bluuebunny/crossref_metadata_2025 huggingface dataset:
Aucubin ameliorates the LPS‐induced inflammatory response in bovine endometrial epithelial cells by inhibiting NF‐κB and activating the Keap1/Nrf2 signalling pathway
Authors: Gao Feng , Li Huatao , Feng Yanni , Tian Wenru , Cao Rongfeng , Fu Kaiqiang
Published: April 2021

Cows are susceptible to pathogenic bacterial infection after pregnancy, leading to inflammation of the endometrium. Aucubin (AU) has been proven to exhibit highly effective anti‐inflammatory activity, but its ability to protect against endometritis in dairy cows remains unclear. Therefore, the goal of the present study was to evaluate the protective effect of AU on the LPS‐induced inflammatory response of bovine endometrial epithelial cells (BEECs). After pre‐treating BEECs with AU (10, 20 and 50 μM) for 6 hr, the cells were stimulated with LPS for 3 hr. Subsequently, BEECs apoptosis was analysed by flow cytometry, the expression of pro‐inflammatory cytokine mRNA was detected by qRT‐PCR, and changes in NF‐κB and Keap1/Nrf2 signalling were analysed by western blotting and immunofluorescence analyses. The results showed that AU can reduce TNF‐α, IL‐1β, IL‐6, COX‐2 and iNOS mRNA expression in BEECs and reduce cell apoptosis. Furthermore, AU significantly reduced the level of NF‐κB p65 and IκB phosphorylation and inhibited the nuclear translocation of NF‐κB p65. AU also activated the Keap1/Nrf2 pathway, promoting the nuclear transfer of Nrf2 and increasing Keap1, Nrf2, HO‐1 and NQO1 mRNA and protein levels. Taken together, these results indicate that AU ameliorates the LPS‐induced inflammatory response by inhibiting NF‐κB and activating the Keap1/Nrf2 signalling pathway, which has a protective effect on BEECs.
Detection of BK polyomavirus genotypes to predict the development of BK polyomavirus‐associated complications in kidney transplant recipients: A retrospective analysis
Authors: Muñoz‐Gallego Irene , Díaz‐Madridano Nerea , Moral Noelia , Pascual Consuelo , Polanco Natalia , González Esther , Andrés Amado , Folgueira María Dolores
Published: April 2021

Objectives

This study focused on the role that BK polyomavirus (BKPyV) genotypes can play in the development of BKPyV‐associated complications in renal transplant recipients.

Methods

A retrospective observational study (January 2015 to April 2018) was conducted by analyzing BKPyV genotypes in 180 blood samples with detectable BKPyV viral load (VL) > 1000 copies/mL, from 63 renal transplant recipients. VL and BKPyV genotypes detections were based on real‐time PCR (rt‐PCR)‐specific assays.

Results

Forty‐four patients (44/63 [69.8%]) were men, and the median age was 55.0 (interquartile range 49.0‐66.0 years). Eleven patients had clinical manifestations (11/63 [17.5%]). The most frequently detected genotypes were I (14/63 [22.2%]) and II (13/63 [20.6%]). Half of the patients (33/63 [52.4%]) had a mixed genotype, most with genotypes I and II (25/33 [75.8%]). Patients with infection by mixed genotypes showed VLs that were detected earlier (in the first year after transplantation) than those with a single genotype (25/33 [75.8%] vs 13/30 [43.3%], P = .009) and demonstrated greater risk of developing clinical manifestations associated with BKPyV (odds ratio 12.609, 95% confidence interval 1.503‐105.807). Moreover, patients with first BKPyV VL > 10 000 copies/mL more frequently presented mixed genotypes (12/16 [75.0%] vs 21/47 [44.7%], P = .036).

Conclusions

The probability of developing clinical manifestations is higher in infections by mixed genotypes. Therefore, the detection of BKPyV genotypes by rt‐PCR can provide relevant information to stratify patients' risk of BKPyV‐associated complications and guide the clinical management of BKPyV infection in kidney transplant recipients.
Cytomegalovirus events in high‐risk allogeneic hematopoietic‐cell transplantation patients who received letermovir prophylaxis
Authors: Chen Kaiwen , Arbona‐Haddad Esther , Cheng Matthew P. , McDonnell Anne M. , Gooptu Mahasweta , Orejas Jose L. , Timblin Kaitlyn , Silverman Emily , Al‐Hamed Rama , Soiffer Robert J. , Hammond Sarah P. , Marty Francisco M.
Published: April 2021

