bluuebunny/crossref_metadata_2025 huggingface dataset:
The contribution of community service during the transition to adulthood to health in adulthood
Authors: Wray‐Lake Laura , Dunn Danielle , Freund Valerie , Kloska Deborah D.
Published: February 2024

Prior studies have linked young people's community service to indicators of health, yet little research takes the long view by connecting youth's community service to health in the next decade of life. Using a lifespan developmental lens, this study examined community service over the transition to adulthood and uses change over time in community service to predict indicators of behavioral, physical, and psychological health at ages 35 and 40. Data were taken from Monitoring the Future U.S. national multi‐cohort data spanning ages 18–40 in high school cohorts from 1976 to 1995 for age 40 (N = 4300) and 1976 to 2000 for age 35 (N = 5879). Models estimated a growth curve model for community service from ages 18 to 30 and found that the slope for community service was associated with alcohol use, binge drinking, marijuana use, healthy behaviors, and life satisfaction at ages 35 and 40, with cigarette use at age 35 only, and with self‐esteem and depressive symptoms at age 40 only. Less decline in community service over the transition to adulthood was associated with lower substance use, more healthy behaviors, and higher psychological well‐being in adulthood. This study contributes evidence that community service and health are linked across the lifespan and suggests the value of examining the long‐term implications of developmental change across adolescence and the transition to adulthood.
Association between perioperative self‐reported sleep disturbances and delirium risk in elderly patients following total joint arthroplasty: a cohort study
Authors: Chen Hao , Fang Zheng , Wu Yang‐yang , Zhao Cheng‐hui , Wang Yu‐jie , Zhu Xiao‐he , Cheng Xin‐qi
Published: February 2024

Perioperative sleep disturbance may increase delirium risk. However, the role of perioperative sleep disturbance in delirium following total joint arthroplasty remains unclear. This prospective cohort study aimed to observe the delirium risk in patients with sleep disturbances. After excluding pre‐existing sleep disturbances, older patients scheduled for total joint arthroplasty from July 17, 2022, to January 12, 2023, were recruited. Preoperative sleep disturbance or postoperative sleep disturbance was defined as a Chinese version of the Richards–Campbell Sleep Questionnaire (RCSQ) score of <50 during hospitalisation. A cut‐off score of 25 was used to classify the severity of sleep disturbance. The primary outcome was the incidence of postoperative delirium. In all, 11.6% of cohort patients (34/294) developed delirium. After multivariate analysis, a preoperative Day 1 RCSQ score of ≤25 (odds ratio [OR] 3.62, 95% confidence interval [CI] 1.19–10.92; p = 0.02), occurrence of sleep disturbances (OR 2.76, 95% CI 1.19–6.38; p = 0.02) and RCSQ score of ≤25(OR 2.91, 95% CI 1.33–6.37; p = 0.007) postoperatively were strong independent predictors of delirium. After sensitivity analysis for daily delirium, a postoperative Day 1 RCSQ score of ≤25 (OR 9.27, 95% CI 2.72–36.15; p < 0.001) was associated with a greater risk of delirium on postoperative Day 1, with a reasonable discriminative area under the curve of 0.730. We concluded that postoperative but not preoperative sleep disturbances may be an independent factor for delirium risk. Sleep disturbance on the first night after surgery was a good predictor of subsequent delirium, no matter the nature of self‐reported sleep disturbance.
The U.S. Supreme Court and democratic backsliding
Authors: Keck Thomas M.
Published: February 2024

This paper assesses the performance of the Supreme Court as democratic guardrail during five prior periods of democratic crisis in the United States. It finds that most such periods witnessed efforts by the governing regime to entrench themselves in power, and that the Court has rarely provided an effective check on such democratic abuses. Rather than serving as a reliable democratic guardrail, the Court has regularly exercised what Dixon and Landau call “weak‐form abusive judicial review”; that is, it has declined to check attacks on democracy emerging from other centers of power. On one occasion, the Court has undermined democracy even more directly via “strong‐form abusive judicial review”; that is, the Court itself attacked key democratic guardrails. This historical record provides a helpful baseline for evaluating the Court's performance during the Trump era, when it has taken actions that both protect and undermine democratic health. Conflicting signs indicate that the Court is playing a more democracy‐protective role than most of its predecessors in some respects, but a more democracy‐undermining role in others. As such, it is too soon to say with confidence whether the contemporary Court will be remembered, on balance, for resolving or exacerbating a system‐threatening constitutional crisis.
Biofloc technology: A sustainable approach towards wastewater utilization and fish production
Authors: Kumar Sudhir , Srivastava Praveen Kumar , Kumar Vineet , Seth Chandra Shekhar
Published: February 2024

