Effort Foraging Task reveals positive correlation between individual differences in the cost of cognitive and physical effort in humans.

Effort-based decisions, in which people weigh potential future rewards against effort costs required to achieve those rewards involve both cognitive and physical effort, though the mechanistic relationship between them is not yet understood. Here, we use an individual differences approach to isolate and measure the computational processes underlying effort-based decisions and test the association between cognitive and physical domains. Patch foraging is an ecologically valid reward rate maximization problem with well-developed theoretical tools. We developed the Effort Foraging Task, which embedded cognitive or physical effort into patch foraging, to quantify the cost of both cognitive and physical effort indirectly, by their effects on foraging choices. Participants chose between harvesting a depleting patch, or traveling to a new patch that was costly in time and effort. Participants' exit thresholds (reflecting the reward they expected to receive by harvesting when they chose to travel to a new patch) were sensitive to cognitive and physical effort demands, allowing us to quantify the perceived effort cost in monetary terms. The indirect sequential choice style revealed effort-seeking behavior in a minority of participants (preferring high over low effort) that has apparently been missed by many previous approaches. Individual differences in cognitive and physical effort costs were positively correlated, suggesting that these are perceived and processed in common. We used canonical correlation analysis to probe the relationship of task measures to self-reported affect and motivation, and found correlations of cognitive effort with anxiety, cognitive function, behavioral activation, and self-efficacy, but no similar correlations with physical effort.

Optimal ALT threshold for the automated diagnosis of MASLD: A population-based study using iLFT.

INTRODUCTION AND OBJECTIVES: Early diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD), especially with advanced fibrosis, is crucial due to the increased risk of complications and mortality. Serum alanine aminotransferase (ALT) is commonly used; however, many patients have normal ranges (<55 U/L) who may remain undetected. We investigated the clinical implications of a lower ALT cut-off (>30 U/L) using intelligent liver function testing (iLFT) to identify MASLD patients with and without advanced fibrosis in primary care. MATERIALS AND METHODS: All patients entering the iLFT diagnostic pathway had liver aetiological screening investigations if ALT >30 U/L. In those with MASLD the proportions with and without advanced fibrosis at different ALT thresholds: 31-41 U/L, 42-54 U/L and ≥55 U/L were compared. RESULTS: 16,373 patients underwent iLFT between March 2016 to April 2022. 762 (5 %) patients had MASLD with abnormal fibrosis scores, while 908 (6 %) had MASLD with normal fibrosis scores. 428 (56 %) patients were assessed in liver clinics, where 169 (39 %) had evidence of fibrosis. Of these, 22 (13 %) had ALT 31-41 U/L, 31 (18 %) had ALT 42-54 U/L and 116 (69 %) had ALT ≥55 U/L. 145 (86 %) patients had advanced fibrosis or cirrhosis, where 20 (14 %) had ALT 31-41 U/L, 28 (19 %) had ALT 42-54 U/L and 97 (67 %) had ALT ≥55 U/L. CONCLUSIONS: 33 % of MASLD patients with advanced fibrosis or cirrhosis had ALT 31-54 U/L, who would have been missed using the conventional ALT range. This suggests that lowering the ALT cut-off improves diagnosis of MASLD with advanced fibrosis in primary care.

An HPLC-UV validated bioanalytical method for measurement of in vitro phase 1 kinetics of α-synuclein binding bifunctional compounds.

