A mediational theory of equivalence relations and transformation of function.

In this article, we describe a mediational theory of emergent or derived relations resulting from matching-to-sample procedures that produce equivalence and transformation of function. According to a mediational theory, behaviors that occur at the time of reinforcement mediate subsequent behavioral relations referred to as "derived" or "emergent." Such relations have been documented for decades in studies using mostly matching-to-sample procedures with humans and nonhumans.

Do Invasive Jorō Spiders () from Asia Avoid Eating Unpalatable Monarch Butterflies () in North America?

An invasive spider from East Asia has established in the U.S. southeast (the "jorō spider," ) and is rapidly expanding its range.

Ionization detail parameters and cluster dose: a mathematical model for selection of nanodosimetric quantities for use in treatment planning in charged particle radiotherapy.

. To propose a mathematical model for applying ionization detail (ID), the detailed spatial distribution of ionization along a particle track, to proton and ion beam radiotherapy treatment planning (RTP)..

Galactic cosmic ray simulation at the NASA space radiation laboratory - Progress, challenges and recommendations on mixed-field effects.

For missions beyond low Earth orbit to the moon or Mars, space explorers will encounter a complex radiation field composed of various ion species with a broad range of energies. Such missions pose significant radiation protection challenges that need to be solved in order to minimize exposures and associated health risks. An innovative galactic cosmic ray simulator (GCRsim) was recently developed at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL).

Changing faces of mitochondrial disease: autosomal recessive disease mimicking myasthenia gravis and progressive supranuclear palsy.

Background: Mitochondrial disorders are known to cause diverse neurological phenotypes which cause a diagnostic challenge to most neurologists. Pathogenic polymerase gamma () variants have been described as a cause of chronic progressive external ophthalmoplegia, which manifests with ptosis, horizontal and vertical eye movement restriction and myopathy. Autosomal dominant progressive external ophthalmoplegia is rarely associated with Parkinsonism responsive to levodopa.

Genetic testing for mitochondrial disease: the United Kingdom best practice guidelines.

Primary mitochondrial disease describes a diverse group of neuro-metabolic disorders characterised by impaired oxidative phosphorylation. Diagnosis is challenging; >350 genes, both nuclear and mitochondrial DNA (mtDNA) encoded, are known to cause mitochondrial disease, leading to all possible inheritance patterns and further complicated by heteroplasmy of the multicopy mitochondrial genome. Technological advances, particularly next-generation sequencing, have driven a shift in diagnostic practice from 'biopsy first' to genome-wide analyses of blood and/or urine DNA.

Online charge measurement for petawatt laser-driven ion acceleration.

Laser-driven ion beams have gained considerable attention for their potential use in multidisciplinary research and technology. Preclinical studies into their radiobiological effectiveness have established the prospect of using laser-driven ion beams for radiotherapy. In particular, research into the beneficial effects of ultrahigh instantaneous dose rates is enabled by the high ion bunch charge and uniquely short bunch lengths present for laser-driven ion beams.

Heavy-Ion-Induced Lung Tumors: Dose- & LET-Dependence.

There is a limited published literature reporting dose-dependent data for in vivo tumorigenesis prevalence in different organs of various rodent models after exposure to low, single doses of charged particle beams. The goal of this study is to reduce uncertainties in estimating particle-radiation-induced risk of lung tumorigenesis for manned travel into deep space by improving our understanding of the high-LET-dependent dose-response from exposure to individual ion beams after low particle doses (0.03-0.

RRM1 variants cause a mitochondrial DNA maintenance disorder via impaired de novo nucleotide synthesis.

Mitochondrial DNA (mtDNA) depletion/deletions syndromes (MDDS) encompass a clinically and etiologically heterogenous group of mitochondrial disorders caused by impaired mtDNA maintenance. Among the most frequent causes of MDDS are defects in nucleoside/nucleotide metabolism, which is critical for synthesis and homeostasis of the deoxynucleoside triphosphate (dNTP) substrates of mtDNA replication. A central enzyme for generating dNTPs is ribonucleotide reductase, a critical mediator of de novo nucleotide synthesis composed of catalytic RRM1 subunits in complex with RRM2 or p53R2.

Roadmap: helium ion therapy.