Biofloc technology (BFT) has gained popularity recently as the aquaculture industry faces significant economic losses due to water pollution creating various pathogens. Many bacterial, viral and fungal diseases in fish cause a decrease in annual world fish production. Therefore, owing to a growing demand for healthy fish, zero‐water exchange is widely practiced in fish and shellfish production. It minimizes the release of aquaculture wastewater into the aquatic ecosystem, which contains nutrients, organic matter and pathogens. It uses a minimal amount of land, which provides an impartial cost–benefit ratio to maintain socio‐economic sustainability. Besides sustainability, fish cultured in the BFT have also expressed better health status after being challenged by different pathogens. However, this review explores the use of BFT as a sustainable approach to wastewater utilization and fish and shellfish production. Apart from this, the review highlights the potential of BFT to enhance fish production in aquaculture systems and discusses various factors that affect the performance of systems, such as carbon‐to‐nitrogen ratios, aeration and the use of probiotics. It also investigates the role of biofloc in improving water quality, fish and shellfish health prophylactic properties, and its effect on gut microflora. The review further examines the economic feasibility of BFT and discusses about the cost‐effectiveness of implementing systems and the potential for generating additional revenue through the sale of bioflocs as a value‐added product. Overall, this review highlights the potential of BFT as a sustainable solution for wastewater utilization and increasing fish production. It provides valuable insights into the factors affecting the performance of BFT systems and suggests areas for further research and development in this field.
An overview of the current status of Lake Jipe and its biodiversity dilemma
Authors: Orina Paul Sagwe , Chepkirui Mercy , Orina Tonny , Akwany Leonard , Joseph Rasowo , Matuma Mercy , Kyule Domitilah , Okechi John , Munguti Jonathan
Published: February 2024

Lake Jipe, is a shared water resource between Kenya and Tanzania located at the East African Coast is under multiple pressures. The present study assessed the current state of Lake Jipe and its biodiversity dilemma. Random sampling was conducted at 14 sampling points set at equidistant parallel to each other. Sampling depths and location coordinates were measured using Solar Transducer and GPSMAPS® 65 s. In situ water quality parameters were measured using YSI Pro Plus multiparameter; water samples for nutrients analysis were collected and preserved in cooler boxes prior transportation to Kenya Marine and Fisheries Research Institute (KMFRI) laboratory for analysis according to ALPHA 2005. Socio‐economic data in relation to status of Lake Jipe ecology were generated using Key Informants Interviews at identified beaches along Kenya and Tanzania. Present findings indicated that the lake has receded from the original 108.72 Km2 to 27.32 Km2 with annual temperatures, dissolved oxygen and conductivity of 28.58 ± 0.95, 5.19 ± 00 and 799.24 ± 69.41, respectively, for dry season. Wet season recorded 31.21 ± 0.31, 4.16 ± 0.01 and 882.44 ± 57.41 for temperature, dissolved oxygen and conductivity, respectively. Agricultural activities have significantly (90%) contributed to the lake levels decline and further affected the lakes' aquatic biodiversity. Among the most affected are the commercially important endemic fish species of the lake of which Oreochromis jipe has experienced the greatest decline. Overfishing, use of illegal unreported and unregulated fishing gears, intensified fishing along protected fish breeding areas as well as poor management and uncoordinated conservation efforts have significantly contributed to the decline of fish catches from 348 kg of O. jipe in 2016 to 90 kg daily catches in 2022. Consequently, the lake is in the verge of extinction if no action is taken. This calls for awareness on the significance of the L. Jipe ecosystems and its immediate and long‐term benefits. Further, there is need to revive and promote alternative economic activities including sustainable aquaculture and agriculture to local communities.
Critically re‐examining professional norms: Medicine's urgent need to look inwards
Authors: Sternszus Robert , Snell Linda , Razack Saleem
Published: February 2024

'Are physicians who they ought to be?' This commentary advocates for a critical re‐examination of what is at the core of being a physician via a process of inclusive co‐construction
The protein phosphorylation landscape in photosystem I of the desert algae Chlorella sp.
Authors: Levin Guy , Yasmin Michael , Pieńko Tomasz , Yehishalom Nitsan , Hanna Rawad , Kleifeld Oded , Glaser Fabian , Schuster Gadi
Published: February 2024

The phosphorylation of photosystem II (PSII) and its antenna (LHCII) proteins has been studied, and its involvement in state transitions and PSII repair is known. Yet, little is known about the phosphorylation of photosystem I (PSI) and its antenna (LHCI) proteins.

Here, we applied proteomics analysis to generate a map of the phosphorylation sites of the PSI–LHCI proteins in Chlorella ohadii cells that were grown under low or extreme high‐light intensities (LL and HL). Furthermore, we analyzed the content of oxidized tryptophans and PSI–LHCI protein degradation products in these cells, to estimate the light‐induced damage to PSI–LHCI.

Our work revealed the phosphorylation of 17 of 22 PSI–LHCI subunits. The analyses detected the extensive phosphorylation of the LHCI subunits Lhca6 and Lhca7, which is modulated by growth light intensity. Other PSI–LHCI subunits were phosphorylated to a lesser extent, including PsaE, where molecular dynamic simulation proposed that a phosphoserine stabilizes ferredoxin binding. Additionally, we show that HL‐grown cells accumulate less oxidative damage and degradation products of PSI–LHCI proteins, compared with LL‐grown cells.

