Nanomotion Detection Method for Testing Antibiotic Resistance and Susceptibility of Slow‐Growing Bacteria

Infectious diseases are caused by pathogenic microorganisms and are often severe. Time to fully characterize an infectious agent after sampling and to find the right antibiotic and dose are important factors in the overall success of a patient's treatment. Previous results suggest that a nanomotion detection method could be a convenient tool for reducing antibiotic sensitivity characterization time to several hours. Here, the application of the method for slow‐growing bacteria is demonstrated, taking Bordetella pertussis strains as a model. A low‐cost nanomotion device is able to characterize B. pertussis sensitivity against specific antibiotics within several hours, instead of days, as it is still the case with conventional growth‐based techniques. It can discriminate between resistant and susceptible B. pertussis strains, based on the changes of the sensor's signal before and after the antibiotic addition. Furthermore, minimum inhibitory and bactericidal concentrations of clinically applied antibiotics are compared using both techniques and the suggested similarity is discussed.     

Kinematic analysis of three-link spatial mechanisms containing sphere-plane and sphere-groove pairsAnalyse cinématique des mécanismes spatiaux a trois barres contenant les paires sphère-plan et sphère-rainure

Kinematic pairs in a spatial mechanism are viewed either as allowing relative screw motion between links or as constraining the motion of the two chains of the mechanism connected to the two elements of the pair. Using pair geometry constraints of the sphere-plane and sphere-groove kinematic pairs, the displacement, velocity and accelerations equations are derived for, R-Sp-R, 5 R-Sp-P, P-Sp-P, P-Sp-R and R-Sg-C three-link mechanisms. For known values of the input variable, other variables are computed in closed form. The analysis procedures are illustrated using numerical examples.     

Biodistribution of single and aggregated gold nanoparticles exposed to the human lung epithelial tissue barrier at the air-liquid interface

Background

The lung represents the primary entry route for airborne particles into the human body. Most studies addressed possible adverse effects using single (nano)particles, but aerosolic nanoparticles (NPs) tend to aggregate and form structures of several hundreds nm in diameter, changing the physico-chemical properties and interaction with cells. Our aim was to investigate how aggregation might affect the biodistribution; cellular uptake and translocation over time of aerosolized NPs at the air-blood barrier interface using a multicellular lung system.

Results

Model gold nanoparticles (AuNPs) were engineered and well characterized to compare single NPs with aggregated NPs with hydrodynamic diameter of 32 and 106 nm, respectively. Exposures were performed by aerosolization of the particles onto the air-liquid interface of a three dimensional (3D) lung model. Particle deposition, cellular uptake and translocation kinetics of single and aggregated AuNPs were determined for various concentrations, (30, 60, 150 and 300 ng/cm²) and time points (4, 24 and 48 h) using transmission electron microscopy and inductively coupled plasma optical emission spectroscopy. No apparent harmful effect for single and aggregated AuNPs was observed by lactate dehydrogenase assay, nor pro-inflammation response by tumor necrosis factor α assessment. The cell layer integrity was also not impaired. The bio-distribution revealed that majority of the AuNPs, single or aggregated, were inside the cells, and only a minor fraction, less than 5%, was found on the basolateral side. No significant difference was observed in the translocation rate. However, aggregated AuNPs showed a significantly faster cellular uptake than single AuNPs at the first time point, i.e. 4 h.

Conclusions

Our studies revealed that aggregated AuNPs showed significantly faster cellular uptake than single AuNPs at the first time point, i.e. 4 h, but the uptake rate was similar at later time points. In addition, aggregation did not affect translocation rate across the lung barrier model since similar translocation rates were observed for single as well as aggregated AuNPs.

     

HaloTag-Targeted Sirtuin-Rearranging Ligand (SirReal) for the Development of Proteolysis-Targeting Chimeras (PROTACs) against the Lysine Deacetylase Sirtuin 2 (Sirt2)**

We have discovered the sirtuin-rearranging ligands (SirReals) as a novel class of highly potent and selective inhibitors of the NAD⁺-dependent lysine deacetylase sirtuin 2 (Sirt2). In previous studies, conjugation of a SirReal with a ligand for the E3 ubiquitin ligase cereblon to form a so-called proteolysis-targeting chimera (PROTAC) enabled small-molecule-induced degradation of Sirt2. Herein, we report the structure-based development of a chloroalkylated SirReal that induces the degradation of Sirt2 mediated by Halo-tagged E3 ubiquitin ligases. Using this orthogonal approach for Sirt2 degradation, we show that other E3 ligases than cereblon, such as the E3 ubiquitin ligase parkin, can also be harnessed for small-molecule-induced Sirt2 degradation, thereby emphasizing the great potential of parkin to be used as an E3 ligase for new PROTACs approaches. Thus, our study provides new insights into targeted protein degradation in general and Sirt2 degradation in particular.     

