Fungi are morphologically, ecologically, metabolically, and phylogenetically diverse. They are known to produce numerous bioactive molecules, which makes them very useful for natural products ...researchers in their pursuit of discovering new chemical diversity with agricultural, industrial, and pharmaceutical applications. Despite their importance in natural products chemistry, identification of fungi remains a daunting task for chemists, especially those who do not work with a trained mycologist. The purpose of this review is to update natural products researchers about the tools available for molecular identification of fungi. In particular, we discuss (1) problems of using morphology alone in the identification of fungi to the species level; (2) the three nuclear ribosomal genes most commonly used in fungal identification and the potential advantages and limitations of the ITS region, which is the official DNA barcoding marker for species-level identification of fungi; (3) how to use NCBI-BLAST search for DNA barcoding, with a cautionary note regarding its limitations; (4) the numerous curated molecular databases containing fungal sequences; (5) the various protein-coding genes used to augment or supplant ITS in species-level identification of certain fungal groups; and (6) methods used in the construction of phylogenetic trees from DNA sequences to facilitate fungal species identification. We recommend that, whenever possible, both morphology and molecular data be used for fungal identification. Our goal is that this review will provide a set of standardized procedures for the molecular identification of fungi that can be utilized by the natural products research community.
► Land use change impact on hydrology in a small watershed in Kenya is examined. ► The Soil and Water Assessment Tool is used to model hydrologic response to land use change. ► Impact of land use ...change on groundwater recharge and implications for community water sourcing and Lake Nakuru are addressed.
Land cover and land use changes in Kenya’s Rift Valley have altered the hydrologic response of the River Njoro watershed by changing the partitioning of excess rainfall into surface discharge and groundwater recharge. The watershed contributes a significant amount of water to Lake Nakuru National Park, an internationally recognized Ramsar site, as well as groundwater supplies for local communities and the city of Nakuru. Three land use maps representing a 17-year period when the region underwent significant transitions served as inputs for hydrologic modeling using the Automated Geospatial Watershed Assessment (AGWA) tool, a GIS-based hydrologic modeling system. AGWA was used to parameterize the Soil and Water Assessment Tool (SWAT), a hydrologic model suitable for assessing the relative impact of land cover change on hydrologic response. The SWAT model was calibrated using observation data taken during the 1990s with high annual concordance. Simulation results showed that land use changes have resulted in corresponding increases in surface runoff and decreases in groundwater recharge. Hydrologic changes were highly variable both spatially and temporally, and the uppermost reaches of the forested highlands were most significantly affected. These changes have negative implications for the ecological health of the river system as well as Lake Nakuru and local communities.
A carotid-cavernous fistula (CCF) is an abnormal communication between arteries and veins within the cavernous sinus and may be classified as either direct or dural. Direct CCFs are characterized by ...a direct connection between the internal carotid artery (ICA) and the cavernous sinus, whereas dural CCFs result from an indirect connection involving cavernous arterial branches and the cavernous sinus. Direct CCFs frequently are traumatic in origin and also may be caused by rupture of an ICA aneurysm within the cavernous sinus, Ehlers-Danlos syndrome type IV, or iatrogenic intervention. Causes of dural CCFs include hypertension, fibromuscular dysplasia, Ehlers-Danlos type IV, and dissection of the ICA. Evaluation of a suspected CCF often involves non-invasive imaging techniques, including standard tonometry, pneumotonometry, ultrasound, computed tomographic scanning and angiography, and/or magnetic resonance imaging and angiography, but the gold standard for classification and diagnosis remains digital subtraction angiography. When a direct CCF is confirmed, first-line treatment is endovascular intervention, which may be accomplished using detachable balloons, coils, liquid embolic agents, or a combination of these tools. As dural CCFs often resolve spontaneously, low-risk cases may be managed conservatively. When invasive treatment is warranted, endovascular intervention or stereotactic radiosurgery may be performed. Modern endovascular techniques offer the ability to successfully treat CCFs with a low morbidity and virtually no mortality.
Biodegradable Piezoelectric Force Sensor Curry, Eli J.; Ke, Kai; Chorsi, Meysam T. ...
Proceedings of the National Academy of Sciences,
01/2018, Letnik:
115, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using ...mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-L-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0–18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.
