bluuebunny/crossref_metadata_2025 huggingface dataset:
Three Delays Model applied to prevention of unsafe abortion in Ghana: a qualitative study
Authors: Otsin Mercy Nana Akua , Taft Angela J , Hooker Leesa , Black Kirsten
Published: July 2021

Background

Unsafe abortion is an important public health problem in Ghana, making significant contributions to the morbidity and mortality of reproductive-aged women. Although mostly used in explaining mortality associated with perinatal care, recent calls for research on induced abortion in Africa suggest that the Three Delays Model could be used to enhance understanding of women’s experiences and access to induced abortion care.

Methods

We conducted 47 face-to-face interviews with women who had experienced unsafe abortions, with formal abortion providers (abortion providers in hospitals) and with informal and non-legal abortion providers (pharmacy workers and herb sellers). Study participants were recruited from selected hospitals, community pharmacies and markets within the Ashanti region of Ghana. We drew on phenomenology to analyse the data.

Findings

The first delay (in seeking care) occurred because of women’s poor knowledge of pregnancy, the influence of religion, and as a result of women underestimating the seriousness of abortion complications. Factors including cost, provider attitudes, stigma, and the proximity of pharmacies to women’s homes delayed their access to safe abortion and resulted in their experience of the second delay (in reaching a healthcare facility). The third delay (in receiving appropriate care) was a result of hospitals’ non-prioritisation of abortion complications and a shortage of equipment, resulting in long hospital waiting times before treatment.

Conclusion

This study has shown the value of the Three Delays Model in illustrating women’s experiences of unsafe abortions and ways of preventing the first, second and third delays in their access to care.
Vasectomy interest and awareness among patients and their partners in prenatal clinics in the United States
Authors: Guo Xiaoyue Mona , Lore Marybeth , Madrigal Jessica , Kiley Jessica , Zumpf Katelyn , Adam Megan , Patel Ashlesha
Published: July 2021

Objective

Although vasectomy is safer, more effective and less expensive than tubal ligation, rates of permanent contraception are consistently higher in women than in men. We sought to explore vasectomy interest and awareness in patients and their partners during prenatal visits, a time when contraceptive counselling is typically performed.

Methods

Anonymous surveys were distributed between January and July 2019 to a cross-sectional, convenience sample of pregnant women and their partners, if available, presenting for outpatient prenatal care at two hospitals (one public, one private) serving different patient populations in Chicago, Illinois, USA. Survey questions gauged participant awareness and interest in vasectomies.

Results

Surveys were completed by 436 individuals (78% female, 24% male). Seventy percent of respondents indicated interest in vasectomy after achieving optimal family size, but most respondents had never discussed it with their healthcare provider. Factors associated with vasectomy interest included being partnered, having a lower household income, and knowing someone who has had a vasectomy. Almost 50% of respondents would be interested in obtaining information about vasectomies from their obstetrician or prenatal care provider.

Conclusions

Many patients and their male partners in the prenatal clinic setting were interested in vasectomy as a method for permanent contraception, but most respondents had never received counselling. Since comprehensive prenatal care includes contraceptive planning, obstetric providers are uniquely positioned to educate individuals on vasectomy.
When the factory shuts down
Authors: Borgstede Marion G , van den Broeke-Vos Majoline J W , Stevens-Stolmeijer Renate , Lameijer Heleen
Published: July 2021

Clinical introduction

A 56-year-old man without known medical history was brought to our ED after he was found next to his bed, agitated and with waxing and waning consciousness. He has been bedbound for 5 days after a long-standing period of malnutrition. Physical examination reveals Kussmaul breathing, heart rate of 62/min and blood pressure of 135/100 mm Hg, normal cardiac, abdominal and a non-focal neurological examination other than confusion and altered level of consciousness. An EKG was performed (figure 1).

Figure 1

EKG at presentation in our ED.

Question

What abnormalities are the clues to the severity of his condition? How would you confirm your suspicion?

The minimally prolonged QTc time.

The subtle horizontal ST segment elevation in V2 and V3.

The subtle positive deflection at the J point.

Nothing, this EKG is not interpretable because of the movement of baseline.
Optimal timing of cholecystectomy after necrotising biliary pancreatitis
Authors: Hallensleben Nora D , Timmerhuis Hester C , Hollemans Robbert A , Pocornie Sabrina , van Grinsven Janneke , van Brunschot Sandra , Bakker Olaf J , van der Sluijs Rogier , Schwartz Matthijs P , van Duijvendijk Peter , Römkens Tessa , Stommel Martijn W J , Verdonk Robert C , Besselink Marc G , Bouwense Stefan A W , Bollen Thomas L , van Santvoort Hjalmar C , Bruno Marco J
Published: July 2021

Objective

Following an episode of acute biliary pancreatitis, cholecystectomy is advised to prevent recurrent biliary events. There is limited evidence regarding the optimal timing and safety of cholecystectomy in patients with necrotising biliary pancreatitis.

Design

A post hoc analysis of a multicentre prospective cohort. Patients with biliary pancreatitis and a CT severity score of three or more were included in 27 Dutch hospitals between 2005 and 2014. Primary outcome was the optimal timing of cholecystectomy in patients with necrotising biliary pancreatitis, defined as: the optimal point in time with the lowest risk of recurrent biliary events and the lowest risk of complications of cholecystectomy. Secondary outcomes were the number of recurrent biliary events, periprocedural complications of cholecystectomy and the protective value of endoscopic sphincterotomy for the recurrence of biliary events.

