Itaconic Acid as a Comonomer in Betulin-Based Thermosets via Sequential and Bulk Preparation.

The inherent chemical functionalities of biobased monomers enable the production of renewably sourced polymers that further advance sustainable manufacturing. Itaconic acid (IA) is a nontoxic, commercially produced biobased monomer that can undergo both UV and thermal curing. Betulin is a biocompatible, structurally complex diol derived from birch tree bark that has been recently studied for materials with diverse applications. Here, betulin, IA, and biobased linear diacids, 1,12-dodecanedioic acid (C12) and 1,18-octadecanedioic acid (C18), were used to prepare thermosets using sequential and bulk curing methods. Thermoplastic polyester precursors were synthesized and formulated into polyester-methacrylate (PM) resins to produce sequential UV-curable thermosets. Bulk-cured polyester thermosets were prepared using a one-pot, solventless melt polycondensation using glycerol as a cross-linker. The structure-property relationships of the thermoplastic polyester precursors, sequentially prepared PM thermosets, and bulk-cured polyester thermosets were evaluated with varying IA content. Both types of thermosets exhibited higher storage moduli, Tgs, and thermal stabilities with greater IA comonomer content. These results demonstrate the viability of using IA as a comonomer to produce betulin-based thermosets each with tunable properties, expanding the scope of their applications and use in polymeric materials.

Learning Modality and Quality of Life Among US School-Age Children During the Coronavirus Pandemic.

BACKGROUND: Shifts from in-person learning to virtual and hybrid learning modes in response to the coronavirus pandemic potentially impacted children's physical, emotional, social, and academic development. This study examined the association between virtual, in-person, and hybrid learning modality with parent-reported quality of life among US students (kindergarten-12th) in early 2021. METHODS: Parents reported current learning modality and physical, emotional, social, and school quality of life for children (aged 5-11, n = 1381) and adolescents (aged 12-17, n = 640). Multivariable logistic regression models assessed the odds of impaired quality of life by learning modality. RESULTS: Among children, hybrid and virtual learners had greater odds of impaired quality of life (adjusted odds ratio [aOR] 1.79, 95% confidence interval [CI] 1.22, 2.64 and aOR 1.57, 95% CI 1.17, 2.12, respectively) relative to in-person learners. Among adolescents, virtual learners had greater odds impaired physical (aOR 2.06, 95% CI 1.26, 3.38) and school function (aOR 2.23, 95% CI 1.38, 3.61) relative to in-person learners. CONCLUSIONS: Learning modality was associated with student well-being, and appropriate alternative learning modalities may differ for younger and older students in terms of educational quality and quality of life.

The Effects of Phonotactic Probability and Neighborhood Density on Adults' Word Learning in Noisy Conditions.

Purpose: Noisy conditions make auditory processing difficult. This study explores whether noisy conditions influence the effects of phonotactic probability (the likelihood of occurrence of a sound sequence) and neighborhood density (phonological similarity among words) on adults' word learning. Method: Fifty-eight adults learned nonwords varying in phonotactic probability and neighborhood density in either an unfavorable (0-dB signal-to-noise ratio [SNR]) or a favorable (+8-dB SNR) listening condition. Word learning was assessed using a picture naming task by scoring the proportion of phonemes named correctly. Results: The unfavorable 0-dB SNR condition showed a significant interaction between phonotactic probability and neighborhood density in the absence of main effects. In particular, adults learned more words when phonotactic probability and neighborhood density were both low or both high. The +8-dB SNR condition did not show this interaction. These results are inconsistent with those from a prior adult word learning study conducted under quiet listening conditions that showed main effects of word characteristics. Conclusions: As the listening condition worsens, adult word learning benefits from a convergence of phonotactic probability and neighborhood density. Clinical implications are discussed for potential populations who experience difficulty with auditory perception or processing, making them more vulnerable to noise.

Vegetation and floristics of a lowland tropical rainforest in northeast Australia.

BACKGROUND: Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m(2) quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m(2) ha(-1), of which small stems (tree saplings and shrubs <10cm dbh) and lianas collectively contribute c.4.2%. Comparing the stem density-diversity patterns of the DRO forest with other tropical rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. NEW INFORMATION: We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a meta-analysis of stem densities and species diversity from comparable-sized plots across the tropics.

Reducing the impact of wind noise on cochlear implant processors with two microphones.

Behind-the-ear (BTE) processors of cochlear implant (CI) devices offer little to almost no protection from wind noise in most incidence angles. To assess speech intelligibility, eight CI recipients were tested in 3 and 9 m/s wind. Results indicated that speech intelligibility decreased substantially when the wind velocity, and in turn the wind sound pressure level, increased. A two-microphone wind noise suppression strategy was developed. Scores obtained with this strategy indicated substantial gains in speech intelligibility over other conventional noise reduction strategies tested.

Temporary atrial pacing for cardiac output after pediatric cardiac surgery.

