Expected final online publication date for the Annual Review of Genomics and Human Genetics Volume 22 is August 2021. Please see http//www.annualreviews.org/page/journal/pubdates for revised estimates.The gametophyte represents the sexual phase in the alternation of generations in plants; the other, nonsexual phase is the sporophyte. Here, we review the evolutionary origins of the male gametophyte among land plants and, in particular, its ontogenesis in flowering plants. The highly reduced male gametophyte of angiosperm plants is a two- or three-celled pollen grain. Its task is the production of two male gametes and their transport to the female gametophyte, the embryo sac, where double fertilization takes place. We describe two phases of pollen ontogenesis-a developmental phase leading to the differentiation of the male germline and the formation of a mature pollen grain and a functional phase representing the pollen tube growth, beginning with the landing of the pollen grain on the stigma and ending with double fertilization. We highlight recent advances in the complex regulatory mechanisms involved, including posttranscriptional regulation and transcript storage, intracellular metabolic signaling, pollen cell wall structure and synthesis, protein secretion, and phased cell-cell communication within the reproductive tissues.Purpose Individuals with cerebellar ataxia (CA) caused by cerebellar degeneration exhibit larger reactive compensatory responses to unexpected auditory feedback perturbations than neurobiologically typical speakers, suggesting they may rely more on feedback control during speech. We test this hypothesis by examining variability in unaltered speech. Previous studies of typical speakers have demonstrated a reduction in formant variability (centering) observed during the initial phase of vowel production from vowel onset to vowel midpoint. Centering is hypothesized to reflect feedback-based corrections for self-produced variability and thus may provide a behavioral assay of feedback control in unperturbed speech in the same manner as the compensatory response does for feedback perturbations. Method To comprehensively compare centering in individuals with CA and controls, we examine centering in two vowels (/i/ and /ɛ/) under two contexts (isolated words and connected speech). As a control, we examine speech produced both with and without noise to mask auditory feedback. Results Individuals with CA do not show increased centering compared to age-matched controls, regardless of vowel, context, or masking. Contrary to previous results in neurobiologically typical speakers, centering was not affected by the presence of masking noise in either group. Conclusions The similar magnitude of centering seen with and without masking noise questions whether centering is driven by auditory feedback. However, if centering is at least partially driven by auditory/somatosensory feedback, these results indicate that the larger compensatory response to altered auditory feedback observed in individuals with CA may not reflect typical motor control processes during normal, unaltered speech production.Free-standing crystalline membranes are highly desirable owing to recent developments in heterogeneous integration of dissimilar materials. Van der Waals (vdW) epitaxy enables the release of crystalline membranes from their substrates. However, suppressed nucleation density due to low surface energy has been a challenge for crystallization; reactive materials synthesis environments can induce detrimental damage to vdW surfaces, often leading to failures in membrane release. This work demonstrates a novel platform based on graphitized SiC for fabricating high-quality free-standing membranes. After mechanically removing epitaxial graphene on a graphitized SiC wafer, the quasi-two-dimensional graphene buffer layer (GBL) surface remains intact for epitaxial growth. The reduced vdW gap between the epilayer and substrate enhances epitaxial interaction, promoting remote epitaxy. Significantly improved nucleation and convergent quality of GaN are achieved on the GBL, resulting in the best quality GaN ever grown on two-dimensional materials. The GBL surface exhibits excellent resistance to harsh growth environments, enabling substrate reuse by repeated growth and exfoliation.A ZnO/ZnCl2 composite with stable 3D structural morphologies and long lasting superhydrophilicity was synthesized on the top surface of a nano porous anodic alumina (nanoPAA) substrate. The wettability of a nanoPAA-ZnO/ZnCl2 was systematically characterized and the experimental data indicated that the water contact angle (WCA) of 0° could be achieved as well as maintained over 7 days and still remained at 4.36° after 50 days, and its 3D structural morphology had no clearly observable change during this period. The mechanism for the superhydrophilicity of the composites was interpreted in terms of the inherent hydrophilicity of ZnO/ZnCl2 nanofilm, the three-dimensional structures of wrinkled nanoflakes, the nanogaps between neighbor nanoflakes, the difference of structual morphologies (i.e., size, shape, and upright posture of nanoflakes), and the measured True Volume of voids in the nanocomposite. The structural morphologies were mainly determined by the parameters such as the original concentration of precursor ZnCl2 and the pore diameter of nanoPAA substrate. The study proposes a promising superhydrophilic nanomaterial and a cost-effective synthesis method, which will play a practical role in the fields of biomedical molecular sensors and micro/nanofluidic chips.Random lasers are promising, easy-to-fabricate light sources that rely on scattering instead of well-defined optical cavities. We demonstrate random lasing in GaAs nanowires using both randomly oriented and vertically aligned arrays. These