Production of laminar extrudates containing particles of a model drug processed by supercritical fluids

Tese de doutoramento, Farmácia (Tecnologia Farmacêutica), Universidade de Lisboa, Faculdade de Farmácia, 2015The aim of this work was to test the hypothesis that laminar extrudates and co-extrudates, containing particles of drugs processed by supercritical fluids, can be manufactured at room temperature and in the absence of solvents, to deliver drugs by the oral or transdermal routes of administration. Particles of coumarin (drug) were manufactured by Rapid Expansion of Supercritical Solutions (RESS), which is a supercritical fluid micronization technique, using both a discontinuous and a continuous mode of operation. The manufactured particles of coumarin obtained from different RESS experiments, in which there were tested different experimental conditions, presented reduced sizes (between 20-40 μm, mean values) and similar properties in terms of morphology, surface area, thermal behavior, amorphous and crystalline contents, density and porosity. It was observed that specific experimental conditions of the RESS influenced the size of the manufactured drug particles, namely the pre-expansion pressure, the initial amount of solute, and the post-expansion pressure, amongst others. In parallell, several excipients and different formulations were developed and tested in order to manufacture extrudates with a laminar shape, at room temperature, and without including solvents in the formulations. The lipid-based materials were the excipients that better contributed for the aim of the study, as the formulations with these excipients in high proportions presented suitable physical and mechanical properties and, in consequence, a satisfactory quality. After identifying the best formulation, the extrusion processing parameters and their influence in the properties of the manufactured extrudates, namely the extrusion rate, were properly studied. Additionally, for each extrudate, there were analyzed the dissolution profiles, the thermal behaviors of the raw materials before extruding and of the extrudates after extrusion and over the storage period, as well as the evolution of the density, of the porosity and of the mechanical properties of the extrudates such as the bending strength, the deformation, the stiffness, and the elasticity (Young’s modulus). It was studied the release of the drug from extrudates containing particles of drugs with different sizes in order to assess the impact of the particle size of the drug on its release from the extrudates previously manufactured. It was concluded that the manufacture of extrudates at room temperature and without including solvents in the formulation is a promising technology for the manufacture of new pharmaceutical dosage forms. All the analysis performed both to the starting materials and to the obtained extrudates showed that after extrusion occurs an aging phenomenon of the extrudates, which is visible by the evident changes in their physical and mechanical properties over storage. This phenomenon is similar to the previously observed and described for the glycerides and triglycerides that mainly compose the lipid-based excipients selected for this study. The formulations composed by different excipients originated extrudates with different properties such as the mechanical properties. Also, the bending strength, the stiffness, the deformation, the elasticity, the density and the porosity changed over time, and the observed changes were related to the composition of the formulations and of the extrusion processing conditions. It was observed that the properties of the extrudates, namely their physical and mechanical properties, needed to be stabilized over time in order to maintain unaffected the release of the drug performance expected for certain drug and extrudate. Additionally, the extrudates including particles of drugs with smaller sizes presented higher release rates when compared with particles with higher dimensions. The formulations and the components selected for the manufacture of extrudates at room temperature and in the absence of solvents were in the majority composed by lipid-based materials, which can sustain the release of the drug. Therefore, it was concluded that the release rate of a certain drug can be modified by changing the composition of the formulatons and/or by changing the size of the particles of drug. The entire approach for the formulation development and for the study of the extrusion process and of the properties of the extrudates was replicated for the development of the laminar co-extrudates (with two or three layers). The properties and results obtained were similar to those observed for the extrudates with a single layer. The particles of coumarin micronized by RESS were included in laminar extrudates manufactured without changing the temperature during processing and avoiding the inclusion of solvents in the formulation. The release of coumarin from these extrudates was assessed and it was concluded that this pharmaceutical dosage form could successfully transport and release coumarin. Those laminar extrudates were also tested for its ability in delivering coumarin obtained by RESS and levothyroxine by both the oral and the transdermal routes of administration. The particles of both drugs, in separate, were included in formulations of extrudates and its in-vitro release, ex-vivo permeation and in-vivo absorption / permeation were properly assessed. Several portions of extrudates containing coumarin or levothyroxine were placed in the donor compartments of diffusion cells (Franz cells) containing a barrier composed by human skin (ex-vivo experiment) and it was observed that both drugs were successfully released and permeated through the skin. Also, several portions of extrudates containing levothyroxine were delivered to Wistar rats by both routes of administration (oral and transdermal) and it was observed that levothyroxine was respectively absorbed and permeated, being detected in the blood mainstream of the mice. All the findings described in this work allowed to conclude that the hypothesis was valid and that it is possible to manufacture extrudates and co-extrudates at room temperature, without including solvents containing particles of a drug manufactured by supercritical fluids.Fundação para a Ciência e a Tecnologia (FCT), SFRH/BD/39853/200

