR for 2 wk. Hepatic, portal and colonic bile acid and amino acid profiles and gut microbiome were analysed. Portal fibroblast growth factor (FGF) 19 levels were measured using an enzyme‐linked immunosorbent assay (ELISA).

Results

We first showed that bile acid metabolism and signalling are dysfunctional in patients with biliary atresia. Next, we observed that TXR potently suppresses BDL‐induced liver injury, fibrosis and ductular reaction in piglets. Within the ileum, TXR enhances FGF19 expression and subsequently increases portal FGF19 levels. In the liver, TXR promotes the expression of small heterodimer partner (SHP) and inhibits cholesterol 7α‐hydroxylase (CYP7A1). Additionally, TXR increases the abundance of bile acid‐biotransforming bacteria in the distal ileum and alters the composition of amino acids in the colon. Lastly, TXR ameliorates intestinal barrier injury in piglets subjected to BDL.

Conclusion

TXR potently ameliorated cholestatic liver injury and fibrosis by modulating the gut–liver axis in piglets. It supports the clinical evaluation of TXR as a therapeutic strategy for cholestatic liver diseases, such as biliary atresia.
Histological sub‐classification of cirrhosis using collagen proportionate area in patients with chronic hepatitis C
Authors: Papatheodoridi Margarita , Hall Andrew R. , Rodríguez‐Perálvarez Manuel , Pieri Giulia , Germani Giacomo , Gale Jeremy D. , Burgess Gary C. , Pinzani Massimo , Dhillon Amar P. , Tsochatzis Emmanuel A.
Published: April 2021

Collagen proportionate area (CPA, %) is used to quantify liver fibrosis. Here, we assessed CPA performance to sub‐classify cirrhosis. CPA was measured in explanted livers from consecutively transplanted patients for hepatitis C virus‐related cirrhosis. Model for end‐stage liver disease (MELD), Child‐Pugh score and decompensating events (ascites, variceal bleeding, non‐obstructive jaundice and encephalopathy) were recorded at the time of liver transplant. Of the 154 patients, 24%, 12%, 35%, 24% and 5% had zero, one, two, three and four previous decompensating events. Patients with decompensation had significantly higher CPA than those without (25.1 ± 8.4 vs 15.8 ± 5.5,P < .001). Decompensation was independently associated with CPA, bilirubin and albumin or with CPA and MELD score. CPA did not differ between patients with one, two, three or four decompensating events (22.2 ± 6.3 vs 26.6 ± 8.9 vs 24.5 ± 7.7 vs 24.4 ± 10.9,P = .242). Overall, CPA correlates with the clinical severity of cirrhosis until the advent of decompensation but not with subsequent decompensating events.
The impact and recovery of asteroid 2018 LA
Authors: Jenniskens Peter , Gabadirwe Mohutsiwa , Yin Qing‐Zhu , Proyer Alexander , Moses Oliver , Kohout Tomas , Franchi Fulvio , Gibson Roger L. , Kowalski Richard , Christensen Eric J. , Gibbs Alex R. , Heinze Aren , Denneau Larry , Farnocchia Davide , Chodas Paul W. , Gray William , Micheli Marco , Moskovitz Nick , Onken Christopher A. , Wolf Christian , Devillepoix Hadrien A. R. , Ye Quanzhi , Robertson Darrel K. , Brown Peter , Lyytinen Esko , Moilanen Jarmo , Albers Jim , Cooper Tim , Assink Jelle , Evers Läslo , Lahtinen Panu , Seitshiro Lesedi , Laubenstein Matthias , Wantlo Nggie , Moleje Phemo , Maritinkole Joseph , Suhonen Heikki , Zolensky Michael E. , Ashwal Lewis , Hiroi Takahiro , Sears Derek W. , Sehlke Alexander , Maturilli Alessandro , Sanborn Matthew E. , Huyskens Magdalena H. , Dey Supratim , Ziegler Karen , Busemann Henner , Riebe My E. I. , Meier Matthias M. M. , Welten Kees C. , Caffee Marc W. , Zhou Qin , Li Qiu‐Li , Li Xian‐Hua , Liu Yu , Tang Guo‐Qiang , McLain Hannah L. , Dworkin Jason P. , Glavin Daniel P. , Schmitt‐Kopplin Philippe , Sabbah Hassan , Joblin Christine , Granvik Mikael , Mosarwa Babutsi , Botepe Koketso
Published: April 2021

The June 2, 2018 impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. Twenty‐three meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as an HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of ~156 cm diameter with high bulk density ~2.85 g cm−3, a relatively low albedo pV ~ 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of ~0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth‐impacting orbit via the ν6 resonance. The impact that ejected 2018 LA in an orbit toward Earth occurred 22.8 ± 3.8 Ma ago. Zircons record a concordant U‐Pb age of 4563 ± 11 Ma and a consistent 207Pb/206Pb age of 4563 ± 6 Ma. A much younger Pb‐Pb phosphate resetting age of 4234 ± 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin.
Resuscitation of the microbial seed bank alters plant‐soil interactions
Authors: Kuo Venus , Lehmkuhl Brent K. , Lennon Jay T.
Published: April 2021