Pediatric cardiothoracic surgery is often associated with low cardiac output in the postoperative period. This study sought to determine whether increasing heart rate via temporary atrial pacing is beneficial in augmenting cardiac output. Patients younger than 18 years who underwent cardiothoracic surgery and had no perioperative arrhythmias were eligible for the study. Patients not paced postoperatively were atrial paced at a rate of 15 % above the intrinsic sinus rate (not to exceed 170 beats per minute, less for older patients) for 15 min. Patients paced for cardiac output postoperatively had their pacemakers paused for 15 min. Markers of cardiac output were measured before and after the intervention. Of the 60 patients who consented to participate, 30 completed the study. Failure to complete the study was due to tachycardia (n = 13), lack of pacing wires (n = 7), junctional rhythm (n = 4), advanced atrioventricular block (n = 3), and other cause (n = 3). Three patients were paced at baseline. There was no change in arteriovenous oxygen saturation difference, mean arterial blood pressure, central venous pressure, toe temperature, or lactate with atrial pacing. Atrial pacing was associated with a decrease in head and flank near-infrared spectroscopy (p = 0.01 and <0.01 respectively). Secondary analysis found an inverse relationship between mean arterial pressure response to pacing and bypass time. Temporary atrial pacing does not improve cardiac output after pediatric cardiac surgery and may be deleterious. Future research may identify subsets of patients who benefit from this strategy. Practitioners considering this strategy should carefully evaluate each patient's response to atrial pacing before its implementation.

Body temperature circadian rhythm variability corresponds to left ventricular systolic dysfunction in decompensated cardiomyopathic hamsters.

BACKGROUND: A declining amplitude of body temperature circadian rhythm (BTCR) predicts decompensation or death in cardiomyopathic hamsters. We tested the hypothesis that changes in BTCR amplitude accompany significant changes in left ventricular (LV) size and function. METHODS AND RESULTS: Using intraperitoneal transmitters, we continuously monitored the temperature of 30 male BIO TO-2 Syrian dilated cardiomyopathic hamsters. Cosinor analysis was used to detect significant changes--defined as changes >1 standard deviation from the baseline amplitude for 3 consecutive days--in BTCR amplitude over each hamster's lifespan. The Student t-test was used to compare BTCR variability and LV size and function (as assessed by 2D echocardiography) between baseline and the time that BTCR amplitude declined. All hamsters received 10 mg/kg furosemide daily. At the time of BTCR amplitude decline, functional parameters had changed significantly (P < .0001) from baseline: ejection fraction (0.31 ± 0.09% vs. 0.52 ± 0.08%), LV end-systolic volume (0.11 ± 0.03 vs. 0.05 ± 0.02 cm(3)), and LV end-diastolic volume (0.16 ± 0.04 vs. 0.10 ± 0.03 cm(3)). CONCLUSIONS: In decompensated cardiomyopathic hamsters, a decline in BTCR amplitude was associated with progression of heart failure and cardiac decompensation. Variation in BTCR warrants further investigation because of its potential implications for the diagnosis and treatment of cardiovascular disorders.

Circadian body temperature variability is an indicator of poor prognosis in cardiomyopathic hamsters.

BACKGROUND: Low body temperature is an independent predictor of poor prognosis in patients with congestive heart failure. The cardiomyopathic hamster develops progressive biventricular dysfunction, resulting in heart failure death at 9 months to 1 year of life. Our goal was to use cardiomyopathic hamsters to examine the relationship between body temperature and heart failure decompensation and death. METHODS AND RESULTS: To this end, we implanted temperature and activity transducers with telemetry into the peritoneal space of 46 male Bio-TO-2 Syrian cardiomyopathic hamsters. Multiple techniques, including computing mean temperature, frequency domain analysis, and nonlinear analysis, were used to determine the most useful method for predicting poor prognosis. Data from 44 hamsters were included in our final analysis. We detected a decline in core body temperature in 98% of the hamsters 8+/-4 days before death (P < .001). We examined the dominant frequency of temperature variation (ie, the circadian rhythm) by using cosinor analysis, which revealed a significant decrease in the amplitude of the body temperature circadian rhythm 8 weeks before death (0.28 degrees C; 95% CI, 0.26-0.31) compared to baseline (0.36 degrees C; 95% CI, 0.34-0.39; P=.005). The decline in the circadian temperature variation preceded all other evidence of decompensation. CONCLUSIONS: We conclude that a decrease in the amplitude of the body temperature circadian rhythm precedes fatal decompensation in cardiomyopathic hamsters. Continuous temperature monitoring may be useful in predicting preclinical decompensation in patients with heart failure and in identifying opportunities for therapeutic intervention.

Protein-resistant silicones: incorporation of poly(ethylene oxide) via siloxane tethers.

Silicones with enhanced protein resistance were prepared by introducing poly(ethylene oxide) (PEO) chains via siloxane tethers (a-c) of varying lengths. Three unique ambifunctional molecules (a-c) having the general formula alpha-(EtO)3Si(CH2)2-oligodimethylsiloxanen-block-poly(ethylene oxide)8-OCH3 (n = 0 (a), 4, (b), and 13 (c)) were prepared via regioselective Rh-catalyzed hydrosilylation. Nine films were subsequently produced by the H3PO4-catalyzed sol-gel cross-linking of a-c each with alpha,omega-bis(Si-OH)polydimethylsiloxane (P, Mn = 3000 g/mol) in varying ratios (1:1, 1:2, and 2:3 molar ratio a, b, or c to P). Films prepared with a 2:3 molar ratio (a-c to P) contained the least amount of un-cross-linked materials, which may migrate to the film surface. For this set of films, surface hydrophilicity and protein resistance increased with siloxane tether length (a-c). These results indicate that PEO was more effectively mobilized to the surface if incorporated into silicones via longer siloxane tethers.