Single-phase laminar flow heat transfer from confined electron beam enhanced surfaces

An experimental investigation of the thermal-hydraulic characteristics for single-phase flow through three electron beam enhanced structures was conducted with water at mass flow rates from 0.005 kg/s to 0.045 kg/s. The structures featured copper heat transfer surfaces, approximately 28 mm wide and 32 mm long in the flow direction, with complex three-dimensional (3D) electron beam manufactured pyramid-like structures. The channel height varied depending on the height of the protrusions and the tip clearance was maintained at 0.1-0.3 mm. The average protrusion densities for the three samples S1, S2, and S3 were 13, 11, and 25 per cm2 with protrusion heights of 2.5, 2.8, and 1.6 mm, respectively. The data gathered were compared to those for a smooth channel surface operating under similar conditions. The results show an increase up to approximately three times for the average Nusselt number compared with the smooth surface. This is attributed to the surface irregularities of the enhanced surfaces, which not only increase the heat transfer area but also improve mixing, disturb the thermal and velocity boundary layers, and reduce thermal resistance. The increase in heat transfer with the enhanced surfaces was accompanied by an increase of pressure drop, which has to be considered in design.The authors would like to acknowledge Dr Anita Buxton and Dr Bruce Dance of TWI for their contribution to this project and also EPSRC and TSB for funding the EngD programme and sponsoring the ASTIA collaborative research project that helped to develop the Electron Beam enhanced surfaces respectively

STEATOSE HEPATIQUE AIGUE GRAVIDIQUE A PROPOS DE QUATRE CAS

Introduction : La stéatose hépatique aiguë gravidique (SHAG) est une maladie hépatique rare, responsable d’une insuffisance hépatocellulaire aiguë, d’un trouble de l’hémostase et d’une insuffisance rénale .C’est une urgence médicale et obstétricale mettant en jeu le pronostic maternel et foetal. L’objectif de notre travail est de décrire les caractéristiques cliniques, détailler la prise en charge thérapeutique et dégager les éléments de mauvais pronostic maternel de la SHAG.Observations : Nous rapportons quatre observations de SHAG, l age gestationnel de nos patientes était réparti entre 32 et 35 semaines. Deux entre elles étaient des multipares, avec des grossesses antérieures normales. Deux de nos patientes avaient une HTAG dont l’une a présenté initialement une pré éclampsie. Les signes digestifs sont retrouvés dans les quatre observations. Trois de nos patientes ont présenté un ictère entre quatre et dix jours avant l’accouchement tandis qu’une seule l’a présenté en post partum immédiat. L’hypoglycémie a été présente dans les trois observations. Deux de nos patientes avaient un taux de prothrombine inférieur à 50% et une patiente avait présenté un trouble sévère d’hémostase ayant nécessité une transfusion sanguine. L’accouchement a eu lieu par voie basse dans un cas et par césarienne urgente dans trois cas, en ce qui concerne le pronostic on a noté un décès dans un tableau de défaillance hépatorénale et d’hémorragie gastrointestinale, et une rémission complète pour les trois autres patientes.Conclusion : La SHAG reste une pathologie grave. le diagnostic de la phase préictérique et l’évacuation utérine précoce constituent les seuls éléments pouvant améliorer sensiblement son pronostic

Quaternization of Vinyl/Alkynyl Pyridine Enables Ultrafast Cysteine-Selective Protein Modification and Charge Modulation.

Quaternized vinyl- and alkynyl-pyridine reagents were shown to react in an ultrafast and selective manner with several cysteine-tagged proteins at near-stoichiometric quantities. We have demonstrated that this method can effectively create a homogenous antibody-drug conjugate that features a precise drug-to-antibody ratio of 2, which was stable in human plasma and retained its specificity towards Her2+ cells. Finally, the developed warhead introduces a +1 charge to the overall net charge of the protein, which enabled us to show that the electrophoretic mobility of the protein may be tuned through the simple attachment of a quaternized vinyl pyridinium reagent at the cysteine residues. We anticipate the generalized use of quaternized vinyl- and alkynyl-pyridine reagents not only for bioconjugation, but also as warheads for covalent inhibition and as tools to profile cysteine reactivity

