bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpersonal connection
Authors: Laing James
Published: September 2023

We are social animals that seek to connect with others of our kind. However, this common thought stands in need of elaboration. In this article, I argue for three theses. First, that we pursue certain forms of communicative interaction for their own sake insofar as they are ways of connecting with another. Second, that interpersonal connection is a metaphysically primitive emotional relation which resists reductive analysis in terms of the states of individuals. And finally, that our desire for interpersonal connection has a strong claim to being explanatorily and normatively prior to our desires for mutual‐attachment, interpersonal belonging and approbation.
Obesity alters immunopathology in cancers and inflammatory diseases
Authors: Zhang Xiaofen , Gao Li , Meng Haiyang , Zhang Ailing , Liang Yan , Lu Jingli
Published: September 2023

Obesity is characterized by chronic low‐grade inflammation and is strongly associated with multiple immunological diseases, including cancer and inflammatory diseases. Recent animal studies revealed that obesity‐induced immunological changes worsen immune‐driven diseases and cause resistance to immunotherapy. Here, we discuss the role of obesity in the immunopathology and treatment responses of cancers, respiratory and allergic diseases, and IL‐17‐mediated inflammatory diseases. We summarize the unique features of the inflammatory state of these diseases, which are orchestrated by obesity. In particular, obesity alters the immune landscape in cancers with a reprogrammed metabolic profile of tumor‐infiltrating immune cells. Obesity exacerbates airway inflammation by dysregulating multiple immune‐cell subsets. Obesity also dysregulates Th17, IL‐17‐producing mucosal‐associated invariant T (MAIT), and γδ T cells, which contribute to IL‐17‐mediated inflammatory response in multiple sclerosis, inflammatory bowel disease, psoriasis, atopic dermatitis, and rheumatoid arthritis. By identifying the effects of obesity on immunological diseases, new strategies could be devised to target immune dysregulation caused by obesity.
Looking for relief: Developing and testing the emotion‐regulation explanation of selective exposure to political information
Authors: Kiil Filip
Published: September 2023

Though selective exposure is immensely important for the functioning of democracy, no consensus exists as to its cause. The most frequently assumed causal explanation is cognitive dissonance avoidance, but direct empirical tests of this explanation are incredibly rare and have generally not been supportive. Furthermore, although cognitive dissonance avoidance concerns regulation of emotional states, this explanation has not yet been integrated with the newest research on emotion‐regulation processes and their role in shaping political attitudes and behavior. I perform such a theoretical integration and derive testable implications of the emotion‐regulation account of the role of cognitive dissonance in shaping selective exposure. I test these together with expectations derived from an alternative explanation (informational utility), in two, original, preregistered survey experiments with 4864 U.S. adults combined. I consistently find support for the emotion‐regulation account in experimental tests and in two out of three observational analyses. The alternative explanation of informational utility finds support in observational analyses, but not in the experimental tests. The study provides the first experimental evidence linking emotion regulation and selective exposure and suggests that people do, indeed, select like‐minded sources to downregulate negative emotion.
Safety and efficacy of one and two booster doses of SARS‐CoV‐2 mRNA vaccines in kidney transplant recipients: A randomized clinical trial
Authors: Drenko Petr , Kacer Martin , Kielberger Lukas , Vlas Tomas , Topolcan Ondrej , Kucera Radek , Reischig Tomas
Published: September 2023

Background

Kidney transplant recipients are at risk for a severe course of COVID‐19 with a high mortality rate. A considerable number of patients remains without a satisfactory serological response after the baseline and adjuvant SARS‐CoV‐2 vaccination schedule.

Methods

In this prospective, randomized study, we evaluated the efficacy and safety of one and two booster doses of mRNA vaccines (either mRNA‐1273 or BNT162b2) in 125 COVID‐19 naive, adult kidney transplant recipients who showed an insufficient humoral response (SARS‐CoV‐2 IgG <10 AU/ml) to the previous 2‐dose vaccination schedule. The primary outcome was the difference in the rate of a positive antibody response (SARS‐CoV‐2 IgG ≥10 AU/ml) between one and two booster doses at 1 month after the final booster dose.

Results

A positive humoral response was observed in 36 (62%) patients receiving two booster doses and in 28 (44%) patients receiving one booster dose (odds ratio [OR], 2.10, 95% confidence interval [CI], 1.02–4.34, p = .043). Moreover, median SARS‐CoV‐2 IgG levels were higher with two booster doses (p = .009). The number of patients with positive virus neutralizing antibody (VNA) levels was numerically higher with two booster doses compared to one booster dose, but without statistical significance (66% vs. 50%, p = .084). There was no significant difference in positive seroconversions rate and antibody levels between mRNA‐1273 and BNT162b2.

Conclusion

A higher number of kidney transplant recipients achieved a positive antibody response after two booster doses compared to one booster dose.

