The indivisibility of the homogeneous Kn-free graphs

AbstractWe will prove that for each n ≥ 3 the homogeneous Kn-free graph Hn is indivisible. That means that for every partition of Hn into two classes R and B there is an isomorphic copy of Hn in R or in B. This extends a result of Komjáth and Rödl [Graphs Combin., 2 (1986), 55–60] who have shown that H3 is indivisible

Détection de l'adultération du beurre par la margarine

Une méthode analytique permettant de détecter l’adultération du beurre par la margarine a été développée. Elle est basée sur la détermination de la composition en acides gras et en stérols par chromatographie en phase gazeuse. Plusieurs niveaux d’adultération du beurre par la margarine (3, 5 et 10% p/p) ont été préparés puis analysés. Les résultats montrent que l’acide linoléique et les stérols permettent de détecter la margarine dans le beurre à un seuil de 3%

Préparation du fromage frais à partir du lait recombiné

Le but de cette étude a été d'évaluer les possibilités de préparation du fromage frais à partir du lait recombiné qui a été pasteurisé puis conservé pendant une nuit à 6°C pour faciliter la réhydratation. Le lait a été ensuite inoculé avec le levain constitué à parts égales de L. lactis subsp. lactis, L. lactis subsp. lactis var. diacetylactis et L. casei subsp casei à raison de 3% puis maintenu entre 30 et 37°C pour activer la fermentation. À pH 5,0 à 5,5, la présure a été ajoutée puis le moulage a été réalisé à température ambiante lorsque le pH a atteint une valeur comprise entre 4,3 .. 5,0. L'adoption de cette procédure normalisée de préparation du fromage frais a donné lieu à des produits de composition physico-chimique régulière et de qualité microbiologique satisfaisante. L'analyse sensorielle du fromage frais a montré que les produits élaborés à partir du lait recombiné uniquement (100%), ont été moins appréciés que ceux préparés à partir du lait recombiné additionné de 25 ou 50% de lait frais.Manufacture of fresh cheese from recombined milkThis study was carried out to evaluate the possibility of making fresh cheese from recombined milk. For this preparation, recombined milk was pasteurized and cooled overnight at 6°C to improve the powder rehydration. Then, milk was inoculated with 3% of a lactic starter composed of L.lactis subsp. lactis, L. lactis subsp.lactis var. diacetylactis and L. ca sei subsp. casei, and kept at 30 - 3TC to activate fermentation. At pH 5,0 - 5,5, the rennet was added and moulding was realized at ambient temperature when the pH reached a value of 4,3 to 5,0. Standardization of the processing gave fresh cheese with a regular chemical composition and a satisfactory microbiological quality. The sensory evaluation of fresh cheese showed that the products made with 100% recombined milk were less appreciated than those prepared from recombined milk added up with 20 to 25% fresh milk

Préparation du fromage frais à partir du lait recombiné

Le but de cette étude a été d'évaluer les possibilités de préparation du fromage frais à partir du lait recombiné qui a été pasteurisé puis conservé pendant une nuit à 6°C pour faciliter la réhydratation. Le lait a été ensuite inoculé avec le levain constitué à parts égales de L. lactis subsp. lactis, L. lactis subsp. lactis var. diacetylactis et L. casei subsp casei à raison de 3% puis maintenu entre 30 et 37°C pour activer la fermentation. À pH 5,0 à 5,5, la présure a été ajoutée puis le moulage a été réalisé à température ambiante lorsque le pH a atteint une valeur comprise entre 4,3 .. 5,0. L'adoption de cette procédure normalisée de préparation du fromage frais a donné lieu à des produits de composition physico-chimique régulière et de qualité microbiologique satisfaisante. L'analyse sensorielle du fromage frais a montré que les produits élaborés à partir du lait recombiné uniquement (100%), ont été moins appréciés que ceux préparés à partir du lait recombiné additionné de 25 ou 50% de lait frais.Manufacture of fresh cheese from recombined milkThis study was carried out to evaluate the possibility of making fresh cheese from recombined milk. For this preparation, recombined milk was pasteurized and cooled overnight at 6°C to improve the powder rehydration. Then, milk was inoculated with 3% of a lactic starter composed of L.lactis subsp. lactis, L. lactis subsp.lactis var. diacetylactis and L. ca sei subsp. casei, and kept at 30 - 3TC to activate fermentation. At pH 5,0 - 5,5, the rennet was added and moulding was realized at ambient temperature when the pH reached a value of 4,3 to 5,0. Standardization of the processing gave fresh cheese with a regular chemical composition and a satisfactory microbiological quality. The sensory evaluation of fresh cheese showed that the products made with 100% recombined milk were less appreciated than those prepared from recombined milk added up with 20 to 25% fresh milk