Results

Overall, 248 patients were included in the analysis. Cholecystectomy was performed in 191 patients (77%) at a median of 103 days (P25–P75: 46–222) after discharge. Infected necrosis after cholecystectomy occurred in four (2%) patients with persistent peripancreatic collections. Before cholecystectomy, 66 patients (27%) developed biliary events. The risk of overall recurrent biliary events prior to cholecystectomy was significantly lower before 10 weeks after discharge (risk ratio 0.49 (95% CI 0.27 to 0.90); p=0.02). The risk of recurrent pancreatitis before cholecystectomy was significantly lower before 8 weeks after discharge (risk ratio 0.14 (95% CI 0.02 to 1.0); p=0.02). The complication rate of cholecystectomy did not decrease over time. Endoscopic sphincterotomy did not reduce the risk of recurrent biliary events (OR 1.40 (95% CI 0.74 to 2.83)).

Conclusion

The optimal timing of cholecystectomy after necrotising biliary pancreatitis, in the absence of peripancreatic collections, is within 8 weeks after discharge.
Methodology in phenome-wide association studies: a systematic review
Authors: Wang Lijuan , Zhang Xiaomeng , Meng Xiangrui , Koskeridis Fotios , Georgiou Andrea , Yu Lili , Campbell Harry , Theodoratou Evropi , Li Xue
Published: July 2021

Phenome-wide association study (PheWAS) has been increasingly used to identify novel genetic associations across a wide spectrum of phenotypes. This systematic review aims to summarise the PheWAS methodology, discuss the advantages and challenges of PheWAS, and provide potential implications for future PheWAS studies. Medical Literature Analysis and Retrieval System Online (MEDLINE) and Excerpta Medica Database (EMBASE) databases were searched to identify all published PheWAS studies up until 24 April 2021. The PheWAS methodology incorporating how to perform PheWAS analysis and which software/tool could be used, were summarised based on the extracted information. A total of 1035 studies were identified and 195 eligible articles were finally included. Among them, 137 (77.0%) contained 10 000 or more study participants, 164 (92.1%) defined the phenome based on electronic medical records data, 140 (78.7%) used genetic variants as predictors, and 73 (41.0%) conducted replication analysis to validate PheWAS findings and almost all of them (94.5%) received consistent results. The methodology applied in these PheWAS studies was dissected into several critical steps, including quality control of the phenome, selecting predictors, phenotyping, statistical analysis, interpretation and visualisation of PheWAS results, and the workflow for performing a PheWAS was established with detailed instructions on each step. This study provides a comprehensive overview of PheWAS methodology to help practitioners achieve a better understanding of the PheWAS design, to detect understudied or overstudied outcomes, and to direct their research by applying the most appropriate software and online tools for their study data structure.
1 Neurosurgery for severe OCD: the past, present and future
Authors: Joyce Eileen
Published: July 2021

Obsessive compulsive disorder (OCD) is a common disorder thought to have a prevalence of 1-2%. The majority of patients are helped by treatments such as exposure and response prevention therapy and medication. A significant minority fail to benefit from optimal treatment and are severely disabled with respect to everyday function.

Such patients may be candidates for a neurosurgical approach. This talk will trace the development of neurosurgery for severe OCD beginning with leucotomy/lobotomy which was practiced in the early part of the 20th Century and left an unfavourable legacy. Advancements in neurosurgery have allowed techniques such as anterior cingulotomy and anterior capsulotomy to be practiced at present and will be compared. Deep brain stimulation for severe OCD was introduced as an alternative to ablation neurosurgery but the optimal target for electrode placement remains under debate and will be discussed with reference to a study directly comparing DBS of two emerging targets within the same patients. Finally, methods of target refinement will be discussed which may improve patients outcome in the near future.
Pulse-synchronous torsional nystagmus
Authors: Milenkovic Ivan , Sycha Thomas , Berger-Sieczkowski Evelyn , Rommer Paulus , Czerny Christian , Wiest Gerald
Published: July 2021

Purely torsional spontaneous nystagmus almost always has a central vestibular cause. We describe a man with spontaneous pulse-synchronous torsional nystagmus in which the clockwise component corresponded to his pulse upswing, in keeping with a peripheral vestibular cause; following imaging we diagnosed left-sided superior canal dehiscence syndrome. Identifying pulse synchronicity of spontaneous nystagmus may help to distinguish central from peripheral vestibular torsional nystagmus, and is readily confirmed at the bedside using Frenzel’s glasses and a pulse oximeter.
Bayesian estimation of soil-water characteristic curves
Authors: Zhang J. , Yang S. , Zhang L.L. , Zhou M.L.
Published: July 2021