While microorganisms are recognized for driving belowground processes that influence the productivity and fitness of plant populations, the vast majority of bacteria and fungi in soil belong to a seed bank consisting of dormant individuals. However, plant performance may be affected by microbial dormancy through its effects on the activity, abundance, and diversity of soil microorganisms. To test how microbial seed banks influence plant‐soil interactions, we purified recombinant resuscitation promoting factor (Rpf), a bacterial protein that terminates dormancy. In a factorially designed experiment, we then applied the Rpf to soil containing field mustard (Brassica rapa), an agronomically important plant species. Plant biomass was ~33% lower in the Rpf treatment compared to plants grown with an unmanipulated microbial seed bank. In addition, Rpf reduced soil respiration, decreased bacterial abundance, and increased fungal abundance. These effects of Rpf on plant performance were accompanied by shifts in bacterial community composition, which may have diluted mutualists or resuscitated pathogens. Our findings suggest that changes in microbial seed banks may influence the magnitude and direction of plant‐soil feedbacks in ways that affect above‐ and belowground biodiversity and function.
Chaperone‐mediated coupling of subunit availability to activation of flagellar Type III secretion
Authors: Bryant Owain J. , Chung Betty Y.‐W. , Fraser Gillian M.
Published: April 2021

Bacterial flagellar subunits are exported across the cell membrane by the flagellar Type III Secretion System (fT3SS), powered by the proton motive force (pmf) and a specialized ATPase that enables the flagellar export gate to utilize the pmf electric potential (ΔΨ). Export gate activation is mediated by the ATPase stalk, FliJ, but how this process is regulated to prevent wasteful dissipation of pmf in the absence of subunit cargo is not known. Here, we show that FliJ activation of the export gate is regulated by flagellar export chaperones. FliJ binds unladen chaperones and, by using novel chaperone variants specifically defective for FliJ binding, we show that disruption of this interaction attenuates motility and cognate subunit export. We demonstrate in vitro that chaperones and the FlhA export gate component compete for binding to FliJ, and show in vivo that unladen chaperones, which would be present in the cell when subunit levels are low, sequester FliJ to prevent activation of the export gate and attenuate subunit export. Our data indicate a mechanism whereby chaperones couple availability of subunit cargo to pmf‐driven export by the fT3SS.
How does temperature trigger biofilm adhesion and growth in Candida albicans and two non‐Candida albicans Candida species?
Authors: Casagrande Pierantoni Debora , Corte Laura , Casadevall Arturo , Robert Vincent , Cardinali Gianluigi , Tascini Carlo
Published: April 2021

Background

Biofilm formation on biotic and abiotic surfaces is finely regulated by genetic factors but also by oxygen concentration, pH, temperature and other environmental factors, already extensively explored for bacterial biofilms. Much less is known about fungal biofilm, that is considered a virulence factor for Candida pathogenic species among the few fungal species able to grow and survive at high temperatures such as 37°C as well as those induced by fever. The resistance to high temperatures coupled with the ability to form biofilm are threatening factors of these fungal species that could severely impact at an epidemiological level.

Objectives

In this framework, we decided to study the thermal tolerance of biofilms formed by three medical relevant species such as Candida albicans and two non‐Candida albicans Candida species.

Methods

Thirty nosocomial strains were investigated for their ability to adhere and grow in proximity and over body temperature (from 31 to 43°C), mimicking different environmental conditions or severe febrile‐like reactions.

Results

Candida sessile cells reacted to different temperatures showing a strain‐specific response. It was observed that the attachment and growth respond differently to the temperature and that mechanism of adhesion has different outputs at high temperature than the growth.

Conclusions

This strain‐dependent response is probably instrumental to guarantee the best success to cells for the infection, attachment and growth to occur. These observations reinforce the concept of temperature as a major trigger in the evolution of these species especially in this period of increasing environmental temperatures and excessive domestic heating.
Relationship between sodium removal, hydration and outcomes in peritoneal dialysis patients
Authors: Mok Natalie M.‐Y. , Fan Nicholas , Finney Hazel , Fan Stanley L.‐S.
Published: April 2021

Background

Fluid overload (FO) in peritoneal dialysis (PD) patients is associated with mortality. We explore if low daily sodium removal is an independent risk factor for mortality. We examined severely FO PD patients established for >1 year in expectation that PD prescription would have been optimized for solute clearance and ultrafiltration. We also wish to determine the relationship between kt/v and sodium removal.

Methods

Retrospective analysis of 231 PD patients with FO ≥2.0 L and compared with 218 PD patients who were euvolaemic throughout their PD treatment. Patients were followed up until death censored for transplantation.

