bluuebunny/crossref_metadata_2025 huggingface dataset:
Nasal sill augmentation: an overlooked concept in rhinoplasty—a technical note and review of the literatures
Authors: Adham Gholamhossein , Keyhan Seied Omid , Fallahi Hamid Reza , Ziaei Heliya , Thomas Mohan
Published: May 2021

Background

Nasal sill is one of the components of the alar ring, affecting the esthetic outcomes of rhinoplasty; accordingly, we developed a novel technique to adjust defects in this area and compared it with the available techniques.

Methods

Our technique was based on creating a tunnel access to the nasal sill area through an incision made in the lower third of the columella using the open approach or through a nostril base incision in patients, who underwent alar base reduction, followed by insertion of a cartilaginous graft into the marked defect area.

Results

A total number of 54 patients with a defect in the nasal sill area were included in this study. Thirty-one patients underwent open rhinoplasty with the sill approach from the lower third of the columella, while 23 patients underwent rhinoplasty with a nostril base approach for nasal sill augmentation procedure. There were no reports of patient dissatisfaction, infection, bleeding, sensory dysfunction, or remaining asymmetry of the sill area.

Conclusion

Based on the findings of the present study, this technique can be successfully used in reconstructing the nasal sill area with minimal complications and morbidity.
Application of Machine Learning in Translational Medicine: Current Status and Future Opportunities
Authors: Terranova Nadia , Venkatakrishnan Karthik , Benincosa Lisa J.
Published: May 2021

The exponential increase in our ability to harness multi-dimensional biological and clinical data from experimental to real-world settings has transformed pharmaceutical research and development in recent years, with increasing applications of artificial intelligence (AI) and machine learning (ML). Patient-centered iterative forward and reverse translation is at the heart of precision medicine discovery and development across the continuum from target validation to optimization of pharmacotherapy. Integration of advanced analytics into the practice of Translational Medicine is now a fundamental enabler to fully exploit information contained in diverse sources of big data sets such as “omics” data, as illustrated by deep characterizations of the genome, transcriptome, proteome, metabolome, microbiome, and exposome. In this commentary, we provide an overview of ML applications in drug discovery and development, aligned with the three strategic pillars of Translational Medicine (target, patient, dose) and offer perspectives on their potential to transform the science and practice of the discipline. Opportunities for integrating ML approaches into the discipline of Pharmacometrics are discussed and will revolutionize the practice of model-informed drug discovery and development. Finally, we posit that joint efforts of Clinical Pharmacology, Bioinformatics, and Biomarker Technology experts are vital in cross-functional team settings to realize the promise of AI/ML-enabled Translational and Precision Medicine.
Associations of Osteocalcin Forms With Metabolic Syndrome and Its Individual Components in Older Men: The Health In Men Study
Authors: Liu Xiaoying , Yeap Bu B , Brock Kaye E , Levinger Itamar , Golledge Jonathan , Flicker Leon , Brennan-Speranza Tara C
Published: May 2021

Context

The osteoblast-derived polypeptide, osteocalcin (OC), has been associated with lower risk of type 2 diabetes and metabolic syndrome (MetS) in several epidemiological studies. Animal studies have indicated the undercarboxylated form of OC (ucOC) drives its association with metabolic outcomes.

Objective

We compared associations of ucOC and carboxylated OC (cOC) with MetS and its components in older men.

Methods

A cross-sectional analysis of 2575 men aged ≥70 years and older resident in Perth, Western Australia. ucOC was assayed using a hydroxyapatite-binding method, and cOC calculated by subtracting ucOC from total OC. Main outcome measures were MetS and its components.

Results

Both lower serum ucOC and cOC levels, and the proportion of cOC (%cOC) were associated with less favorable metabolic parameters (higher waist circumference, triglyceride, glucose, blood pressure, and lower high-density lipoprotein cholesterol), whereas inverse associations were found with %ucOC. Men in the lowest quintile of ucOC had higher risk of MetS compared to men in the highest quintile (Q1 ≤ 7.7 vs Q5 > 13.8 ng/mL; OR = 2.4; 95% CI, 1.8-3.2). Men in the lowest quintile of cOC had higher risk of MetS compared to those in the highest quintile (≤ 5.8 vs > 13.0 ng/mL; OR = 2.4; 95% CI, 1.8-3.2).

