Publications by authors named "Hallen J"

Cardiac output (Q̇) and leg blood flow (Q̇) can be measured simultaneously with high accuracy using transpulmonary and femoral vein thermodilution with a single-bolus injection. The invasive measure has offered important insight into leg hemodynamics and blood flow distribution during exercise. Despite being the natural modality of exercise in humans, there has been no direct measure of Q̇ while running in humans.

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Purpose: To determine the relationship between three postoperative physiotherapy activities (time to first postoperative walk, activity on the day after surgery, and physiotherapy frequency), and the outcomes of hospital length of stay (LOS) and discharge destination after hip fracture.

Methods: A cohort study was conducted on 437 hip fracture surgery patients aged ≥ 50 years across 36 participating hospitals from the Australian and New Zealand Hip Fracture Registry Acute Rehabilitation Sprint Audit during June 2022. Study outcomes included hospital LOS and discharge destination.

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Aim: To assess the impact of endurance training on skeletal muscle release of H and K.

Methods: Nine participants performed one-legged knee extension endurance training at moderate and high intensities (70%-85% of W), three to four sessions·week for 6 weeks. Post-training, the trained and untrained (control) leg performed two-legged knee extension at low, moderate, and high intensities (40%, 62%, and 83% of W) in normoxia and hypoxia (~4000 m).

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A recent advance in the study of emergent magnetic monopoles was the discovery that monopole motion is restricted to dynamical fractal trajectories [J. N. Hallén , , 1218 (2022)], thus explaining the characteristics of magnetic monopole noise spectra [R.

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Objective: The aim of this study was to examine temporal trends (2016-2020) in hip fracture care in Australian and New Zealand (ANZ) hospitals that started providing patient-level data to the ANZ Hip Fracture Registry (ANZHFR) on/before 1 January 2016 (early contributors).

Methods: Retrospective cohort study of early contributor hospitals (n = 24) to the ANZHFR. The study cohort included patients aged ≥50 years admitted with a low trauma hip fracture between 1 January 2016 and 31 December 2020 (n = 26,937).

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Objective: S100A4 is a DAMP protein. S100A4 is overexpressed in patients with systemic sclerosis (SSc), and levels correlate with organ involvement and disease activity. S100A4 mice are protected from fibrosis.

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Article Synopsis
  • The study examines how blood volume (BV) per kg of body mass (BM) may underestimate BV in individuals with high fat mass, particularly highlighting differences between sexes, ages, and fitness levels.* -
  • It was found that women had a lower BV/BM compared to men by 25%, but when adjusted for lean body mass (LBM), women showed a 6% higher BV/LBM.* -
  • Among athletes, BV/BM was 17.2% higher than non-athletes, but this difference shrank to only 2.5% when adjusted for LBM, indicating that LBM is a strong predictor of BV and hemoglobin mass (Hb) in clinical assessments.*
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Aims: Echocardiographic characteristics to distinguish physiological left ventricular (LV) hypertrophy from pathology are warranted in early adolescent athletes. This study aimed to explore the phenotype, progression, and potential grey zone of LV hypertrophy during adolescence in athletes and hypertrophic cardiomyopathy (HCM) genotype-positive patients.

Methods And Results: In this longitudinal observation study, we compared seventy-six 12-year-old athletes with 55 age-matched and sex-matched HCM genotype-positive patients.

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Introduction: Peak oxygen uptake (V̇O ) declines by ~7% per 1000 m of increasing altitude, whereas exercise performance seems reduced to a lesser extent. For example, 800-10 000 m track and field performances are decreased by 0.4%-2.

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Purpose: Maximal oxygen uptake (V̇O ) increases during adolescence parallel to the increase in fat-free mass (FFM). How much endurance training adds to this effect is still controversial. Our aim was to investigate if inclusion of high-intensity training (HIT) during an 8-week training period was superior to low-intensity strength and coordination training in 12-year-old youth athletes concerning the effect on V̇O .

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When high-intensity exercise is performed until exhaustion a "functional reserve" (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VOmax interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR.

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Objectives: We have studied the damage-associated molecular pattern protein S100A4 as a driver of fibroblast activation in systemic sclerosis (SSc).