Aggregates of the protein α-synuclein are associated with pathophysiology of Parkinson's disease and are present in Lewy Bodies found in the brains of Parkinson's patients. We previously demonstrated that bifunctional compounds composed of caffeine linked via a six carbon chain to either 1-aminoindan (C8-6-I) or nicotine (C8-6-N) bind α-synuclein and protect yeast cells from α-synuclein mediated toxicity.A critical step in development of positron emission tomography (PET) probes for neurodegenerative diseases is evaluation of their metabolic stability. We determined that C8-6-I, and C8-6-N both undergo phase 1 P450 metabolism in mouse, rat, and human liver microsomes. We utilised this metabolic information to guide the design of fluorinated analogues for use as PET probes and determined that the fluorine in 19F-C8-6-I and 19F-C8-6-N is stable to P450 enzymes.We have developed and validated an analytical HPLC-UV method following FDA and EMA guidelines to measure in vitro phase 1 kinetics of these compounds and determine their Vmax, KM and CLint,u in mouse liver microsomes. We found that C8-6-I and 19F-C8-6-I have a two- to fourfold lower CLint,u than C8-6-N, and 19F-C8-6-N. Our approach shows a simple, specific, and effective system to design and develop compounds as PET probes.

Employing in vitro metabolism to guide design of F-labelled PET probes of novel α-synuclein binding bifunctional compounds.

A challenge in the development of novel 18F-labelled positron emission tomography (PET) imaging probes is identification of metabolically stable sites to incorporate the 18F radioisotope. Metabolic loss of 18F from PET probes in vivo can lead to misleading biodistribution data as displaced 18F can accumulate in various tissues.In this study we report on in vitro hepatic microsomal metabolism of novel caffeine containing bifunctional compounds (C8-6-I, C8-6-N, C8-6-C8) that can prevent in vitro aggregation of α-synuclein, which is associated with the pathophysiology of Parkinson's disease. The metabolic profile obtained guided us to synthesize stable isotope 19F-labelled analogues in which the fluorine was introduced at the metabolically stable N7 of the caffeine moiety.An in vitro hepatic microsomal metabolism study of the 19F-labelled analogues resulted in similar metabolites to the unlabelled compounds and demonstrated that the fluorine was metabolically stable, suggesting that these analogues are appropriate PET imaging probes. This straightforward in vitro strategy is valuable for avoiding costly stability failures when designing radiolabelled compounds for PET imaging.

Musculoskeletal and Cognitive Effects of a Movement Intervention During Prolonged Standing for Office Work.

OBJECTIVE: To investigate whether use of a movement intervention when undertaking prolonged standing affected discomfort and cognitive function. BACKGROUND: Alternate work positions to break up prolonged sitting for office workers are being trialed, such as standing. Prolonged standing has potential negative health implications, including low back and lower limb discomfort, and may influence cognitive function. Introducing movement during standing may provide a healthy and productive alternative work posture. METHOD: Twenty adult participants undertook a laboratory study of 2 hr of standing and standing with movement (using a footrest) while performing computer work. Changes in discomfort and cognitive function, with muscle fatigue, low back angle, pelvis movement, lower limb swelling, and mental state, were investigated. RESULTS: Discomfort increased significantly over time across all body regions. Ankle/foot differed between conditions (incident rate ratio [95% confidence interval]: 1.89 [1.10-3.23]), with higher discomfort during standing with movement. Creative problem-solving errors increased during standing with movement and decreased during standing (Time × Condition: ß = 0.64 [0.10-1.18]), with no other cognitive function measure differences. Mental state deteriorated over time for both conditions, greater during standing with movement (Time × Condition: ß = 2.44 [0.23-4.66]). No significant interaction effects were found for the other outcome variables. CONCLUSION: Standing with movement provided no advantage in discomfort or cognitive function. There were some negative effects for ankle/foot discomfort and creative problem solving. An alternate footrest design and protocol for use may yield more favorable results. APPLICATION: Based on the results from this study, footrest use to raise alternative foot for forced 5-min intervals would not be recommended to assist with managing discomfort while prolonged standing in workplaces.

A detailed description of the short-term musculoskeletal and cognitive effects of prolonged standing for office computer work.

