The association of bilateral vestibulopathy with cerebellar ataxia was first reported in 1991 and delineated as a distinct syndrome with a characteristic and measurable clinical sign—an absent ...visually enhanced vestibulo‐ocular reflex—in 2004. We reviewed 27 patients with this syndrome and show that a non‐length‐dependent sensory deficit with absent sensory nerve action potentials is an integral component of this syndrome, which we now call “cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome” (CANVAS). All patients had brain MRI and 22/27 had evidence of cerebellar atrophy involving anterior and dorsal vermis, as well as the hemispheric crus I. Brain and temporal bone pathology in one patient showed marked loss of Purkinje cells and of vestibular, trigeminal, and facial ganglion cells, but not of spiral ganglion cells. There are two sets of sibling pairs, suggesting CANVAS is a late‐onset recessive disorder. The characteristic clinical sign—the visual vestibulo‐ocular reflex deficit—can be demonstrated and measured clinically using video‐oculography.
Breaking away from the linear structure of previously reported peptide‐based gelators, this study reports the first example of gel formation based on the use of cyclic peptides made of alternating d‐ ...and l‐amino acids, known to self‐assemble in solution to form long nanotubes. Herein, a library of cyclic peptides was systemically studied for their gelation properties in various solvents, uncovering key parameters driving both organogel and hydrogel formation. The hierarchical nature of the self‐assembly process in water was characterised by a combination of electron microscopy imaging and small‐angle X‐ray scattering, revealing a porous network of entangled nanofibres composed by the aggregation of several cyclic peptide nanotubes. Rheology measurements then confirmed the formation of soft hydrogels.
Getting in formation: This study reports the first example of gel formation based on the use of cyclic peptides made of alternating d‐ and l‐ amino acids, which self‐assemble in solution to form long nanotubes. Herein, a library of cyclic peptides was systemically studied for their gelation properties in various solvents, uncovering key parameters driving both organogel and hydrogel formation.
Mutation of the X-linked oral-facial-digital syndrome type 1 (OFD1) gene is embryonic lethal in males and results in craniofacial malformations and adult onset polycystic kidney disease in females. ...While the OFD1 protein localizes to centriolar satellites, centrosomes and basal bodies, its cellular function and how it relates to cystic kidney disease is largely unknown. Here, we demonstrate that OFD1 is assembled into a protein complex that is localized to the primary cilium and contains the epidermal growth factor receptor (EGFR) and domain organizing flotillin proteins. This protein complex, which has similarity to a basolateral adhesion domain formed during cell polarization, also contains the polycystin proteins that when mutant cause autosomal dominant polycystic kidney disease (ADPKD). Importantly, in human ADPKD cells where mutant polycystin-1 fails to localize to cilia, there is a concomitant loss of localization of polycystin-2, OFD1, EGFR and flotillin-1 to cilia. Together, these data suggest that polycystins are necessary for assembly of a novel flotillin-containing ciliary signaling complex and provide a molecular rationale for the common renal pathologies caused by OFD1 and PKD mutations.
Anthropogenic stressors, such as urban development and intensification of agricultural and industrial activities, can alter physical, chemical, and biological conditions in aquatic systems. Mounting ...concern over cumulative effects of multiple stressors has stimulated the need to track ecological responses and quantify degradation. Periphytic diatoms have potential to serve as early indicators of ecological degradation in aquatic systems. We examined relations between periphytic diatom community composition, water chemistry, and the magnitude of anthropogenic stressors in lakes of the Muskoka River watershed. These relations were used to develop a bioassessment framework for tracking changes in biological integrity in a region undergoing growth of tourism and related urban and recreational activities. We examined nearshore periphyton and water-chemistry samples from 86 lakes to assess relations between diatom community composition, water chemistry, and measures of 9 anthropogenic stressors (e.g., % urban area, % agricultural area, roadway proximity) based on uni- and multivariate numerical methods. Composition of periphytic diatom communities was associated with the concentration of ions from anthropogenic sources (i.e., road salt, dust suppressants). We demonstrated that periphytic diatoms in the nearshore regions of the lakes may be sensitive early warning indicators of ecological change because the most dramatic shift in diatom community composition was observed with modest increases in anthropogenic stressors. This relationship was weaker at sites where natural variation in pH among lakes was high. pH often acts in conjunction with other chemical factors to influence diatom community composition. Thus, we recommend stratifying monitoring efforts to account for confounding natural variation in pH. We anticipate that periphytic diatoms can be used as a powerful indicator of environmental stress in lakes beyond the MRW.