configurations are shown to lase in both resonant and nonresonant modes, where aligned nanowires support predominantly resonant lasing and randomly oriented favors nonresonant lasing. On the basis of numerical simulations, aligning the nanowires increases the system’s scattering efficiency leading to higher quality factor modes and thus favoring the resonant modes. We further demonstrate two methods to optically suppress resonant mode lasing by increasing the number of excited modes. The light output-light input curves show a pronounced kink for the resonant lasing mode while the nonresonant mode is kink-free. The resonant lasing modes may be used as tunable lasers, and the nonresonant modes exhibit near-thresholdless amplification. Switching between lasing modes opens up new opportunities to use lasers in broader applications.A new access to artemisinin is reported based on a selective photochemical hydrothiolation of amorphadiene, a waste product of the industrial semisynthetic route. This study highlights the discovery of two distinctive activation pathways under solvent-free conditions or using a photocatalyst promoting H-abstraction. Subsequently, a chemoselective oxidation of the resulting photochemically generated thioether, followed by a Pummerer rearrangement, affords dihydroartemisinic aldehyde, a key intermediate in the synthesis of artemisinin.The realization of electrically tunable plasmonic resonances in the ultraviolet (UV) to visible spectral band is particularly important for active nanophotonic device applications. However, the plasmonic resonances in the UV to visible wavelength range cannot be tuned due to the lack of tunable plasmonic materials. Here, we experimentally demonstrate tunable plasmonic resonances at visible wavelengths using a chalcogenide semiconductor alloy such as antimony telluride (Sb2Te3), by switching the structural phase of Sb2Te3 from amorphous to crystalline. We demonstrate the excitation of a propagating surface plasmon with a high plasmonic figure of merit in both amorphous and crystalline phases of Sb2Te3 thin films. We show polarization-dependent and -independent plasmonic resonances by fabricating one and two-dimensional periodic nanostructures in Sb2Te3 thin films, respectively. Moreover, we demonstrate electrically tunable plasmonic resonances using a microheater integrated with the Sb2Te3/Si device. The developed electrically tunable Sb2Te3-based plasmonic devices could find applications in the development of active color filters.Introducing magnetism to anionic electrons (AE) of electrides, especially for those confined in two-dimensional (2D) interlayer spaces, could provide a promising way to generate 2D spin-polarized free electron gas. However, the realization of this is challenging. Here, we propose a strategy for generating 2D magnetic AE, which requires two fundamental criteria, i.e., coexistence of localized AE (LAE) and delocalized AE (DAE) and a nearly half-filled LAE. Applying this to Y2C, the magnetism of 2D AE is tunable or sensitive to external strain, hole doping, and layer thickness, depending on the competition between atomic-orbital electrons, DAE, and LAE. Remarkably, a reversible on/off switching of magnetism can be achieved in bilayer Y2C by an electric field. Furthermore, the 2D magnetic AE in Y2C thin films are more robust against oxidation due to spatially selective hole doping effects. The manipulation of spin-polarized 2D AE gas paves a new way for designing spintronic devices with van der Waals magnets.Ultrathin nanoporous (NP) films are an emerging field for selective and effective ion/molecular separation and electrochemical sensing applications. We describe selective ion permeation in surface-functionalized ultrathin NP SiO2 films (NP SiO2-NH2). The ultrathin NP SiO2 films with ca. 8 nm thickness were prepared from silsesquioxane-containing blend polymer Langmuir-Blodgett films (nanosheets) using the photo-oxidation method. The porous SiO2 surface was modified with a pH-responsive amine-containing silane coupling agent. Selective ion permeation was demonstrated under acidic pH conditions (pH ≤ 6) using two equally sized redox probes negative (Fe(CN)63-/4-) and positive (Ru(NH3)62+/3+) ions. The current density for Fe(CN)63-/4- decreased as the pH value increased to pH = 6, whereas it increased for Ru(NH3)62+/3+. Control measurements revealed that the probes can penetrate the pores of nonfunctionalized SiO2 films irrespective of pH values, indicating that both the size and the surface charge response contributed to selective ion permeation. Results obtained from this study pave the way for new applications in molecular separation and sensing applications based on ultrathin nanoporous films ( less then 10 nm) and tailored surfaces.Blending TiO2 and cement to create photocatalytic composites holds promise for low-cost, durable water treatment. However, the efficiency of such composites hinges on cross-effects of several parameters such as cement composition, type of photocatalyst, and microstructure, which are poorly understood and require extensive combinatorial tests to discern. Here, we report a new combinatorial data science approach to understand the influence of various photocatalytic cement composites based on limited datasets. Using P25 nanoparticles and submicron-sized anatase as representative TiO2 photocatalysts and methyl orange and 1,4-dioxane as target organic pollutants, we demonstrate that the cement composition is a more influential factor on photocatalytic activity than the cement microstructure and TiO2 type and particle size. Among the various cement constituents, belite and ferrite had strong inverse correlation with photocatalytic activity, while natural rutile had a positive correlation, which suggests optimization opportunities by manipulating the cement composition.