Due to concerns about excessive sedentary exposure for office workers, alternate work positions such as standing are being trialled. However, prolonged standing may have health and productivity impacts, which this study assessed. Twenty adult participants undertook two hours of laboratory-based standing computer work to investigate changes in discomfort and cognitive function, along with muscle fatigue, movement, lower limb swelling and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.47[1.36-1.59]). Sustained attention reaction time (ß = 18.25[8.00-28.51]) deteriorated, while creative problem solving improved (ß = 0.89[0.29-1.49]). There was no change in erector spinae, rectus femoris, biceps femoris or tibialis anterior muscle fatigue; low back angle changed towards less  lordosis, pelvis movement increased, lower limb swelling increased and mental state decreased. Body discomfort was positively correlated with mental state. The observed changes suggest replacing office work sitting with standing should be done with caution. Practitioner Summary: Standing is being used to replace sitting by office workers; however, there are health risks associated with prolonged standing. In a laboratory study involving 2 h prolonged standing discomfort increased (all body areas), reaction time and mental state deteriorated while creative problem-solving improved. Prolonged standing should be undertaken with caution.

Behavior of α-synuclein-drug complexes during nanopore analysis with a superimposed AC field.

Seven α-synuclein-drug complexes have been studied by nanopore analysis in which an AC field of 200 mV from 10 MHz to 1 GHz has been superimposed on the standard electrophoretic DC voltage of 100 mV. α-Synuclein has a large dipole moment and in the absence of drug the AC field causes the molecule to oscillate at the entrance to the pore and reduces its ability to translocate through the pore. Thus more bumping events are observed in the current blockade histograms. The binding of drugs to α-synuclein has a large effect on the event profiles depending on the region of α-synuclein to which the drugs bind. Caffeine and (-)-nicotine bind both the N- and C-termini causing the protein to adopt a loop conformation that allows translocation even in the AC field. Metformin, which binds only to the C-terminus also facilitates translocation. For these drugs there is good evidence that the AC field is causing the complex to dissociate as it enters the pore that has not been observed previously. In contrast, complexes with (+)-amphetamine that has an N-terminal binding site and cocaine that binds to the central region of the protein, show only small changes in the event profiles in an AC field.

A distinct triplex DNA unwinding activity of ChlR1 helicase.

Mutations in the human ChlR1 (DDX11) gene are associated with a unique genetic disorder known as Warsaw breakage syndrome characterized by cellular defects in genome maintenance. The DNA triplex helix structures that form by Hoogsteen or reverse Hoogsteen hydrogen bonding are examples of alternate DNA structures that can be a source of genomic instability. In this study, we have examined the ability of human ChlR1 helicase to destabilize DNA triplexes. Biochemical studies demonstrated that ChlR1 efficiently melted both intermolecular and intramolecular DNA triplex substrates in an ATP-dependent manner. Compared with other substrates such as replication fork and G-quadruplex DNA, triplex DNA was a preferred substrate for ChlR1. Also, compared with FANCJ, a helicase of the same family, the triplex resolving activity of ChlR1 is unique. On the other hand, the mutant protein from a Warsaw breakage syndrome patient failed to unwind these triplexes. A previously characterized triplex DNA-specific antibody (Jel 466) bound triplex DNA structures and inhibited ChlR1 unwinding activity. Moreover, cellular assays demonstrated that there were increased triplex DNA content and double-stranded breaks in ChlR1-depleted cells, but not in FANCJ(-/-) cells, when cells were treated with a triplex stabilizing compound benzoquinoquinoxaline, suggesting that ChlR1 melting of triple-helix structures is distinctive and physiologically important to defend genome integrity. On the basis of our results, we conclude that the abundance of ChlR1 known to exist in vivo is likely to be a strong deterrent to the stability of triplexes that can potentially form in the human genome.

Superposition of an AC field improves the discrimination between peptides in nanopore analysis.