Results

Mean daily sodium removal in overhydrated patients was only 75 mmoles (=1.7 g). CAPD usage was more common in patients with the highest sodium removal. Achievement of UK guidelines for solute clearance and daily fluid removal were not independent predictors of mortality. Markers of sarcopenia (low serum albumin and high CRP) were associated with increased mortality, but these parameters were not independent predictors in a model that included functional assessment (Karnofsky score). Daily sodium removal was not predictive of mortality but the imprecision of clinically used sodium assay should be noted. The correlation between Na and kt/v is statistically significant but R2 was weak at .07.

Conclusion

While diabetic males were more likely to become overhydrated, these factors did not increase mortality further. Traditional targets of ‘dialysis adequacy’ did not predict survival. Kt/v is not a good indicator of sodium removal which can be surprisingly low. Measuring sodium clearance may help clinicians optimize PD modality (CAPD vs. APD).
Climate and functional traits jointly mediate tree water‐use strategies
Authors: Flo Victor , Martínez‐Vilalta Jordi , Mencuccini Maurizio , Granda Victor , Anderegg William R. L. , Poyatos Rafael
Published: April 2021

Tree water use is central to plant function and ecosystem fluxes. However, it is still unknown how organ‐level water‐relations traits are coordinated to determine whole‐tree water‐use strategies in response to drought, and whether this coordination depends on climate.

Here we used a global sap flow database (SAPFLUXNET) to study the response of water use, in terms of whole‐tree canopy conductance (G), to vapour pressure deficit (VPD) and to soil water content (SWC) for 142 tree species. We investigated the individual and coordinated effect of six water‐relations traits (vulnerability to embolism, Huber value, hydraulic conductivity, turgor‐loss point, rooting depth and leaf size) on water‐use parameters, also accounting for the effect of tree height and climate (mean annual precipitation, MAP).

ReferenceGand its sensitivity to VPD were tightly coordinated with water‐relations traits rather than with MAP. Species with efficient xylem transport had higher canopy conductance but also higher sensitivity to VPD. Moreover, we found that angiosperms had higher referenceGand higher sensitivity to VPD than did gymnosperms.

Our results highlight the need to consider trait integration and reveal the complications and challenges of defining a single, whole‐plant resource use spectrum ranging from ‘acquisitive’ to ‘conservative’.
Neuralgia‐inducing cavitational osteonecrosis – A systematic review
Authors: Sekundo Caroline , Wiltfang Jörg , Schliephake Henning , Al‐Nawas Bilal , Rückschloß Thomas , Moratin Julius , Hoffmann Jürgen , Ristow Oliver
Published: April 2021

Objective

To assess the aetiologic factors, proposed diagnostic means and treatment strategies for neuralgia‐inducing cavitational osteonecrosis.

Methods

A search of the literature published up to June 2020 was conducted using Medline, the Cochrane Library, PsycINFO, CINAHL and Web of Science. The scientific quality of the evidence was rated according to NIH Quality Assessment Tools.

Results

4,051 articles were found, 59 were reviewed in full text, and 29 studies were included. With the exception of hereditary coagulopathies, which were identified as potential risk factors in five studies, suggestions concerning the aetiology varied widely. No gold standard diagnostic mean could be identified. Treatment was most often performed by surgical curettage of the affected bone. Surgical treatment outcomes were equally varied: significant facial pain remission was reported in 66%–100% for periods varying between 2 months to 18 years, whereas no or little relief and recurrences were reported in up to ⅓ of cases. All studies were observational in their design. All investigations were rated as poor quality because of high risk of bias and non‐transparent reporting.

Conclusions

Evidence concerning the aetiology, diagnosis and treatment of NICO is poor. Prospective diagnostic and therapeutic studies are needed before the usefulness of invasive therapeutic procedures can be evaluated.
Newer‐generation antihistamines and the risk of adverse events in children: A systematic review
Authors: Miligkos Michael , Dakoutrou Maria , Statha Eleni , Theochari Nikoletta A. , Mavroeidi Ilektra Antonia , Pankozidou Ιoanna , Papaconstadopoulos Irene , Papadopoulos Nikolaos G.
Published: April 2021

Background

H1‐antihistamines (AHs) are widely used for the treatment of allergic diseases, being one of the most commonly prescribed classes of medications in pediatrics. Newer‐generation AHs are associated with fewer adverse effects compared with first‐generation AHs. However, their relative harms in the pediatric population still need scrutiny.

Methods

We performed a systematic review of randomized controlled trials (RCTs), which included comparisons of safety parameters between an orally administered newer‐generation AH and another AH (first‐ or second‐generation), montelukast, or placebo in children aged ≤12 years. We searched MEDLINE and CENTRAL, independently extracted data on study population, interventions, adverse events (AEs), and treatment discontinuations, and assessed the methodologic quality of the included RCTs using the Cochrane’s risk of bias tool.

