Traumatic brain injury (TBI) is a growing public health problem worldwide and is a leading cause of death and disability. The causes of TBI include motor vehicle accidents, which are the most common ...cause, falls, acts of violence, sports-related head traumas, and war accidents including blast-related brain injuries. Recently, pituitary dysfunction has also been described in boxers and kickboxers. Neuroendocrine dysfunction due to TBI was described for the first time in 1918. Only case reports and small case series were reported until 2000, but since then pituitary function in TBI victims has been investigated in more detail. The frequency of hypopituitarism after TBI varies widely among different studies (15–50% of the patients with TBI in most studies). The estimates of persistent hypopituitarism decrease to 12% if repeated testing is applied. GH is the most common hormone lost after TBI, followed by ACTH, gonadotropins (FSH and LH), and TSH. The underlying mechanisms responsible for pituitary dysfunction after TBI are not entirely clear; however, recent studies have shown that genetic predisposition and autoimmunity may have a role. Hypopituitarism after TBI may have a negative impact on the pace or degree of functional recovery and cognition. What is not clear is whether treatment of hypopituitarism has a beneficial effect on specific function. In this review, the current data related to anterior pituitary dysfunction after TBI in adult patients are updated, and guidelines for the diagnosis, follow-up strategies, and therapeutic approaches are reported.
Neuroendocrine dysfunction following traumatic brain injury and aneurysmal subarachnoid hemorrhage may occur with a much higher prevalence than previously suspected. This sequela is a potentially ...serious but treatable complication of brain injury.
To review research on hypothalamopituitary dysfunction as an underdiagnosed consequence of traumatic brain injury and subarachnoid hemorrhage, the natural history of this complication, and the potential clinical and public health implications of posttraumatic hypopituitarism.
The MEDLINE database was searched for articles published between 2000 and 2007 using any combination of the terms traumatic brain injury or subarachnoid hemorrhage with pituitary, hypopituitarism, growth hormone deficiency, hypogonadism, hypocortisolism, hypothyroidism, or diabetes insipidus. The reference lists of articles identified by this search strategy were also searched. All articles reporting original data on endocrine outcomes after traumatic brain injury or aneurysmal subarachnoid hemorrhage in peer-reviewed journals with regard to prevalence, pathogenesis, risk factors, outcomes, and clinical course were selected. We pooled data and calculated prevalence rates and 95% confidence intervals (CIs).
We identified 19 studies including 1137 patients. The pooled prevalences of hypopituitarism in the chronic phase after traumatic brain injury and aneurysmal subarachnoid hemorrhage were 27.5% (95% confidence interval CI, 22.8%-28.9%) and 47% (95% CI, 37.4%-56.8%), respectively. The pooled prevalence of hypopituitarism was greater in patients with severe compared with those with mild or moderate traumatic brain injury. Early neuroendocrine abnormalities were transient in some patients while, less commonly, hypopituitarism evolved over time in others. Patients with posttraumatic hypopituitarism showed an impaired quality of life and an adverse metabolic profile.
Hypopituitarism is a common complication of both traumatic brain injury and aneurysmal subarachnoid hemorrhage and might contribute to morbidity and poor recovery after brain injury.
Metal–organic frameworks (MOFs) are emerging as an appealing class of highly tailorable electrically conducting materials with potential applications in optoelectronics. Yet, the realization of their ...proof‐of‐concept devices remains a daunting challenge, attributed to their poor electrical properties. Following recent work on a semiconducting Fe3(THT)2(NH4)3 (THT: 2,3,6,7,10,11‐triphenylenehexathiol) 2D MOF with record‐high mobility and band‐like charge transport, here, an Fe3(THT)2(NH4)3 MOF‐based photodetector operating in photoconductive mode capable of detecting a broad wavelength range from UV to NIR (400–1575 nm) is demonstrated. The narrow IR bandgap of the active layer (≈0.45 eV) constrains the performance of the photodetector at room temperature by band‐to‐band thermal excitation of charge carriers. At 77 K, the device performance is significantly improved; two orders of magnitude higher voltage responsivity, lower noise equivalent power, and higher specific detectivity of 7 × 108 cm Hz1/2 W−1 are achieved under 785 nm excitation. These figures of merit are retained over the analyzed spectral region (400–1575 nm) and are commensurate to those obtained with the first demonstrations of graphene‐ and black‐phosphorus‐based photodetectors. This work demonstrates the feasibility of integrating conjugated MOFs as an active element into broadband photodetectors, thus bridging the gap between materials' synthesis and technological applications.
