Little is known about the impact of changing temperature regimes on composition and diversity of cryptogam communities in the Arctic and Subarctic, despite the well‐known importance of lichens and ...bryophytes to the functioning and climate feedbacks of northern ecosystems. We investigated changes in diversity and abundance of lichens and bryophytes within long‐term (9–16 years) warming experiments and along natural climatic gradients, ranging from Swedish subarctic birch forest and subarctic/subalpine tundra to Alaskan arctic tussock tundra. In both Sweden and Alaska, lichen diversity responded negatively to experimental warming (with the exception of a birch forest) and to higher temperatures along climatic gradients. Bryophytes were less sensitive to experimental warming than lichens, but depending on the length of the gradient, bryophyte diversity decreased both with increasing temperatures and at extremely low temperatures. Among bryophytes, Sphagnum mosses were particularly resistant to experimental warming in terms of both abundance and diversity. Temperature, on both continents, was the main driver of species composition within experiments and along gradients, with the exception of the Swedish subarctic birch forest where amount of litter constituted the best explanatory variable. In a warming experiment in moist acidic tussock tundra in Alaska, temperature together with soil ammonium availability were the most important factors influencing species composition. Overall, dwarf shrub abundance (deciduous and evergreen) was positively related to warming but so were the bryophytes Sphagnum girgensohnii, Hylocomium splendens and Pleurozium schreberi; the majority of other cryptogams showed a negative relationship to warming. This unique combination of intercontinental comparison, natural gradient studies and experimental studies shows that cryptogam diversity and abundance, especially within lichens, is likely to decrease under arctic climate warming. Given the many ecosystem processes affected by cryptogams in high latitudes (e.g. carbon sequestration, N2‐fixation, trophic interactions), these changes will have important feedback consequences for ecosystem functions and climate.
Isotropic-bonded magnets were fabricated by powder bed fusion additive manufacturing (AM) using a feedstock composed of polymeric binder polyamide 12 (PA-12) and a near stoichiometric Nd 2 Fe 14 B ...atomized nanocrystalline powder. The AM equipment constructed for that purpose uses a computer-controlled laser beam to melt the binder and build the parts layer by layer. Three process parameters were evaluated: layer thickness (LT), hatch spacing (HS), and laser power (LP). For the evaluation of magnetic properties, cylindrical samples with diameter and height of 10 mm were produced and measured in a hysteresisgraph. For a feedstock, based on a 34% volumetric fraction of PA-12, the highest density value achieved was 3.6 g/cm 3 , resulting in a remanence of 0.3 T. These relatively low values for remanence are due to the isotropic characteristic of the powder, the binder fraction, and the interparticle porosity not being completely eliminated. Results indicate that LT affects densification more significantly than LP and HS. Consequently, remanence follows the same trend. Coercivity has not been affected much by optimized process parameters, since the values of original atomized powder of around 700 kA/m remained practically the same. The overall conclusion shows encouraging results to explore this alternative AM technique to produce net shape permanent magnets.
The transcriptome of endosymbiotic Bradyrhizobium japonicum bacteroids was assessed, using RNA extracted from determinate soybean root nodules. Results were compared with the transcript profiles of ...B. japonicum cells grown in either aerobic or microaerobic culture. Microoxia is a known trigger for the induction of symbiotically relevant genes. In fact, one third of the genes induced in bacteroids at day 21 after inoculation are congruent with those up-regulated in culture by a decreased oxygen concentration. The other induced genes, however, may be regulated by cues other than oxygen limitation. Both groups of genes provide a rich source for the possible discovery of novel functions related to symbiosis. Samples taken at different timepoints in nodule development have led to the distinction of genes expressed early and late in bacteroids. The experimental approach applied here is also useful for B. japonicum mutant analyses. As an example, we compared the transcriptome of wild-type bacteroids with that of bacteroids formed by a mutant defective in the RNA polymerase transcription factor σ54. This led to a collection of hitherto unrecognized B. japonicum genes potentially transcribed in planta in a σ54-dependent manner.
Arikace is a liposomal amikacin preparation for aerosol delivery with potent Pseudomonas aeruginosa killing and prolonged lung deposition.
To examine the safety and efficacy of 28 days of once-daily ...Arikace in cystic fibrosis (CF) patients chronically infected with P aeruginosa.
105 subjects were evaluated in double-blind, placebo-controlled studies. Subjects were randomised to once-daily Arikace (70, 140, 280 and 560 mg; n=7, 5, 21 and 36 subjects) or placebo (n=36) for 28 days. Primary outcomes included safety and tolerability. Secondary outcomes included lung function (forced expiratory volume at one second (FEV1)), P aeruginosa density in sputum, and the Cystic Fibrosis Quality of Life Questionnaire-Revised (CFQ-R).