Helium ion beam therapy for the treatment of cancer was one of several developed and studied particle treatments in the 1950s, leading to clinical trials beginning in 1975 at the Lawrence Berkeley National Laboratory. The trial shutdown was followed by decades of research and clinical silence on the topic while proton and carbon ion therapy made debuts at research facilities and academic hospitals worldwide. The lack of progression in understanding the principle facets of helium ion beam therapy in terms of physics, biological and clinical findings persists today, mainly attributable to its highly limited availability.

A new platform for ultra-high dose rate radiobiological research using the BELLA PW laser proton beamline.

Radiotherapy is the current standard of care for more than 50% of all cancer patients. Improvements in radiotherapy (RT) technology have increased tumor targeting and normal tissue sparing. Radiations at ultra-high dose rates required for FLASH-RT effects have sparked interest in potentially providing additional differential therapeutic benefits.

Forecasting stroke-like episodes and outcomes in mitochondrial disease.

In this retrospective, multicentre, observational cohort study, we sought to determine the clinical, radiological, EEG, genetics and neuropathological characteristics of mitochondrial stroke-like episodes and to identify associated risk predictors. Between January 1998 and June 2018, we identified 111 patients with genetically determined mitochondrial disease who developed stroke-like episodes. Post-mortem cases of mitochondrial disease (n = 26) were identified from Newcastle Brain Tissue Resource.

A proposed change to astronaut exposures limits is a giant leap backwards for radiation protection.

Addressing the uncertainties in assessing health risks from cosmic ray heavy ions is a major scientific challenge recognized by many previous reports by the National Academy of Sciences (NAS) and the National Council on Radiation Protection and Measurements (NCRP) advising the National Aeronautics and Space Administration (NASA). These reports suggested a series of steps to pursue the scientific basis for space radiation protection, including the implementation of age and sex dependent risk assessments and exposure limits appropriate for a small population of radiation workers, the evaluation of uncertainties in risk projections, and developing a vigorous research program in heavy ion radiobiology to reduce uncertainties and discover effective countermeasures. The assessment of uncertainties in assessing risk provides protection against changing assessments of risk, reveals limitations in information used in space mission operations, and provides the impetus to reduce uncertainties and discover the true level of risk and possible effectiveness of countermeasures through research.

Dominance Hierarchies in Marine Invertebrates.

AbstractDominance hierarchies have been well studied in myriad terrestrial animals, but surprisingly little is known about hierarchies in marine invertebrates; examples are limited to a few species of decapod crustaceans and cephalopods. Is the marine environment less conducive to the establishment of dominance hierarchy structures, or does this just underline the lack of detailed behavioral information about most marine invertebrates? In this review, we highlight the published information about marine invertebrate dominance hierarchies, which involve ranks established through fights or displays. We focus on the method of hierarchy formation, examine the ecological implications of this population structure, and compare the habitat and behavioral characteristics of species that exhibit this behavior.

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks.

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR Cs (40-160 cGy, 0.662 MeV), Si-IR (4-32 cGy, 260 MeV/n), or Ti-IR (3-26 cGy, 1 GeV/n).

POLRMT mutations impair mitochondrial transcription causing neurological disease.

While >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype.

The 20th Gray lecture 2019: health and heavy ions.

Objective: Particle radiobiology has contributed new understanding of radiation safety and underlying mechanisms of action to radiation oncology for the treatment of cancer, and to planning of radiation protection for space travel. This manuscript will highlight the significance of precise physical and biologically effective dosimetry to this translational research for the benefit of human health.This review provides a brief snapshot of the evolving scientific basis for, and the complex current global status, and remaining challenges of hadron therapy for the treatment of cancer.

Ultrasensitive deletion detection links mitochondrial DNA replication, disease, and aging.

Background: Acquired human mitochondrial genome (mtDNA) deletions are symptoms and drivers of focal mitochondrial respiratory deficiency, a pathological hallmark of aging and late-onset mitochondrial disease.

Results: To decipher connections between these processes, we create LostArc, an ultrasensitive method for quantifying deletions in circular mtDNA molecules. LostArc reveals 35 million deletions (~ 470,000 unique spans) in skeletal muscle from 22 individuals with and 19 individuals without pathogenic variants in POLG.

Simulating galactic cosmic ray effects: Synergy modeling of murine tumor prevalence after exposure to two one-ion beams in rapid sequence.

Health risks from galactic cosmic rays (GCR) in space travel above low earth orbit remain a concern. For many years accelerator experiments investigating space radiation induced prevalence of murine Harderian gland (HG) tumorigenesis have been performed to help estimate GCR risks. Most studies used acute, relatively low fluence, exposures.