116 research outputs found

    Droplet-based digital antibiotic susceptibility screen reveals single-cell clonal heteroresistance in an isogenic bacterial population

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    Since antibiotic resistance is a major threat to global health, recent observations that the traditional test of minimum inhibitory concentration (MIC) is not informative enough to guide effective antibiotic treatment are alarming. Bacterial heteroresistance, in which seemingly susceptible isogenic bacterial populations contain resistant sub-populations, underlies much of this challenge. To close this gap, here we developed a droplet-based digital MIC screen that constitutes a practical analytical platform for quantifying the single-cell distribution of phenotypic responses to antibiotics, as well as for measuring inoculum effect with high accuracy. We found that antibiotic efficacy is determined by the amount of antibiotic used per bacterial colony forming unit (CFU), not by the absolute antibiotic concentration, as shown by the treatment of beta-lactamase-carrying Escherichia coli with cefotaxime. We also noted that cells exhibited a pronounced clustering phenotype when exposed to near-inhibitory amounts of cefotaxime. Overall, our method facilitates research into the interplay between heteroresistance and antibiotic efficacy, as well as research into the origin and stimulation of heterogeneity by exposure to antibiotics. Due to the absolute bacteria quantification in this digital assay, our method provides a platform for developing reference MIC assays that are robust against inoculum-density variations

    Formation of net-like patterns of gold nanoparticles in liquid crystal matrix at the air–water interface

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    Controlled patterning and formation of nanostructures on surfaces based on self-assembly is a promising area in the field of “bottom-up” nanomaterial engineering. We report formation of net-like structures of gold nanoparticles (Au NPs) in a matrix of liquid crystalline amphiphile 4′-n-octyl-4-cyanobiphenyl at the air–water interface. After initial compression to at least 18 mN m(−1), decompression of a Langmuir film of a mixture containing both components results in formation of net-like structures. The average size of a unit cell of the net is easily adjustable by changing the surface pressure during the decompression of the film. The net-like patterns of different, desired average unit cell areas were transferred onto solid substrates (Langmuir–Blodgett method) and investigated with scanning electron microscopy and X-ray reflectivity (XRR). Uniform coverage over large areas was proved. XRR data revealed lifting of the Au NPs from the surface during the formation of the film. A molecular mechanism of formation of the net-like structures is discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11051-012-0826-4) contains supplementary material, which is available to authorized users

    Droplet-based digital antibiotic susceptibility screen reveals single-cell clonal heteroresistance in an isogenic bacterial population

    Get PDF
    Since antibiotic resistance is a major threat to global health, recent observations that the traditional test of minimum inhibitory concentration (MIC) is not informative enough to guide effective antibiotic treatment are alarming. Bacterial heteroresistance, in which seemingly susceptible isogenic bacterial populations contain resistant sub-populations, underlies much of this challenge. To close this gap, here we developed a droplet-based digital MIC screen that constitutes a practical analytical platform for quantifying the single-cell distribution of phenotypic responses to antibiotics, as well as for measuring inoculum effect with high accuracy. We found that antibiotic efficacy is determined by the amount of antibiotic used per bacterial colony forming unit (CFU), not by the absolute antibiotic concentration, as shown by the treatment of beta-lactamase-carrying Escherichia coli with cefotaxime. We also noted that cells exhibited a pronounced clustering phenotype when exposed to near-inhibitory amounts of cefotaxime. Overall, our method facilitates research into the interplay between heteroresistance and antibiotic efficacy, as well as research into the origin and stimulation of heterogeneity by exposure to antibiotics. Due to the absolute bacteria quantification in this digital assay, our method provides a platform for developing reference MIC assays that are robust against inoculum-density variations

    The National and Communitary Protection of Individual Rights in Aquis Communautaire Beyond the Application of Judicial Measures

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    The protection of individual rights within the non-judicial area is no less important that the judicial one, and it is much more often applied. Imprecise as it is, the distinction between the judicial and non-judicial protection does not bear problems in practice. One is entitled to judicial protection in CoJS and CFI and national courts (acting as communal courts) with regard to the violence of rights (protected in acquis communautaire by other units, institutions and legal persons belonging to member states). The protection in national courts deals with the whole range of acquis, including e.g. (after the recent reform in this matter) the right of competition of the EU. Now the judicial protection embraces the following: the right of petition to the European Parliament and the right of complaint to the communal Ombudsman, and numerous complaints to the Commission. With regard to the violence of the communal right (including: cartel plot, public aid, subsidies, antidumping right, and other economic-merchant practices). The non-judicial protection is also enriched by the right to turn to all institutions of the EU in the physical and legal person's mother tongue from the area of the Union, and the duty to answer in this language. Certainty, this type of protection includes also all kinds of means for the protection of the consumer, health protection, and protection of the environment. All authorities and public institutions of the member states are also obliged to provide non-judicial protection in the area of acquis. There are no doubts as to the duties of the EU states that follow from the primary and secondary communal right in the are under consideration. The non-judicial protection in the national systems of entitlements that follow from KPP has no complete juridical justification (it will be introduced by the Constitution for Europe). The mechanisms of protection under discussion exert a positive influence on the enhancement of the international protection of human rights

    Subjectivity of the international organizations (gos) and of the intergovernmental or states conferences – introduction to the problem.