Methods: S100A4 protein concentration was measured by ELISA in serum of SSc (n=94) and healthy controls (n=15). Protein expression in skin fibroblast cultures from diffuse cutaneous SSc (SScF, n=6) and healthy controls (normal fibroblasts (NF), n=6) was assessed.

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Objectives: Our previous studies have demonstrated that the Damage Associated Molecular Pattern (DAMP) protein, S100A4, is overexpressed in the involved skin and peripheral blood of patients with SSc. It is associated with skin and lung involvement, and disease activity. By contrast, lack of S100A4 prevented the development of experimental dermal fibrosis.

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Background: Anthracycline-based chemotherapy has been mainstay of adjuvant breast cancer therapy for decades. Although effective, anthracyclines place long-term breast cancer survivors at risk of late effects, such as reduced cardiorespiratory fitness and increased risk of cardiovascular disease. Previous research has shown beneficial effects of exercise training on cardiorespiratory fitness, but the effects of exercise on limiting factors for cardiorespiratory fitness, cardiovascular risk factors, and patient-reported outcomes in long-term survivors are less clear.

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Background: Athlete's heart is a condition of exercise-induced cardiac remodelling. Adult male endurance athletes more often remodel beyond reference values. The impact of sex on remodelling through adolescence remains unclear.

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Around 42.7% of women experience anaemia during pregnancy in low- and middle-income countries. Countries in southeast Asia (with prevalence ranging between 40 and 60%) have reported a modest decline over the past 25 years.

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Sediments polluted by historical emissions from anthropogenic point sources are common in industrialized parts of the world and pose a potential threat to the function of aquatic ecosystems. Gradient studies using fish as a bioindicator are an option to assess the ecological impact of locally polluted areas. This study investigates the remaining effects of historical emissions on sediments outside ten Swedish pulp and paper mills using perch (Perca fluviatilis).

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Cancer survivors suffer impairments in skeletal muscle in terms of reduced mass and function. Interestingly, human skeletal muscle possesses an epigenetic memory of earlier stimuli, such as exercise. Long-term retention of epigenetic changes in skeletal muscle following cancer survival and/or exercise training has not yet been studied.

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Fractals-objects with noninteger dimensions-occur in manifold settings and length scales in nature. In this work, we identify an emergent dynamical fractal in a disorder-free, stoichiometric, and three-dimensional magnetic crystal in thermodynamic equilibrium. The phenomenon is born from constraints on the dynamics of the magnetic monopole excitations in spin ice, which restrict them to move on the fractal.

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Unlabelled: Pharmacological management of bone health warrants investigation into factors influencing initiation of bone protection medication (BPM) at discharge after a hip fracture. This sprint audit identified reasons attributed to low BPM treatment levels at hospital discharge which can guide improvement in the prevention of future fractures.

Purpose: To compare patient characteristics and Australian and New Zealand approaches to prescribing bone protection medication (BPM) pre- or post-hip fracture, determine reasons why BPM was not prescribed earlier post-fracture, and assess the generalisability of sprint audit and the Australian and New Zealand Hip Fracture Registry (ANZHFR) patient cohorts.

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Aims: We aimed to study initiation, adherence, and long-term persistence to beta-blockers (BB), renin-angiotensin system inhibitors (RASi), and mineralocorticoid receptor antagonists (MRA) in a nationwide cohort of patients with heart failure (HF).

Methods: Patients aged 18-80 years in Norway with a first diagnosis of HF from 2014 until 2020 that survived ≥30 days were identified from the Norwegian Patient Registry and linked to the Norwegian Prescription Database. We collected information about BB, RASi [angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARB), and angiotensin receptor-neprilysin inhibitors (ARNI)], and MRA.

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Two heat treatments were carried out at below (Ti6Al4V) and above (Ti6Al4V) the beta-phase transformation temperature (T = 980 °C), to study the effect of microstructural changes on osseointegration. The alloys were implanted in the femurs of hind legs of Wistar rats for 15, 30, and 60 days. Histology of the femur sections obtained for the first 15 days showed inflammatory tissue surrounding the implants and tissue contraction, which prevented osseointegration in early stages.

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