Fluorescence microscopic investigation of PCE superplasticiser adsorption in calcined clay blended cement.

Global efforts to minimise carbon dioxide emissions are also leading to attempts to use calcined clays (CC) as a partial substitute for cement in concrete. While the hydration mechanism of such CC blended cements is now well understood, the range of effective admixtures like polycarboxylate ethers (PCE) is limited. There are PCE types that promise relatively high effectiveness, but the mechanisms of action are not yet sufficiently understood. For a detailed understanding of the adsorption of such PCEs, spatially resolved studies of the binder were performed using a combination of fluorescence and scanning electron microscopy. In a comparison of two superplasticisers, the investigations have shown different sites of preferred adsorption in a CC blended system and the results can be correlated with flow tests and setting behaviour. The investigations have shown that a certain PCE type has a higher adsorption on CC and other components of a blended system in comparison to other types.

Impacts of the COVID-19 pandemic on vegetable production systems and livelihoods: Smallholder farmer experiences in Burkina Faso.

At the onset of COVID-19, researchers quickly recognized the need for research on the consequences of the pandemic for agricultural and food systems, both in terms of immediate impacts on access to inputs and labor, disruptions in transportation and markets, and the longer-term implications on crop productivity, income, and livelihoods. Vegetable production and supply chains are particularly vulnerable due to the perishable nature of the products and labor-intensive production practices. The purpose of this study was to understand the impacts of COVID-19 on vegetable production in Burkina Faso in terms of both the biophysical aspects such as yields and access to inputs and socioeconomic aspects such as access to labor, markets, and social services. A survey was developed to better understand smallholder farmer experiences regarding the impacts of COVID-19 on their vegetable production systems and social well-being. The survey was administered (between August and October 2020) with smallholder farmers (n = 605) in 13 administrative regions covering all agroecological zones of Burkina Faso. The survey results clearly show impacts of COVID-19 on vegetable systems, including a reduction in access to inputs, a reduction in yields, a loss of income, reduced access to local and urban markets, reduced access to transportation, and an increase in post-harvest loss. Market access, distribution, and disruptions were a major shock to the system. Results also showed an increase in women's labor in the household, and for youth, an increase in unemployment, job loss, and concerns of poverty. Finally, food security and social supports were highlighted as major issues for resilience and livelihoods. The results from this survey should be helpful to policymakers and researchers to develop policies and strategies to minimize the negative impacts of this ongoing pandemic on the agri-food systems and support smallholder farmers to overcome stress caused by COVID-19.

Smallholder farmer perceptions about the impact of COVID-19 on agriculture and livelihoods in Senegal.

CONTEXT: The global COVID-19 pandemic has produced a variety of unanticipated shocks to farming and socio-economic systems around the world. In case of Senegal, the country was already facing number of challenges at the inception of the pandemic, including high rates of poverty, prevalence of food insecurity, combined with other biophysical and socioeconomic challenges faced generally in Sub-Saharan Africa. OBJECTIVE: To understand farmer perceptions of the potential impacts of COVID-19 on agricultural systems and social well-being of smallholder farmers in Senegal. Particular attention was given to potential vulnerabilities and resilience in the targeted farming systems. METHODS: A survey was developed to better understand smallholder farmer perceptions regarding the anticipated impacts of COVID-19 on their agriculture practices and social well-being. The survey was administered (between June 5 and June 20) with smallholder farmers (n = 872) in 14 regions covering all agroecological zones. Variables of interest included perceptions of potential impact on farming systems, agricultural productivity, communities, economics, markets, labor, gendered division of labor, food security, and community well-being. RESULTS AND CONCLUSIONS: Across the three farming systems examined (cropping, livestock, and horticulture) significant majorities expressed concerns related to access to inputs, ability to plant (cropping, horticulture), reduction of yields (cropping, horticulture), ability to feed livestock, ability to sell livestock, and the ability to hire labor (horticulture). The majority of respondents also expressed concern that COVID-19 would make it more difficult to get enough food on a regular basis for their household (82.5%); that the markets where they purchase food will either be closed or significantly disrupted (79.5%); that the price of food would increase (73.5%); and the market where they sell their produce/livestock will be either closed or significantly disrupted (73.2%). SIGNIFICANCE: Anticipated impacts of COVID-19 on agriculture will be felt on both the biophysical aspects such as production and access to inputs and socioeconomic aspects such as access to labor, markets, or rapid shifts in demand. Results support the need to use farming systems approach to gather perceived and actual impacts of COVID-19 and warrants a more in-depth examination of agronomic and biophysical issues as well as the impact on the livelihoods and social well-being of families at community and household levels. Further examination will help identify the characteristics that strengthen smallholder farming systems resilience to adjust to anticipated and unanticipated shocks, such as COVID-19, to decrease the negative impacts and increase the rate of recovery.