Results

Forty‐five RCTs published between 1989 and 2017 met eligibility criteria. The majority of RCTs included school‐aged children with allergic rhinitis and had a follow‐up period of up to a month. Four RCTs reported serious AEs in patients receiving a newer‐generation AH, but only two patients experienced a possibly drug‐related serious AE. The occurrence of AEs, drug‐related AEs, and treatment discontinuations due to AEs varied between RCTs. Most AEs reported were of mild intensity. Indirect evidence indicates that cetirizine is more sedating than the other newer‐generation AHs.

Conclusion

Our findings confirm that newer‐generation AHs have a favorable safety and tolerability profile. However, we could not draw firm conclusions regarding the comparative safety profile of the newer‐generation AHs due to the paucity of head‐to‐head RCTs, variation in definitions and reporting of AEs, and short follow‐up duration.
Early age exposure to moisture and mould is related to FeNO at the age of 6 years
Authors: Tischer Christina , Karvonen Anne M. , Kirjavainen Pirkka V. , Flexeder Claudia , Roponen Marjut , Hyvärinen Anne , Renz Harald , Frey Urs Peter , Fuchs Oliver , Pekkanen Juha
Published: April 2021

Background

Exposure to indoor moisture damage and visible mold has been found to be associated with asthma and respiratory symptoms in several questionnaire‐based studies by self‐report. We aimed to define the prospective association between the early life exposure to residential moisture damage or mold and fractional exhaled nitric oxide (FeNO) and lung function parameters as objective markers for airway inflammation and asthma in 6‐year‐old children.

Methods

Home inspections were performed in children's homes when infants were on average 5 months old. At age 6 years, data on FeNO (n = 322) as well as lung function (n = 216) measurements were collected. Logistic regression and generalized additive models were used for statistical analyses.

Results

Early age major moisture damage and moisture damage or mold in the child's main living areas were significantly associated with increased FeNO levels (>75th percentile) at the age of 6 years (adjusted odds ratios, 95% confidence intervals, aOR (95% CI): 3.10 (1.35‐7.07) and 3.16 (1.43‐6.98), respectively. Effects were more pronounced in those who did not change residential address throughout the study period. For lung function, major structural damage within the whole home was associated with reduced FEV1 and FVC, but not with FEV1/FVC. No association with lung function was observed with early moisture damage or mold in the child's main living areas.

Conclusion

These results underline the importance of prevention and remediation efforts of moisture and mold‐damaged buildings in order to avoid harmful effects within the vulnerable phase of the infants and children's immunologic development.
Naïve realism and the problem of illusion
Authors: Overgaard Søren
Published: April 2021

As standardly conceived, an illusion is a case in which appearances in at least one respect conflict with reality. Such a conflict only obtains in cases where a non‐F object appears to be F—appears F in a ‘committal’ way, as I put it. It is, however, possible for an object to appear F in a non‐committal way—i.e. without appearing to be F. The paper discusses a number of recent naïve realist attempts to account for illusion. Drawing on the distinction between committal and non‐committal appearances, I argue that none of the proposals is able to account for illusion as standardly conceived.
Care left undone and work organisation: A cross‐sectional questionnaire‐based study in surgical wards of Estonian hospitals
Authors: Peterson Helle , Uibu Ere , Kangasniemi Mari
Published: April 2021

Background

Care left undone is a worldwide problem for both the quality of health care and the safety of patients. In surgical nursing, care left undone is a critical issue arising from the intensive pace of work, invasive procedures and the pressure for efficiency. Previous knowledge about care left undone in surgical contexts is missing.

Objective

To describe care left undone and its relationship to nursing and organisational characteristics in the surgical wards of regional and central hospitals in Estonia.

Methods

A cross‐sectional study with an online questionnaire took place from June to October of 2018. The target population (N = 570) consisted of nurses working in the surgical wards of two regional and three central hospitals at the time of the study. The data were analysed using descriptive statistics and Fisher's exact test. The open‐ended questions were analysed with deductive content analysis.

Results

Nursing care in the surgical wards was reported as having been left undone sometimes or often by 88% of the nurses. Most often, the documentation and evaluation of care plans (33%) were reported as undone and most rarely, disinfection measures were left undone (5%). Nurses with a shorter employment history left care undone more frequently, and when the number of patients per nurse increased, the amount of care left undone increased as well. More than half of the participants (59%) considered work organisation to be the cause of care left undone.

Conclusions

Work organisation and staffing in surgical wards require more attention at the management level, as nursing care left undone occurred to a significant degree in the investigated wards, and more than half of the nurses considered work organisation to be the reason for care left undone.
Molecular Dynamic Simulation of Micro-Structured Diamond Tool in Silicon Carbide Cutting
Authors: Liu Changlin , Chu Jianning , Ke Jinyang , Chen Xiao , Zhang Jianguo , Xiao Junfeng , Xu Jianfeng
Published: April 2021