In standard nanopore analysis a constant DC voltage is used to electrophoretically drive small molecules and peptides towards a pore. Superposition of an AC voltage at particular frequencies causes molecules to oscillate as they approach the pore which can alter the event parameters, the blockade current (I) and blockade time (T). Four peptides with similar structures were studied. Alpha-helical peptides A10 (FmocDDA10KK), A14, A18 and retro-inverso A10. It was shown that the ratio of translocations to bumping events could be manipulated by a combination of AC voltages and frequencies. In particular, A10 could be studied without interference from retro-inverso A10. Similarly, a large, intrinsically disordered protein of 140 amino acids, α-synuclein, which translocates the pore readily in a DC field could be prevented from doing so by application of an AC field of 200 mV at 100 MHz.

The relaxin receptor (RXFP1) utilizes hydrophobic moieties on a signaling surface of its N-terminal low density lipoprotein class A module to mediate receptor activation.

The peptide hormone relaxin is showing potential as a treatment for acute heart failure. Although it is known that relaxin mediates its actions through the G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), little is known about the molecular mechanisms by which relaxin binding results in receptor activation. Previous studies have highlighted that the unique N-terminal low density lipoprotein class A (LDLa) module of RXFP1 is essential for receptor activation, and it has been hypothesized that this module is the true "ligand" of the receptor that directs the conformational changes necessary for G protein coupling. In this study, we confirmed that an RXFP1 receptor lacking the LDLa module binds ligand normally but cannot signal through any characterized G protein-coupled receptor signaling pathway. Furthermore, we comprehensively examined the contributions of amino acids in the LDLa module to RXFP1 activity using both gain-of-function and loss-of-function mutational analysis together with NMR structural analysis of recombinant LDLa modules. Gain-of-function studies with an inactive RXFP1 chimera containing the LDLa module of the human LDL receptor (LB2) demonstrated two key N-terminal regions of the module that were able to rescue receptor signaling. Loss-of-function mutations of residues in these regions demonstrated that Leu-7, Tyr-9, and Lys-17 all contributed to the ability of the LDLa module to drive receptor activation, and judicious amino acid substitutions suggested this involves hydrophobic interactions. Our results demonstrate that these key residues contribute to interactions driving the active receptor conformation, providing further evidence of a unique mode of G protein-coupled receptor activation.

Insufficient Representation of Patients With Obesity in Randomized Controlled Trials Evaluating the Efficacy and Safety of Antimicrobials for Treatment of Skin and Skin Structure Infections: A Scoping Review.

Persons with obesity (PwO) represent approximately 50% of acute bacterial skin and skin structure infections (ABSSSIs) in the United States (US). There are currently insufficient data in PwO for drugs used for ABSSSIs. We conducted a scoping review of randomized controlled trials (RCTs) published between 2000 and 2022 to describe how frequently body size measures were reported. Weight and/or body mass index (BMI) were recorded in approximately 50% of the 69 RCTs. The average weights or BMIs were lower than US averages for most RCTs reporting data. None evaluated the impact of body size on outcomes in the original publication. Only 30% of newly approved drugs mention PwO representation in the prescribing information. More representative recruitment of PwO into RCTs is needed to help clinicians evaluate efficacy in these patients. We suggest that the Food and Drug Administration require companies to submit plans to ensure adequate PwO inclusion and that authors of RCTs report subgroup results based on body size.

Stability, toxicity and biological activity of retro, inversed and retro-inversed glucagon isomers.

Peptide modifications that improve pharmacological properties are of considerable therapeutic importance. Here we consider the retro (R), inversed (D) and retro-inversed (RI) isomers of glucagon with respect to structure, stability, toxicity and biological activity. Biologically, RI-glucagon demonstrated comparable in vivo activity as L-glucagon with respect to magnitude and duration of blood sugar elevation following i.p. administration to mice. Structurally, the isomers were investigated through circular dichroism (CD) and nanopore analysis. CD demonstrated a conserved potential for formation of secondary structure, which was independent of the direction of the peptide (L vs R; D vs RI) as well as formation of symmetry-related structures for the chiral isomers (L vs D; R vs RI). CD, therefore, discriminated chiral but not directional isomers. Nanopore analysis, which depends on interaction of the peptides with chiral pores, discriminated all four isomers on the basis of unique signatures of bumping and translocation. Nanopore analysis offered greater opportunity than CD to discriminate the isomers although neither technique provided a definitive biomarker of biological activity. Functionally, the R and RI isomers resist proteolytic degradation and none of the isomers possess hemolytic activity or cellular toxicity. Collectively, this investigation highlights the potentials and limitations of CD and nanopore analysis for investigation of peptide isomers as well as offering insight into the structural criteria to mimic peptide biological activity. For this example, retro-inversion, through undefined contributions of increased stability and maintained biological activity, was best suited to mimic the biological activity of the parent peptide.