The soil-water characteristic curve (SWCC) is a significant prerequisite for studying the mechanical properties of unsaturated soil. As experimental measurement of the SWCC is time-consuming, empirical methods have been suggested to estimate the SWCC. However, the uncertainty associated with SWCC can be substantial. In this paper, a hybrid method based on Bayes’ theorem is suggested to estimate the SWCC, where an empirical method can be used to provide prior knowledge about the SWCC, and a limited quantity of measured data are used to update the SWCC. The Bayesian model is then solved with a Markov Chain Monte Carlo simulation. Through the suggested method, the valuable information provided by the empirical method can be combined with the measurement data. The suggested method can not only provide the best estimate about the SWCC, but also account for the associated uncertainty. Also, the effect of more measured points on the estimation of SWCC can be quantified. The suggested method provides a practical means to estimate the SWCC using a limited amount of data.
Physical impact of thermo-diffusion and diffusion-thermo on Marangoni convective flow of hybrid nanofluid (MnZiFe2O4–NiZnFe2O4–H2O) with nonlinear heat source/sink and radiative heat flux
Authors: Song Ying-Qing , Khan M. Ijaz , Qayyum Sumaira , Gowda R. J. Punith , Kumar R. Naveen , Prasannakumara B. C. , Elmasry Yasser , Chu Yu-Ming
Published: July 2021

The objective of this study is to illustrate the influence of Marangoni convection, nonlinear heat sink/source, thermal radiation, viscous dissipation, activation energy, Soret and Dufour effects on magnetohydrodynamics flow of nanofluid generated by rotating disk. Further, the entropy generation equation is derived as a function of velocity, concentration, and thermal gradients. The governing equations of the model along with associated boundary constraints are reduced to ordinary differential equations by adopting suitable similarity transformation. Later, these equations are tackled numerically by means of shooting technique. The whole examination is performed by using two distinctive nanoparticles of ferrites in particular, manganese zinc ferrite (MnZnFe2O4) and nickel zinc ferrite (NiZnFe2O4) in a carrier liquid [Formula: see text]. The physical characteristics of velocity, thermal, concentration entropy generation, skin friction, and Nusselt number against numerous pertinent parameters are discussed in detail and deliberated graphically. Result reveals that thermal gradient shows substantial enhancement for advanced values of heat sink/source parameter. The entropy production increases with an augmentation in the Brinkman number and Marangoni ratio values. The escalation in Marangoni ratio and Dufour number improves the rate of heat transference.
Spectral analysis of dispersive shocks for quantum hydrodynamics with nonlinear viscosity
Authors: Lattanzio Corrado , Zhelyazov Delyan
Published: July 2021

In this paper, we investigate spectral stability of traveling wave solutions to 1D quantum hydrodynamics system with nonlinear viscosity in the [Formula: see text], that is, density and velocity, variables. We derive a sufficient condition for the stability of the essential spectrum and we estimate the maximum modulus of eigenvalues with non-negative real part. In addition, we present numerical computations of the Evans function in sufficiently large domain of the unstable half-plane and show numerically that its winding number is (approximately) zero, thus giving a numerical evidence of point spectrum stability.
Fluid evolution along the Patterson Lake corridor in the southwestern Athabasca Basin: constraints from fluid inclusions and implications for unconformity-related uranium mineralization
Authors: Rabiei M. , Chi G. , Potter E. G. , Tschirhart V. , MacKay C. , Frostad S. , McElroy R. , Ashley R. , McEwan B.
Published: July 2021

The Patterson Lake corridor (PLC) in the southwestern margin of the Athabasca Basin hosts several high-grade uranium deposits. These deposits are located in the basement up to 900 m below the unconformity surface, raising questions about their affiliation with typical unconformity-related uranium (URU) deposits elsewhere in the basin. Based on cross-cutting relationships four pre- and three syn- to post-mineralization quartz generations were identified. Fluid inclusion analyses indicate that pre-mineralization fluids have salinities ranging from 0.2 to 27.2 wt% NaCl equiv. (avg. 9.0 wt%), whereas syn-mineralization fluids have salinities ranging from 8.8 to 33.8 wt% NaCl + CaCl
2
(avg. 25.4 wt%), with NaCl- and CaCl
2
-rich varieties. The homogenization temperatures (
T
h
) of fluid inclusions from pre-mineralization quartz range from 80 to 244°C (avg. 147°C), and from syn-mineralization quartz range from 64 to 248°C (avg. 128°C). Fluid boiling is indicated by the co-development of liquid-dominated and vapour-dominated fluid inclusions within individual fluid inclusion assemblages from the syn-mineralization quartz and is related to episodic fluid pressure drops caused by reactivation of basement faults. Our results indicate that composition and
P
–
T
conditions of the ore fluids in the PLC are comparable to those of typical URU deposits in the Athabasca Basin, indicating that the uranium deposits in the PLC formed under similar hydrothermal conditions. Episodic reactivation of basement faults was an important driving force to draw uraniferous fluids from the basin and reducing fluids from the basement to the mineralization sites, forming deep basement-hosted deposits.