Diversifying Anaerobic Respiration Strategies to Compete in the Rhizosphere

The rhizosphere is the interface between plant roots and soil where intense, varied interactions between plants and microbes influence plants' health and growth through their influence on biochemical cycles, such as the carbon, nitrogen, and iron cycles. The rhizosphere is also a changing environment where oxygen can be rapidly limited and anaerobic zones can be established. Microorganisms successfully colonize the rhizosphere when they possess specific traits referred to as rhizosphere competence. Anaerobic respiration flexibility contributes to the rhizosphere competence of microbes. Indeed, a wide range of compounds that are available in the rhizosphere can serve as alternative terminal electron acceptors during anaerobic respiration such as nitrates, iron, carbon compounds, sulfur, metalloids, and radionuclides. In the presence of multiple terminal electron acceptors in a complex environment such as the rhizosphere and in the absence of O2, microorganisms will first use the most energetic option to sustain growth. Anaerobic respiration has been deeply studied, and the genes involved in anaerobic respiration have been identified. However, aqueous environment and paddy soils are the most studied environments for anaerobic respiration, even if we provide evidence in this review that anaerobic respiration also occurs in the plant rhizosphere. Indeed, we provide evidence by performing a BLAST analysis on metatranscriptomic data that genes involved in iron, sulfur, arsenate and selenate anaerobic respiration are expressed in the rhizosphere, underscoring that the rhizosphere environment is suitable for the establishment of anaerobic respiration. We thus focus this review on current research concerning the different types of anaerobic respiration that occur in the rhizosphere. We also discuss the flexibility of anaerobic respiration as a fundamental trait for the microbial colonization of roots, environmental and ecological adaptation, persistence and bioremediation in the rhizosphere. Anaerobic respiration appears to be a key process for the functioning of an ecosystem and interactions between plants and microbes

Ultraviolet disinfection robots to improve hospital cleaning: Real promise or just a gimmick?

The global COVID-19 pandemic due to the novel coronavirus SARS-CoV-2 has challenged the availability of traditional surface disinfectants. It has also stimulated the production of ultraviolet-disinfection robots by companies and institutions. These robots are increasingly advocated as a simple solution for the immediate disinfection of rooms and spaces of all surfaces in one process and as such they seem attractive to hospital management, also because of automation and apparent cost savings by reducing cleaning staff. Yet, there true potential in the hospital setting needs to be carefully evaluated. Presently, disinfection robots do not replace routine (manual) cleaning but may complement it. Further design adjustments of hospitals and devices are needed to overcome the issue of shadowing and free the movement of robots in the hospital environment. They might in the future provide validated, reproducible and documented disinfection processes. Further technical developments and clinical trials in a variety of hospitals are warranted to overcome the current limitations and to find ways to integrate this novel technology in to the hospitals of to-day and the future

An analysis of the utilisation of chemoprophylaxis against Pneumocystis jirovecii pneumonia in patients with malignancy receiving corticosteroid therapy at a cancer hospital

Pneumocystis jirovecii pneumonia (PCP) is associated with high mortality in immunocompromised patients without human immunodeficiency virus infection. However, chemoprophylaxis is highly effective. In patients with solid tumours or haematologic malignancy, several risk factors for developing PCP have been identified, predominantly corticosteroid therapy. The aims of this study were to identify the potentially preventable cases of PCP in patients receiving corticosteroid therapy at a tertiary care cancer centre and to estimate the frequency of utilisation of chemoprophylaxis in these patients. Two retrospective reviews were performed. Over a 10-year period, 14 cases of PCP were identified: no cases were attributable to failed chemoprophylaxis, drug allergy or intolerance. During a 6-month period, 73 patients received high-dose corticosteroid therapy (⩾25 mg prednisolone or ⩾4 mg dexamethasone daily) for ⩾4 weeks. Of these, 22 (30%) had haematologic malignancy, and 51 (70%) had solid tumours. Fewer patients with solid tumours received prophylaxis compared to patients with haematologic malignancy (3.9 vs 63.6%, P<0.0001). Guidelines for PCP chemoprophylaxis in patients with haematologic malignancy or solid tumours who receive corticosteroid therapy are proposed. Successful primary prevention of PCP in this population will require a multifaceted approach targeting the suboptimal prescribing patterns for chemoprophylaxis

Hedetniemi’s Conjecture and Adjoint Functors in Thin Categories

We survey results on Hedetniemi’s conjecture which are connected to adjoint functors in the “thin” category of graphs, and expose the obstacles to extending these results