Silicon carbide (SiC) is an important material in many industrial applications. However, due to the hardness and brittleness nature, achieving ultraprecision machining of SiC is still challenging. In recent years, function surface with microstructures has been introduced in cutting tool to suppress wear process. But the wear mechanism of the structured tool has not been revealed completely. Therefore, in present research, molecular dynamic simulations were conducted to investigate the cutting performance of the microstructure on the nanoscale cutting process of 3 C-SiC. The simulation results showed that the dislocation propagation in workpiece can be suppressed with a structured tool. The microstructures have a significant influence on the stress distribution in the workpiece subsurface. Furthermore, the abrasive wear of the structured tool is obvious smaller since the edges of the tool became blunt and the contact face between tool and workpiece changed to the close-packed plane of diamond. Moreover, the amorphization of the structured tool is effectively suppressed. This study contributes to the understanding of the material behavior involved in the ultraprecision cutting of SiC.
Flow of Power-Law Fluids Past a Rotating Cylinder at High Reynolds Numbers
Authors: Thakur Pooja , Tiwari Naveen , Chhabra R. P.
Published: April 2021

In this study, a rotating cylinder is placed in a stream of shear-thinning fluids, flowing with a uniform velocity. Detailed investigations are performed for the following range of conditions: Reynolds number 100≤Re≤500, power-law index 0.2≤n≤1 and rotational velocity 0≤α≤5. Flow transitions are observed from steady to unsteady at critical values of the Reynolds number, the rotational velocity, and the power-law index. Critical values of the Reynolds number Rec have been obtained for varying levels of the rotational velocity, and the power-law index. Rec varies nonmonotonically with the rotational velocity. At a particular Reynolds number, an increase of the rotational velocity acts as a vortex suppression technique. For shear-thinning fluids considered here, the vortex suppression occurs at a larger value of the critical rotational velocity αc, relative to Newtonian fluids. For the unsteady flow, the lift coefficient versus time curve exhibits oscillatory behavior, and this has been used to delineate the flow regime as steady or unsteady flow. For unsteady flow regimes, both the amplitude of the lift coefficient and the Strouhal number increase with increasing Reynolds numbers. The results presented in this work for such high Reynolds numbers elucidate the possible complex interplay between the kinematic and rheological parameters of non-Newtonian fluids. This investigation also complements the currently available low Reynolds number results up to ∼ Re=140.
AN EXPERIMENTALLY VALIDATED LOW ORDER MODEL OF THE THERMAL RESPONSE OF DOUBLE-WALL EFFUSION COOLING SYSTEMS FOR HP TURBINE BLADES
Authors: Murray Alexander V , Ireland Peter , Romero Eduardo
Published: April 2021

Transpiration cooling represents the pinnacle of turbine cooling and is characterised by an intrinsic porosity achieving high internal convective cooling, and full coverage film cooling. The quasi-transpiration, double-wall effusion system attempts to replicate the cooling effect of transpiration cooling. The system is characterised by a large wetted area providing high internal convective cooling performance, with a highly porous external wall allowing the formation of a protective cooling film. This paper presents a low-order thermal model of a double-wall system designed to rapidly ascertain cooling performance based solely on the geometry, thermal conductivity, and approximate surface heat transfer coefficients. Initially validation uses experimental data with heat transfer coefficients for the low order model obtained from fully conjugate CFD simulations. A more controlled CFD study is then undertaken with both fully conjugate and fluid only simulations performed on several double-wall geometries to ascertain both overall and film effectiveness data. Data from these simulations are used as inputs to the low order thermal model and the results compared. The low order model successfully captures both the trends and absolute cooling effectiveness achieved by the various double-wall geometries. The model therefore provides a powerful tool whereby the cooling performance of double-wall geometries can be near instantaneously predicted during the initial design stage, potentially allowing geometry optimisation to rapidly occur prior to more in-depth, costly and time-consuming analyses. This benefit is demonstrated via the implementation of the model with input boundary conditions obtained using empirical correlations.
Asymptotic Stability of the Sphere’s Rolling Equilibrium
Authors: Das Tuhin
Published: April 2021

The classical phenomenon of a sphere transitioning from sliding to rolling during its motion on a horizontal plane is investigated from a novel system theoretic perspective. Specifically, the transition is studied as a problem in stabilization, an approach not reported in the literature. The main contribution of this paper is in proving that pure rolling is an asymptotically stable equilibrium within the state-space of a sliding sphere. It is shown that the stabilization of this equilibrium from arbitrary initial conditions occurs through the natural interplay between the friction force and moment that result from sliding. Simulation results confirm the theoretical development. The stability analysis is extended to motion on an inclined plane.
Secular Trends in Physical Activity Among Immigrants in the United States, 2009–2018
Authors: Jung Myungjin , Kim Heontae , Ryu Seungho , Kang Minsoo
Published: April 2021

