title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=640 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Rapid restructurization of conformationally-distinct alpha-synuclein amyloid fibrils at an elevated temperature link: https://peerj.com/articles/14137 last-modified: 2022-09-30 description: Protein aggregation in the form of amyloid fibrils is linked with the onset and progression of more than 30 amyloidoses, including multiple neurodegenerative disorders, such as Alzheimer’s or Parkinson’s disease. Despite countless studies and years of research, the process of such aggregate formation is still not fully understood. One peculiar aspect of amyloids is that they appear to be capable of undergoing structural rearrangements even after the fibrils have already formed. Such a phenomenon was reported to occur in the case of alpha-synuclein and amyloid beta aggregates after a long period of incubation. In this work, we examine whether incubation at an elevated temperature can induce the restructurization of four different conformation alpha-synuclein amyloid fibrils. We show that this structural alteration occurs in a relatively brief time period, when the aggregates are incubated at 60 °C. Additionally, it appears that during this process multiple conformationally-distinct alpha-synuclein fibrils all shift towards an identical secondary structure. creator: Mantas Ziaunys creator: Andrius Sakalauskas creator: Kamile Mikalauskaite creator: Vytautas Smirnovas uri: https://doi.org/10.7717/peerj.14137 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Ziaunys et al. title: Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations link: https://peerj.com/articles/14142 last-modified: 2022-09-30 description: BackgroundProgressive overload is a principle of resistance training exercise program design that typically relies on increasing load to increase neuromuscular demand to facilitate further adaptations. However, little attention has been given to another way of increasing demand—increasing the number of repetitions.ObjectiveThis study aimed to compare the effects of two resistance training programs: (1) increasing load while keeping repetition range constant vs (2) increasing repetitions while keeping load constant. We aimed to compare the effects of these programs on lower body muscle hypertrophy, muscle strength, and muscle endurance in resistance-trained individuals over an 8-week study period.MethodsForty-three participants with at least 1 year of consistent lower body resistance training experience were randomly assigned to one of two experimental, parallel groups: A group that aimed to increase load while keeping repetitions constant (LOAD: n = 22; 13 men, nine women) or a group that aimed to increase repetitions while keeping load constant (REPS: n = 21; 14 men, seven women). Subjects performed four sets of four lower body exercises (back squat, leg extension, straight-leg calf raise, and seated calf raise) twice per week. We assessed one repetition maximum (1RM) in the Smith machine squat, muscular endurance in the leg extension, countermovement jump height, and muscle thickness along the quadriceps and calf muscles. Between-group effects were estimated using analyses of covariance, adjusted for pre-intervention scores and sex.ResultsRectus femoris growth modestly favored REPS (adjusted effect estimate (CI90%), sum of sites: 2.8 mm [−0.5, 5.8]). Alternatively, dynamic strength increases slightly favored LOAD (2.0 kg [−2.4, 7.8]), with differences of questionable practical significance. No other notable between-group differences were found across outcomes (muscle thicknesses, <1 mm; endurance, <1%; countermovement jump, 0.1 cm; body fat, <1%; leg segmental lean mass, 0.1 kg), with narrow CIs for most outcomes.ConclusionBoth progressions of repetitions and load appear to be viable strategies for enhancing muscular adaptations over an 8-week training cycle, which provides trainers and trainees with another promising approach to programming resistance training. creator: Daniel Plotkin creator: Max Coleman creator: Derrick Van Every creator: Jaime Maldonado creator: Douglas Oberlin creator: Michael Israetel creator: Jared Feather creator: Andrew Alto creator: Andrew D. Vigotsky creator: Brad J. Schoenfeld uri: https://doi.org/10.7717/peerj.14142 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Plotkin et al. title: Exercise interventions in migraine patients: a YouTube content analysis study based on grades of recommendation link: https://peerj.com/articles/14150 last-modified: 2022-09-30 description: BackgroundMigraine is the second leading cause of disability worldwide, engendering a high economic cost in developed countries. The adverse events related to pharmacological treatment use have increased interest in non-pharmacological interventions such as exercise. YouTube offers a public source of information for migraine patients regarding exercise interventions for migraine improvement. However, this information has not been validated to ensure the quality and validity of its content.ObjectiveThis qualitative content analysis study aims to review and evaluate YouTube videos regarding exercise for migraine.MethodsA systematic review of the current evidence regarding exercise for migraine was performed to establish evidence classification and grades of recommendation with the Scottish Intercollegiate Guidelines Network tool. The data