Letermovir is approved for the prevention of cytomegalovirus (CMV) reactivation and clinical disease in patients undergoing allogeneic hematopoietic‐cell transplantation (HCT). However, there is uncertainty about letermovir's ability to prevent clinical events during the period of prophylaxis as well as after the discontinuation of prophylaxis in the post‐transplant setting. We performed a retrospective cohort study in CMV‐seropositive allogeneic HCT recipients at high risk of CMV events, who received letermovir for primary prophylaxis from November 2017 through December 2019. We analyzed CMV outcomes for these patients during and after prophylaxis was discontinued. Patient outcomes were followed through June 2020. Sixty patients received letermovir for a median of 13 weeks (range, 1‐72 weeks). Thirteen (22%) patients had quantifiable CMV DNAemia (reactivation) during letermovir prophylaxis a median of 9 days (range, 1‐59 days) after starting letermovir. Five (8%) of these patients discontinued prophylaxis and received preemptive therapy (PET) with valganciclovir; eight (13%) continued letermovir as prophylaxis and CMV DNAemia resolved without PET. Thirteen patients (22%) had post‐prophylaxis CMV reactivation a median of 33 days (range, 14‐109 days) after letermovir discontinuation. In four (7%) of these patients, CMV DNAemia resolved without PET, and nine (15%) received PET. No patient developed CMV disease. Patients who developed CMV reactivation during prophylaxis did so shortly after initiation of letermovir, and most patients who developed CMV reactivation post‐prophylaxis did so within 60 days after discontinuation of letermovir. Letermovir prophylaxis has changed the presentation of CMV infection in high‐risk HCT patients.
Relationship between symptoms, barriers to care and healthcare utilisation among children under five in rural Mali
Authors: Treleaven Emily , Whidden Caroline , Cole Faith , Kayentao Kassoum , Traoré Mohamed Bana , Diakité Djoumé , Sidibé Seydou , Lin Tracy Kuo , Boettiger David , Cissouma Souleymane , Sanogo Vincent , Padian Nancy , Johnson Ari , Liu Jenny
Published: April 2021

Objectives

To identify social and structural barriers to timely utilisation of qualified providers among children under five years in a high‐mortality setting, rural Mali and to analyse how utilisation varies by symptom manifestation.

Methods

Using baseline household survey data from a cluster‐randomised trial, we assessed symptom patterns and healthcare trajectories of 5117 children whose mothers reported fever, diarrhoea, bloody stools, cough and/or fast breathing in the preceding two weeks. We examine associations between socio‐demographic factors, symptoms and utilisation outcomes in mixed‐effect logistic regressions.

Results

Almost half of recently ill children reported multiple symptoms (46.2%). Over half (55.9%) received any treatment, while less than one‐quarter (21.7%) received care from a doctor, nurse, midwife, trained community health worker or pharmacist within 24 h of symptom onset. Distance to primary health facility, household wealth and maternal education were consistently associated with better utilisation outcomes. While children with potentially more severe symptoms such as fever and cough with fast breathing or diarrhoea with bloody stools were more likely to receive any care, they were no more likely than children with fever to receive timely care with a qualified provider.

Conclusions

Even distances as short as 2–5 km significantly reduced children’s likelihood of utilising healthcare relative to those within 2 km of a facility. While children with symptoms indicative of pneumonia and malaria were more likely to receive any care, suggesting mothers and caregivers recognised potentially severe illness, multiple barriers to care contributed to delays and low utilisation of qualified providers, illustrating the need for improved consideration of barriers.
Amplification dynamics of miniature inverted‐repeat transposable elements and their impact on rice trait variability
Authors: Castanera Raúl , Vendrell‐Mir Pol , Bardil Amélie , Carpentier Marie‐Christine , Panaud Olivier , Casacuberta Josep M.
Published: April 2021

Transposable elements (TEs) are a rich source of genetic variability. Among TEs, miniature inverted‐repeat TEs (MITEs) are of particular interest as they are present in high copy numbers in plant genomes and are closely associated with genes. MITEs are deletion derivatives of class II transposons, and can be mobilized by the transposases encoded by the latter through a typical cut‐and‐paste mechanism. However, MITEs are typically present at much higher copy numbers than class II transposons. We present here an analysis of 103 109 transposon insertion polymorphisms (TIPs) in 738 Oryza sativa genomes representing the main rice population groups. We show that an important fraction of MITE insertions has been fixed in rice concomitantly with its domestication. However, another fraction of MITE insertions is present at low frequencies. We performed MITE TIP‐genome‐wide association studies (TIP‐GWAS) to study the impact of these elements on agronomically important traits and found that these elements uncover more trait associations than single nucleotide polymorphisms (SNPs) on important phenotypes such as grain width. Finally, using SNP‐GWAS and TIP‐GWAS we provide evidence of the replicative amplification of MITEs.
An Arabidopsis lipid map reveals differences between tissues and dynamic changes throughout development
Authors: Kehelpannala Cheka , Rupasinghe Thusitha , Pasha Asher , Esteban Eddi , Hennessy Thomas , Bradley David , Ebert Berit , Provart Nicholas J. , Roessner Ute
Published: April 2021

Mass spectrometry is the predominant analytical tool used in the field of plant lipidomics. However, there are many challenges associated with the mass spectrometric detection and identification of lipids because of the highly complex nature of plant lipids. Studies into lipid biosynthetic pathways, gene functions in lipid metabolism, lipid changes during plant growth and development, and the holistic examination of the role of plant lipids in environmental stress responses are often hindered. Here, we leveraged a robust pipeline that we previously established to extract and analyze lipid profiles of different tissues and developmental stages from the model plant Arabidopsis thaliana. We analyzed seven tissues at several different developmental stages and identified more than 200 lipids from each tissue analyzed. The data were used to create a web‐accessible in silico lipid map that has been integrated into an electronic Fluorescent Pictograph (eFP) browser. This in silico library of Arabidopsis lipids allows the visualization and exploration of the distribution and changes of lipid levels across selected developmental stages. Furthermore, it provides information on the characteristic fragments of lipids and adducts observed in the mass spectrometer and their retention times, which can be used for lipid identification. The Arabidopsis tissue lipid map can be accessed at http://bar.utoronto.ca/efp_arabidopsis_lipid/cgi‐bin/efpWeb.cgi.
The novel pathogen‐responsive glycosyltransferase UGT73C7 mediates the redirection of phenylpropanoid metabolism and promotes SNC1‐dependent Arabidopsis immunity
Authors: Huang Xu‐Xu , Wang Yong , Lin Ji‐Shan , Chen Lu , Li Yan‐Jie , Liu Qian , Wang Guan‐Feng , Xu Fang , Liu Lijing , Hou Bing‐Kai
Published: April 2021