The adverse event profile was similar among Arikace and placebo subjects. The relative change in FEV1 was higher in the 560 mg dose group at day 28 (p=0.033) and at day 56 (28 days post-treatment, 0.093L±0.203 vs -0.032L±0.119; p=0.003) versus placebo. Sputum P aeruginosa density decreased >1 log in the 560 mg group versus placebo (days 14, 28 and 35; p=0.021). The Respiratory Domain of the CFQ-R increased by the Minimal Clinically Important Difference (MCID) in 67% of Arikace subjects (560 mg) versus 36% of placebo (p=0.006), and correlated with FEV1 improvements at days 14, 28 and 42 (p<0.05). An open-label extension (560 mg Arikace) for 28 days followed by 56 days off over six cycles confirmed durable improvements in lung function and sputum P aeruginosa density (n=49).
Once-daily Arikace demonstrated acute tolerability, safety, biologic activity and efficacy in patients with CF with P aeruginosa infection.
Prokaryotes, due to their moderate complexity, are particularly amenable to the comprehensive identification of the protein repertoire expressed under different conditions. We applied a generic ...strategy to identify a complete expressed prokaryotic proteome, which is based on the analysis of RNA and proteins extracted from matched samples. Saturated transcriptome profiling by RNA-seq provided an endpoint estimate of the protein-coding genes expressed under two conditions which mimic the interaction of Bartonella henselae with its mammalian host. Directed shotgun proteomics experiments were carried out on four subcellular fractions. By specifically targeting proteins which are short, basic, low abundant, and membrane localized, we could eliminate their initial underrepresentation compared to the estimated endpoint. A total of 1250 proteins were identified with an estimated false discovery rate below 1%. This represents 85% of all distinct annotated proteins and ∼90% of the expressed protein-coding genes. Genes that were detected at the transcript but not protein level, were found to be highly enriched in several genomic islands. Furthermore, genes that lacked an ortholog and a functional annotation were not detected at the protein level; these may represent examples of overprediction in genome annotations. A dramatic membrane proteome reorganization was observed, including differential regulation of autotransporters, adhesins, and hemin binding proteins. Particularly noteworthy was the complete membrane proteome coverage, which included expression of all members of the VirB/D4 type IV secretion system, a key virulence factor.
•Sm2Fe17Nx bonded magnets using HDDR powders were firstly produced via LPBF;•Irregular-shaped particles present superior AD and FR than melt-spun ribbons;•XRD revealed no structural modification on ...the HDDR powders after LPBF;•A promising method of Sm2Fe17Nx powder production for LPBF applications;
Powders to be used as the main feedstock component for additive manufacturing processes, such as Laser Powder Bed Fusion (LPBF) technique, must present suitable technological properties, mainly high values of apparent density (AD) and flow rate (FR). These features are directly related to particle size, morphology, and size distribution. Although these issues have already been addressed to feedstocks based on Nd-Fe-B powders, the potential use of Sm-Fe-N powder as a raw material for feedstock processes has been scarcely explored thus far. If on one hand it is well established in the literature that Sm-Fe-N particles should be small (≈ 2 μm) to present sufficiently high values of intrinsic coercivity (Hcj, > 700 kA/m), on the other hand, however, smaller particles exhibit AD and FR values that are not appropriate for use in LPBF. An alternative to circumvent this apparently conflicting situation is to refine the microstructure of the particles in order to increase coercivity, instead of reducing particle size itself, which could be achieved via Hydrogenation-Disproportionation-Desorption-Recombination (HDDR). Considering this context, the main objective of this work is to study the feasibility of using Sm2Fe17Nx-based powders produced via the HDDR process followed by nitrogenation to obtain as-printed bonded magnets by the LPBF process. AD and FR of sieved powders with two distinct granulometry (< 45 μm and 45 < x < 63 μm) were evaluated. The obtained HDDR Sm-Fe-N powders presented values of Hcj = 683–777 kA/m, comparable to commercial nanocrystalline powders obtained by melt spinning. Powders were mixed with polyamide-12 (PA12) powder and used as feedstock to obtain bonded magnets by the LBPF technique. Microstructural properties of the as-printed bonded magnets were analyzed by Scanning Electron Microscopy (SEM). The effect of the LPBF process on the structural and magnetic properties of HDDR Sm-Fe-N powders was evaluated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). Both coarser and finer powders presented no structural modifications or reduction in magnetic property values after the laser processing. However, denser as-printed bonded magnets were obtained using the coarser one, emerging as a potential candidate to be used as feedstock in LPBF process.
