Infants and toddlers in the United States with more close relationships have larger vocabularies.

Young children learn language from their caregivers, family members, and friends. However, with few exceptions, contemporary developmental scientists have studied language input and language learning through the lens of the primary caregiver and the nuclear family, rather than the infants' broader communities. In many communities-and increasingly in the United States-nonnuclear family structures are common, and extended kin, fictive kin, and intergenerational relationships are relied upon for child care. Understanding children's relationships within kinship networks can allow for more inclusive depictions of children's social interactions and their language experiences. We drew upon methods used by researchers studying social networks to assess U.S. infants' and toddlers' network composition. Results showed that young children with a greater number of close relationships (but not those with larger networks overall) had larger vocabularies, after controlling for age and socioeconomic status. These findings suggest that distributed models of child-rearing are an influential factor in early language growth and call for increased attention to social networks for understanding children's developmental trajectories. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Development of infants' preferential looking toward native language speakers across distinct social contexts.

Presenting pictures of faces side by side is a common paradigm to assess infants' attentional biases according to social categories, such as gender, race, and language. However, seeing static faces does not represent infants' typical experience of the social world, which involves people in motion and performing actions. Here, we assessed infants' looking preferences for native over foreign language speakers in two social contexts: the presentation of static faces and the presentation of people performing instrumental actions. In addition, we tested infants' preferential looking at 5 and 9 months of age to assess whether their pattern of preferential looking changes across development. The results of 5-month-old infants replicated and extended previous findings by showing that, at this age, infants typically look longer at people who previously spoke their native language. As found for other social categories such as race and gender, this familiarity-based looking preference was not evident at 9 months of age when infants were presented with static faces. However, when presented with more informative dynamic events, 9-month-old infants showed a temporally aligned preference for the native over the foreign language speaker. Specifically, infants' looking preference was time-locked to the completion of the action goal: when speakers grasped and lifted a toy. These results suggest potentially a familiarity-based preference toward native language speakers around 5 months of age, which may later develop into a more strategic selective response in service of information-seeking. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Infants' visual attention to own-race and other-race faces is moderated by experience with people of different races in their daily lives.

Infants sometimes differentially attend to faces of different races, but how this tendency develops across infancy and how it may vary for infants growing up with different exposure to racial diversity remain unclear. The present study examined the role of experiences with racial diversity on infants' visual attention to different racial groups (specifically own-race vs. other-race groups) in the first year of life via a large-scale study of infants (N = 203; Mage = 6.9 months, range = 3-14 months; 70% White, 8% Asian, 5% Black, 12% multiracial, 4% unreported; 14% Hispanic, 86% non-Hispanic) from across the United States. We tested the role of two forms of racial diversity: that of infants' social networks (reported by parents) and that of infants' neighborhoods (obtained from U.S. Census data). Regardless of age, infants looked longer at other-race faces than own-race faces, but this tendency was moderated by the racial diversity of infants' social networks. Infants with more diverse networks looked equivalently long at own-race and other-race faces, whereas those with less diverse networks looked longer at other-race faces. In contrast, infants' looking behavior was not moderated by the diversity of their neighborhoods. Together, our research suggests that exposure to racial diversity in infants' immediate social networks predicts how infants look to faces of different races, illustrating the context-dependent nature of the development of infants' attention to race. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Does racial diversity affect White children's racial bias and reasoning? Depends on where they live and how their social world is structured.

By 4 years of age, White children from across the United States begin to exhibit an awareness of racial inequalities, along with in-group preferences for other White children. The present study explored how the size and racial diversity of White children's social network (e.g., friends, family, and classmates) and neighborhood (zip code) are related to variation in their explanations for racial disparities and anti-Black bias among a sample of 395 White children (ages = 4-11 years old; Mage = 6.6 years) from 263 unique zip codes across the United States. White children in neighborhoods with low diversity were more likely to endorse an extrinsic explanation for racial inequality as their network diversity increased, whereas network diversity did not relate to children's choices for those who lived in neighborhoods with high diversity. These findings held even after controlling for parents' beliefs about diversity, which were themselves positively correlated with children's network and neighborhood diversity. An exploratory analysis revealed that for White children in small networks only, as the number of children of color in their network increased, they were more likely to choose to play with a Black child. Results demonstrate how the diversity of children's social networks and neighborhoods relates to children's developing racial beliefs in contextually dependent ways. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Children's social networks in developmental psychology: A network approach to capture and describe early social environments.

Psychologists are interested in understanding how early social environments impact children's behavior and cognition. Early social environments are comprised of social relationships; however, there have been relatively few tools available to quantify the depth and breadth of children's social relationships. We harnessed the power of social networks to demonstrate that networks can be used to describe children's early social environments. Descriptive data from American children aged 6 months-5 years (n = 280; 47% female, 56% White) demonstrates that network properties can be used to provide a quantitative analysis of children's early social environments and highlights how these environments vary across development. Social network methodology will provide researchers with a comprehensive picture of children's early social experiences and improve studies exploring individual differences.

Feature-tracking myocardial strain in healthy adults- a magnetic resonance study at 3.0 tesla.

