A Coalescing Filter for Liquid-Liquid Separation and Multistage Extraction in Continuous-Flow Chemistry.

Presented here is the design and performance of a coalescing liquid-liquid filter, based on low-cost and readily available meltblown nonwoven substrates for separation of immiscible phases. The performance of the coalescer was determined across three broad classes of fluid mixtures: (i) immiscible organic/aqueous systems, (ii) a surfactant laden organic/aqueous system with modification of the type of emulsion and interfacial surface tension through the addition of sodium chloride, and (iii) a water-acetone/toluene system. The first two classes demonstrated good performance of the equipment in effecting separation, including the separation of a complex emulsion system for which a membrane separator, operating through transport of a preferentially wetting fluid through the membrane, failed entirely. The third system was used to demonstrate the performance of the separator within a multistage liquid-liquid counterflow extraction system. The performance, robust nature, and scalability of coalescing filters should mean that this approach is routinely considered for liquid-liquid separations and extractions within the fine chemical and pharmaceutical industry.

Descriptive account of the first use of the LeVe CPAP System, a new frugal CPAP System, in adult patients with COVID-19 Pneumonitis in Uganda.

BACKGROUND: Continuous positive airway pressure (CPAP) has been a key treatment modality for Coronavirus Disease 2019 (COVID-19) worldwide. Globally, the demand for CPAP outstripped the supply during the pandemic. The LeVe CPAP System was developed to provide respiratory support for treatment of COVID-19 and tailored for use in low- and middle-income country (LMIC) settings. Prior to formal trial approval, received in November 2021, these devices were used in extremis to support critically unwell adult patients requiring non-invasive ventilatory support. METHODS: This is a retrospective descriptive review of adult patients with COVID-19 pneumonitis, who were treated with advanced respiratory support (CPAP and/or high-flow nasal oxygen, HFNO) at Mengo Hospital, Uganda. Patients were treated with the LeVe CPAP System, Elisa CPAP and/or AIRVO™ HFNO. Treatment was escalated per standard local protocols for respiratory failure, and CPAP was the maximum respiratory support available. Data were collected on patient characteristics, length of time of treatment, clinical outcome, and any adverse events. RESULTS: Overall 333 patients were identified as COVID-19 positive, 44 received CPAP ± HFNO of which 43 were included in the study. The median age was 58 years (range 28-91 years) and 58% were female. The median duration of advanced respiratory support was 7 days (range 1-18 days). Overall (all device) mortality was 49% and this was similar between those started on the LeVe CPAP System and those started non-LeVe CPAP System devices (50% vs 47%). CONCLUSIONS: The LeVe CPAP system was the most used CPAP device during the pandemic, bringing the hospital's number of available HFNO/CPAP devices from two to 14. They were a critical resource for providing respiratory support to the sickest group of patients when no alternative devices were available. The devices appear to be safe and well-tolerated with no serious adverse events recorded. This study is unable to assess the efficacy of the LeVe CPAP System; therefore, formal comparative studies are required to inform further use.

Determining Phase Separation Dynamics with an Automated Image Processing Algorithm.

The problems of extracting products efficiently from reaction workups are often overlooked. Issues such as emulsions and rag layer formation can cause long separation times and slow production, thus resulting in manufacturing inefficiencies. To better understand science within this area and to support process development, an image processing methodology has been developed that can automatically track the interface between liquid-liquid phases and provide a quantitative measure of the separation rate of two immiscible liquids. The algorithm is automated and has been successfully applied to 29 cases. Its robustness has been demonstrated with a variety of different liquid mixtures that exhibit a wide range of separation behavior-making such an algorithm suited to high-throughput experimentation. The information gathered from applying the algorithm shows how issues resulting from poor separations can be detected early in process development.

Polymer-Induced Drag Reduction in Dilute Newtonian and Semi-Dilute Non-Newtonian Fluids: An Assessment of the Double-Gap Concentric Cylinder Method.