The significant phosphorylation of Lhca6 and Lhca7 at the interface with other LHCI subunits suggests a physiological role during photosynthesis, possibly by altering light‐harvesting characteristics and binding of other subunits.
Ca2+ regulates developmental timing in Arabidopsis
Authors: Poethig R. Scott
Published: February 2024

This article is a Commentary on Wang et al. (2024), 242: 1043–1054.
Member duality and policy tourism: Learning in interlocal policy networks
Authors: Liu Ivy S. , Yi Hongtao
Published: February 2024

Organizational learning has long been recognized as a key determinant of success, yet research often overlooks how individual mechanisms initiate and drive collective learning over time. Utilizing policy tourism as an indicator of intercity learning, we construct an interlocal learning network among US cities from 2009 to 2016. Employing a temporal exponential random graph model, our findings suggest that the member duality of local managers can initiate and facilitate self‐organizing learning interactions among US cities through preferential attachment. Consequently, a core group of influential cities with member duality of local managers can control entry into the learning network and strategically promote the transmission of innovative management practices in particular cities. This study (1) underscores the significance of member duality in local managers for facilitating interorganizational learning, (2) incorporates the aspect of temporality in understanding interorganizational learning, and (3) highlights broader practical implications for collaborative governance in diverse network settings.
Management of civil services and the supply of civil servants
Authors: Yang Wenhui , Zhao Siyuan
Published: February 2024

This study proposes an organization–person framework and examines whether management of public officials shapes capable young elites' preferences of government jobs. Using a conjoint experiment in China, we find that monetary and nonmonetary traits of governments jobs alter capable young elites' motivations to engage in public service. In particular, merit‐based selection rule and high wages attract more capable young elites to serve in public services. In contrast, campaign‐style corruption investigation may deter them from serving in government. Furthermore, the effects of civil service management are contingent upon individuals' attributes. Individuals with political connections are less likely to prefer merit‐based selection rules and more likely care about the economic return on government jobs, but intensive corruption investigation is more likely to crowd out those with weak public service motivation.
Diabetes and lung function: Linked, but how?
Authors: James Alan
Published: February 2024

See related article
Gait biomechanics do not differ between adolescents with and without patellofemoral pain
Authors: Mazzella Natalie , Trowell Danielle , Fox Aaron , Saunders Natalie , Vicenzino Bill , Bonacci Jason
Published: February 2024

Objectives

To determine if adolescents with patellofemoral pain exhibit different biomechanical characteristics to asymptomatic adolescents during walking and running.

Methods

Twenty‐eight adolescents with patellofemoral pain (16 male, 12 female, mean [SD] age: 14.3 [1.7] years) and 24 asymptomatic adolescents (13 male, 11 female, mean [SD] age: 14.1 [1.6] years) participated. Participants walked and ran on an instrumented treadmill in a standardized athletic shoe. Continuous hip, knee, and ankle joint angles and moments, and frontal plane pelvic motion were compared between groups using one‐dimensional statistical parametric mapping independent t‐tests (alpha <0.05). Cadence and stride length were compared between groups using independent t‐tests.

Results

During walking, adolescents with patellofemoral pain had a higher hip extension moment at 7%–8% of the gait cycle (p = 0.04) and walked with a shorter stride length (mean difference [95% confidence interval] = −0.07 [−0.1, −0.01] m). There were no other differences between groups during walking. During running, adolescents with patellofemoral pain had greater knee flexion than asymptomatic adolescents at 35%–40% of the gait cycle (p = 0.04) and ran with a higher cadence (mean difference [95% confidence interval] = 5.8 [2.0, 9.5] steps/min). There were no other statistically significant differences between groups during running.

Conclusions

Adolescents with patellofemoral pain demonstrate few biomechanical differences to asymptomatic adolescents during walking and running. The identified differences are likely of limited clinical importance. Biomechanical alterations which have been previously associated with patellofemoral pain in adults, may not need to be the target of management of adolescent patellofemoral pain.
Traumatic subcutaneous emphysema following blood donation: A case report
Authors: Singh Pallavi , Nair K Revathy , Batra Akshay , Singh Satyendra Narayan
Published: February 2024

Background

Subcutaneous emphysema is a condition where air becomes trapped under the skin, typically resulting from surgery or skin trauma. It is mostly localized and its occurrence in blood donors is exceedingly rare. Phlebotomy poses minimal risk of subcutaneous emphysema, but procedural errors may lead to such complications.

Study Design and Method

This is a case report of 29‐year‐old repeat blood donor who experienced subcutaneous emphysema following blood donation. The donor was vigorously squeezing sponge ball during donation resulting in displacement of the needle which required readjustment. Post‐donation, the donor reported a crackling sensation and mild swelling near phlebotomy site. Non‐contrast computed tomography (NCCT) scans confirmed subcutaneous emphysema, attributing its development to air trapping in subcutaneous plane due to ball valve mechanism.

Results

Computed tomography (CT) imaging revealed subcutaneous emphysematous changes in the right cubital region and no evidence of hematoma. The swelling spontaneously subsided in 10–12 days without any intervention. The case underscores the importance of differentiating subcutaneous emphysema from common complications like hematoma.

Discussion

Subcutaneous emphysema in blood donors is exceptionally rare but should be managed with clear communication. Donors should be reassured that the condition, although rare, is benign and self‐resolving. Healthcare providers should be equipped to handle such rare complications, offering appropriate care and documenting incidents for future prevention.
Influence of screw configuration on reduction and stabilization of simulated complete lateral condylar fracture in equine limbs
Authors: Brabon Ashley , Hughes Kristopher James , Jensen Kelsey , Xie Gang , Labens Raphael
Published: February 2024

Objective

To determine the influence of screw configuration on the reduction and stabilization of simulated complete lateral condylar fracture.

