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Objectives: To resolve the controversy regarding the presence of a microbiota in the placenta.Design: Classical and molecular microbiological study.Setting: All samples were collected during caesarean section.Population: A total of 28 human placentas and six murine placentas.Methods: All 28 human placentas were checked for 16S rRNA gene amplification products. Three locations from four selected human placentas and three 'environmental controls' for each placenta were placed in seven culture media. The four selected human placentas were further analysed using Gram stain, immunohistochemistry for bacteria, electron microscopy, and TaqMan RT-qPCR. Six placentas from three SPF mice were cut into four pieces each, and further analysed for 16S rRNA gene amplification.Main Outcome Measures: Microbiological and molecular evidence of bacteria.Results: None of the placental cultures used for the full analysis, or their environmental cultures, was positive for bacterial growth. None of the other methods showed any evidence of bacteria. Immunohistochemistry showed negligible bacterial counts. None of the murine placentas showed evidence of 16S rRNA gene amplification.Conclusions: Our results support that the fetal environment in the womb is sterile. Based on the immunohistochemistry and the limit of detection of the other methods used, if a placental microbiome exists, it is of extreme low biomass, and thus its effect on clinical phenotypes is probably minor, if it exists at all.Tweetable Abstract: Using several microbiological and molecular methods in parallel, we found no compelling evidence of bacteria in human and mouse placentas. [ABSTRACT FROM AUTHOR]

Studies were carried out to test whether tolerance to alloantigens and to heterologous proteins could be induced in (NZB x NZW)Fi (B/W) female mice, compared with females of various other mouse strains, including BALB/c, C3H/eb, C57B1/Ka and (BALB/c x C57B1/6)F1. Untreated BALB/c and B/W mice were resistant to tolerance induction by deaggregated BSA, while all other strains were susceptible, as indicated by their lack of response to antigen challenge. Tolerance induction to BSA was further potentiated in all mouse strains including BALB/c with the exception of B/W, following prior conditioning of the mice with total lymphoid irradiation (TLI). Similarly, specific and permanent tolerance to H-2 incompatible alloantigens was successfully induced in TLI conditioned BALB/c, C3H/eb, (BALB/c x C57B1/6)F1 injected with bone marrow cells, however, B/W mice were resistant. Stable chimeras could be established in TLI treated B/W mice only across a semi-allogeneic combination (BALB/c-> B/W). No graft vs host disease (GVHD) was observed in any of the chimeras including BJW mice. We conclude that B/W mice are resistant to tolerance induction to heterologous proteins and alloantigens, even after TLI conditioning. We postulate that this phenomenon is a function of both the intrinsic properties of the haemopoietic stem cells, including their differentiated progeny, as well as characteristics of their cellular microenvironment. [ABSTRACT FROM AUTHOR]

Sequential infiltration synthesis (SIS), also known as vapor phase infiltration (VPI), is a quickly expanding technique that allows growth of inorganic materials within polymers from vapor phase precursors. With an increasing materials library, which encompasses numerous organometallic precursors and polymer chemistries, and an expanding application space, the importance of understanding the mechanisms that govern SIS growth is ever increasing. In this work, we studied the growth of polycrystalline ZnO clusters and particles in three representative polymers: poly(methyl methacrylate), SU-8, and polymethacrolein using vapor phase diethyl zinc and water. Utilizing two atomic resolution methods, high-resolution scanning transmission electron microscopy and synchrotron X-ray absorption spectroscopy, we probed the evolution of ZnO nanocrystals size and crystallinity level inside the polymers with advancing cycles─from early nucleation and growth after a single cycle, through the formation of nanometric particles within the films, and to the coalescence of the particles upon polymer removal and thermal treatment. Through in situ Fourier transform infrared spectroscopy and microgravimetry, we highlight the important role of water molecules throughout the process and the polymers' hygroscopic level that leads to the observed differences in growth patterns between the polymers, in terms of particle size, dispersity, and the evolution of crystalline order. These insights expand our understanding of crystalline materials growth within polymers and enable rational design of hybrid materials and polymer-templated inorganic nanostructures.

Sequential infiltration synthesis (SIS) is an emerging technique for fabricating hybrid organic-inorganic materials with nanoscale precision and controlled properties. Central to SIS implementation in applications such as membranes, sensors, and functional coatings is the mechanical properties of hybrid materials in water-rich environments. This work studies the nanocomposite morphology and its effect on the mechanical behavior of SIS-based hybrid thin films of AlO x -PMMA under aqueous environments. Water-supported tensile measurements reveal an unfamiliar behavior dependent on the AlO x content, where the modulus decreases after a single SIS cycle and increases with additional cycles. In contrast, the yield stress constantly decreases as the AlO x content increases. A comparison between water uptake measurements indicates that AlO x induces water uptake from the aqueous environment, implying a "nanoeffect" stemming from AlO x -water interactions. We discuss the two mechanisms that govern the modulus of the hybrid films: softening due to increased water absorption and stiffening as the AlO x volume fraction increases. The decrease in the yield stress with SIS cycles is associated with the limited mobility and extensibility of polymer chains caused by the growth of AlO x clusters. Our study highlights the significance of developing hybrid materials to withstand aqueous or humid conditions which are crucial to their performance and durability.

