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Somitogenesis is a hallmark feature of all vertebrates and some invertebrate species that involves the periodic formation of block-like structures called somites. Somites are transient embryonic segments that eventually establish the entire vertebral column. A highly conserved molecular oscillator called the segmentation clock underlies this periodic event and the pace of this clock regulates the pace of somite formation. Although conserved signaling pathways govern the clock in most vertebrates, the mechanisms underlying the speciesspecific divergence in various clock characteristics remain elusive. For example, the segmentation clock in classical model species such as zebrafish, chick, and mouse embryos tick with a periodicity of ~30, ~90, and ~120 min respectively. This enables them to form the species-specific number of vertebrae during their overall timespan of somitogenesis. Here, we perform a systematic review of the species-specific features of the segmentation clock with a keen focus on mouse embryos. We perform this review using three different perspectives: Notchresponsive clock genes, ligand-receptor dynamics, and synchronization between neighboring oscillators. We further review reports that use non-classical model organisms and in vitro model systems that complement our current understanding of the segmentation clock. Our review highlights the importance of comparative developmental biology to further our understanding of this essential developmental process. [ABSTRACT FROM AUTHOR]

Background: Every year, 350,000 people die from cardiac arrest. However, cardiopulmonary resuscitation (CPR) can double or triple an individual's chance of survival after cardiac arrest. Global CPR Training aims to spread awareness and educate our communities on this life-saving skill, focusing our attention on rural and low-income communities that have higher average emergency response times. Methods: Our free training courses are based on the American Red Cross material and are hour-long classes condensed to efficiently and effectively teach CPR, known as an IMPACT course. These classes are held at the University of Texas at Dallas in designated classrooms and at Stacy Montessori Academy. Participants of our efficacy study are given an emergency cardiac arrest scenario and are scored in a pre-test and post-test based on the completion of specific CPR steps. The instructor provides no prompts, and the results are not shared with the participants. Results: Based on the current analysis of pre-test and posttest results, the Global CPR Training course has resulted in a 185.5% increase in cardiac arrest and CPR knowledge immediately following the class. Conclusions: A future examination will be given one year after each class to verify the validity of our training. Furthermore, to improve the quality of our course, we are receiving feedback from all participants via online survey forms that instructors analyze following every class. The program is expected to increase CPR knowledge and skill retention while also improving out-of-hospital health outcomes involving cardiac arrest in rural and low-income communities. [ABSTRACT FROM AUTHOR]

Membrane based separations offer an inexpensive and energy efficient pathway to purification. However, their use is often stifled during separation of organics due to low selectivity. This can be attributed to the inherent limitations of the synthesis methods employed, namely, interfacial polymerization and phase inversion. In this work, a new class of structure-by-design membranes are synthesized by surface modification of crosslinked polyimide using graft polymerization with a series of methacrylate monomers with differing chain lengths and chemistries. Graft polymerization of long chain monomers resulted in increased selectivity (α∼3.7 for 80-20 mol.% MeOH-toluene and α∼6 for 95-5 mol.% toluene-triisopropyl benzene (TIPB) for both test solutions) as a result of increased stiffness and order (using GIWAXS)). The observed selectivities renders these membranes competitive for organic solvent nanofiltration applications. In addition, pure solvent permeabilities were measured. The performance of these membranes was correlated with brush properties such as degree of grafting (using ATR-FTIR), surface polarity (contact angle measurements), stiffness (using QCM-D) and brush configuration in different solvent environments (using MD Simulations). MD simulations demonstrate that in mixtures containing hydrophobic species, polymers with longer hydrophobic side chains well more and form fuller matrices leading to increased solvent accessible surface area. GIWAXS results showed increased order with longer side chain length. These tunable membranes offer promise for organics separation. [Display omitted] • Tunable structure by design for polymer membranes. • Correlated brush length and brush chemistry with membrane selectivity. • Selectivity of 3.7 for methanol-toluene and ∼6 for toluene-TIPB mixtures. [ABSTRACT FROM AUTHOR]

Drastic reduction in nickel oxide (NiO x ) film resistivity and ionization potential is observed when subjected to ultraviolet (UV)/ozone (O 3 ) treatment. X-ray photoemission spectroscopy suggests that UV/O 3 treatment changes the film stoichiometry by introducing Ni vacancy defects. Oxygen-rich NiO x having Ni vacancy defects behaves as a p-type semiconductor. Therefore, in this work, a simple and effective technique to introduce doping in NiO x is shown. Angle-resolved XPS reveals that the effect of UV/O 3 treatment does not only alter the film surface property but also introduces oxygen-rich stoichiometry throughout the depth of the film. Finally, simple metal/interlayer/semiconductor (MIS) contacts are fabricated on p-type Si using NiO x as the interlayer and different metals. Significant barrier height reduction is observed with respect to the control sample following UV/O 3 treatment, which is in agreement with the observed reduction in film resistivity. From an energy band diagram point of view, the introduction of the UV/O 3 treatment changes the defect state distribution, resulting in a change in the pinning of the Fermi level. Therefore, this work also shows that the Fermi level pinning property of NiO x can be controlled using UV/O 3 treatment.