Recent studies have shown that global metabolic reprogramming is a common event in plant innate immunity; however, the relevant molecular mechanisms remain largely unknown. Here, we identified a pathogen‐induced glycosyltransferase, UGT73C7, that plays a critical role in Arabidopsis disease resistance through mediating redirection of the phenylpropanoid pathway. Loss of UGT73C7 function resulted in significantly decreased resistance to Pseudomonas syringae pv. tomato DC3000, whereas constitutive overexpression of UGT73C7 led to an enhanced defense response. UGT73C7‐activated immunity was demonstrated to be dependent on the upregulated expression of SNC1, a Toll/interleukin 1 receptor‐type NLR gene. Furthermore, in vitro and in vivo assays indicated that UGT73C7 could glycosylate p‐coumaric acid and ferulic acid, the upstream metabolites in the phenylpropanoid pathway. Mutations that lead to the loss of UGT73C7 enzyme activities resulted in the failure to induce SNC1 expression. Moreover, glycosylation activity of UGT73C7 resulted in the redirection of phenylpropanoid metabolic flux to biosynthesis of hydroxycinnamic acids and coumarins. The disruption of the phenylpropanoid pathway suppressed UGT73C7‐promoted SNC1 expression and the immune response. This study not only identified UGT73C7 as an important regulator that adjusts phenylpropanoid metabolism upon pathogen challenge, but also provided a link between phenylpropanoid metabolism and an NLR gene.
Anaemia in elderly patients at discharge from intensive care and hospital
Authors: Sinha Romi , Hakendorf Paul , Sobieraj‐Teague Magdalena , Roxby David
Published: April 2021

Background and objectives

Anaemia is common in the elderly and is recognized as a risk factor for several adverse outcomes in older adults, including hospitalization, morbidity and mortality. The study aims were to examine the prevalence of anaemia in elderly patients at discharge from the intensive care unit (ICU) and hospital.

Materials and methods

Patient randomized under the INFORM trial and with an ICU admission were included. Two cohorts, Cohort 1 patients who were alive on discharge from ICU and Cohort 2 patients who were discharged alive from hospital to home. Prevalence of significant anaemia defined as haemoglobin levels, less than 100 g/l was measured at ICU and hospital discharge.

Results

Overall, 76·5% (683/893) of elderly admissions in Cohort 1 had a haemoglobin <100 g/l, and 44·1% (395/893) had a haemoglobin <90 g/l on ICU discharge. Nadir haemoglobin during ICU stay, length of stay in ICU and transfusion during ICU stay was associated with significant anaemia at ICU discharge. At hospital discharge, in Cohort 2, 54·8% (263/480) of elderly ICU admissions had Hb < 100 g/l, and 23·4% (112/480) had Hb < 90 g/l. Male gender, haemoglobin level at ICU discharge, and length of stay and nadir Hb between ICU and hospital discharge were associated with anaemia at hospital discharge.

Conclusions

Significant anaemia is highly prevalent in elderly patients on discharge from ICU and to a lesser degree at hospital discharge.
Proteinase‐activated receptor‐2 (PAR2) on blood pressure and electrolyte handling in the late pregnant rat
Authors: West David A. , Beck Steven D. , de Souza Aline M. A. , West Crystal A.
Published: April 2021

New Findings

What is the central question of this study?

Pregnancy requires marked renal sodium and potassium retention and cumulative plasma volume expansion, in the setting of reduced blood pressure. Research in male rodents has shown that activation of PAR2 can produce peripheral vasodilatation, stimulate renal sodium chloride reabsorption and inhibit renal potassium secretion. Here, we investigate PAR2 activation in virgin and normal pregnant rats.

What is the main finding and its importance?

PAR2 expression and sensitivity to activation are increased in pregnancy. This implicates a possible role for PAR2 in supporting the renal/vascular adaptations of pregnancy required for normal maternal plasma volume expansion.

A healthy pregnancy involves renal and systemic haemodynamic adaptations, which allow renal sodium and potassium retention and cumulative plasma volume expansion, accompanied by a decline in blood pressure attributable to a reduction in the total peripheral vascular resistance. When these adaptations do not occur, pregnancy is compromised. The mechanisms permitting these opposing adaptations are largely unknown. Research in male rodents has shown that activation of PAR2 can produce peripheral vasodilatation, stimulate renal sodium chloride reabsorption and inhibit renal potassium secretion. Here, we investigate PAR2 activation in female virgin and normal late pregnant (LP) rats. We measured the mRNA expression of PAR2 in the renal cortex, outer medulla and inner medulla of virgin and LP rats using quantitative real‐time PCR. We also measured in vivo blood pressure, natriuretic and kaliuretic responses to PAR2‐activating peptide (SLIGRL‐NH2) in anaesthetized virgin and LP rats. We found that PAR2 mRNA was increased in the inner medulla of LP rats. We also found that LP rats had larger decreases in blood pressure and increases in net sodium retention compared with virgin rats. These findings suggest that pregnancy enhances sensitivity to the blood pressure‐lowering and sodium‐retaining effects of PAR2.
Effect of jump exercise training on long‐term head‐down bed rest‐induced cerebral blood flow responses in arteries and veins
Authors: Ogoh Shigehiko , Sato Kohei , de Abreu Steven , Denise Pierre , Normand Hervé
Published: April 2021

New Findings

What is the central question of this study?