Biofilms are responsible for about considerable amounts of cases of bacterial infections in humans. They are considered a major threat to transplant and chronic wounds patients due to their highly resistant nature against antibacterial materials and due to the limited types of techniques that can be applied to remove them. Here we demonstrate a successful in-situ bio-assisted synthesis of dual functionality nanoparticles composed of Silver and Gold. This is done using a jellyfish-based scaffold, an antibacterial material as the templating host in the synthesis. We further explore the scaffold's antibacterial and photothermal properties against various gram-negative and positive model bacteria with and without photo-induced heating at the Near-IR regime. We show that when the scaffold is loaded with these bimetallic nanoparticles, it exhibits dual functionality: Its photothermal capabilities help to disrupt and remove bacterial colonies and mature biofilms, and its antibacterial properties prevent the regrowth of new biofilms., (© 2021. The Author(s).)

Nanoscale devices that utilize oxygen vacancies in two-dimensional metal-oxide structures garner much attention due to conductive, magnetic, and even superconductive functionalities they exhibit. Ferroelectric domain walls have been a prominent recent example because they serve as a hub for topological defects and hence are attractive for next-generation data technologies. However, owing to the light weight of oxygen atoms and localized effects of their vacancies, the atomic-scale electrical and mechanical influence of individual oxygen vacancies has remained elusive. Here, stable individual oxygen vacancies were engineered in situ at domain walls of seminal titanate perovskite ferroics. The atomic-scale electric-field, charge, dipole-moment, and strain distribution around these vacancies were characterized by combining advanced transmission electron microscopy and first-principle methodologies. The engineered vacancies were used to form quasi-linear quadrupole topological defects. Significant intraband states were found in the unit cell of the engineered vacancies, proposing a meaningful domain-wall conductivity for miniaturized data-storage applications. Reduction of the Ti ion as well as enhanced charging and electric-field concentration were demonstrated near the vacancy. A 3-5% tensile strain was observed at the immediate surrounding unit cells of the vacancies. Engineering individual oxygen vacancies and topological solitons thus offers a platform for predetermining both atomic-scale and global functional properties of device miniaturization in metal oxides.

Interfaces at the two-dimensional limit in oxide materials exhibit a wide span of functionality that differs significantly from the bulk behavior. Among such interfaces, domain walls in ferroelectrics draw special attention because they can be moved deterministically with external voltage, while they remain at place after voltage removal, paving the way to novel neuromorphic and low-power data-processing technologies. Ferroic domains arise to release strain, which depends on material thickness, following Kittel's scaling law. Hence, a major hurdle is to reduce the device footprint for a given thickness, i.e., to form and move high-density domain walls. Here, we used transmission electron microscopy to produce domain walls with periodicity as high as 2 nm without the use of contact electrodes, while observing their formation and dynamics in situ in BaTiO3. Large-area coverage of the engineered domain walls was demonstrated. The domain-wall density was found to increase with increasing effective stress, until arriving at a saturation value that reflects 150-fold effective stress enhancement. Exceeding this value resulted in strain release by domain rotation. In addition to revealing this multiscale strain-releasing mechanism, we offer a device design that allows controllable switching of domain-walls with 2 nm periodicity, reflecting a potential 144 Tb per inch2 neuromorphic network.

Mechanical displacement in commonly used piezoelectric materials is typically restricted to linear or biaxial in nature and to a few percent of the material dimensions. Here, we show that free-standing BaTiO 3 membranes exhibit nonconventional electromechanical coupling. Under an external electric field, these superelastic membranes undergo controllable and reversible "sushi-rolling-like" 180° folding-unfolding cycles. This crease-free folding is mediated by charged ferroelectric domains, leading to giant >3.8 and 4.6 μm displacements for a 30 nm thick membrane at room temperature and 60 °C, respectively. Further increasing the electric field above the coercive value changes the fold curvature, hence augmenting the effective piezoresponse. Finally, it is found that the membranes fold with increasing temperature followed by complete immobility of the membrane above the Curie temperature, allowing us to model the ferroelectric domain origin of the effect.

Objectives: To resolve the controversy regarding the presence of a microbiota in the placenta., Design: Classical and molecular microbiological study., Setting: All samples were collected during caesarean section., Population: A total of 28 human placentas and six murine placentas., Methods: All 28 human placentas were checked for 16S rRNA gene amplification products. Three locations from four selected human placentas and three 'environmental controls' for each placenta were placed in seven culture media. The four selected human placentas were further analysed using Gram stain, immunohistochemistry for bacteria, electron microscopy, and TaqMan RT-qPCR. Six placentas from three SPF mice were cut into four pieces each, and further analysed for 16S rRNA gene amplification., Main Outcome Measures: Microbiological and molecular evidence of bacteria., Results: None of the placental cultures used for the full analysis, or their environmental cultures, was positive for bacterial growth. None of the other methods showed any evidence of bacteria. Immunohistochemistry showed negligible bacterial counts. None of the murine placentas showed evidence of 16S rRNA gene amplification., Conclusions: Our results support that the fetal environment in the womb is sterile. Based on the immunohistochemistry and the limit of detection of the other methods used, if a placental microbiome exists, it is of extreme low biomass, and thus its effect on clinical phenotypes is probably minor, if it exists at all., Tweetable Abstract: Using several microbiological and molecular methods in parallel, we found no compelling evidence of bacteria in human and mouse placentas., (© 2019 Royal College of Obstetricians and Gynaecologists.)