Supplementary material:
Table 1, microthermometric results of type-2 and -5 fluid inclusion assembladges and isolated inclusions from the Patterson Lake corridor, and table 2, microthermometric results of type-6 fluid inclusions from the Patterson Lake corridor are available at
https://doi.org/10.6084/m9.figshare.c.5510179

Thematic collection:
This article is part of the Uranium Fluid Pathways collection available at:
https://www.lyellcollection.org/cc/uranium-fluid-pathways
Fast Search of Lightweight Block Cipher Primitives via Swarm-like Metaheuristics for Cyber Security
Authors: Jin Xin , Duan Yuwei , Zhang Ying , Huang Yating , Li Mengdong , Mao Ming , Singh Amit Kumar , Li Yujie
Published: July 2021

With the construction and improvement of 5G infrastructure, more devices choose to access the Internet to achieve some functions. People are paying more attention to information security in the use of network devices. This makes lightweight block ciphers become a hotspot. A lightweight block cipher with superior performance can ensure the security of information while reducing the consumption of device resources. Traditional optimization tools, such as brute force or random search, are often used to solve the design of Symmetric-Key primitives. The metaheuristic algorithm was first used to solve the design of Symmetric-Key primitives of SKINNY. The genetic algorithm and the simulated annealing algorithm are used to increase the number of active S-boxes in SKINNY, thus improving the security of SKINNY. Based on this, to improve search efficiency and optimize search results, we design a novel metaheuristic algorithm, named particle swarm-like normal optimization algorithm (PSNO) to design the Symmetric-Key primitives of SKINNY. With our algorithm, one or better algorithm components can be obtained more quickly. The results in the experiments show that our search results are better than those of the genetic algorithm and the simulated annealing algorithm. The search efficiency is significantly improved. The algorithm we proposed can be generalized to the design of Symmetric-Key primitives of other lightweight block ciphers with clear evaluation indicators, where the corresponding indicators can be used as the objective functions.
Improving the Smoothed Complexity of FLIP for Max Cut Problems
Authors: Bibak Ali , Carlson Charles , Chandrasekaran Karthekeyan
Published: July 2021

Finding locally optimal solutions for
MAX-CUT
and

MAX-
k
-CUT

are well-known PLS-complete problems. An instinctive approach to finding such a locally optimum solution is the FLIP method. Even though FLIP requires exponential time in worst-case instances, it tends to terminate quickly in practical instances. To explain this discrepancy, the run-time of FLIP has been studied in the smoothed complexity framework. Etscheid and Röglin (ACM Transactions on Algorithms, 2017) showed that the smoothed complexity of FLIP for
max-cut
in arbitrary graphs is quasi-polynomial. Angel, Bubeck, Peres, and Wei (STOC, 2017) showed that the smoothed complexity of FLIP for
max-cut
in complete graphs is (
O
Φ
5
n
15.1
), where Φ is an upper bound on the random edge-weight density and Φ is the number of vertices in the input graph.

While Angel, Bubeck, Peres, and Wei’s result showed the first polynomial smoothed complexity, they also conjectured that their run-time bound is far from optimal. In this work, we make substantial progress toward improving the run-time bound. We prove that the smoothed complexity of FLIP for
max-cut
in complete graphs is
O
(Φ
n
7.83
). Our results are based on a carefully chosen matrix whose rank captures the run-time of the method along with improved rank bounds for this matrix and an improved union bound based on this matrix. In addition, our techniques provide a general framework for analyzing FLIP in the smoothed framework. We illustrate this general framework by showing that the smoothed complexity of FLIP for
MAX-3-CUT
in complete graphs is polynomial and for
MAX
-
k
-
CUT
in arbitrary graphs is quasi-polynomial. We believe that our techniques should also be of interest toward showing smoothed polynomial complexity of FLIP for
MAX
-
k
-
CUT
in complete graphs for larger constants
k
.
Driver Behavior-aware Parking Availability Crowdsensing System Using Truth Discovery
Authors: Zhu Yi , Gupta Abhishek , Hu Shaohan , Zhong Weida , Su Lu , Qiao Chunming
Published: July 2021

Spot-level parking availability information (the availability of each spot in a parking lot) is in great demand, as it can help reduce time and energy waste while searching for a parking spot. In this article, we propose a crowdsensing system called SpotE that can provide spot-level availability in a parking lot using drivers’ smartphone sensors. SpotE only requires the sensor data from drivers’ smartphones, which avoids the high cost of installing additional sensors and enables large-scale outdoor deployment. We propose a new model that can use the parking search trajectory and final destination (e.g., an exit of the parking lot) of a single driver in a parking lot to generate the probability profile that contains the probability of each spot being occupied in a parking lot. To deal with conflicting estimation results generated from different drivers, due to the variance in different drivers’ parking behaviors, a novel aggregation approach SpotE-TD is proposed. The proposed aggregation method is based on truth discovery techniques and can handle the variety in Quality of Information of different vehicles. We evaluate our proposed method through a real-life deployment study. Results show that SpotE-TD can efficiently provide spot-level parking availability information with a 20% higher accuracy than the state-of-the-art.
Discrete Fréchet Distance under Translation
Authors: Bringmann Karl , KüNnemann Marvin , Nusser André
Published: July 2021

The discrete Fréchet distance is a popular measure for comparing polygonal curves. An important variant is the discrete Fréchet distance under translation, which enables detection of similar movement patterns in different spatial domains. For polygonal curves of length
n
in the plane, the fastest known algorithm runs in time Õ(
n
5
) [12]. This is achieved by constructing an arrangement of disks of size Õ(
n
4
), and then traversing its faces while updating reachability in a directed grid graph of size
N
:= Õ(
n
5
), which can be done in time Õ(√
N
) per update [27]. The contribution of this article is two-fold.