What is the effect of an exercise countermeasure on microgravity‐induced change in cerebral blood flow?

What is the main finding and its importance?

Jump exercise training as a countermeasure did not modify the heterogeneous cerebral blood flow response to head‐down bed rest, suggesting that this method is effective in preventing cardiovascular system deconditioning but is not good for cerebral haemodynamics.

This study aimed to examine the effect of an exercise countermeasure on cerebral blood flow (CBF) response to long‐term −6° head‐down bed rest (HDBR) in all cerebral arteries and veins. Twenty male volunteers were exposed to HDBR for 60 days with (training group, n = 10) or without (control group, n = 10) jump exercise training as a countermeasure to spaceflight. The blood flow in the neck conduit arteries (internal carotid and vertebral artery; ICA and VA) and veins (internal jugular and vertebral veins; IJV and VV) was measured, using ultrasonography before (baseline) HDBR, on the 30th and 57th day of HDBR. Long‐term HDBR causes a heterogeneous CBF response between the anterior and the posterior brain or between arteries and veins. Long‐term HDBR decreased anterior cerebral arterial and venous blood flow, while posterior cerebral arterial and venous blood flows were well maintained. However, exercise jump training did not change each arterial and venous CBF responses to HDBR (control vs. training; ICA, P = 0.643; VA, P = 0.542; external carotid artery, P = 0.644; IJV, P = 0.980; VV, P = 0.999). These findings suggest that jump exercise training did not modify the heterogeneous CBF response to long‐term HDBR.
Bilateral regional extracranial blood flow regulation to hypoxia and unilateral duplex ultrasound measurement error
Authors: Friend Alexander T. , Rogan Matthew. , Rossetti Gabriella M. K. , Lawley Justin S. , Mullins Paul G. , Sandoo Aamer , Macdonald Jamie H. , Oliver Samuel J.
Published: April 2021

New Findings

What is the central question of this study?

Is blood flow regulation to hypoxia different between the internal carotid arteries (ICAs) and vertebral arteries (VAs), and what is the measurement error in unilateral extracranial artery assessments compared to bilateral?

What is the main finding and its importance?

ICA and VA blood flow regulation to hypoxia is comparable when factoring for vessel type and vessel side. Compared to bilateral assessment, vessels assessed unilaterally had individual measurement errors of up to 37%. Assessing the vessel with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error.

Whether blood flow regulation to hypoxia is similar between left and right internal carotid arteries (ICAs) and vertebral arteries (VAs) is unclear. Extracranial blood flow is regularly calculated by doubling a unilateral assessment; however, lateral artery differences may lead to measurement error. This study aimed to determine extracranial blood flow regulation to hypoxia when factoring for vessel type (ICAs or VAs) and vessel side (left or right) effects, and to investigate unilateral assessment measurement error compared to bilateral assessment. In a repeated‐measures crossover design, extracranial arteries of 44 participants were assessed bilaterally by duplex ultrasound during 90 min of normoxic and poikilocapnic hypoxic (12.0% fraction of inspired oxygen) conditions. Linear mixed model analyses revealed no Condition × Vessel Type × Vessel Side interaction for blood flow, vessel diameter and flow velocity (all P > 0.05) indicating left and right ICA and VA blood flow regulation to hypoxia was similar. Bilateral hypoxic reactivity was comparable (ICAs, 1.4 (1.0) vs. VAs, 1.7 (1.1) Δ%·Δ−1; P = 0.12). Compared to bilateral assessment, unilateral mean measurement error of the relative blood flow response to hypoxia was up to 5%, but individual errors reached 37% and were greatest in ICAs and VAs with the smaller resting blood flow due to a ratio‐scaling problem. In conclusion, left and right ICA and VA regulation to hypoxia is comparable when factoring for vessel type and vessel side. Assessing the ICA and VA vessels with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error.
Association between cortical thickness and distinct vascular cognitive impairment and dementia in patients with white matter lesions
Authors: Liu Yafei , Hu Anming , Chen Luyao , Li Bo , Zhang Minjian , Xi Pengcheng , Yang Qinghu , Tang Rongyu , Huang Qiang , He Jiping , Lang Yiran , Zhang Yumei
Published: April 2021

New Findings

What is the central question of this study?

White matter lesions (WMLs) are a brain disease characterized by altered brain structural and functional connectivity, but findings have shown an inconsistent pattern: are there distinct cortical thickness changes in patients with WMLs subtypes?

What is the main finding and its importance?

Patients with WMLs with non‐dementia vascular cognitive impairment and WMLs with vascular dementia showed distinct pathophysiology in cortical thickness. These neural correlates of WMLs should be considered in future treatment.

