Endgroup determination of synthetic polymers by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

AbstractElectrospray ionization (ESI) was performed on a Fourier transform ion cyclotron resonance mass spectrometer for the endgroup and monomer mass determination of three poly(oxyalkylene)s in the mass range of 400–8000 Da. A combined use of the multiple charge states observed with ESI, leads to a threefold increase in accuracy of the endgroup and monomer determination. The improvement is attributed to the increased number of datapoints used for the regression procedure, yielding more accurate results. Endgroup masses are determined with a mass error better than 5 and 75 millimass units for the molecular weight range of 400–4200 and 6200–8000 Da, respectively. A mass error of better than 1 millimass unit was observed for all monomer mass determinations. With ESI, endgroup and monomer masses have been determined for poly(ethylene glycol) oligomers with a mass higher than 8000 Da. This is almost two times higher than observed with matrix-assisted laser desorption/ionization on the same instrument

Geological and hydrogeological investigations in the Colchester Northern Gateway boreholes : February 2020 survey

This research report describes borehole geophysical and passive seismic surveys done at the Colchester Northern Gateway (CNG) geothermal district heat network and housing development in Essex, UK, between 10-13 February 2020. The first part of the report introduces the project context, the second part describes survey methods, and the third presents the ‘baseline survey’ results and stratigraphic interpretation. The final section summarises the key learnings, relevance of the findings to future geothermal district heating schemes in the Chalk and London Basin, and makes some recommendations for follow-up monitoring research. Five recently drilled production/injection boreholes at CNG were logged with Calliper, Temperature and Conductivity, Natural Gamma, Optical Televiewer (OPTV) tools. Some of the holes also had Resistivity and Impeller flow tools run but results were inconclusive. A site-wide Tromino H/V passive seismic survey was acquired to characterise the resonant frequency of the subsoils between the boreholes, to aid stratigraphic correlation, profile the concealed chalk ‘rockhead’ surface (i.e. depth of bedrock aquifer), and look for any evidence of the presence of faults/fracture zone, and characterise the thickness of karst and weathering profiles. The main geological formation boundaries were identified based on a combination of interpretation of Natural Gamma logs and correlation of sedimentary features observed in the OPTV images. The eroded top of the Newhaven Chalk is around 72 m below ground level (-24 m OD) in all five boreholes (BH1-5). The high-resolution OPTV images provide rich visual information on the fracture state of the upper ‘productive’ part of the chalk aquifer. A notable feature in BH4 is an 18 m long NW-SE orientated open vertical fracture that persists through the Newhaven Chalk but terminates at the top of the Seaford Chalk. The OPTV data also aids identification of key litho-stratigraphic marker horizons, such as tabular flint bands, hard grounds and marls seams. The Natural Gamma aids identification of key marls, such as the Buckle Marl and Shoreham Marls and the top and base of the London Clay and top of Chalk. Marls and flint bands are useful litho-stratigraphic markers for site- to regional-scale correlation and structural analysis, and for developing hydrogeological and thermo-geological conceptual and observational geo-models to inform the set-up of numerical flow models (e.g. FeFLOW models). The interpretation of the new survey data concluded that the near-surface geology at CNG comprises c.72 m of thin Superficial deposits and Palaeogene sediments resting on Cretaceous Chalk bedrock (White Chalk Sub-group). The two deepest (200 m) boreholes (BH2 and BH4) penetrate 4-5 m of superficial deposits (cover sand and gravels) resting on c.36 m of London Clay, c.8.5 m of Harwich Formation, c.10 m of Lambeth Group, c.12 m of Thanet Formation, c.23 m of slightly karstified and fractured basal Newhaven Chalk, c.59.4 m of Seaford Chalk and terminate within c.31 m of upper Lewis Nodular Chalk Formation. Groundwater temperature profiling in February 2020 suggests a shallow geothermal gradient of around 2.4°C per 100 m in the top 200 m of the Chalk aquifer in the Colchester area. Under natural conditions (i.e. no influence from other subsurface users), groundwater source heat pump schemes can therefore expect seasonally stable ambient source temperatures of around 11.7°C and 14.3°C at 100 m and 200 m depths, respectively, with 130m open loop schemes predicted to yield borehole inflow temperatures of around 12.5°C all year round (assuming no thermal interactions/breakthrough), making open loop ground source heat pump schemes a viable option for low carbon/no carbon heating systems. Pumping tests in the CNG wells (undertaken by the developer Amphora Energy Ltd in c.2019) yielded 2 to 10 l/s. The highest yields were from BH4 & 5 located on the far western side of the CNG development site and were attributed to the switch to a reverse-circulation drilling technique, however the presence of karstified open fractures (BH4) may also be a contributing factor. Open loop GSHP heating capacities of between 60 and 300 kW thermal per 130m well-doublets (depending on local aquifer properties) are therefore probably feasible for similar schemes in the region, assuming a sustainable thermal productivity (ΔTgw) of 7°C (i.e. abstraction at 12.5°C and injection at 5.5°C). Larger yields may be possible using larger diameter boreholes and in more fractured, weathered or karstified parts of the aquifer (i.e. fracture systems associated with the major NW-SE bedrock lineaments described by Woods and Chacksfield (2012)). The passive seismic H/V data collected across the CNG site in 2020, prior to the new house construction, suggests chalk aquifer and seismic rockhead surface in-between the boreholes (BH1-5) is relatively level and planar at an elevation of around -24 m OD, although some karstification may have occurred in the upper 10-20m of the aquifer. This top chalk elevation is consistent with the old borehole records from the nearby Severalls Hospital. From interpretation of the closely-spaced H/V survey results there is no suggestion of a major fault/fracture system within the chalk at the CNG site, although there could be undetected fault systems at other locations in the region and potentially at depth in the area