First, although it is an open problem to solve dynamic reachability in directed grid graphs faster than Õ(√
N
), we improve this part of the algorithm: We observe that an offline variant of dynamic
s
-
t
-reachability in directed grid graphs suffices, and we solve this variant in amortized time Õ(
N
1/3
) per update, resulting in an improved running time of Õ(
N
4.66
) for the discrete Fréchet distance under translation. Second, we provide evidence that constructing the arrangement of size Õ(
N
4
) is necessary in the worst case by proving a conditional lower bound of
n
4 - o(1)
on the running time for the discrete Fréchet distance under translation, assuming the Strong Exponential Time Hypothesis.
An Efficient Classification Algorithm for Traditional Textile Patterns from Different Cultures Based on Structures
Authors: Ngo Vuong M. , Duong Thuy-Van T. , Nguyen Tat-Bao-Thien , Nguyen Phuong T. , Conlan Owen
Published: July 2021

Textiles have an important role in many cultures and have been digitised. They are three-dimensional objects and have complex structures, especially archaeological fabric specimens and artifact textiles created manually by traditional craftsmen. In this article, we propose a novel algorithm for textile classification based on their structures. First, a hypergraph is used to represent the textile structure. Second, multisets of
k
-neighbourhoods are extracted from the hypergraph and converted to one feature vector for representation of each textile. Then, the
k
-neighbourhood vectors are classified using seven most popular supervised learning methods. Finally, we evaluate experimentally the different variants of our approach on a data set of 1,600 textile samples with the 4-fold cross-validation technique. The experimental results indicate that comparing the variants, the best classification accuracies are 0.999 with LR, 0.994 with LDA, 0.996 with KNN, 0.994 with CART, 0.998 with NB, 0.974 with SVM, and 0.999 with NNM.
Multiple-source Data Collection and Processing into a Graph Database Supporting Cultural Heritage Applications
Authors: Origlia Antonio , Rossi Silvia , Martino Sergio Di , Cutugno Francesco , Chiacchio Maria Laura
Published: July 2021

The continuous growth of available resources on the web, both in the form of Linked Open Data and on Social Networks, provides an important opportunity to gather information concerning specific kinds of touristic activities like, for example, cultural tourism, eco-tourism, bike-tourism, and so on. Both decision makers and tourists can take advantage from these data, as demonstrated by previous works, with institutional actors foreseeing an increase in the use of this data to substitute other time-consuming and expensive approaches. However, managing multiple sources built with different goals and structures is not straightforward, so specific design choices must be made when assembling this kind of information. Graph databases represent an ideal way to combine multiple-source data but, to be successful, strategies accounting for inconsistencies and format differences have to be defined to support coherent analysis. Also, the continuously changing nature of crowd-sourced data makes it difficult, for the research community, to compare technological approaches to the different tasks that are linked to cultural heritage, from recommendation to management. To support the research effort in this direction, we describe the data ingestion and enrichment procedure we followed to organise knowledge coming from three different sources, namely Wikidata, Wikipedia, and Flickr, into a single, application-oriented, resource organised as a graph database. We present the potential use of this resource to perform multiple source analyses targeting the specific case of cultural tourism on a nationwide scale, and we propose its use as a shared benchmark for technological applications designed to support optimal management of cultural resources.
Investigation of Single Image Depth Prediction Under Different Lighting Conditions
Authors: Frisky Aufaclav Zatu Kusuma , Harjoko Agus , Awaludin Lukman , Zambanini Sebastian , Sablatnig Robert
Published: July 2021

This article investigates the limitations of single image depth prediction (SIDP) under different lighting conditions. Besides that, it also offers a new approach to obtain the ideal condition for SIDP. To satisfy the data requirement, we exploit a photometric stereo dataset consisting of several images of an object under different light properties. In this work, we used a dataset of ancient Roman coins captured under 54 different lighting conditions to illustrate how the approach is affected by them. This dataset emulates many lighting variances with a different state of shading and reflectance common in the natural environment. The ground truth depth data in the dataset was obtained using the stereo photometric method and used as training data. We investigated the capabilities of three different state-of-the-art methods to reconstruct ancient Roman coins with different lighting scenarios. The first investigation compares the performance of a given network using previously trained data to check cross-domains performance. Second, the model is fine-tuned from pre-trained data and trained using 70% of the ancient Roman coin dataset. Both models are tested on the remaining 30% of the data. As evaluation metrics, root mean square error and visual inspection are used. As a result, the methods show different characteristic results based on the lighting condition of the test data. Overall, they perform better at 51° and 71° angles of light, so-called ideal condition afterward. However, they perform worse at 13° and 32° because of the high density of shadows. They also cannot reach the best performance at 82° caused by the reflection that appears on the image. Based on these findings, we propose a new approach to reduce the shadows and reflections on the image using intrinsic image decomposition to achieve a synthetic ideal condition. Based on the results of synthetic images, this approach can enhance the performance of SIDP. For some state-of-the-art methods, it also achieves better results than previous original RGB images.
A New Infectious Unit: Extracellular Vesicles Carrying Virus Populations
Authors: Kerviel Adeline , Zhang Mengyang , Altan-Bonnet Nihal
Published: July 2021

