Nitrogen dynamics in soils fertilized with digestate and mineral fertilizers: A full field approach

Highly stabilized digestate from sewage sludge and digestate-derived ammonium sulphate (RFs), were used in a comparison with synthetic mineral fertilizers (SF) to crop maize in a three-year plot trial in open fields. RFs and SF were dosed to ensure the same amount of mineral N (ammonia-N). In doing so, plots fertilized with digestate received much more N (+185 kg ha^-1 of organic N) because digestate also contained organic N. The fate of nitrogen was studied by measuring mineral and organic N in soil at different depths, ammonia and N₂O emissions, and N uptake in crops. Soil analyses indicated that at one-meter depth there was no significant difference in nitrate content between RF, SF and Unfertilized plots during crop season indicating that more N dosed with digestate did not lead to extra nitrate leaching. Ammonia emissions and N content in plants and grains measured were also similar for both RF and SF. Measuring denitrification activity by using gene makers resulted in a higher denitrification activity for RF than SF. Nevertheless, N₂O measurements showed that SF emitted more N₂O than RF (although it was not statistically different) (7.59 ± 3.2 kgN ha^-1 for RF and 10.3 ± 6.8 kgN ha^-1 for SF), suggesting that probably the addition of organic matter with digestate to RF, increased the denitrification efficiency so that N₂ production was favoured. Soil analyses, although were not able detecting N differences between SF and Rf after three years of cropping, revealed a statistical increasing of total carbon, suggesting that dosing digestate lead to carbon (and maybe N) accumulation in soil. Data seem to suggest that N₂O/N₂ emission and organic N accumulation in soil can explain the fate of the extra N dosed (organic-N) in RF plots.

Using highly stabilized digestate and digestate-derived ammonium sulphate to replace synthetic fertilizers: The effects on soil, environment, and crop production

Recovered fertilizers (a highly stabilized digestate and ammonium sulphate) obtained from anaerobic digestion of sewage sludge, were used on plot trials with a maize crop, in a comparison with synthetic fertilizers. After three consecutive cropping seasons, the soils fertilized with the recovered fertilizers (RF), compared to those fertilized with synthetic fertilizers (SF), did not show significant differences either in their chemical characteristics or in the accumulation of inorganic and organic pollutants (POPs). The RF ensured an ammonia N availability in the soil equal to that of the soil fertilized with SF, during the whole period of the experiment. Furthermore, no risks of N leaching were detected, and the use of RF did not result in a greater emission of ammonia or greenhouse gases than the use of SF. The agronomic results obtained using RF were equivalent to those obtained with SF (fertilizer use efficiency of 85.3 ± 10 and 93.6 ± 4.4% for RF and SF respectively). The data show that utilising a very stable digestate can be a good strategy to produce a bio-based fertilizer with similar performance to that of a synthetic fertilizer, without environmental risks.

Environmental Performance in the Production and Use of Recovered Fertilizers from Organic Wastes Treated by Anaerobic Digestion vs Synthetic Mineral Fertilizers

Recovered fertilizers (RFs), in the form of digestate and digestate-derived ammonium sulfate, were produced from organic wastes by thermophilic anaerobic digestion (AD) at full scale. RFs were then used for crop production (maize), substituting synthetic mineral fertilizers (SFs). Environmental impacts due to both RF and SF production and use were studied by a life cycle assessment (LCA) approach using, as much as possible, data directly measured at full scale. The functional unit chosen was referred to as the fertilization of 1 ha of maize, as this paper intends to investigate the impacts of the use of RF (Scenario RF) for crop fertilization compared to that of SF (Scenario SF). Scenario RF showed better environmental performances than the system encompassing the production and use of urea and synthetic fertilizers (Scenario SF). In particular, for the Scenario RF, 11 of the 18 categories showed a lower impact than the Scenario SF, and 3 of the categories (ionizing radiation, fossil resource scarcity, and water consumption) showed net negative impacts in Scenario RF, getting the benefits from the credit for renewable energy production by AD. The LCA approach also allowed proposing precautions able to reduce further fertilizer impacts, resulting in total negative impacts in using RF for crop production. Anaerobic digestion represents the key to propose a sustainable approach in producing renewable fertilizers, thanks to both energy production and the modification that occurs to waste during a biological process, leaving a substrate (digestate) with high amending and fertilizing properties.