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A Combined Delayed Detached Eddy Simulation and Linearized Navier–Stokes Equation Study on the Generation and Reduction of Aerodynamic Noises Inside Steam Turbine Control Valve With Acoustic Liner
Authors: Tang Yuchao , Wang Peng , Liu Yingzheng
Published: September 2023

This study was aimed at numerically investigating the source, generation mechanism, and strategy for reducing aerodynamic noises inside a steam turbine control valve. A delayed detached eddy simulation was performed to extract the three-dimensional unsteady turbulent flow structures formed within the serpentine flow passage of the turbine valve. Acoustic analogies, spatial Fourier transform, and spectral proper orthogonal decomposition on the delayed detached eddy simulation-simulated flow data were complementarily combined to clarify the generation mechanism of tonal and broadband aerodynamic noises. The results showed that broadband noises were produced by wall-attached jet flow and turbulent mixing flow between the annular wall jets and central reverse flow. High-intensity tonal noises were generated by the excitation of multi-order natural acoustic modes of the bell-shaped valve spindle. The intensive acoustic pressure pulsations concentrated inside the bell jar and propagated along the diffuser to the downstream turbine chamber. A novel ring acoustic liner was designed using the acoustic impedance model to reduce the valve noises without sacrificing the flow performance. The noise reduction effectiveness was evaluated by solving the linearized Navier–Stokes equations in the frequency domain.
Identification of the glycopeptide epitope recognized by a protective
Cryptosporidium
monoclonal antibody
Authors: Bhalchandra Seema , Gevers Koen , Heimburg-Molinaro Jamie , van Roosmalen Mark , Coppens Isabelle , Cummings Richard D. , Ward Honorine D.
Published: September 2023

Cryptosporidium
species are a leading cause of pediatric diarrheal disease and death in low- and middle-income countries and pose a particular threat to immunocompromised individuals. As a zoonotic pathogen,
Cryptosporidium
can have devastating effects on the health of neonatal calves. Despite its impact on human and animal health, consistently effective drug treatments for cryptosporidiosis are lacking and no vaccine is available. We previously showed that
C. parvum
mucin-like glycoproteins, gp40, and gp900 express an epitope identified by a monoclonal antibody 4E9. 4E9 neutralized
C. parvum
infection
in vitro
as did glycan-binding proteins specific for the Tn antigen (GalNAc-α1-S/T). Here, we show that 4E9 ameliorates disease
in vivo
in a calf challenge model. The 4E9 epitope is present on
C. hominis
in addition to
C. parvum
gp40 and gp900 and localizes to the plasma membrane and dense granules of invasive and intracellular stages. To characterize the epitope recognized by 4E9, we probed a glycan array containing over 500 defined glycans together with a custom-made glycopeptide microarray containing glycopeptides from native mucins or
C. parvum
gp40 and gp15. 4E9 exhibited no binding to the glycan array but bound strongly to glycopeptides from native mucins or gp40 on the glycopeptide array, suggesting that the antibody epitope contains both peptide and glycan moieties. 4E9 only recognized glycopeptides with adjacent S or T residues in the motif S*/T*-
X-
S*/T* where
X
= 0 or 1. These data define the 4E9 epitope and have implications for the inclusion of the epitope in the development of vaccines or other immune-based therapies.
Plasmid-mediated drug resistance in mycobacteria: the tip of the iceberg?
Authors: Derbyshire Keith M. , Salfinger Max
Published: September 2023

Macrolides, such as clarithromycin, are crucial in the treatment of nontuberculous mycobacteria (NTM). NTM are notoriously innately drug resistant, which has made the dependence on macrolides for their treatment even more important. Not surprisingly, resistance to macrolides has been documented in some NTM, including
Mycobacterium avium
and
Mycobacterium abscessus
, which are the two NTM species most often identified in clinical isolates. Resistance is mediated by point mutations in the 23S ribosomal RNA or by methylation of the rRNA by a methylase (encoded by an
erm
gene). Chromosomally encoded
erm
genes have been identified in many of the macrolide-resistant isolates, but not in
Mycobacterium chelonae
. Now, Brown-Elliott et al. (J Clin Microbiol 61:e00428-23, 2023,
https://doi.org/10.1128/JCM.00428-23
) describe the identification of a new
erm
variant,
erm
(55)
,
which was found either on the chromosome or on a plasmid in highly macrolide-resistant clinical isolates of
M. chelonae
. The chromosomal
erm
(55) gene appears to be associated with mobile elements; one gene is within a putative transposon and the second is in a large (37 kb) insertion/deletion. The plasmid carrying
erm
(55) also encodes type IV and type VII secretion systems, which are often linked on large mycobacterial plasmids and are hypothesized to mediate plasmid transfer. While the conjugative transfer of the
erm
(55)-containing plasmid between NTM has yet to be demonstrated, the inferences are clear, as evidenced by the dissemination of plasmid-mediated drug resistance in other medically important bacteria. Here, we discuss the findings of Brown-Elliott et al.
,
and the potential ramifications on treatment of NTM infections.
Highly divergent CRESS DNA and picorna-like viruses associated with bleached thalli of the green seaweed
Ulva
Authors: van der Loos Luna M. , De Coninck Lander , Zell Roland , Lequime Sebastian , Willems Anne , De Clerck Olivier , Matthijnssens Jelle
Published: September 2023

