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High layer thicknesses for laser powder bed fusion are promising for productivity increase. However, these are associated with increased process instability, spatter generation and powder degradation, crucial for alloys sensitive to oxygen. The effect of increasing layer thickness from 30 to 60 µm is studied focusing on Ti-6Al-4V spatter formation during LPBF and its characterisation, with scanning and transmission electron microscopy, combustion analysis and X-ray photoelectron spectroscopy. Results indicate that spatters are covered with a uniform Ti-Al-based oxide layer and Al-rich oxide particulates, the thickness of which is about twice that present on virgin powder. The oxygen content was about 60% higher in spatters compared to the virgin powder. The study highlights that increasing the layer thickness to 60 µm permits to reduce the total generation of spatters by ∼40%, while maintaining similar spatter characteristics and static tensile properties. Hence, this allows to increase build rate without compromising process robustness. Highlights Increased layer thickness from 30 to 60 µm resulted in ∼40% lower amount of spatter generated per build Increased layer thickness from 30 to 60 µm resulted in ∼17% higher amount of generated spatter per scanned layer Increase in bulk oxygen content by >60% was registered for spatter compared to the virgin powder in both cases The oxide layer is about twice thicker on the spatter particles compared to virgin powder [ABSTRACT FROM AUTHOR]

During laser powder bed fusion (L-PBF), the protective atmosphere, normally argon, can become trapped in cavities formed during the process. We have demonstrated this by introducing ø0.5 mm pores in the CAD file (totalling 0.5% by volume) and measuring a threefold increase in argon content, versus an identical IN718 build-job without pores. For critical applications where the material is subjected to cyclic loading, any defects can act as stress raisers and initiate cracks. The pores that were introduced drastically reduced the fatigue performance of said material. However, after Hot Isostatic Pressing (HIP), the material regained its properties as if the pores were never introduced. Still, the argon remains after HIP according to measurements as it lacks solubility and thus cannot leave the material. Worth noting is that a small quantity of argon originates from gas-atomisation of the powder and thus does not leave entirely during the remelting in L-PBF. [ABSTRACT FROM AUTHOR]

Temporal and spatial patterns in flowering phenology were assessed for eight tropical African tree species. Specifically, the frequency and seasonality of flowering at seven sites in central Africa were determined using field data, graphical analysis and circular statistics. Additionally, spatial variation in the timing of flowering across species range was investigated using herbarium data, analysing the relative influence of latitude, longitude and timing of the dry season with a Bayesian circular generalized linear model. Annual flowering was found for 20 out of the 25 populations studied. For 21 populations located at the north of the climatic hinge flowering was occurring during the dry season. The analysis of herbarium collections revealed a significant shift in the timing of flowering with latitude for E. suaveolens, and with the timing of the dry season for M. excelsa (and to a lesser extent L. alata), with the coexistence of two flowering peaks near the equator where the distribution of monthly rainfall is bimodal. For the other species, none of latitude, longitude or timing of the dry season had an effect on the timing of flowering. Our study highlights the need to identify the drivers of the flowering phenology of economically important African tree species. [ABSTRACT FROM AUTHOR]

The nuclear cap-binding complex (CBC) coordinates co-transcriptional maturation, transport, or degradation of nascent RNA polymerase II (Pol II) transcripts. CBC with its partner ARS2 forms mutually exclusive complexes with diverse "effectors" that promote either productive or destructive outcomes. Combining AlphaFold predictions with structural and biochemical validation, we show how effectors NCBP3, NELF-E, ARS2, PHAX, and ZC3H18 form competing binary complexes with CBC and how PHAX, NCBP3, ZC3H18, and other effectors compete for binding to ARS2. In ternary CBC-ARS2 complexes with PHAX, NCBP3, or ZC3H18, ARS2 is responsible for the initial effector recruitment but inhibits their direct binding to the CBC. We show that in vivo ZC3H18 binding to both CBC and ARS2 is required for nuclear RNA degradation. We propose that recruitment of PHAX to CBC-ARS2 can lead, with appropriate cues, to competitive displacement of ARS2 and ZC3H18 from the CBC, thus promoting a productive rather than a degradative RNA fate. [Display omitted] • Tryptophan-containing helices of RNA effectors NCBP3, PHAX, and ZC3H18 compete to bind to CBC • NCBP3, PHAX, and ZC3H18 compete to interact with ARS2 via their ARM motifs • After effector recruitment by ARS2, their access to CBC is blocked • ZC3H18 binding to both CBC and ARS2 is required for RNA degradation of NEXT targets in vivo RNA effectors, such as NCBP3, PHAX, and ZC3H18, competitively interact with the nuclear CBC-ARS2 complex during transcription to guide nascent transcripts for processing, export, or degradation. Dubiez et al. use biochemical and structural methods to reveal high-resolution details of effector interactions with both CBC and ARS2. [ABSTRACT FROM AUTHOR]