Measuring ammonia and odours emissions during full field digestate use in agriculture

The use of digestate in agriculture represents an opportunity for reducing the use of synthetic fertilizers while promoting nutrient and organic matter recycling, i.e. contributing to a circular economy. However, some environmental impacts could result from digestate use, with particular reference to N emissions, which can contribute to particulate matter formation in the atmosphere. So, correct digestate spreading methods need to be tested to reduce ammonia emission and, possibly, also to avoid annoyance to the inhabitants. In this work a digestate from organic wastes was used as a fertilizer by its injection at 15 cm, in comparison with a synthetic one (urea) for three consecutive years in open fields, measuring ammonia and odours emission. On average, the ammonia emission from digestate was of 25.6 ± 9.4 kg N Ha^-1 (11.6% ± 4 of Total Ammonia Nitrogen - TAN - dosed), while urea emitted 24.8 ± 8.3 kg N Ha^-1 (13.4% ± 4.5 of TAN dosed). The injected digestate also emitted less odour than urea (601 ± 531 and 1767 ± 2221 OU m^-2 h^-1, respectively), being ammonia coming from urea hydrolysis responsible for odour productions. The different N fertilizers did not lead to differences in crop yields, i.e. 18.5 ± 2.9 Mg grain Ha^-1 and 17.4 ± 1.2 Mg grain Ha^-1 for digestate and urea respectively.

Microbial recycling cells (MRCs): A new platform of microbial electrochemical technologies based on biocompatible materials, aimed at cycling carbon and nutrients in agro-food systems

This article reviews the mechanisms that drive nutrients and carbon sequestration from wastewaters by microbial electrochemical technologies (METs). In this framework, a new generation of METs is also presented (to be called microbial recycling cells, MRCs), based on 100%-recyclable materials (biomass-derived char coal, clay, terracotta, paper, ligno-cellulosic plant materials, etc.), which can act as bio-electrodes, separators and structural frames. In traditional METs architectures (based on technological materials such as carbon cloths, plastic panels, membranes, binders), inorganic salts precipitation and adsorption, as well as biofouling due to organic-matter deposition, are considered as main drawbacks that clog and hinder the systems over relatively short periods. In MRCs, these mechanisms should be maximized, instead of being avoided. In this perspective, both inorganic and organic forms of the main nutrients are sequestered from wastewater and deposited on METs modules. Once the systems become saturated, they can entirely be recycled as agricultural soil conditioners or as base for organic-mineral fertilizers.

3D early embryogenesis image filtering by nonlinear partial differential equations

We present nonlinear diffusion equations, numerical schemes to solve them and their application for filtering 3D images obtained from laser scanning microscopy (LSM) of living zebrafish embryos, with a goal to identify the optimal filtering method and its parameters. In the large scale applications dealing with analysis of 3D+time embryogenesis images, an important objective is a correct detection of the number and position of cell nuclei yielding the spatio-temporal cell lineage tree of embryogenesis. The filtering is the first and necessary step of the image analysis chain and must lead to correct results, removing the noise, sharpening the nuclei edges and correcting the acquisition errors related to spuriously connected subregions. In this paper we study such properties for the regularized Perona-Malik model and for the generalized mean curvature flow equations in the level-set formulation. A comparison with other nonlinear diffusion filters, like tensor anisotropic diffusion and Beltrami flow, is also included. All numerical schemes are based on the same discretization principles, i.e. finite volume method in space and semi-implicit scheme in time, for solving nonlinear partial differential equations. These numerical schemes are unconditionally stable, fast and naturally parallelizable. The filtering results are evaluated and compared first using the Mean Hausdorff distance between a gold standard and different isosurfaces of original and filtered data. Then, the number of isosurface connected components in a region of interest (ROI) detected in original and after the filtering is compared with the corresponding correct number of nuclei in the gold standard. Such analysis proves the robustness and reliability of the edge preserving nonlinear diffusion filtering for this type of data and lead to finding the optimal filtering parameters for the studied models and numerical schemes. Further comparisons consist in ability of splitting the very close objects which are artificially connected due to acquisition error intrinsically linked to physics of LSM. In all studied aspects it turned out that the nonlinear diffusion filter which is called geodesic mean curvature flow (GMCF) has the best performance.

