No abstract

Performed through side-chain engineering or by incorporating intramolecular locking units, the directionality and dynamic nature of noncovalent interactions are particularly attractive for the design of novel semiconducting materials in a wide variety of applications. This work investigates the nature and position of hydrogen bonding (intra- versus intermolecular), with the objective of developing a rational approach to the design of new semiconducting materials with improved properties in the solid state. To control the polymer chains’ self-assembly, a π-conjugated polymer incorporating a moiety capable of generating intramolecular hydrogen bonding is evaluated against a polymer that allows for intermolecular hydrogen bonding. Characterization through various techniques, optical spectroscopies, grazing incidence wide-angle x-ray scattering, and solution small-angle neutron scattering showed that intramolecular hydrogen bonds resulted in materials with improved crystallinity and higher effective conjugation in the solid state. Additionally, the effect of the noncovalent interaction configuration on the optoelectronic properties was analyzed in organic field-effect transistor fabrication. Devices prepared from the materials with intramolecular hydrogen bonds showed significantly higher performance, with three orders of magnitude higher charge mobility than their counterparts fabricated from polymers with intermolecular hydrogen bonds. These results confirm the importance of chemical design on polymer structures and offer a novel route for the design of high-efficiency semiconducting polymers for next-generation electronics.

Artificial synaptic thin-film transistor (TFT) devices have recently attracted considerable attention because they can emulate biological synapses, which enables the devices to process and store information like the human brain [1] wherein computation and storage are executed simultaneously-thereby enabling spatiotemporal information processing through timedependent neuron interconnections. Synapses play a major role linking signals transmitted between pre-and postneurons, thereby enabling the brain to function. Neuronal connectivity strength, also known as "plasticity," determines the brain's cognitive intelligence. Adjusting neuronal plasticity enables the brain to concurrently process and store information. [2] Inspired by this collective and adaptive property of human memory, researchers have dedicated considerable effort to developing and implementing neuromorphic computational systems to emulate the brain's strategy of parallel information processing and storage. [3] Such a device would be highly promising for rapidly advancing artificial intelligence [4] because replacing inefficient and high-power-consuming traditional von Neumann-architecture-based computers with separate processor and memory units is feasible. [2c,e,5] To date, synaptic TFT devices have demonstrated their suitability for many practical applications including artificial tactile sensory organs, neurological electronic skin, wearable intelligent electronics, and neuromorphic vision systems. [4a,6] However, fully implementing current devices is limited by numerous challenges. First, most reported devices exhibit sophisticated architectures involving complex fabrication procedures, [1a,5b] which can render such devices expensive and ineffective. In addition, because most reported synaptic devices are electrically operated, they may be limited by the bandwidth/connection-density tradeoff and may exhibit lowspeed signal transmission. [5b,7] Photonic-modulated synaptic devices, on the other hand, have rarely been reported. However, such devices operate based on focused light stimuli exhibiting Although synaptic devices have already demonstrated their operability through electric or photonic signals or a combination thereof, current challenges include developing a single hardware synaptic device that is independently fully operational through either photonic or electric signals to improve device versatility. Additionally, most previously reported devices are fabricated using multiple technical processes-which impede device implementation-while the low-output current triggered in most such devices limits the possible integration of auxiliary gadgets. Therefore, by spontaneously wrapping a conjugated block copolymer around single-walled carbon nanotubes (SWCNTs), a thin-film transistor memory device comprising single-layered poly(9,9-dioctylfluorene)-b-polyisoprene (PF-b-PI)-wrapped-SWCNTs-which function as both a semiconductor and an electret layer-to simplify the device structure and fabrication is designed. Owing to the robust SWCNT ...

Objectives: This study sought to more fully elucidate the age-related trends in influenza mortality with a secondary goal of uncovering implications for treatment and prevention. Methods: In this retrospective cohort analysis of data from the Nationwide Readmission Database, patients with influenza as a primary or secondary discharge diagnosis were separated into three age groups: 55 638 adults aged 20e64 years, 36 862 adults aged 65e79 years and 41 806 octogenarians aged 80 years. Propensity score (PS) weighting was performed to isolate age from other baseline differences. Crude and PS-weighted hazard ratios (HR) were calculated from the in-hospital all-cause 30-day mortality rate. Admission threshold bias was minimized by comparison of influenza with bacterial pneumonia mortality. Results: Adults aged 20e64 years experienced higher in-hospital 30-day mortality compared with older adults aged 65e79 years (HR 0.66; 95% CI 0.55e0.79). Octogenarians had the highest mortality rate, but this was statistically insignificant compared with the adult cohort (HR 1.09; 95% CI 0.94e1.27). This trend was not explained by admission threshold bias: the 30-day mortality rate due to in-hospital bacterial pneumonia increased consistently with age (older adult HR 1.45; 95% CI 1.32e1.59; octogenarian HR 1.99; 95% CI 1.82e2.18). Conclusions: Adults aged 20e64 years and octogenarians were more likely to experience all-cause 30day mortality during influenza hospitalization compared with older adults aged 65e79 years. These data emphasize the importance of prevention and suggest the need for more tailored treatment interventions based on risk stratification that includes age.