Analysis of Rail Passenger Flow in a Rail Station Concourse Prior to and During the COVID-19 Pandemic Using Event-Based Simulation Models and Scenarios.

During COVID-19, certain means were proposed to improve crowd management in the Birmingham New Street railway station. To validate the current system of crowd management in the station, this paper examines the rail passenger flow in the concourse of the Birmingham New Street railway station and the passenger interactions and queueing phenomena associated with it, mainly at the ticket machines, offices and gates, prior to and during the implementation of COVID-19 measures. The passenger behaviour in the concourse of the station was simulated using the SIMUL8 event-based simulation modelling package. Three different scenarios were modelled to analyse the changes and impacts from pre-COVID-19 and within the COVID-19 context. The results revealed that passenger behaviour in railway stations is changing due to COVID-19. Specifically, passengers are more likely to buy tickets using their smartphones or online prior to or whilst entering the station so that they can go through the station concourse with minimal queuing times and avoid contact with a facility of common use at the station, whereas those without tickets are more likely to be in a queue to buy their tickets in the station. For pre-COVID, the results showed that even with a reduced number of ticket machines, overcrowding inside the station was unlikely to occur, as 80% of all passengers in the simulation completed service within a 15-minute time frame. However, during implementation of COVID-19 measures, as the number of passengers using the station dropped significantly and more passengers bought their tickets using their smartphones and/or online, queueing times were also shorter, and thus passengers spent less time in the system. The simulation results were in accordance with the expected practice; hence the effectiveness of the simulation model was verified. Overall, as a result of this study, the following suggestions to improve crowd management in a railway passenger station concourse are proposed: encourage passengers to purchase tickets on their smartphones, remove ticket gates and replace them with sensors, and provide a one-way passenger flow system in the main concourse of the station.

Adenosine A1 receptor ligands bind to α-synuclein: implications for α-synuclein misfolding and α-synucleinopathy in Parkinson's disease.

BACKGROUND: Accumulating α-synuclein (α-syn) aggregates in neurons and glial cells are the staples of many synucleinopathy disorders, such as Parkinson's disease (PD). Since brain adenosine becomes greatly elevated in ageing brains and chronic adenosine A1 receptor (A1R) stimulation leads to neurodegeneration, we determined whether adenosine or A1R receptor ligands mimic the action of known compounds that promote α-syn aggregation (e.g., the amphetamine analogue 2-aminoindan) or inhibit α-syn aggregation (e.g., Rasagiline metabolite 1-aminoindan). In the present study, we determined whether adenosine, A1R receptor agonist N6-Cyclopentyladenosine (CPA) and antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) could directly interact with α-syn to modulate α-syn aggregation and neurodegeneration of dopaminergic neurons in the substantia nigra (SN). METHODS: Nanopore analysis and molecular docking were used to test the binding properties of CPA and DPCPX with α-syn in vitro. Sprague-Dawley rats were administered with 7-day intraperitoneal injections of the A1R ligands and 1- and 2-aminoindan, and levels of α-syn aggregation and neurodegeneration were examined in the SN pars compacta and hippocampal regions using confocal imaging and Western blotting. RESULTS: Using nanopore analysis, we showed that the A1R agonists (CPA and adenosine) interacted with the N-terminus of α-syn, similar to 2-aminoindan, which is expected to promote a "knot" conformation and α-syn misfolding. In contrast, the A1R antagonist DPCPX interacted with the N- and C-termini of α-syn, similar to 1-aminoindan, which is expected to promote a "loop" conformation that prevents α-syn misfolding. Molecular docking studies revealed that adenosine, CPA and 2-aminoindan interacted with the hydrophobic core of α-syn N-terminus, whereas DPCPX and 1-aminoindan showed direct binding to the N- and C-terminal hydrophobic pockets. Confocal imaging and Western blot analyses revealed that chronic treatments with CPA alone or in combination with 2-aminoindan increased α-syn expression/aggregation and neurodegeneration in both SN pars compacta and hippocampus. In contrast, DPCPX and 1-aminoindan attenuated the CPA-induced α-syn expression/aggregation and neurodegeneration in SN and hippocampus. CONCLUSIONS: The results indicate that A1R agonists and drugs promoting a "knot" conformation of α-syn can cause α-synucleinopathy and increase neuronal degeneration, whereas A1R antagonists and drugs promoting a "loop" conformation of α-syn can be harnessed for possible neuroprotective therapies to decrease α-synucleinopathy in PD.

