The mechanism of pyridine hydrogenolysis on molybdenum-containing catalysts : II. Hydrogenation of pyridine to piperidine

The kinetics of pyridine hydrogenation was studied at high hydrogen pressures on a Mo-Al oxide and a Co-Mo-Al oxide catalyst. The rate equation was found to be r = kPpyrPH2n/Ppyro, in which n is 1.5 at 300 and 375 °C and 1.0 at 250 °C. This rate equation can be derived assuming strong adsorption of pyridine and its products with identical adsorption constants.\ud The (hydro)cracking of piperidine appears to have a low order in hydrogen, probably lower than 0.5.\ud The adsorption behavior of nitrogen bases and hydrogen on alumina and the molybdenum-containing catalysts was investigated by the gas chromatographic method. The adsorption of the nitrogen bases appeared to be very strong on both catalysts, and varied in the order piperidine > pyridine > ammonia.\ud Hydrogen also showed a strong adsorption. Hydrogen and nitrogen bases appeared to adsorb on different sites

Soil nitrogen supply of peat grasslands estimated by degree days and soil organic matter content

Accurate estimates of the quantity and rate of soil nitrogen supply (SNS) are essential to increase soil and farm N use efficiencies, in particular for soils high in organic matter. The objective of this work was to enhance the empirical understanding of the SNS of dairy grasslands on peat soils, using soil properties and weather variables. Data were collected from studies on herbage N uptake carried out between 1992 and 2017 in the western peat district of the Netherlands. For the period between March to mid October, SNS was estimated from the sum of mean growing season daily temperatures, soil organic matter (SOM) and applied calcium ammonium nitrate (CAN) N with a residual standard error of 25–27 kg ha−1. Each °C growing season temperature sum affected SNS by 78–90 g ha−1 and each g SOM per 100 g dry soil affected SNS by 3.6–3.9 kg ha−1, respectively. SNS was equally estimated for conditions with and without CAN fertilisation. Validation with data from independent field trials showed similar impacts of SOM and growing season temperature sum on SNS. The error of prediction of the presented models, however, was still too large for direct on-farm application and led to underestimations for a specific site. Nevertheless, the obtained models allow for an increased understanding of soil and farm N balances. The models can therefore be used for improved temporal and spatial SNS-adapted farming practice advice, which can potentially lead to reduced soil and farm N surpluses.</p

A coating from nature

For almost a century, petrochemical-based monomers like acrylates have been widely used as the basis for coatings, resins, and paints. The development of sustainable alternatives, integrating the principles of green chemistry in starting material, synthesis process, and product function, offers tremendous challenges for science and society. Here, we report on alkoxybutenolides as a bio-based alternative for acrylates and the formation of high-performance coatings. Starting from biomass-derived furfural and an environmentally benign photochemical conversion using visible light and oxygen in a flow reactor provides the alkoxybutenolide monomers. This is followed by radical (co) polymerization, which results in coatings with tunable properties for applications on distinct surfaces like glass or plastic. The performance is comparable to current petrochemical-derived industrial coatings

Assessment of nutritional status in haemodialysis patients using PG-SGA and handgrip strength

In this cross-sectional study, we primarily aimed to assess prevalence of malnutrition by the Patient Generated Subjective Global Assessment (PGSGA), and muscle strength in haemodialysis patients. Second, we explored to which extent these patients are able to complete the patient component of the PG-SGA, aka PG-SGA Short Form (SF) (weight, intake, symptoms, activities/functioning) independently

A sustainable polymer and coating system based on renewable raw materials

Paints and coatings are widely used in modern society and their current production is mainly dependent on the petrochemical industry. The establishment of processes using sustainable alternative monomers based on biorenewable resources, using exclusively biobased reagents and green synthetic transformations are highly warranted for a more sustainable future. Herein, we report on a sustainable polymer and coating system based on the monomer methoxybutenolide, a biobased acrylate alternative. Methoxybutenolide and the comonomer dodecyl vinyl ether are synthesized from biobased platform chemicals using the environmentally benign synthetic transformations photooxygenation and vinylation. For the photooxygenation, a biobased photosensitizer was developed showing high quantum yields. The monomers were copolymerized using biomass derived (photo)initiators to yield fully biobased polymers and coatings with properties comparable to acrylate based coatings

