Insights into HMF catalysis

In recent decades, the concept of biorefinery has gained considerable momentum as a promising approach to obtain energy commodity chemicals. 5-hydroxymethylfurfural (HMF) is one of the most promising building blocks for biobased chemicals and a strong candidate for large scale production. However, one of the main factors holding its transition is the need for green, sustainable, and financially feasible processes. This review provides a critical assessment of the progresses made towards catalytic and autocatalytic systems used for HMF production, as well as advancements in catalyst research, their mechanisms analyses, efficiency and sustainability. It also provides key information which can facilitate the selection and development of catalysts for HMF production

Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods

Gibbons CL, Mangen M-JJ, Plaß D, et al. Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods. BMC Public Health. 2014;14(1): 147.Background: Efficient and reliable surveillance and notification systems are vital for monitoring public health and disease outbreaks. However, most surveillance and notification systems are affected by a degree of underestimation (UE) and therefore uncertainty surrounds the 'true' incidence of disease affecting morbidity and mortality rates. Surveillance systems fail to capture cases at two distinct levels of the surveillance pyramid: from the community since not all cases seek healthcare (under-ascertainment), and at the healthcare-level, representing a failure to adequately report symptomatic cases that have sought medical advice (underreporting). There are several methods to estimate the extent of under-ascertainment and underreporting. Methods: Within the context of the ECDC-funded Burden of Communicable Diseases in Europe (BCoDE)-project, an extensive literature review was conducted to identify studies that estimate ascertainment or reporting rates for salmonellosis and campylobacteriosis in European Union Member States (MS) plus European Free Trade Area (EFTA) countries Iceland, Norway and Switzerland and four other OECD countries (USA, Canada, Australia and Japan). Multiplication factors (MFs), a measure of the magnitude of underestimation, were taken directly from the literature or derived (where the proportion of underestimated, under-ascertained, or underreported cases was known) and compared for the two pathogens. Results: MFs varied between and within diseases and countries, representing a need to carefully select the most appropriate MFs and methods for calculating them. The most appropriate MFs are often disease-,country-, age-, and sex-specific. Conclusions: When routine data are used to make decisions on resource allocation or to estimate epidemiological parameters in populations, it becomes important to understand when, where and to what extent these data represent the true picture of disease, and in some instances (such as priority setting) it is necessary to adjust for underestimation. MFs can be used to adjust notification and surveillance data to provide more realistic estimates of incidence

Erratum to: Methods for evaluating medical tests and biomarkers

[This corrects the article DOI: 10.1186/s41512-016-0001-y.]

Evidence synthesis to inform model-based cost-effectiveness evaluations of diagnostic tests: a methodological systematic review of health technology assessments

Background: Evaluations of diagnostic tests are challenging because of the indirect nature of their impact on patient outcomes. Model-based health economic evaluations of tests allow different types of evidence from various sources to be incorporated and enable cost-effectiveness estimates to be made beyond the duration of available study data. To parameterize a health-economic model fully, all the ways a test impacts on patient health must be quantified, including but not limited to diagnostic test accuracy. Methods: We assessed all UK NIHR HTA reports published May 2009-July 2015. Reports were included if they evaluated a diagnostic test, included a model-based health economic evaluation and included a systematic review and meta-analysis of test accuracy. From each eligible report we extracted information on the following topics: 1) what evidence aside from test accuracy was searched for and synthesised, 2) which methods were used to synthesise test accuracy evidence and how did the results inform the economic model, 3) how/whether threshold effects were explored, 4) how the potential dependency between multiple tests in a pathway was accounted for, and 5) for evaluations of tests targeted at the primary care setting, how evidence from differing healthcare settings was incorporated. Results: The bivariate or HSROC model was implemented in 20/22 reports that met all inclusion criteria. Test accuracy data for health economic modelling was obtained from meta-analyses completely in four reports, partially in fourteen reports and not at all in four reports. Only 2/7 reports that used a quantitative test gave clear threshold recommendations. All 22 reports explored the effect of uncertainty in accuracy parameters but most of those that used multiple tests did not allow for dependence between test results. 7/22 tests were potentially suitable for primary care but the majority found limited evidence on test accuracy in primary care settings. Conclusions: The uptake of appropriate meta-analysis methods for synthesising evidence on diagnostic test accuracy in UK NIHR HTAs has improved in recent years. Future research should focus on other evidence requirements for cost-effectiveness assessment, threshold effects for quantitative tests and the impact of multiple diagnostic tests

Erratum to: Methods for evaluating medical tests and biomarkers

[This corrects the article DOI: 10.1186/s41512-016-0001-y.]