Prise en charge du couple mère enfant de la varicelle pendant la grossesse

La varicelle est une maladie généralement bénigne chez l’enfant, cependant l’atteinte de l’adulte est potentiellement grave et son association à la grossesse expose la mère et le nouveau né à des risques de complications plus redoutables.La prise en charge multidisciplinaire associant obstétricien, biologiste et pédiatre est indispensable pour limiter les effets délétères de l’infection par la varicelle pendant la grossesse.Nous rapportons dans cet article les approches thérapeutiques actuellement proposées pour la prise en charge anté et péripartum du couple mère-enfant en cas d’infection par la varicelle pendant la grossesse et nous proposons des conduites visant à atténuer les complications maternelles

Recent advances on smart glycoconjugate vaccines in infections and cancer

Vaccination is one of the greatest achievements in biomedical research preventing death and morbidity in many infectious diseases through the induction of pathogen-specific humoral and cellular immune responses. Currently, no effective vaccines are available for pathogens with a highly variable antigenic load, such as the human immunodeficiency virus or to induce cellular T-cell immunity in the fight against cancer. The recent SARS-CoV-2 outbreak has reinforced the relevance of designing smart therapeutic vaccine modalities to ensure public health. Indeed, academic and private companies have ongoing joint efforts to develop novel vaccine prototypes for this virus. Many pathogens are covered by a dense glycan-coat, which form an attractive target for vaccine development. Moreover, many tumor types are characterized by altered glycosylation profiles that are known as “tumor-associated carbohydrate antigens”. Unfortunately, glycans do not provoke a vigorous immune response and generally serve as T-cell-independent antigens, not eliciting protective immunoglobulin G responses nor inducing immunological memory. A close and continuous crosstalk between glycochemists and glycoimmunologists is essential for the successful development of efficient immune modulators. It is clear that this is a key point for the discovery of novel approaches, which could significantly improve our understanding of the immune system. In this review, we discuss the latest advancements in development of vaccines against glycan epitopes to gain selective immune responses and to provide an overview on the role of different immunogenic constructs in improving glycovaccine efficacy

Emerging glyco-based strategies to steer immune responses

Glycan structures are common posttranslational modifications of proteins, which serve multiple important structural roles (for instance in protein folding), but also are crucial participants in cell-cell communications and in the regulation of immune responses. Through the interaction with glycan-binding receptors, glycans are able to affect the activation status of antigen-presenting cells, leading either to induction of pro-inflammatory responses or to suppression of immunity and instigation of immune tolerance. This unique feature of glycans has attracted the interest and spurred collaborations of glyco-chemists and glyco-immunologists to develop glycan-based tools as potential therapeutic approaches in the fight against diseases such as cancer and autoimmune conditions. In this review, we highlight emerging advances in this field, and in particular, we discuss on how glycan-modified conjugates or glycoengineered cells can be employed as targeting devices to direct tumor antigens to lectin receptors on antigen-presenting cells, like dendritic cells. In addition, we address how glycan-based nanoparticles can act as delivery platforms to enhance immune responses. Finally, we discuss some of the latest developments in glycan-based therapies, including chimeric antigen receptor (CAR)-T cells to achieve targeting of tumor-associated glycan-specific epitopes, as well as the use of glycan moieties to suppress ongoing immune responses, especially in the context of autoimmunity

Recent advances on smart glycoconjugate vaccines in infections and cancer

Vaccination is one of the greatest achievements in biomedical research preventing death and morbidity in many infectious diseases through the induction of pathogen-specific humoral and cellular immune responses. Currently, no effective vaccines are available for pathogens with a highly variable antigenic load, such as the human immunodeficiency virus or to induce cellular T-cell immunity in the fight against cancer. The recent SARS-CoV-2 outbreak has reinforced the relevance of designing smart therapeutic vaccine modalities to ensure public health. Indeed, academic and private companies have ongoing joint efforts to develop novel vaccine prototypes for this virus. Many pathogens are covered by a dense glycan-coat, which form an attractive target for vaccine development. Moreover, many tumor types are characterized by altered glycosylation profiles that are known as “tumor-associated carbohydrate antigens”. Unfortunately, glycans do not provoke a vigorous immune response and generally serve as T-cell-independent antigens, not eliciting protective immunoglobulin G responses nor inducing immunological memory. A close and continuous crosstalk between glycochemists and glycoimmunologists is essential for the successful development of efficient immune modulators. It is clear that this is a key point for the discovery of novel approaches, which could significantly improve our understanding of the immune system. In this review, we discuss the latest advancements in development of vaccines against glycan epitopes to gain selective immune responses and to provide an overview on the role of different immunogenic constructs in improving glycovaccine efficacy