Marine macroalgae (seaweeds) are important primary producers and foundation species in coastal ecosystems around the world. Seaweeds currently contribute to an estimated 51% of the global mariculture production, with a long-term growth rate of 6% per year, and an estimated market value of more than US$11.3 billion. Viral infections could have a substantial impact on the ecology and aquaculture of seaweeds, but surprisingly little is known about virus diversity in macroalgal hosts. Using metagenomic sequencing, we characterized viral communities associated with healthy and bleached specimens of the commercially important green seaweed
Ulva
. We identified 20 putative new and divergent viruses, of which the majority belonged to the Circular Rep-Encoding Single-Stranded (CRESS) DNA viruses [single-stranded (ss)DNA genomes],
Durnavirales
[double-stranded (ds)RNA], and
Picornavirales
(ssRNA). Other newly identified RNA viruses were related to the
Ghabrivirales
, the
Mitoviridae
, and the
Tombusviridae
. Bleached
Ulva
samples contained particularly high viral read numbers. While reads matching assembled CRESS DNA viruses and picorna-like viruses were nearly absent from the healthy
Ulva
samples (confirmed by qPCR), they were very abundant in the bleached specimens. Therefore, bleaching in
Ulva
could be caused by one or a combination of the identified viruses but may also be the result of another causative agent or abiotic stress, with the viruses simply proliferating in already unhealthy seaweed tissue. This study highlights how little we know about the diversity and ecology of seaweed viruses, especially in relation to the health and diseases of the algal host, and emphasizes the need to better characterize the algal virosphere.

IMPORTANCE

Green seaweeds of the genus
Ulva
are considered a model system to study microbial interactions with the algal host. Remarkably little is known, however, about viral communities associated with green seaweeds, especially in relation to the health of the host. In this study, we characterized the viral communities associated with healthy and bleached
Ulva
. Our findings revealed the presence of 20 putative novel viruses associated with
Ulva
, encompassing both DNA and RNA viruses. The majority of these viruses were found to be especially abundant in bleached
Ulva
specimens. This is the first step toward understanding the role of viruses in the ecology and aquaculture of this green seaweed.
Parallel evolution of linezolid-resistant
Staphylococcus aureus
in patients with cystic fibrosis
Authors: Pitcher Nicholas J. , Feder Andries , Bolden Nicholas , Zirbes Christian F. , Pamatmat Anthony J. , Boyken Linda , Hill Jared J. , Bartels Alyssa R. , Thurman Andrew L. , Reeb Valerie C. , Porterfield Harry S. , Moustafa Ahmed M. , Planet Paul J. , Fischer Anthony J.
Published: September 2023

Linezolid is an antibiotic used to treat serious
Staphylococcus aureus
infections. Resistance to linezolid is considered rare but could emerge with repeated dosing. We recently reported widespread prescription of linezolid for a cohort of patients with cystic fibrosis (CF). The goals of this study were to determine the incidence of linezolid-resistant methicillin-resistant
Staphylococcus aureus
(MRSA) in CF and identify molecular mechanisms for linezolid resistance. We identified patients who cultured
S. aureus
resistant to linezolid with minimum inhibitory concentration (MIC) >4 at the University of Iowa CF Center between 2008 and 2018. We obtained isolates from these patients and retested susceptibility to linezolid using broth microdilution. We used whole genome sequencing to perform phylogenetic analysis of linezolid-resistant isolates and examine sequences for mutations or accessory genes that confer linezolid resistance. Between 2008 and 2018, 111 patients received linezolid, and 4 of these patients cultured linezolid-resistant
S. aureus
. We sequenced 11 resistant and 21 susceptible isolates from these 4 subjects. Phylogenetic analysis indicated that linezolid resistance developed in ST5 or ST105 backgrounds. Three individuals had linezolid-resistant
S. aureus
with a G2576T mutation in 23S rRNA. One of these subjects additionally had a

mutS
−
mutL
−

hypermutating
S. aureus
that produced five resistant isolates with multiple ribosomal subunit mutations. In one subject, the genetic basis for linezolid resistance was unclear. We conclude that linezolid resistant
S. aureus
can occur through multiple genetic mechanisms in patients with repeated exposure to this antibiotic.

IMPORTANCE

Patients with cystic fibrosis have persistent lung infections with
Staphylococcus aureus
that require extensive antibiotic treatments. Linezolid, an antibiotic given by oral or intravenous route, is prescribed repeatedly for patients whose lung disease has progressed. After treatment with linezolid,
S. aureus
strains can evolve antibiotic resistance through multiple genetic mechanisms. In addition to a common mutation in the 23S ribosomal RNA known to confer linezolid resistance,
S. aureus
strains can evolve novel resistance based on a combination of mutations affecting the bacterial ribosome. This combination of mutations was observed in a strain that exhibited hypermutation owing to the loss of the DNA repair genes
mutS
and
mutL
. In this cohort of patients with cystic fibrosis, linezolid resistance was transient, possibly due to the growth disadvantage of resistant strains. However, ongoing chronic exposure to linezolid may create optimal conditions for the future emergence of resistance to this critical antibiotic.
Nanomechanical/Micromechanical Approach to the Problems of Dendrochronology and Dendroclimatology
Authors: Golovin Yu. I. , Samodurov A. A. , Gusev A. A. , Tyurin A. A. , Golovin D. Yu. , Vasyukova I. A. , Yunak M. A.
Published: September 2023