Determination of the condition of existence of complete crank rotation and of the instantaneous efficiency of spatial four-bar mechanismsBestimmung der existenzbedingung einer kurbel und des momentanen wirkungsgrades räumlicher viergliedriger mechanismen

This paper treats the derivation of the general conditions of existence of complete crank rotation in spatial RS_sSR and RS_sSP four-bar mechanisms. These conditions take the form of inequalities which must be satisfied by the coefficients of a quartic equation, with the tangent of the output half-angle as the unknown. Previously derived criteria for special cases (such as the planar four-link mechanism and the 3D-slider-crank) are shown to agree with the new general conditions. The instantaneous quasi-static efficiency of these mechanisms is also presented.     

A linearized lumped parameter approach to vibration and stress analysis of elastic linkagesAnalyse des contraintes et des vibrations des mecanismes aux barres flexibles par la methode de discretisation lineare des parametres

Nonlinear equations of motion resulting from the lumped-mass modeling of mechanism links are linearized and decoupled by using the concept of kinematic influence coefficients. Effect of rotatory inertia of elements and end masses of moving links is investigated. Equations of motion are solved by way of the central finite difference method. The model is applied to a planar four-bar linkage corresponding to an actual mechanism that has been examined experimentally and analyzed by non-linear lumped parameter method. The results show that the error due to linearization is small and that rotatory inertia has significant effect on the elastic response of the mechanism.     

Pulmonary artery banding is not contraindicated in double inlet left ventricle with transposition and aortic arch obstruction

It has been widely stated that pulmonary artery banding (PAB) is contraindicated in the setting of double inlet left ventricle with transposition of the great vessels (DILV/TGA), especially if aortic arch obstruction is present. We postulated that the poor results for this condition reflect the tendency to leave the band in place long-term without early recognition and relief of subaortic stenosis (SAS). Short-term PAB with early relief of SAS remains an attractive option compared to a neonatal "Norwood" strategy. We reviewed our results applying this approach to 18 consecutive infants presenting since 1980 with DILV/TGA and an obstructive anomaly of the aortic arch (coarctation 16, interruption or atresia 2). Four of the infants (22%) were considered to have important SAS at presentation. One underwent neonatal aortopulmonary connection and died. The remaining 17 patients underwent arch repair with PAB (median age 1.4 weeks; range 2 days-22 weeks) with one early death. The 16 survivors have been followed for 5.6 +/- 3.7 years. All but one ultimately developed SAS. Relief of SAS was performed in 15 patients (median age 8 months) using a proximal aortopulmonary anastomosis. There were two early deaths, and one late death. Thirteen of the 18 patients (72%) are alive and well, and 12 have achieved Fontan repair or bidirectional superior cavopulmonary anastomosis (BCPA) with persistent relief of SAS. Most patients with DILV/TGA and aortic arch obstruction will tolerate temporary PAB with adequate protection of the pulmonary vascular bed. Our current approach (in the absence of severe SAS at presentation) is PAB at the time of arch repair, followed by careful surveillance for, and early relief of, SAS combined with BCPA in infancy.     

Secret key rate proof of multicarrier continuous‐variable quantum key distribution

We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaussian subchannels from the physical quantum channel, each dedicated to the transmission of a subcarrier CV. The Gaussian subcarriers are decoded by a unitary CV operation, which results in the recovered single‐carrier Gaussian CVs. We derive the formulas through the adaptive multicarrier quadrature division (AMQD) scheme, the singular value decomposition (SVD)–assisted AMQD, and the multiuser AMQD multiuser quadrature allocation (MQA). We prove that the multicarrier CVQKD leads to improved secret key rates and higher tolerable excess noise in comparison with single‐carrier CVQKD. We derive the private classical capacity of a Gaussian subchannel and the security parameters of an optimal Gaussian collective attack in the multicarrier setting. We reveal the secret key rate formulas for one‐way and two‐way multicarrier CVQKD protocols, assuming homodyne and heterodyne measurements and direct and reverse reconciliation. The results reveal the physical boundaries of physically allowed Gaussian attacks in a multicarrier CVQKD scenario and confirm that the improved transmission rates lead to enhanced secret key rates and security thresholds.     

Computer reconstruction of luminal cross-sectional shape from multiple cineangiographic views

Knowledge of coronary luminal shape, in addition to diameter information as routinely obtained from a cineangiogram, may be useful in assessing lesions which deviate from circular symmetry. We have developed an image analysis system for automated tracking of luminal edges and measurement of diameter form cine frames digitized by a video camera/digitizer interfaced to a Vax 11/780 computer. Between vessel edges, cinedensitometric profiles across the vessel long axis are used to provide a rotationally invariant measure of relative luminal cross-sectional area. A maximum entropy iterative algorithm is used to reconstruct the lumen cross section from a set of projection data consisting of the cinedensitometric profiles from multiple radiographic views. Nonaxisymmetric model coronary lumena, such as a crescent shape and a double lumen simulating a coronary artery dissection, were filmed under cineradiographic conditions similar to clinical exposures. Radiographic views at 10 degrees increments about the model lumen long axis over 360 degrees were available for analysis. Graphic display of reconstructed model lumena indicate that as few as three to five radiographic views may be useful in reconstructing coronary luminal shape.