Management of Sarcopenia: A Network Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: This study aimed to determine the comparative effectiveness of interventions in treatment of sarcopenia. The primary outcome was the measure of treatment effect on muscle mass, and secondary outcomes were the treatment effect on muscle strength and physical performance. DESIGN: Systematic review and network meta-analysis (NMA). SETTING AND PARTICIPANTS: Participants with sarcopenia receiving interventions targeting sarcopenia in any setting. METHODS: Data sources: Relevant RCTs were identified by a systematic search of several electronic databases, including CINAHL, Embase, MEDLINE, and the Cochrane Central Registry of Controlled Trials (CENTRAL) from January 1995 to July 2019. Duplicate title and abstract and full-text screening, data extraction, and risk of bias assessment were performed. DATA EXTRACTION: All RCTs examining sarcopenia interventions [mixed exercise (combined aerobic and resistance exercise), aerobic exercise, resistance exercise, balance exercise, physical activity and protein or nutrition supplementation, acupuncture, whole-body vibration, protein supplement or interventions to increase protein intake, any nutritional intervention other than protein, and pharmacotherapy] were included. Comparators were standard care, placebo, or another intervention. DATA SYNTHESIS: We performed Bayesian NMA; continuous outcome data were pooled using the standardized mean difference effect size. Interventions were ranked using the surface under the cumulative ranking curve (SUCRA) for each outcome. RESULTS: A total of 59 RCTs were included after screening of 4315 citations and 313 full-text articles. Network meta-analysis of muscle mass outcome (including 46 RCTs, 3649 participants, 11 interventions) suggested that mixed exercise were the most effective intervention (SUCRA = 93.94%) to increase muscle mass. Physical activity and protein or nutrition supplementation, and aerobic exercise were the most effective interventions to improve muscle strength and physical performance, respectively. Overall, mixed exercise is the most effective intervention in increasing muscle mass and was one of the 3 most effective interventions in increasing muscle strength and physical performance. CONCLUSIONS AND IMPLICATIONS: Mixed exercise and physical activity with nutritional supplementation are the most effective sarcopenia interventions. Most of the included studies have a high risk of bias. More robust RCTs are needed to increase the confidence of our NMA results and the quality of evidence.

Kidney failure, CKD progression and mortality after nephrectomy.