The most widespread approach in dendrochronology (wood dating) and dendroclimatology (climate reconstruction) is based on measurement of the width of annual growth rings by analyzing optical images of wood cross sections. This approach is quite efficient and easy to implement but it has inherent drawbacks. Raw data for these techniques originate from the optical properties of the wood surface, which are not directly related to other properties of wood, mechanical properties in particular. This paper describes a new quantitative approach applicable to dendrochronology and dendroclimatology based upon measurement of the micromechanical properties of wood by employing nanoindendation and digital sclerometry. It yields not only the width of annual growth rings and early and late wood layers with an accuracy not inferior to optical methods, but also rich data on the mechanical properties of the wood with a high spatial resolution that could be brought to subcellular scale if necessary. This data can be used for the dendrochronological analysis of archeological finds and the evaluation of climatic parameters during tree growth with a time resolution of up to a month or even better, which is unlike other common methods with a time resolution of one year. Moreover, the detailed continuous profiling of local mechanical properties can form a basis for improving our understanding of the nature and mechanisms of the formation of macromechanical properties important for applications and can clarify the climate factors that have the greatest impact on such properties.
Prevalence of neck pain and its associated factors in Africa: a systematic review and meta-analysis protocol
Authors: Mukhtar Naziru Bashir , Ibrahim Aminu Alhassan , Mohammed Jibril
Published: September 2023

Introduction

Neck pain is one of the most prevalent musculoskeletal pain conditions with multifactorial impact including pain, disability and reduced quality of life. To the best of our knowledge, no systematic review and meta-analysis is available to provide reliable data on the pooled prevalence of neck pain and its associated factors in Africa. Thus, the objective of this study is to describe a protocol for a systematic review and meta-analysis on the prevalence of neck pain and its associated factors in Africa.

Methods

This systematic review protocol has been designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). A systematic search will be conducted among six key electronic databases including PubMed/MEDLINE, Scopus, African Journals Online, EMBASE, CINAHL and Web of Science, from inception onwards. Population-based cross-sectional studies reporting prevalence of neck pain in the African continent will be included. The primary outcome will be the prevalence of neck pain, whereas the secondary outcomes will be the factors associated with neck pain prevalence. Two independent reviewers will screen the titles/abstracts and relevant full-text articles of potentially relevant studies. Data from eligible studies will be extracted using a customised data extraction form. The risk of bias and methodological quality of the included studies will be assessed using the Newcastle–Ottawa Scale and critical appraisal tool, respectively. A narrative synthesis will be used to summarise the prevalence estimates of neck pain and associated factors. However, if feasible, random-effects meta-analysis will be conducted with Revman V.5.4 software. Additionally, subgroup, sensitivity and publication bias analyses will be conducted.

Discussion

This will be the first systematic review and meta-analysis to systematically identify and synthesise available literature on the prevalence of neck pain and its associated factors in Africa. The results of this review may assist health professionals and policymakers to plan and implement evidence-based strategies that will lessen the burden of neck pain.

Ethics and dissemination

Data from previously published studies will be collected and analysed and hence ethical approval will not be sought for this study. The results of this review will be disseminated through publication in a peer-reviewed academic journal and presentation at relevant academic conferences.

PROSPERO registration number

CRD42021273585.
Anisotropic dark energy universe in f(Q, T) gravity with observational constraints
Authors: Solanke Y.S. , Kale A.P. , Pawar D.D. , Dagwal V.J.
Published: September 2023

Aim of this paper is to investigate an anisotropic locally rotationally symmetric (LRS) Bianchi type-I space–time in the context of the recently proposed f( Q, T) gravity, where Q is the non-metricity scalar and T is energy–momentum tensor. We have considered f( Q, T) = α Q + β T a linear form, where α and β are model parameters. We have analyzed the exact solution of LRS Bianchi type-I space–time by assuming relation between metric potential A = B n , where n is arbitrary non-zero real number. To study the anisotropic nature of the dynamical dark energy, we assume that the skewness parameters are time dependent and n ≠ 1. We have constrained to our model by using observational Hubble dataset. Onwards, discussed the physical behavior of cosmological parameters such as energy density, pressure, EoS parameter, deceleration parameter and, Energy conditions.
Design of quasiperiodic magnetic superlattices and domain walls supporting bound states
Authors: Castillo-Celeita Miguel , Contreras-Astorga Alonso , Fernández C. David J.
Published: September 2023

We study the simplest Lamé magnetic superlattice in graphene, finding its allowed and forbidden energy bands and band-edge states explicitly. Then, we design quasiperiodic magnetic superlattices supporting bound states using Darboux transformations. This technique enables us to add any finite number of bound states, which we exemplify with the most straightforward cases of one and two bound states in the designed spectrum. The topics of magnetic superlattices and domain walls in gapped graphene turn out to be connected by a unitary transformation in the limit of significantly large oscillation periods. We show that the generated quasiperiodic magnetic superlattices are also linked to domain walls, with the bound states keeping their nature in such a limit.
Studying Developer Eye Movements to Measure Cognitive Workload and Visual Effort for Expertise Assessment
Authors: Aljehane Salwa D. , Sharif Bonita , Maletic Jonathan I.
Published: September 2023

Eye movement data provides valuable insights that help test hypotheses about a software developer's comprehension process. The pupillary response is successfully used to assess mental processing effort and attentional focus. Relatively little is known about the impact of expertise level in cognitive effort during programming tasks. This paper presents a quantitative analysis that compares the eye movements of 207 experts and novices collected while solving program comprehension tasks. The goal is to examine changes of developers' eye movement metrics in accordance with their expertise. The results indicate significant increase in pupil size with the novice group compared to the experts, explaining higher cognitive effort for novices. Novices also tend to have a significant number of fixations and higher gaze time compared to experts when they comprehend code. Moreover, a correlation study found that programming experience is still a powerful indicator when explaining expertise in this eye-tracking dataset among other expertise variables.
A Comparative Study and Analysis of Various Interconnects for Very Large-Scale Integration
Authors: Susaritha M.
Published: September 2023