sources were PubMed, PEDro, Cochrane, EBSCO, Google Scholar and Web of Science. The quality of YouTube videos on exercise in migraine was reviewed using the Global Quality Scale and DISCERN scale. Finally, the classification in grades of recommendation was used to evaluate the included videos in terms of the various exercise modalities.ResultsThe classification into recommendation grades showed a grade B for aerobic exercise, yoga and changes in lifestyle behavior regarding exercise. A total of 129 videos were included. The healthcare and exercise professional authors produced higher quality videos with a significant statistical difference, although the alternative therapists and patients’ videos had a greater impact and a higher viewership based on correlation analysis. The evaluation of the videos based on the recommendation grades could only include 90 videos. 71% of these videos showed a B grade of recommendation, which corresponded to fewer than half of the total included videos.ConclusionsYouTube needs higher quality videos on exercise for migraine, and healthcare and exercise professional authors need to improve their scoping strategies to acquire more views. The authors of YouTube videos should have better access to the best current evidence regarding exercise interventions in migraine. creator: Álvaro Reina-Varona creator: Borja Rodríguez de Rivera-Romero creator: Carlos Donato Cabrera-López creator: José Fierro-Marrero creator: Irene Sánchez-Ruiz creator: Roy La Touche uri: https://doi.org/10.7717/peerj.14150 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Reina-Varona et al. title: Optimal selection of COVID-19 vaccination sites in the Philippines at the municipal level link: https://peerj.com/articles/14151 last-modified: 2022-09-30 description: In this work, we present an approach to determine the optimal location of coronavirus disease 2019 (COVID-19) vaccination sites at the municipal level. We assume that each municipality is subdivided into smaller administrative units, which we refer to as barangays. The proposed method solves a minimization problem arising from a facility location problem, which is formulated based on the proximity of the vaccination sites to the barangays, the number of COVID-19 cases, and the population densities of the barangays. These objectives are formulated as a single optimization problem. As an alternative decision support tool, we develop a bi-objective optimization problem that considers distance and population coverage. Lastly, we propose a dynamic optimization approach that recalculates the optimal vaccination sites to account for the changes in the population of the barangays that have completed their vaccination program. A numerical scheme that solves the optimization problems is presented and the detailed description of the algorithms, which are coded in Python and MATLAB, are uploaded to a public repository. As an illustration, we apply our method to determine the optimal location of vaccination sites in San Juan, a municipality in the province of Batangas, in the Philippines. We hope that this study may guide the local government units in coming up with strategic and accessible plans for vaccine administration. creator: Kurt Izak Cabanilla creator: Erika Antonette T. Enriquez creator: Arrianne Crystal Velasco creator: Victoria May P. Mendoza creator: Renier Mendoza uri: https://doi.org/10.7717/peerj.14151 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Cabanilla et al. title: Mode-specific effects of concentric and eccentric isokinetic training of the hamstring muscle at slow angular velocity on the functional hamstrings-to-quadriceps ratio-a randomized trial link: https://peerj.com/articles/13842 last-modified: 2022-09-29 description: BackgroundPrevious studies have examined the mode specificity of eccentric and concentric isokinetic training, but have reported conflicting results. Few studies have reported that eccentric and concentric isokinetic training are mode-specific, i.e., they will increase only the eccentric or concentric strength, respectively. Other studies have reported that mode specificity does not exist. Therefore, this study aimed to assess the mode-specific effects of eccentric and concentric isokinetic training of the hamstring muscle at slow angular velocity on eccentric peak torque of the hamstring (PTecc), concentric peak torque of the quadriceps (PTcon), acceleration time of the hamstring (AThams) and quadriceps (ATquad), deceleration time of the hamstring (DThams) and quadriceps (DTquad), time to peak torque of the hamstring (TPThams) and quadriceps (TPTquad), and functional Hamstring-to-Quadriceps ratio (PTecc/PTcon).SubjectsA total of 30 participants were randomly divided into eccentric and concentric groups.MethodsTwo groups pre-test-post-test experimental design was used. In the eccentric and concentric groups, eccentric and concentric isokinetic training of hamstring muscle was performed respectively, at an angular velocity of 60°/s for 6 weeks duration. PTecc, PTcon, AThams, ATquad, DThams, DTquad, TPThams, TPTquad, and PTecc/PTcon were measured before and after the completion of training.ResultsIn the eccentric group, a significant difference (p < 0.05) was observed in PTecc (increased by 21.55%), AThams (decreased by 42.33%), ATquad (decreased by 28.74%), and PTecc/PTcon (increased by 17.59%). No significant difference (p > 0.05) was observed in