This paper reviews recent advances in chemical synthesis, self‐assembly, and potential applications of monodisperse binary FePt nanoparticles. After a brief introduction to nanomagnetism and ...conventional processes of fabricating FePt nanoparticles, the paper focuses on recent developments in solution‐phase syntheses of monodisperse FePt nanoparticles and their self‐assembly into nanoparticle superlattices. The paper further outlines the surface, structural, and magnetic properties of the FePt nanoparticles and gives examples of three potential applications in data storage, permanent magnetic nanocomposites, and biomedicine.
Monodisperse FePt nanoparticles (see Figure) are sought after for their potential applications in data storage, permanent magnetic nanocomposites, and biomedicine. This Review highlights recent developments in their solution‐phase synthesis and assembly, and further outlines their surface, structural, and magnetic properties.
Protein ubiquitination is a reversible reaction, in which the ubiquitin chains are deconjugated by a family of deubiquitinases (DUBs). The presence of a large number of DUBs suggests that they likely ...possess certain levels of substrate selectivity and functional specificity. Indeed, recent studies show that a tumor suppressor DUB, cylindromatosis (CYLD), has a predominant role in the regulation of NF-kappaB, a transcription factor that promotes cell survival and oncogenesis. NF-kappaB activation involves attachment of K63-linked ubiquitin chains to its upstream signaling factors, which is thought to facilitate protein-protein interactions in the assembly of signaling complexes. By deconjugating these K63-linked ubiquitin chains, CYLD negatively regulates NF-kappaB activation, which may contribute to its tumor suppressor function. CYLD also regulates diverse physiological processes, ranging from immune response and inflammation to cell cycle progression, spermatogenesis, and osteoclastogenesis. Interestingly, CYLD itself is subject to different mechanisms of regulation.
In vitro and in vivo studies of anesthetics have demonstrated serious neurotoxic effects on the developing brain. However, the clinical relevance of these findings to children undergoing anesthesia ...remains unclear. Using data from a sibling birth cohort, we assessed the association between exposure to anesthesia in the setting of surgery in patients younger than 3 years and the risk of developmental and behavioral disorders.
We constructed a retrospective cohort of 10,450 siblings who were born between 1999 and 2005 and who were enrolled in the New York State Medicaid program. The exposed group was 304 children without a history of developmental or behavioral disorders who underwent surgery when they were younger than 3 years. The unexposed group was 10,146 children who did not receive any surgical procedures when they were younger than 3 years. Exposed children were entered into analysis at the date of surgery. Unexposed children were entered into analysis at age 10 months (the mean age at which exposed children underwent surgery). Both exposed and unexposed children were followed until diagnosis with a developmental or behavioral disorder, loss to follow-up, or the end of 2005. The association of exposure to anesthesia with subsequent developmental and behavioral disorders was assessed with both proportional hazards modeling, and pair-matched analysis.
The incidence of developmental and behavioral disorders was 128.2 diagnoses per 1000 person-years for the exposed cohort and 56.3 diagnoses per 1000 person-years for the unexposed cohort. With adjustment for sex and history of birth-related medical complications, and clustering by sibling status, the estimated hazard ratio of developmental or behavioral disorders associated with any exposure to anesthesia when they were younger than 3 years was 1.6 (95% confidence interval CI: 1.4, 1.8). The risk increased from 1.1 (95% CI: 0.8, 1.4) for 1 operation to 2.9 (94% CI: 2.5, 3.1) for 2 operations and 4.0 (95% CI: 3.5, 4.5) for ≥3 operations. The relative risk in a matched analysis of 138 sibling pairs was 0.9 (95% CI: 0.6, 1.4).
The risk of being subsequently diagnosed with developmental and behavioral disorders in children who were enrolled in a state Medicaid program and who had surgery when they were younger than 3 years was 60% greater than that of a similar group of siblings who did not undergo surgery. More tightly matched pairwise analyses indicate that the extent to which the excess risk is causally attributable to anesthesia or mediated by unmeasured factors remains to be determined.
Spatial patterns in trait variation reflect underlying community assembly processes, allowing us to test hypotheses about their trait and environmental drivers by identifying the strongest correlates ...of characteristic spatial patterns. For 43 evergreen tree species (> 1cm dbh) in a 20 ha seasonal tropical rainforest plot in Xishuangbanna, China, we compared the ability of drought tolerance traits, other physiological traits and commonly measured functional traits to predict the spatial patterns expected from the assembly processes of habitat associations, niche overlap-based competition, and hierarchical competition. We distinguished the neighborhood-scale (0- 20m) patterns expected from competition from larger-scale habitat associations with a wavelet method. Species' drought tolerance and habitat variables related to soil water supply were strong drivers of habitat associations, and drought tolerance showed a significant spatial signal for influencing competition. Overall, the traits most strongly associated with habitat, as quantified using multivariate models, were leaf density, leaf turgor loss point (πtlp; also known as the leaf wilting point), and stem hydraulic conductivity (r2 range for the best fit models = 0.27-0.36). At neighborhood scales, species spatial associations were positively correlated with similarity in πtlp, consistent with predictions for hierarchical competition. Although the correlation between πtlp and interspecific spatial associations was weak (r2 < 0.01), this showed a persistent influence of drought tolerance on neighborhood interactions and community assembly. Quantifying the full impact of traits on competitive interactions in forests may require incorporating plasticity among individuals within species, especially among specific life stages, and moving beyond individual traits to integrate the impact of multiple traits on whole-plant performance and resource demand.