The effect of cortical thickness on white matter lesions (WMLs) in patients with distinct vascular cognitive impairments is relatively unknown. This study investigated the correlation between cortical thickness and vascular cognitive manifestations. WML patients and healthy controls from Beijing Tiantan Hospital between 2014 and 2018 were included. The patients were further divided into two subgroups, namely WMLs with non‐dementia vascular cognitive impairment (WML‐VCIND) and WMLs with vascular dementia (WML‐VaD) according to the Clinical Dementia Rating (CDR) scale and the Beijing version of the Montreal Cognitive Assessment (MoCA). Changes in cortical thickness were calculated using FreeSurfer. Pearson's correlation analysis was performed to explore the relationship between cognitive manifestations and cortical thickness in WML patients. Forty‐five WML patients and 23 healthy controls were recruited. The WML group exhibited significant difference in cortical thickness compared to the control group. Significantly decreased cortical thickness in the middle and superior frontal gyri, middle temporal gyrus, angular gyrus and insula was found in the WML‐VaD versus WML‐VCIND subgroup. Cortical thickness deficits of the left caudal middle frontal gyrus (r = 0.451, P = 0.002), left rostral middle frontal gyrus (r = 0.514, P < 0.001), left superior frontal gyrus (r = 0.410, P = 0.006), right middle temporal gyrus (r = 0.440, P = 0.003), right pars triangularis (r = 0.462, P = 0.002), right superior frontal gyrus (r = 0.434, P = 0.004) and right insula (r = 0.499, P = 0.001) were positively correlated with the MoCA score in WML patients. The specific pattern of cortical thickness deficits in the WML‐VaD subgroup revealed the pathophysiology of WMLs, which should be considered in future treatment of WMLs.
The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta‐analysis
Authors: Pizzey Faith K. , Smith Emily C. , Ruediger Stefanie L. , Keating Shelley E. , Askew Christopher D. , Coombes Jeff S. , Bailey Tom G.
Published: April 2021

New Findings

What is the topic of this review?

We have conducted a systematic review and meta‐analysis on the current evidence for the effect of heat therapy on blood pressure and vascular function.

What advances does it highlight?

We found that heat therapy reduced mean arterial, systolic and diastolic blood pressure. We also observed that heat therapy improved vascular function, as assessed via brachial artery flow‐mediated dilatation. Our results suggest that heat therapy is a promising therapeutic tool that should be optimized further, via mode and dose, for the prevention and treatment of cardiovascular disease risk factors.

Lifelong sauna exposure is associated with reduced cardiovascular disease risk. Recent studies have investigated the effect of heat therapy on markers of cardiovascular health. We aimed to conduct a systematic review with meta‐analysis to determine the effects of heat therapy on blood pressure and indices of vascular function in healthy and clinical populations. Four databases were searched up to September 2020 for studies investigating heat therapy on outcomes including blood pressure and vascular function. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to assess the certainty of evidence. A total of 4522 titles were screened, and 15 studies were included. Healthy and clinical populations were included. Heat exposure was for 30–90 min, over 10–36 sessions. Compared with control conditions, heat therapy reduced mean arterial pressure [n = 4 studies; mean difference (MD): −5.86 mmHg, 95% confidence interval (CI): −8.63, −3.10;P < 0.0001], systolic blood pressure (n = 10; MD: −3.94 mmHg, 95% CI: −7.22, −0.67;P = 0.02) and diastolic blood pressure (n = 9; MD: −3.88 mmHg, 95% CI: −6.13, −1.63;P = 0.0007) and improved flow‐mediated dilatation (n = 5; MD: 1.95%, 95% CI: 0.14, 3.76;P = 0.03). Resting heart rate was unchanged (n = 10; MD: −1.25 beats/min; 95% CI: −3.20, 0.70;P = 0.21). Early evidence also suggests benefits for arterial stiffness and cutaneous microvascular function. The certainty of evidence was moderate for the effect of heat therapy on systolic and diastolic blood pressure and heart rate and low for the effect of heat therapy on mean arterial pressure and flow‐mediated dilatation. Heat therapy is an effective therapeutic tool to reduce blood pressure and improve macrovascular function. Future research should aim to optimize heat therapy, including the mode and dose, for the prevention and management of cardiovascular disease.
Analysis of an Integrated Thermal Energy System for Applications in Cold Regions
Authors: Addo-Binney Bismark , Besada Wahid , Agelin-Chaab Martin
Published: April 2021

This paper performed analyses on a proposed direct wind-powered heat pump integrated with a pond which serves as an evaporator for space heating in cold regions. The analysis was conducted using environmental data for selected locations in Canada and the engineering equation solver (EES). Three different pairings of heat pumps and wind turbines were studied (a wind-powered heat pump with a pond as an evaporator, wind-powered heat pump without a pond, and an electricity-powered heat pump (EPHP)). Energy and exergy analyses were performed on the systems. The novelty in the present study is in the use of a wind turbine to directly power the heat pump and using a pond as the evaporator. The results show that the proposed system has the highest coefficient of performance (COP) compared with the others. The average coefficient of performance for the selected locations is 2.7, which is at least 67% better than the others. Similarly, the overall exergy for the proposed system is 16.9%, which is at least 40% better than the others. The average heating capacity of the selected locations for the proposed system is 4.5 kW, which is from 29% to 300% better than the others. Additionally, the sustainability index (SI) for the proposed system is the highest for the proposed system. The results have shown that the proposed system has superior overall performance for space heating in cold regions.
On the Supercritical Carbon Dioxide Recompression Cycle
Authors: You Dongchuan , Metghalchi Hameed
Published: April 2021

