Effect of manure co-digestion on methane production, carbon retention, and fertilizer value of digestate

Anaerobic digestion can provide benefits not only from the perspective of renewable energy production but also in the form of fertilization effect and increased retention of C in soils after digestate application. This study consisted of two phases, where the first phase assessed the suitability of carbon-rich co-feedstocks for methane production via laboratory testing. The second phase assessed the balance and stability of C before and after anaerobic digestion by systematic digestate characterization, and by evaluating its carbon retention potential using a modeling approach. The results indicated that pyrolysis chars had a negligible effect on the methane production potential of cattle manure, while wheat straw expectedly increased methane production. Thus, a mixture of cattle manure and wheat straw was digested in pilot-scale leach-bed reactors and compared with undigested manure and straw. Although the total amount of C in the digestate was lower than in the untreated feedstocks, the digestion process stabilized C and was modeled to be more effective in retaining C in the soil than untreated cattle manure and wheat straw. In addition, digestion converted 23-27 % of the C into valuable methane, increasing the valorization of the total C in the feedstock. Considering anaerobic digestion processes as a strategy to optimize both carbon and nutrient valorization provides a more holistic approach to addressing climate change and improving soil health.

Posterior approach, fracture diagnosis, and American Society of Anesthesiology class III-IV are associated with increased risk of revision for dislocation after total hip arthroplasty: An analysis of 33,337 operations from the Finnish Arthroplasty Register

Background and objective:

Dislocation is one of the most common reasons for revision surgery after primary total hip arthroplasty. Both patient related and surgical factors may influence the risk of dislocation. In this study, we evaluated risk factors for dislocation revision after total hip arthroplasty based on revised data contents of the Finnish Arthroplasty Register.

Methods:

We analyzed 33,337 primary total hip arthroplasties performed between May 2014 and January 2018 in Finland. Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals for first dislocation revision using 18 potential risk factors as covariates, such as age, sex, diagnosis, hospital volume, surgical approach, head size, body mass index, American Society of Anesthesiology class, and fixation method.

Results:

During the study period, there were 264 first-time revisions for dislocation after primary total hip arthroplasty. The hazard ratio for dislocation revision was 3.1 (confidence interval 1.7–5.5) for posterior compared to anterolateral approach, 3.0 (confidence interval 1.9–4.7) for total hip arthroplasties performed for femoral neck fracture compared to total hip arthroplasties performed for osteoarthritis, 2.0 (confidence interval 1.0–3.9) for American Society of Anesthesiology class III–IV compared to American Society of Anesthesiology class I, and 0.5 (0.4–0.7) for 36-mm femoral head size compared to 32-mm head size.

Conclusions:

Special attention should be paid to patients with fracture diagnoses and American Society of Anesthesiology class III–IV. Anterolateral approach and 36-mm femoral heads decrease dislocation revision risk and should be considered for high-risk patients.

Mid-term changes in blood metal ion levels after Articular Surface Replacement arthroplasty of the hip

AIMS

Our first aim was to determine whether there are significant changes in the level of metal ions in the blood at mid-term follow-up, in patients with an Articular Surface Replacement (ASR) arthroplasty. Secondly, we sought to identify risk factors for any increases.

PATIENTS AND METHODS

The study involved 435 patients who underwent unilateral, metal-on-metal (MoM) hip resurfacing (HRA) or total hip arthroplasty (THA). These patients all had one measurement of the level of metal ions in the blood before seven years had passed post-operatively (early evaluation) and one after seven years had passed post-operatively (mid-term evaluation). Changes in ion levels were tested using a Wilcoxon signed-rank test. We identified subgroups at the highest risk of increase using a multivariable linear logistic regression model.