Identification of a Response Amplitude Operator for Ships

At the European Study Group Mathematics with Industry 2012 in Eindhoven, the Maritime Research Institute Netherlands (MARIN) presented the problem of identifying the response amplitude operator (RAO) for a ship, given input information on the amplitudes of the sea waves and output information on the movement of the ship. We approach the problem from a threefold perspective: a direct least-squares approach, an approach based on truncated Fourier series, and an approach using low-dimensional measures of the RAO. We give a few recommendations for possible further investigations

Quantum computation by quantum-like systems

Using a quantumlike description for light propagation in nonhomogeneous optical fibers, quantum information processing can be implemented by optical means. Quantum-like bits (qulbits) are associated to light modes in the optical fiber and quantum gates to segments of the fiber providing an unitary transformation of the mode structure along a space direction. Simulation of nonlinear quantum effects is also discussed.Comment: 12 pages, Late

High viscosity preparative chromatography for food applications

The strength of chromatography lies in the ability of fine-tuning recovery for specific target components or fractions of interest. A downside of industrial chromatography is the need to dilute streams, as it is often applied today. This article challenges the conventional low concentration of input streams and investigates size exclusion chromatography at concentrated streams of high viscosity. Chromatographic operation with concentrated streams leads to an increased pressure drop over the column and decreased mass transfer kinetics, but also lower volumes compared to diluted streams. The objective of this research was to investigate separation performance and system dimensions as a function of viscosity for food type streams, in scenarios where viscosity is not caused by target components. Disadvantages due to increased stream volume with decreasing concentration and benefits due to decreased viscosity were evaluated, aiming to find minimal column volume. Separation performance was evaluated for a range of target components in a preparative lab-scale system using a size exclusion resin and mobile phase viscosities in the range of 1.2–8.7 mPa⋅s. Mobile phases were viscosified through addition of sucrose, glycerol, or dextran. Change in mass transfer resistance, measured via van Deemter curves, was related to the change in diffusivity through viscosity. The analysis of different viscosifying agents emphasized the influence of viscosity inside the pores, rather than viscosity of the bulk phase. The viscosity inside the pores was calculated via the partition coefficient of each viscosifying agent. Based on the slopes of van Deemter curves, column dimensions were calculated for different scenarios, assuming a non-compressible stationary phase. Column volume remained constant with stream dilution from 8.7 mPa⋅s down to about 2.5 mPa⋅s. However, at the same time column geometry changed to thinner and longer columns with decreasing viscosity, in order to accommodate throughput and pressure drop. When diluting to even lower viscosities, column volume increased, since stream viscosity is less sensitive to stream concentration at the low viscosity range. These results are relevant to a wide range of industries utilizing weak interaction chromatography, especially those where the main driver of process development is cost reduction and where a trade-off between purity, yield, and costs has to be made.</p

Elevated viscosities in a simulated moving bed for γ-aminobutyric acid recovery

Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.</p

Machine learning-based analysis of non-invasive measurements for predicting intracardiac pressures

Aims: Early detection of congestion has demonstrated to improve outcomes in heart failure (HF) patients. However, there is limited access to invasively haemodynamic parameters to guide treatment. This study aims to develop a model to estimate the invasively measured pulmonary capillary wedge pressure (PCWP) using non-invasive measurements with both traditional statistics and machine learning (ML) techniques. Methods and results: The study involved patients undergoing right-sided heart catheterization at Erasmus MC, Rotterdam, from 2017 to 2022. Invasively measured PCWP served as outcomes. Model features included non-invasive measurements of arterial blood pressure, saturation, heart rate (variability), weight, and temperature. Various traditional and ML techniques were used, and performance was assessed using R2 and area under the curve (AUC) for regression and classification models, respectively. A total of 853 procedures were included, of which 31% had HF as primary diagnosis and 49% had a PCWP of 12 mmHg or higher. The mean age of the cohort was 59 ± 14 years, and 52% were male. The heart rate variability had the highest correlation with the PCWP with a correlation of 0.16. All the regression models resulted in low R2 values of up to 0.04, and the classification models resulted in AUC values of up to 0.59. Conclusion: In this study, non-invasive methods, both traditional and ML-based, showed limited correlation to PCWP. This highlights the weak correlation between traditional HF monitoring and haemodynamic parameters, also emphasizing the limitations of single non-invasive measurements. Future research should explore trend analysis and additional features to improve non-invasive haemodynamic monitoring, as there is a clear demand for further advancements in this field.</p