Conclusion

Lower concentrations of serum ucOC or cOC were associated with less favorable metabolic parameters and a higher risk of MetS. In contrast, a lower proportion of ucOC was associated with better metabolic parameters and lower MetS risk. Further research is warranted to determine whether ucOC and cOC are suitable biomarkers for cardiometabolic risk in men.
The Rallying Call to Decolonize
Authors: Kerman Monique
Published: May 2021

When Okwui Enwezor gained world renown as artistic director of Documenta11 in 2002, his accomplishments as curator of contemporary African art were already well established. His In/Sight: African Photographers, 1940–Present, exhibition (1996) had the temerity to describe the intentional ways in which Africans shaped their own photographic representation in a medium whose history was as long and distinguished in Africa as in Europe. Enwezor’s 2001 exhibition The Short Century: Independence and Liberation Movements in Africa, 1945–1994, was a revelatory journey through the long process of colonial resistance and independence no less revolutionary for its astonishing range of content far beyond that of art objects, including film, music, theater, literature, and literature. In helming Documenta11, Enwezor not only included a historic number of non-white, non-European artists but also redefined the exhibition, before its opening in Kassel, by conceiving it as a final installment of several “platforms” staged worldwide. His were strategic, paradigmatic interventions engineered to globalize the art world, and they effectively amounted to acts of art-historical decolonization. Enwezor’s legacy is instructive. Achieving an inclusive and equitable art history that is sustainable requires decentralizing white, Eurocentric, male, cisgender, and heterosexual hegemony. In two of his final projects, large-scale solo shows of Frank Bowling and El Anatsui, exhibiting these artists on their own terms did just that. It is through his curatorial practice of art-world decolonization that Enwezor has issued a rallying cry. He has shown us the way forward.
Enwezor’s Model and Copenhagen’s Center for Art on Migration Politics
Authors: Nielsen Sabine Dahl , Petersen Anne Ring
Published: May 2021

One of the most remarkable signs of the importance and adaptability of Okwui Enwezor’s work is the way in which the transformative models for exhibition making that he developed have found their way into small-scale institutional spaces and extra-institutional contexts. Resourceful curators across the world have successfully translated his models into critical formats and inventive ways of producing social and political knowledge, carefully adjusted to local contexts and needs. The aim of this article is to trace the influential postcolonial “platforms model” that Enwezor conceptualized for Documenta11 to a small but internationally acclaimed gallery in Copenhagen: the Center for Art on Migration Politics (CAMP). The article falls into three parts. The first part introduces CAMP and the Danish context for migration, before the authors discuss core elements of Enwezor’s exemplary transformation of curating into the creation of platforms for political interventions at his Documenta11 exhibition. The second part seeks to answer three questions: What was the curatorial strategy and multisited structure that Enwezor and his team developed? How did their decolonizing approach help create inclusive, discursive, and curatorial spaces that contested the binaristic perception of the West as the center and the non-West as periphery and offer a vision of the (art) world as profoundly entangled and plurivocal? How has the organization of Documenta11 as a globally distributed network of discursively and conceptually interconnected platforms contributed to restructuring the exhibition venue and to rethinking the interrelationship between the exhibition, as it is traditionally understood as the very core of an art event, and exhibition-related events perceived as collateral, sometimes even dispensable, activities? The third part of the article returns to CAMP to explore the specific translation of Enwezor’s legacy into a small-scale, local art space.
Ethnic Envy and Other Aggressions in the Contemporary “Global” Art Complex
Authors: Jones Amelia
Published: May 2021

This article looks at Okui Enwezor’s theory of countering the art world’s “Westernisms” and his actualization of this theory in his organization of Documenta11 to mount an argument against the universalizing and Eurocentric conception of “global” art. It offers two examples of recent hybrid art/curatorial work in Los Angeles—the 2019 David Hammons show at Hauser and Wirth and the Crenshaw Dairy Mart’s arts activism—to argue for an extension of Enwezor’s model via activist and aesthetic interventions into specific sites and art spaces.
Rab11 is required for lysosome exocytosis through the interaction with Rab3a, Sec15 and GRAB
Authors: Escrevente Cristina , Bento-Lopes Liliana , Ramalho José S. , Barral Duarte C.
Published: May 2021

Lysosomes are dynamic organelles, capable of undergoing exocytosis. This process is crucial for several cellular functions, namely plasma membrane repair. Nevertheless, the molecular machinery involved in this process is poorly understood. Here, we identify Rab11a and Rab11b as regulators of Ca2+-induced lysosome exocytosis. Interestingly, Rab11-positive vesicles transiently interact with lysosomes at the cell periphery, indicating that this interaction is required for the last steps of lysosome exocytosis. Additionally, we found that the silencing of the exocyst subunit Sec15, a Rab11 effector, impairs lysosome exocytosis, suggesting that Sec15 acts together with Rab11 in the regulation of lysosome exocytosis. Furthermore, we show that Rab11 binds the guanine nucleotide exchange factor for Rab3a (GRAB) as well as Rab3a, which we have previously described to be a regulator of the positioning and exocytosis of lysosomes. Thus, our study identifies new players required for lysosome exocytosis and suggest the existence of a Rab11–Rab3a cascade involved in this process.
Genome-wide imaging screen uncovers molecular determinants of arsenite-induced protein aggregation and toxicity
Authors: Andersson Stefanie , Romero Antonia , Rodrigues Joana Isabel , Hua Sansan , Hao Xinxin , Jacobson Therese , Karl Vivien , Becker Nathalie , Ashouri Arghavan , Rauch Sebastien , Nyström Thomas , Liu Beidong , Tamás Markus J.
Published: May 2021

The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis.

This article has an associated First Person interview with the first authors of the paper.
Amyloid-β oligomers block lysosomal targeting of miRNPs to prevent miRNP recycling and target repression in glial cells
Authors: De Dipayan , Bhattacharyya Suvendra N.
Published: May 2021

Upon exposure to amyloid-β oligomers (Aβ1–42), glial cells start expressing proinflammatory cytokines, despite an increase in levels of repressive microRNAs (miRNAs). Exploring the mechanism of this potential immunity of target cytokine mRNAs against repressive miRNAs in amyloid-β-exposed glial cells, we have identified differential compartmentalization of repressive miRNAs in glial cells that explains this aberrant miRNA function. In Aβ1–42-treated cells, whereas target mRNAs were found to be associated with polysomes attached to endoplasmic reticulum (ER), the miRNA ribonucleoprotein complexes (miRNPs) were found to be present predominantly with endosomes that failed to recycle to ER-attached polysomes, preventing repression of mRNA targets. Aβ1–42 oligomers, by masking Rab7a proteins on endosomal surfaces, affected Rab7a interaction with Rab-interacting lysosomal protein (RILP), restricting the lysosomal targeting and recycling of miRNPs. RNA-processing body (P-body) localization of the miRNPs was found to be enhanced in amyloid-β-treated cells as a consequence of enhanced endosomal retention of miRNPs. Interestingly, depletion of P-body components partly rescued the miRNA function in glial cells exposed to amyloid-β and restricted the excess cytokine expression.

This article has an associated First Person interview with the first author of the paper.
Metal pollutants have additive negative effects on honey bee cognition
Authors: Monchanin Coline , Drujont Erwann , Devaud Jean-Marc , Lihoreau Mathieu , Barron Andrew B.
Published: May 2021

Environmental pollutants can exert sublethal deleterious effects on animals. These include disruption of cognitive functions underlying crucial behaviours. While agrochemicals have been identified as a major threat to pollinators, metal pollutants, which are often found in complex mixtures, have so far been overlooked. Here, we assessed the impact of acute exposure to field-realistic concentrations of three common metal pollutants, lead, copper and arsenic, and their combinations, on honey bee appetitive learning and memory. All treatments involving single metals slowed down learning and disrupted memory retrieval at 24 h. Combinations of these metals had additive negative effects on both processes, suggesting common pathways of toxicity. Our results highlight the need to further assess the risks of metal pollution on invertebrates.
STUDY OF THE SCIENTIFIC THINKING STYLE OF TEACHERS
Authors: NIKOLOV NIKITA
Published: May 2021

THE SCIENTIFIC APPROBATION OF THE RESEARCH OF THE PECULIARITIES OF THE DEVELOPMENT OF THE SCIENTIFIC STYLE OF THINKING OF YOUNG TEACHERS OF ADDITIONAL PROFESSIONAL EDUCATION INSTITUTIONS IS PRESENTED. THE DEVELOPED PRODUCT ALLOWS TO OBTAIN OBJECTIVE DATA ON THE PECULIARITIES OF PROFESSIONAL AND PERSONAL GROWTH OF MODERN PEDAGOGICAL WORKERS. THE DEVELOPED FEEDBACK SYSTEM ALLOWS TO USE ADDRESSED EDUCATIONAL CONSULTING IMPROVING THE MONITORING SYSTEM OF SUCH NEW FORMATION AS A SCIENTIFIC STYLE OF THINKING.
Element Imbalance among Workers during Solar CellProduction
Authors: Kasatkina E. , Kontrosh Lidiya , Hramov A. , Shumilov O.
Published: May 2021

The solar cell production requires additional methods for workers protection, as well as certain conditions and requirements for the premises to meet them. Solar cell factories are equipped with clean rooms, which meet high environmental and worker protection requirements. Research laboratories often do not meet such protection conditions. Therefore, most often the working conditions in such laboratories are insufficient. In two research laboratories was conducted a study for the elemental composition of hair of workers engaged in the solar cell production and the production methods improvement. As a result of the study it was found an increased content of rare and rare earth metals in some workers’ body and hair. This study allows assess the level of production processes impact on the worker in the studied activity area.
Strategy for the Management of Pulp and Paper Industry’sWaste Containing Lignosulfonates
Authors: Glushankova I. , Zhulanova Alena , Arduanova A. , Mikov A.
Published: May 2021

The pulp and paper industry’s multi-tonnage liquid waste is spent cooking liquor containing lignosulfonates, which disposal and processing remains one of the most complex environmental and technological problems, which should be solved. Lignosulfonates have unique colloidal-chemical properties, which determines their high resource potential. However, lignosulfonates’ composition instability often does not provide the properties and indicators set by the consumer. Changing market conditions require constant waste monitoring and modification, that prevents the widespread lignosulfonates use in industrial practice. In this paper, the causes for the formation of lignin-containing waste and its impact on the environment are considered. A strategy for lignosulfonates utilization has been developed, as well as promising methods for these wastes processing and disposal, which will expand the use of lignosulfonates and reduce the pulp and paper industry negative impact on the environment.
Sangallo, Vignola, Palladio and the Roman «Accademia de lo Studio de l’Architettura».
Authors: Kulawik Bernd
Published: May 2021

Bernd Kulawik is a trained marine engineer who studied physics, musicology and philosophy at the Technical Universities of Dresden and Berlin. MA thesis in 1996 about Monteverdi’s «Seconda Pratica». PhD in 2002 with a dissertation about drawings in the Berlin «Codex Destailleur D» for Antonio da Sangallo the Younger’s last project for St. Peter’s in Rome. Since 1988 he worked in research libraries and institutes in Berlin, Rome, Berne, Einsiedeln and Zurich, mostly as developer for database projects. Since 2013 he could take up his research about the study of ancient architecture in Renaissance Rome which led to the rediscovery of the forgotten «Accademia de lo Studio de l’Architettura». This academy almost completely realised Claudio Tolomei’s ambitious program from 1542 formerly believed to be unrealisable. Other research interests are the history of philosophy, Renaissance music and the epistemic and technical preconditions as well as long-time perspectives of the Digital Humanities.
Use of upper-limb compression garments in lipoedema
Authors: Elwell Rebecca , Rich Anna
Published: May 2021

Compression hosiery is commonly used for the management of lymphoedema as well as lipoedema, but it is more commonly indicated for the lower limbs than for the upper limbs
Legal compliance with the new IR35 payroll rules
Authors: Paulin Michael
Published: May 2021

The ‘nightmare legislation’ of IR35 is going to affect GP surgeries – so what do primary care practice managers need to know to protect themselves? Michael Paulin explains
Applying the science of behaviour change to the management of strangles
Authors: White Jo , Prescott Kayna , Rogers Suzanne
Published: May 2021

The Strangles Symposium in 2019 gathered equine stakeholders from across the industry to discuss the management and prevention of strangles in the UK. The understanding of Streptococcus equi is increasing as is the ability to identify and treat the disease. There is real potential to reduce the incidence of the disease, as highlighted through the guidance produced by experts in 2021. It has been recognised that the preventative measures identified require the behaviour of people across the equine industry to alter. The science of human behaviour change can support the veterinary profession in applying effective, evidence-based interventions to optimise the success of these changes. Pinpointing what behaviours are or are not being performed, and researching what is motivating these behaviours, is key to forming strategies within veterinary practice and at UK policy level, to ensure a targeted and consistent approach is available for people within the equine sector.
Optimising the welfare of equids on box rest: thinking outside the box
Authors: Prescott Kayna
Published: May 2021

Restriction of equids to a stable for box rest is advisable for the management of acute physiological conditions. Confinement to a single stable is not an optimal environment for a horse and can create frustration and the expression of abnormal behaviours, which can indicate a reduced welfare state. Expression of aggression towards handlers or rebound behaviours when released from the stable can be a safety concern for handlers and gives the potential for reinjury. By reviewing the literature, we can consider what aspects of the environment can be adjusted to allow optimal expression of natural behaviour within the stable, subsequently reducing frustration and stress which will improve the welfare of the equine on box rest and potentially improve the safety of handlers.
Equine behavioural first aid and combatting stress in equines
Authors: Nellist Jennifer M
Published: May 2021

Behavioural first aid is for the prevention of harm to equids and humans. The need for behavioural first aid is either immediately apparent on examination or requested by a client because of the occurrence of undesirable and/or dangerous behaviour. Delivering effective first aid advice relies on recognising the problem, providing immediate, practical interim solutions, or referral to an appropriate behavioural practitioner. Behaviour itself is related to the equine's social and environmental situation, its emotional experience and the behavioural goal. Challenging behaviour is often related to lack of predictability or control in the equine's life, caused by sub-optimal management or during exposure to painful, frightening or confusing equitation practices that do not adhere to the principles of learning theory. The goal of behavioural first aid is to preserve the safety and welfare of the equine and their human connections until the animal is referred on. As such, being able to undertake behavioural first aid should be considered a valuable skill and an asset to modern equine veterinary practice.
Morbidity and mortality in patients undergoing lower limb arthroplasty surgery during the initial surge of the COVID-19 pandemic in the UK at a single-speciality orthopaedic hospital
Authors: Agrawal Yuvraj , Vasudev Ashish , Sharma Akash , Cooper George , Stevenson Jonathan , Parry Michael C. , Dunlop David
Published: May 2021

Aims

The COVID-19 pandemic posed significant challenges to healthcare systems across the globe in 2020. There were concerns surrounding early reports of increased mortality among patients undergoing emergency or non-urgent surgery. We report the morbidity and mortality in patients who underwent arthroplasty procedures during the UK first stage of the pandemic.

Methods

Institutional review board approval was obtained for a review of prospectively collected data on consecutive patients who underwent arthroplasty procedures between March and May 2020 at a specialist orthopaedic centre in the UK. Data included diagnoses, comorbidities, BMI, American Society of Anesthesiologists grade, length of stay, and complications. The primary outcome was 30-day mortality and secondary outcomes were prevalence of SARS-CoV-2 infection, medical and surgical complications, and readmission within 30 days of discharge. The data collated were compared with series from the preceding three months.

Results

There were 167 elective procedures performed in the first three weeks of the study period, prior to the first national lockdown, and 57 emergency procedures thereafter. Three patients (1.3%) were readmitted within 30 days of discharge. There was one death (0.45%) due to SARS-CoV-2 infection after an emergency procedure. None of the patients developed complications of SARS-CoV-2 infection after elective arthroplasty. There was no observed spike in complications during in-hospital stay or in the early postoperative period. There was no statistically significant difference in survival between pre-COVID-19 and peri-COVID-19 groups (p = 0.624). We observed a higher number of emergency procedures performed during the pandemic within our institute.

Conclusion

An international cohort has reported 30-day mortality as 28.8% following orthopaedic procedures during the pandemic. There are currently no reports on clinical outcomes of patients treated with lower limb reconstructive surgery during the same period. While an effective vaccine is developed and widely accepted, it is very likely that SARS-CoV2 infection remains endemic. We believe that this report will help guide future restoration planning here in the UK and abroad. Cite this article: Bone Jt Open 2021;2(5):323–329.
Rotational speed measurement using self-mixing interferometry
Authors: Liu Yang , Liu Jigou , Kennel Ralph
Published: May 2021

Self-mixing interferometry (SMI) is a technique that is capable of measuring rotational speed in a direct way. Thus, SMI is an attractive alternative to optical encoders with respect to speed detection. But problems such as additive noises as well as amplitude and frequency modulation due to spectral broadening make the usage of self-mixing interferometry challenging. In this paper, a signal processing method with relative high accuracy is presented for rotational speed measurement using SMI. The method uses of signal selection, autocorrelation, zero-crossing detection, as well as an averaging filter to determine the Doppler frequency of a SMI signal more accurately. Results of experiments show the method’s potential, as the linearity of the measuring system is

≤

±

0.5

%

and the normalized root mean square error is

≤

0.2

%

.
Atmospheric turbulence characterization through multiframe blind deconvolution
Authors: Webb Adam J. , Roggemann Michael C. , Whiteley Matthew R.
Published: May 2021

Characterization of turbulence in the atmosphere and mitigation of its
effects in optical systems are important capabilities in both
commercial and military applications. We present an image processing
approach that jointly characterizes the magnitude of turbulence in the
atmosphere and mitigates the adverse effects imposed on optical
imaging systems. The magnitude of turbulence is measured indirectly
through a series of image frames in terms of the atmospheric coherence
length. We believe the results demonstrate the utility of the approach
on both simulated and experimental data.
Design and analysis of a compact subwavelength-grating-assisted 1.55/2  µm wavelength demultiplexer
Authors: Liao Jianfei , Xie Yuan , Huang Tianye , Cheng Zhuo
Published: May 2021

The wavelength demultiplexer (deWMUX) is an indispensable component for the wavelength diversity system. In this paper, we propose a subwavelength-grating-assisted

1

×

2

deWMUX based on the principle of multimode interference, which aims to output 1.55 and 2 µm wavelengths from two different channels. The simulation results show that the contrast of the designed deWMUX at both wavelengths is greater than 24 dB, the insertion loss is less than 0.5 dB, and the 1 dB bandwidth is wider than 100 nm. In addition, the manufacturing tolerances of the device are also studied.
High resolution optical projection tomography platform for multispectral imaging of the mouse gut
Authors: Schmidt Cédric , Planchette Arielle L. , Nguyen David , Giardina Gabriel , Neuenschwander Yoan , Franco Mathieu Di , Mylonas Alessio , Descloux Adrien C. , Pomarico Enrico , Radenovic Aleksandra , Extermann Jérôme
Published: May 2021

Optical projection tomography (OPT) is a powerful tool for three-dimensional
imaging of mesoscopic biological samples with great use for biomedical
phenotyping studies. We present a fluorescent OPT platform that enables direct
visualization of biological specimens and processes at a centimeter scale with
high spatial resolution, as well as fast data throughput and reconstruction. We
demonstrate nearly isotropic sub-28 µm resolution over more than 60
mm3 after reconstruction of a single acquisition. Our setup is
optimized for imaging the mouse gut at multiple wavelengths. Thanks to a new
sample preparation protocol specifically developed for gut specimens, we can
observe the spatial arrangement of the intestinal villi and the vasculature
network of a 3-cm long healthy mouse gut. Besides the blood vessel network
surrounding the gastrointestinal tract, we observe traces of vasculature at the
villi ends close to the lumen. The combination of rapid acquisition and a large
field of view with high spatial resolution in 3D mesoscopic imaging holds an
invaluable potential for gastrointestinal pathology research.
Label-free photoacoustic microscopy: a potential tool for the live imaging of blood disorders in zebrafish
Authors: Yang Wenzhao , Wang Wei , Jing Lili , Chen Sung-Liang
Published: May 2021

The zebrafish has emerged as a useful model for human hematological disorders. Transgenic zebrafish that express green fluorescence protein (GFP) in red blood cells (RBCs) visualized by fluorescence microscopy (FLM) is a fundamental approach in such studies to understand the cellular processes and biological functions. However, additional and cumbersome efforts are required to breed a transgenic zebrafish line with reliable GFP expression. Further, the yolk autofluorescence and finite GFP fluorescence lifetimes also have an adverse impact on the observation of target signals. Here, we investigate the identification of intracerebral hemorrhage (ICH) and hemolytic anemia (HA) in zebrafish embryos using label-free photoacoustic microscopy (PAM) for imaging. First, ICH and HA in transgenic LCR-EGFP zebrafish are mainly studied by PAM and FLM. The results show that PAM is comparable to FLM in good identification of ICH and HA. Besides, PAM is more advantageous in circumventing the issue of autofluorescence. Secondly, ICH and HA in the transparent casper zebrafish without fluorescent labeling are imaged by PAM and bright-field microscopy (BFM). Because of the high contrast to reveal RBCs, PAM obviously outperforms BFM in the identification of both ICH and HA. Note that FLM cannot observe casper zebrafish due to its lack of fluorescent labeling. Our work proves that PAM can be a useful tool to study blood disorders in zebrafish, which has advantages: (i) Reliable results enabled by intrinsic absorption of RBCs; (ii) wide applicability to zebrafish strains (no requirement of a transgene); (iii) high sensitivity in identification of ICH and HA compared with BFM.
Choosing a model for laser speckle contrast imaging
Authors: Liu Chang , Kılıç Kıvılcım , Erdener Sefik Evren , Boas David A. , Postnov Dmitry D.
Published: May 2021

Laser speckle contrast imaging (LSCI) is a real-time full-field non-invasive technique, which is broadly applied to visualize blood flow in biomedical applications. In its foundation is the link between the speckle contrast and dynamics of light scattering particles–erythrocytes. The mathematical form describing this relationship, which is critical for accurate blood flow estimation, depends on the sample’s light-scattering properties. However, in biological applications, these properties are often unknown, thus requiring assumptions to be made to perform LSCI analysis. Here, we review the most critical assumptions in the LSCI theory and simulate how they affect blood flow estimation accuracy. We show that the most commonly applied model can severely underestimate the flow change, particularly when imaging brain parenchyma or other capillary perfused tissue (e.g. skin) under ischemic conditions. Based on these observations and guided by the recent experimental results, we propose an alternative model that allows measuring blood flow changes with higher accuracy.
Instability of optical phase synchronization between chaotic semiconductor lasers
Authors: Mao Xiaoxin , Sun Yuchuan , Wang Longsheng , Guo Yuanyuan , Gao Zhensen , Wang Yuncai , Li Songsui , Yan Lianshan , Wang Anbang
Published: May 2021

The instability of optical phase chaos synchronization between semiconductor lasers under master–slave open-loop configuration is investigated. The phase difference between the master and slave lasers is obtained and analyzed in experiment by heterodyne detection and Hilbert transform, and in simulation by solving the rate equations. The results show that the phase difference only maintains in a short duration time and then jumps to another value. A statistical analysis shows that both duration time and jumping values are random, proving that the phase chaos synchronization is unstable. A theoretical analysis shows that the instability of phase synchronization is caused by the jumping of the external cavity mode in the master laser.
Design of a Littrow-type diode laser with independent control of cavity length and grating rotation
Authors: Duca Lucia , Perego Elia , Berto Federico , Sias Carlo
Published: May 2021

We present a novel, to the best of our knowledge, extended-cavity diode laser based on a modified Littrow configuration. The coarse wavelength adjustment via the rotation of a diffraction grating is decoupled from the fine tuning of the external cavity modes by positioning a piezo transducer behind the diode laser, making the laser robust against misalignment and hysteresis even with long external cavities. Two laser prototypes with external cavities of different lengths were tested with a 780 nm laser diode, and locked to an atomic reference. We observed a mode-hop-free frequency tunability broader than the free spectral range of the external cavity upon changes in its length. The design is well suited to atomic and molecular experiments demanding a high level of stability over time.
Birefringence and scattering characterization using polarization sensitive quantum optical coherence tomography
Authors: Sukharenko Vitaly , Bikorimana Simeon , Dorsinville Roger
Published: May 2021

Polarization sensitive quantum optical coherence tomography (PS-QOCT) is used to characterize birefringence, scattering/absorption and path length differences in a flat transparent plastic sample. In this Letter, we present the first, to the best of our knowledge, experimental technique of PS-QOCT imaging and characterization of a birefringent material. Polarization sensitive coincidence rate of the entangled photons measured for each pixel and the 2D cross-sectional images are reconstructed. The technique described in this work has many potential applications in the characterization of micro and nano structures, including biological samples.
Method to obtain the initial value for the inverse design in nanophotonics based on a time-reversal technique
Authors: Wang Zhipeng , Wang Bing-Zhong , Liu Jin-Pin , Wang Ren
Published: May 2021

In the inverse design of nanophotonic devices, mathematical optimization methods are generally used to perform local optimization in the design region to obtain the physical structure that meets design expectations. These methods usually produce good structures. However, due to the lack of physical considerations, most of the inverse design methods for nanophotonic devices use random initial topology as the initialization for optimization, which will inevitably cause a waste of computing resources. In this Letter, we propose a method based on a time-reversal technique to quickly determine the induced source of the physical structure in the design region and, thus, obtain the initial topological structure of the nanophotonic devices. For a nanophotonic 90°-bend waveguide and 90°-bend power splitter waveguide, numerical examples show that the initial topology obtained by our method not only has good initial performance, but also can be used as a reasonable initialization for inverse design.
Integrated transcriptomics and epigenomics reveal chamber-specific and species-specific characteristics of human and mouse hearts
Authors: Gao Junpeng , Zheng Yuxuan , Li Lin , Lu Minjie , Chen Xiangjian , Wang Yu , Li Yanna , Liu Xiaomeng , Gao Yun , Mao Yunuo , Zhao Peng , Zhang Jinan , Tang Fuchou , Song Lei , Wen Lu , Wang Jizheng
Published: May 2021

DNA methylation, chromatin accessibility, and gene expression represent different levels information in biological process, but a comprehensive multiomics analysis of the mammalian heart is lacking. Here, we applied nucleosome occupancy and methylome sequencing, which detected DNA methylation and chromatin accessibility simultaneously, as well as RNA-seq, for multiomics analysis of the 4 chambers of adult and fetal human hearts, and adult mouse hearts. Our results showed conserved region-specific patterns in the mammalian heart at transcriptome and DNA methylation level. Adult and fetal human hearts showed distinct features in DNA methylome, chromatin accessibility, and transcriptome. Novel long noncoding RNAs were identified in the human heart, and the gene expression profiles of major cardiovascular diseases associated genes were displayed. Furthermore, cross-species comparisons revealed human-specific and mouse-specific differentially expressed genes between the atria and ventricles. We also reported the relationship among multiomics and found there was a bell-shaped relationship between gene-body methylation and expression in the human heart. In general, our study provided comprehensive spatiotemporal and evolutionary insights into the regulation of gene expression in the heart.
scHiCTools: A computational toolbox for analyzing single-cell Hi-C data
Authors: Li Xinjun , Feng Fan , Pu Hongxi , Leung Wai Yan , Liu Jie
Published: May 2021

Single-cell Hi-C (scHi-C) sequencing technologies allow us to investigate three-dimensional chromatin organization at the single-cell level. However, we still need computational tools to deal with the sparsity of the contact maps from single cells and embed single cells in a lower-dimensional Euclidean space. This embedding helps us understand relationships between the cells in different dimensions, such as cell-cycle dynamics and cell differentiation. We present an open-source computational toolbox, scHiCTools, for analyzing single-cell Hi-C data comprehensively and efficiently. The toolbox provides two methods for screening single cells, three common methods for smoothing scHi-C data, three efficient methods for calculating the pairwise similarity of cells, three methods for embedding single cells, three methods for clustering cells, and a build-in function to visualize the cells embedding in a two-dimensional or three-dimensional plot. scHiCTools, written in Python3, is compatible with different platforms, including Linux, macOS, and Windows.
Robust switches in thalamic network activity require a timescale separation between sodium and T-type calcium channel activations
Authors: Jacquerie Kathleen , Drion Guillaume
Published: May 2021

Switches in brain states, synaptic plasticity and neuromodulation are fundamental processes in our brain that take place concomitantly across several spatial and timescales. All these processes target neuron intrinsic properties and connectivity to achieve specific physiological goals, raising the question of how they can operate without interfering with each other. Here, we highlight the central importance of a timescale separation in the activation of sodium and T-type calcium channels to sustain robust switches in brain states in thalamic neurons that are compatible with synaptic plasticity and neuromodulation. We quantify the role of this timescale separation by comparing the robustness of rhythms of six published conductance-based models at the cellular, circuit and network levels. We show that robust rhythm generation requires a T-type calcium channel activation whose kinetics are situated between sodium channel activation and T-type calcium channel inactivation in all models despite their quantitative differences.
Real-time single-cell characterization of the eukaryotic transcription cycle reveals correlations between RNA initiation, elongation, and cleavage
Authors: Liu Jonathan , Hansen Donald , Eck Elizabeth , Kim Yang Joon , Turner Meghan , Alamos Simon , Garcia Hernan G.
Published: May 2021