We analyzed feature-tracking derived circumferential and longitudinal strain in healthy volunteers who underwent cardiac magnetic resonance imaging (CMR) at 3.0 T. 88 healthy adults (44.6 ± 18.0 years old, 49% male), without prior cardiovascular disease, underwent CMR at 3.0 T including cine, and late gadolinium enhancement in subjects >45 years. LV functional analysis and feature-tracking strain analyses were carried out. Global strain had better reproducibility than segmental strain. There was a sex specific difference global longitudinal strain (mean ± SD, -18.48 ± 3.65% (male), -21.91 ± 3.01% (female), p < 0.001), but not global circumferential strain (mean ± SD, -25.41 ± 4.50% (male), -27.94 ± 3.48% (female), p = 0.643). There was no association of strain with ageing after accounting for sex for both global longitudinal and circumferential strain. Feature-tracking strain analysis is feasible at 3.0 T. Healthy female volunteers demonstrated higher magnitudes of global longitudinal strain when compared to male counterparts. Whilst global cine-strain has good reproducibility, segmental strain does not.

Non-sulfated cholecystokinin-8 reduces meal size and prolongs the intermeal interval in male Sprague Dawley rats.

The current study measured seven feeding responses by non-sulfated cholecystokinin-8 (NS CCK-8) in freely fed adult male Sprague Dawley rats. The peptide (0, 0.5, 1, 3, 5 and 10 nmol/kg) was given intraperitoneally (ip) prior to the onset of the dark cycle, and first meal size (MS), second meal size, intermeal interval (IMI) length, satiety ratio (SR = IMI/MS), latency to first meal, duration of first meal, number of meals and 24-hour food intake were measured. We found that NS CCK-8 (0.5 and 1.0 nmol/kg) reduced MS, prolonged IMI length and increased SR during the dark cycle. Furthermore, the specific CCK-B receptor antagonist L365, 260 (1 mg/kg, ip) attenuated these responses. These results support a possible role for NS CCK-8 in regulating food intake.

Conformation-Specific Infrared and Ultraviolet Spectroscopy of Cold [YAPAA+H]+ and [YGPAA+H]+ Ions: A Stereochemical "Twist" on the ß-Hairpin Turn.

Incorporation of the unnatural d-proline (DP) stereoisomer into a polypeptide sequence is a typical strategy to encourage formation of ß-hairpin loops because natural sequences are often unstructured in solution. Using conformation-specific IR and UV spectroscopy of cold (≈10 K) gas-phase ions, we probe the inherent conformational preferences of the DP and LP diastereomers in the protonated peptide [YAPAA+H]+, where only intramolecular interactions are possible. Consistent with the solution-phase studies, one of the conformers of [YADPAA+H]+ is folded into a charge-stabilized ß-hairpin turn. However, a second predominant conformer family containing two sequential γ-turns is also identified, with similar energetic stability. A single conformational isomer of the LP diastereomer, [YALPAA+H]+, is found and assigned to a structure that is not the anticipated "mirror image" ß-turn. Instead, the LP stereocenter promotes a cis-alanine-proline amide bond. The assigned structures contain clues that the preference of the DP diastereomer to support a trans-amide bond and the proclivity of LP for a cis-amide bond is sterically driven and can be reversed by substituting glycine for alanine in position 2, forming [YGLPAA+H]+. These results provide a basis for understanding the residue-specific and stereospecific alterations in the potential energy surface that underlie these changing preferences, providing insights to the origin of ß-hairpin formation.

Alkali Cation Chelation in Cold ß-O-4 Tetralignol Complexes.

We employ cold ion spectroscopy (UV action and IR-UV double resonance) in the gas phase to unravel the qualitative structural elements of G-type alkali metal cationized (X = Li(+), Na(+), K(+)) tetralignol complexes connected by ß-O-4 linkages. The conformation-specific spectroscopy reveals a variety of conformers, each containing distinct infrared spectra in the OH stretching region, building on recent studies of the neutral and alkali metal cationized ß-O-4 dimers. The alkali metal ion is discovered to bind in penta-coordinate pockets to ether and OH groups involving at least two of the three ß-O-4 linkages. Different binding sites are distinguished from one another by the number of M(+)···OH···O interactions present in the binding pocket, leading to characteristic IR transitions appearing below 3550 cm(-1). This interaction is mitigated in the major conformer of the K(+) adduct, demonstrating a clear impact of the size of the charge center on the three-dimensional structure of the tetramer.

Gas-Phase Folding of a Prototypical Protonated Pentapeptide: Spectroscopic Evidence for Formation of a Charge-Stabilized ß-Hairpin.

Ultraviolet and infrared-ultraviolet (IR-UV) double-resonance photofragment spectroscopy has been carried out in a tandem mass spectrometer to determine the three-dimensional structure of cryogenically cooled protonated C-terminally methyl esterified leucine enkephalin [YGGFL-OMe+H](+). By comparing the experimental IR spectrum of the dominant conformer with the predictions of DFT M05-2X/6-31+G(d) calculations, a backbone structure was assigned that is analogous to that previously assigned by our group for the unmodified peptide [ Burke, N.L.; et al. Int. J. Mass Spectrom. 2015 , 378 , 196 ], despite the loss of a C-terminal OH binding site that was thought to play an important role in its stabilization. Both structures are characterized by a type II' ß-turn around Gly(3)-Phe(4) and a γ-turn around Gly(2), providing spectroscopic evidence for the formation of a ß-hairpin hydrogen bonding pattern. Rather than disrupting the peptide backbone structure, the protonated N-terminus serves to stabilize the ß-hairpin by positioning itself in a pocket above the turn where it can form H-bonds to the Gly(3) and C-terminus C═O groups. This ß-hairpin type structure has been previously proposed as the biologically active conformation of leucine enkephalin and its methyl ester in the nonpolar cell membrane environment [ Naito, A.; Nishimura, K. Curr. Top. Med. Chem. 2004 , 4 , 135 - 143 ].