Light-matter interaction at the nanoscale in magnetic alloys and heterostructures is a topic of intense research in view of potential applications in high-density magnetic recording. While the element-specific dynamics of electron spins is directly accessible to resonant x-ray pulses with femtosecond time structure, the possible element-specific atomic motion remains largely unexplored. We use ultrafast electron diffraction (UED) to probe the temporal evolution of lattice Bragg peaks of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse.
View Article and Find Full Text PDFIsland systems provide important contexts for studying processes underlying lineage migration, species diversification, and organismal extinction. The Hawaiian endemic mints (Lamiaceae family) are the second largest plant radiation on the isolated Hawaiian Islands. We generated a chromosome-scale reference genome for one Hawaiian species, Stenogyne calaminthoides, and resequenced 45 relatives, representing 34 species, to uncover the continental origins of this group and their subsequent diversification.
View Article and Find Full Text PDFKnowledge of Eurasian aspen's (Populus tremula L.) ecological and growth characteristics is of high importance to plant and wildlife community ecology, and noncommercial forest ecosystem services. This research assessed these characteristics, identified aspen's habitat optimum, and examined causality of its current scarce distribution in central Europe.
View Article and Find Full Text PDFBiodiversity world-wide has been under increasing anthropogenic pressure in the past century. The long-term response of biotic communities has been tackled primarily by focusing on species richness, community composition and functionality. Equally important are shifts between entire communities and habitat types, which remain an unexplored level of biodiversity change.
View Article and Find Full Text PDFIdentification and manipulation of cellular energy regulation mechanisms may be a strategy to increase productivity in photosynthetic organisms. This work tests the hypothesis that polyphosphate synthesis and degradation play a role in energy management by storing or dissipating energy in the form of ATP. A polyphosphate kinase () knock-out strain unable to synthesize polyphosphate was generated in the cyanobacterium sp.
View Article and Find Full Text PDFThermoelectric materials play a vital role in the pursuit of a sustainable energy system by allowing the conversion of waste heat to electric energy. Low thermal conductivity is essential to achieving high-efficiency conversion. The conductivity depends on an interplay between the phononic and electronic properties of the nonequilibrium state.
View Article and Find Full Text PDFRecent world events have led to an increased interest in developing rapid and inexpensive clinical diagnostic platforms for viral detection. Here, the development of a cell-free toehold switch-based biosensor, which does not require upstream amplification of target RNA, is described for the detection of RNA viruses. Toehold switches were designed to avoid interfering secondary structure in the viral RNA binding region, mutational hotspots, and cross-reacting sequences of other coronaviruses.
View Article and Find Full Text PDFExcess phosphorus (P) in wastewater effluent poses a serious threat to aquatic ecosystems and can spur harmful algal blooms. Revolving algal biofilm (RAB) systems are an emerging technology to recover P from wastewater before discharge into aquatic ecosystems. In RAB systems, a community of microalgae take up and store wastewater P as polyphosphate as they grow in a partially submerged revolving biofilm, which may then be harvested and dried for use as fertilizer in lieu of mined phosphate rock.
View Article and Find Full Text PDFPhotosynthetic productivity is limited by low energy conversion efficiency in naturally evolved photosynthetic organisms, via multiple mechanisms that are not fully understood. Here we show evidence that extends recent findings that cyanobacteria use "futile" cycles in the synthesis and degradation of carbon compounds to dissipate ATP. Reduction of the glycogen cycle or the sucrose cycle in the model cyanobacterium 6803 led to redirection of cellular energy toward faster growth under simulated outdoor light conditions in photobioreactors that was accompanied by higher energy charge [concentration ratio of ATP/(ATP + ADP)].
View Article and Find Full Text PDFIn contrast to silicon-based transistors, single-molecule junctions can be gated by simple mechanical means. Specifically, charge can be transferred between the junction's electrodes and its molecular bridge when the interelectrode distance is modified, leading to variations in the electronic transport properties of the junction. While this effect has been studied extensively, the influence of the molecular orientation on mechanical gating has not been addressed, despite its potential influence on the gating effectiveness.
View Article and Find Full Text PDFUngulate populations are increasing across Europe with important implications for forest plant communities. Concurrently, atmospheric nitrogen (N) deposition continues to eutrophicate forests, threatening many rare, often more nutrient-efficient, plant species. These pressures may critically interact to shape biodiversity as in grassland and tundra systems, yet any potential interactions in forests remain poorly understood.
View Article and Find Full Text PDFAlgae (including eukaryotic microalgae and cyanobacteria) have been genetically engineered to convert light and carbon dioxide to many industrially and commercially relevant chemicals including biofuels, materials, and nutritional products. At industrial scale, genetically engineered algae may be cultivated outdoors in open ponds or in closed photobioreactors. In either case, industry would need to address a potential risk of the release of the engineered algae into the natural environment, resulting in potential negative impacts to the environment.
