Magnetophoretic cell clarification

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004.Page 178 blank.Includes bibliographical references.(cont.) the feed fluid was achieved after one pass through the counter current system. In the second case, four permanent magnets were arranged in a quadrupole around a central column to create areas of high magnetic field at the column walls and areas of low magnetic field at the centerline, inducing non-magnetic particles to concentrate at the centerline, where they were removed through a coaxial central outlet tube at the top of the column. Depending on the flow rate, up to 99% of polystyrene beads of different sizes could be removed from the feed after one pass through the quadrupole system. The recovery efficiency decreased with increasing flow rate, i.e. with decreasing residence time in the device. E. coli cells were able to be removed with separation efficiencies as high as 95% at much higher flow rates due to the formation of [approximately]12 micron aggregates in the presence of the magnetic nanoparticles; these large aggregates experienced enhanced magnetic forces over individually-dispersed cells and could be recovered more effectively. The governing equations for magnetophoretic clarification were applied to the quadrupole configuration to predict particle trajectories through the column and to predict the separation efficiency under different flow conditions, which showed a good match to the experimental results. It was also shown that axial magnetic field gradients near the entrance region acted effectively as a barrier to entry of particles in the slow moving regions near the walls; this retardation of their axial movement provided a longer residence time for the particles that allowed them to be moved more efficiently to the centerline ...A new approach for the removal of micron-sized particles from aqueous suspensions was developed and applied to the problem of cell clarification from raw fermentation broth. The concepts of magnetophoretic separation were exploited to take advantage of the force that acts on a non-magnetic particle when it is immersed in a magnetic fluid (ferrofluid) that is subjected to a non-uniform magnetic field. The magnetic "pressure" difference across the non-magnetic particle owing to the magnetization of the surrounding magnetic fluid forces the particles away from areas of high magnetic field strength and into areas of low magnetic field strength. This force is proportional to the volume of the non-magnetic particles, and is therefore stronger for larger particles. In this way, non-magnetic particles can be focused and moved out of the bulk fluid by applying a non-uniform magnetic field to the system, leading to magnetophoretic clarification. The magnetic fluid used in this work was composed of magnetite nanoparticles coated with a poly(acrylic acid)-poly(ethylene oxide)-poly(propylene oxide) graft copolymer layer that stabilized the nanoparticles in water and prevented their aggregation. The magnetic nanoparticles were approximately 32 nm in diameter, with the magnetite core itself being approximately 8 nm in diameter. Magnetophoretic clarification was investigated using two different flow configurations. In the first case, the particle-laden magnetic fluid was pumped through a flow tube while a series of magnets around the tube moved counter to the direction of the feed flow; the non-magnetic particles in the feed were captured and effectively removed from the bulk fluid by the moving magnets. A removal efficiency of 95% of E. coli cells fromby Sonja Ann Sharpe.Ph.D

3D printing of tablets using inkjet with UV photoinitiation

Additive manufacturing (AM) offers significant potential benefits in the field of drug delivery and pharmaceutical/medical device manufacture. Of AM processes, 3D inkjet printing enables precise deposition of a formulation, whilst offering the potential for significant scale up or scale out as a manufacturing platform. This work hypothesizes that suitable solvent based ink formulations can be developed that allow the production of solid dosage forms that meet the standards required for pharmaceutical tablets, whilst offering a platform for flexible and personalised manufacture. We demonstrate this using piezo-activated inkjetting to 3D print ropinirole hydrochloride. The tablets produced consist of a cross-linked poly(ethylene glycol diacrylate) (PEGDA) hydrogel matrix containing the drug, photoinitiated in a low oxygen environment using an aqueous solution of Irgacure 2959. At a Ropinirole HCl loading of 0.41 mg, drug release from the tablet is shown to be Fickian. Raman and IR spectroscopy indicate a high degree of cross-linking and formation of an amorphous solid dispersion. This is the first publication of a UV inkjet 3D printed tablet. Consequently, this work opens the possibility for the translation of scalable, high precision and bespoke ink-jet based additive manufacturing to the pharmaceutical sector