Various interconnects utilised in very large-scale integration in this work. The expanding use of portable devices has increased the demand for low-power circuit design. Sub-threshold circuits are the greatest option to address the demand for even more-low power. However, decreased performance and increased variability are the main problems with sub-threshold circuits. Furthermore, global interconnects have a significant impact on the performance and power dissipation of sub-threshold circuits. For future VLSI circuit applications, interconnect is a brand-new and very promising alternative that has to have its propagation latency and stability analysed in order to substantiate its claim that it can replace existing interconnect designs.
(Invited) Tuning and Optimizing Photo- and Electroluminescence from Sorted and Functionalized Single-Walled Carbon Nanotubes
Authors: Zaumseil Jana
Published: September 2023

The integration of semiconducting single-walled carbon nanotubes (SWNTs) into optoelectronic devices requires them to be in contact with substrate surfaces, with each other in networks or arrays and with a surrounding medium, such as a dielectric, electrolyte or even other semiconductors (e.g., acceptors, donors, wrapping polymer). These interactions have a direct impact on the spectroscopic properties of SWNTs, e.g., by excitation transfer, changing exciton energies, promoting trion emission or by inducing emissive or non-emissive defect states. Here, I will discuss the impact of intentionally and unintentionally introduced defects in SWNT networks on their carrier density dependent photoluminescence and electroluminescence spectra and how to optimize and tune these effects in light-emitting devices. I will also highlight the role of the surrounding dielectric for the localization of charge carriers and suppression/enhancement of trion emission.
(Invited) Optical Investigation of Single Nanographenes
Authors: Liu Thomas , Medina Lopez Daniel , Osella Silvio , Levy-Falk Hugo , Rondin Loïc , Beljonne David , Campidelli Stephane , Lauret Js
Published: September 2023

Carbon based light emitters ranging from small organic molecules to carbon nanotubes have been subject of a great attention in the framework of diverse applications such as optoelectronics, bio-imaging, and quantum technologies. In this context, graphene quantum dots (GQD) whose size is between that of small polycyclic aromatic hydrocarbon molecules and of carbon nanotubes, have important assets. In particular the complete control of the structure allowed by their synthesis through bottom-up chemistry opens the way to a wide customization of their electronic, optical, and spin properties [1-3].

The full benefit from these opportunities requires addressing GQD’s intrinsic photophysical properties. To do so, single molecule photoluminescence experiment is a powerful tool [4-6]. Nevertheless, until now, GQDs faced a problem of solubility that has complexified both the study of their intrinsic properties and their use for applications. In this presentation, we will report on the study of new structures that show a quasi-perfect solubility. We will show how this breakthrough allows us studying in depth their photophysics. Finally, we will see that the theoretical predictions of the evolution of the electronic properties of the GQDs with their structure are fully confirmed by the experiments.

[1] M. G. Debije, J. Am. Chem. Soc. 2004, 126, 4641

[2] X. Yan, X. Cui, and L.-s. Li, J. Am. Chem. Soc. 2010 132, 5944

[3] A. Konishi et al, J. Am.
Chem. Soc. 2010, 132, 11021

[4] S. Zhao et al, Nature Communications, 2018, 9, 3470

[5] T. Liu et al, Nanoscale, 14, 3826 – 3833 (2022)

[6] T. Liu et al, Journal of Chemical Physics 156, 104302 (2022)

[7] D. Medina-Lopez et al, in preparation
(Invited) Quantum Defects as Sensors
Authors: Wang YuHuang
Published: September 2023

Organic color-centers are molecularly tunable quantum defects that can be synthetically introduced into semiconducting carbon nanotube hosts. Charge carriers in the form of electron-hole pairs (or excitons) are efficiently harvested at these atomic defect sites to emit as bright shortwave-infrared photons that carry local chemical information. These intriguing properties open new possibilities of pushing the limits of sensing and imaging. In this talk, we will discuss recent advances as well as the challenges and opportunities at this emerging frontier.
(Invited) Multiphysics Model of the sSNOM Spectroscopy: Can Near-Field Probes Report the Spectrum of Nanomaterials?
Authors: Rotkin Slava V.
Published: September 2023

Last decade has been celebrated with a substantial increase of publications on imaging of nanomaterials with near-field probes. The latter include Tip-Enhanced Raman and/or Photoluminescence Spectroscopy (TERS/TEPL), various near-infrared (NIR) Atomic Force Microscopy (AFM) based methods, and several scattering Scanning Near-field optical methods (sSNOM). Using various coherent sources, often tunable in terms of excitation, these methods produce high spatial resolution images – near-field scanning maps, in terms of a pixel size claimed to be limited only by the size of the scanning tip.

By design, TERS/TEPL detects a spectral response at each point of a map, which is, naively speaking, gives us a local probe of optical material properties within a single pixel (at the fixed excitation wavelength). NIR-AFM and sSNOM (leaving aside the FTIR mode) allow to obtain quasi-spectral information by tweaking the excitation. In this case, the collected (elastic) signal is restricted to the wavelength of the excitation.

The essence of the near-field method is in breaking the laws of a plane-wave reflection from the sample, which requires a sub-wavelength separation between the tip and the sample and a strong enough near-field coupling between those. Still, it is routinely assumed that the tip is an “ideal probe” and its role is to “channel” the information about the local optical response to the detector. Up to date, little is known about the spectral response of the tip-sample system from the perspective of quantum physics.