PTcon, TPThams, TPTquad, DThams, and DTquad. In the concentric group, a significant difference (p < 0.05) was observed in PTecc (increased by 12.95%), AThams (decreased by 27.38%) ATquad (decreased by 22.08%), DTquad (decreased by 26.86%), and PTecc/PTcon (increased by 8.35%). No significant difference (p > 0.05) was observed in PTquad, TPThams, TPTquad, and DThams. Between-group analysis revealed a significant difference (p < 0.05) only in TPTquad; otherwise, in the rest of the parameters, no significant difference (p > 0.05) was observed.ConclusionsBoth eccentric and concentric isokinetic training of the hamstring for 6 weeks increased PTecc, PTecc/PTcon, and decreased AThams and ATquad. The effects of eccentric and concentric isokinetic training of the hamstring on PTecc, PTecc/PTcon, AThams, and ATquad were not mode specific. creator: Kushla Nand Sharma creator: Nishat Quddus creator: Unaise Abdul Hameed creator: Sohrab Ahmad Khan creator: Anita Kumari creator: Ahmad H. Alghadir creator: Masood Khan uri: https://doi.org/10.7717/peerj.13842 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Sharma et al. title: The preclinical pharmacological study of a novel intravenous anesthetic, ET-26 hydrochloride, in aged rats link: https://peerj.com/articles/13995 last-modified: 2022-09-29 description: BackgroundET-26 hydrochloride (ET-26HCl) is a novel analogue of etomidate approved for clinical trials. However, all results from recent studies were accomplished in young adult animals. The objective of this study was to evaluate the efficacy and safety of ET-26HCl in aged rats.MethodsAged Sprague-Dawley rats were randomly divided into three groups (three males and three females in each group) were given dose of two-fold of median effective dose (ED50) of ET-26HCl, etomidate and propofol: the measurements of loss of the righting reflex (LORR) and cardiovascular and respiratory function after injection at the two-fold dose of the median effective dose were used for evaluation of effectiveness and safety, and the modified adrenocorticotropic hormone-stimulation experiment was used to evaluate the inhibition effect of the drugs on the synthesis of adrenal cortical hormones.ResultsThere was no significant difference in the onset time among propofol, etomidate and ET-26HCl. The duration of propofol (850.5 ± 77.4 s) was significantly longer than that caused by etomidate (489.8 ± 77.0 s, p = 0.007) and ET-26HCl (347.3 ± 49.0 s, p = 0.0004). No significant difference was observed in the time to stand and normal activity among drugs. A total of 66.7% of rats in the ET-26HCl group were evaluated to have mild hematuria. Then, etomidate and ET-26HCl had a milder blood pressure inhibition effect than propofol. Apnea was observed in all rats administered propofol and the duration for this side effect was 45.0 ± 9.0 s. For etomidate and ET-26HCl, no apnea was observed. No other clinical signs of side-effect were observed, and no rats died. No significant difference was observed in corticosterone concentrations between ET-26HCl and solvent group. However, rats administered etomidate had lower corticosterone concentrations than those administered ET-26HCl at 15, 30, and 60 min.ConclusionsOur results indicate ET-26HCl in aged rats is an effective sedative-hypnotic with stable myocardial and respiratory performance and also have mild adrenocortical suppression. Thus, these findings increase the potential for the clinical use of ET-26HCl in the elderly population. creator: Pan Chang creator: YongWei Su creator: DeYing Gong creator: Yi Kang creator: Jin Liu creator: YuJun Zhang creator: Wen-sheng Zhang uri: https://doi.org/10.7717/peerj.13995 license: https://creativecommons.org/licenses/by-nc/4.0 rights: ©2022 Chang et al. title: Analysis of genetic diversity among Chinese Cyclocybe chaxingu strains using ISSR and SRAP markers link: https://peerj.com/articles/14037 last-modified: 2022-09-29 description: BackgroundCyclocybe chaxingu is an edible and medicinal fungal species commonly cultivated in China. The major problems currently facing by growers of C. chaxingu is the random labeling of strains and strains aging and degeneration. Therefore, an evaluation of genetic diversity is essential for the conservation and reproducing programs of this species.MethodsIn the present study, 24 widely cultivated strains were collected from the main producing areas of China, and the genetic diversity analysis was performed. DNA polymorphism among these Chinese C. chaxingu strains was analyzed using inter-simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) markers.ResultsEight ISSR primers amplified a total of 75 DNA fragments of which 61 (81.33%) were polymorphic. Fifteen SRAP primer combinations amplified 166 fragments of which 132 (79.52%) were polymorphic. Cluster analysis showed that the C. chaxnigu strains fall into five groups with a genetic distance values ranging from 0.06 to 0.60 by ISSR analysis, while the SRAP analysis divided the test strains into four groups within the range of genetic distance from 0.03 to 0.57. The results of the present study reveal a high level of genetic diversity among the widely cultivated C. chaxingu strains. creator: Jin-Hao Liu creator: Fang-Hui Ding creator: Hai-Yan Song creator: Ming-Hui Chen creator: Dian-Ming Hu uri: https://doi.org/10.7717/peerj.14037 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Liu et al. title: Macrophages play