Study design

Randomized experimental crossover study.

Methods

A lateral condylar fracture was simulated in 18 cadaver limbs from nine horses. Each limb underwent repair with 4.5 mm diameter cortex screws, tightened to 4 Nm, in a linear and triangular configuration. Computed tomography (CT) of each repair was performed with the limbs in unloaded and loaded conditions. Fracture gaps were measured at the dorsal, palmar, and middle locations of the third metacarpal condyle. Fracture gap measurements were graded 0–4, based on voxels. Following descriptive analysis, a Bayesian network (BN) model was fitted to the data.

Results

The median fracture grade was 0 (range: 0–4) for unloaded linear repairs and 2 (0–4) for loaded linear repairs. The median fracture grade was 0 (0–3) for unloaded triangular repairs and 1 (0–3) for loaded triangular repairs. Bayesian network sensitivity analysis showed that the construct configuration reduced the uncertainty in the measured fracture outcome by 0.8%.

Conclusion

Triangular screw configuration resulted in better fracture reduction and stability in comparison with linear screw configuration. However, the BN sensitivity analysis results showed that the effect of construct configuration on fracture outcome was weak.

Clinical significance

These findings indicate a low probability that triangular repair of lateral condylar fracture will result in improved outcomes, when compared with linear repair.
Exceptional biases in counting primes over function fields
Authors: Bailleul Alexandre , Devin Lucile , Keliher Daniel , Li Wanlin
Published: February 2024

We study how often exceptional configurations of irreducible polynomials over finite fields occur in the context of prime number races and Chebyshev's bias. In particular, we show that three types of biases, which we call “complete bias,” “lower order bias,” and “reversed bias,” occur with probability going to zero among the family of all squarefree monic polynomials of a given degree in as , a power of a fixed prime, goes to infinity. The bounds given extend a previous result of Kowalski, who studied a similar question along particular one‐parameter families of reducible polynomials. The tools used are the large sieve for Frobenius developed by Kowalski, an improvement of it due to Perret–Gentil and considerations from the theory of linear recurrence sequences and arithmetic geometry.
La corrupción en dos contextos contrapuestos: Casos de Colombia y Suiza
Authors: Jositsch Daniel , Córdoba Pulido Anamaria
Published: February 2024

El presente artículo busca efectuar un análisis comparado del fenómeno de la corrupción en escenarios que figurativamente se muestran como contrapuestos. La percepción derivada de la puntuación de los índices de corrupción sitúa a la muestra del estudio en dos segmentos opuestos, donde uno de los países se cataloga con los puntajes mas bajos de corrupción, y en cambio el otro, es posicionado como uno que detenta altos índices del fenómeno. La relación entre las políticas criminales, y las respuestas en los marcos jurídicos, serán los encargados de revelar el desarrollo e impacto que ha tenido el fenómeno de la corrupción en estos escenarios, y en virtud de este diagnóstico, la presente investigación aspira entender la causa de la corrupción en cada uno de estos entornos, para finalmente revelar si verdaderamente las cifras que nos presentan como índices de corrupción, obedecen de manera inequívoca con la situación real respecto a la presencia de esta problemática, y si las soluciones que se plantean son las adecuadas para lograr mitigar su ocurrencia.
An Enhanced Nonlinear Energy Sink for Hybrid Bifurcation Passive Mitigation and Energy Harvesting From Aeroelastic Galloping Phenomena
Authors: Ignacio da Silva José Augusto , Sanches Leonardo , Michon Guilhem , Marques Flavio Donizeti
Published: February 2024

Galloping is a self-excited vibration problem that structures immersed in fluid flow can experience. Due to its essential nonlinear phenomena, the structure exhibits limit cycle oscillations (LCOs), which, at high levels, can lead to failure of the systems. This work proposes an investigation of electromagnetic-enhanced nonlinear energy sinks (NES-EH) for the hybrid mitigation of aeroelastic LCOs and energy harvesting. The study focuses on a prismatic bluff body with a linear suspension immersed in the airflow, using classical steady nonlinear modeling for aerodynamic loads. The conventional NES approach is adopted, employing cubic stiffness and linear damping. Additionally, a linear electromagnetic transducer is included in the assembly for the energy harvesting process. By combining the method of multiple scales with the Harmonic Balance Method, analytical solutions are derived to characterize the system's dynamics under the influence of the device. The different response domains and their respective boundaries induced by the NES-EH are characterized based on the bifurcation diagrams. Furthermore, a slow invariant manifold (SIM) characterization is presented for each induced response domain, and its significant features are discussed. Parametric studies are carried out based on bifurcation analyses to assess the effect of NES-EH parameters on the galloping system dynamics, which allows for designing the absorber parameters. The electrical resistance is optimized to maximize the harvested power. The optimal design of NES-EH is then compared with classical energy harvesting solutions for the galloping problem. Additionally, a thorough analysis of the Target Energy Transfer phenomenon is performed.
Infrared photoelectric detection of polycrystalline Bi2Te3 thin films prepared by pulsed laser deposition
Authors: Kao Qijun , Xiao Yi , Jia Yongfeng , Wang Jin , Wang Chuanbin
Published: February 2024