In this work, several aspects of the problem: mechanical motion of the scanning tip, electrodynamics of the excitation/scattered light, and quantum solid state description of the sample
and
the tip – are combined to obtain, within a simple model, a full picture of the near-field detection. The results, though not general and limited by the simplicity of model used for the sake of clarity of derivation, shed the light on the spectral response of a typical near-field microscope and describe effects, earlier called “artifacts”, as natural response for coupled tip-sample elementary excitations. Lastly, an application of the model for an analysis of spectra of nBN heteronanotubes (Y. Feng, et.al, ACS Nano 15, 5600, 2021) will be presented.

Acknowledgement: This work has been partially supported by NSF MRSEC (DMR-2011839).

Fig. 1. (left) Amplitude and phase of the near-field optical signal vs. the optical frequency: S(ω). (right) Same optical amplitude and phase vs. ω and the phase of mechanical motion of an AFM tip.

Figure 1
(Invited) On-the-Fly Non-Adiabatic Dynamics Simulations of Single-Walled Carbon Nanotubes with Covalent Defects
Authors: Tretiak Sergei
Published: September 2023

Single-walled carbon nanotubes (SWCNTs) with covalent surface defects have been explored recently due to their promise for use in single-photon telecommunication emission and in spintronic applications. The dynamical evolution of excitons (the primary electronic excitations) in these systems has only been loosely explored using atomistic modeling due to the size-limitations of these large systems. We present computational modeling of non-radiative relaxation on a variety of SWCNT chiralities with single-defect functionalization schemes. Our modeling uses a trajectory surface hopping algorithm accounting for excitonic effects with a configuration interaction approach. We find a strong chirality and defect-composition dependence on the population relaxation (50 – 500 fs) between the nanotube band-gap excitation and the defect-associated, single-photon-emitting state, giving insight into the dynamic trapping nature of these localized excitonic states. Engineering fast population decay into the quasi-two-level sub-system with weak coupling to higher-energy states increases the effectiveness and controllability of these quantum light emitters.
(Invited) Quantifying Long-Range Exciton Energy Transfer in Carbon Nanotube Polariton Microcavities
Authors: Arnold Michael S.
Published: September 2023

In Ref. 1 and at the Spring 2022 ECS B03 Symposium on Carbon Nanotubes, we reported on the long-range energy transfer of excitons from (6,5) to (7,5) carbon nanotubes across an insulating barrier in an optical microcavity, mediated by moderate and strong exciton-photon polariton coupling and measured via two-dimensional, white-light spectroscopy. This talk will present on the alternative use of nanotube-C60 photovoltaic devices embedded in microcavities to quantify the efficiency of this long-range energy transfer and the factors that affect it.

[1] Energy cascades in donor-acceptor exciton-polaritons observed by ultrafast two-dimensional white-light spectroscopy, M. Son, Z.T. Armstrong, R.T Allen, A. Dhavamani, M.S. Arnold, M.T. Zanni, Nature Communications 13, 7305 (2022). DOI: 10.1038/s41467-022-35046-2
(Invited) Anisotropy in Complex Refractive Index Spectra of Single-Chirality-Enriched Carbon Nanotube Films
Authors: Wu Hengkai , Nishihara Taishi , Takakura Akira , Matsuda Kazunari , Tanaka Takeshi , Kataura Hiromichi , Miyauchi Yuhei
Published: September 2023

Toward macroscopic applications of exceptional optical properties of single-walled carbon nanotubes (SWCNTs), we reported in-plane complex refractive index spectra [1] of various single-chirality-enriched [2] SWCNTs films in which the SWCNTs are mostly oriented in two dimensions parallel to the film surface. However, in order to describe the anisotropic optical responses of such SWCNT films for incident light from all the directions, out-of-plane refractive index spectra are also required, in addition to the in-plane ones. We will report complete broadband complex refractive index spectra of single-chirality-enriched SWCNTs films for in-plane and out-of-plane optical responses. [1] T. Nishihara, A. Takakura, M. Shimasaki, K. Matsuda, T. Tanaka, H. Kataura, and Y. Miyauchi, Nanophotonics 11, 1011 (2022). [2] Y. Yomogida, T. Tanaka, M. Zhang, M. Yudasaka, X. Wei, and H. Kataura, Nat. Commun. 7, 12056 (2016).
Laser Fluence Dependent Modulation of Single Walled Carbon Nanotube Photoluminescence
Authors: Bakh Naveed Ali , Gong Xun , Silmore Kevin S. , Lee Michael Andrew , Salem Daniel , Koman Volodymyr B. , Nguyen Freddy , Strano Michael S.
Published: September 2023