Supercritical carbon dioxide (sCO2) Brayton cycle has been studied in recent years, and its high efficiency and environmental safety have been investigated. One of the most promising sCO2 designs is the Recompression cycle described in the Introduction of the paper. In this paper, an effort has been made to optimize the operation of a recompression cycle by performing parametric analyses on pressure ratio, split fraction, and maximum temperature. The effects of varying these parameters on thermal efficiency as well as exergetic efficiency have been determined.
Sea Spray Icing: The Physical Process and Review of Prediction Models and Winterization Techniques
Authors: Deshpande Sujay , Sæterdal Ane , Sundsbø Per-Arne
Published: April 2021

Ice accretion on marine vessels and offshore structures is a severe hazard in the Polar regions. There are increasing activities related to oil and gas exploration, tourism, cargo transport, and fishing in the Arctic. Ice accretion can cause vessel instability, excess load on marine structures, and represents a safety risk for outdoor working environment and operations. Freezing sea spray is the main contributor to marine icing. For safe operations in cold climates, it is essential to have verified models for the prediction of icing. Sea spray icing forecast models have improved. Empirical and theoretical models providing icing rates based may be useful as guidelines. For predicting the distribution of icing on a surface at the design stage, computational fluid dynamics has to be applied along with a freezing module. State-of-the-art models for numerical simulation of sea spray icing are still not fully capable of modeling complex ship-sea-wind interactions with spray generation and impact of shipped water. Existing models include a good understanding of spray flow effects and freezing. Further development should focus on developing models for dynamic ship-sea-wind interactions, in particular including spray generation, effects of shipped water, and distribution of icing on the vessel surface. More experimental and full-scale data are needed for the development and verification of new and improved models. Models that estimate ice distribution may improve the winterization design process and reduce the effort required for de-icing. Improved methods for de-icing and anti-icing will reduce the impact of sea spray icing and increase safety for marine operations in cold waters.
A Review of Ice Protection Techniques for Structures in the Arctic and Offshore Harsh Environments
Authors: Shi Kewei , Duan Xili
Published: April 2021

Icing can jeopardize local infrastructure, hinder field operation, destroy vessel superstructures, and threaten life and property safety in the Arctic and other cold offshore and marine environments. Research on ice protection (both anti-icing and de-icing) technologies is critical to equipment, structures, and personnel in these environments. This review systematically evaluates a wide range of ice protection techniques divided into three main categories, i.e., active, passive, and hybrid ice protection techniques. Active anti-icing/de-icing technologies include mechanical, thermal, or chemical methods, requiring an additional energy source to prevent ice formation or remove accumulated ice from the target surfaces. Passive anti-icing/de-icing techniques can prevent ice accumulation or reduce ice adhesion without external energy sources; they create and maintain the icephobic properties of the target surfaces. Excessive energy consumption is a major technical limitation of active ice protection technologies. On the other hand, it is challenging for any passive technology to meet the long-term ice protection requirements in the Arctic or different cold offshore/marine environments. A combination of two or more active and passive ice protection methods, i.e., a hybrid approach, seems promising and can be applied in various situations according to the specific requirements of different vessels, offshore structures, and equipment.
The Role of Surface Topography and Normal Load in the Initiation of Ratchetting-Peak Friction, Seizure, Scuffing, and Elastic Shakedown
Authors: Edachery Vimal , Swamybabu V. , Gurupatham Anand , Paramasamy Manikandan , Kailas Satish V.
Published: April 2021

Surface topography is a critical parameter that can influence friction and wear in engineering applications. In this study, the influence of surface topography directionality on seizure and scuffing initiation during tribological interactions is explored. Hence, unidirectional sliding wear experiments were carried out in immersed lubrication conditions for various normal loads. The tribological interactions were studied using EN31-60 HRC flats and SAE52100-60 HRC pins in a sphere on flat configuration. The results show that, in some cases, the sliding interactions in the initial cycles lead to a high friction coefficient of up to ∼0.68 in lubricated conditions, which was termed as “peak friction”, and this was accompanied by scuffing. The existence of peak friction was found to be dependent on surface topography directionality, especially when the directionality in topography was parallel to the sliding direction. Continuous ratchetting was found to be the cause of peak friction, which was accompanied by seizure and scuffing. When the topography directionality was perpendicular or independent of the sliding direction, elastic shakedown occurred at earlier cycles and prevented peak friction initiation and scuffing and also facilitated for higher steady-state friction values.
Bowen–York model solution redux
Authors: Altas Emel , Tekin Bayram
Published: April 2021

Initial value problem in general relativity is often solved numerically; with only a few exceptions one of which is the “model” solution of Bowen and York where an analytical form of the solution is available. The solution describes a dynamical, time-asymmetric, gravitating system with mass and linear momentum. Here we revisit this solution and correct an error which turns out to be important for identifying the energy-content of the solution. Depending on the linear momentum, the ratio of the non-stationary part of the initial energy to the total ADM energy takes values between [0, 0.592). This non-stationary part is expected to be turned into gravitational waves during the evolution of the system to possibly settle down to a black hole with mass and linear momentum. In the ultra-relativistic case (the high momentum limit), the maximum amount of gravitational wave energy is 59.2% of the total ADM energy. We also give a detailed account of the general solution of the Hamiltonian constraint.
A Proximal Bundle Method with Exact Penalty Technique and Bundle Modification Strategy for Nonconvex Nonsmooth Constrained Optimization
Authors: Wang Xiaoliang , Pang Liping , Wu Qi
Published: April 2021