3D extrusion printing of high drug loading immediate release paracetamol tablets

The manufacture of immediate release high drug loading paracetamol oral tablets was achieved using an extrusion based 3D printer from a premixed water based paste formulation. The 3D printed tablets demonstrate that a very high drug (paracetamol) loading formulation (80% w/w) can be printed as an acceptable tablet using a method suitable for personalisation and distributed manufacture. Paracetamol is an example of a drug whose physical form can present challenges to traditional powder compression tableting. Printing avoids these issues and facilitates the relatively high drug loading. The 3D printed tablets were evaluated for physical and mechanical properties including weight variation, friability, breaking force, disintegration time, and dimensions and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia (USP). X-Ray Powder Diffraction (XRPD) was used to identify the physical form of the active. Additionally, XRPD, Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC) were used to assess possible drug-excipient interactions. The 3D printed tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed a profile characteristic of the immediate release profile as intended based upon the active/excipient ratio used with disintegration in less than 60 seconds and release of most of the drug within 5 minutes. The results demonstrate the capability of 3D extrusion based printing to produce acceptable high-drug loading tablets from approved materials that comply with current USP standards

Personalized versus standard cognitive behavioral therapy for fear of cancer recurrence, depressive symptoms or cancer-related fatigue in cancer survivors:study protocol of a randomized controlled trial (MATCH-study)

Abstract Background Fear of cancer recurrence, depressive symptoms, and cancer-related fatigue are prevalent symptoms among cancer survivors, adversely affecting patients’ quality of life and daily functioning. Effect sizes of interventions targeting these symptoms are mostly small to medium. Personalizing treatment is assumed to improve efficacy. However, thus far the empirical support for this approach is lacking. The aim of this study is to investigate if systematically personalized cognitive behavioral therapy is more efficacious than standard cognitive behavioral therapy in cancer survivors with moderate to severe fear of cancer recurrence, depressive symptoms, and/or cancer-related fatigue. Methods The study is designed as a non-blinded, multicenter randomized controlled trial with two treatment arms (ratio 1:1): (a) systematically personalized cognitive behavioral therapy and (b) standard cognitive behavioral therapy. In the standard treatment arm, patients receive an evidence-based diagnosis-specific treatment protocol for fear of cancer recurrence, depressive symptoms, or cancer-related fatigue. In the second arm, treatment is personalized on four dimensions: (a) the allocation of treatment modules based on ecological momentary assessments, (b) treatment delivery, (c) patients’ needs regarding the symptom for which they want to receive treatment, and (d) treatment duration. In total, 190 cancer survivors who experience one or more of the targeted symptoms and ended their medical treatment with curative intent at least 6 months to a maximum of 5 years ago will be included. Primary outcome is limitations in daily functioning. Secondary outcomes are level of fear of cancer recurrence, depressive symptoms, fatigue severity, quality of life, goal attainment, therapist time, and drop-out rates. Participants are assessed at baseline (T0), and after 6 months (T1) and 12 months (T2). Discussion To our knowledge, this is the first randomized controlled trial comparing the efficacy of personalized cognitive behavioral therapy to standard cognitive behavioral therapy in cancer survivors. The study has several innovative characteristics, among which is the personalization of interventions on several dimensions. If proven effective, the results of this study provide a first step in developing an evidence-based framework for personalizing therapies in a systematic and replicable way. Trial registration The Dutch Trial Register (NTR) NL7481 (NTR7723). Registered on 24 January 2019

Extrusion 3D printing of paracetamol tablets from a single formulation with tunable release profiles through control of tablet geometry

An extrusion based 3D printer was used to fabricate paracetamol tablets with different geometries (mesh, ring, and solid) from a single paste-based formulation formed from standard pharmaceutical ingredients. The tablets demonstrate that tunable drug release profiles can be achieved from this single formulation even with high drug loading (>80% w/w). The tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed well-defined release profiles (from immediate to sustained release) controlled by their different geometries. The dissolution results showed dependency of drug release on the surface area/volume (SA/V) ratio and the SA of the different tablets. The tablets with larger SA/V ratios and SA had faster drug release. The 3D printed tablets were also evaluated for physical and mechanical properties including tablet dimension, drug content, weight variation, breaking force and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia. X-Ray Powder Diffraction, Differential Scanning Calorimetry, and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy were used to identify the physical form of the active and to assess possible drug-excipient interactions. These data again showed that the tablets meet USP requirement. These results clearly demonstrate the potential of 3D printing to create unique pharmaceutical manufacturing, and potentially clinical, opportunities. The ability to use a single unmodified formulation to achieve defined release profiles could allow, for example, relatively straightforward personalization of medicines for individuals with different metabolism rates for certain drugs and hence could offer significant development and clinical opportunities

