University of Maryland, College Park

Optoelectronic oscillators are time-delayed photonic systems able to generate pure microwave signals. The nonlinear dynamics of the systems can be well understood using an Ikeda-like equation governing the behavior of the output microwave envelope. This deterministic envelope equation can be converted into a stochastic phase dynamic equation using the Langevin approach, which accounts for both additive and multiplicative noise. Here, we can quantify the magnitude of the two noise contributions in the sub-threshold regime, and show that these measurements are predictive of the phase noise performance of the oscillator above threshold. Our theoretical analysis is found to be in excellent agreement with experimental measurements, which demonstrate a phase noise performance better than –130 dBc/Hz at 10 kHz offset from the carrier in the S-band.

In this paper, we develop a model based on a second quantization—with anharmonic phonon scattering and the phonon Boltzmann transport equation—to study precise high-resolution nonequilibrium vibrational energy transfer (VET) under selective phonon excitation in cyclotrimethylene trinitramine. We simulate mid-infrared pump–probe spectroscopy and observe a prompt appearance (<1 ps) of broad-spectrum intensity, which agrees well with experimental data in the literature. The selective excitation of phonons at different frequencies reveals distinct VET pathways and the kinetic evolution of mode occupations as the system reaches a new equilibrium temperature. Three types of transition mechanisms are found to play outsized roles in terms of the amount of energy transferred and the transfer rate: (1) vibrational modes close to the excited frequencies typically respond faster and reach higher temperatures regardless of the excitation frequency; (2) the overtone pathway connecting the modes near 550 and 1150 cm⁻¹ is an important bridge between far- and mid-IR; and (3) fast aggregation of energy at 2800 cm⁻¹ mediates transfer to/from high frequencies through a second overtone pathway involving modes near 1400 cm⁻¹. In addition, by monitoring the temperature of the N–N/N–O stretching modes, strong coupling between those modes and the C–H stretching modes is found. The coupling likely draws the vibrational modes close to both the proton transfer transition state for HONO elimination and the N–N stretching for bond cleavage. The high-resolution understanding of the nonequilibrium kinetics of phonons provides important insight into the energy transfer and initiation mechanisms of molecular solids due to external stimuli.

We report the synthesis and characterization of sulfated pillar[5]arene hosts (P5S2‐P5S10) that differ in the number of sulfate substituents. All five P5Sn hosts display high solubility in water (73–131 mM) and do not undergo significant self‐association according to ¹H NMR dilution experiments. The x‐ray crystal structures of P5S6, P5S6 ⋅ Me6HDA, P5S8 ⋅ Me6HDA, and P5S10 ⋅ Me6HDA reveal one intracavity molecule of Me6HDA and several external molecules of Me6HDA which form a network of close methonium ⋅ ⋅ ⋅ sulfate interactions. The thermodynamic parameters of complexation between P5Sn and the panel of guests was measured by direct or competitive isothermal titration calorimetry. We find that the binding free energy toward a guest becomes more negative as the number of sulfate substituents increase. Conversely, the binding free energy of a specific sulfated pillar[5]arene toward a homologous series of guests becomes more negative as the number of NMe groups increases. The ability to tune the host ⋅ guest affinity by changing the number of sulfate substituents will be valuable in supramolecular polymers, separation materials, and latching applications.

Acute, intermittent exposure to mild hypoxia increases sympathetic nervous system activity, decreases arterial shear rate, and increases blood pressure (BP) in young men. Given the BP raising effects of intermittent hypoxia (IH) are less evident in young women, we sought to examine the influence of sex on macro- and microvascular function following IH. METHODS: BP, macrovascular function (brachial artery flow-mediated dilation [FMD]), microvascular function (reactive hyperemia area under the curve [RHAUC]), and brachial artery shear rate (shear rate area under the curve [SRAUC]) were measured before and following 30 minutes of IH in 18 young adults (8 women, 23±5y). RESULTS: IH elicited an average nadir blood oxygen saturation (SpO 2 ) of 92±3% (p<0.0001 vs baseline). In men, brachial systolic (bSBP; 116±6 to 122±7 mmHg, p=0.001) and diastolic (bDBP; 116±6 to 122±7 mmHg, p=0.001) BPs increased from baseline following IH. bSBP (110±8 to 111±7 mmHg, p=0.67) and bDBP (64±7 to 68±7 mmHg, p=0.12) were unchanged in women after IH. Men maintained macrovascular function after IH (ΔFMD: 0.75±2.44%) while women exhibited a decline (ΔFMD: -3.09±2.64%, p=0.006 vs men). Microvascular function and shear rate declined following IH independent of sex (RHAUC: 597±306 to 467±205ml/min, p=0.049; SRAUC: 1772±907 to 1439±596s ⁻¹ , p=0.040). CONCLUSION: Acute mild IH increases BP in healthy men, but not women. In women, both micro- and macrovascular function are lower following acute mild IH; in contrast, only micro-vascular function is lower in men. The sex-specific effects of IH on BP and macrovascular function may have important implications for potential beneficial effects of IH.

Objective Crafting high-quality value sets is time-consuming and requires a range of clinical, terminological, and informatics expertise. Despite widespread agreement on the importance of reusing value sets, value set repositories suffer from clutter and redundancy, greatly complicating efforts at reuse. When users encounter multiple value sets with the same name or ostensibly representing the same clinical condition, it can be difficult to choose amongst them or determine if any differences among them are due to error or intentional decision. Methods This paper offers a view of value set development and reuse based on a field study of researchers and informaticists. The results emerge from an analysis of relevant literature, reflective practice, and the field research data. Results Qualitative analysis of our study data, the relevant literature, and our own professional experience led us to three dichotomous concepts that frame an understanding of diverse practices and perspectives surrounding value set development: Permissible values versus analytic value sets; Prescriptive versus descriptive approaches to controlled medical vocabulary use; and Semantic and empirical types of value set development and evaluation practices and the data they rely on. This three-fold framework opens up the redundancy problem, explaining why multiple value sets may or may not be needed and advancing academic understanding of value set development. Conclusion In order for value set repositories to become more rather than less useful over time, software must channel user efforts into either improving existing value sets or making new ones only when absolutely necessary. This would require major, innovative changes to value set repository platforms. We believe the most direct path to giving value set developers the ability to leverage prior work is by encouraging them to compare existing value sets using advanced interfaces like VS-Hub, and by collecting and using metadata about code inclusion and exclusion decisions during the authoring process.