Viral egress and transmission have long been described to take place through single free virus particles. However, viruses can also shed into the environment and transmit as populations clustered inside extracellular vesicles (EVs), a process we had first called vesicle-mediated en bloc transmission. These membrane-cloaked virus clusters can originate from a variety of cellular organelles including autophagosomes, plasma membrane, and multivesicular bodies. Their viral cargo can be multiples of nonenveloped or enveloped virus particles or even naked infectious genomes, but egress is always nonlytic, with the cell remaining intact. Here we put forth the thesis that EV-cloaked viral clusters are a distinct form of infectious unit as compared to free single viruses (nonenveloped or enveloped) or even free virus aggregates. We discuss how efficient and prevalent these infectious EVs are in the context of virus-associated diseases and highlight the importance of their proper detection and disinfection for public health.
Multi-Dimensional Fuzzy Graphene Bioelectronic Actuators
Authors: Garg Raghav , Rashid Reem , San Roman Daniel , Wang Yingqiao , Stang Maria , Feinberg Adam , Rivnay Jonathan , Cohen-Karni Tzahi
Published: July 2021

The ability to manipulate the electrophysiology of electrically active cells and tissues has enabled a deeper understanding of healthy and diseased states. This has primarily been achieved via bioelectronic actuators that interface engineered materials with biological entities. Graphene has gained recent interest as a building-block for bioelectronic actuators due to its advantageous electrochemical properties and biocompatibility. However, functional graphene bioelectronics exhibit a two-dimensional (2D) topology. This leads to inherent performance limitations due to the limited exposed surface-area and poor interactions with interfaced cells and tissues. Ideal geometry of graphene-based actuators needs to leverage the material’s high surface-area-to-volume ratio to facilitate maximum interaction with the electrode.

Here we report a breakthrough three-dimensional (3D) topology of graphene: nanowire templated 3D fuzzy graphene (NT-3DFG), for actuation of electrically active cells and tissues. Using a bottom-up approach, we synthesize an interconnected network of free-standing graphene flakes on Si nanowires (SiNWs). The 3D topology leads to enhanced surface-area compared to planar surfaces allowing NT-3DFG microelectrodes to exhibit lower electrode impedance. The increased surface area also leads to an increase of up to 5-fold and 10-fold in the cathodic charge storage capacity (CSCC) and the charge injection capacity (CIC), respectively, for 20 µm NT-3DFG compared to 20 µm conventional Pt electrodes. To enhance the electrical actuation capabilities of NT-3DFG, we electrodeposit poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) on the 3D electrodes. This results in further enhancement in the exhibited CSCC and CIC thus enabling further miniaturization of graphene-based microelectrodes to ultra-microelectrodes for functional bioelectronics. Our results demonstrate the importance of extending the topology of nanomaterials to 3D to push the physical and functional limits of conventional bioelectronics.
(Invited) Quantification of NO Concentration Via Changes in Single Walled Carbon Nanotube Fluorescence
Authors: Iverson Nicole M , Meier Jakob , Stapleton Joseph , Hofferber Eric , Haworth Abigail , Kachman Stephen
Published: July 2021

Nitric oxide (NO) is a reactive nitrogen species that is involved in both positive and negative processes in biological systems. Researchers have been unable to agree on the correlation between NO concentration and disease progression, possibly because of NO’s short half-life and the difficulty of determining concentration with current NO sensors. Single walled carbon nanotubes (SWNT), when wrapped in single-stranded (AT)15, act as a fluorescence sensor for NO. Unfortunately, the correlation between NO concentration and the SWNT’s fluorescence intensity has been difficult to determine due to the fact that the final SWNT fluorescence intensity does not directly correlate to NO concentration and an inability to immobilize the sensor without altering its properties. Through the use of a recently developed sensor platform, systematic studies have been conducted to determine the correlation between changes in SWNT fluorescence and NO concentration. The methods used to determine equations that convert SWNT fluorescence into NO concentration will be presented, providing a method to quantify extracellular NO concentration and a blueprint for the development of equations to transform changes in SWNT fluorescence into concentrations for other reactive species.
Protein-Nanotube Sensing Devices: Site-Specific Coupling for the Detection of Active Antimicrobial Resistance Components
Authors: Xu Xinzhao , Bowen Benjamin J , Gwyther Rebecca E.A. , Freeley Mark , Grigorenko Bella , Nemukhin Alexander , Eklöf-Österberg Johnas , Moth-Poulsen Kasper , Jones Dafydd D , Palma Matteo
Published: July 2021

A central challenge in nanobiotechnology is the bottom-up assembly of platforms capable of monitoring and exploiting biomolecular interactions with nanoscale control; this in turn can allow the development of novel bioelectronics interfaces. In this regard, electrical detection methodologies, using nanomaterials, are one of the most promising candidates for biosensing investigations: they can be effectively merged with miniaturised hardware, offer simplicity, low-cost, portability, ultrahigh sensitivity, selectivity, and (label-free) real-time electrical detection

We will present the fabrication of bioelectronic devices for the development of real-time biosensors with engineered protein interfacing. In particular, we assembled b-lactamase (BL) inhibitory proteins (BLIPs) onto SWCNT sidewalls in electronic device configurations, with controlled protein orientation. This allowed us to control the local electrostatic surface presented within the Debye length (see Figure), and thus modulate the conductance gating effect upon sensing protein targets. We recorded the current responses in real-time for the detection of a range of concentrations of a class BL enzymes, that degrade antibiotics, in the context of investigating antimicrobial resistance (AMR). The strategy presented here is of general applicability for the control and detection of protein-protein interactions in nanoscale device configurations, through electrostatic surface profiling; moreover, it may open up new opportunities for the development of AMR-related diagnostic devices.