Background: The objective of this study was to evaluate secular trends in domain-specific physical activity in the immigrant population in the US between 2009 and 2018. Method: A secondary data analysis from the 2009–2018 National Health and Nutrition Examination Survey; a total of 7282 immigrants in the US were included in this analysis. All domain-specific physical activity was assessed by a self-reported questionnaire. Tests for linear trends were performed to examine the trends of each physical activity time using orthogonal polynomial coefficients. Physical activity trends were assessed by the whole group and the various subgroups. Results: Total physical activity showed an upward linear trend in female (Ptrend = .04) and young adult (Ptrend = .009) immigrants. Work-related physical activity showed an upward linear trend in young adult immigrants (Ptrend = .01). Recreational physical activity showed an upward linear trend in young adult (Ptrend = .03) and Mexican American (Ptrend < .001) immigrants and in immigrants living in the US for 15–29 years (Ptrend = .02). In contrast, we observed downward linear trends in transit-related physical activity for immigrants across male (Ptrend = .04), middle-aged adult (Ptrend = .01), and non-Hispanic black groups (Ptrend = .004) and in immigrants living in the US for 15–29 years (Ptrend = .03). Conclusion: There were no significant linear trends in the 4 domains of physical activity in the overall US immigrant population; however, trends in domain-specific physical activity in the US immigrant population differed by gender, age, race/ethnicity, and length of residence. These findings may inform physical activity promotion strategies targeting US immigrant populations with diverse sociocultural backgrounds.
Peer-mediated HIV assisted partner services to identify and link to care HIV-positive and HCV-positive people who inject drugs: a cohort study protocol
Authors: Monroe-Wise Aliza , Mbogo Loice , Guthrie Brandon , Bukusi David , Sambai Betsy , Chohan Bhavna , Scott John , Cherutich Peter , Musyoki Helgar , Bosire Rose , Dunbar Matthew , Macharia Paul , Masyuko Sarah , Wilkinson Eduan , De Oliveira Tulio , Ludwig-Barron Natasha , Sinkele Bill , Herbeck Joshua , Farquhar Carey
Published: April 2021

Introduction

Targeted, tailored interventions to test high-risk individuals for HIV and hepatitis C virus (HCV) are vital to achieving HIV control and HCV microelimination in Africa. Compared with the general population, people who inject drugs (PWID) are at increased risk of HIV and HCV and are less likely to be tested or successfully treated. Assisted partner services (APS) increases HIV testing among partners of people living with HIV and improves case finding and linkage to care. We describe a study in Kenya examining whether APS can be adapted to find, test and link to HIV care the partners of HIV-positive PWID using a network of community-embedded peer educators (PEs). Our study also identifies HCV-positive partners and uses phylogenetic analysis to determine risk factors for onward transmission of both viruses.

Methods

This prospective cohort study leverages a network of PEs to identify 1000 HIV-positive PWID for enrolment as index participants. Each index completes a questionnaire and provides names and contact information of all sexual and injecting partners during the previous 3 years. PEs then use a stepwise locator protocol to engage partners in the community and bring them to study sites for enrolment, questionnaire completion and rapid HIV and HCV testing. Outcomes include number and type of partners per index who are mentioned, enrolled, tested, diagnosed with HIV and HCV and linked to care.

Ethics and dissemination

Potential index participants are screened for intimate partner violence (IPV) and those at high risk are not eligible to enrol. Those at medium risk are monitored for IPV following enrolment. A community advisory board engages in feedback and discussion between the community and the research team. A safety monitoring board discusses study progress and reviews data, including IPV monitoring data. Dissemination plans include presentations at quarterly Ministry of Health meetings, local and international conferences and publications.

Trial registration number

NCT03447210, Pre-results stage.
Implementing the US Department of Health and Human Services definition of multimorbidity: a comparison between billing codes and medical record review in a population-based sample of persons 40–84 years old
Authors: St Sauver Jennifer L , Chamberlain Alanna M , Bobo William V , Boyd Cynthia M , Finney Rutten Lila J , Jacobson Debra J , McGree Michaela E , Grossardt Brandon R , Rocca Walter A
Published: April 2021

Objective

To assess the validity of the US Department of Health and Human Services (DHHS) definition of multimorbidity using International Classification of Diseases, ninth edition (ICD-9) codes from administrative data.

Design

Cross-sectional comparison of two ICD-9 billing code algorithms to data abstracted from medical records.

Setting

Olmsted County, Minnesota, USA.

Participants

An age-stratified and sex-stratified random sample of 1509 persons ages 40–84 years old residing in Olmsted County on 31 December 2010.

Study measures

Seventeen chronic conditions identified by the US DHHS as important in studies of multimorbidity were identified through medical record review of each participant between 2006 and 2010. ICD-9 administrative billing codes corresponding to the 17 conditions were extracted using the Rochester Epidemiology Project records-linkage system. Persons were classified as having each condition using two algorithms: at least one code or at least two codes separated by more than 30 days. We compared the ICD-9 code algorithms with the diagnoses obtained through medical record review to identify persons with multimorbidity (defined as ≥2, ≥3 or ≥4 chronic conditions).

Results

Use of a single code to define each of the 17 chronic conditions resulted in sensitivity and positive predictive values (PPV) ≥70%, and in specificity and negative predictive values (NPV) ≥70% for identifying multimorbidity in the overall study population. PPV and sensitivity were highest in persons 65–84 years of age, whereas NPV and specificity were highest in persons 40–64 years. The results varied by condition, and by age and sex. The use of at least two codes reduced sensitivity, but increased specificity.