Stroke rehabilitation pathways and procedures in Italy

AIM

Rehabilitation pathways and procedures after first stroke vary widely. We wanted to determine in what ways first stroke rehabilitation in Italian rehabilitation centers are similar and in line with the Italian Ministry of Health guidelines and international reports.

METHODS

Data from the study, Cerebral Ictus and Rehabilitation: Clinical Indicators and Outcomes, of the Italian Cooperative Research (ICR(2)), on 997 inpatients in 18 rehabilitation centers were analyzed and the rehabilitation procedures were compared. To do this, we compared the variables: onset admission interval, length of stay, intensity of treatment and discharge destination. Statistical analyses were performed using the Kruskal-Wallis test, the post hoc Mann-Whitney U test and the chi squared test.

RESULTS

Major differences among the centers were found for onset of admission, length of stay, intensity of treatment and discharge destination, whereas the clinical characteristics and the functional outcomes of the study population were similar.

CONCLUSIONS

Our results emphasize the importance of better integration between the acute treatment phase and the rehabilitation teams in reducing the onset admission interval of first acute stroke patients. To define optimal intensity of treatment and length of stay, randomized multicenter studies will be needed.

Complications of internal jugular vein retrograde catheterization

We report on the incidence of complications of 172 internal jugular vein retrograde catheterizations (IJVRCs) performed on 126 patients. Standard cannulation and X-ray control of the catheter tip placement were performed. Difficulties encountered during the manouvre were registered. Patients with a jugular catheter in place for more than one day had neck echography on catheter removal and one week later. Carotid artery puncture occurred in 20 (12%) cases and lymphatic vessel puncture in one. In 13 (8%) cases IJVRC failed due to difficulties in advancing the guide. X-ray films documented catheter misplacement in 39 (23%) cases: loop into the internal jugular vein in 11 (6%); paravertebral venous plexus cannulated in one; other extracranial jugular afferent cannulated in 4 (2%); catheter tip into the jugular lumen in 10 (6%); catheter tip beyond the jugular bulb in 13 (8%). First neck echography documented: one perivascular hematoma (absent one week later); 3 (4%) jugular vein thrombosis (2 asymptomatic and absent one week later; one symptomatic and still evident one week later). Positive neck echography was not associated with difficulties, length of catheterization, diameter of the catheter. IJVRC is a simple and safe procedure with a low incidence of serious complications.

The utility and cost-effectiveness of D-dimer measurements in the diagnosis of deep vein thrombosis

BACKGROUND AND OBJECTIVE

The potential utility of D-dimer measurements for the diagnosis of deep vein thrombosis became evident soon after the development of reliable commercial assays. The purpose of this review is to outline some critical aspects affecting cost-effectiveness of D-dimer measurements in the diagnosis of deep vein thrombosis (DVT).

METHODS

The authors have been working in this field contributing original papers whose data have been used for this study. In addition, the material analyzed in this article includes papers published in the journals covered by the Science Citation Index and Medline.

RESULTS

D-dimer levels are very sensitive to the process of fibrin formation/dissolution occurring with ongoing thrombosis. However, they may not be highly specific for venous thromboembolism as they are influenced by the presence of comorbid conditions potentially elevating plasma D-dimer (cancer, surgery, infectious diseases). In addition, commercially available ELISA assays, although quantitative and reproducible, cannot be used under emergency conditions because they are time-consuming and suited for batch-processing of plasma samples. Recently, new assays have been introduced which permit fast and quantitative D-dimer estimations in individual patients. We have evaluated the utility of two new rapid assays (LPIA D-dimer. Mitsubishi, and VIDAS D-DIMER, bio-Merieux) in combination with compression real-time-B-mode ultrasonography for the detection of deep vein thrombosis in asymptomatic patients following elective hip replacement and in patients with clinically suspected deep vein thrombosis. In both settings, we identified cut-off values with optimal sensitivity which allow exclusion of deep vein thrombosis in a considerable percentage of patients, with substantial sparing of economic resources. In fact, based on a cost-effectiveness analysis, a diagnostic algorithm combining D-dimers measurement and compression ultrasonography would result in cost-savings ranging from 5% to 55% in patients with high or low clinical pretest probability respectively. However, the specificity of D-dimer measurements for deep vein thrombosis was much higher in symptomatic than in asymptomatic patients. Choice of the cut-off value proved to be dependent on the method as well as on the patient populations studied.