Rotational woodlots with N2-fixing trees may be efficient agroforestry systems, allowing farmers to alternate agricultural and wood-energy production on the same area. However, their long-term effect on soil fertility is poorly understood. The aim of this study was to investigate the influence of successive phases of Acacia auriculiformis stands growing in rotation with crops on the chemical properties of sandy and very poor tropical soils. The study was conducted 22 years after the afforestation of humid herbaceous savannah in Mampu, Democratic Republic of Congo. The chemical properties of top soil (0–20 cm) from control savannah plots were compared with those from acacia plots that had undergone one, two or three rotations of acacia during the 22 year period. We found that the soil properties under non-harvested acacia stands in a 1st rotation and under acacia stands in a 2nd or 3rd rotation following charcoal production and maize and cassava cultivation were similar. Soils under all acacia stands had higher C, N and NO 3 - –N contents, but were more acidic, and had lower contents of exchangeable Ca, Mg, K and Na than the control savannah soils. Despite the increase in soil C and N, the sustainability of the acacia rotational agroforestry system after 22 years of practice is in question due to the steady decrease of soil cations, soil acidification and the risk of a decline in tree and crop productivity. To improve the nutrient balance and the sustainability of this system, different practices are recommended such as the debarking of tree stems before carbonization, the restitution of small branches and charcoal residues to the soil, and the supply of natural rock phosphate. [ABSTRACT FROM AUTHOR]

Aims: To compare respiratory status in dairy farmers with that of non-farming controls. Methods: Longitudinal study in the Doubs (France). From a cohort constituted in 1994 (T1), 215 (81.1%) dairy farmers and 110 (73.8%) controls were reevaluated in 1999 (T2). The protocol comprised a medical and occupational questionnaire, spirometric tests at both evaluations, allergological tests at T1, and a noninvasive measure of blood oxygen saturation (Spo[sub2]) at T2. Results: In 1999 analyses, the prevalence of chronic bronchitis was higher (p = 0.013), and FEV[sub1]/VC (p < 0.025) and Spo[sub2] (-0.7%, p < 0.01) lower in dairy farmers than in controls. In a multiple linear regression model, farming, age, and smoking were significantly and inversely correlated with Spo[sub2]. In the whole population, the mean annual decline in FEV[sub1] and FEV[sub1]/VC was -13.4 ml and -0.30%, respectively. Farming was associated with an accelerated decline in FEV[sub1]/VC (p < 0.025) after adjustment for covariates. No relation between allergy and respiratory function changes was observed, except for FEF[sub25-75]. Conclusions: This prospective study shows that dairy farming is associated with an excess of chronic bronchitis, with a moderate degree of bronchial obstruction and a mild decrease in Spo[sub2]. [ABSTRACT FROM AUTHOR]

Objective: To assess the lung cancer patient's prognosis in the intensive care unit with early predictive factors of death.Design: Retrospective study from July 1986 to February 1996.Setting: Medical intensive care unit at a university hospital.Patients: Fifty-seven patients with primary lung cancer admitted to our medical intensive care unit (MICU).Measurements and Results: Data collection included demographic data (age, sex, underlying diseases, MICU admitting diagnosis) and evaluation of tumor (pathologic subtypes, metastases, lung cancer staging, treatment options). Three indexes were calculated for each patient: Karnofsky performance status, Simplified Acute Physiology Score (SAPS) II, and multisystem organ failure score (ODIN score). Mortality was high in the MICU: 66% of patients died during their MICU stay, and hospital mortality reached 75%. In multivariate analysis, acute pulmonary disease and Karnofsky performance status < 70 were associated with a poor MICU and post-MICU prognosis. For the survivors, long-term survival after MICU discharge depended exclusively on the severity of the lung cancer.Conclusions: We confirmed the high mortality rate of lung cancer patients admitted to the MICU. Two predictive factors of death in MICU were identified: performance status < 70 and acute pulmonary disease. [ABSTRACT FROM AUTHOR]