Figure 1
Three-Dimensional Graphene Microelectrode Arrays for Detection of Wound Healing Biomarkers
Authors: San Roman Daniel , Garg Raghav , Wang Yingqiao , Behun Marissa , Brown Bryan , Badylak Stephen , Cohen-Karni Tzahi
Published: July 2021

Volumetric muscle loss (VML) injuries, such as those from high-energy trauma or tumor ablation, often result in scar tissue formation and permanent loss of skeletomuscular function. Directly after VML injury formation, neutrophils and macrophages arrive at the wound site, releasing cytokines and growth factors to allow proliferation and innervation. Monitoring the wound healing process by spatially mapping key regulatory wound biomarkers, such as nitric oxide (NO), can elucidate the state of the wound and thus inform critical clinical interventions. While single-point NO probes with sufficient performance for short-term measurements have been produced previously, improvements in device sensitivity, stability, and the number of sensing nodes are needed for in vivo applications. Here we leverage novel nanomaterials and their exceptional electrochemical properties to construct three-dimensional fuzzy graphene (3DFG) microelectrode arrays (MEAs) for the multiplexed electrochemical sensing of NO. We report in vitro results for 3DFG MEAs capable of selectively detecting NO (versus known interferents such as nitrite, ascorbic acid, and uric acid) at physiological concentrations in the nanomolar regime (limit of detection < 10 nM). Future work will entail in vivo NO detection to aid in monitoring wound states in animal models.
Developing Ovarian Cancer Sensors Using Molecular Perceptron
Authors: Yaari Zvi A , Yang Yoona , Jagota Anand , Zheng Ming , Heller Daniel A.
Published: July 2021

Ovarian cancer patient prognosis and quality of life are significantly affected by the failure to accurately diagnose disease at early stage. Currently, less than 15% of ovarian cancer patients are diagnosed at stage 1, when 5-year survival rates are near 93%. Early detection may save more than 80% of women diagnosed with ovarian cancer. Our goal is to develop clinical long-term implantable carbon nanotube-based sensors for ovarian cancer biomarkers to transiently detect and monitor their levels in patients. The proposed sensors will harness the unique optical properties and sensitivity of single-walled carbon nanotubes. To improve sensitivity and specificity of such sensors, previously developed to detect ovarian cancer biomarkers in vivo, we used molecular perceptron—data analytics-based methods to detect specific spectroscopic fingerprints from the binding of protein biomarkers to the nanotube surface.
(Invited) In Situ Study on Nucleation and Growth of Single-Walled Carbon Nanotubes on Catalysts
Authors: Li Yan , Yang Feng
Published: July 2021

Understanding the growth mechanism is prerequisite to design the methodology for controlled growth of single-walled carbon nanotubes (SWNTs). By using an environmental aberration-corrected transmission electron microscope in combination with in situ synchrotron X-ray absorption spectroscopy, we directly present the structural and composition evolution of cobalt and cobalt-tungsten intermetallic catalysts during the nucleation and growth of SWCNTs under carbon feeding. The co-existence of cobalt and cobalt carbide was generally observed among the pure cobalt catalysts which are active in nucleating tubes. The nucleation and growth behaviors of tubes on solid state cobalt nanoparticles and molten ones have been compared. It was found that the tubes grown from solid state catalysts always present smaller diameter than the catalysts. No structure-correlation between catalyst and nanotube was found. Distinct different from cobalt, no carbides or carbon diffusion induced structural change was observed from the in situ characterization. The atomic structure of Co7W6 was stable when CNTs nucleating. These observations reveal that cobalt-tungsten intermetallic catalysts act as the stable structure template for the chirality controlled growth of SWNTs.
(Invited) Globally Aligned, Wafer-Scale Deposition of Carbon Nanotubes Via Interfacial Assembly
Authors: Arnold Michael S.
Published: July 2021

Floating evaporative self-assembly (FESA) is a solution-based technique for fabricating highly-aligned semiconducting carbon nanotube films.1,2 Field-effect transistors (FETs) based on carbon nanotubes aligned via FESA have exhibited current densities exceeding that of GaAs and Si, demonstrating the promise of this technique.3 However, the global uniformity of FESA films is poor, as the films are composed of stripes of aligned and randomly oriented carbon nanotubes. Additionally, this technique is inherently difficult to scale. In the work presented here, we demonstrate a scalable technique to overcome the shortcomings of FESA and to achieve globally uniform films of aligned carbon nanotubes at desirable packing densities for FETs.

In our technique, carbon nanotubes are continuously aligned across target substrates by lifting the substrates through a flowing nanotube ink/water interface. The ink/water interface collects and confines the nanotubes, which is vital to achieving a high degree of alignment. Polarized Raman spectroscopy mapping is used to quantify the degree of alignment in the resulting aligned nanotube films. The full width at half maximum (FWHM) of the alignment distribution within the films is 6.0° measured across a 1 mm2 area. We control the aligned carbon nanotube packing density from 0.2 to 59 µm-1 by varying the ink concentration from 0.1 to 100 µg mL-1. Using optimized conditions, we demonstrate the scalability of this technique by aligning carbon nanotubes across a 100 mm wide wafer. Charge transport measurements are performed using FETs with the aligned carbon nanotube films as the active channels, and the performance is compared to FETs based on FESA films.