Intérêts de l'examen foeto-placentaire dans l'exploration des morts foetales in utero (à propos de 44 cas au CHU de Poitiers)

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Production of HMF in high yield using a low cost and recyclable carbonaceous catalyst

In this study, they were produced by hydrothermal carbonization of softwood pulp and functionalized using H2SO4. These newly synthesized catalysts were used in a one-pot reaction system where ionic liquid [BMIM+][Cl-] acted as a solvent and MIBK acted as the organic phase in the conversion of fructose to HMF. Using response surface methodology, molar yields as high as 98.6 % were obtained at mild conditions of 112 °C and 24 minutes with a catalyst load of 5% weight. The catalyst was easily recovered by filtration and used four times with minor loss in catalytic activity. XRD patterns showed that the material remained stable through the reaction conditions

Polyvinyl sulfonated catalyst and the effect of sulfonic sites on the dehydration of carbohydrates

Several biobased platform chemicals have been identified as potential replacements of oil-based product, such as fuels and polymers. One of them, 5-hydroxymethylfurfural (HMF), has the potential to be transformed in a myriad of products, such as fungicides, fuels, and plastics. Environmentally and financially sustainable production of HMF has been one of the main bottlenecks for its commercialization at the industrial level. Here is presented a low-cost, tunable polyvinyl-based solid catalyst capable of efficiently transforming carbohydrates into HMF. The catalyst was produced using polyvinyl alcohol and sulfosuccinic acid (SSA) as the crosslinker. Adjusting crosslinking concentration had measurable effects on the physical properties and the efficiency of the catalyst. The crosslinking degree was observed to affect the thermal stability, the crystallinity, and the functional sites, providing an opportunity to fine tune the material to the reaction’s needs. At the highest SSA concentration, SO3H functional sites reached 1.7 mmol/g, and 3.6 mmol/g total acid sites. HMF synthesis was tested in ionic liquid [BMIM][Cl] and water. The use of ionic liquids reduced considerably the reaction temperature and time needed for quantitative yields from fructose. Optimal reaction conditions were found by response surface methodology, resulting in an HMF yield of 94.3% after 4 min at 125 °C from fructose. A kinetic model showed that HMF degradation proceeded via HMF self-condensation or self-etherification, and not through rehydration. The PVA-SSA catalyst was also tested on glucose and sucrose, with moderate yields (25% and 63.9% respectively) for both. The material shows promise as a highly tunable, recyclable catalyst

Synthesis of hydroxymethylfurfural and furfural from hardwood and softwood pulp using ferric sulphate as catalyst

Hydroxymethylfurfural (HMF) and furfural are promising chemicals for the creation of a bio-based economy. The development of an inexpensive catalytic system for converting cellulosic biomass into these chemicals is an important step in this regard. Ferric sulphate is a common, cheap and non-toxic Lewis acid that has been used to catalyse reactions such as wood depolymerisation. In this work, ferric sulphate was used to help the production of HMF and furfural from hardwood and softwood pulps. It was found that for hardwood pulp, the use of ferric sulphate alone gave a maximum HMF yield of 31.6 mol%. The addition of the ionic liquid [BMIM]Cl or HCl as co-catalysts did not lead to an increase in the yields obtained. A prior decationisation step, however, resulted in HMF yields of 50.4 mol%. Softwood pulp was harder to depolymerise than hardwood, with a yield of 28.7% obtained using ferric sulphate alone. The maximum HMF yield from softwood- 37.9 mol%- was obtained using a combination of ferric sulphate and dilute HCl. It was thus concluded that ferric sulphate is a promising catalyst for HMF synthesis from cellulosic biomass

Valorization of Decationized Newsprint to Levulinic Acid

As of today, most chemical products are fossil-based. The environmental concerns of fossil resources due to their constant misuse have led to the exploration of bio-based alternatives. Biomass comprising industrial and municipal wastes, agricultural residues, forest residues, and natural herbaceous plants can favorably replace fossil fuel to produce chemicals. In this study, softwood and hardwood pulps were used to synthesize levulinic acid. Prior to a dilute acid hydrolysis step, the wood pulps were decationized overnight with 0.2 M HCl. The effects of the major reaction conditions including reaction temperature, time, and HCl concentration on the yield of levulinic acid was studied via a central composite design. Levulinic acid yields from softwood and hardwood pulps reached 50.30 mol% and 68.85 mol%, respectively, at optimum reaction conditions. When newsprints were tested using the optimized parameters for softwood and hardwood conversion, levulinic acid yields of 66.25 mol% and 79.65 mol% were obtained, respectively. A kinetic model was developed to predict the yields of glucose, hydroxymethylfurfural, and levulinic acid from the HCl-pretreated newsprint. The analysis of the kinetic parameters and the results of the response surface methodology experiments provided optimized conditions for levulinic acid production