The detrimental effect of nitrogen and oxygen when it comes to the precipitation of the strengthening γ" and γ' phases in Alloy 718 is well-known from traditional manufacturing. Hence, the influence of the two processing atmospheres, namely argon and nitrogen, during the laser powder bed fusion (L-PBF) of Alloy 718 parts was studied. Regardless of the gas type, considerable losses of both oxygen of about 150 ppm O2 (≈30%) and nitrogen on the level of around 400 ppm N2 (≈25%) were measured in comparison to the feedstock powder. The utilization of nitrogen as processing atmosphere led to a slightly higher nitrogen content in the as-built material—about 50 ppm—compared to the argon atmosphere. The presence of the stable nitrides and Al-rich oxides observed in the as-built material was related to the transfer of these inclusions from the nitrogen atomized powder feedstock to the components. This was confirmed by dedicated analysis of the powder feedstock and supported by thermodynamic and kinetic calculations. Rapid cooling rates were held responsible for the limited nitrogen pick-up. Oxide dissociation during laser–powder interaction, metal vaporization followed by oxidation and spatter generation, and their removal by processing atmosphere are the factors describing an important oxygen loss during L-PBF. In addition, the reduction of the oxygen level in the process atmosphere from 500 to 50 ppm resulted in the reduction in the oxygen level in as-built component by about 5%. [ABSTRACT FROM AUTHOR]

Background: A previous study showed there to be fewer microorganisms (especially thermophilic actinomycetes) on farms with artificial barn drying of fodder than on those using traditional storage methods. A cross sectional study was performed to see whether barn drying provides protection against respiratory problems in dairy farmers.Methods: The respiratory symptoms and function of a group of 123 farmers with daily exposure to cattle foddering from farms which had had a barn drying system for at least three years were compared with those of a representative sample of 274 farmers working in farms with traditional storage in five districts in the Doubs region of France.Results: Both groups were comparable for mean age, weight, height, smoking habits, alcohol consumption, past history of respiratory disease, history of allergy, geographical location of the farm, and length of exposure. Retrospectively estimated exposure to fodder was greater in the group using a barn drying system than in the group working with traditional storage. Acute symptoms at exposure (rhinitis, eye irritation, dry cough, asthma symptoms) and chronic symptoms all tended to be less frequent in the barn drying group, although not individually significantly so. Mean (SD) respiratory function parameters were higher in the barn drying group than in the traditional group: % vital capacity (VC) 104 (14) v 102 (15); % forced expiratory volume in one second (FEV1) 99 (14) v 94 (18); % FEV1/VC 96 (11) v 92 (16); % forced mid expiratory flow (FEF25-75) 87 (24) v 79 (25).Conclusion: The results of this cross sectional study suggest that barn drying of fodder may protect respiratory function in dairy farmers. [ABSTRACT FROM AUTHOR]

Airborne contamination by thermophilic actinomycetes, micromycetes and Gram negative bacteria was determined on 34 dairy farms and related to fodder drying and storage methods. Eighteen farms had a barn drying system, eight with additional heating; the remaining 16 had traditional fodder storage methods. Three air samples were obtained for each farm with a six stage Andersen sampler. The thermophilic actinomycetes were identified as Streptomyces and the dominant micromycetes as Aspergillus spp; there was no relation between the levels of these organisms. There were fewer thermophilic actinomycete colonies per Petri dish (stage 5 on the Anderson sampler) on farms with barn drying than on those with traditional storage (median (range) 7 (0-2628) and 56 (4-2628) respectively). The three farms where no thermophilic actinomycetes were found had barn drying with heating and the four most modern farms had lower thermophilic actinomycete colony counts than the others (median (range) 3 (0-10) and 48 (0-2628)). The level of thermophilic actinomycetes and, to a lesser degree, of micromycetes was higher where the farmer had farmer's lung. Thermophilic actinomycetes of the genus Streptomyces are probably the antigens associated with farmer's lung in the Doubs, and modern farms with barn drying and heating furnish some protection against this disease. [ABSTRACT FROM PUBLISHER]