1. Jinkins, K., R. et al. Nanotube Alignment Mechanism in Floating Evaporative Self-Assembly. Langmuir 33, 13407–13414 (2017).

2. Joo, Y., Brady, G. J., Arnold, M. S. & Gopalan, P. Dose-Controlled, Floating Evaporative Self-assembly and Alignment of Semiconducting Carbon Nanotubes from Organic Solvents. Langmuir 30, 3460–3466 (2014).

3. Brady, G. J. et al. Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs. Sci. Adv. 2, (2016).
(Invited) Supramolecular Chemistry-Based One-Pot Separation of Solubilizer-Free Pure Semiconducting Single-Walled Carbon Nanotubes: Molecular Strategy and Mechanism
Authors: Nakashima Naotoshi , Fukuzawa Masashi , Nishimura Kanako , Hashimoto Wataru , Fujigaya Tsuyohiko , Kato Yuichi , Staykov Aleksandar
Published: July 2021

We summarize a supramolecular chemistry-based one-pot, and highly efficient separation of a solubilizer/adsorbent-free pure semiconducting SWCNT (sc-SWCNT) using flavin/isoalloxazine analogues with different substituents. On the basis of both experimental and computational simulations (DFT study), we have revealed the molecular requirements of the solubilizers as well as provided a possible mechanism for such a highly efficient selective sc-SWCNT separation[1]. We introduced thio-substituents at 7- and 8-positions of a flavin analogue, which allows for coordination of metal ions. Based on both experimental and theoretical methods, we have demonstrated that the formed Cu2+-based supramolecular assembled complex shows very high selective sorting of semiconducting single-walled carbon nanotubes with (8,6)- and (9,4)-chiralities[2]. The present sorting methods are very simple (one-pot) and gives a promising sc-SWCNT separation methodology.

References

[1] N. Nakashima, M. Fukuzawa, K. Nishimura, T. Fujigaya, Y. Kato, A. Staykov, “Supramolecular chemistry-based one-pot high-efficient separation of solubilizer-free pure semiconducting single-walled carbon nanotubes: molecular strategy and mechanism”, J. Am. Chem. Soc.
2020, 142, 11847-11856

[2] A. Staykov, W. Hashimoto, F. Toshimitsu, N. Nakashima, “A Flavin-Cu2+ Supramolecular Complex for Highly Selective Sorting of Semiconducting Single-walled Carbon Nanotubes with Specific Chiralities, ChemComm. 2020, 56, 12415-12418
(Invited) Progress in Using Carbon Nanotube Spectra for Mechanical Strain Sensing
Authors: Meng Wei , Bachilo Sergei M. , Nagarajaiah Satish , Weisman R. Bruce
Published: July 2021

A characteristic property of semiconducting single-wall carbon nanotubes (SWCNTs) is distinct near-infrared photoluminescence following excitation by visible light. Theory and experiment show that these optical emission peaks shift predictably in wavelength as nanotubes are compressed or stretched along their axis. We are exploiting this effect in a powerful new method intended for measuring mechanical strain in critical infrastructure components such as airframes, pressurized vessels, pipelines, support beams, etc. The method involves applying a dilute dispersion of nanotubes in a polymeric host onto the surface of the specimen to form a sub-micron thick film in which SWCNTs act as strain sensors. This layer is overcoated with a transparent protective top coat such as a polyurethane varnish. Subsequent strains in the substrate are transmitted to the nanotubes by load transfer. The substrate strain magnitude and direction are then measured by illuminating the surface at any point of interest with a small visible laser beam and spectrally analyzing the resulting near-IR nanotube emission. Single-point measurements currently provide strain magnitude resolution of ca. 50 microstrain, strain angle resolution of ca. 5 degrees, and spatial resolution of ca. 50 mm. Each reading takes less than one second, allowing compilation of strain maps from scanned data. Unlike digital image correlation, which is currently the only commercial non-contact strain technology, the new method can measure strains accumulated when the specimen is not under observation. It thus has the potential for routine use in industrial structural health monitoring as well as in testing and development laboratories. Results will be presented showing strain measurements in metallic, plastic, and concrete specimens. We will also describe recent progress in adapting the technology to camera-based measurements using spectrally resolved fluorescence imaging.
(Invited) High-Purity Infrared Single Photons Generation with Carbon Nanotubes Coupled to a Microcavity
Authors: Borel Antoine , Claude Théo , Chassagneux Yannick , Lauret Js , He Xiaowei , Doorn Stephen , Voisin Christophe
Published: July 2021

Single photon emission in the near infrared was recently reported in individual carbon nanotubes, either plain or functionalized, with however a moderate quantum yield.

Here we use a tunable fiber cavity to enhance light-matter interaction, using the so-called Purcell effect to boost the performances of the single photon source in view of applications in quantum telecommunications. Preferential excitation conditions building on localized excited states, both for plain and functionalized nanotubes, are considered and the performances of the sources in terms of purity, brightness and indistinguishability are discussed.