Many species are classified as Data Deficient, because there is a knowledge gap about distribution range and population size and trends.
This situation may be a problem in conservation, because the ...extinction risk of these species is unknown. In the present study, we analyzed all Brazilian anuran species classified as Data Deficient in the IUCN Red List to propose a method to know the conservation status of Data Deficient species. We used the time since species description coupled with the known current species distribution size to indicate the potential conservation status of Data Deficient species. We considered 231 Data Deficient anuran species in Brazil, in which most species (n=166 spp.) are newly described and restricted geographically (Group D). Group A (n=9 spp.) and C (n=18 spp.) were composed by species widely distributed and Group B (n=37 spp.) was composed by species described more than 50years ago and geographically restricted. Data Deficient is not a threatened category, however it indicates a need to obtain more information about the species listed, but unfortunately financial resource is limited. We suggested that the species allocated in the group B in our analyses must be priorities in future studies, because it is possible that these are threatened. Our analysis used the amphibian anuran from Brazil as model to propose some action that may be useful to known the conservation status of Data Deficient species.
Private umbilical cord blood banking is a for-profit industry in which parents pay to store blood for potential future use. Governments have noted the tendency for private banks to oversell the ...potential for cord blood use, especially in relation to speculative cell therapies not yet supported by clinical evidence. We assessed the regulatory landscape governing private cord bank marketing in Canada. Private cord blood bank marketing that advertises hypothetical future treatments can be misleading and may influence consumer behaviour. This marketing may breach existing advertising law. Regulatory bodies should enforce the law in order to help prevent public health and personal financial harm.
Relaxor ferroelectrics are important in technological applications due to strong electromechanical response, energy storage capacity, electrocaloric effect, and pyroelectric energy conversion ...properties. Current efforts to discover and design materials in this class generally rely on substitutional doping as slight changes to local compositional order can significantly affect the Curie temperature, morphotropic phase boundary, and electromechanical responses. In this work, we demonstrate that moving to the strong limit of compositional complexity in an ABO3 perovskite allows stabilization of relaxor responses that do not rely on a single narrow phase transition region. Entropy-assisted synthesis approaches are utilized to synthesize single-crystal Ba(Ti0.2Sn0.2Zr0.2Hf0.2Nb0.2)O3 Ba(5B)O films. The high levels of configurational disorder present in this system are found to influence dielectric relaxation, phase transitions, nanopolar domain formation, and Curie temperature. Temperature-dependent dielectric, Raman spectroscopy, and second-harmonic generation measurements reveal multiple phase transitions, a high Curie temperature of 570 K, and the relaxor ferroelectric nature of Ba(5B)O films. The first-principles theory calculations are used to predict possible combinations of cations to design relaxor ferroelectrics and quantify the relative feasibility of synthesizing these highly disordered single-phase perovskite systems. The ability to stabilize single-phase perovskites with various cations on the B-sites offers possibilities for designing high-performance relaxor ferroelectric materials for piezoelectric, pyroelectric, and electrocaloric applications.
Design of hardware based on biological principles of neuronal computation and plasticity in the brain is a leading approach to realizing energy- and sample-efficient AI and learning machines. An ...important factor in selection of the hardware building blocks is the identification of candidate materials with physical properties suitable to emulate the large dynamic ranges and varied timescales of neuronal signaling. Previous work has shown that the all-or-none spiking behavior of neurons can be mimicked by threshold switches utilizing material phase transitions. Here, we demonstrate that devices based on a prototypical metal-insulator-transition material, vanadium dioxide (VO
), can be dynamically controlled to access a continuum of intermediate resistance states. Furthermore, the timescale of their intrinsic relaxation can be configured to match a range of biologically relevant timescales from milliseconds to seconds. We exploit these device properties to emulate three aspects of neuronal analog computation: fast (~1 ms) spiking in a neuronal soma compartment, slow (~100 ms) spiking in a dendritic compartment, and ultraslow (~1 s) biochemical signaling involved in temporal credit assignment for a recently discovered biological mechanism of one-shot learning. Simulations show that an artificial neural network using properties of VO
devices to control an agent navigating a spatial environment can learn an efficient path to a reward in up to fourfold fewer trials than standard methods. The phase relaxations described in our study may be engineered in a variety of materials and can be controlled by thermal, electrical, or optical stimuli, suggesting further opportunities to emulate biological learning in neuromorphic hardware.
In magnetic systems, spin and exchange disorder can provide access to quantum criticality, frustration, and spin dynamics, but broad tunability of these responses and a deeper understanding of strong ...limit disorder are lacking. Here, it is demonstrated that high entropy oxides present a previously unexplored route to designing materials in which the presence of strong local compositional disorder may be exploited to generate tunable magnetic behaviors—from macroscopically ordered states to frustration‐driven dynamic spin interactions. Single‐crystal La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 films are used as a model system hosting a magnetic sublattice with a high degree of microstate disorder in the form of site‐to‐site spin and exchange type inhomogeneity. A classical Heisenberg model simplified to represent the highest probability microstates well describes how compositionally disordered systems can paradoxically host magnetic uniformity and demonstrates a path toward continuous control over ordering types and critical temperatures. Model‐predicted materials are synthesized and found to possess an incipient quantum critical point when magnetic ordering types are designed to be in direct competition, this leads to highly controllable exchange bias behaviors previously accessible only in intentionally designed bilayer heterojunctions.