Projecting potential impact of COVID-19 on major cereal crops in Senegal and Burkina Faso using crop simulation models.

CONTEXT: The rapid emergence of COVID-19 could have direct and indirect impacts on food production systems and livelihoods of farmers. From the farming perspective, disruption of critical input availability, supply chains and labor, influence crop management. Disruptions to food systems can affect (a) planting area; and (b) crop yields. OBJECTIVES: To quantify the impacts of COVID-19 on major cereal crop's production and their cascading impact on national economy and related policies. METHODS: We used the calibrated crop simulation model (DSSAT suite) to project the impact of potential changes in planting area and grain yield of four major cereal crops (i.e., rice, maize, sorghum, and millet) in Senegal and Burkina Faso in terms of yield, total production, crop value and contribution to agricultural gross domestic product (GDP). Appropriate data (i.e., weather, soil, crop, and management practices) for the specific agroecological zones were used as an input in the model. RESULTS AND CONCLUSIONS: The simulated yields for 2020 were then used to estimate crop production at country scale for the matrix of different scenarios of planting area and yield change (-15, -10, -5, 0, +5, +10%). Depending on the scenario, changes in total production of four cereals combined at country levels varied from 1.47 M tons to 2.47 M tons in Senegal and 4.51 M tons to 7.52 M tons in Burkina Faso. The economic value of all four cereals under different scenarios ranged from $771 Million (M) to $1292 M in Senegal and from $1251 M to $2098 M in Burkina Faso. These estimated total crop values under different scenarios were compared with total agricultural GDP of the country (in 2019 terms which was $3995 M in Senegal and $3957 M in Burkina Faso) to assess the economic impact of the pandemic on major cereal grain production. Based on the scenarios, the impact on total agricultural GDP can change -7% to +6% in Senegal and - 8% to +9% in Burkina Faso. SIGNIFICANCE: Results obtained from this modeling exercise will be valuable to policymakers and end-to-end value chain practitioners to prepare and develop appropriate policies to cope or manage the impact of COVID-19 on food systems.

Setting research priorities for tackling climate change.

Addressing the complex issues related to climate change requires multiple innovative approaches to identify research priorities involving multidisciplinary research teams. Participatory approaches with a variety of perspectives were used to gain insights into critical issues such as defining and understanding sustainable intensification, climate smart agriculture, and soil fertility prioritization in sub-Saharan Africa. This analysis drew on the foundation principles of participatory research and fundamental facilitation skills, while grounded in scientific knowledge and understanding of these complex issues. This approach essentially incorporates the relevant principles of participatory learning and action, primarily designed for development projects, with a new set of players within the research and policy domain. The results of three case studies that utilized participatory techniques with a set of multidisciplinary research teams are presented. The case studies were: (i) Feed the Future Sustainable Intensification Innovation Lab (SIIL) proposal development grounded in country-led and national priorities in Bangladesh, Tanzania, and Cambodia; (ii) climate smart agriculture and sustainable intensification assessment and priority setting in Rwanda; and (iii) soil fertility prioritization in sub-Saharan Africa. We discuss how the future directions of such initiatives were shaped for improved outcomes.

Approaches to improve soil fertility in sub-Saharan Africa.

Soil fertility provides the foundation for nutritious food production and resilient and sustainable livelihoods. A comprehensive survey and summit meeting were conducted with the aims of understanding barriers to enhancing soil fertility in sub-Saharan Africa and providing evidence-based recommendations. The focus regions were West Africa, East Africa, the Great Lakes region, and Ethiopia. Overall recommendations were developed with four emerging themes: (1) strengthening inorganic fertilizer-based systems, (2) access to and use of quality organic inputs, (3) capacity building along the entire knowledge-transfer value chain, and (4) strengthening farming systems research and development across biophysical and socio-economic factors. The evidence-based process and methodology for prioritizing these recommendations makes these findings useful for setting out action plans for future investments and strategies. Access to inorganic fertilizer, its use, and related implementation issues were prominent considerations; nevertheless, biophysical and socio-economic barriers and solutions were identified as equally important to building soil fertility and natural resources. Soil management initiatives should focus on providing holistic solutions covering both biophysical and socio-economic aspects along the entire value chain of actors and creating an enabling environment for adoption. A broader view of soil fertility improvement using all available options including both inorganic and organic sources of nutrients and farming system approaches are highly recommended.