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    Potrzeba stworzenia uznanej definicji podmiotowości (osobowości) międzynarodowej, zwłaszcza takiej, która pozwalałaby na odróżnianie od podmiotów innych niż państwa struktur niepodmiotowych, dotyczy też organizacji i konferencji międzynarodowych (międzyrządowych) sensu largo. Problem tych konferencji bywa poruszany w doktrynie rzadko. Niektóre z nich, zwłaszcza GATT i OBWE, korzystały lub korzystają z niewątpliwej podmiotowości międzynarodowej. Istnieją konferencje wewnątrz organizacji, jak np. unijna IGC, prawotwórcze (np. Rzymska nt. Statutu MTK) i „wewnątrz” traktatów (np. COP w Ramowej Konwencji NZ NT zmian klimatu). Na drugim biegunie są konferencje o minimalnych cechach podmiotowych. Konferencje odgrywają coraz większą rolę w obrocie międzynarodowym. Wszystko to uzasadnia stawiane tu pytania oraz propozycję zarysu badań nad systematyką, prawem, zasadami i procedurami konferencji międzynarodowych. Problem statusu konferencji jest tu chyba najistotniejszy.The necessity to create a widely recognized definition of international personality (especially such that would provide possibility to distinguish subjects from non-subject structures) refers also to international (intergovernmental) organizations and conferences. The problem of the conferences is seldom touched in the doctrine. Some of conferences, especially GATT and CSCE/OSCE used or use undoubtible international subjectivity (and effectivity). On the other end there are conferences with minimal subject features. In classification aspects, there are authonome conferences, conferences inside organizations (GOs) like e.g. IGC of the EU, lawmaking conferences (like Rome Conference on the ICC Statute), or “inside” an international treaty (e.g. COPs & MOPs in the UN Framework Convention of the Climate Changes - UNFCCC). International Organisations and Conferences play a big role in the international legal turn-over. That all justifies questions and proposal of researches on systematics, law and principles of the international conferences status

    For a new approach to human rights in contemporary democracies – effectiveness and pragmatism (proposal de lege ferenda)

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    Obecny model praw człowieka przyjmuje optymistyczne założenie, że ustalony katalog praw jest w pełni realizowany, bez wielu aktów i środków wykonawczych. Poszczególne, ważne prawa w praktyce są jednak słabo chronione, a niedostatek instrumentów nie zapewnia pełnej, dostępnej i skutecznej ochrony. Także w porządku UE przyjmuje się założenie skuteczności unormowanych praw. Powyższe oraz priorytetowy obowiązek państw płynący z zasady zwierzchnictwa narodu implikuje potrzebę nowego ujęcia i regulacji praw człowieka.The current model of human rights (HR) protection includes optimistic supposition, that HR catalogue is to be easy and effectively realized, so it needs a few executive acts and measures. In practice single but important rights are weakly protected and insufficient instruments don’t give them guarantee of complete, effective & accessible protection. Also in the EU legal order it supposes effectiveness of regulated rights. All above mentioned as well as principal obligations of HR protection deriving from supremacy (& sovereignty) of nation are to implicated the need of a new approach and regulations of HR

    Legal Weaknesses of the System and Local Democracy of Warsaw

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    Cel: ustalenie zakresu stosowania konstytucyjnych i ustawowych norm w praktyce m.st. Warszawy oraz skutki status quo dla społeczności lokalnych. Metoda prawno-porównawcza. Wniosek: norma ustrojowa jest jasno określona ale nieadekwatnie stosowana. Istnieje konieczność zmiany tego stanu rzeczy w praktyce prawnej, dla poprawy demokracji i świadomości prawnej społeczeństw lokalnych. Treść: jeśli Konstytucja RP wprowadza prawa społeczeństw lokalnych (a zwłaszcza ich podstawowych jednostek) do samorządności terytorialnej to nie znajduje to odbicia w ustawie warszawskiej, a zwłaszcza w Statucie m.st. Warszawy i Uchwale o przekazaniu niektórych kompetencji dzielnicom. Tak rodzi się niekorzystna dla tych jednostek praktyka. Ograniczanie wspomnianych uprawnień powinno być dostrzegane oraz budzić reakcję społeczeństw lokalnych (chyba niezbyt świadomych swych praw) wobec władz przedstawicielskich, sądów i Trybunału Konstytucyjnego. Stan obecny niekorzystnie wpływa na interesy społeczności lokalnych dzielnic Warszawy, a szerzej także na stosowanie zasad konstytucyjnych przez organy państwa wbrew interesom obywateli. Artykuł ma charakter koncepcyjny.Aim: to provide for the scope of application of constitutional and statutory norms in the practice of the metropolitan city of Warsaw as well as consequences of status quo for local communities. Legal and comparative method. Conclusion: the constitutional norm is clearly defined though inadequately applied. There is the need to change this state of affairs in the legal practice for the purpose of improvement of democracy and legal awareness of local communities. Contents: if the Constitution of the Republic of Poland introduces the rights of local communities (and particularly of their basic units) to the local self-governmental system, this is not reflected in the Warsaw Act, and particularly in the Statutes of the metropolitan city of Warsaw and in the Resolution on delegation of some competencies to districts. Thus there emerges the unfavourable for these units practice. Limitation of the said empowerments should be perceived and should arouse reaction of local communities (perhaps not enough aware of their rights) vis-à-vis representative authorities, courts and the Constitutional Tribunal. The present state unfavourably affects interests of local communities of Warsaw districts and,broader, also the application of the constitutional principles by the state bodies contrary to the citizens’ interests. The article is of the conceptual nature
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