The prevalence of farmer's lung was studied in five districts of the French Doubs province (Rougemont, Clerval, Levier, Montbenoît, Mouthe) on the basis of a medical and occupational questionnaire and serological studies for precipitins. Of the 1763 active farmers (response rate 69%) who participated in the study, 270 were suspected of having farmer's lung and divided, on the basis of clinical and serological criteria, into probable and possible farmer's lung groups. This subgroup of 270 patients was examined in more detail with physical examination, chest radiographs, and pulmonary function tests. Probable farmer's lung was diagnosed in 77 cases (53 men and 24 women, mean age 51.7 years), a prevalence of 43.7/1000. Possible farmer's lung was present in a further 193 subjects. Fever was the most specific symptom. In the group with probable farmer's lung the frequency of crepitations, restrictive ventilatory defect, and radiological interstitial abnormalities was 21.5%, 9.5%, and 9.2% at the time of the study. Farmer's lung was more common in the middle tablelands than in the plain or mountain areas (p less than 0.01). The difference in prevalence of farmer's lung between the Mouthe mountain and Levier middle tableland districts (25.2/1000 and 60.8/1000) raises the possibility that cold may protect against the disease. Farmer's lung was more frequent in men and in the age group 51-55 years. Among possible occupational factors, only regular work connected with feeding animals was associated with a significant risk (odds ratio 2.55 with a 95% confidence interval of 1.09-5.93). The frequency of chronic bronchitis in the population studied was 14.8%. There was a close link between farmer's lung and chronic bronchitis, 50.6% of patients with probable farmer's lung having it but only 8.6% of patients without farmer's lung (p less than 0.001). In patients with probable farmer's lung chronic bronchitis was independent of smoking and age. There were fewer smokers in the probable farmer's lung than in the non-farmer's lung group (p less than 0.05). [ABSTRACT FROM AUTHOR]

In a French region where farmer's lung (FL) is common, we determined the prevalence of FL precipitins in dairy farmers and analyzed the relation between the presence of FL precipitins and the clinical probability of the disease. All the exposed dairy farmers of both sexes (n = 2555) from five districts of the Doubs department were asked to respond to a medical and professional questionnaire. A total of 1763 (69%) farmers agreed to participate. Precipitins tests were conducted in 551 (31%) farmers who showed any respiratory symptom and in a random sample of 100 asymptomatic farmers. Serum for each farmer was analyzed by both double diffusion and immunoelectrophoresis again Micropolyspora faeni (MF) and extracts of moldy hay (HE) from Doubs. The 651 farmers were then divided into four groups (G 1-4) with a decreasing probability of FL (G1: typical FL symptoms; G4: asymptomatic farmers). The estimated prevalence of precipitins in the whole population was as follows: 1) by double diffusion, against HE: 83%, against MF: 27%;2) by immunoelectrophoresis, against HE: 26%, against MF: 19%. There was a close "linear" relation between the prevalence of precipitins detected by immunoelectrophoresis against HE and the symptoms: 51% in G1, 36% in G2, 29% in G3, and 13% in G4. Precipitins detected by immunoelectrophoresis were also related to exposure and geography (more immunization in tableland area than in plain or mountain area). Presence of precipitins detected by double diffusion was not related to exposure and geography (more immunization in tableland area than in plain or mountain area). Presence of precipitins detected by double diffusion was not related to symptoms, exposure, or geography. This study shows that the prevalence of precipitins is high in the exposed dairy farmers of Doubs, and suggests that immunoelectrophoresis (with the antigens used) is a more effective method for the diagnosis of FL than double diffusion. [ABSTRACT FROM AUTHOR]

Understanding molecular mechanisms of ribosomal translation sheds light on the emergence and evolution of protein synthesis in the three domains of life. Universally, ribosomal translation is described in three steps: initiation, elongation and termination. During initiation, a macromolecular complex assembled around the small ribosomal subunit selects the start codon on the mRNA and defines the open reading frame. In this review, we focus on the comparison of start codon selection mechanisms in eukaryotes and archaea. Eukaryotic translation initiation is a very complicated process, involving many initiation factors. The most widespread mechanism for the discovery of the start codon is the scanning of the mRNA by a pre-initiation complex until the first AUG codon in a correct context is found. In archaea, long-range scanning does not occur because of the presence of Shine-Dalgarno (SD) sequences or of short 5′ untranslated regions. However, archaeal and eukaryotic translation initiations have three initiation factors in common: e/aIF1, e/aIF1A and e/aIF2 are directly involved in the selection of the start codon. Therefore, the idea that these archaeal and eukaryotic factors fulfill similar functions within a common structural ribosomal core complex has emerged. A divergence between eukaryotic and archaeal factors allowed for the adaptation to the long-range scanning process versus the SD mediated prepositioning of the ribosome. [ABSTRACT FROM AUTHOR]