[Differences of analgesic efficacy and complication rates between ultrasound and nervestimulator guided peripheral nerve catheters : Database analysis on patient-relevant target parameters]. / Vergleich der Analgesiequalität und Komplikationen von ultraschall- und nervenstimulatorgesteuerten peripheren Nervenkathetern : Datenbankanalyse zu patientenrelevanten Zielparametern.

BACKGROUND: Peripheral nerve catheters (PNC) play an important role in postoperative pain treatment following major extremity surgery. There are several trials reported in the literature which investigated the efficacy and safety of ultrasound (US) and nerve stimulator (NS) guided PNC placement; however, most of these trials were only small and focused mainly on anesthesiologist-related indicators of block success (e.g. block onset time and procedure time) but not primarily on patient-related outcome data including postoperative pain during movement. AIM: This retrospective analysis compared the analgesic efficacy and safety of US versus NS guided peripheral nerve catheters (PNC) for postoperative pain therapy in a large cohort of patients. MATERIAL AND METHODS: Data of patients (June 2006-December 2010) treated with US (nus = 368 June 2008-December 2010) and NS (nns = 574, June 2006-May 2008) guided PNC were systematically analyzed. Apart from demographic data, postoperative pain scores [numeric rating scale (NRS): 0-10] on each treatment day, the number of patients with need for additional opioids, cumulative local anesthetic consumption and catheter-related complications were compared. RESULTS: On the day of surgery patients treated with US-guided PNC reported lower NRS at rest (p = 0.034) and during movement (p < 0.001). Additionally, the number of patients requiring additional opioids on the day of surgery was lower in the US group (absolute difference 12.4 %, p = 0.001). Furthermore, the number of multiple puncture attempts (absolute difference 5.6 %, p < 0.001) and failed catheter placements (absolute difference 3.4 %, p = 0.06) were lower in the US group. There were no patients in both groups with long-lasting neurological impairment. CONCLUSION: This database analysis demonstrated that patients treated with US-guided PNC reported significantly lower postoperative pain scores and the number of patients requiring additional opioids was significantly lower on the day of surgery. The numbers of multiple punctures and failed catheter placements were reduced in the US group, which might be seen as an advantage of US-guided regional anaesthesia.

Semi-selective broth improves screening for methicillin-resistant Staphylococcus aureus.

OBJECTIVES: To evaluate two enrichment broths for methicillin-resistant Staphylococcus aureus (MRSA) detection and compare results with direct plating. METHODS: Swabs from 1224 patients were re-analysed for MRSA in a central laboratory (Münster) using six methods. Swabs were suspended in 0.5 mL of non-selective enrichment broth (NB) and vortexed. Aliquots of 100 microL were inoculated on/into: (I) ChromID MRSA agar; (II) Columbia sheep blood (5%) agar (BA) and ChromID MRSA; (III, IV) NB incubated overnight followed by plating on BA and ChromID MRSA; and (V, VI) a semi-selective broth containing cefoxitin and aztreonam (TSB-SSI) incubated overnight followed by plating on BA and ChromID MRSA. In III-VI, 100 microL of the enriched broth was plated on each agar. RESULTS: The combined MRSA-positive rate was 21.5%. MRSA isolates detected by each method were: TSB-SSI, n = 223; NB, n = 205; BA and ChromID MRSA, n = 203; ChromID MRSA alone, n = 183. TSB-SSI detected more positive throat samples than the comparators and significantly reduced methicillin-susceptible S. aureus (MSSA) growth. The maximum sensitivity obtained was only 85%, possibly due to the study design using pre-used swabs and dilution of swab material. For 997 samples, results from Münster were compared with initial results. Peripheral laboratories identified 172 MRSA compared with Münster where 186, 186 and 204 MRSA were found for direct plating, NB and TSB-SSI broth, respectively. CONCLUSIONS: TSB-SSI was superior to both NB and direct plating on ChromID MRSA and BA. Despite re-using swabs for the study, we showed that routine diagnostic screening could be significantly improved, using a semi-selective enrichment broth.

Evolutionary trends in the genus Bordetella.

The genus Bordetella comprises seven species with pathogenic potential for different host organisms. This article attempts to review our current knowledge about the systematics and evolution of this important group of pathogens, their relationship to environmental microorganisms and about molecular mechanisms of host adaptation.