Extrusion 3D printing of paracetamol tablets from a single formulation with tunable release profiles through control of tablet geometry

An extrusion based 3D printer was used to fabricate paracetamol tablets with different geometries (mesh, ring, and solid) from a single paste-based formulation formed from standard pharmaceutical ingredients. The tablets demonstrate that tunable drug release profiles can be achieved from this single formulation even with high drug loading (>80% w/w). The tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed well-defined release profiles (from immediate to sustained release) controlled by their different geometries. The dissolution results showed dependency of drug release on the surface area/volume (SA/V) ratio and the SA of the different tablets. The tablets with larger SA/V ratios and SA had faster drug release. The 3D printed tablets were also evaluated for physical and mechanical properties including tablet dimension, drug content, weight variation, breaking force and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia. X-Ray Powder Diffraction, Differential Scanning Calorimetry, and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy were used to identify the physical form of the active and to assess possible drug-excipient interactions. These data again showed that the tablets meet USP requirement. These results clearly demonstrate the potential of 3D printing to create unique pharmaceutical manufacturing, and potentially clinical, opportunities. The ability to use a single unmodified formulation to achieve defined release profiles could allow, for example, relatively straightforward personalization of medicines for individuals with different metabolism rates for certain drugs and hence could offer significant development and clinical opportunities

“Pork pies and vindaloos”: learning for cosmopolitan citizenship

This paper examines Audrey Osler and Hugh Starkey’s 2003 article on cosmopolitan citizenship 14 years after its publication. Since its publication, young people’s disconnection from political life has increasingly become a cause for concern for most, if not all, Western democracies. Specifically, this article examines the implications for young people’s political life in Leicester following a period of local, regional and national political changes. The study has shown how some South Asian young people occupy “outsiders-within” status in Leicester’s “common culture” (and all the sub-cultures that exist within it) and see their ethnic communities from a range of voyeuristic positions. Young South Asian participants in the study have not distanced themselves from the South Asian community entirely, but the way participants have approached narrating their self-identities has not necessarily been forged in, or determined upon, how “Indian” or “Pakistani” identities are conceived by the common culture. Consequently, two questions arise. Firstly, what is the impact of developing cosmopolitan citizenship among young people forging new types of ethnic identities in Leicester? Secondly, what types of educational approaches (formal and informal) would be important to help strengthen young people’s political engagement? The paper concludes that the ongoing challenge for educators is to strengthen mutual understanding between students from different communities and backgrounds by drawing on their lived experience within the caveat of promoting cosmopolitan citizenship

B7-H1-Deficiency Enhances the Potential of Tolerogenic Dendritic Cells by Activating CD1d-Restricted Type II NKT Cells

Background: Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4+ T cell and NKT cell responses. Methodology/Principal Findings: Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1, CD274) on semimature DC that were generated from bone marrow (BM) cells of B7-H12/2 mice and applied to the model of Experimental Autoimmune Encephalomyelitis (EAE). Injections of B7-H1-deficient DC showed increased EAE protection as compared to wild type (WT)-DC. Injections of B7-H12/2 TNF-DC induced higher release of peptide-specific IL-10 and IL-13 after restimulation in vitro together with elevated serum cytokines IL-4 and IL-13 produced by NKT cells, and reduced IL-17 and IFN-c production in the CNS. Experiments in CD1d2/2 and Ja2812/2 mice as well as with type I and II NKT cell lines indicated that only type II NKT cells but not type I NKT cells (invariant NKT cells) could be stimulated by an endogenous CD1d-ligand on DC and were responsible for the increased serum cytokine production in the absence of B7-H1. Conclusions/Significance: Together, our data indicate that BM-DC express an endogenous CD1d ligand and B7-H1 to ihibit type II but not type I NKT cells. In the absence of B7-H1 on these DC their tolerogenic potential to stimulate tolerogenic CD4+ and NKT cell responses is enhanced

Analysis of the African coelacanth genome sheds light on tetrapod evolution

It was a zoological sensation when a living specimen of the coelacanth was first discovered in 1938, as this lineage of lobe-finned fish was thought to have gone extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features . Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain, and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues demonstrate the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution