bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring Predictors of Response to Dacomitinib in EGFR-Amplified Recurrent Glioblastoma
Authors: Chi Andrew S. , Cahill Daniel P. , Reardon David A. , Wen Patrick Y. , Mikkelsen Tom , Peereboom David M. , Wong Eric T. , Gerstner Elizabeth R. , Dietrich Jorg , Plotkin Scott R. , Norden Andrew D. , Lee Eudocia Q. , Nayak Lakshmi , Tanaka Shota , Wakimoto Hiroaki , Lelic Nina , Koerner Mara V. , Klofas Lindsay K. , Bertalan Mia S. , Arrillaga-Romany Isabel C. , Betensky Rebecca A. , Curry William T. , Borger Darrel R. , Balaj Leonora , Kitchen Robert R. , Chakrabortty Sudipto K. , Valentino Michael D. , Skog Johan , Breakefield Xandra O. , Iafrate A. John , Batchelor Tracy T.
Published: June 2020

PURPOSE

Despite the high frequency of EGFR genetic alterations in glioblastoma (GBM), EGFR-targeted therapies have not had success in this disease. To improve the likelihood of efficacy, we targeted adult patients with recurrent GBM enriched for EGFR gene amplification, which occurs in approximately half of GBM, with dacomitinib, a second-generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that penetrates the blood-brain barrier, in a multicenter phase II trial.

PATIENTS AND METHODS

We retrospectively explored whether previously described EGFR extracellular domain (ECD)–sensitizing mutations in the context of EGFR gene amplification could predict response to dacomitinib, and in a predefined subset of patients, we measured post-treatment intratumoral dacomitinib levels to verify tumor penetration.

RESULTS

We found that dacomitinib effectively penetrates contrast-enhancing GBM tumors. Among all 56 treated patients, 8 (14.3%) had a clinical benefit as defined by a duration of treatment of at least 6 months, of whom 5 (8.9%) remained progression free for at least 1 year. Presence of EGFRvIII or EGFR ECD missense mutation was not associated with clinical benefit. We evaluated the pretreatment transcriptome in circulating extracellular vesicles (EVs) by RNA sequencing in a subset of patients and identified a signature that distinguished patients who had durable benefit versus those with rapid progression.

CONCLUSION

While dacomitinib was not effective in most patients with EGFR-amplified GBM, a subset experienced a durable, clinically meaningful benefit. Moreover, EGFRvIII and EGFR ECD mutation status in archival tumors did not predict clinical benefit. RNA signatures in circulating EVs may warrant investigation as biomarkers of dacomitinib efficacy in GBM.
Treatment of Acromegalic Osteopathy in Real-life Clinical Practice: The BAAC (Bone Active Drugs in Acromegaly) Study
Authors: Mazziotti Gherardo , Battista Claudia , Maffezzoni Filippo , Chiloiro Sabrina , Ferrante Emanuele , Prencipe Nunzia , Grasso Ludovica , Gatto Federico , Olivetti Roberto , Arosio Maura , Barale Marco , Bianchi Antonio , Cellini Miriam , Chiodini Iacopo , De Marinis Laura , Del Sindaco Giulia , Di Somma Carolina , Ferlin Alberto , Ghigo Ezio , Giampietro Antonella , Grottoli Silvia , Lavezzi Elisabetta , Mantovani Giovanna , Morenghi Emanuela , Pivonello Rosario , Porcelli Teresa , Procopio Massimo , Pugliese Flavia , Scillitani Alfredo , Lania Andrea Gerardo
Published: June 2020

Background

Vertebral fractures (VFs) are a frequent complication of acromegaly, but no studies have been so far published on effectiveness of antiosteoporotic drugs in this clinical setting.

Objective

To evaluate whether in real-life clinical practice bone active drugs may reduce the risk of VFs in patients with active or controlled acromegaly.

Study design

Retrospective, longitudinal study including 9 tertiary care endocrine units.

Patients and Methods

Two hundred and forty-eight patients with acromegaly (104 males; mean age 56.00 ± 13.60 years) were evaluated for prevalent and incident VFs by quantitative morphometric approach. Bone active agents were used in 52 patients (20.97%) and the median period of follow-up was 48 months (range 12-132).

Results

During the follow-up, 65 patients (26.21%) developed incident VFs in relationship with pre-existing VFs (odds ratio [OR] 3.75; P < .001), duration of active acromegaly (OR 1.01; P = .04), active acromegaly at the study entry (OR 2.48; P = .007), and treated hypoadrenalism (OR 2.50; P = .005). In the entire population, treatment with bone active drugs did not have a significant effect on incident VFs (P = .82). However, in a sensitive analysis restricted to patients with active acromegaly at study entry (111 cases), treatment with bone active drugs was associated with a lower risk of incident VFs (OR 0.11; P = .004), independently of prevalent VFs (OR 7.65; P < .001) and treated hypoadrenalism (OR 3.86; P = .007).

Conclusions

Bone active drugs may prevent VFs in patients with active acromegaly.
From the Critique of Violence to the Critique of Rights
Authors: Lloyd David
Published: June 2020

This essay addresses Walter Benjamin's “Critique of Violence” to draw out the implications of the paradox he notes, that an exercise of a right, if it calls into question the legitimacy of the legal order, can be perceived by the state as violent, even where it is, strictly speaking, nonviolent. Benjamin theorized this in relation to the general strike, which reveals “an objective contradiction in the legal situation” that is nonetheless fundamental to the problematic constitution-in-violence of the state itself. His meditation on the strike can be extended to boycott, divestment, and sanctions as nonviolent exercises of a right that are understood by the state as destructive acts of violence: they present a challenge to the legitimacy of the state precisely in their will to abolish a condition of exclusion and differential rights that is constitutive of the state. In this respect, the observation that BDS seeks “the destruction of the state of Israel” finds its rationale and its limit within the logic of the “Critique of Violence” but also points beyond the institutions of rights, states, and law.
A heterodimeric SNX4­–SNX7 SNX-BAR autophagy complex coordinates ATG9A trafficking for efficient autophagosome assembly
Authors: Antón Zuriñe , Betin Virginie M. S. , Simonetti Boris , Traer Colin J. , Attar Naomi , Cullen Peter J. , Lane Jon D.
Published: June 2020

The sorting nexins (SNXs) are a family of peripheral membrane proteins that direct protein trafficking decisions within the endocytic network. Emerging evidence in yeast and mammalian cells implicates a subgroup of SNXs in selective and non-selective forms of autophagy. Using siRNA and CRISPR-Cas9, we demonstrate that the SNX-BAR protein SNX4 is needed for efficient LC3 (also known as MAP1LC3) lipidation and autophagosome assembly in mammalian cells. SNX-BARs exist as homo- and hetero-dimers, and we show that SNX4 forms functional heterodimers with either SNX7 or SNX30 that associate with tubulovesicular endocytic membranes. Detailed image-based analysis during the early stages of autophagosome assembly reveals that SNX4–SNX7 is an autophagy-specific SNX-BAR heterodimer, required for efficient recruitment and/or retention of core autophagy regulators at the nascent isolation membrane. SNX4 partially colocalises with juxtanuclear ATG9A-positive membranes, with our data linking the autophagy defect upon SNX4 disruption to the mis-trafficking and/or retention of ATG9A in the Golgi region. Taken together, our findings show that the SNX4–SNX7 heterodimer coordinates ATG9A trafficking within the endocytic network to establish productive autophagosome assembly sites, thus extending knowledge of SNXs as positive regulators of autophagy.
GDNF drives rapid tubule morphogenesis in a novel 3D in vitro model for ADPKD
Authors: Dixon Eryn E. , Maxim Demetrios S. , Halperin Kuhns Victoria L. , Lane-Harris Allison C. , Outeda Patricia , Ewald Andrew J. , Watnick Terry J. , Welling Paul A. , Woodward Owen M.
Published: June 2020

Cystogenesis is a morphological consequence of numerous genetic diseases of the epithelium. In the kidney, the pathogenic mechanisms underlying the program of altered cell and tubule morphology are obscured by secondary effects of cyst expansion. Here, we developed a new 3D tubuloid system to isolate the rapid changes in protein localization and gene expression that correlate with altered cell and tubule morphology during cyst initiation. Mouse renal tubule fragments were pulsed with a cell differentiation cocktail including glial-derived neurotrophic factor (GDNF) to yield collecting duct-like tubuloid structures with appropriate polarity, primary cilia, and gene expression. Using the 3D tubuloid model with an inducible Pkd2 knockout system allowed the tracking of morphological, protein, and genetic changes during cyst formation. Within hours of inactivation of Pkd2 and loss of polycystin-2, we observed significant progression in tubuloid to cyst morphology that correlated with 35 differentially expressed genes, many related to cell junctions, matrix interactions, and cell morphology previously implicated in cystogenesis.

This article has an associated First Person interview with the first author of the paper.
Ultrasound Use and Outpatient Management for Pyogenic Flexor Tenosynovitis: A Case Report
Authors: Schroeder Paul B. , Hutto Wesley M. , Leggit Jeffery C. , Parker Charles H.
Published: June 2020

Pyogenic flexor tenosynovitis (PFT) is an orthopedic emergency that necessitates prompt diagnosis and treatment. Unfortunately, the diagnosis is largely clinically based on Kanavel's four cardinal signs with all four symptoms being present approximately 22% to 56% of the time. Evidence suggests that PFT diagnosed within 48 h of onset does not need surgical intervention. Ultrasonography can be used to aid in the diagnosis of PFT. It has a sensitivity of 94.4% and a negative predictive value of 96.7%. This illustrative case report demonstrates ultrasound's utility to not only aid in diagnosis but also serve as a tool for monitoring patient response.
Utilization of Botulinum Toxin for Musculoskeletal Disorders
Authors: Moore Clint , Hulsopple Chad , Boyce Brett
Published: June 2020

Rehabilitation from musculoskeletal injuries is challenging with multiple intrinsic and extrinsic factors influencing athletes, conditions, and length of recovery. Multidisciplinary treatment strategies aim to address pathophysiology, mechanical, and psychosocial factors of injuries. An essential element in the recovery from musculoskeletal injuries is pain control and the return of physiologic function. There have been significant advancements in the understanding of pain and, therefore, new techniques and management strategies are being used. Botulinum neurotoxin (BoNT) has demonstrated valuable biopharmaceutical properties to provide neuromuscular blockade, which, in some cases, can help to return biomechanical and functional physiologic loss. There is developing literature in BoNT's ability to block pain in the treatment of painful musculoskeletal conditions. Critical analysis of the literature is necessary given the paucity of high-quality, evidence-based literature in the treatment of these conditions. This article reviews the utilization of BoNT in chronic exertional compartment syndrome, osteoarthritis, lateral epicondylosis, plantar fasciopathy, and myofascial pain syndrome.
Data extraction methods for systematic review (semi)automation: A living review protocol
Authors: Schmidt Lena , Olorisade Babatunde K. , McGuinness Luke A. , Thomas James , Higgins Julian P. T.
Published: June 2020

Background: Researchers in evidence-based medicine cannot keep up with the amounts of both old and newly published primary research articles. Support for the early stages of the systematic review process – searching and screening studies for eligibility – is necessary because it is currently impossible to search for relevant research with precision. Better automated data extraction may not only facilitate the stage of review traditionally labelled ‘data extraction’, but also change earlier phases of the review process by making it possible to identify relevant research. Exponential improvements in computational processing speed and data storage are fostering the development of data mining models and algorithms. This, in combination with quicker pathways to publication, led to a large landscape of tools and methods for data mining and extraction.

Objective: To review published methods and tools for data extraction to (semi)automate the systematic reviewing process.

Methods: We propose to conduct a living review. With this methodology we aim to do constant evidence surveillance, bi-monthly search updates, as well as review updates every 6 months if new evidence permits it. In a cross-sectional analysis we will extract methodological characteristics and assess the quality of reporting in our included papers.

Conclusions: We aim to increase transparency in the reporting and assessment of automation technologies to the benefit of data scientists, systematic reviewers and funders of health research. This living review will help to reduce duplicate efforts by data scientists who develop data mining methods. It will also serve to inform systematic reviewers about possibilities to support their data extraction.
Workplace exposure to carbon dioxide during routine laparoscopy – is it safe?
Authors: af Petersens Malin , Andersson Fenger-Krog Fritiof , Jakobsson Jan G.
Published: June 2020

Background: Minimally invasive surgeries have increased dramatically during the last decades. Carbon dioxide (CO2) is the gas used for insufflation during laparoscopies, creating space and visibility. The CO2 leaks into ambient air through ports where instruments are inserted. If the CO2 reaches a certain concentration it affects personnel health. There are national occupational exposure limits (OEL) for CO2, including a level limit value (LLV) of 5000 ppm. We are not aware of any previous studies addressing occupational exposure to CO2 during laparoscopies. The aim of this study was to assess the compliance to national OELs for CO2 during laparoscopies.

Methods: A gas detector was placed in the breathing zone of personnel in the operating theatre. The detector measured CO2 concentrations every tenth minute during laparoscopies in three locations.

Results: During 27 laparoscopies, the measured CO2 reached a maximum concentration of 1100 ppm, less than one fourth of the LLV. Median CO2 concentration was 700 ppm.

Conclusion: Results show that the occupational exposure to CO2 during laparoscopies is well below set OELs. Our findings support personnel safety associated with routine use of CO2 during laparoscopies.
Transport support trading activities
Authors: Kochinov Yuriy , Kochinova Tat'yana
Published: June 2020

The tutorial discusses the current state of the transport system of Russia, types and marking of goods, terms of delivery of goods characteristics of modes of transport; describes the types of cargo and performance evaluation of transport; the data for the practical solution of situational tasks and test questions for independent work and test knowledge.
Meets the requirements of Federal state educational standards of higher education of the last generation.
For undergraduate students enrolled in field of study "trading business" and other economic areas.
Dynamics of engines. Course design
Authors: Goc Aleksandr
Published: June 2020

Brief data from theory in the discipline "Theory of engines" and the order of execution of the course project. In a compact form the basic formulas and clarifications for the implementation of the relevant parts of the course project. As an example, the calculation-explanatory note and drawings done by a student course project review.
Meets the requirements of Federal state educational standards of higher education of the last generation.
Intended for students of day and correspondence forms of training areas of training 13.03.03 power mechanical engineering and 23.03.03 "Exploitation of transport and technological machines and complexes".
Astronomy
Authors: Blagin Anatoliy , Kotova Ol'ga
Published: June 2020

Summarize the introductory course of astronomy, given the latest scientific data about space. Each section provides examples of tasks and tasks for independent work of students. Are regarded as standard tasks and Olympiad so the tutorial can also serve as a guide for solving problems of high complexity.
Designed for students in secondary vocational education. It may be useful to the students of gymnasiums, secondary schools and Junior students of universities and teachers of natural science disciplines. Can also be used for self-education.
Mastering the Methods of Cognition of Natural Phenomena As an Important Component of the Natural Science Functional Literacy of a Primary Schoolchild
Authors: Timofeeva L.
Published: June 2020

The article discusses the features of building the process of familiarizing elementary schoolchildren with scientific methods of cognition

(observation, experience) and their application to obtain new knowledge, solve educational, practical and educational-cognitive problems. This direction of educational activity of schoolchildren implements meta-subject learning outcomes in accordance with the requirements of the Federal State Educational Standard of Primary General Education, and also forms the basis of natural-scientific functional literacy among younger schoolchildren. On the basis of the author’s study, the principles of adapting scientific methods of cognition for use as ways of organizing learning activities are determined; the main stages of the formation of the ability of students to use scientific methods of cognition in students are identified.
Economics of the nonprofit sector
Authors: Privalov Nikolay
Published: June 2020

The tutorial consists of five sections: "Subject matter and methodology of Economics of the nonprofit sector", "the Mechanism of reproduction of the product of the nonprofit sector", "Management in the nonprofit sector", "the Theory of the new society as a manifestation of the crisis of modern civilization", "the non-profit sector as a factor in maintaining the equilibrium of the social system". Each Chapter, in addition to theoretical material, lists of key concepts, test questions, assignments and test.
Meets the requirements of Federal state educational standards of higher education of the last generation.
Designed for students, postgraduates, professors, researchers and practitioners with specialties of Economics and management, including in the sphere of social communications and public relations.
Style and Skill: Hedge Funds, Mutual Funds, and Momentum
Authors: Grinblatt Mark , Jostova Gergana , Petrasek Lubomir , Philipov Alexander
Published: June 2020

Classifying mandatory 13F stockholding filings by manager type reveals that hedge fund strategies are mostly contrarian, and mutual fund strategies are largely trend following. The only institutional performers—the two thirds of hedge fund managers that are contrarian—earn alpha of 2.4% per year. Contrarian hedge fund managers tend to trade profitably with all other manager types, especially when purchasing stocks from momentum-oriented hedge and mutual fund managers. Superior contrarian hedge fund performance exhibits persistence and stems from stock-picking ability rather than liquidity provision. Aggregate short sales further support these conclusions about the style and skill of various fund manager types.

This paper was accepted by Tyler Shumway, finance.
The Impact of Social vs. Nonsocial Referring Channels on Online News Consumption
Authors: Bar-Gill Sagit , Inbar Yael , Reichman Shachar
Published: June 2020

The digitization of news markets has created a key role for online referring channels. This research combines field and laboratory experiments and analysis of large-scale clickstream data to study the effects of social versus nonsocial referral sources on news consumption in a referred news website visit. We theorize that referrer-specific browsing modes and referrer-induced news consumption thresholds interact to impact news consumption in referred visits to an online newspaper and that news sharing motivations invoked by the referral source impact sharing behavior in these referred visits. We find that social media referrals promote directed news consumption—visits with fewer articles, shorter durations, yet higher reading completion rates—compared with nonsocial referrals. Furthermore, social referrals invoke weaker informational sharing motivations relative to nonsocial referrals, thus leading to a lower news sharing propensity relative to nonsocial referrals. The results highlight how news consumption changes when an increasing amount of traffic is referred by social media, provide insights applicable to news outlets’ strategies, and speak to ongoing debates regarding biases arising from social media’s growing importance as an avenue for news consumption.

This paper was accepted by Anandhi Bharadwaj, information systems.
Advisor Beliefs, Practices, and Perceptions of Well-Being: Development of an Advisor Self-Evaluation Instrument
Authors: He Ye , Hutson Bryant L. , Bloom Jennifer L. , Cuevas Amanda Propst
Published: June 2020

Academic advising is integral to student success in higher education. However, few studies have explored the beliefs, practices, and well-being of advisors. In this study, we introduce an instrument designed to explore advisors' beliefs, practices, and well-being based on literature that addresses advising approaches and their theoretical connections, along with research on measuring well-being. Trends and themes of advisors' beliefs, practices, and factors associated with their perception of well-being were highlighted using responses from 136 advisors from various U.S. higher education institutions. We also consider implications from both individual and institutional perspectives.
Advising Adult Learners During the Transition to College
Authors: Karmelita Courtney
Published: June 2020

Adult learners represent a growing population of students in higher education who need various types of support to successfully embark on the transition to college. One popular type of support is a transition program, which aims to promote successful entrance to higher education. This study's findings imply that, while adult learners who have participated in transition programs continue to face challenges as they attempt to pursue higher education, the connections the participants made within transition programs helped mitigate the barriers they encountered. Additionally, the narratives of adult learners in this study demonstrate the need for academic advising during the transition to college. More research on the impact and effectiveness of transition programs is needed to develop programming that meets the needs of adult learners.
Early Declaration of a College Major and Its Relationship to Persistence
Authors: Spight David B.
Published: June 2020

As college completion rates are a top priority for institutions and other stakeholders, understanding college student persistence is important. Some perceive students making an early decision about a major as necessary for success in college, arguing that enrolling as undeclared contributes to student attrition. Previous research about undeclared students and persistence, however, is limited, conflicting, and dated. For this longitudinal study, logistic regression analyses were conducted using institutional records for 4,489 first-time in college, full-time enrolled students from the Fall 2010 cohort at a large research university in the Western United States. The results show no difference in persistence between students who matriculate as declared versus undeclared majors, which has implications for advising practice.
Rising to the challenges of COVID-19: the front line of care and support for people with long-term mental health problems and the response of Northern Healthcare
Authors: Winstanley Kelly , Tracey Noel , Mancey-Johnson Ashley , Gournay Kevin
Published: June 2020

The COVID-19 crisis has impacted on us all. However, people living with long-term mental health problems will remain vulnerable over the coming months, because of the restrictions that will remain in place until a vaccine has been discovered and used on the wider population. This paper describes how Northern Healthcare, an organisation that has developed a model of enhanced supported living for this population, has responded to the crisis. This response has seen a focus on residents, staff and on measures aimed at alleviating the burden on the wider NHS. Of importance, there are lessons to be learned, as it is entirely possible that the world will need to deal with future, similar pandemics.
Postoperative nausea and vomiting
Authors: Barnes Jonathan
Published: June 2020

Nausea and vomiting after surgery is common and can be both unpleasant and lead to an array of other adverse patient effects. Identification of high-risk patients and targeted prophylaxis can reduce its incidence and associated complications.
How the COVID-19 pandemic is affecting paediatric orthopaedics practice: A preliminary report
Authors: Peiro-Garcia Alejandro , Corominas Laura , Coelho Alexandre , DeSena-DeCabo Lidia , Torner-Rubies Ferran , Fontecha Cesar G.
Published: June 2020

Purpose

Since the state of alarm was decreed in Spain on 14 March 2020, the coronavirus disease 2019 (COVID-19) pandemic has had an extraordinary impact in paediatric hospitals. This study shows the effect of the pandemic on our practice in paediatric orthopaedics in a referral third level paediatric hospital.

Methods

We performed a single-centre retrospective review of the official census from a third level paediatric hospital from 14 March to 14 April for the years 2018, 2019 and 2020.

Results

The patients seen in our clinic during this period in 2020 decreased in by 82% (p < 0.001) compared with 2018 and 2019, however, the number of telemedicine consultations increased by 90.21% (p < 0.001). The total number of patients attending the clinic (including onsite and virtual) was reduced by 54.25% (p < 0.001). The total surgeries performed plummeted by 81% in this period in 2020 (p < 0.001) due to a reduction in elective cases of 94.6% (p < 0.001). No significant decrease was found in the number of urgent surgical cases per day in 2020 (p = 0.34). Finally, the number of orthopaedic patients admitted to our emergency department dropped by 78.6% during the state of alarm (p < 0.001).

Conclusion

According to our results, the pandemic has significantly affected our daily practice by decreasing elective surgeries and onsite clinics, but other activities have increased. As we have implemented telemedicine and new technologies to adapt to this setback, we should take advantage of the situation to change our practice in the future to better allocate our health resources and to anticipate outbreaks.

Published without peer review.

Level of Evidence

IV
Optical volumetric projection with large NA objectives for fast high-resolution 3D imaging of neural signals
Authors: Meng Qi , Xu Tianqi , Smith Zachary J. , Chu Kaiqin
Published: June 2020

One critical challenge in studying neural circuits of freely behaving model organisms is to record neural signals distributed within the whole brain, yet simultaneously maintaining cellular resolution. However, due to the dense packing of neuron cells in animal brains, high numerical aperture (NA) objectives are often required to differentiate neighboring neurons with the consequent need for axial scanning for whole brain imaging. Extending the depth of focus (EDoF) will be beneficial for fast 3D imaging of those neurons. However, current EDoF-enabled microscopes are primarily based on objectives with small NAs (≤0.3 ) such that the paraxial approximation can be applied. In this paper, we started from a nonparaxial approximation of the defocus aberration and derived a new phase mask that was appropriate for large NA microscopic systems. We validated the performance experimentally with a spatial light modulator (SLM) to create the designed phase mask. The performance was tested on different samples such as multilayered fluorescence beads and thick brain tissues, as well as with different objectives. Results confirmed that our design has extended the depth of focus about 10 fold and the image quality is much higher than those based on the most common EDoF method, the cubic phase method, popularly used to generate Airy beams. Meanwhile, our phase mask is rotationally symmetric and easy to fabricate. We fabricated one such phase plate and tested it on the pan-neuronal labeled Caenorhabditis elegans (C.elegans). The imaging performance demonstrated that we can capture all neurons in the whole brain with one snapshot and with cellular resolution, while the imaging speed is increased about 3 fold compared to the system using SLM. Thus we have shown that our method can not only provide the required imaging speed and resolution for studying neural activities in model animals, but also can be implemented as a low-cost, add-on module that can immediately augment existing fluorescence microscopes with only minor system modifications, and yielding substantially higher photon efficiency than SLM-based methods.
Extended depth of focus multiphoton microscopy via incoherent pulse splitting
Authors: Chen Bingying , Chakraborty Tonmoy , Daetwyler Stephan , Manton James D. , Dean Kevin , Fiolka Reto
Published: June 2020

We present a beam splitter mask that can be easily added to a
multiphoton raster scanning microscope to extend the depth of focus
five-fold at a small loss in lateral resolution. The method is
designed for ultrafast laser pulses or other light-sources featuring a
low coherence length. In contrast to other methods of focus extension,
our approach uniquely combines low complexity, high light-throughput
and multicolor capability. We characterize the point spread function
in a two-photon microscope and demonstrate fluorescence imaging of GFP
labeled neurons in fixed brain samples as imaged with conventional and
extended depth of focus two-photon microscopy.
Planar Airy beam light-sheet for two-photon microscopy
Authors: Hosny Neveen A. , Seyforth James A. , Spickermann Gunnar , Mitchell Thomas J. , Almada Pedro , Chesters Robert , Mitchell Scott J. , Chennell George , Vernon Anthony C. , Cho Kwangwook , Srivastava Deepak P. , Forster Robert , Vettenburg Tom
Published: June 2020

We demonstrate the first planar Airy light-sheet microscope. Fluorescence light-sheet microscopy has become the method of choice to study large biological samples with cellular or sub-cellular resolution. The propagation-invariant Airy beam enables a ten-fold increase in field-of-view with single-photon excitation; however, the characteristic asymmetry of the light-sheet limits its potential for multi-photon excitation. Here we show how a planar light-sheet can be formed from the curved propagation-invariant Airy beam. The resulting symmetric light sheet excites two-photon fluorescence uniformly across an extended field-of-view without the need for deconvolution. We demonstrate the method for rapid two-photon imaging of large volumes of neuronal tissue.
Virtualized EAST–WEST PON architecture supporting low-latency communication for mobile functional split based on multiaccess edge computing
Authors: Das Sandip , Slyne Frank , Kaszubowska Aleksandra , Ruffini Marco
Published: June 2020

Ultralow latency end-to-end communication with high reliability is one of the most important requirements in 5G networks to support latency-critical applications. A recent approach toward this target is to deploy edge computing nodes with networking capabilities, known as multiaccess edge computing (MEC), which can greatly reduce the service end-to-end latency. However, the use of MEC nodes poses radical changes to the access network architecture. This requires movement from the classical point-to-multipoint (or point-to-point) structure, used to deliver residential broadband and cloud radio access network (Cloud-RAN) services, to a mesh architecture that can fully embed the MEC nodes with all other end points (i.e., mobile cells, fixed residential, businesses). In this paper, we propose what we believe to be a novel passive optical network (PON)-based mobile fronthaul transport architecture based on PON virtualization that allows EAST–WEST communication along with traditional NORTH–SOUTH communication. The architecture enables the end points of a PON tree, where usually optical networking units (ONUs) are located, to also host MEC nodes by deploying an edge optical line terminal (OLT) capable of communicating directly with adjacent ONUs, by reflecting wavelength signals from the splitter nodes. We experimentally show that signal backscattering due to the reflection at the splitter does not affect the system performance. In addition, using protocol level simulations, we show how this architecture can maintain low latency (

≈

100

µ

s

) in varying mobile traffic conditions by offloading ONUs (i.e., where remote units of Cloud-RAN cells are located) to other edge OLTs through dynamic formation of virtual PON slices. Furthermore, our results show how an efficient migration strategy for ONUs can be chosen depending on the traffic load, different functional split configurations, and the PON capacity.
Rapid large-scale fabrication of multipart unit cell metasurfaces
Authors: Hemmati Hafez , Bootpakdeetam Pawarat , Lee Kyu Jin , Magnusson Robert
Published: June 2020

Periodic diffractive elements known as metasurfaces constitute platform technology whereby exceptional optical properties, not attainable by conventional means, are attained. Generally, with increasing unit-cell complexity, there emerges a wider design space and bolstered functional capability. Advanced devices deploying elaborate unit cells are typically generated by electron-beam patterning which is a tedious, slow process not suitable for large surfaces and quick turnaround. Ameliorating this condition, we present a novel route towards facile fabrication of complex periodic metasurfaces based on sequential exposures by laser interference lithography. Our method is fast, cost-effective, and can be applied to large surface areas. It is enabled by precise control over periodicity and exposure energy. With it we have successfully patterned and fabricated one-dimensional (1D) and two-dimensional (2D) multipart unit cell devices as demonstrated here. Thus, zero-order transmission spectra of an etched four-part 1D grating device are simulated and measured for both transverse-electric (TE) and transverse-magnetic (TM) polarization states of normally incident light. We confirm non-resonant wideband antireflection (∼800 nm) for TM-polarized light and resonance response for TE-polarized light in the near-IR band spanning 1400-2200 nm in a ∼100 mm2 device. Furthermore, it is shown that this method of fabrication can be implemented not only to pattern periodic symmetric/asymmetric designs but also to realize non-periodic metasurfaces. The method will be useful in production of large-area photonic devices in the realm of nanophotonics and microphotonics.
Tapered Yb-doped fiber enabled monolithic high-power linearly polarized single-frequency laser
Authors: Huang Long , Lai Wenchang , Ma Pengfei , Wang Jin , Su Rongtao , Ma Yanxing , Li Can , Zhi Dong , Zhou Pu
Published: June 2020

The all-fiber high-power linearly polarized single-frequency fiber laser based on the polarization-maintaining tapered Yb-doped fiber (T-YDF) is systematically studied. As a result, a 300 W-level stable output with linear polarization and nearly diffraction-limited beam quality is demonstrated. In particular, the overall properties of the transverse mode instability (MI) effect in such a single-frequency laser system are discussed in detail for the first time, to the best of our knowledge, including temporal, frequency, polarization, and spatial domains. Furthermore, the beam pointing error taking the MI effect into account is investigated. Theoretical analyses covering both stimulated Brillouin scattering and the MI effects reveal the great potential of the T-YDF for further power scaling as well.
Universal self-similar asymptotic behavior of optical bump spreading in a random medium atop incoherent background: comment
Authors: Charnotskii Mikhail
Published: June 2020