Ambidextrous leadership, paradox and contingency: evidence from Angola

The study departs from two assumptions. First, it considers that organizations, their leaders and the HRM function are inherently paradoxical and that, in that sense, dealing with paradox is a necessary component of the leadership process which requires ambidexterity capabilities. Second, it explores whether the paradoxes of leadership may manifest differently in different contexts. We explore the emergence of paradox in the leadership of Angolan organizations. Angola is an economy transitioning from a centrally planned to a market mode, and this makes it a rich site for understanding the specificities of ambidextrous paradoxical processes in an under-researched, ‘rest of the world’, context. The findings of our inductive study led to the emergence of four interrelated paradoxes and highlight the importance of ambidextrous paradoxical work as a HRM contingency.N/

merlin, an improved framework for the reconstruction of high-quality genome-scale metabolic models

Genome-scale metabolic models have been recognised as useful tools for better understanding living organisms metabolism. merlin (https://www.merlin-sysbio.org/) is an open-source and user-friendly resource that hastens the models reconstruction process, conjugating manual and automatic procedures, while leveraging the user's expertise with a curation-oriented graphical interface. An updated and redesigned version of merlin is herein presented. Since 2015, several features have been implemented in merlin, along with deep changes in the software architecture, operational flow, and graphical interface. The current version (4.0) includes the implementation of novel algorithms and third-party tools for genome functional annotation, draft assembly, model refinement, and curation. Such updates increased the user base, resulting in multiple published works, including genome metabolic (re-)annotations and model reconstructions of multiple (lower and higher) eukaryotes and prokaryotes. merlin version 4.0 is the only tool able to perform template based and de novo draft reconstructions, while achieving competitive performance compared to state-of-the art tools both for well and less-studied organisms.Centre of Biological Engineering (CEB, UMinho); Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit; this work is a result of the project 22231/01/SAICT/2016: Biodata.pt Infraestrutura Portuguesa de Dados Biologicos, supported by the ´ PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); FCT for providing PhD scholarships [DFA/BD/08789/2021 J.C, DFA/BD/8076/2020 E.C., SFRH/BD/139198/2018 to F.C., SFRH/BD/131916/2017 R. Rodrigues]; FCT for the Assistant Research contract of Oscar Dias obtained under CEEC Individual 2018.info:eu-repo/semantics/publishedVersio

Towards a multivariate analysis of genome-scale metabolic models derived from the BiGG models database

First Online: 28 August 2021Genome-Scale metabolic models (GEMs) are a relevant tool in systems biology for in silico strain optimisation and drug discovery. An easier way to reconstruct a model is to use available GEMs as templates to create the initial draft, which can be curated up until a simulation-ready model is obtained. This approach is implemented in merlin's BiGG Integration Tool, which reconstructs models from existing GEMs present in the BiGG Models database. This study aims to assess draft models generated using models from BiGG as templates for three distinct organisms, namely, Streptococcus thermophilus, Xylella fastidiosa and Mycobacterium tuberculosis. Several draft models were reconstructed using the BiGG Integration Tool and different templates (all, selected and random). The variability of the models was assessed using the reactions and metabolic functions associated with the model's genes. This analysis showed that, even though the models shared a significant portion of reactions and metabolic functions, models from different organisms are still differentiated. Moreover, there also seems to be variability among the templates used to generate the draft models to a lower extent. This study concluded that the BiGG Integration Tool provides a fast and reliable alternative for draft reconstruction for bacteria.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. A. Oliveira (DFA/BD/10205/2020), E. Cunha (DFA/BD/8076/2020), F. Cruz (SFRH /BD/139198/2018), J. Sequeira (SFRH/BD/147271/2019), and M. Sampaio (SFRH/BD/144643/2019) hold a doctoral fellowship provided by the FCT. Oscar Dias acknowledge FCT for the Assistant Research contract obtained under CEEC Individual 2018.info:eu-repo/semantics/publishedVersio

Novo protocolo utilizando ocitocina para induzir a ejaculação em garanhão penectomizado

