A DNA synthesizer was successfully employed for preparation of well‐defined polymers by atom transfer radical polymerization (ATRP), in a technique termed AutoATRP. This method provides well‐defined ...homopolymers, diblock copolymers, and biohybrids under automated photomediated ATRP conditions. PhotoATRP was selected over other ATRP methods because of mild reaction conditions, ambient temperature, tolerance to oxygen, and no need to introduce reducing agents or radical initiators. Both acrylate and methacrylate monomers were successfully polymerized with excellent control in the DNA synthesizer. Diblock copolymers were synthesized with different targeted degrees of polymerization and with high retention of chain‐end functionality. Both hydrophobic and hydrophilic monomers were grafted from DNA. The DNA‐polymer hybrids were characterized by SEC and DLS. The AutoATRP method provides an efficient route to prepare a range of different polymeric materials, especially polymer‐biohybrids.
Autorad: Photoinduced atom transfer radical polymerization is conducted in an automated DNA synthesizer to prepare well‐defined homopolymers, diblock copolymers, and biohybrids. This technique provides a clean polymerization system under ambient temperature with oxygen tolerance.
Combining synthetic polymers with RNA paves the way for creating RNA-based materials with non-canonical functions. We have developed an acylation reagent that allows for direct incorporation of the ...atom transfer radical polymerization (ATRP) initiator into both short synthetic oligoribonucleotides and natural biomass RNA extracted from torula yeast. The acylation was performed in a quantitative yield. The resulting initiator-functionalized RNAs were used for grafting polymer chains from the RNA by photoinduced ATRP, resulting in RNA-polymer hybrids with narrow molecular weight distributions. The RNA initiator was used for the polymerization of oligo(ethylene oxide) methyl ether methacrylate, poly(ethylene glycol) dimethacrylate, and
-isopropylacrylamide monomers, resulting in RNA bottlebrushes, hydrogels, and stimuli-responsive materials. This approach, readily applicable to both post-synthetic and nature-derived RNA, can be used to engineer the properties of a variety of RNA-based macromolecular hybrids and assemblies providing access to a wide variety of RNA-polymer hybrids.
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We consider quantum quench in large-N singlet sector quantum mechanics of a single hermitian matrix in the double scaling limit. The time dependent parameter is the self-coupling of the ...matrix. We find exact classical solutions of the collective field theory of the eigenvalue density with abrupt and smooth quench profiles which asymptote to constant couplings at early and late times, and with the system initially in its ground state. With adiabatic initial conditions we find that adiabaticity is always broken regardless of the quench speed. In a class of quench profiles the saddle point solution for the collective field diverges at a finite time, and a further time evolution becomes ambiguous. However the underlying matrix model expressed in terms of fermions predict a smooth time evolution across this point. By studying fluctuations around the saddle point solution we interpret the emergent space-times. They generically have spacelike boundaries where the couplings of the fluctuations diverge and the semi-classical description fails. Only for very finely tuned quench profiles, the space-time is normal.
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We investigate a class of exactly solvable quantum quench protocols with a finite quench rate in systems of one dimensional non-relativistic fermions in external harmonic oscillator or ...inverted harmonic oscillator potentials, with time dependent masses and frequencies. These hamiltonians arise, respectively, in harmonic traps, and the
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= 1 Matrix Model description of two dimensional string theory with time dependent string coupling. We show how the dynamics is determined by a single function of time which satisfies a generalized Ermakov-Pinney equation. The quench protocols we consider asymptote to constant masses and frequencies at early times, and cross or approach a gapless potential. In a right side up harmonic oscillator potential we determine the scaling behavior of the one point function and the entanglement entropy of a subregion by obtaining analytic approximations to the exact answers. The results are consistent with Kibble-Zurek scaling for slow quenches and with perturbation calculations for fast quenches. For cis-critical quench protocols the entanglement entropy oscillates at late times around its initial value. For end-critical protocols the entanglement entropy monotonically goes to zero inversely with time, reflecting the spread of fermions over the entire line. For the inverted harmonic oscillator potential, the dual collective field description is a scalar field in a time dependent metric and dilaton background.