High entropy oxides provide a previously unexplored route to designing magnetic behaviors not possible in less complex materials. Theoretical predictive models are developed and used to inform single‐crystal film synthesis to gain continuously tunable access to a full range of magnetic states—from antiferromagnetism to ferromagnetism to frustrated dynamical magnetism.
As the energy demand is expected to double over the next 30 years, there has been a major initiative towards advancing the technology of both energy harvesting and storage for renewable energy. In ...this work, we explore a subset class of dielectrics for energy storage since ferroelectrics offer a unique combination of characteristics needed for energy storage devices. We investigate ferroelectric lead-free 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 epitaxial thin films with different crystallographic orientations grown by pulsed laser deposition. We focus our attention on the influence of the crystallographic orientation on the microstructure, ferroelectric, and dielectric properties. Our results indicate an enhancement of the polarization and strong anisotropy in the dielectric response for the (001)-oriented film. The enhanced ferroelectric, energy storage, and dielectric properties of the (001)-oriented film is explained by the coexistence of orthorhombic-tetragonal phase, where the disordered local structure is in its free energy minimum.
High entropy oxides are emerging as an exciting new avenue to design highly tailored functional behaviors that have no traditional counterparts. Study and application of these materials are bringing ...together scientists and engineers from physics, chemistry, and materials science. The diversity of each of these disciplines comes with perspectives and jargon that may be confusing to those outside of the individual fields, which can result in miscommunication of important aspects of research. In this Perspective, we provide examples of research and characterization taken from these different fields to provide a framework for classifying the differences between compositionally complex oxides, high entropy oxides, and entropy stabilized oxides, which is intended to bring a common language to this emerging area. We highlight the critical importance of understanding a material’s crystallinity, composition, and mixing length scales in determining its true definition.
Preventing Microalbuminuria in Type 2 Diabetes Ruggenenti, Piero; Fassi, Anna; Ilieva, Anelja Parvanova ...
The New England journal of medicine,
11/2004, Letnik:
351, Številka:
19
Journal Article
Recenzirano
Odprti dostop
In a multicenter, double-blind, placebo-controlled, randomized study, subjects with type 2 diabetes mellitus and hypertension but normal urinary albumin levels were treated with an ...angiotensin-converting–enzyme (ACE) inhibitor (trandolapril) and a non-dihydropyridine calcium-channel blocker (verapamil) alone or in combination to investigate whether treatment could forestall the development of microalbuminuria, which heralds diabetic nephropathy. The use of trandolapril alone or with verapamil appeared to be effective, whereas verapamil alone was no better than placebo.
ACE inhibition may prevent or retard the development of microalbuminuria in patients with type 2 diabetes mellitus.
Type 2 diabetes mellitus is a public health concern, and projections of its future effect are alarming. According to the World Health Organization, diabetes affects more than 170 million people worldwide, and this number will rise to 370 million by 2030.
1
About one third of those affected will eventually have progressive deterioration of renal function.
2
The first clinical sign of renal dysfunction in patients with diabetes is generally microalbuminuria (a sign of endothelial dysfunction that is not necessarily confined to the kidney),
4
which develops in 2 to 5 percent of patients per year.
5
,
6
In type 2 diabetes, unlike type . . .
Gene therapy might represent a promising strategy for chondral and osteochondral defects repair by balancing the management of temporary joint mechanical incompetence with altered metabolic and ...inflammatory homeostasis. This review analysed preclinical and clinical studies on gene therapy for the repair of articular cartilage defects performed over the last 10 years, focussing on expression vectors (non-viral and viral), type of genes delivered and gene therapy procedures (direct or indirect). Plasmids (non-viral expression vectors) and adenovirus (viral vectors) were the most employed vectors in preclinical studies. Genes delivered encoded mainly for growth factors, followed by transcription factors, anti-inflammatory cytokines and, less frequently, by cell signalling proteins, matrix proteins and receptors. Direct injection of the expression vector was used less than indirect injection of cells, with or without scaffolds, transduced with genes of interest and then implanted into the lesion site. Clinical trials (phases I, II or III) on safety, biological activity, efficacy, toxicity or bio-distribution employed adenovirus viral vectors to deliver growth factors or anti-inflammatory cytokines, for the treatment of osteoarthritis or degenerative arthritis, and tumour necrosis factor receptor or interferon for the treatment of inflammatory arthritis.
The coexistence of nonvolatile and volatile switching modes in a single memristive device provides flexibility to emulate both neuronal and synaptic functions in the brain. Furthermore, such a device ...structure may eliminate the need for additional circuit elements such as transistor-based selectors, enabling low-power consumption and high-density device integration in fully memristive spiking neural networks. In this work, we report dual resistive switching (RS) modes in VO
/La
Sr
MnO
(LSMO) bilayer memristive devices. Specifically, the nonvolatile RS is driven by the movement of oxygen vacancies (V
) at the VO
/LSMO interface and requires a higher biasing voltage, whereas the volatile RS is controlled by the metal-insulator transition (MIT) of VO
under a lower biasing voltage. The simple device structure is electrically driven between the two RS modes and thus can operate as a one selector-one resistor (1S1R) cell, which is a desirable feature in memristive crossbar arrays to avoid the sneak-path current issue. The RS modes are found to be stable and repeatable and can be reconfigured by exploiting the interfacial and phase transition properties, and thus, they hold great promise for applications in memristive neural networks and neuromorphic computing.
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