In the context of infrared photodetectors, the performances of infrared materials determine the photoresponse performance of devices. Bismuth telluride (Bi2Te3), as a topological insulator, is considered a strong competitor in the field of infrared photodetectors. In this study, polycrystalline Bi2Te3 thin films were prepared using pulsed laser deposition at different growth temperatures. The crystallization of Bi2Te3 films commenced at 150 °C, and with an increase in the preparation temperature, the crystal quality improved, reaching its peaks at 250 °C. Infrared performance of polycrystalline Bi2Te3 thin films were measured at low temperature, featuring a high responsivity of 56.98 mA/W and outstanding detectivity of 1.82 × 109 Jones, surpassing that of other two-dimensional materials. In a low-temperature environment, amorphous Bi2Te3 films are more prone to reaching photocurrent saturation compared to their crystalline counterparts. The generation of saturable photocurrent can be attributed to the effect of defect and disorder. Simultaneously, the presence of lattice defects enhances the photoresponse of the films. Essentially, these founding will pave the way to investigate of Bi2Te3 thin films for applications in infrared photodetectors.
High current field emission from Si nanowires on pillar structures
Authors: Buchner Philipp , Hausladen Matthias , Bartl Mathias , Bachmann Michael , Schreiner Rupert
Published: February 2024

We investigate the influence of the geometry and doping level on the performance of n-type silicon nanowire field emitters on silicon pillar structures. Therefore, multiple cathodes with 50 by 50 pillar arrays (diameter: 5 μm, height: 30 μm, spacing: 50 μm) were fabricated and measured in diode configuration. In the first experiment, we compared two geometry types using the same material. Geometry 1 is black silicon, which is a highly dense surface covering a forest of tightly spaced silicon needles resulting from self-masking during a plasma etching process of single crystal silicon. Geometry 2 are silicon nanowires, which are individual spaced-out nanowires in a crownlike shape resulting from a plasma etching process of single crystal silicon. In the second experiment, we compared two different silicon doping levels [n-type (P), 1–10 and <0.005 Ω cm] for the same geometry. The best performance was achieved with lower doped silicon nanowire samples, emitting 2 mA at an extraction voltage of 1 kV. The geometry/material combination with the best performance was used to assemble an integrated electron source. These electron sources were measured in a triode configuration and reached onset voltages of about 125 V and emission currents of 2.5 mA at extraction voltages of 400 V, while achieving electron transmission rates as high as 85.0%.
Self-powered solar blind ultraviolet photodetector based on amorphous (In0.23Ga0.77)2O3/bixbyite (In0.67Ga0.33)2O3 heterojunction
Authors: Nie Yiyin , Lu Hongliang , Jiao Shujie , Wang Xianghu , Yang Song , Wang Dongbo , Gao Shiyong , Fu Zhendong , Li Aimin , Wang Jinzhong
Published: February 2024

Self-powered solar-blind ultraviolet photodetectors are considered for potential applications in secure communication and space detection. However, high-quality p-type wide bandgap semiconductors are nonexistent due to the self-compensation effect, which makes the design of p-n homojunction photodetectors a challenging proposition to date. In this work, a self-powered solar-blind ultraviolet photodetector is fabricated and discussed, based on a novel heterojunction of (InxGa1−x)2O3 ternary alloy films with two different compositions, which has a flexible design and can be easily fabricated for different applications. The heterojunction consists of an amorphous (In0.23Ga0.77)2O3 on the top of a bixbyite (In0.67Ga0.33)2O3 film prepared by radio frequency magnetron sputtering. The amorphous (In0.23Ga0.77)2O3/bixbyite (In0.67Ga0.33)2O3 heterojunction photodetector exhibits a responsivity of 5.78 mA/W, a detectivity of 1.69 × 1011 cm Hz1/2 W−1, and a high solar-blind UV (248 nm)/visible light (450 nm) rejection ratio of 1.39 × 103 at zero bias, suggesting decent spectral selectivity and high performance. The responsivity and peak wavelength of this photodetector can be tuned by the film thickness of the amorphous (In0.23Ga0.77)2O3. This work provides a new design for self-powered solar-blind UV detectors based on ternary alloy heterojunctions.
Voltage decay in an RLC circuit is not what is taught: An advanced laboratory exercise
Authors: Kowalski Frank V. , Swantek Justin L. , D'Esposito Tony , Brannum Jacob
Published: February 2024

At first glance, a simple model of an RLC circuit taught in undergraduate courses provides a reasonable fit to experimental data. However, careful analysis demonstrates that this model does not accurately describe the behavior of the oscillations in this circuit and requires further refinement. Measuring and analyzing data from this system provides an opportunity for advanced lab students to engage in hypothesis construction, modeling, and experimental design as they seek to explain the discrepancy between these data and a model. The learning outcomes of this activity are consistent with the AAPT guidelines on the undergraduate laboratory experience. Furthermore, such experimentation allows students to bridge the gap between classroom learning and the real world.
On the normalization and density of 1D scattering states
Authors: Lin Chris L.
Published: February 2024