CONCLUSIONS

The cost-effectiveness of D-dimers measurement in the diagnosis of asymptomatic DVT remains questionable. Conversely, our data strongly support the utility of D-dimers determinations in the diagnosis of symptomatic DVT. In terms of sparing economic resources, the introduction in the clinical laboratory of the rapid quantitative assays would be highly convenient, because they avoid a source of bias in the interpretation of D-dimers results, are easy to perform and do not require dedicated personnel or instrumentation. Prospective management studies validating the utility of D-dimer measurement in the diagnosis of deep vein thrombosis are urgently needed.

[Unusual case of reappearing biliary ileus in a cholecystectomized patient with late stenosis of ileo-ileal anastomosis]

An unusual case of alternating jejunal obstruction, caused by a former latero-lateral anastomosis stenosis, complicated by two stones into the afferent jejunal tract bottom, is described. The anamnestic data of previous cholecystectomy and operative finding of no one biliary fistula clue, make the authors doubtful about a hypothetic calculi migration: it is likely calculi are formed into the bowel.

[Predictive value of ultrasonography in the study of aortic abdominal aneurysms]

Several authors have collected a great deal of data in the study of abdominal aorta aneurysm through the swift diffusion of ultrasonography in the abdominal diagnostics. The authors illustrate their experience confirming the excellent reliability of ultrasonography in the diagnosis of abdominal aorta aneurysms with respect to other methods of imaging (Angiography, CAT, etc) not with a view to replacing them but as a useful means of screening.

[Invaginating colonic lipoma as a cause of intestinal occlusion]

The authors describe three cases of single invaginating colon lipoma, causing ileus. They review the literature and make some remarks.

[Use of the computer in total parenteral nutrition. Our experience]

The Authors show their method to set up and to plan a T.P.N. for surgical patients. They emphasize how the introduction of the computer in the intensive therapy practice, not only helps the work of the medical corps and the hospital attendants, but it marks and plans again every day the components' dosages on the blood-metabolical alterations, daily checked on the patients. They are here showing their experiences since 1977, appraising in a critical way the directions and the results.

[Lead arsenate as an underestimated cause of polyneuropathy in rural environment: description of two cases]

Two cases of lead arsenate polyneuropathy are described in two farmers from the same rural area; the etiology of the neurologic al disorder was ascertained only after repeated hospital admissions. It was a neuropathy of the radial nerve associated with signs of peripheral impairment of the lower limbs with pains and paresthesias. Abdominal colies, arterial hipertension, anaemia and signs of renal impairment were also present. Specific therapy was undertaken which was soon followed by nearly full recovery. Lead and arsenic toxicology are discussed with particular focusing on the necessity emphasis on commun occupational hazards both in terms of diagnostic and therapeutic procedures. The differential diagnosis is considered between the observed clinical picture and other polyneuropathies of different etiology i.e. dysmetabolic (porphyria) or toxic (insecticides, T.O.C.P., etc).

[Gastric acid secretion in the rat following end-to-side porto-caval and mesenteric-caval anastomosis]

Marked gastric acid hypersecretion by comparison with a control group was noted following the collection of samples 2 hr after ligation of the pylorus in rats 20 days after subjection to total portosystemic deviation or deviation of the mesenteric flow only into the vena cava.

[Free aminoacids and cerebral lipids in the rat following porto-cava anastomosis]

Free aminoacids and cerebral lipids were studied in rats following porto-cava anastomosis with total deviation of the portal flow. No difference in lipid pattern with respect to the controls was noted after 1 month. Changes in free aminoacids, however, were observed, including a significant increase in gamma-aminobutyric acid (GABA) and a significant decrease in glutamic acid. The meaning of these results with respect to the pathogenesis of porto-cava encephalopathy is discussed.

[Encephalopathy in the rat following partial portosystemic anastomosis]

Gamma-aminobutyric acid (GABA) values were determined in 4 groups of Sprague-Dawley rats 45-50 days after end-to-side porto-cava (PC), mesentericosplenic-cava (MSC) and mesenteric-cava (MC) anastomosis, and a false operation (FO) respectively. Values were significantly increased in the anastomosed animals. If, as may be supposed, this finding points to altered cerebral metabolism, its observation in the MSC and MC groups militates against the general view that encephalopathy in the experimental animal only occurs as a result of total deviation of the portal flow.