The bundle modification strategy for the convex unconstrained problems was proposed by Alexey et al. [[2007] European Journal of Operation Research, 180(1), 38–47.] whose most interesting feature was the reduction of the calls for the quadratic programming solver. In this paper, we extend the bundle modification strategy to a class of nonconvex nonsmooth constraint problems. Concretely, we adopt the convexification technique to the objective function and constraint function, take the penalty strategy to transfer the modified model into an unconstrained optimization and focus on the unconstrained problem with proximal bundle method and the bundle modification strategies. The global convergence of the corresponding algorithm is proved. The primal numerical results show that the proposed algorithms are promising and effective.
Does additional weekend and holiday physiotherapy benefit geriatric patients with hip fracture? — A case-historical control study
Authors: Mo Dennis Kim Chung , Lau Ken Kin Ming , Fung Donna Mei Yee , Ma Bosco Hon Ming , Lau Titanic Fuk On , Law Sheung Wai
Published: April 2021

Objective: To evaluate the new service model of additional weekend and holiday physiotherapy (PT) by comparing functional outcomes and hospital length of stay between a group of geriatric patients with hip fracture receiving daily PT training and a group of geriatric patients with hip fracture receiving weekdays PT training.

Methods: A retrospective case-historical control chart review was conducted and a total of 355 patients were identified. Between-group comparisons were done on functional outcomes including Modified Functional Ambulation Classification (MFAC), Elderly Mobility Scale (EMS), Modified Barthel Index (MBI) and process outcome in terms of length of stay (LOS) in hospitals.

Results: With similar characteristics, patients who received weekend and holiday PT training had a significant higher percentage of MFAC Category III and a significant lower percentage of MFAC Category II ([Formula: see text]) and significant higher MBI scores ([Formula: see text] deviation, median; Study group: [Formula: see text] points, 51 points; Control group: [Formula: see text] points, 43 points; [Formula: see text]) upon admission to rehabilitation hospital. A similar trend in EMS scores (Study group: [Formula: see text] points, 7 points; Control group: [Formula: see text] points, 6 points; [Formula: see text]) and MBI scores (Study group: [Formula: see text] points, 68 points; Control group: [Formula: see text] points, 64 points; [Formula: see text]) were observed upon discharge from the rehabilitation hospital. The average LOS in acute hospitals remained static (Study group: [Formula: see text] days, 7 days; Control group: [Formula: see text] days, 6 days; [Formula: see text]). The average LOS in rehabilitation hospital (Study group: [Formula: see text] days, 20 days; Control group: [Formula: see text] days, 23 days; [Formula: see text]) and total in-patient LOS (Study group: [Formula: see text] days, 26 days; Control group: [Formula: see text] days, 28 days; [Formula: see text]) were significantly reduced. A higher percentage of days having PT training during hospitalization in rehabilitation hospital was shown with the implementation of new service (Study group: 89.1%; Control group: 65.9%, [Formula: see text]).

Conclusion: Additional weekend and holiday PT training in post-operative acute and rehabilitation hospitalization benefits geriatric patients with hip fracture in terms of improved training efficiency, where hospital LOS was shortened with more PT sessions, without any significant impacts on functional outcome.
Limiting potential COVID-19 contagion in squatting public toilets
Authors: Pan Li , Chen Shuang-Lan , Guo Yi-Sha , Du Yu-Xiang , Wu Xiao-Di , Jones Alice Y. M. , Han Jia
Published: April 2021

Background: Since the outbreak of the SARS-CoV-2 virus in December 2019, the COVID-19 pandemic continues to threaten global stability. Transmission of SARS-CoV-2 is mostly by respiratory droplets and direct contact but viral RNA fragments have also been detected in the faecal waste of patients with COVID-19. Cleanliness and effective sanitation of public toilets is a concern, as flushing the toilet is potentially an aerosol generating procedure. When the toilets are of the squatting type and without a cover, there exists a risk of viral contamination through the splashing of toilet water and aerosol generation.

Objective: This study aims to determine whether the cleanliness of public toilets was a concern to the general population during the COVID-19 pandemic, and whether a squatting toilet was preferred to a seated design.

Methods: A questionnaire was designed and posted on “WeChat” contact groups of the investigators.

Results: The survey showed that 91% of participants preferred squatting toilets, but that 72% were apprehensive of personal contamination when using public toilets. Over 63% of the respondents had encountered an incidence of water splash and would prefer public toilets to be covered during flushing and 83% of these respondents preferred a foot-controlled device.