The normalization of scattering states is more than a rote step necessary to calculate expectation values. This normalization actually contains important information regarding the density of the scattering spectrum (along with useful details on the bound states). For many applications, this information is more useful than the wavefunctions themselves. In this paper, we show that this correspondence between scattering state normalization and the density of states is a consequence of the completeness relation, and we present formulas for calculating the density of states, which are applicable to certain potentials. We then apply these formulas to the delta function potential and the square well. We then illustrate how the density of states can be used to calculate the partition function for a system of two particles with a point-like (delta potential) interaction.
Playing melodies on a single string by exciting harmonics using the Lorentz force
Authors: Wei Yukai , Zhu Hao , Jiang Haotian , Luo Quanxin , Lin Shan , Li Junqing , Zhang Yu , Zhao Bibo
Published: February 2024

We show how a single metal guitar string of fixed length can produce a musical scale. The string is placed near a permanent magnet, and by applying an AC to the string at the frequency of the desired musical note, the Lorentz force creates vibrations in the string at that frequency. The tension of the string is set so that its harmonics correspond to the desired notes. A one-octave scale can be approximated by using these harmonic frequencies, allowing several melodies to be played using our non-contact monochord. This project could be adopted for demonstration or laboratory projects.
The uncertainty principle and quantum wave functions that are their own Fourier transforms
Authors: Zengel Keith , DeVitto Nick , Hillyer Nathanael , Rodden Jeffrey , Vu Vinh
Published: February 2024

We present several variations of a proof of the position-momentum uncertainty principle that are based on the calculus of variations and does not rely on the Cauchy–Schwartz inequality. We show that the stationary uncertainty wave functions are the Hermite–Gaussian solutions to the quantum harmonic oscillator problem, that the minimum uncertainty wave function is the Gaussian, and that stationary uncertainty wave functions must be their own Fourier transforms. We also provide a calculus of variations proof of the Cauchy–Schwartz inequality. Finally, we discuss the properties of wave functions that are their own Fourier transforms and provide examples of such functions that may be of interest to teachers of undergraduate and graduate level quantum mechanics courses.
Fast and slow: Recording neuromodulator dynamics across both transient and chronic time scales
Authors: Ma Pingchuan , Chen Peter , Tilden Elizabeth I. , Aggarwal Samarth , Oldenborg Anna , Chen Yao
Published: February 2024

Neuromodulators transform animal behaviors. Recent research has demonstrated the importance of both sustained and transient change in neuromodulators, likely due to tonic and phasic neuromodulator release. However, no method could simultaneously record both types of dynamics. Fluorescence lifetime of optical reporters could offer a solution because it allows high temporal resolution and is impervious to sensor expression differences across chronic periods. Nevertheless, no fluorescence lifetime change across the entire classes of neuromodulator sensors was previously known. Unexpectedly, we find that several intensity-based neuromodulator sensors also exhibit fluorescence lifetime responses. Furthermore, we show that lifetime measures in vivo neuromodulator dynamics both with high temporal resolution and with consistency across animals and time. Thus, we report a method that can simultaneously measure neuromodulator change over transient and chronic time scales, promising to reveal the roles of multi–time scale neuromodulator dynamics in diseases, in response to therapies, and across development and aging.
Persistent enhancement of exciton diffusivity in CsPbBr
3
nanocrystal solids
Authors: Shcherbakov-Wu Wenbi , Saris Seryio , Sheehan Thomas John , Wong Narumi Nagaya , Powers Eric R. , Krieg Franziska , Kovalenko Maksym V. , Willard Adam P. , Tisdale William A.
Published: February 2024

In semiconductors, exciton or charge carrier diffusivity is typically described as an inherent material property. Here, we show that the transport of excitons among CsPbBr
3
perovskite nanocrystals (NCs) depends markedly on how recently those NCs were occupied by a previous exciton. Using transient photoluminescence microscopy, we observe a striking dependence of the apparent exciton diffusivity on excitation laser power that does not arise from nonlinear exciton-exciton interactions or thermal heating. We interpret our observations with a model in which excitons cause NCs to transition to a long-lived metastable configuration that markedly increases exciton transport. The exciton diffusivity observed here (>0.15 square centimeters per second) is considerably higher than that observed in other NC systems, revealing unusually strong excitonic coupling between NCs. The finding of a persistent enhancement in excitonic coupling may help explain other photophysical behaviors observed in CsPbBr
3
NCs, such as superfluorescence, and inform the design of optoelectronic devices.
Helical vasculogenesis driven by cell chirality
Authors: Zhang Haokang , Rahman Tasnif , Lu Shuhan , Adam Alejandro Pablo , Wan Leo Q.
Published: February 2024