Single-walled carbon nanotubes (SWCNT) have a unique, non-photobleaching, bandgap photoluminescence (PL) that has been of interest for sensor development. Take advantage of these properties, colloidal dispersions of single SWCNTs in aqueous solvents are often formed by creating a surface corona phase (CP) using amphiphilic materials. As SWCNT PL emission following photoexcitation can be significantly dependent on its local environment, the CP can be used to tune its photophysical properties, often as a design parameter for sensor development. Recent sensor experiments have shown that reporting and controlling laser excitation can be a method to significantly reduce measurement variability. In this work, we study this phenomenon of excitation fluence (EF) (mW/area) dependent PL modulation for aqueous dispersed SWCNTs. By using a continuously stirred chamber excited at a single location, the stirring rate can be a means of controlling SWCNT excitation exposure. SWCNT wrapped in both DNA and SDS SWCNT CPs showed a decreased quantum yield of nearly 40% with increasing EF while those with sodium cholate and phospholipid-PEG CPs remain invariant. Through spectroscopy and heat transfer modeling, we determined that the observed effect is unlikely to have a significant direct local solution heating contribution from SWNCT photoabsorption. Finally, we used previously studied SWCNT sensor constructs, for ascorbic acid and dopamine, to show how EF can affect calibration and eventual sensor applications. This work highlights the importance of measuring, testing, reporting and controlling for EF while developing SWCNT based photophysical sensors. This newly characterized property can also serve as a unique parameter to tune optical responsivity.
Conductance of Metallic Carbon Nanotubes Network
Authors: Adinehloo Davoud , Mojibpour Ali , Gao Weilu , Kono Junichiro , Perebeinos Vasili
Published: September 2023

The conductance of the carbon nanotubes (CNTs) network incorporates intertube and intratube conductance. Using the Anderson and tight-binding models, we calculate both conductances in the armchair and chiral metallic CNTs. We found that, at room temperature, the intertube conductance dominates in CNTs with larger localization lengths. Intertube conductance includes electronic and phonon-assisted junction conductance. We have revealed that the electronic conductance of a relaxed structure is around an order of magnitude larger than an unrelaxed structure. We found that the phonon-assisted conductance of armchair CNTs is comparable with their electronic conductance. However, the phonon-assisted conductance of chiral CNTs is around seven times smaller than the electronic conductance due to the large momentum needed for momentum relaxation. Furthermore, we address the dependence of junction conductance on the angle between the CNTs, the twist angle and sliding shift of the CNTs, the Fermi energy, and the applied bias voltage between CNTs. Our calculations perfectly match the experimentally measured temperature-dependent conductance using a single geometrical fitting parameter.
(Third Place Poster Award) Synthesis and Characterization of Block Copolymer Dispersants for Semiconducting Single-Walled Carbon Nanotubes
Authors: Oliveras Santos Stephanie , Li Songying (Frederick) , Arnold Michael Scott , Gopalan Padma
Published: September 2023

To leverage the full potential of the outstanding electronic properties of semiconducting single-walled carbon nanotubes (s-CNTs), it is essential to disperse and sort high purity s-CNTs from a heterogeneous mixture. Due to the inherent insolubility of CNTs, various organic dispersing agents that non-covalently interact with CNTs have been successfully used. These dispersants include small molecule surfactants and aromatic compounds, conjugated polymers, DNA, and polyelectrolytes. Of the macromolecular dispersants, polymers with conjugated backbones are widely studied because they can wrap around or strongly adsorb on CNTs to create very stable dispersions in organic solvents. Most of these conjugated polymers are based on polythiophenes or polyfluorenes, which depending on the structure and composition can sort specific chiralities of s-CNTs with over 99.99% semiconducting purity.

In this work, we explore conjugated polymer-based block copolymers for sorting and dispersing s-CNTs. Non-conjugated block copolymer-based dispersants have been reported by us and others with varying degrees of success in aqueous and organic solvents. Here we present our recent studies on the synthesis of ABA triblock copolymer-based CNT dispersants where B is the conjugated block and A is the non-conjugated block. The synthesis of the ABA triblock can be achieved by separately synthesizing the rod segments and the coil segments, each with reactive chain end functionalities, and then coupling the rod segments with the coil segments via reaction of the chain ends using, for example, a click reaction. Alternatively, the rod segment or the coil segment can be synthesized first and used as a macroinitiator for the polymerization of the other segment. Each of these two methods offers some advantages and disadvantages. A series of these ABA triblocks with fixed B block length and varying A block lengths were synthesized and evaluated for their ability to sort and disperse ArcD and HiPCO CNTs. A second series of ABA triblocks with fixed A block lengths but increasing B block lengths were also synthesized. We will present the challenges associated with the synthesis and purification of these block copolymer dispersants. As the middle-conjugated B block wraps around the CNTs, we anticipate the two peripheral A blocks to interact with the organic solvent toluene to further solubilize the CNTs. Our studies show that the presence of the A blocks significantly increases the sorting efficiency while preserving the chirality selectiveness of the B block. As the length of the B block increases, the sorting yields can be significantly improved as well. We further discuss the role of the dispersity of the B block if any on the dispersion of s-CNTs.
(Invited) Flexible Resistive Random-Access Memories Based on Carbon Nanotubes and Their Application for Reservoir Computing
Authors: Ohno Yutaka
Published: September 2023

Reservoir computing (RC) is one of the machine learning methods derived from a recurrent neural network (RNN) and has attracted attention because of the small amount of computation required for learning. In recent years, various forms of physical RC using nonlinear physical systems such as memristors, optical amplifiers, and soft octopus robots have been proposed for low power consumption and high-speed processing. [1] The physical reservoir system needs non-linearity, high dimensionality, and short-term memory. It has also been shown that transient response currents due to electrochemical reactions and ion migration in solution have the ability of reservoirs [2]. In this study, we report carbon nanotube (CNT)-based resistive random-access memories (ReRAMs) and their application for reservoir computing.