2D metal–organic framework (MOF) films of Fe3(THT)2(NH4)3 are employed as an active element in a two‐terminal photodetector device, operating in the UV‐to‐NIR region. Owing to the small bandgap of the MOF samples (≈0.45 eV), the photodetectors are best operated at 77 K. This is attributed to the suppression of thermally activated charge carriers at low temperatures, leading to improved performance of the device.
The timescale of early land plant evolution Morris, Jennifer L.; Puttick, Mark N.; Clark, James W. ...
Proceedings of the National Academy of Sciences - PNAS,
03/2018, Letnik:
115, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth’s System. The sparseness of early land plant megafossils and ...stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte−tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for Viridiplantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within Viridiplantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian–Early Ordovician, origin.
Background:
The outcome of bilateral adrenalectomy (BADx) in patients with Cushing's syndrome (CS) is not well characterized.
Methods:
A literature search was performed with the search terms ...“bilateral adrenalectomy” or “total adrenalectomy” and “Cushing's” or “Cushing.” Immediate and long-term outcomes after BADx in CS were analyzed using descriptive statistics (median range).
Results:
From 549 screened publications, 37 studies met inclusion criteria (1320 patients, 82% having Cushing's disease CD, 13% having ectopic CS, and 5% having primary adrenal hyperplasia). Surgical morbidity and mortality of BADx (23 studies, 739 patients) were 18% (6–31) and 3% (0–15), respectively. In patients with CD, surgical mortality was below 1%. Although residual cortisol secretion due to accessory adrenal tissue or adrenal remnants was found in 3–34% (5 studies, 236 patients), less than 2% had a relapse of CS. Symptoms of hypercortisolism (eg, hypertension, obesity, or depression) improved in the majority of the patients after BADx (7 studies, 195 patients). The number of adrenal crises per 100 patient-years was 9.3 (6 studies, 203 patients). Nelson's syndrome occurred in 21% (0–47) of the patients (24 studies, 768 patients). Mortality (23 studies, 690 patients) was 17% (0–88) at a follow-up of 41 months (14–294). Remarkably, 46% of the patients died in the first year after surgery. The median ages at death were 62 years (CD) and 53 years (ectopic CS).
Conclusion:
BADx is relatively safe and provides adequate success. Excess mortality within the first year after surgery suggests that intensive clinical care for patients after BADx is warranted.
The evolutionary emergence of land plant body plans transformed the planet. However, our understanding of this formative episode is mired in the uncertainty associated with the phylogenetic ...relationships among bryophytes (hornworts, liverworts, and mosses) and tracheophytes (vascular plants). Here we attempt to clarify this problem by analyzing a large transcriptomic dataset with models that allow for compositional heterogeneity between sites. Zygnematophyceae is resolved as sister to land plants, but we obtain several distinct relationships between bryophytes and tracheophytes. Concatenated sequence analyses that can explicitly accommodate site-specific compositional heterogeneity give more support for a mosses-liverworts clade, “Setaphyta,” as the sister to all other land plants, and weak support for hornworts as the sister to all other land plants. Bryophyte monophyly is supported by gene concatenation analyses using models explicitly accommodating lineage-specific compositional heterogeneity and analyses of gene trees. Both maximum-likelihood analyses that compare the fit of each gene tree to proposed species trees and Bayesian supertree estimation based on gene trees support bryophyte monophyly. Of the 15 distinct rooted relationships for embryophytes, we reject all but three hypotheses, which differ only in the position of hornworts. Our results imply that the ancestral embryophyte was more complex than has been envisaged based on topologies recognizing liverworts as the sister lineage to all other embryophytes. This requires many phenotypic character losses and transformations in the liverwort lineage, diminishes inconsistency between phylogeny and the fossil record, and prompts re-evaluation of the phylogenetic affinity of early land plant fossils, the majority of which are considered stem tracheophytes.
