Effects of age and size in the ears of gekkonomorph lizards: middle-ear morphology with evolutionary implications

The function of the ear depends in part on its absolute size and internal proportions. Thus, in both young individuals and small species, the middle ear is expected to be allometrically enlarged despite its smaller absolute size. Here we aim to compare the ontogenetic allometry of relevant middle-ear structures as observed within gecko (gekkonomorph lizards) species, with the evolutionary allometry observed interspecifically. These observations also provide middle-ear data for future evaluation of variation in auditory sensitivity. The material comprised 84 museum specimens of geckos, representing nine species of three gekkonomorph subfamilies. The results of dissections and measurements show that different reports notwithstanding, the middle-ear ossicular chain is indeed structured as described for geckos by Werner and Wever. Some sexual dimorphism is indicated, but this requires further study. During postnatal ontogeny, the allometric growth in the ratio of the columellar footplate area to body length differed between the intraspecific and interspecific levels, hence species differences in the middle ear do not merely result from animal size. The ratio of the tympanic membrane area to the columellar footplate area increased during ontogeny. In this, geckos resemble birds and probably also mammals. Similarly, when the comparison was among adults representing different species, the ratio of the tympanic membrane area to the columellar footplate area increased with body size. In this, however, the geckos differed from birds and mammals, in which this ratio varied taxonomically, irrespective of body size. It would thus seem that middle-ear proportions have evolved among geckos to produce small interspecific differences, but among amniote tetrapods they have evolved according to different principles in the classes reptiles, birds, and mammals.     

Iron, ferritin and proteins of the methionine-centered redox cycle in young and old rat hearts

Progressive oxidation of cellular components constitutes a major mechanism of the aging process. An emerging paradigm of redox signaling suggests that low level oxidants activate protective pathways resulting in prolonged cell survival. This report centers on the study of cardiac muscle in young and old rats, including (i) the expression of ferritin (Ft) the major iron storage protein, and (ii) the expression of the major proteins of the methionine-centered redox cycle (MCRC), which controls the cellular methionine redox status. Total amounts of Ft (protein) and its mRNA encoding for Ft L-subunit (Ft-L) were higher in the aged hearts, indicating that the iron-binding capacity of myocardial Ft increased with age. Among the proteins of the MCRC, methionine sulfoxide reductases A and B (MsrA, MsrB) and MsrA mRNA were significantly higher in hearts of old rats with a significant decrease in MsrA activity. The observed up-regulation of the expression of Msr and Ft-L could represent a protective response to the increased oxidative stress in the aging myocardium.     

Circular Economy of Construction and Demolition Waste: A Literature Review on Lessons,Challenges, and Benefits

Conventionally, in a linear economy, C&D (Construction and Demolition) waste was considered as zero value materials, and, as a result of that, most C&D waste materials ended up in landfills. In recent years, with the increase in the awareness around sustainability and resource management, various countries have started to explore new models to minimize the use of limited resources which are currently overused, mismanaged, or quickly depleting. In this regard, the implementation of CE (Circular Economy) has emerged as a potential model to minimize the negative impact of C&D wastes on the environment. However, there are some challenges hindering a full transition to CE in the construction and demolition sectors. Therefore, this review paper aims to critically scrutinize different aspects of C&D waste and how CE can be integrated into construction projects. Reviewing of the literature revealed that the barriers in the implementation of CE in C&D waste sectors fall in five main domains, namely legal, technical, social, behavioral, and economic aspects. In this context, it was found that policy and governance, permits and specifications, technological limitation, quality and performance, knowledge and information, and, finally, the costs associated with the implementation of CE model at the early stage are the main barriers. In addition to these, from the contractors’ perspective, C&D waste dismantling, segregation, and on-site sorting, transportation, and local recovery processes are the main challenges at the start point for small-scale companies. To address the abovementioned challenges, and also to minimize the ambiguity of resulting outcomes by implementing CE in C&D waste sectors, there is an urgent need to introduce a global framework and a practicable pathway to allow companies to implement such models, regardless of their scale and location. Additionally, in this paper, recommendations on the direction for areas of future studies for a reduction in the environmental impacts have been provided. To structure an effective model approach, the future direction should be more focused on dismantling practices, hazardous material handling, quality control on waste acceptance, and material recovery processes, as well as a incentivization mechanism to promote ecological, economic, and social benefits of the CE for C&D sectors.     