A recent U.S. Food and Drug Administration warning advised that prolonged or repeated exposure to general anesthetics may affect neurodevelopment in children. This warning is based on a wealth of ...preclinical animal studies and relatively few human studies. The human studies include a variety of different populations with several different outcome measures. Interpreting the results requires consideration of the outcome used, the power of the study, the length of exposure and the efforts to reduce the confounding effects of comorbidity and surgery. Most, but not all, of the large population-based studies find evidence for associations between surgery in early childhood and slightly worse subsequent academic achievement or increased risk for later diagnosis of a behavioral disability. In several studies, the amount of added risk is very small; however, there is some evidence for a greater association with multiple exposures. These results may be consistent with the preclinical data, but the possibility of confounding means the positive associations can only be regarded as weak evidence for causation. Finally, there is strong evidence that brief exposure is not associated with any long term risk in humans.
Understanding how antibiotic use drives resistance is crucial for guiding effective strategies to limit the spread of resistance, but the use-resistance relationship across pathogens and antibiotics ...remains unclear. We applied sinusoidal models to evaluate the seasonal use-resistance relationship across 3 species (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and 5 antibiotic classes (penicillins, macrolides, quinolones, tetracyclines, and nitrofurans) in Boston, Massachusetts. Outpatient use of all 5 classes and resistance in inpatient and outpatient isolates in 9 of 15 species-antibiotic combinations showed statistically significant amplitudes of seasonality (false discovery rate (FDR) < 0.05). While seasonal peaks in use varied by class, resistance in all 9 species-antibiotic combinations peaked in the winter and spring. The correlations between seasonal use and resistance thus varied widely, with resistance to all antibiotic classes being most positively correlated with use of the winter peaking classes (penicillins and macrolides). These findings challenge the simple model of antibiotic use independently selecting for resistance and suggest that stewardship strategies will not be equally effective across all species and antibiotics. Rather, seasonal selection for resistance across multiple antibiotic classes may be dominated by use of the most highly prescribed antibiotic classes, penicillins and macrolides.
The hydrodynamic problem of a two dimensional wedge entering waves with gravity effect is analysed based on the incompressible velocity potential theory. The problem is solved through the boundary ...element method in the time domain. The stretched coordinate system in the spatial domain, which is based on the ratio of the Cartesian system in the physic space to the vertical distance the wedge has travelled into the water, is adopted based on the consideration that the decay of the effect of the impact away from the body is proportional to this ratio. The solution is sought for the total potential which includes both the incident and disturbed potentials, and decays towards the incident potential away from the body. A separate treatment at initial stage is used, in which the solution for the disturbed potential is sought to avoid the very large incident potential amplified by dividing the small travelled vertical distance of the wedge. The auxiliary function method is used to calculate the pressure on the body surface. Detailed results through the free surface elevation and the pressure distribution are provided to show the effect of the gravity and the wave, and their physical implications are discussed.
The Drosophila wing was proposed to be a taste organ more than 35 years ago, but there has been remarkably little study of its role in chemoreception. We carry out a differential RNA-seq analysis of ...a row of sensilla on the anterior wing margin and find expression of many genes associated with pheromone and chemical perception. To ask whether these sensilla might receive pheromonal input, we devised a dye-transfer paradigm and found that large, hydrophobic molecules comparable to pheromones can be transferred from one fly to the wing margin of another. One gene, Ionotropic receptor (IR)52a, is coexpressed in neurons of these sensilla with fruitless, a marker of sexual circuitry; IR52a is also expressed in legs. Mutation of IR52a and optogenetic silencing of IR52a+ neurons decrease levels of male sexual behavior. Optogenetic activation of IR52a+ neurons induces males to show courtship toward other males and, remarkably, toward females of another species. Surprisingly, IR52a is also required in females for normal sexual behavior. Optogenetic activation of IR52a+ neurons in mated females induces copulation, which normally occurs at very low levels. Unlike other chemoreceptors that act in males to inhibit male-male interactions and promote male-female interactions, IR52a acts in both males and females, and can promote male-male as well as male-female interactions. Moreover, IR52a+ neurons can override the circuitry that normally suppresses sexual behavior toward unproductive targets. Circuit mapping and Ca2+ imaging using the trans-Tango system reveals second-order projections of IR52a+ neurons in the subesophageal zone (SEZ), some of which are sexually dimorphic. Optogenetic activation of IR52a+ neurons in the wing activates second-order projections in the SEZ. Taken together, this study provides a molecular description of the chemosensory sensilla of a greatly understudied taste organ and defines a gene that regulates the sexual circuitry of the fly.
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