Machine learning-based analysis of non-invasive measurements for predicting intracardiac pressures

Aims: Early detection of congestion has demonstrated to improve outcomes in heart failure (HF) patients. However, there is limited access to invasively haemodynamic parameters to guide treatment. This study aims to develop a model to estimate the invasively measured pulmonary capillary wedge pressure (PCWP) using non-invasive measurements with both traditional statistics and machine learning (ML) techniques. Methods and results: The study involved patients undergoing right-sided heart catheterization at Erasmus MC, Rotterdam, from 2017 to 2022. Invasively measured PCWP served as outcomes. Model features included non-invasive measurements of arterial blood pressure, saturation, heart rate (variability), weight, and temperature. Various traditional and ML techniques were used, and performance was assessed using R2 and area under the curve (AUC) for regression and classification models, respectively. A total of 853 procedures were included, of which 31% had HF as primary diagnosis and 49% had a PCWP of 12 mmHg or higher. The mean age of the cohort was 59 ± 14 years, and 52% were male. The heart rate variability had the highest correlation with the PCWP with a correlation of 0.16. All the regression models resulted in low R2 values of up to 0.04, and the classification models resulted in AUC values of up to 0.59. Conclusion: In this study, non-invasive methods, both traditional and ML-based, showed limited correlation to PCWP. This highlights the weak correlation between traditional HF monitoring and haemodynamic parameters, also emphasizing the limitations of single non-invasive measurements. Future research should explore trend analysis and additional features to improve non-invasive haemodynamic monitoring, as there is a clear demand for further advancements in this field.</p

The different risk of new-onset, chronic, worsening, and advanced heart failure:A systematic review and meta-regression analysis

Aims: Heart failure (HF) is a chronic and progressive syndrome associated with a poor prognosis. While it may seem intuitive that the risk of adverse outcomes varies across the different stages of HF, an overview of these risks is lacking. This study aims to determine the risk of all-cause mortality and HF hospitalizations associated with new-onset HF, chronic HF (CHF), worsening HF (WHF), and advanced HF. Methods and results: We performed a systematic review of observational studies from 2012 to 2022 using five different databases. The primary outcomes were 30-day and 1-year all-cause mortality, as well as 1-year HF hospitalization. Studies were pooled using random effects meta-analysis, and mixed-effects meta-regression was used to compare the different HF groups. Among the 15 759 studies screened, 66 were included representing 862 046 HF patients. Pooled 30-day mortality rates did not reveal a significant distinction between hospital-admitted patients, with rates of 10.13% for new-onset HF and 8.11% for WHF (p = 0.10). However, the 1-year mortality risk differed and increased stepwise from CHF to advanced HF, with a rate of 8.47% (95% confidence interval [CI] 7.24–9.89) for CHF, 21.15% (95% CI 17.78–24.95) for new-onset HF, 26.84% (95% CI 23.74–30.19) for WHF, and 29.74% (95% CI 24.15–36.10) for advanced HF. Readmission rates for HF at 1 year followed a similar trend. Conclusions: Our meta-analysis of observational studies confirms the different risk for adverse outcomes across the distinct HF stages. Moreover, it emphasizes the negative prognostic value of WHF as the first progressive stage from CHF towards advanced HF.</p

The different risk of new-onset, chronic, worsening, and advanced heart failure:A systematic review and meta-regression analysis

Aims: Heart failure (HF) is a chronic and progressive syndrome associated with a poor prognosis. While it may seem intuitive that the risk of adverse outcomes varies across the different stages of HF, an overview of these risks is lacking. This study aims to determine the risk of all-cause mortality and HF hospitalizations associated with new-onset HF, chronic HF (CHF), worsening HF (WHF), and advanced HF. Methods and results: We performed a systematic review of observational studies from 2012 to 2022 using five different databases. The primary outcomes were 30-day and 1-year all-cause mortality, as well as 1-year HF hospitalization. Studies were pooled using random effects meta-analysis, and mixed-effects meta-regression was used to compare the different HF groups. Among the 15 759 studies screened, 66 were included representing 862 046 HF patients. Pooled 30-day mortality rates did not reveal a significant distinction between hospital-admitted patients, with rates of 10.13% for new-onset HF and 8.11% for WHF (p = 0.10). However, the 1-year mortality risk differed and increased stepwise from CHF to advanced HF, with a rate of 8.47% (95% confidence interval [CI] 7.24–9.89) for CHF, 21.15% (95% CI 17.78–24.95) for new-onset HF, 26.84% (95% CI 23.74–30.19) for WHF, and 29.74% (95% CI 24.15–36.10) for advanced HF. Readmission rates for HF at 1 year followed a similar trend. Conclusions: Our meta-analysis of observational studies confirms the different risk for adverse outcomes across the distinct HF stages. Moreover, it emphasizes the negative prognostic value of WHF as the first progressive stage from CHF towards advanced HF.</p