The Dynamics of Periapical Lesions in Endodontically Treated Teeth That Are Left without Intervention: A Longitudinal Study

Introduction

The long-term dynamics of periapical lesions in endodontically treated teeth is not fully elucidated, thus presenting a clinical dilemma regarding the need for an intervention. The aim of the study was to retrospectively evaluate the long-term dynamics of periapical lesions that were left without intervention in endodontically treated teeth.

Methods

Periapical status surveys of patients treated in a public dental clinic were retrospectively evaluated for the presence of periapical lesions in endodontically treated coronally restored teeth. The dynamics of the included periapical lesions was evaluated based on the periapical index (PAI) score changes between 2 consecutive periapical surveys of at least a 4-year interval. The influence of various factors on lesion dynamics was statistically evaluated.

Results

The study cohort consisted of 74 patients with a total of 200 endodontically treated teeth having periapical lesions that fulfilled the inclusion criteria. Fifty-seven (28.5%) lesions remained unchanged, 103 (51.5%) lesions worsened (PAI score increased), and 40 (20%) lesions improved (PAI score decreased). Poor root canal filling and poor restoration were found to adversely affect the long-term dynamics of the periapical lesions (P < .05). Age, sex, and the presence of a post had no statistically significant influence on lesion dynamics (P > .05).

Conclusions

Poor root canal filling and poor restoration may adversely affect the long-term dynamics of periapical lesions that are left without intervention in endodontically treated teeth. Therefore, in cases of poor root canal filling or poor restoration, further intervention may be indicated.     

Effects of age and size in the ears of gekkotan lizards: auditory sensitivity, its determinants, and new insights into tetrapod middle-ear function

Do related, differently sized species differ in size-related structural or functional traits merely because they mature at different points of a uniform allometric ontogenetic growth curve, or do they evolutionarily diverge? We tested ears of gekkotan lizards through experiments distinguishing the two. Auditory sensitivity was assessed by compound action potential (CAP) thresholds in eight species. The best thresholds characterizing species ranged 22–72 dB sound pressure level at 0.5–1.0 kHz. Direct acoustic stimulation of the columella footplate elevated thresholds by 25–50 dB. Intraspecific CAP sensitivity was primarily affected by body length in Eublepharis macularius, but by tympanic-membrane velocity in Oedura marmorata. The chief factor determining middle-ear function (difference in CAP sensitivity before and after middle-ear ablation) was body length in both species. A secondary factor was the middle-ear hydraulic lever ratio in E. macularius, but the mechanical lever in O. marmorata. When intra- and interspecific data were compared, the relation of CAP thresholds to body size in E. macularius resembled the interspecific regression. The intraspecific regression of auditory sensitivity over tympanic membrane velocity in O. marmorata differed from that calculated interspecifically. Hence, the evolutionary contribution to size effects on CAP sensitivity exceeds the ontogenetic contribution. Putatively, body length affects CAP sensitivity through absolute sizes of tympanic membrane and columella footplate. These newly discovered effects join those of the hydraulic lever and (interspecifically) hair-cell number to improve the hearing of larger species that vocally communicate across wider spaces, apparently throughout the Tetrapoda.     

The clinical practice of risk reduction for Alzheimer's disease: A precision medicine approach

Like virtually all age-related chronic diseases, late-onset Alzheimer's disease (AD) develops over an extended preclinical period and is associated with modifiable lifestyle and environmental factors. We hypothesize that multimodal interventions that address many risk factors simultaneously and are individually tailored to patients may help reduce AD risk. We describe a novel clinical methodology used to evaluate and treat patients at two Alzheimer's Prevention Clinics. The framework applies evidence-based principles of clinical precision medicine to tailor individualized recommendations, follow patients longitudinally to continually refine the interventions, and evaluate N-of-1 effectiveness (trial registered at ClinicalTrials.gov NCT03687710). Prior preliminary results suggest that the clinical practice of AD risk reduction is feasible, with measurable improvements in cognition and biomarkers of AD risk. We propose using these early findings as a foundation to evaluate the comparative effectiveness of personalized risk management within an international network of clinician researchers in a cohort study possibly leading to a randomized controlled trial.