a key role in tissue repair and regeneration link: https://peerj.com/articles/14053 last-modified: 2022-09-29 description: Tissue regeneration after body injury has always been a complex problem to resolve for mammals. In adult mammals, the repair process after tissue injury is often accompanied by continuous and extensive fibrosis, which leads to scars. This process has been shown to severely hinder regeneration. Macrophages, as widely distributed innate immune cells, not only play an important role in various pathological processes, but also participate in the repair process before tissue regeneration and coordinate the regeneration process after repair. This review will discuss the various forms and indispensability of macrophages involved in repair and regeneration, and how macrophages play a role in the repair and regeneration of different tissues. creator: Yajie Yu creator: Zhongyu Yue creator: Mengli Xu creator: Meiling Zhang creator: Xue Shen creator: Zihan Ma creator: Juan Li creator: Xin Xie uri: https://doi.org/10.7717/peerj.14053 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Yu et al. title: The validity and reliability of the Test of Memory Strategies among Italian healthy adults link: https://peerj.com/articles/14059 last-modified: 2022-09-29 description: BackgroundPrevious literature has shown that executive functions (EF) are related to performance in memory (M) tasks. Nevertheless, there is a shortage of psychometric tests that examine these two constructs simultaneously. The Test of Memory Strategies (TMS; previously validated in Spain and Portugal) could be a useful verbal learning task that evaluates these two constructs at once. In this study, we aimed to evaluate the psychometric properties of the TMS in an Italian adult sample.MethodOne hundred twenty-one healthy volunteers (74 F, Mean age = 45.9 years old, SD = 20.4) who underwent a neuropsychological examination participated in this study. We conducted a Confirmatory factor analysis (CFA) to evaluate the structural validity of the TMS. We conducted a latent variable analysis to examine convergent and discriminant validity of the TMS sub-scale scores reflecting executive functions and memory. We also examined the TMS reliability in terms of internal consistency through the McDonald’s omega.ResultsThe CFA confirmed the expectation that the TMS-1 and TMS-2 subtests reflect a factor and that the TMS-3, TMS-4, and TMS-5 subtests reflect a different factor. This result is in line with the prediction that TMS-1 and TMS-2 require the use of executive functions and memory simultaneously, and therefore we called this factor executive functions (EF); whereas the TMS-3, TMS-4, and TMS-5 subtests require less involvement of executive functions, thus reflecting a construct that we named memory (M). The TMS subtests for EF and M showed convergent validity with the test scores using a traditional neuropsychological battery, assessing memory and executive functions separately. Finally, the reliability of the subtests was good.ConclusionsThese preliminary findings suggest that TMS is a valid and reliable scale to simultaneously assess M and EF while among Italian healthy adults. creator: Maria Grazia Vaccaro creator: Marco Tullio Liuzza creator: Massimiliano Pastore creator: Nuria Paúl creator: Raquel Yubero creator: Andrea Quattrone creator: Gabriella Antonucci creator: Antonio Gambardella creator: Fernando Maestú uri: https://doi.org/10.7717/peerj.14059 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Vaccaro et al. title: A spectacular new species of Hyloscirtus (Anura: Hylidae) from the Cordillera de Los Llanganates in the eastern Andes of Ecuador link: https://peerj.com/articles/14066 last-modified: 2022-09-29 description: We have discovered a spectacular new species of frog in the genus Hyloscirtus, belonging to the H. larinopygion species group. The adult female is characterized by a mostly black body with large bright red spots on the dorsal and ventral surface, extremities, and toe pads. The adult male is unknown. Small juveniles are characterized by a yellow body with variable black markings on the flanks; while one larger juvenile displayed irregular orange or yellow marks on a black background color, with light orange or yellow toe pads. Additional distinctive external morphological features such as cloacal ornamentation are described, and some osteological details are imaged and analyzed. The performed phylogeny places the new species as the sister to a clade consisting of ten taxa, all of which are part of the H. larinopygion group. We use genetic distances to fit the new species into a published time-calibrated phylogeny of this group; our analysis based on the published chronology suggests that the divergence of the new species from its known congeners pre-dates the Quaternary period. The new species is currently only known only from Cerro Mayordomo, in Fundación EcoMinga´s Machay Reserve, at 2,900 m in the eastern Andes of Tungurahua province, Ecuador, near the southern edge of Los Llanganates National Park, but its real distribution may be larger. creator: Juan P. Reyes-Puig creator: Darwin Recalde creator: Fausto Recalde creator: Claudia Koch creator: Juan M. Guayasamin creator: Diego F. Cisneros-Heredia creator: Lou Jost creator: Mario H. Yánez-Muñoz uri: https://doi.org/10.7717/peerj.14066 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Reyes-Puig et al.