PURPOSE: This study tested the hypothesis that progression of chronic kidney disease (CKD) is less aggressive in patients whose primary cause of CKD was nephrectomy, compared with non-surgical causes. METHODS: A sample of 5983 patients from five specialist nephrology practices was ascertained from the Queensland CKD Registry. Rates of kidney failure/death were compared on primary aetiology of CKD using multivariable Cox proportional hazards models. CKD progression was compared using multivariable linear and logistic regression analyses. RESULTS: Of 235 patients with an acquired single kidney as their primary cause of CKD, 24 (10%) and 38 (17%) developed kidney failure or died at median [IQR] follow-up times of 12.9 [2.5-31.0] and 33.6 [18.0-57.9] months after recruitment. Among patients with an eGFR < 45 mL/min per 1.73m2 at recruitment, patients with diabetic nephropathy and PCKD had the highest rates (per 1000 person-years) of kidney failure (107.8, 95% CI 71.0-163.8; 75.5, 95% CI 65.6-87.1); whereas, patients with glomerulonephritis and an acquired single kidney had lower rates (52.9, 95% CI 38.8-72.1; 34.6, 95% CI 20.5-58.4, respectively). Among patients with an eGFR ≥ 45 mL/min per 1.73m2, those with diabetic nephropathy had the highest rates of kidney failure (16.6, 95% CI 92.5-117.3); whereas, those with glomerulonephritis, PCKD and acquired single kidney had a lower risk (11.3, 95% CI 7.1-17.9; 11.7, 95% CI 3.8-36.2; 10.7, 95% CI 4.0-28.4, respectively). CONCLUSION: Patients who developed CKD after nephrectomy had similar rates of adverse events to most other causes of CKD, except for diabetic nephropathy which was consistently associated with worse outcomes. While CKD after nephrectomy is not the most aggressive cause of kidney disease, it is by no means benign, and is associated with a tangible risk of kidney failure and death, which is comparable to other major causes of CKD.

Effect of charge, topology and orientation of the electric field on the interaction of peptides with the α-hemolysin pore.

Nanopore analysis is an emerging technique of structural biology which employs nanopores, such as the α-hemolysin pore, as a biosensor. A voltage applied across a membrane containing a nanopore generates a current, which is partially blocked when a molecule interacts with the pore. The magnitude (I) and the duration (T) of the current blockade provide an event signature for that molecule. Two peptides, CY12(+)T1 and CY12(-)T1 with net charges + 2 and - 2, respectively, were analysed using different applied voltages and all four possible orientations of the electrodes and pore. The four orientations were vestibule downstream (VD), vestibule upstream (VU), stem downstream (SD) and stem upstream (SU) where vestibule and stem refer to the side of the pore on which the peptide was placed and downstream and upstream refer to the application of a positive or negative electrophoretic force, respectively. For CY12(+)T1, the effect of voltage on the event duration was consistent with translocation in the VD and SD configurations, but only intercalation events were observed in the VU and SU configurations. For CY12(-)T1, translocations were only observed in the VD and VU configurations. The results are interpreted in terms of two energy barriers on either side of the lumen of the pore. The difference in height of the barriers determines the preferred direction of exit. Electroosmotic flow and current rectification due to the pore as well as the dipole moment and charge of the peptide also play significant roles. Thus, factors other than simple electrophoresis are important for determining the interaction of small peptides with the pore.

The "Self" under COVID-19: Social role disruptions, self-authenticity and present-focused coping.

Social role disruption is a state involving upheaval of social identities, routines and responsibilities. Such disruption is presently occurring at a global scale due to the COVID-19 pandemic, which poses a threat not only to health and security but also to the social roles that underlie people's daily lives. Our collective response to combat the virus entails, for example, parents homeschooling children, friends socializing online, and employees working from home. While these collective efforts serve the greater good, people's social roles now lack continuity from what was authentic to the roles before the pandemic began. This, we argue, takes a psychological toll. Individuals feel inauthentic, or alienated and out-of-touch from their "true" selves, to the extent their social roles undergo change. As evidence, we report survey (Studies 1 & 4) and experimental (Studies 2 & 3) evidence that COVID-19-related role changes indeed increase inauthenticity. This effect occurs independent of (a) how positively/negatively people feel about COVID-19 (Study 2) and (b) how positively/negatively people feel about the role change itself (Studies 3 & 4). Moreover, we identify two moderators of this effect. First, this effect occurs when (and ostensibly because) the social roles undergoing change are central to an individual's sense of self (Study 2). Second, this effect depends on an individual's temporal perspective. People can safeguard their self-authenticity in the face of changing social roles if they stay focused on the here-and-now (the present and immediate future), rather than focusing on the past (pre-COVID-19) or future (post-COVID-19) (Studies 3 & 4). This advantage for present-focused coping is observed in both the U.S.A. (Study 3) and Hong Kong (Study 4). We suggest that the reason people feel more authentically themselves when they maintain a present focus is because doing so makes the discontinuity of their social roles less salient.