We show that the “intensity bump” cross-spectral density used in
Opt. Lett.
45, 698 (2020)OPLEDP0146-959210.1364/OL.385246 does not
satisfy the non-negative definiteness requirement and cannot be used
as a cross-spectral density model.
Phase-locked picosecond optical parametric oscillator
Authors: Nandy B. , Chaitanya Kumar S. , Ebrahim-Zadeh M.
Published: June 2020

We report a degenerate self-phase-locked picosecond optical parametric oscillator (OPO) synchronously pumped by a mode-locked Yb-fiber laser at 1064 nm, delivering broadband output near 2 µm with 2.8 W of average power at

∼

80

M
H
z

repetition rate. By exploiting a 50-mm-long MgO:PPLN crystal providing high gain and low group velocity dispersion under type-0 (

e
→
e
e

) phase matching, the OPO generates a phase-locked degenerate output spectrum with a bandwidth of

∼

202

n
m

centered at 2128 nm in pulses of

∼

21

p
s

duration with excellent passive long-term power and spectral stability in high spatial beam quality. Phase-locked operation results in spectral and power stabilization at exact degeneracy and is further validated by

f
−
2
f

interferometry and radio frequency measurements of OPO output. To the best of our knowledge, this is the first degenerate self-phase-locked OPO in picosecond time scale, and the highest average power reported for a phase-locked ultrafast OPO to date.
2 MW peak power generation in fluorine co-doped Yb fiber prepared by powder-sinter technology
Authors: Leich Martin , Kalide André , Eschrich Tina , Lorenz Martin , Lorenz Adrian , Wondraczek Katrin , Schönfeld Dörte , Langner Andreas , Schötz Gerhard , Jäger Matthias
Published: June 2020

We report on the first, to the best of our knowledge, implementation of a fluorine co-doped large-mode-area REPUSIL fiber for high peak power amplification in an ultrashort-pulse master oscillator power amplifier. The core material of the investigated step-index fiber with high Yb-doping level, 52 µm core and high core-to-clad ratio of 1:4.2 was fabricated by means of the REPUSIL powder-sinter technology. The core numerical aperture was adjusted by fluorine codoping to 0.088. For achieving high beam quality and for ensuring a monolithic seed path, the LMA fiber is locally tapered. We demonstrate an Yb fiber amplifier with near-diffraction-limited beam quality of

M

2

=

1.3

, which remains constant up to a peak power of 2 MW. This is a record for a tapered single core fiber.
Stable complex conjugate artifact removal in OCT using circularly polarized light as reference
Authors: Liu Xinyu , Ke Mengyuan , Yao Xinwen , Chua Jacqueline , Schmetterer Leopold , Tan Bingyao
Published: June 2020

In Fourier domain optical coherence tomography (FDOCT), the depth profile is mirrored about the zero delay between the sample and reference optical paths, limiting the imaging depth to half of the entire ranging space and undermining the optimal sensitivity window. We present a new method, to the best of our knowledge, to remove the complex conjugate artifact by using circularly polarized light as reference. Quadrature detection of the complex fringe is achieved by utilizing the intrinsic

λ

/

4

delay between two polarization channels. We use passive broadband polarization optics to control the polarization state of the light in the reference and sample arms and a balanced polarization diversity detection unit to simultaneously detect phase-shifted fringes. We demonstrate a 40 dB artifact suppression ratio with a swept-source optical coherence tomography system. Our proposed method is immune to sample motion and laser phase noise, and imposes no restrictions to the source bandwidth, imaging speed, or computational power. In vivo images of the human finger, as well as the cornea and retina of a non-human primate, were demonstrated.
Photopolymerization with high-order Bessel light beams
Authors: Arita Yoshihiko , Lee Junhyung , Kawaguchi Haruki , Matsuo Reimon , Miyamoto Katsuhiko , Dholakia Kishan , Omatsu Takashige
Published: June 2020

We study photopolymerization with high-order Bessel light beams with phase singularities on-axis. Self-trapping and self-focusing of propagation-invariant light beams in a photopolymer allow the fabrication of extended helical microfibers with a length scale of a centimeter, which is more than an order of magnitude larger than the propagation distance of the Bessel light beams. We show the evolution of microfibers rotating at a rate proportional to the incident optical power, while the periodicity of the helical structures remains constant, irrespective of the laser power. This suggests that optical momentum transfer plays a predominant role in the growth and rotation of such fiber structures.
Spontaneous four-wave mixing in silicon nitride waveguides for broadband coherent anti-Stokes Raman scattering spectroscopy
Authors: Lüpken Niklas M. , Würthwein Thomas , Epping Jörn P. , Boller Klaus-J. , Fallnich Carsten
Published: June 2020

We present a light source for coherent anti-Stokes Raman scattering (CARS) based on broadband spontaneous four-wave mixing, with the potential to be further integrated. By using 7 mm long silicon nitride waveguides, which offer tight mode confinement and a high nonlinear refractive index coefficient, broadband signal and idler pulses were generated with 4 nJ of input pulse energy. In comparison to fiber-based experiments, the input energy and the waveguide length were reduced by two orders of magnitude, respectively. The idler and residual pump pulses were used for CARS measurements, enabling chemically selective and label-free spectroscopy over the entire fingerprint region, with an ultrafast fiber-based pump source at 1033 nm wavelength. The presented simple light source paves the path towards cost-effective, integrated lab-on-a-chip CARS applications.
Rapid fabrication of high-resolution multi-scale microfluidic devices based on the scanning of patterned femtosecond laser
Authors: Zhang Chenchu , Zhang Jianming , Chen Renfei , Li Jiawen , Wang Chaowei , Cao Rui , Zhang Jingjing , Ye Hanchang , Zhai Hua , Sugioka Koji
Published: June 2020