There is great global variation in the sleeping arrangements for healthy newborn infants. Bed sharing is a type of sleeping practice in which the sleeping surface (e.g. bed, couch or armchair, or ...some other sleeping surface) is shared between the infant and another person. The possible physiological benefits include better oxygen and cardiopulmonary stability, fewer crying episodes, less risk of hypothermia, and a longer duration of breastfeeding. On the other hand, the most important harmful effect of bed sharing is that it may increase the risk of sudden infant death syndrome (SIDS). Studies have found conflicting evidence regarding the safety and efficacy of bed sharing during infancy.
To evaluate the efficacy and safety of bed sharing, started during the neonatal period, on breastfeeding status (exclusive and total duration of breastfeeding), incidence of SIDS, rates of hypothermia, neonatal and infant mortality, and long-term neurodevelopmental outcomes.
We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2020, Issue 7) in the Cochrane Library; MEDLINE via PubMed (1966 to 23 July 2020), CINAHL (1982 to 23 July 2020), and LILACS (1980 to 23 July 2020). We also searched clinical trials databases, and the reference lists of retrieved articles, for randomised controlled trials (RCTs) and quasi-RCTS.
We planned to include RCTs or quasi-RCTs (including cluster-randomised trials) that included term neonates initiated on bed sharing within 24 hours of birth (and continuing to bed share with the mother in the first four weeks of life, followed by a variable time period thereafter), and compared them to a 'no bed sharing' group.
We used standard methodological procedures as recommended by Cochrane. We planned to use the GRADE approach to assess the certainty of evidence.
Our search strategy yielded 6231 records. After removal of duplicate records, we screened 2745 records by title and abstract. We excluded 2739 records that did not match our inclusion criteria. We obtained six full-text studies for assessment. These six studies did not meet the eligibility criteria and were excluded.
We did not find any studies that met our inclusion criteria. There is a need for RCTs on bed sharing in healthy term neonates that directly assess efficacy (i.e. studies in a controlled setting, like hospital) or effectiveness (i.e. studies conducted in community or home settings) and safety. Future studies should assess outcomes such as breastfeeding status and risk of SIDS. They should also include neonates from high-income countries and low- and middle-income countries, especially those countries where bed sharing is more prevalent because of cultural practices (e.g. Asian countries).
Memory failures are frustrating and often the result of ineffective encoding. One approach to improving memory outcomes is through direct modulation of brain activity with electrical stimulation. ...Previous efforts, however, have reported inconsistent effects when using open-loop stimulation and often target the hippocampus and medial temporal lobes. Here we use a closed-loop system to monitor and decode neural activity from direct brain recordings in humans. We apply targeted stimulation to lateral temporal cortex and report that this stimulation rescues periods of poor memory encoding. This system also improves later recall, revealing that the lateral temporal cortex is a reliable target for memory enhancement. Taken together, our results suggest that such systems may provide a therapeutic approach for treating memory dysfunction.
The development of methodologies for the synthesis of nanoparticles of well‐defined size and shape is a challenging one and constitutes an important area of research in nanotechnology. This Full ...Paper describes the controlled synthesis of multishaped gold nanoparticles at room temperature utilizing a simple, green chemical method by the interaction of chloroauric acid (HAuCl4 · 3H20) and cell‐free extract of the fungal strain Rhizopus oryzae. The cell‐free extract functions as a reducing, shape‐directing, as well as stabilizing, agent. Different shapes of gold nanocrystals, for example, triangular, hexagonal, pentagonal, spherical, spheroidal, urchinlike, two‐dimensional nanowires, and nanorods, are generated by manipulating key growth parameters, such as gold ion concentration, solution pH, and reaction time. The synthesized nanostructures are characterized by UV/Vis and Fourier‐transform infrared spectroscopy, transmission electron microscopy, and energy dispersive X‐ray analysis studies. Electron diffraction patterns reveal the crystalline nature of the nanoparticles and a probable mechanism is proposed for the formation of the different structural entities.
A simple, protein‐mediated, green chemical methodology is proposed for the synthesis of multishaped (triangular, hexagonal, pentagonal, spherical, spheroidal, urchinlike, two‐dimensional nanowires, and nanorods) gold nanostructures. The proteins function as a reducing, shape directing, and stabilizing agent.
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