Trainees in oncology learn about ionising radiation, but to understand it fully they must also understand the physics relevant to its use in therapy. This is the first book written specifically for ...the oncology and radiation team. It begins with basic concepts and then explores the principles and practice of physics as it relates to radiotherapy, including discussion of specific types of therapy. ABOUT THE SERIES: Radiotherapy remains the major non-surgical treatment modality for the management of malignant disease. It is based on the application of the principles of applied physics, radiobiology, and tumour biology to clinical practice. Each volume in this series takes the reader through the basic principles of the use of ionising radiation and then develops this by individual sites. This series of practical handbooks are aimed at physicians both training and practising in radiotherapy, as well asmedical physicists, dosimetrists, radiographers and senior nurses.
Leaf traits are frequently measured in ecology to provide a 'common currency' for predicting how anthropogenic pressures impact ecosystem function. Here, we test whether leaf traits consistently ...respond to experimental treatments across 27 globally distributed grassland sites across 4 continents. We find that specific leaf area (leaf area per unit mass)-a commonly measured morphological trait inferring shifts between plant growth strategies-did not respond to up to four years of soil nutrient additions. Leaf nitrogen, phosphorus and potassium concentrations increased in response to the addition of each respective soil nutrient. We found few significant changes in leaf traits when vertebrate herbivores were excluded in the short-term. Leaf nitrogen and potassium concentrations were positively correlated with species turnover, suggesting that interspecific trait variation was a significant predictor of leaf nitrogen and potassium, but not of leaf phosphorus concentration. Climatic conditions and pretreatment soil nutrient levels also accounted for significant amounts of variation in the leaf traits measured. Overall, we find that leaf morphological traits, such as specific leaf area, are not appropriate indicators of plant response to anthropogenic perturbations in grasslands.
To be able to perform radiotherapy effectively, oncologists and radiographers need to understand the physics behind it. This book is the first on radiation physics written specifically for the needs ...of the practising oncology team.
We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost ...region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon–climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km² for the RCP4.5 climate and between 6 and 16 million km² for the RCP8.5 climate. For the RCP4.5 projection, cumulative change in soil carbon varied between 66-Pg C (1015-g carbon) loss to 70-Pg C gain. For the RCP8.5 projection, losses in soil carbon varied between 74 and 652 Pg C (mean loss, 341 Pg C). For the RCP4.5 projection, gains in vegetation carbon were largely responsible for the overall projected net gains in ecosystem carbon by 2299 (8- to 244-Pg C gains). In contrast, for the RCP8.5 projection, gains in vegetation carbon were not great enough to compensate for the losses of carbon projected by four of the five models; changes in ecosystem carbon ranged from a 641-Pg C loss to a 167-Pg C gain (mean, 208-Pg C loss). The models indicate that substantial net losses of ecosystem carbon would not occur until after 2100. This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.
Abstract
In 2017, the California-Kepler Survey (CKS) published its first data release (DR1) of high-resolution optical spectra of 1305 planet hosts. Refined CKS planet radii revealed that small ...planets are bifurcated into two distinct populations, super-Earths (smaller than 1.5
R
⊕
) and sub-Neptunes (between 2.0 and 4.0
R
⊕
), with few planets in between (the “radius gap”). Several theoretical models of the radius gap predict variation with stellar mass, but testing these predictions is challenging with CKS DR1 due to its limited
M
⋆
range of 0.8–1.4
M
⊙
. Here we present CKS DR2 with 411 additional spectra and derived properties focusing on stars of 0.5–0.8
M
⊙
. We found that the radius gap follows
R
p
∝
P
m
with
m
= −0.10 ± 0.03, consistent with predictions of X-ray and ultraviolet- and core-powered mass-loss mechanisms. We found no evidence that
m
varies with
M
⋆
. We observed a correlation between the average sub-Neptune size and
M
⋆
. Over 0.5–1.4
M
⊙
, the average sub-Neptune grows from 2.1 to 2.6
R
⊕
, following
R
p
∝
M
⋆
α
with
α
= 0.25 ± 0.03. In contrast, there is no detectable change for super-Earths. These
M
⋆
–
R
p
trends suggest that protoplanetary disks can efficiently produce cores up to a threshold mass of
M
c
, which grows linearly with stellar mass according to
M
c
≈ 10
M
⊕
(
M
⋆
/
M
⊙
). There is no significant correlation between sub-Neptune size and stellar metallicity (over −0.5 to +0.5 dex), suggesting a weak relationship between planet envelope opacity and stellar metallicity. Finally, there is no significant variation in sub-Neptune size with stellar age (over 1–10 Gyr), which suggests that the majority of envelope contraction concludes after ∼1 Gyr.
PDF
