Water productivity of contrasting rice genotypes grown under water-saving conditions in the tropics and investigation of morphological traits for adaptation

Alternate wetting and drying (AWD) irrigation in lowland rice has been successfully implemented in farmers' fields to reduce water input, and thereby increasing water productivity. Reported effects on grain yield were, however, contradictory: yield was reduced, maintained, or even increased when compared with continuously flooded (CF) conditions. This study was conducted in heavy clay soil to investigate yield variation among a range of genotypes grown under AWD and to determine some aboveground traits related to crop adaptation. The effect of AWD on grain yield, with a critical threshold of soil water potential for irrigation fixed at -30 kPa, varied among the 10 genotypes evaluated. Two adapted genotypes were identified with similar grain yield under CF and AWD in both experimental seasons. The grain yield of the aerobic-adapted cultivar included in the study was also maintained under AWD, however, its yield was comparatively low. The reduction in grain yield of the non-adapted genotypes ranged from 9 to 13% in the 2006 dry season and from 6 to 17% in the 2008 dry season. None of the yield components could explain by itself the variability in genotype response: in adapted genotypes, grain yield was maintained because of compensation from or maintenance of yield components, whereas, in non-adapted genotypes, grain yield reduction was not due to the decrease of one component only. Modified biomass partitioning appeared as a main driver for adaptation to AWD: adapted genotypes were characterized by larger sink size at flowering, and weaker stems and less unfilled grain number at maturity, suggesting an increase in the sink strength of the filling spikelets. The aboveground traits identified here will be of great help to further increase water productivity under the AWD strategies set up previously by IRRI water scientists.Alternate wetting and drying Water input and water productivity Sink size Stem vigor Spikelet sink strength Yield components compensation

Usefulness of cone-beam computed tomography and automatic vessel detection software in emergency transarterial embolization

Background: This study was designed to evaluate the utility of dual phase cone beam computed tomography (DP-CBCT) and automatic vessel detection (AVD) software to guide transarterial embolization (TAE) of angiographically challenging arterial bleedings in emergency settings. Methods: Twenty patients with an arterial bleeding at computed tomography angiography and an inconclusive identification of the bleeding vessel at the initial 2D angiographic series were included. Accuracy of DP-CBCT and AVD software were defined as the ability to detect the bleeding site and the culprit arterial bleeder, respectively. Technical success was defined as the correct positioning of the microcatheter using AVD software. Clinical success was defined as the successful\ua0embolization. Total volume of iodinated contrast medium and overall procedure time were registered. Results: The bleeding site was not detected by initial angiogram in 20\ua0% of cases, while impossibility to identify the bleeding vessel was the reason for inclusion in the remaining cases. The bleeding site was detected by DP-CBCT in 19 of 20 (95\ua0%) patients; in one case CBCT-CT fusion was required. AVD software identified the culprit arterial branch in 18 of 20 (90\ua0%) cases. In two cases, vessel tracking required manual marking of the candidate arterial bleeder. Technical success was 95\ua0%. Successful embolization was achieved in all patients. Mean contrast volume injected for each patient was 77.5\ua0ml, and mean overall procedural time was 50\ua0min. Conclusions: C-arm CBCT and AVD software during TAE of angiographically challenging arterial bleedings is feasible and may facilitate successful embolization. Staff training in CBCT imaging and software manipulation is necessary

MRI-guided and CT-guided cervical nerve root infiltration therapy: a cost comparison

PURPOSE To evaluate and compare the costs of MRI-guided and CT-guided cervical nerve root infiltration for the minimally invasive treatment of radicular neck pain. MATERIALS AND METHODS Between September 2009 and April 2012, 22 patients (9 men, 13 women; mean age: 48.2 years) underwent MRI-guided (1.0 Tesla, Panorama HFO, Philips) single-site periradicular cervical nerve root infiltration with 40 mg triamcinolone acetonide. A further 64 patients (34 men, 30 women; mean age: 50.3 years) were treated under CT fluoroscopic guidance (Somatom Definition 64, Siemens). The mean overall costs were calculated as the sum of the prorated costs of equipment use (purchase, depreciation, maintenance, and energy costs), personnel costs and expenditure for disposables that were identified for MRI- and CT-guided procedures. Additionally, the cost of ultrasound guidance was calculated. RESULTS The mean intervention time was 24.9 min. (range: 12 - 36 min.) for MRI-guided infiltration and 19.7 min. (range: 5 - 54 min.) for CT-guided infiltration. The average total costs per patient were EUR 240 for MRI-guided interventions and EUR 124 for CT-guided interventions. These were (MRI/CT guidance) EUR 150/60 for equipment use, EUR 46/40 for personnel, and EUR 44/25 for disposables. The mean overall cost of ultrasound guidance was EUR 76. CONCLUSION Cervical nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. However, since it does not involve radiation exposure for patients and personnel, MRI-guided nerve root infiltration may become a promising alternative to the CT-guided procedure, especially since a further price decrease is expected for MRI devices and MR-compatible disposables. In contrast, ultrasound remains the less expensive method for nerve root infiltration guidance

A study of an improved cutting mechanism of composite materials using novel design of diamond micro-core drills

Core drilling at small diameters in carbon composite materials is largely carried out using diamond electroplated tools consisting of hollow shafts and simplistic geometries that are likely to work in an abrasional/rubbing mode for material removal. The paper reports a step change in the performance of small diameter core drilling by facilitating a shearing mechanism of the composite workpiece through the utilisation of a novel tool design. This has been achieved by laser producing core drills from solid polycrystalline diamond, incorporating controlled cutting edges where the geometries are defined. To evaluate the efficiency of the shearing vs. abrasion/rubbing cutting mechanisms, a critical comparison between the novel (defined cutting edges) and the conventional electroplated tools (randomly distributed micro-grains) has been made with reference to thrust forces, tool wear mechanisms and their influences on the hole quality (e.g. delamination, fibre pullout). This work has been augmented by studies using high-speed thermal imaging of the two tool types in operation. The examinations have shown that, based on the concept of defined cutting edges in solid diamond, there is the possibility to make significant improvements in core drilling performance, (ca. 26% lower thrust force, minimal tool surface clogging, lower drilling temperatures) resulting in improved cleanliness of fibre fracture and a reduced tendency of material delamination