Conclusion: This survey suggests that consideration should be given to the installation of a simple foot-controlled device to cover public squatting toilets to help restrict potential COVID-19 contamination and to meet hygienic expectations of the public.
A stochastic vaccinated epidemic model incorporating Lévy processes with a general awareness-induced incidence
Authors: Akdim Khadija , Ez-Zetouni Adil , Zahid Mehdi
Published: April 2021

In this paper, we investigate a stochastic vaccinated epidemic model with a general awareness-induced incidence perturbed by Lévy noise. First, we show that this model has a unique global positive solution. Therefore, we establish the dynamic behavior of the solution around both disease-free and endemic equilibrium points. Furthermore, when [Formula: see text], we give sufficient conditions for the existence of an ergodic stationary distribution to the model when the jump part in the Lévy noise is null. Finally, we present some examples to illustrate the analytical results by numerical simulations.
Global analysis of a juvenile-adult model for cannibalistic species
Authors: Li Xiong , Huang Qihua
Published: April 2021

Cannibalism is a life trait occurring in a wide variety of species. To describe the population dynamics of cannibalistic species, we develop a stage-structured population model in which adults prey on juveniles with a Holling type I functional response. We make a rigorous analysis of the global dynamics in the model. The results of theoretical analysis show that the model has no boundary equilibrium other than the extinction one since juveniles and adults are cooperative (adults reproduce juveniles and juveniles grow into adults). Under certain conditions, the model has multiple interior equilibria and exhibits several types of bistable dynamics, in which different initial densities of juveniles and adults produce different long-term outcomes.
Stability analysis of a fractional-order cancer model with chaotic dynamics
Authors: Naik Parvaiz Ahmad , Zu Jian , Naik Mehraj-ud-din
Published: April 2021

In this paper, we develop a three-dimensional fractional-order cancer model. The proposed model involves the interaction among tumor cells, healthy tissue cells and activated effector cells. The detailed analysis of the equilibrium points is studied. Also, the existence and uniqueness of the solution are investigated. The fractional derivative is considered in the Caputo sense. Numerical simulations are performed to illustrate the effectiveness of the obtained theoretical results. The outcome of the study reveals that the order of the fractional derivative has a significant effect on the dynamic process. Further, the calculated Lyapunov exponents give the existence of chaotic behavior of the proposed model. Also, it is observed from the obtained results that decrease in fractional-order [Formula: see text] increases the chaotic behavior of the model.
A co-infection model for HPV and syphilis with optimal control and cost-effectiveness analysis
Authors: Omame A. , Okuonghae D. , Nwafor U. E. , Odionyenma B. U.
Published: April 2021

A co-infection model for human papillomavirus (HPV) and syphilis with cost-effectiveness optimal control analysis is developed and presented. The full co-infection model is shown to undergo the phenomenon of backward bifurcation when a certain condition is satisfied. The global asymptotic stability of the disease-free equilibrium of the full model is shown not to exist when the associated reproduction number is less than unity. The existence of endemic equilibrium of the syphilis-only sub-model is shown to exist and the global asymptotic stability of the disease-free and endemic equilibria of the syphilis-only sub-model was established, for a special case. Sensitivity analysis is also carried out on the parameters of the model. Using the syphilis associated reproduction number, [Formula: see text], as the response function, it is observed that the five-ranked parameters that drive the dynamics of the co-infection model are the demographic parameter [Formula: see text], the effective contact rate for syphilis transmission, [Formula: see text], the progression rate to late stage of syphilis [Formula: see text], and syphilis treatment rates: [Formula: see text] and [Formula: see text] for co-infected individuals in compartments [Formula: see text] and [Formula: see text], respectively. Moreover, when the HPV associated reproduction number, [Formula: see text], is used as the response function, the five most dominant parameters that drive the dynamics of the model are the demographic parameter [Formula: see text], the effective contact rate for HPV transmission, [Formula: see text], the fraction of HPV infected who develop persistent HPV [Formula: see text], the fraction of individuals vaccinated against incident HPV infection [Formula: see text] and the HPV vaccine efficacy [Formula: see text]. Numerical simulations of the optimal control model showed that the optimal control strategy which implements syphilis treatment controls for singly infected individuals is the most cost-effective of all the control strategies in reducing the burden of HPV and syphilis co-infections.
Dynamical behavior of a stochastic multigroup staged-progression HIV model with saturated incidence rate and higher-order perturbations
Authors: Liu Qun , Jiang Daqing
Published: April 2021

In this paper, we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HIV with saturated incidence rate. We obtain sufficient conditions for the existence and uniqueness of an ergodic stationary distribution of positive solutions to the system by establishing a suitable stochastic Lyapunov function. In addition, we make up adequate conditions for complete eradication and wiping out the infectious disease. In a biological interpretation, the existence of a stationary distribution implies that the disease will prevail and persist in the long term. Finally, examples and numerical simulations are introduced to validate our theoretical results.
Dynamic analysis based on the relapse rate of drug epidemic model
Authors: Niu Lu , Wang Xiaoyun
Published: April 2021

In this paper, we study a drug epidemic model based on epidemiology by dividing the human population into four classes at time [Formula: see text]: susceptibles (S), drug users (I), drug users who are treated in isolation and temporarily quit drugs[Formula: see text] and drug users who are treated in isolation and permanently quit drugs [Formula: see text]. We obtain the basic reproduction number [Formula: see text] of the model and perform its sensitivity analysis. We show that if [Formula: see text], then the drug-free equilibrium is globally asymptotically stable, and if [Formula: see text], there exists an drug-abuse equilibrium and it is locally asymptotically stable. The proposed model may possess forward and backward bifurcations. Moreover, three different control strategies and numerical results are presented. Through different adjustments to obtain graphical results, we obtain the best strategy to control the drug epidemic.