The cellular helical structure is well known for its crucial role in development and disease. Nevertheless, the underlying mechanism governing this phenomenon remains largely unexplored, particularly in recapitulating it in well-controlled engineering systems. Leveraging advanced microfluidics, we present compelling evidence of the spontaneous emergence of helical endothelial tubes exhibiting robust right-handedness governed by inherent cell chirality. To strengthen our findings, we identify a consistent bias toward the same chirality in mouse vascular tissues. Manipulating endothelial cell chirality using small-molecule drugs produces a dose-dependent reversal of the handedness in engineered vessels, accompanied by non-monotonic changes in vascular permeability. Moreover, our three-dimensional cell vertex model provides biomechanical insights into the chiral morphogenesis process, highlighting the role of cellular torque and tissue fluidity in its regulation. Our study unravels an intriguing mechanism underlying vascular chiral morphogenesis, shedding light on the broader implications and distinctive perspectives of tubulogenesis within biological systems.
Specific codons control cellular resources and fitness
Authors: Love Aaron M. , Nair Nikhil U.
Published: February 2024

As cellular engineering progresses from simply overexpressing proteins to imparting complex phenotypes through multigene expression, judicious appropriation of cellular resources is essential. Since codon use is degenerate and biased, codons may control cellular resources at a translational level. We investigate how partitioning transfer RNA (tRNA) resources by incorporating dissimilar codon usage can drastically alter interdependence of expression level and burden on the host. By isolating the effect of individual codons’ use during translation elongation while eliminating confounding factors, we show that codon choice can trans-regulate fitness of the host and expression of other heterologous or native genes. We correlate specific codon usage patterns with host fitness and derive a coding scheme for multigene expression called the Codon Health Index (CHI, χ). This empirically derived coding scheme (χ) enables the design of multigene expression systems that avoid catastrophic cellular burden and is robust across several proteins and conditions.
Compact realization of all-attosecond pump-probe spectroscopy
Authors: Kretschmar Martin , Svirplys Evaldas , Volkov Mikhail , Witting Tobias , Nagy Tamás , Vrakking Marc J. J. , Schütte Bernd
Published: February 2024

The ability to perform attosecond-pump attosecond-probe spectroscopy (APAPS) is a longstanding goal in ultrafast science. While first pioneering experiments demonstrated the feasibility of APAPS, the low repetition rates (10 to 120 Hz) and the large footprints of existing setups have so far hindered the widespread exploitation of APAPS. Here, we demonstrate two-color APAPS using a commercial laser system at 1 kHz, straightforward post-compression in a hollow-core fiber, and a compact high-harmonic generation (HHG) setup. The latter enables the generation of intense extreme-ultraviolet (XUV) pulses by using an out-of-focus HHG geometry and by exploiting a transient blueshift of the driving laser in the HHG medium. Near-isolated attosecond pulses are generated, as demonstrated by one-color and two-color XUV-pump XUV-probe experiments. Our concept allows selective pumping and probing on extremely short timescales in many laboratories and permits investigations of fundamental processes that are not accessible by other pump-probe techniques.
Ochre-based compound adhesives at the Mousterian type-site document complex cognition and high investment
Authors: Schmidt Patrick , Iovita Radu , Charrié-Duhaut Armelle , Möller Gunther , Namen Abay , Dutkiewicz Ewa
Published: February 2024

Ancient adhesives used in multicomponent tools may be among our best material evidences of cultural evolution and cognitive processes in early humans. African
Homo sapiens
is known to have made compound adhesives from naturally sticky substances and ochre, a technical behavior proposed to mark the advent of elaborate cognitive processes in our species. Foragers of the European Middle Paleolithic also used glues, but evidence of ochre-based compound adhesives is unknown. Here, we present evidence of this kind. Bitumen was mixed with high loads of goethite ochre to make compound adhesives at the type-site of the Mousterian, Le Moustier (France). Ochre loads were so high that they lowered the adhesive’s performance in classical hafting situations where stone implements are glued to handles. However, when used as handheld grips on cutting or scraping tools, a behavior known from Neanderthals, high-ochre adhesives present a real benefit, improving their solidity and rigidity. Our findings help understand the implications of Pleistocene adhesive making.
Magnetic soft microfiberbots for robotic embolization
Authors: Liu Xurui , Wang Liu , Xiang Yuanzhuo , Liao Fan , Li Na , Li Jiyu , Wang Jiaxin , Wu Qingyang , Zhou Cheng , Yang Youzhou , Kou Yuanshi , Yang Yueying , Tang Hanchuan , Zhou Ning , Wan Chidan , Yin Zhouping , Yang Guang-Zhong , Tao Guangming , Zang Jianfeng
Published: February 2024

Cerebral aneurysms and brain tumors are leading life-threatening diseases worldwide. By deliberately occluding the target lesion to reduce the blood supply, embolization has been widely used clinically to treat cerebral aneurysms and brain tumors. Conventional embolization is usually performed by threading a catheter through blood vessels to the target lesion, which is often limited by the poor steerability of the catheter in complex neurovascular networks, especially in submillimeter regions. Here, we propose magnetic soft microfiberbots with high steerability, reliable maneuverability, and multimodal shape reconfigurability to perform robotic embolization in submillimeter regions via a remote, untethered, and magnetically controllable manner. Magnetic soft microfiberbots were fabricated by thermal drawing magnetic soft composite into microfibers, followed by magnetizing and molding procedures to endow a helical magnetic polarity. By controlling magnetic fields, magnetic soft microfiberbots exhibit reversible elongated/aggregated shape morphing and helical propulsion in flow conditions, allowing for controllable navigation through complex vasculature and robotic embolization in submillimeter regions. We performed in vitro embolization of aneurysm and tumor in neurovascular phantoms and in vivo embolization of a rabbit femoral artery model under real-time fluoroscopy. These studies demonstrate the potential clinical value of our work, paving the way for a robotic embolization scheme in robotic settings.
Lipid nanoparticles and siRNA targeting plasminogen provide lasting inhibition of fibrinolysis in mouse and dog models of hemophilia A
Authors: Strilchuk Amy W. , Hur Woosuk S. , Batty Paul , Sang Yaqiu , Abrahams Sara R. , Yong Alyssa S.M. , Leung Jerry , Silva Lakmali M. , Schroeder Jocelyn A. , Nesbitt Kate , de Laat Bas , Moutsopoulos Niki M. , Bugge Thomas H. , Shi Qizhen , Cullis Pieter R. , Merricks Elizabeth P. , Wolberg Alisa S. , Flick Matthew J. , Lillicrap David , Nichols Timothy C. , Kastrup Christian J.
Published: February 2024