US legislators show a remarkable variation in how many bills and resolutions they sponsor and cosponsor to support Taiwan. I argue that legislators’ perception of China and their partisan identity play a crucial role in shaping their support for Taiwan. To test my hypotheses, I conducted a quantitative analysis of all Taiwan-specific bills and resolutions introduced from the 110th to 116th House of Representatives. The results indicate that legislators who view China as a security threat to the US or a non-democracy and a human rights violator exhibit a higher level of support for Taiwan. However, seeing China as an economic challenger has the least significant effect. Furthermore, although there is a general consensus that Taiwan is a bipartisan issue in Congress, my research demonstrates that Republicans display a greater level of interest in supporting Taiwan compared to Democrats.

This paper examines how digital transformation (DT) impacts carbon emission intensity (CEI) in construction enterprises (CEs) amid global low-carbon development concerns. Using a difference-indifference method on data from 170 Chinese CEs, the study finds that DT significantly reduces CEI. Labour structure upgrading partially mediates this relationship, while the green innovation and green supply chain optimization do not show mediating impacts. The constraining impact of DT on CEI is significant in state-owned and large enterprises but not in non-state-owned and small ones. These insights help understand DT's role in promoting environmentally friendly growth in CEs. ARTICLE HISTORY

Recent work indicates clinically meaningful differences in domains of psychopathic personality – such as grandiose-manipulative (GM), callous-unemotional (CU), and daring-impulsive (DI) traits – and parenting factors. Yet, different domains of parenting and reports from multiple informants may vary in their associations to psychopathic traits. This study examined psychopathic traits and their links with parental monitoring behaviors, parental knowledge, and adolescent disclosure. Further, we evaluated whether adolescents’ self-reported resting arousal moderated these associations. A mixed clinic-referred/community sample of 134 adolescent-parent dyads (Mage = 14.49; SD = 0.50; 66.4% female) completed multi-dimensional measures of psychopathy, parental monitoring behaviors, parental knowledge, and adolescent disclosure; adolescents also self-reported on their resting arousal. Results indicated links between: (a) increased parent-reported GM traits and decreased parent-reported parental knowledge, and (b) increased parent-reported DI traits and lower parent-reported monitoring behaviors, which were attenuated at high levels of adolescent-reported resting arousal. Associations between elevated dimensions of psychopathic traits and lower levels of parental monitoring behaviors, parental knowledge, and adolescent disclosure were most consistent within-informants, with some cross-informant associations identified for links between elevated GM and DI and lower levels of parental monitoring behaviors and parental knowledge. These findings have important implications for our understanding of how to assess and prevent psychopathy and associated externalizing problems, and suggest that targeting modifiable environmental and psychophysiological factors may be particularly important.

The proline amino acid and prolyl residues of peptides/proteins confer unique biological and biochemical properties that motivates the development of proline‐selective analysis. The study focuses on one specific class of problem, the detection of single amino acid variants involving proline, and reports a Pro‐selective electrochemiluminescence (ECL) method. To develop this method, the A1‐/A2‐ variants of milk's β‐casein protein are investigated because it is a well‐established example and abundant samples are readily available. Specifically, β‐casein has 209 amino acids with 34 (or 35) proline residues: the A1‐variant has a Pro‐to‐His substitution at position 67 (relative to the A2 variant). The study shows that proline's strong luminescence allows the generic discrimination of: Pro from other amino acids; an A2‐oligopeptide from an A1‐oligopeptide; the A2‐β‐casein variant from the A1‐variant; and commercially‐available A2 milks from A1‐containing regular milks. The evidence indicates that luminescence depends on proline content and accessibility, as well as signal quenching. Compared to conventional immunoassays, the ECL method is simple, rapid, and inexpensive. Further, the ECL‐method is Pro‐selective (vs molecularly‐selective like typical immunoassays) which should make it broadly useful for studying the role of proline in biology and especially useful for tracking the digestion of proline‐rich proteins in the diet.

The ability to “switch on” adhesion between a thin hydrogel and a biological tissue can be useful in biomedical applications such as surgery. One way to accomplish this is with an electric field, a phenomenon termed electroadhesion (EA). Here, it is shown that cationic gels can be adhered by EA to tissues across all of biology. This includes tissues from animals, including humans and other mammals; birds; fish; reptiles (e.g., lizards); amphibians (e.g., frogs), and invertebrates (e.g., shrimp, worms). Gels can also be adhered to soft tissues from plants, including fruit (e.g., plums) and vegetables (e.g; carrot). In all cases, EA is induced by a low electric field (DC, 10 V) applied for a short time (20 s). After the field is removed, the adhesion persists. The adhesion can also be reversed by applying the field with opposite polarity. In mammals, EA is strong for many tissues (e.g., arteries, muscles, and cornea), but not others (e.g., adipose, brain). Tissues with anisotropic structure show anisotropic adhesion strength by EA. The higher the concentration of anionic polymers in a tissue, the stronger its adhesion to cationic gels. This underscores that EA is mediated by the electrophoresis of chain segments across the gel‐tissue interface.