Here, we optimized ultrathin films of granular NbN on SiO 2 and of amorphous αW 5 Si 3 . We showed that hybrid superconducting nanowire single-photon detectors (SNSPDs) made of 2 nm thick αW 5 Si 3 films over 2 nm thick NbN films exhibit advantageous coexistence of timing (<5 ns reset time and 52 ps timing jitter) and efficiency (>96% quantum efficiency) performance. We discuss the governing mechanism of this hybridization via the proximity effect. Our results demonstrate saturated SNSPDs performance at 1550 nm optical wavelength and suggest that such hybridization can significantly expand the range of available superconducting properties, impacting other nano-superconducting technologies. Lastly, this hybridization may be used to tune properties, such as the amorphous character of superconducting films.

Purpose: Prolonged febrile seizures (PFS) lasting ≥15 min have been associated with increased risk for epilepsy in later life. Initial treatment, mostly prehospital, aims to prevent its evolution to febrile status epilepticus (FSE) and reduce adverse outcome. Paucity of information is available on the immediate treatment before reaching a hospital facility., Methods: We obtained data, prospectively, on all children who presented from January 2008 to March 2010 with PFS to the emergency rooms of four Israeli medical centers. Information related to seizure semiology, treatment, and medical history was collected into a predefined pro forma form and reviewed centrally., Key Findings: Sixty children, median age 18.3 months (interquartile range [IQR] 12-28) were included with a median seizure duration of 35 min (IQR 26-60), 43 (71.7%) lasting ≥30 min. Seizures had focal onset in 34 infants (57%). Fifty-four families (90%) activated the ambulance service; median ambulance arrival time was 8 min (IQR 5-10), 33 (61%) were medically treated by the ambulance paramedic, of whom 15 (45%) responded to treatment. Twelve children with active seizures did not receive medications. Initial treatment with rectal diazepam was more common in those with seizure duration >30 min., Significance: Most children with PFS are treated with antiepileptic drugs early by the ambulance service. However, even timely treatment does not prevent status epilepticus in the majority of cases. These data highlight the need for effective early treatment of this common pediatric emergency., (Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.)

Studies were carried out to test whether tolerance to alloantigens and to heterologous proteins could be induced in (NZB X NZW)F1 (B/W) female mice, compared with females of various other mouse strains, including BALB/c, C3H/eb, C57Bl/Ka and (BALB/c X C57Bl/6)F1. Untreated BALB/c and B/W mice were resistant to tolerance induction by deaggregated BSA, while all other strains were susceptible, as indicated by their lack of response to antigen challenge. Tolerance induction to BSA was further potentiated in all mouse strains including BALB/c with the exception of B/W, following prior conditioning of the mice with total lymphoid irradiation (TLI). Similarly, specific and permanent tolerance to H-2 incompatible alloantigens was successfully induced in TLI conditioned BALB/c, C3H/eb, (BALB/c X C57Bl/6)F1 injected with bone marrow cells, however, B/W mice were resistant. Stable chimeras could be established in TLI treated B/W mice only across a semi-allogeneic combination (BALB/c--greater than B/W). No graft vs host disease (GVHD) was observed in any of the chimeras including B/W mice. We conclude that B/W mice are resistant to tolerance induction to heterologous proteins and alloantigens, even after TLI conditioning. We postulate that this phenomenon is a function of both the intrinsic properties of the haemopoietic stem cells, including their differentiated progeny, as well as characteristics of their cellular microenvironment.

The role of IgD (delta) in the induction of tolerance in murine B lymphocytes was explored in the in vivo adoptive antibody response to bovine serum albumin (BSA). Delta+ or delta- B cells purified on the fluorescence-activated cell sorter were injected, with or without purified T cells, into lethally irradiated intermediate hosts, which were rendered tolerant by an injection of deaggregated BSA one day after the cell transfer. Spleen cells from the intermediate hosts were treated with anti-Thy-1.2 antiserum and complement mixed with normal T cells and were transferred to final hosts. The ability of the B cells of the final hosts to respond to the tolerogen BSA and to dinitrophenylated human gamma globulin antigen was examined. This approach enabled examination of the function of the B cell subpopulations in an environment free of tolerogen and of induced T suppressor cells. The results revealed that in the presence of T cells the delta+ subpopulation was highly resistant to tolerance induction, whereas the delta- subpopulation was highly susceptible to tolerance induction. However, there was no difference in susceptibility to tolerance induction between the two subpopulations when tolerance was induced in the absence of T cells.