Methodological considerations for the measurement of arterial stiffness using applanation tonometry.

INTRODUCTION: Accurate comparisons of carotid--femoral pulse wave velocity (cfPWV) within and across studies require standardized procedures. Guidelines suggest reporting the average of at least two cfPWV measurements; if the difference exceeds 0.5 m/s, a third measurement should be taken, and the median reported. Another method involves repeating measurements until two values are within 0.5 m/s. However, in many studies, duplicate measurements are averaged irrespective of the difference between readings. We evaluated the impact of these methods on the reported cfPWV value. METHODS: Measurements of cfPWV (SphygmoCor) from five studies included individuals spanning a wide age range, with or without comorbid conditions, and pregnant women. In participants with at least three high-quality measurements, differences between the median value (MED) and the average of the first two cfPWV measurements (AVG1) and the average of two cfPWV measurements within 0.5 m/s (AVG2) were evaluated using paired t-tests and Bland--Altman plots. RESULTS: Participants' mean age was 50 ±â€Š14 years and BMI was 28.0 ±â€Š5.5 kg/m2 (N = 306, 79% women). The overall mean difference was -0.10 m/s (95% CI 0.17 to -0.04) between MED and AVG1, and 0.11 m/s (95% CI 0.05--0.17) between MED and AVG2. The absolute difference exceeded 0.5 m/s in 34% (MED-AVG1) and 22% (MED-AVG2) of participants, and 1 m/s in 8% of participants (both MED-AVG1 and MED-AVG2). Scatter around the bias line increased with higher mean cfPWV values. CONCLUSION: Although the overall mean difference in cfPWV between protocols was not clinically relevant, large variation led to absolute differences exceeding 0.5 m/s in a large proportion of participants.

Nanopore analysis of the interaction of metal ions with prion proteins and peptides.

Nanopore analysis can be used to study conformational changes in individual peptide or protein molecules. Under an applied voltage there is a change in the event parameters of blockade current or time when a molecule bumps into or translocates through the pore. If a molecule undergoes a conformational change upon binding a ligand or metal ion the event parameters will be altered. The objective of this research was to demonstrate that the conformation of the prion protein (PrP) and prion peptides can be modulated by binding divalent metal ions. Peptides from the octarepeat region (Octa2, (PHGGGWGQ)2 and Octa 4, (PHGGGWGQ)4), residues 106-126 (PrP106-126), and the full-length Bovine recombinant prion (BrecPrP) were studied with an alpha-hemolysin pore. Octa2 readily translocated the pore but significant bumping events occurred on addition of Cu(II) and to a lesser extent Zn(II), demonstrating that complex formation was occurring with concomitant conformational changes. The binding of Cu(II) to Octa4 was more pronounced and at high concentrations only a small proportion of the complex could translocate. Addition of Zn(II) also caused significant changes to the event parameters but Mg(II) and Mn(II) were inert. Addition of Cu(II) to PrP106-126 caused the formation of a very tight complex, which could not translocate the pore. Small changes were observed with Zn(II), but not with Mg(II) or Mn(II). Analysis of BrecPrP showed that about 37% were translocation events, but on addition of Cu(II) or Zn(II) these disappeared and only bumping events were recorded. Suprisingly, addition of Mn(II) caused an increase in translocation events to about 64%. Thus, conformational changes to prions upon binding metal ions are readily observed by nanopore analysis.