View Article and Find Full Text PDFThe radiolytic stability of hydrophobic extracting compounds CyMe-BTBP and CyMe-BTPhen and a hydrophilic masking agent (PhSOH)-BTPhen, widely employed for trivalent minor actinoid and lanthanoid separation, against γ radiation was tested. Even though the solvent with a promising fluorinated diluent BK-1 provides better extraction properties compared to octan-1-ol, its radiation stability is much lower, and no extraction was observed already after an absorbed dose of 150 kGy (CyMe-BTBP) or 200 kGy (CyMe-BTPhen). For the (PhSOH)-BTPhen hydrophilic masking agent, the results showed that the rate of radiolytic degradation was significantly higher in 0.
View Article and Find Full Text PDFBackground: Bariatric surgery in advanced age patients (>65-years-old) has been proven safe and effective. Revisional bariatric surgery is infrequently required for cases of refractory obesity. However, there is a paucity of data regarding revisional surgery for the elderly.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2020
Twin domains are naturally present in the topological insulator Bi2Se3 and strongly affect its properties. While studies of their behavior in an otherwise ideal Bi2Se3 structure exist, little is known about their possible interaction with other defects. Extra information is needed, especially for the case of an artificial perturbation of topological insulator states by magnetic doping, which has attracted a lot of attention recently.
View Article and Find Full Text PDFRemoval of canopy trees by logging causes shifts in herbaceous diversity and increases invasibility of the forest understory. However, disturbed (cut) trees of many species do not die but resprout from remaining parts. Because sprouts develop vigorously immediately after disturbances, we hypothesized that sprouts of logged trees offset the changes in species richness and invasibility of the herbaceous layer by eliminating the rise in the resource availability during the time before regeneration from seeds develops.
View Article and Find Full Text PDFBackground: Currently, no evidence compares outcomes for techniques utilizing surgical specimen extractions bags versus unprotected extraction.
Methods: Evaluation of sleeve gastrectomies performed at two high-volume centers. Cases where an extraction bag was used (+EB) were compared to bag-less extraction (-EB).
Cyanobacterial biofuels have the potential to reduce the cost and climate impacts of biofuel production because primary carbon fixation and conversion to fuel are completed together in the cultivation of the cyanobacteria. Cyanobacterial biofuels, therefore, do not rely on costly organic carbon feedstocks that heterotrophs require, which reduces competition for agricultural resources such as arable land and freshwater. However, the published product titer achieved for most molecules of interest using cyanobacteria lag behind what has been achieved using yeast and ( cultures.
View Article and Find Full Text PDFSynechocystis sp. PCC 6803 is a model cyanobacterium which has been investigated to produce a variety of fuels and chemicals. Genetic mutations are of interest for studying photosynthesis and engineering chemical production.
View Article and Find Full Text PDFUnderstory herbs and soil invertebrates play key roles in soil formation and nutrient cycling in forests. Studies suggest that diversity in the canopy and in the understory are positively associated, but these studies often confound the effects of tree species diversity with those of tree species identity and abiotic conditions. We combined extensive field sampling with structural equation modeling to evaluate the simultaneous effects of tree diversity on the species diversity of understory herbs, beetles, and earthworms.
View Article and Find Full Text PDFThe idea of the preoperative anesthesia clinic as a means of examining and treating the patient so that he will arrive in the operating theater as strong and healthy as possible is well established in practice and literature.However, problems in clinic design and execution often result in high patient waiting times, decreased patient and staff satisfaction, decreased patient capacity, and high clinic costs. Although the details of clinic design, outcomes, and satisfaction have been extensively evaluated at civilian hospitals, we have not found corresponding literature addressing these issues specifically within military preoperative evaluation clinics.
View Article and Find Full Text PDFIntroduction: Internal hernias (IHs) occur more frequently in laparoscopic gastric bypass (LGB) surgery than in the classic open procedure. The incidence of small bowel obstruction after LGB ranges from 1.8% and 9.
View Article and Find Full Text PDFMilitary orthopaedic surgeons in deployed environments along with orthopaedic surgeons working in more austere environments often find themselves without surgical equipment that they are normally accustomed to having in the operative suite. Today's U.S.
View Article and Find Full Text PDFBackground: Humanitarian medical care is an essential task of the deployed military health care system. The purpose of this study was to analyze referral acceptance in treating injured local national patients during Operation Enduring Freedom.
Methods: A prospective observation study of local nationals who were referred for humanitarian trauma care in Afghanistan from March through August 2009.