Representational difference analysis identifies a strain-specific LPS biosynthesis locus in Bordetella spp.

Bordetella pertussis and B. bronchiseptica are genetically very closely related but differ significantly in their virulence properties. Using Representational Difference Analysis (RDA), 11 DNA fragments specific for B. pertussis Tohama I or B. bronchiseptica BB7865 were identified. All B. bronchiseptica BB7865-derived fragments also hybridized with chromosomal DNA from B. parapertussis but not from the B. pertussis strains Tohama I and W28, underlining the close phylogenetic relationship between B. bronchiseptica and B. parapertussis. The B. pertussis type strain BP18323 is a special case, as it contains DNA sequences characteristic for both B. pertussis and B. bronchiseptica. As demonstrated by pulsed-field gel electrophoresis, several of the BB7865-derived fragments are present on a single 30-kb XbaI fragment. Based on the sequences of putative coding regions, four of these fragments may code for proteins involved in carbohydrate metabolism or transport. In agreement with this notion, a mutant for one of these loci synthesizes a significantly altered lipopolysaccharide that lacks the O-specific side chains. The analysis of the corresponding genomic region in various Bordetella species showed that this locus is present in B. bronchiseptica and B. parapertussis but not in B. pertussis. This confirms that the RDA approach has identified a novel strain-specific LPS biosynthesis locus which accounts for the differences between the LPS structures elaborated by different Bordetella species.

Specific binding of the Listeria monocytogenes transcriptional regulator PrfA to target sequences requires additional factor(s) and is influenced by iron.

The PrfA protein, which is a member of the Crp/Fnr family of prokaryotic transcription activators, regulates the virulence genes of Listeria monocytogenes. In this work, specific binding of PrfA to its target DNA was determined by electrophoretic mobility-shift assays (EMSAs) using cell-free extracts from the two L. monocytogenes strains EGD and NCTC 7973. PrfA-specific binding differs between the two strains, even when the concentration of PrfA was adjusted to similar levels. Both strains exhibited increased PrfA-specific binding after a shift into minimal essential medium (MEM) without showing a significant change in the amount of PrfA protein, relative to extracts from bacteria grown in brain-heart infusion (BHI). The purified PrfA protein from strain EGD produced in Escherichia coli did not exhibit specific binding to the target DNA but did so upon addition of PrfA-free extracts from various Listeria species and Bacillus subtilis. The observed activation of PrfA seems to be caused by a PrfA-activating factor (Paf), which is probably a protein since elevated temperature, but not RNase treatment, destroyed the activation potential of such PrfA-free extracts. Moreover, fractionation of these extracts by sucrose gradient centrifugation yielded the Paf activity in a fraction sedimenting at 3.2 S. Specific binding of PrfA-containing extracts from strain EGD to the hly and actA promoter sequences was strongly inhibited by iron, whereas that of extracts from strain NCTC 7973 was only slightly reduced. The iron effect seems to be mediated by Paf rather than by PrfA itself.

Cancer incidence in a group of workers potentially exposed to ethylene oxide.

BACKGROUND: Cytogenetic changes associated with ethylene oxide (ETO) exposure at a worksite prompted a study of cancer incidence in that cohort. METHOD: Cancer incidence through 31 December 1987 was ascertained in a cohort of 1132 individuals employed at the worksite at any time from 1 July 1974 through 30 September 1980, the period of potential exposure to ETO at the plant. The number of observed cancers was compared with that expected based on age- and sex-specific incidence rates reported by the National Cancer Institute's Surveillance Epidemiology and End Results Program. Standardized morbidity ratios (SMR) were calculated separately for regular and temporary employees. RESULTS: Of the 28 cancers observed in the cohort, 12 were breast cancers. The SMR for breast cancer among regular female employees ranged from 2.55 (95% CI: 1.31-4.98, P = 0.02) to 1.70 (95% CI: 0.89-3.23, P = 0.09) depending on calendar year of follow-up, assumptions about completeness of follow-up, and the reference rates used. The excess of breast cancer over expected in regular female employees diminished over time. No statistically significant excess of breast cancer was noted for temporary female employees at any point during follow-up. No increase in cancer incidence was found over that expected for any cancer sites associated with ETO in previous studies--leukaemia, brain, pancreas and stomach. CONCLUSIONS: Factors such as appropriateness of latency periods, length of follow-up and lack of a common histopathological type need to be considered in evaluating the excesses in observed breast cancer incidence, which diminished over time.