Femtosecond-laser-induced two-photon polymerization has distinct
advantages in micro-nanofabrication due to its intrinsic
three-dimensional processing capability and high precision with
sub-100 nanometer fabrication resolution. However, the high resolution
causes a drawback in fabricating large-scale structures due to
unacceptably long processing times. To solve this problem, we applied
the patterned focus as the basic element for scanning processing.
Theoretically, the relationship between patterned-focus scanning
parameters and the uniformity of scanned light field was analyzed and
optimized. Experimentally, we quantitatively investigated the
relationship between the microstructure surface quality and the
parameters of patterned-focus scanning. Based on above, we put forward
a hybrid method that combines the femtosecond laser patterned exposure
with direct-writing fabrication to rapidly fabricate large-scale
microfluidic devices for various practical applications.
Vector partially coherent beams with prescribed non-uniform correlation structure
Authors: Yu Jiayi , Zhu Xinlei , Lin Shuqin , Wang Fei , Gbur Greg , Cai Yangjian
Published: June 2020

We introduce a general strategy for the synthesis of vector partially coherent beams (PCBs) with a prescribed non-uniform correlation structure. With it, we characterize a specific family of such beams, termed radially polarized Hermite non-uniformly correlated (RPHNUC) beams. These beams possess unusual propagation properties compared to vector PCBs with uniform correlation structure; for example, they maintain their dark hollow core and evolve multi-ring structures. These beams may prove useful in free-space optical communications, optical trapping, and polarization-sensitive imaging.
Straightforward nano patterning on optical fiber for sensors development
Authors: De Acha Nerea , Elía Víctor , Delgado-Camón Arantzazu , Arregui Francisco J. , Elosúa César
Published: June 2020

A simple method to prepare a nano pattern along the surface of an optical fiber is applied in this Letter to develop a pH sensor. The template is made of a block copolymer that defines specific locations where gold nano particles are adsorbed on forming clusters. The average diameter of the resulting agglomerates is 121 nm, and the mean distance between the centers is 182 nm. The morphology of the gold cluster array produces localized surface plasmon resonance. The absorbance spectrum is affected by pH variations, and the ratio between the absorption at two different wavelengths is used to characterize the response, which is repetitive and reversible. This Letter highlights the potentiality of this type of chemical nano patterning for the development of optical fiber sensors.
Few-cycle mid-infrared pulses from BaGa2GeSe6
Authors: Elu Ugaitz , Maidment Luke , Vamos Lenard , Steinle Tobias , Haberstroh Florian , Petrov Valentin , Badikov Valeriy , Badikov Dmitrii , Biegert Jens
Published: June 2020

B
a
G
a

2

G
e
S
e

6

(BGGSe) is a newly developed nonlinear material that is attractive for ultrabroad frequency mixing and ultrashort pulse generation due to its comparably low dispersion and high damage threshold. A numerical study shows the material’s capacity for octave-spanning mid-infrared pulse generation up to 18 µm. In a first experiment, we show that a long crystal length of 2.6 mm yields a pulse energy of 21 pJ at 100 MHz with a spectral bandwidth covering 5.8 to 8.5 µm. The electric field of the carrier-envelope-phase stable pulse is directly measured with electro-optical sampling and reveals a pulse duration of 91 fs, which corresponds to sub-four optical cycles, thus confirming some of the prospects of the material for ultrashort pulse generation and mid-infrared spectroscopy.
Secure BB84-type quantum key distribution with a simple phase error formula: retraction
Authors: Yin Hua-Lei , Chen Zeng-Bing
Published: June 2020

The referenced paper [Opt. Lett. 45, 1627
(2020)OPLEDP0146-959210.1364/OL.387877] has been retracted by
the authors.
Epitaxial superconducting tunnel diodes for light detection applications
Authors: Balasubramanian Krishna , Wright John , Zohar Orr , Taitler Boaz , Bouscher Shlomi , Xing Huili Grace , Jena Debdeep , Hayat Alex
Published: June 2020

We demonstrate epitaxially integrated nanoscale superconductor tunnel diodes, realized using NbN on GaN thin films. Tuning the growth conditions leads to reduced interface defect density and to the emergence of the superconducting coherence peaks in the interface tunneling characteristics. The degree of disorder in the superconductor is correlated with the variance in the order parameter value of different domains. Epitaxial integration of the nanoscale layers allowed precise control on the quality of the superconductor at the interface, and, by extension, the variance in the order parameter value. The numerical calculations taking a normal distribution of superconducting order parameter at the interface with a fixed variance in its order parameter values closely match the measured interface transport characteristics at different temperatures. Strong sub-gap nonlinearity observed in the differential conductivity measurements were subsequently shown to be sensitive to photon incidence, thereby acting as a photodetector. Usage of superconducting interfaces with semiconducting layers such as GaN permit sensitivity tunability and enable large scale device fabrication and integration.