Conclusions

The use of a single code to identify each of the 17 chronic conditions may be a simple and valid method to identify persons who meet the DHHS definition of multimorbidity in populations with similar demographic, socioeconomic, and health care characteristics.
Untangling the inter-relatedness within integrated care programmes for community-dwelling frail older people: a rapid realist review
Authors: Ahmed Anam , van den Muijsenbergh Maria E T C , Mewes Janne C , Wodchis Walter P , Vrijhoef Hubertus J M
Published: April 2021

Objective

To identify the relationships between the context in which integrated care programmes (ICPs) for community-dwelling frail older people are applied, the mechanisms by which the programmes do (not) work and the outcomes resulting from this interaction by establishing a programme theory.

Design

Rapid realist review.

Inclusion criteria

Reviews and meta-analyses (January 2013–January 2019) and non-peer-reviewed literature (January 2013–December 2019) reporting on integrated care for community-dwelling frail older people (≥60 years).

Analysis

Selection and appraisal of documents was based on relevance and rigour according to the Realist And Meta-narrative Evidence Syntheses: Evolving Standards criteria. Data on context, mechanisms, programme activities and outcomes were extracted. Factors were categorised into the five strategies of the WHO framework of integrated people-centred health services (IPCHS).

Results

27 papers were included. The following programme theory was developed: it is essential to establish multidisciplinary teams of competent healthcare providers (HCPs) providing person-centred care, closely working together and communicating effectively with other stakeholders. Older people and informal caregivers should be involved in the care process. Financial support, efficient use of information technology and organisational alignment are also essential. ICPs demonstrate positive effects on the functionality of older people, satisfaction of older people, informal caregivers and HCPs, and a delayed placement in a nursing home. Heterogeneous effects were found for hospital-related outcomes, quality of life, healthcare costs and use of healthcare services. The two most prevalent WHO-IPCHS strategies as part of ICPs are ‘creating an enabling environment’, followed by ‘strengthening governance and accountability’.

Conclusion

Currently, most ICPs do not address all WHO-IPCHS strategies. In order to optimise ICPs for frail older people the interaction between context items, mechanisms, programme activities and the outcomes should be taken into account from different perspectives (system, organisation, service delivery, HCP and patient).
Gender inequality and the double burden of disease in low-income and middle-income countries: an ecological study
Authors: van der Ham Mirte , Bolijn Renee , de Vries Alcira , Campos Ponce Maiza , van Valkengoed Irene G M
Published: April 2021

Introduction

Many low-income and middle-income countries (LMIC) suffer from a double burden of infectious diseases (ID) and non-communicable diseases (NCD). Previous research suggests that a high rate of gender inequality is associated with a higher ID and NCD burden in LMIC, but it is unknown whether gender inequality is also associated with a double burden of disease. In this ecological study, we explored the association between gender inequality and the double burden of disease in LMIC.

Methods

For 108 LMIC, we retrieved the Gender Inequality Index (GII, scale 0–1) and calculated the double burden of disease, based on disability-adjusted life-years for a selection of relevant ID and NCD, using WHO data. We performed logistic regression analysis to study the association between gender inequality and the double burden of disease for the total population, and stratified for men and women. We adjusted for income, political stability, type of labour, urbanisation, government health expenditure, health infrastructure and unemployment. Additionally, we conducted linear regression models for the ID and NCD separately.

Results

The GII ranged from 0.13 to 0.83. A total of 37 LMIC had a double burden of disease. Overall, the adjusted OR for double burden of disease was 1.05 per 0.01 increase of GII (95% CI 0.99 to 1.10, p=0.10). For women, there was a borderline significant positive association between gender inequality and double burden of disease (OR 1.05, 95% CI 1.00 to 1.11, p=0.06), while there was no association in men (OR 0.99, 95% CI 0.95 to 1.04, p=0.75).

Conclusion

We found patterns directing towards a positive association between gender inequality and double burden of disease, overall and in women. This finding suggests the need for more attention for structural factors underlying gender inequality to potentially reduce the double burden of disease.
Reducing time to differentiated service delivery for newly diagnosed people living with HIV in Kigali, Rwanda: study protocol for a pilot, unblinded, randomised controlled study
Authors: Ross Jonathan , Murenzi Gad , Hill Sarah , Remera Eric , Ingabire Charles , Umwiza Francine , Munyaneza Athanase , Muhoza Benjamin , Habimana Dominique Savio , Mugwaneza Placidie , Zhang Chenshu , Yotebieng Marcel , Anastos Kathryn
Published: April 2021

Introduction

Current HIV guidelines recommend differentiated service delivery (DSD) models that allow for fewer health centre visits for clinically stable people living with HIV (PLHIV). Newly diagnosed PLHIV may require more intensive care early in their treatment course, yet frequent appointments can be burdensome to patients and health systems. Determining the optimal parameters for defining clinical stability and transitioning to less frequent appointments could decrease patient burden and health system costs. The objectives of this pilot study are to explore the feasibility and acceptability of (1) reducing the time to DSD from 12 to 6 months after antiretroviral therapy (ART) initiation,and (2) reducing the number of suppressed viral loads required to enter DSD from two to one.