The network-like CNT film is used as electrodes sandwiching a thin (10 nm) HfO2 oxide film to form CNT/HfO2/CNT ReRAMs. The CNT film was synthesized using the floating-catalyst chemical vapor deposition method. Then, the CNT film was transferred onto a plastic substrate. HfO2 was deposited by the atomic layer deposition method onto CNT film. Finally, another layer of CNT film was transferred to form CNT/HfO2/CNT stack. The ReRAM exhibited clear memory behavior with SET and REST voltages around +6 V and –6 V, respectively. The ReRAM can sustain the current level of each state for more than 1 × 104 s and can be predicted to store them for ten years. The ReRAMs also exhibited stable operation under bending stress with a 0.5 cm bending radius.

We used the ReRAMs as a reservoir for reservoir computing. A time-series prediction task called NARMA10, which was often used as a benchmark of reservoir computing, was performed with a normalized mean square error (NMSE) of 0.38. The chaotic motion of a double pendulum was also successfully demonstrated by using the CNT ReRAM-based reservoir.

[1] G. Tanaka et al., Neural Netw. 115, 100 (2019), [2] S. Kan et al., Adv. Sci. 9, 2104076 (2022)
Radial Alignment of Carbon Nanotubes Via Dead-End Filtration
Authors: Rust Christian , Schill Elias , Li Han , Spari Manuel , Guttmann Markus , Bacher Andreas , Garrity Oisín , Reich Stephanie , Flavel Benjamin S
Published: September 2023

Dead-end filtration is a facile method to globally align single wall carbon nanotubes (SWCNTs) in large area films with a two-dimensional order parameter, , approaching unity. Uniaxial alignment has been achieved using pristine and hot-embossed membranes but more sophisticated geometries have yet to be investigated. In this work, we create three different patterns with radial symmetry and an area of 3.8 cm². Two of these patterns are replicated by the filtered SWCNTs and values of » 0.85 are obtained. Each of the radially aligned SWCNT films are characterized by scanning cross-polarized microscopy in reflectance and laser imaging in transmittance with linear, radial and azimuthal polarized light fields. The former is used to define a novel indicator akin to the two-dimensional order parameter using Malu’s law, yielding 0.82 for the respective film. The films are then transferred to a flexible printed circuit board and terminal two-probe electrical measurements are conducted to explore the potential of those new alignment geometries.

Figure 1
(Invited) Single-Walled Carbon Nanotubes Charge Management by Controlled Functionalization
Authors: Reich Stephanie , Setaro Antonio , Fiebor Alphonse , Adeli Mohsen
Published: September 2023

Managing the density of charges in carbon nanotubes opens new ways to tune their optical response, their transport properties, and their physico-chemical features. Charge transfer from molecules adsorbed onto the sidewall or filled within the hollow cavity of the nanotubes has already been demonstrated, yet a fine-tunable control of the surface coverage/filling fraction (and thus the amount of transferred charge) remains challenging to achieve. Alternatively, we developed an optically non-perturbing covalent functionalisation technique based on the inclusion of a triazine derivative into the carbon network. The nitrogen atom sustaining the attached group becomes an integrated part of the π-conjugated network and contributes with its lone electron pair to uplifting the position of the Fermi level of the tube. Since the density of attached groups can be varied by adapting the synthetic conditions, this technique offers the advantage of controlling the amount of charge injected into the tubes. Here we focus on a novel class of charge-transfer agents that either donate or withdraw electrons depending on the arrangements of their building units and how they affect the tubes features.
(Invited) Understanding Chemical Doping and Transport in Dispersions of Isolated Carbon Nanotubes
Authors: Ferguson Andrew , Earley Justin , Murrey Tucker , Reid Obadiah , Rumbles Garry , Blackburn Jeff
Published: September 2023

Recently we demonstrated that the chemical structure of the redox charge-carrier dopant plays a significant role in the delocalization and transport properties of the injected charge-carriers in networks of enriched semiconducting single-walled carbon nanotubes (s-SWCNT). Here, we seek to gain a deeper understanding of the charge-carrier doping and transport processes for isolated polymer-wrapped s-SWCNT in a low dielectric constant solution-phase environment. We compare solution-phase s-SWCNT samples in toluene that are p-type doped by either 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4-TCNQ) or (2,3,4,5,6-pentafluoro)benzyloxy-substituted icosahedral dodecaborane cluster (DDB-F60). We show that DDB-F60 is a more potent charge-carrier dopant than F4-TCNQ at low concentrations but that the ultimate injected hole charge-carrier density is limited by the large size of the DDB-F60 counteranion, due to saturation of the carbon nanotube surface area that is accessible to the dopant molecules. Using a non-contact spectroscopy technique in the microwave frequency region (ca. 9 GHz), we show that the holes injected by DDB-F60 are more delocalized and mobile, consistent with calculations that suggest a smaller coulombic binding energy between the hole on the carbon nanotube and the electron on the DDB-F60 counteranion. However, samples doped by F4-TCNQ reach a higher peak conductance than is achieved by DDB-F60 doping, where the conductance in the latter case is limited by the maximum achievable hole charge-carrier density and hole scattering processes that reduce the carrier mobility at high hole densities. Our observations point to the need to understand the subtle balance between the carrier-counterion interactions and the injected charge-carrier density to optimize charge-carrier transport in chemically doped s-SWCNT systems.