The eukaryotic transcription cycle consists of three main steps: initiation, elongation, and cleavage of the nascent RNA transcript. Although each of these steps can be regulated as well as coupled with each other, their in vivo dissection has remained challenging because available experimental readouts lack sufficient spatiotemporal resolution to separate the contributions from each of these steps. Here, we describe a novel application of Bayesian inference techniques to simultaneously infer the effective parameters of the transcription cycle in real time and at the single-cell level using a two-color MS2/PP7 reporter gene and the developing fruit fly embryo as a case study. Our method enables detailed investigations into cell-to-cell variability in transcription-cycle parameters as well as single-cell correlations between these parameters. These measurements, combined with theoretical modeling, suggest a substantial variability in the elongation rate of individual RNA polymerase molecules. We further illustrate the power of this technique by uncovering a novel mechanistic connection between RNA polymerase density and nascent RNA cleavage efficiency. Thus, our approach makes it possible to shed light on the regulatory mechanisms in play during each step of the transcription cycle in individual, living cells at high spatiotemporal resolution.
Distinguishing African bovids using Zooarchaeology by Mass Spectrometry (ZooMS): New peptide markers and insights into Iron Age economies in Zambia
Authors: Janzen Anneke , Richter Kristine Korzow , Mwebi Ogeto , Brown Samantha , Onduso Veronicah , Gatwiri Filia , Ndiema Emmanuel , Katongo Maggie , Goldstein Steven T. , Douka Katerina , Boivin Nicole
Published: May 2021

Assessing past foodways, subsistence strategies, and environments depends on the accurate identification of animals in the archaeological record. The high rates of fragmentation and often poor preservation of animal bones at many archaeological sites across sub-Saharan Africa have rendered archaeofaunal specimens unidentifiable beyond broad categories, such as “large mammal” or “medium bovid”. Identification of archaeofaunal specimens through Zooarchaeology by Mass Spectrometry (ZooMS), or peptide mass fingerprinting of bone collagen, offers an avenue for identification of morphologically ambiguous or unidentifiable bone fragments from such assemblages. However, application of ZooMS analysis has been hindered by a lack of complete reference peptide markers for African taxa, particularly bovids. Here we present the complete set of confirmed ZooMS peptide markers for members of all African bovid tribes. We also identify two novel peptide markers that can be used to further distinguish between bovid groups. We demonstrate that nearly all African bovid subfamilies are distinguishable using ZooMS methods, and some differences exist between tribes or sub-tribes, as is the case for Bovina (cattle) vs. Bubalina (African buffalo) within the subfamily Bovinae. We use ZooMS analysis to identify specimens from extremely fragmented faunal assemblages from six Late Holocene archaeological sites in Zambia. ZooMS-based identifications reveal greater taxonomic richness than analyses based solely on morphology, and these new identifications illuminate Iron Age subsistence economies c. 2200–500 cal BP. While the Iron Age in Zambia is associated with the transition from hunting and foraging to the development of farming and herding, our results demonstrate the continued reliance on wild bovids among Iron Age communities in central and southwestern Zambia Iron Age and herding focused primarily on cattle. We also outline further potential applications of ZooMS in African archaeology.
Assessment of the evolution of end-tidal carbon dioxide within chest compression pauses to detect restoration of spontaneous circulation
Authors: Gutiérrez Jose Julio , Leturiondo Mikel , Ruiz de Gauna Sofía , Ruiz Jesus María , Azcarate Izaskun , González-Otero Digna María , Urtusagasti Juan Francisco , Russell James Knox , Daya Mohamud Ramzan
Published: May 2021

Background

Measurement of end-tidal CO2 (ETCO2) can help to monitor circulation during cardiopulmonary resuscitation (CPR). However, early detection of restoration of spontaneous circulation (ROSC) during CPR using waveform capnography remains a challenge. The aim of the study was to investigate if the assessment of ETCO2 variation during chest compression pauses could allow for ROSC detection. We hypothesized that a decay in ETCO2 during a compression pause indicates no ROSC while a constant or increasing ETCO2 indicates ROSC.

Methods

We conducted a retrospective analysis of adult out-of-hospital cardiac arrest (OHCA) episodes treated by the advanced life support (ALS). Continuous chest compressions and ventilations were provided manually. Segments of capnography signal during pauses in chest compressions were selected, including at least three ventilations and with durations less than 20 s. Segments were classified as ROSC or non-ROSC according to case chart annotation and examination of the ECG and transthoracic impedance signals. The percentage variation of ETCO2 between consecutive ventilations was computed and its average value, ΔETavg, was used as a single feature to discriminate between ROSC and non-ROSC segments.

Results

A total of 384 segments (130 ROSC, 254 non-ROSC) from 205 OHCA patients (30.7% female, median age 66) were analyzed. Median (IQR) duration was 16.3 (12.9,18.1) s. ΔETavg was 0.0 (-0.7, 0.9)% for ROSC segments and -11.0 (-14.1, -8.0)% for non-ROSC segments (p < 0.0001). Best performance for ROSC detection yielded a sensitivity of 95.4% (95% CI: 90.1%, 98.1%) and a specificity of 94.9% (91.4%, 97.1%) for all ventilations in the segment. For the first 2 ventilations, duration was 7.7 (6.0, 10.2) s, and sensitivity and specificity were 90.0% (83.5%, 94.2%) and 89.4 (84.9%, 92.6%), respectively. Our method allowed for ROSC detection during the first compression pause in 95.4% of the patients.

Conclusion

Average percent variation of ETCO2 during pauses in chest compressions allowed for ROSC discrimination. This metric could help confirm ROSC during compression pauses in ALS settings.