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•Early land plant relationships are extremely uncertain•We resolve the “Setaphyta” clade of liverworts plus mosses•The simple body plan of liverworts results from loss of ancestral characters•The ancestral land plant was more complex
Puttick et al. resolve a “Setaphyta” clade uniting liverworts and mosses and support for bryophyte monophyly. Their results indicate that the ancestral land plant was more complex than has been envisaged based on phylogenies recognizing liverworts as the sister lineage to all other embryophytes.
Utilization of ferns by phytophagous insects is widely considered to be less common and less specialized compared to the phytophagous insect community feeding on angiosperms. In this study, this ...assumption is challenged by exploring the evolution of pteridophagy （fern-feeding） in the larval stages of sawflies （Symphyta）. To achieve this, phylogenetic frameworks were assembled based on published phylogenetic studies and newly reconstructed phylogenies based on cytochrome oxidase subunit I （COl） barcoding data that allowed the reconstruction of the ancestral feeding preferences by plotting reported host plants of sawflies. Evidence was found for two exclusively pteridophagous lineages of sawflies that probably originated before the Cretaceous Terrestrial Revolution, whereas the third lineage comprising several exclusively pteridophagous sawfly genera is nested in the derived sawfly clade feeding predominantly on eudicots. Thus, the evolution of pteridophagy in the cade was probably connected with the transformation of terrestrial habitats associated with the rise of angiosperms during the Cretaceous. The observed phylogenetic patterns are consistent with the hypothesis of ＂larval diet conservatism＂ resulting in the establishment of genera and lineages that feed exclusively, or at least predominantly, on conifers, eudicots, ferns, and monocots. Only a small percentage of sawfly genera were found to be polyphylophagous. The results suggest a low frequency of switches between host plants belonging to different major plant lineages such as angiosperms, conifers, and ferns. Successful switches between hosts belonging to different major lineages of land plants coincide with the reorganization of the phylogenetic composition of terrestrial vegetation in the late Mesozoic.
The geochemical carbon cycle is strongly influenced by life on land, principally through the effects of carbon sequestration and the weathering of calcium and magnesium silicates in surface rocks and ...soils. Knowing the time of origin of land plants and animals and also of key organ systems (e.g. plant vasculature, roots, wood) is crucial to understand the development of the carbon cycle and its effects on other Earth systems. Here, we compare evidence from fossils with calibrated molecular phylogenetic trees (timetrees) of living plants and arthropods. We show that different perspectives conflict in terms of the relative timing of events, the organisms involved and the pattern of diversification of various groups. Focusing on the fossil record, we highlight a number of key biases that underpin some of these conflicts, the most pervasive and far-reaching being the extent and nature of major facies changes in the rock record. These effects probably mask an earlier origin of life on land than is evident from certain classes of fossil data. If correct, this would have major implications in understanding the carbon cycle during the Early Palaeozoic.
Abstract
Quantum cascade lasers (QCL) have revolutionized the generation of mid-infrared light. Yet, the ultrafast carrier transport in mid-infrared QCLs has so far constituted a seemingly ...insurmountable obstacle for the formation of ultrashort light pulses. Here, we demonstrate that careful quantum design of the gain medium and control over the intermode beat synchronization enable transform-limited picosecond pulses from QCL frequency combs. Both an interferometric radio-frequency technique and second-order autocorrelation shed light on the pulse dynamics and confirm that mode-locked operation is achieved from threshold to rollover current. Furthermore, we show that both anti-phase and in-phase synchronized states exist in QCLs. Being electrically pumped and compact, mode-locked QCLs pave the way towards monolithically integrated non-linear photonics in the molecular fingerprint region beyond 6 μm wavelength.
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