The structure and properties of parts made by selective laser sintering (SLS) depend on the process parameters and the characteristics of the powder material to be processed. The use of polymeric ...blends can increase the range of structures and properties of SLS parts. This study investigates the processing of blends of polyamide (PA2200) and high-density polyethylene (HDPE) by SLS using a CO
2 laser. Powder properties of undiluted polymers, mixture composition, processing parameters and their influence on the microstructure of the specimens manufactured, were evaluated. PA2200 showed higher absorption of laser energy than HDPE during the sintering of blend specimens, with subsequent thermal energy transfer to the melting of the HDPE phase. The microstructures of PA2200/HDPE blend specimens were heterogeneous with co-continuous and disperse phases depending on the quantity of HDPE. The porosity and crystallinity also changed as a function of the component proportions. These results suggest that it is feasible to manufacture blend parts using SLS, with control over the structure and properties being achieved through selecting the polymer properties (laser absorption and melt flow), powder characteristics (form and size distribution) and the optimum process parameters according to the blend composition.
Several plant species of the genus Psychotria (Rubiaceae) harbor Burkholderia sp. bacteria within specialized leaf nodules. The bacteria are transmitted vertically between plant generations and have ...not yet been cultured outside of their host. This symbiosis is considered to be obligatory because plants devoid of symbionts fail to develop into mature individuals. The genome of 'Candidatus Burkholderia kirkii' has been sequenced recently and has revealed evidence of reductive genome evolution, as shown by the proliferation of insertion sequences and the presence of numerous pseudogenes. We employed shotgun proteomics to investigate the expression of 'Ca. B. kirkii' proteins in the leaf nodule. Drawing from this dataset and refined comparative genomics analyses, we designed a new pseudogene prediction algorithm and improved the genome annotation. We also found conclusive evidence that nodule bacteria allocate vast resources to synthesis of secondary metabolites, possibly of the C7N aminocyclitol family. Expression of a putative 2-epi-5-valiolone synthase, a key enzyme of the C7N aminocyclitol synthesis, is high in the nodule population but downregulated in bacteria residing in the shoot apex, suggesting that production of secondary metabolites is particularly important in the leaf nodule.
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•Anisotropic Nd-Fe-B bonded magnets were obtained via Laser Powder Bed Fusion.•Mechanical orientation of elongated anisotropic magnetic particles was explored.•As-printed bonded ...magnets exhibited a mean alignment degree of < cos θ> = 0.73.•Alignment degree can be tailored as a function of the size of the magnetic particles.
Nd-Fe-B bonded magnets are an important class of permanent magnets, employed in many technological sectors. Additive Manufacturing (AM) enables the fabrication of net-shape bonded magnets with complex geometries, allowing to tailor their magnetic stray field specifically for a given application. A crucial challenge is the production of magnetically anisotropic components. Approaches presented in the literature up to now required a post-printing procedure or the complex integration of a magnetic field source into the AM process. Here, we present a technique to fabricate anisotropic bonded magnets via Laser Powder Bed Fusion (LPBF) by utilizing the mechanical alignment of anisotropic particles in a single step, without the need for a magnetic field source. Anisotropic bonded magnets were fabricated using a mixture of anisotropic Nd-Fe-B powder (MQA-38–14) and polyamide-12 (PA12). This magnetic powder consists of ellipsoidal particles, where the easy magnetization axis is distributed perpendicular to their longest side, and the mean aspect ratio of 3:1 can be exploited to generate magnetic texture. Depending on the particle size used as feedstock, the degree of alignment (<cosθ>) can be tailored to a maximum of <cosθ> = 0.78. The fabricated anisotropic bonded magnets exhibited a maximum remanence of Jr = 377 mT and an energy product of (BH)max = 28.6 kJ/m3, respectively.
By use of a transient replication assay, nine genes involved in DNA replication were identified in the genome of the Autographa californica baculovirus. Six genes encoding helicase, DNA polymerase, ...IE-1, LEF-1, LEF-2, and LEF-3 are essential for DNA replication while three genes encoding P35, IE-2, and PE38 stimulate DNA replication. No stimulation by the AcMNPV pcna gene, encoding a protein with sequence homology to proliferating-cell nuclear antigen, was observed. A pattern of amino acids found in a number of single-stranded-DNA-binding proteins was identified in the carboxyl-terminal region of IE-1.
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