Polymer-induced drag reduction (DR) in fluids was studied using a rotational rheometer with double-gap concentric cylinder geometry. Although both polymers (polyacrylamide (PAM) and 2-acrylamido-2-methylpropane sulfonic acid (SPAM)) had molecular weights of several MDa, the contrasting polymer charge, nonionic and anionic, led to different polymer overlap concentrations (c*), PAM ≫ SPAM, and fluid rheology, with PAM fluids mostly Newtonian and SPAM fluids non-Newtonian (shear-thinning). Based on these differences, it was important to account for the infinite shear viscosity and normalize the polymer concentration by the intrinsic concentration (c int) so that the DR performance of the two polymer fluids could be accurately compared. Both polymers induced DR, and the maximum DR by SPAM (DR% = 28) was slightly higher than that by PAM (DR% = 22) when Re p ∼ 1700. For PAM, the loss of DR with time diminished at higher polymer concentrations (≥100 ppm, at Re p = 3149) but was found to be sensitive to high Re p, with polymer chain scission the likely cause of the reduced performance. For the semi-dilute SPAM fluids, the shear stability contrasted that of PAM, showing negligible dependence on the polymer concentration and Re p. The apparent rapid loss of DR was predominantly attributed to a time-dependent effect and not polymer degradation. In pipe flow, the maximum DR for SPAM was higher than that measured by rheometry and was attributed to differences in the flow conditions. However, changes in the normalized DR/c with polymer concentration were found to be consistent between the two flow geometries. Furthermore, the high fluid stresses in pipe flow (at high Re p) led to drag reduction losses consistent with PAM, as the time-dependent effect was not seen.

A Numerical Model for Investigating the Effect of Viscoelasticity on the Partial Slip Solution.

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Molecular epidemiology and mortality of group B streptococcal meningitis and infant sepsis in the Netherlands: a 30-year nationwide surveillance study.

BACKGROUND: Streptococcus agalactiae (group B streptococcus) causes invasive disease in all age groups. In the Netherlands, the incidence of group B streptococcal sepsis in early infancy is increasing because of a specific genetic subtype, clonal complex (CC) 17-A1. We assessed the molecular epidemiology, incidence, and mortality of group B streptococcal meningitis in the Netherlands over 30 years. METHODS: We used nationwide surveillance data from Jan 1, 1987, to Dec 31, 2016, on all group B streptococcal meningitis and sepsis cases. The surveillance database of the Netherlands Reference Laboratory for Bacterial Meningitis-which receives approximately 90% of cerebrospinal fluid isolates from all patients with bacterial meningitis in the Netherlands-was the data source for the study. All patients with group B streptococcus-positive cerebrospinal fluid cultures (meningitis) and infants (0-89 days) with group B streptococcus-positive blood cultures (sepsis) were included. Patients with missing date of birth were excluded. Multi-locus sequence typing and clade profiles were extracted from whole genome sequences. Serotyping was done by latex agglutination and genome sequencing. Survival data was obtained through Municipal Personal Records. FINDINGS: 1501 episodes in 1490 patients were identified: 626 meningitis cases (in patients of all ages) and 875 sepsis cases (in patients aged 0-89 days). Mean annual group B streptococcal meningitis incidence was 1·32 per 1 000 000 population. CC17-A1 caused 16 (5%) of 307 meningitis cases in the first half of the study and 77 (26%) of 296 meningitis cases in the second half of the observation period (p<0·0001). Because of a simultaneous decline in CC19, the overall meningitis incidence remained stable. 27 (8%) of 323 patients with meningitis younger than 3 months died and 14 (21%) of 66 patients older than 3 months died. Patients older than 65 years with sequence type (ST) 24 disease were independently associated with death. Serotype III and ST17 were associated with meningitis in early infancy, serotype III remained associated with meningitis in children younger than 3 months after correcting for ST17 (odds ratio 3·71, 95%CI 2·75-5·01). Serotype Ia, Ib, II, III, and V accounted for 98% of the meningitis cases in patients younger than 3 months and 92% cases in patients older than 3 months. INTERPRETATION: CC17-A1 is an increasing cause of group B streptococcal meningitis in all age groups. A pentavalent polysaccharide vaccine would cover most meningitis cases. FUNDING: Netherlands Organization for Health Research and Development and Amsterdam University Medical Centres.