Two-pore domain potassium (K⁺) channels (K2P channels) control the negative resting potential of eukaryotic cells and regulate cell excitability by conducting K⁺ ions across the plasma membrane.Here, ...we present the 3.4 angstrom resolution crystal structure of a human K2P channel, K2P1 (TWIK-1).Unlike other K⁺ channel structures, K2P1 is dimeric. An extracellular cap domain located above the selectivity filter forms an ion pathway in which K ions flow through side portals. Openings within the transmembrane region expose the pore to the lipid bilayer and are filled with electron density attributable to alkyl chains. An interfacial helix appears structurally poised to affect gating. The structure lays a foundation to further investigate how K2P channels are regulated by diverse stimuli.
Surfaces decorated with uniformly dispersed catalytically active nanoparticles play a key role in many fields, including renewable energy and catalysis. Typically, these structures are prepared by ...deposition techniques, but alternatively they could be made by growing the nanoparticles in situ directly from the (porous) backbone support. Here we demonstrate that growing nano-size phases from perovskites can be controlled through judicious choice of composition, particularly by tuning deviations from the ideal ABO3 stoichiometry. This non-stoichiometry facilitates a change in equilibrium position to make particle exsolution much more dynamic, enabling the preparation of compositionally diverse nanoparticles (that is, metallic, oxides or mixtures) and seems to afford unprecedented control over particle size, distribution and surface anchorage. The phenomenon is also shown to be influenced strongly by surface reorganization characteristics. The concept exemplified here may serve in the design and development of more sophisticated oxide materials with advanced functionality across a range of possible domains of application.
Nonarteritic anterior ischaemic optic neuropathy (NAION) is the most common acute optic neuropathy in patients over the age of 50 and is the second most common cause of permanent optic nerve-related ...visual loss in adults after glaucoma. Patients typically present with acute, painless, unilateral loss of vision associated with a variable visual field defect, a relative afferent pupillary defect, a swollen, hyperaemic optic disc, and one or more flame-shaped peripapillary retinal haemorrhages. The pathogenesis of this condition is unknown, but it occurs primarily in patients with structurally small optic discs that have little or no cup and a variety of underlying vascular disorders that may or may not be known at the time of visual loss. There is no consistently beneficial medical or surgical treatment for the condition, but there are now animal models that allow testing of various potential therapies. About 40% of patients experience spontaneous improvement in visual acuity. Patients in whom NAION occurs in one eye have a 15-19% risk of developing a similar event in the opposite eye over the subsequent 5 years.
Cultural history is increasingly informed by the history of material culture-the ways in which individuals or entire societies create and relate to objects both mundane and extraordinary-rather than ...on textual evidence alone. Books such asThe Hare with Amber EyesandA History of the World in 100 Objectsindicate the growing popularity of this way of understanding the past. InHistory and Its Objects, Peter N. Miller uncovers the forgotten origins of our fascination with exploring the past through its artifacts by highlighting the role of antiquarianism-a pursuit ignored and derided by modem academic history-in grasping the significance of material culture.
From the efforts of Renaissance antiquarians, who reconstructed life in the ancient world from coins, inscriptions, seals, and other detritus, to amateur historians in the nineteenth century working within burgeoning national traditions, Miller connects collecting-whether by individuals or institutions-to the professionalization of the historical profession, one which came to regard its progenitors with skepticism and disdain. The struggle to articulate the value of objects as historical evidence, then, lies at the heart both of academic history-writing and of the popular engagement with things. Ultimately, this book demonstrates that our current preoccupation with objects is far from novel and reflects a human need to reexperience the past as a physical presence.
Melting of the world's major ice sheets can affect human and environmental conditions by contributing to sea-level rise. In July 2012, an historically rare period of extended surface melting was ...observed across almost the entire Greenland ice sheet, raising questions about the frequency and spatial extent of such events. Here we show that low-level clouds consisting of liquid water droplets ('liquid clouds'), via their radiative effects, played a key part in this melt event by increasing near-surface temperatures. We used a suite of surface-based observations, remote sensing data, and a surface energy-balance model. At the critical surface melt time, the clouds were optically thick enough and low enough to enhance the downwelling infrared flux at the surface. At the same time they were optically thin enough to allow sufficient solar radiation to penetrate through them and raise surface temperatures above the melting point. Outside this narrow range in cloud optical thickness, the radiative contribution to the surface energy budget would have been diminished, and the spatial extent of this melting event would have been smaller. We further show that these thin, low-level liquid clouds occur frequently, both over Greenland and across the Arctic, being present around 30-50 per cent of the time. Our results may help to explain the difficulties that global climate models have in simulating the Arctic surface energy budget, particularly as models tend to under-predict the formation of optically thin liquid clouds at supercooled temperatures--a process potentially necessary to account fully for temperature feedbacks in a warming Arctic climate.
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