Background: Several reproductive diseases can prevent ejaculation by the traditional method of collection. Neoplasias as squamous cell carcinoma is the most common tumor of the external genitalia of horses and its lesions usually prevent copulation. The pharmacological induction of ejaculation is an important alternative technique to obtain and preserve the genetic material of stallions incapable of ejaculating by traditional methods of semen collection. However, the protocols currently used have shown questionable results and new protocols are needed in order to increase the success rates. The aim of this study is to report the success of a new protocol in inducing ejaculation when oral imipramine and intravenous oxytocin and detomidine were administrated in a Crioulo stallion.Case: A 9-year-old Crioulo stallion was admitted at the Veterinary Hospital of the São Paulo State University, FMVZUNESP, Botucatu, Brazil, with a history of a mass located on the glans and body of the penis. The histopathological exam confirmed the diagnostic of Squamous cell carcinoma and penectomy was performed. After 10 days of surgery the stallion was submitted to 5 different protocols with 3 days interval between the follow protocols: Imipramine+Xylazine; Imipramine+ Xylazine+Oxytocin; Imipramine+Detomidine and Imipramine+Detomidine+Oxytocin.Discussion: The traditional protocol of pharmacologically-induced ejaculation with imipramine hydrochloride (3 mg/kg/v.o) and xylazine hydrochloride (0.66 mg/kg/iv) was not successful even when oxytocin (20 UI/iv) was added to this protocol. Administration of imipramine hydrochloride (3 mg/kg/v.o) two hours prior to administration of detomidine hydrochloride (0.02 mg/kg/i.v) also did not result in ejaculation. However, administration of imipramine hydrochloride (3 mg/kg/v.o) 2 h prior to administration of detomidine hydrochloride (0.02 mg/kg/i.v) associated with oxytocin (20 U.I/i.v) resulted in ejaculation. The stallion was submitted to three seminal collections with a three-day interval between administration of the protocol and ejaculated in all the attempts after approximately 5 min of detomidine and oxytocin injection, presenting mean values of 50 mL of total volume (TV) and concentration of 80x106 spermatozoa/mL. The VT was higher and concentration was lower when compared to ejaculates obtained by pharmacological induction in previous studies, probably due to daily stimulation with estrus mare to induce penile exposure in order to allow antisepsis of the surgical wound. Thus, it is believed that the large amount of total volume of this stallion is due to the high production of gel by the accessory sex glands, with consequent reduction of ejaculate concentration. The sperm kinetics were evaluated by the computerized method CASA (HTMA-IVOS-12) with total motility (MT) of 84% and progressive (MP) of 38%, with 70% of rapid spermatozoa (RAP), being considered normal to the equine specie and similar to those observed by other authors in pharmacolocally-induced ejaculates. Post-thaw sperm kinetics presented 42% of MT, 21% of MP and 28% of RAP probably due to an intrinsic sensitivity of the stallion to the freezing process. Thus, this report concludes that the protocol associating imipramine, detomidine and oxytocin was efficient in the pharmacological induction of ejaculation, presenting normal and characteristic sperm parameters of the specie. Fresh and refrigerated semen presented good parameters for use in conventional artificial inseminations while frozen semen is indicated for deep horn inseminations or for use in intracytoplasmic sperm injection (ICSI) programs

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (FST coefficients) to the present database ranged from FST = 0.0016 between Macapá and Belém to FST = 0.0036 between Macapá and the Iberian Peninsula

Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

The observation of Higgs boson production in association with a top quark pair ( tt¯H ), based on the analysis of proton–proton collision data at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider, is presented. Using data corresponding to integrated luminosities of up to 79.8 fb −1 , and considering Higgs boson decays into bb¯ , WW⁎ , τ+τ− , γγ , and ZZ⁎ , the observed significance is 5.8 standard deviations, compared to an expectation of 4.9 standard deviations. Combined with the tt¯H searches using a dataset corresponding to integrated luminosities of 4.5 fb −1 at 7 TeV and 20.3 fb −1 at 8 TeV, the observed (expected) significance is 6.3 (5.1) standard deviations. Assuming Standard Model branching fractions, the total tt¯H production cross section at 13 TeV is measured to be 670 ± 90 (stat.) −100+110 (syst.) fb, in agreement with the Standard Model prediction.Peer Reviewe

Measurement of photon–jet transverse momentum correlations in 5.02 TeV Pb + Pb and pppp collisions with ATLAS

Jets created in association with a photon can be used as a calibrated probe to study energy loss in the medium created in nuclear collisions. Measurements of the transverse momentum balance between isolated photons and inclusive jets are presented using integrated luminosities of 0.49 nb$^{-1}$ of Pb+Pb collision data at $\sqrt{s_\mathrm{NN}}=5.02$ TeV and 25 pb$^{-1}$ of $pp$ collision data at $\sqrt{s}=5.02$ TeV recorded with the ATLAS detector at the LHC. Photons with transverse momentum $63.1 31.6$ GeV and pseudorapidity $\left|\eta^\mathrm{jet}\right| 7\pi/8$. Distributions of the per-photon jet yield as a function of $x_\mathrm{J\gamma}$, $(1/N_\gamma)(\mathrm{d}N/\mathrm{d}x_\mathrm{J\gamma})$, are corrected for detector effects via a two-dimensional unfolding procedure and reported at the particle level. In $pp$ collisions, the distributions are well described by Monte Carlo event generators. In Pb+Pb collisions, the $x_\mathrm{J\gamma}$ distribution is modified from that observed in $pp$ collisions with increasing centrality, consistent with the picture of parton energy loss in the hot nuclear medium. The data are compared with a suite of energy-loss models and calculations.Peer Reviewe