Antifibrinolytic drugs are used extensively for on-demand treatment of severe acute bleeding. Controlling fibrinolysis may also be an effective strategy to prevent or lessen chronic recurring bleeding in bleeding disorders such as hemophilia A (HA), but current antifibrinolytics have unfavorable pharmacokinetic profiles. Here, we developed a long-lasting antifibrinolytic using small interfering RNA (siRNA) targeting plasminogen packaged in clinically used lipid nanoparticles (LNPs) and tested it to determine whether reducing plasmin activity in animal models of HA could decrease bleeding frequency and severity. Treatment with the siRNA-carrying LNPs reduced circulating plasminogen and suppressed fibrinolysis in wild-type and HA mice and dogs. In HA mice, hemostatic efficacy depended on the injury model; plasminogen knockdown improved hemostasis after a saphenous vein injury but not tail vein transection injury, suggesting that saphenous vein injury is a murine bleeding model sensitive to the contribution of fibrinolysis. In dogs with HA, LNPs carrying siRNA targeting plasminogen were as effective at stabilizing clots as tranexamic acid, a clinical antifibrinolytic, and in a pilot study of two dogs with HA, the incidence of spontaneous or excess bleeding was reduced during 4 months of prolonged knockdown. Collectively, these data demonstrate that long-acting antifibrinolytic therapy can be achieved and that it provides hemostatic benefit in animal models of HA.
The catabolism of lignin-derived
p
-methoxylated aromatic compounds by
Rhodococcus jostii
RHA1
Authors: Wolf Megan E. , Lalande Anne T. , Newman Brianne L. , Bleem Alissa C. , Palumbo Chad T. , Beckham Gregg T. , Eltis Lindsay D.
Published: February 2024

Emergent strategies to valorize lignin, an abundant but underutilized aromatic biopolymer, include tandem processes that integrate chemical depolymerization and biological catalysis. To date, aromatic monomers from C–O bond cleavage of lignin have been converted to bioproducts, but the presence of recalcitrant C–C bonds in lignin limits the product yield. A promising chemocatalytic strategy that overcomes this limitation involves phenol methyl protection and autoxidation. Incorporating this into a tandem process requires microbial cell factories able to transform the
p
-methoxylated products in the resulting methylated lignin stream. In this study, we assessed the ability of
Rhodococcus jostii
RHA1 to catabolize the major aromatic products in a methylated lignin stream and elucidated the pathways responsible for this catabolism. RHA1 grew on a methylated pine lignin stream, catabolizing the major aromatic monomers:
p
-methoxybenzoate (
p
-MBA), veratrate, and veratraldehyde. Bioinformatic analyses suggested that a cytochrome P450, PbdA, and its cognate reductase, PbdB, are involved in
p
-MBA catabolism. Gene deletion studies established that both
pbdA
and
pbdB
are essential for growth on
p
-MBA and several derivatives. Furthermore, a deletion mutant of a candidate
p-
hydroxybenzoate (
p
-HBA) hydroxylase, Δ
pobA
, did not grow on
p
-HBA. Veratraldehyde and veratrate catabolism required both vanillin dehydrogenase (Vdh) and vanillate
O
-demethylase (VanAB), revealing previously unknown roles of these enzymes. Finally, a Δ
pcaL
strain grew on neither
p
-MBA nor veratrate, indicating they are catabolized through the β-ketoadipate pathway. This study expands our understanding of the bacterial catabolism of aromatic compounds and facilitates the development of biocatalysts for lignin valorization.

IMPORTANCE

Lignin, an abundant aromatic polymer found in plant biomass, is a promising renewable replacement for fossil fuels as a feedstock for the chemical industry. Strategies for upgrading lignin include processes that couple the catalytic fractionation of biomass and biocatalytic transformation of the resulting aromatic compounds with a microbial cell factory. Engineering microbial cell factories for this biocatalysis requires characterization of bacterial pathways involved in catabolizing lignin-derived aromatic compounds. This study identifies new pathways for lignin-derived aromatic degradation in
Rhodococcus
, a genus of bacteria well suited for biocatalysis. Additionally, we describe previously unknown activities of characterized enzymes on lignin-derived compounds, expanding their utility. This work advances the development of strategies to replace fossil fuel-based feedstocks with sustainable alternatives.