RESULTS

There were significant increases in the levels of metal ions for patients who underwent both MoM HRA (Chromium (Cr): 0.5 parts per billion (ppb); Cobalt (Co): 1.1 ppb) and MoM THA (Cr: 0.5 ppb; Co: 0.7 ppb). In a multivariable model considering MoM HRAs, the change in the levels of metal ions was influenced by female gender (Co: Odds Ratio (OR) 1.42; p = 0.002 and Cr: OR 1.08; p = 0.006). The change was found to be irrespective of the initial level for the MoM HRAs, whereas there was a negative relationship between the initial level and the change in the level for those with a MoM THA (Co: OR -0.43; p < 0.001 and Cr: OR -0.14; p = 0.033).

CONCLUSION

The levels of metal ions in the blood increase significantly over the period until mid-term follow-up in patients with both a MoM HRA and those with a MoM THA. We recommend that the levels of metal ions be measured most frequently for women with a MoM HRA. While those with a MoM THA appear to stabilise at a certain level, the accuracy of this trend is not yet clear. Vigilant follow-up is still recommended. Cite this article: Bone Joint J 2017;99-B(4 Supple B):33-40.

Childhood socioeconomic status modifies the association between intellectual abilities at age 20 and mortality in later life

Background

People who score poorly in intellectual ability tests have shorter life expectancy. A study was undertaken to determine whether this association is different in people from different socioeconomic backgrounds.

Methods

The mortality of 2786 men born in Helsinki, Finland during 1934–1944 who, as military conscripts, underwent a standardised intellectual ability test comprising verbal, visuospatial and arithmetic reasoning subtests was studied. Mortality data came from the Finnish Death Register.

Results

Comparing men in the lowest and highest test score quartiles, HRs for all-cause mortality were 1.9 (95% CI 1.4 to 2.5) for verbal reasoning, 2.2 (95% CI 1.6 to 3.0) for visuospatial reasoning and 1.9 (95% CI 1.4 to 2.5) for arithmetic reasoning, corresponding to 2.6, 3.4 and 2.6 excess years of life lost, respectively. Associations were similar for cardiovascular and non-cardiovascular mortality. Intellectual ability scores were stronger predictors in men who grew up in middle-class families. Compared with middle-class men in the highest quartile of the visuospatial reasoning score, middle-class men in the lowest quartile lost 6.5 years of life while men from families of manual workers in the highest quartile lost 2.8 years and men in the lowest quartile lost 5.6 years.

Conclusions

High intellectual ability in men aged 20 protects them from mortality in later life. This effect is stronger in men who grew up in middle-class families than in those who grew up in manual worker families. This finding suggests that early life conditions that are unfavourable to the development of cognitive abilities negate the life expectancy benefits of being born into a more affluent family.

An outbreak of gastroenteritis from a non-chlorinated community water supply

STUDY OBJECTIVE

To determine the source and the extent of a community wide outbreak of gastroenteritis.

DESIGN

A matched case-control study with postal questionnaires. Subtyping of campylobacter strains by pulsed field gel electrophoresis (PFGE).

SETTING

A rural municipality with a population of 8600 in southern Finland, August 2000. Two thirds of the population receive non-chlorinated ground water from the municipal water supply.

PARTICIPANTS

Cases were randomly selected among residents of the municipality who contacted the municipal health centre because of gastroenteritis and had illness onset between 31 July and 20 August 2000. Community controls were identified from the population registry and matched according to sex, year of birth, and postal code.

MAIN RESULTS

Four hundred and sixty three persons contacted the municipal health centre because of gastroenteritis. Campylobacter jejuni was isolated from stool samples of 24 persons. One hundred and thirty seven cases and 388 controls were enrolled in the case-control study. In multivariate analysis, drinking unboiled water from the municipal supply was significantly associated with illness (odds ratio 11.1, 95% confidence interval 1.4 to 90.2). C jejuni was isolated from one tap water sample. The water isolate and all but one of the patient isolates were indistinguishable by PFGE.

CONCLUSIONS

Combining epidemiological investigation with molecular subtyping methods provided strong evidence that water was the source of the outbreak. Non-chlorinated small ground water systems may be susceptible to waterborne outbreaks and constitute a risk to rural populations.