Methods and analyses

The present study is a pilot, unblinded trial taking place in three health facilities in Kigali, Rwanda. Current Rwandan guidelines require PLHIV to be on ART for ≥12 months with two consecutive suppressed viral loads in order to transition to less frequent appointments. We will randomise 90 participants to one of three arms: entry into DSD at 6 months after one suppressed viral load (n=30), entry into DSD at 6 months after two suppressed viral loads (n=30) or current standard of care (n=30). We will measure feasibility and acceptability of this intervention; clinical outcomes include viral suppression at 12 months (primary outcome) and appointment attendance (secondary outcome).

Ethics and dissemination

This clinical trial was approved by the institutional review board of Albert Einstein College of Medicine and by the Rwanda National Ethics Committee. Findings will be disseminated through conferences and peer-reviewed publications, as well as meetings with stakeholders.

Trial registration number

NCT04567693.
Acceptability of intravitreal injections in geographic atrophy: protocol for a mixed-methods pilot study
Authors: Enoch Jamie , Ghulakhszian Arevik , Crabb David P , Dinah Christiana , Taylor Deanna J
Published: April 2021

Introduction

Age-related macular degeneration (AMD) is a common cause of visual impairment, affecting central vision. Geographic atrophy (GA) is an advanced form of the non-neovascular (dry) type of AMD. Late-stage clinical trials suggest that intravitreal injections of novel therapeutics may slow down the rate of GA progression by up to 30% in 1 year, thus allowing people with GA to preserve central vision for a longer period. While intravitreal injections have become an established treatment modality for neovascular (wet) AMD, it is unknown whether patients with (more gradually progressing) GA would accept regular injections that slow down, but do not stop or reverse, vision loss. Therefore, this mixed-methods pilot study will aim to explore whether regular intravitreal injections will be acceptable as treatment for patients with GA, and the factors that may affect treatment acceptability.

Methods and analysis

A mixed-methods survey has been designed in collaboration with a GA patient advisory group. The survey comprises of structured questionnaires, semi-structured interview questions regarding patients’ perceptions of intravitreal injections and the burden of treatment, and a task eliciting preferences between different potential treatments. Due to COVID-19 restrictions, this study will be conducted remotely by telephone. Thirty individuals will be recruited from NHS Medical Retina clinics at Central Middlesex Hospital, London. Half of the participants will be naïve to intravitreal injections, while half will have previous experience of intravitreal injections for neovascular (wet) AMD. Qualitative data analysis will be conducted using the Framework Method of analysis to identify key themes from participants’ accounts.

Ethics and dissemination

The study received Health Research Authority approval on 23 March 2021 (IRAS Project ID: 287824). Findings will be disseminated through peer-reviewed publications and conference presentations to the medical retina community, as well as through dialogue with patients and macular disease charities.
Nationwide seroprevalence of antibodies to SARS-CoV-2 in asymptomatic population in South Korea: a cross-sectional study
Authors: Nah Eun-Hee , Cho Seon , Park Hyeran , Hwang Inhwan , Cho Han-Ik
Published: April 2021

Objective

Asymptomatic active infection might be an important contributor to the COVID-19 outbreak. Serological tests can assess the extent of exposure and herd immunity to COVID-19 in general populations. This study aimed to estimate the nationwide seroprevalence of SARS-CoV-2 antibodies according to age, sex and clinical status in South Korea.

Design, setting and participants

This cross-sectional study randomly selected health examinees who underwent health check-up at 16 health promotion centres in 13 Korean cities across the country between late September and early December 2020. Residual serum samples were obtained from 4085 subjects (2014 men and 2071 women). Antibodies to SARS-CoV-2 were measured by electrochemiluminescence immunoassay using Elecsys Anti-SARS-CoV-2 (Roche Elecsys, Mannheim, Germany).

Primary and secondary outcome measures

Fisher’s exact test was used to compare the seroprevalence according to sex, age group and region. The relative risks of being seropositive according to the characteristics of the study subjects were analysed using logistic regression analysis.

Results

The overall seroprevalence of anti-SARS-CoV-2 was 0.39% (95% CI=0.20% to 0.58%): 0.30% (95% CI=0.06% to 0.54%) for men and 0.48% (95% CI=0.18% to 0.78%) for women. The rate of anti-SARS-CoV-2 positivity varied significantly between different regions of Korea (p=0.003), but not with age group, sex, or the statuses of obesity, diabetes, hypertension or smoking.

Conclusions

Most of the Korean population is still immunologically vulnerable to SARS-CoV-2, but the seroprevalence has increased relative to that found in studies performed prior to September 2020 in Korea.