Limited effect of duration of CMV infection on adaptive immunity and frailty:insights from a 27-year-long longitudinal study

Objectives: Cytomegalovirus infection is thought to affect the immune system and to impact general health during ageing. Higher CMV-specific antibody levels in the elderly are generally assumed to reflect experienced viral reactivation during life. Furthermore, high levels of terminally differentiated and CMV-specific T cells are hallmarks of CMV infection, which are thought to expand over time, a process also referred to as memory inflation.Methods: We studied CMV-specific antibody levels over ~ 27 years in 268 individuals (aged 60-89 years at study endpoint), and to link duration of CMV infection to T-cell numbers, CMV-specific T-cell functions, frailty and cardiovascular disease at study endpoint.Results: In our study, 136/268 individuals were long-term CMV seropositive and 19 seroconverted during follow-up (seroconversion rate: 0.56%/year). CMV-specific antibody levels increased slightly over time. However, we did not find an association between duration of CMV infection and CMV-specific antibody levels at study endpoint. No clear association between duration of CMV infection and the size and function of the memory T-cell pool was observed. Elevated CMV-specific antibody levels were associated with the prevalence of cardiovascular disease but not with frailty. Age at CMV seroconversion was positively associated with CMV-specific antibody levels, memory CD4+ T-cell numbers and frailty.Conclusion: Cytomegalovirus-specific memory T cells develop shortly after CMV seroconversion but do not seem to further increase over time. Age-related effects other than duration of CMV infection seem to contribute to CMV-induced changes in the immune system. Although CMV-specific immunity is not evidently linked to frailty, it tends to associate with higher prevalence of cardiovascular disease.</p

Technologic (r)evolution leads to detection of more sentinel nodes in patients with melanoma in the head and neck region

Sentinel lymph node (SN) biopsy (SNB) has proven to be a valuable tool for staging melanoma patients. Since its introduction in the early 1990s, this procedure has undergone several technologic refinements, including the introduction of SPECT/CT, as well as radioguidance and fluorescence guidance. The purpose of the current study was to evaluate the effect of this technologic evolution on SNB in the head and neck region. The primary endpoint was the false-negative (FN) rate. Secondary endpoints were number of harvested SNs, overall operation time, operation time per harvested SN, and postoperative complications. Methods: A retrospective database was queried for cutaneous head and neck melanoma patients who underwent SNB at The Netherlands Cancer Institute between 1993 and 2016. The implementation of new detection techniques was divided into 4 groups: 1993-2005, with preoperative lymphoscintigraphy and intraoperative use of both a y-ray detection probe and patent blue (n = 30); 2006-2007, with addition of preoperative road maps based on SPECT/CT (n = 15); 2008-2009, with intraoperative use of a portable y-camera (n = 40); and 2010-2016, with addition of near-infrared fluorescence guidance (n = 192). Results: In total, 277 patients were included. At least 1 SN was identified in all patients. A tumor-positive SN was found in 59 patients (21.3%): 10 in group 1 (33.3%), 3 in group 2 (20.0%), 6 in group 3 (15.0%), and 40 in group 4 (20.8%). Regional recurrences in patients with tumor negative SNs resulted in an overall FN rate of 11.9% (group 1, 16.7%; group 2, 0%; group 3, 14.3%; group 4, 11.1%). The number of harvested nodes increased with advancing technologies (P = 0.003), whereas Breslow thickness and operation time per harvested SN decreased (P = 0.003 and P = 0.017, respectively). There was no significant difference in percentage of tumor-positive SNs, overall operation time, and complication rate between the different groups. Conclusion: The use of advanced detection technologies led to a higher number of identified SNs without an increase in overall operation time, possibly indicating an improved surgical efficiency. Operation time per harvested SN decreased; the average FN rate remained 11.9% and was unchanged over 23 y. There was no significant change in postoperative complication rate.Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas

The best of both worlds: a hybrid approach for optimal pre- and intraoperative identification of sentinel lymph nodes

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas