bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between delay in intensive care unit admission and the host response in patients with community-acquired pneumonia
Authors: Pereverzeva Liza , Uhel Fabrice , Peters Sengers Hessel , Cremer Olaf L. , Schultz Marcus J. , Bonten Marc M. J. , Scicluna Brendon P. , van der Poll Tom ,   the MARS consortium
Published: September 2021

Background

A delay in admission to the intensive care unit (ICU) of patients with community-acquired pneumonia (CAP) has been associated with an increased mortality. Decisions regarding interventions and eligibility for immune modulatory therapy are often made at the time of admission to the ICU. The primary aim of this study was to compare the host immune response measured upon ICU admission in CAP patients admitted immediately from the emergency department (direct ICU admission) with those who were transferred within 72 h after admission to the general ward (delayed ICU admission).

Methods

Sixteen host response biomarkers providing insight in pathophysiological mechanisms implicated in sepsis and blood leukocyte transcriptomes were analysed in patients with CAP upon ICU admission in two tertiary hospitals in the Netherlands.

Results

Of 530 ICU admissions with CAP, 387 (73.0%) were directly admitted and 143 (27.0%) had a delayed admission. Patients with a delayed ICU admission were more often immunocompromised (35.0 versus 21.2%, P = .002) and had more malignancies (23.1 versus 13.4%, P = .011). Shock was more present in patients who were admitted to the ICU directly (46.6 versus 33.6%, P = .010). Delayed ICU admission was not associated with an increased hospital mortality risk (hazard ratio 1.25, 95% CI 0.89–1.78, P = .20). The plasma levels of biomarkers (n = 297) reflecting systemic inflammation, endothelial cell activation and coagulation activation were largely similar between groups, with exception of C-reactive protein, soluble intercellular adhesion molecule-1 and angiopoietin-1, which were more aberrant in delayed admissions compared to direct ICU admissions. Blood leukocyte transcriptomes (n = 132) of patients with a delayed ICU admission showed blunted innate and adaptive immune response signalling when compared with direct ICU admissions, as well as decreased gene expression associated with tissue repair and extracellular matrix remodelling pathways.

Conclusions

Blood leukocytes of CAP patients with delayed ICU admission show evidence of a more immune suppressive phenotype upon ICU admission when compared with blood leukocytes from patients directly transferred to the ICU.

Trial registration: Molecular Diagnosis and Risk Stratification of Sepsis (MARS) project, ClinicalTrials.gov identifier NCT01905033.
Local existence–uniqueness and monotone iterative approximation of positive solutions for p-Laplacian differential equations involving tempered fractional derivatives
Authors: Zhou Bibo , Zhang Lingling
Published: September 2021

In this paper, we are concerned with a kind of tempered fractional differential equation Riemann–Stieltjes integral boundary value problems with p-Laplacian operators. By means of the sum-type mixed monotone operators fixed point theorem based on the cone $P_{h}$

P
h

, we obtain not only the local existence with a unique positive solution, but also construct two successively monotone iterative sequences for approximating the unique positive solution. Finally, we present an example to illustrate our main results.
Determinants of influenza vaccine hesitancy among pregnant women in Europe: a systematic review
Authors: Adeyanju Gbadebo Collins , Engel Elena , Koch Laura , Ranzinger Tabea , Shahid Imtiaz Bin Mohammed , Head Micheal G. , Eitze Sarah , Betsch Cornelia
Published: September 2021

Background

Pregnant women are at high risk for severe influenza. However, maternal influenza vaccination uptake in most World Health Organization (WHO) European Region countries remains low, despite the presence of widespread national recommendations. An influenza vaccination reduces influenza-associated morbidity and mortality in pregnancy, as well as providing newborns with protection in their first months. Potential determinants of vaccine hesitancy need to be identified to develop strategies that can increase vaccine acceptance and uptake among pregnant women. The primary objective of the systematic review is to identify the individual determinants of influenza vaccine hesitancy among pregnant women in Europe, and how to overcome the hesitancy.

Methods

Databases were searched for peer-reviewed qualitative and quantitative studies published between 2009 and 2019 inclusive. Databases included PubMed via MEDLINE, Cochrane Central Register for Controlled Trials, PsycINFO, SAGE Journals, Taylor and Francis and Springer nature. These covered themes including psychology, medicine, and public health. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, 11 studies were eligible and analyzed for significant determinants of influenza vaccine hesitancy among pregnant women in Europe.

Results

The most commonly reported factors were psychological aspects, for example concerns about safety and risks to mother and child, or general low risk perception of becoming ill from influenza. Doubts about the effectiveness of the vaccine and a lack of knowledge about this topic were further factors. There was also influence of contextual factors, such as healthcare workers not providing adequate knowledge about the influenza vaccine or the pregnant lady stating their antivaccine sentiment.

Conclusion

Health promotion that specifically increases knowledge among pregnant women about influenza and vaccination is important, supporting a valid risk judgment by the pregnant lady. The development of new information strategies for dialogue between healthcare providers and pregnant women should form part of this strategy.
Novel multivalent design of a monoclonal antibody improves binding strength to soluble aggregates of amyloid beta
Authors: Rofo Fadi , Buijs Jos , Falk Ronny , Honek Ken , Lannfelt Lars , Lilja Anna M. , Metzendorf Nicole G. , Gustavsson Tobias , Sehlin Dag , Söderberg Linda , Hultqvist Greta
Published: September 2021

Background

Amyloid-β (Aβ) immunotherapy is a promising therapeutic strategy in the fight against Alzheimer’s disease (AD). A number of monoclonal antibodies have entered clinical trials for AD. Some of them have failed due to the lack of efficacy or side-effects, two antibodies are currently in phase 3, and one has been approved by FDA. The soluble intermediate aggregated species of Aβ, termed oligomers and protofibrils, are believed to be key pathogenic forms, responsible for synaptic and neuronal degeneration in AD. Therefore, antibodies that can strongly and selectively bind to these soluble intermediate aggregates are of great diagnostic and therapeutic interest.

Methods

We designed and recombinantly produced a hexavalent antibody based on mAb158, an Aβ protofibril-selective antibody. The humanized version of mAb158, lecanemab (BAN2401), is currently in phase 3 clinical trials for the treatment of AD. The new designs involved recombinantly fusing single-chain fragment variables to the N-terminal ends of mAb158 antibody. Real-time interaction analysis with LigandTracer and surface plasmon resonance were used to evaluate the kinetic binding properties of the generated antibodies to Aβ protofibrils. Different ELISA setups were applied to demonstrate the binding strength of the hexavalent antibody to Aβ aggregates of different sizes. Finally, the ability of the antibodies to protect cells from Aβ-induced effects was evaluated by MTT assay.

Results

Using real-time interaction analysis with LigandTracer, the hexavalent design promoted a 40-times enhanced binding with avidity to protofibrils, and most of the added binding strength was attributed to the reduced rate of dissociation. Furthermore, ELISA experiments demonstrated that the hexavalent design also had strong binding to small oligomers, while retaining weak and intermediate binding to monomers and insoluble fibrils. The hexavalent antibody also reduced cell death induced by a mixture of soluble Aβ aggregates.

Conclusion

We provide a new antibody design with increased valency to promote binding avidity to an enhanced range of sizes of Aβ aggregates. This approach should be general and work for any aggregated protein or repetitive target.
Laparoscopic approach for surgical treatment of pleuroperitoneal communication interfering with peritoneal dialysis: a case report
Authors: Yorinaga Satoko , Maki Takehiro , Kawai Noriko , Kaneko Hiroyuki , Misu Kenjiro , Inomata Hitoshi , Omi Makoto , Hirano Satoshi
Published: September 2021

Background

Pleuroperitoneal communication is a rare disorder that interferes with peritoneal dialysis. Although favorable results of thoracoscopic fistula closure have been reported, there are some cases in which the fistulas cannot be identified by thoracoscopy and the patients are forced to switch to hemodialysis.

Case presentation

We present two cases of pleuroperitoneal communication in which diaphragmatic fistulas could not be identified thoracoscopically, but could be identified laparoscopically. Patient 1 had difficulty continuing peritoneal dialysis 9 months after its introduction due to right pleural effusion. Although we could not detect the fistula thoracoscopically, we could laparoscopically identify the fistula in the center of the tendon of the right diaphragm and closed the site from the thoracic side. Patient 2 developed dyspnea due to right pleural effusion 6 months after the introduction of peritoneal dialysis. We could not find the fistulas with a thoracoscopic approach, but could identify multiple diaphragmatic fistulas with a laparoscopic approach and close the sites from the thoracic side.

Conclusion

In the surgical treatment of pleuroperitoneal communication, diaphragmatic fistulas can be identified laparoscopically even when thoracoscopic observation fails to find any fistulas.
Anesthetic implications and role of preoperative beta blockade in esophageal substitution with stomach in pediatric surgical patients
Authors: Kundal Raksha , Singh Ranju , Choudhury Subhasis Roy , Yadav Partap Singh , Kumar Ajai , Gupta Shalu , Kundal Vijay Kumar
Published: September 2021

Background

There is a paucity of literature on the anesthetic management of pediatric esophageal substitution using the stomach. We did a retrospective analysis of all such cases done at our institution. We analyzed the patient’s demography, indication, and type of surgery, co-morbid conditions, anesthesia techniques, duration of postoperative ventilation, hospital stay, complications, and mortality. The use of beta-blockers and their effect on the incidence of intraoperative and postoperative tachycardia in gastric pull-up patients was also analyzed.

Results

Thirty-four cases of gastric substitution of the esophagus in children were done over 19-year period; gastric pull-up was done in 28 patients and a gastric tube was made in 6 patients. General anesthesia was given to all; a thoracic epidural for pain was sited in 25 patients. Twenty-eight patients were ventilated postoperatively; the mean duration of ventilation is 54 h. Significant intraoperative tachycardia was observed in 85.7% of patients without beta-blocker as compared to 23.8% patients with beta-blocker (p = 0.004). Postoperatively, tachycardia was absent in patients receiving beta-blocker and present in 71.4% of patients not receiving beta-blockers (p < 0.001). Overall mortality was 8.8% but mortality due to cardiac arrhythmia was 42.9% in the patients not receiving beta-blockers (p = 0.001).

Conclusions

A thorough preoperative preparation, control of tachyarrhythmias, postoperative ventilation, and pain management is recommended for a favorable outcome. In addition, our paper supports the preoperative use of beta-blockers in reducing the incidence of fatal tachyarrhythmias associated with gastric pull-up surgery without any serious adverse effects.

Level of evidence

Level III
A dual-modality quantification of scattered radiation from head to female breasts during radiological investigations in a tertiary hospital in Nigeria
Authors: Adejoh Thomas , Ezugwu Emeka E. , Erondu Felix O. , Okeji Mark C. , Anumihe Peter-Damian O. , Asogwa Chijioke O.
Published: September 2021

Background

To quantify the amount of scattered radiation reaching the breasts during x-ray and CT investigations of the head in order to find appropriate justification for an intended change in practice involving torso shielding.

Results

Scattered radiation from the head reached the breasts in both procedures. The range and mean dose were (CR 1.02–3.61/1.94 ± 0.63 mGy) and (CT 2.20–8.50/3.74 ± 2.28 mGy). Both breasts had enormous dose difference in CR (72.3%) and CT (51.4%) which were statistically significant (p < 0.05). Correlation of dose with anthropometric parameters gave weak results.

Conclusion

Despite dose mitigation strategies such as software and hardware modifications in radiological modalities, use of anti-scatter grid, appropriate collimation and dose optimization by radiographers, scattered radiation still traveled from the head to the breasts. These were, however, significantly reduced when shielding was applied. For a dose-safe practice, radiographers are urged, in addition to current strategies at mitigating scatters, to adopt torso shielding during examinations involving contiguous anatomies to the breast.
Cholecysto-pyloric fistula with submucosal impaction of gall stone causing gastric outlet obstruction masquerading as a gastric mass, Bouveret Syndrome: case report
Authors: Meena Lokesh , Sharma Bhavya , Singh Ravi Shanker , Chauhan Udit , Matthew Anvin
Published: September 2021

Background

Cholecysto-enteric fistula is a rare complication of cholelithiasis and cholecystitis. Another even rarer complication is proximal impaction of gallstone(s) in gastric pylorus leading to gastric outlet obstruction, known as the Bouveret Syndrome. Only a few cases have been reported in the available literature. It can be confused with a malignant thickening at the pylorus, knowledge of this syndrome helps in arriving at the right diagnosis.

Case report

A 52-year-old female patient, who was admitted to our hospital for evaluation of recurrent vomiting and abdominal pain. She was investigated with various imaging modalities including upper gastrointestinal (GI) endoscopy, abdominal ultrasonography as well as Contrast Enhanced Computerized Tomography (CECT) scan of the abdomen. On the outside scan, it was given as a malignant thickening at the pylorus. However, current radiologists felt that imaging findings were not of a typical malignant mass, and suspicion of Bouveret syndrome was given. Intraoperative findings confirmed the diagnosis of Bouveret syndrome. The patient has not experienced any postoperative complications till now.

Conclusion

Bouveret syndrome is associated with significant morbidity and mortality. Being familiar with the imaging appearance of this condition, and differentiating it with malignant thickening can help radiologists avoid unnecessary invasive procedures in such patients. Being a benign etiology, it also helps in a better prognosis.
Pharmacological or genetic inhibition of hypoxia signaling attenuates oncogenic RAS-induced cancer phenotypes
Authors: Zhu Jun-yi , Huang Xiaohu , Fu Yulong , Wang Yin , Zheng Pan , Liu Yang , Han Zhe
Published: September 2021

Oncogenic Ras mutations are highly prevalent in hematopoietic malignancies. However, it is difficult to directly target oncogenic RAS proteins for therapeutic intervention. We have developed a Drosophila acute myeloid leukemia model induced by human KRASG12V, which exhibits a dramatic increase in myeloid-like leukemia cells. We performed both genetic and drug screens using this model. The genetic screen identified 24 candidate genes able to attenuate the oncogenic RAS-induced phenotype, including two key hypoxia pathway genes HIF1A and ARNT (HIF1B). The drug screen revealed that echinomycin, an inhibitor of HIF1A, can effectively attenuate the leukemia phenotype caused by KRASG12V. Furthermore, we showed that echinomycin treatment can effectively suppress oncogenic RAS-driven leukemia cell proliferation, using both human leukemia cell lines and a mouse xenograft model. These data suggest that inhibiting the hypoxia pathway could be an effective treatment approach and that echinomycin is a promising targeted drug to attenuate oncogenic RAS-induced cancer phenotypes.

This article has an associated First Person interview with the first author of the paper.
A higher mitochondrial content is associated with greater oxidative damage, oxidative defenses, protein synthesis and ATP turnover in resting skeletal muscle
Authors: Neurohr Julie M. , Paulson Erik T. , Kinsey Stephen T.
Published: September 2021

An unavoidable consequence of aerobic metabolism is the production of reactive oxygen species (ROS). Mitochondria have historically been considered the primary source of ROS; however, recent literature has highlighted the uncertainty in primary ROS production sites and it is unclear how variation in mitochondrial density influences ROS-induced damage and protein turnover. Fish skeletal muscle is composed of distinct, highly aerobic red muscle and anaerobic white muscle, offering an excellent model system in which to evaluate the relationship of tissue aerobic capacity and ROS-induced damage under baseline conditions. The present study used a suite of indices to better understand potential consequences of aerobic tissue capacity in red and white muscle of the pinfish, Lagodon rhomboides. Red muscle had a 7-fold greater mitochondrial volume density than white muscle, and more oxidative damage despite also having higher activity of the antioxidant enzymes superoxide dismutase and catalase. The dominant protein degradation system appears to be tissue dependent. Lysosomal degradation markers and autophagosome volume density were greater in white muscle, while ubiquitin expression and 20S proteasome activity were significantly greater in red muscle. However, ubiquitin ligase expression was significantly higher in white muscle. Red muscle had a more than 2-fold greater rate of translation and total ATP turnover than white muscle, results that may be due in part to the higher mitochondrial density and the associated increase in oxidative damage. Together, these results support the concept that an elevated aerobic capacity is associated with greater oxidative damage and higher costs of protein turnover.
Agglomeration, Misallocation, and (the Lack of) Competition
Authors: Brooks Wyatt J. , Kaboski Joseph P. , Li Yao Amber
Published: September 2021

Industrial agglomeration policies may limit competition. We develop, validate, and apply a novel approach for measuring competition based on the comovement of markups and market shares among firms in the same location and industry. Then we develop a model of how this reduction in competition affects aggregate income. We apply our approach to the well-known special economic zones (SEZs) of China. We estimate that firms in SEZs exhibit cooperative pricing almost three times as intensively as firms outside SEZs. Nevertheless, we model the aggregate consequences of SEZs and find positive effects because markups become higher but also more equal. (JEL D22, L60, O14, O18, P25, P31, R32)
Doublet identification in single-cell sequencing data using scDblFinder
Authors: Germain Pierre-Luc , Lun Aaron , Macnair Will , Robinson Mark D.
Published: September 2021

Doublets are prevalent in single-cell sequencing data and can lead to artifactual findings. A number of strategies have therefore been proposed to detect them. Building on the strengths of existing approaches, we developed scDblFinder, a fast, flexible and accurate Bioconductor-based doublet detection method. Here we present the method, justify its design choices, demonstrate its performance on both single-cell RNA and accessibility sequencing data, and provide some observations on doublet formation, detection, and enrichment analysis. Even in complex datasets, scDblFinder can accurately identify most heterotypic doublets, and was already found by an independent benchmark to outcompete alternatives.
Methods for living evidence synthesis: a systematic review protocol
Authors: Auladell-Rispau Ariadna , Bendersky Josefina , Santafe Angie , Buchanan Cecilia , Rigau Comas David , Verdugo Francisca , Ávila Camila , Alonso Pablo , Urrutia Gerard , Rada Gabriel , Rojas-Reyes María Ximena
Published: September 2021

Background: Living evidence (LE) refers to the methodological process that permits new research findings to be continually incorporated to evidence synthesis as they become available. This approach is of great value in the resolution of relevant and rapidly changing clinical questions. To date, the methods to carry out this type of synthesis are not completely defined, and great variability is observed in the approaches used by different groups of authors.

Objective: To identify and summarise the current methods used for living evidence synthesis.

Methods: We will conduct a systematic literature review of systematic reviews, overviews, and network metanalyses that have used “living evidence synthesis” as part of their methods. The search will be conducted in Medline (via PubMed) and the Epistemonikos database. Two reviewers will independently screen each article for eligibility, extract data, and assess the methodological quality standards of the study accordingly. This protocol is being registered in Prospero.
Manipulation and protection against manipulation in activities of the head of the internal affairs body of the Russian Federation
Authors: Vozzhenikova Ol'ga , Muhtarov Salavat
Published: September 2021

The aim of the research in this work is to study the features of psychological manipulation and ways to neutralize it as components of the activities of the heads of the internal affairs body of the Russian Federation. The phenomenon of "manipulation" has been studied by researchers in this field for a long time. In general terms, it means a sequence of some intentions and actions, the final result of which is not obvious to those to whom it is directed. The development of the global information and communication environment makes various theoretical and applied knowledge of a specific property available to a wide range of people and creates favorable conditions for the use of this knowledge for the purpose of manipulation and manipulative influence on certain social groups, entire social systems and their individual representatives. By the nature of their activities, the heads of the internal affairs bodies of the Russian Federation often have to deal with psychological manipulation, the involvement in which is related to official necessity. A study (survey) was carried out with the participation of 50 students of the management faculty of the Academy of Management of the Ministry of Internal Affairs of Russia aged 30 to 55 years, the purpose of which was to study the features of psychological manipulation in the activities of the head of the internal affairs body of the Russian Federation. The results of the study showed that there is a need to develop the manager's competence in the field of manipulative influence. Today in psychological science and practice there are many technologies for the use, recognition and protection from psychological manipulations, which can be successfully used by the heads of the internal affairs bodies of the Russian Federation in managerial activities, but this requires special training from them.
Method of automatic correction of neutron monitor data for precipitation in the form of snow in real time
Authors: Yanchukovsky Valery , Kuz'menko Vasiliy
Published: September 2021

We have carried out an experimental study of the influence of precipitation in the form of snow on measurements of the neutron flux intensity near Earth's surface. We have examined the state of the snow cover and its density, and found out that the density depends on the depth of the snow cover. Using the experimental results, we estimate the neutron absorption path in the snow. Changes in snow cover by 10–12 cm at a depth of 80 cm are shown to cause variations in the monitor count rate with an amplitude of 0.9 %. At the snow depth of 80 cm, the neutron monitor count rate decreases by about 8 %. The observed variations should be attributed to the meteorological effects of cosmic rays. The absorption coefficient of neutrons in the snow was also found from the correlation between the count rate of the neutron monitor and the amount of snow above the detector. We propose a real-time correction of the neutron monitor data for precipitation in the form of snow. For this purpose, we implement continuous monitoring of the amount of snow cover. The monitoring is provided by a snow meter made using a laser rangefinder module. We discuss the results obtained.
People-centred care
Authors: Forsythe Gemma
Published: September 2021

Gemma Forsythe discusses caring for those with additional support needs
The first rule of prevention
Authors: Alcraft Tom
Published: September 2021

Tom Alcraft explains why toothbrushing should be a main focus
Banking on your workers: avoid falling foul of employment legislation
Authors: Gordon Lucy
Published: September 2021

Bank workers are often what keep care services in operation, covering recruitment vacancies, staff holidays and sickness, and less popular shifts. They are your flexible, readily available resource, but are you ensuring that you comply with the frequently changing rules and entitlements for casual staff, and could the current market make this resource harder to obtain? Lucy Gordon investigates.
Antioxidant Efficiency of Irganox® 1010 on Processing and Properties of Plasticized Poly(3-Hydroxybutyrate) Films
Authors: Quispe Mayte M. , López Olivia V. , Villar Marcelo A.
Published: September 2021

Polyhydroxybutyrate (PHB) is one of the few biopolymers that can be processed at industrial scale. Nevertheless, PHB applications in film form are limited, mainly due to the high biopolymer crystallinity and its narrow thermal processing window. In this work, it was studied the effect of glycerol tributyrate (GTB) incorporation as plasticizer, in addition to Irganox® 1010 (I) as phenolic antioxidant on the processability and final properties of PHB-based films. PHB was melt processed in the presence of GTB (5-30 %w/w, PHB basis) and Irganox® (0.3 %w/w, PHB basis) and films were obtained by thermo-compression. PHB films without the plasticizer and the antioxidant were used as control sample. Thermal properties of films demonstrated that PHB thermal processing window was increased due to a synergistic effect of both additives. Improvement can be attributed to changes in the crystalline structure corroborated by X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). Oxygen Transmission Rate (OTR) of PHB films increased in the presence of GTB and Irganox due to the crystalline changes induced by both additives.
Intent-based networking and its application to optical networks [Invited Tutorial]
Authors: Velasco L. , Barzegar S. , Tabatabaeimehr F. , Ruiz M.
Published: September 2021

The intent-based networking (IBN) paradigm targets defining high-level abstractions so network operators can define what their desired outcomes are without specifying how they would be achieved. The latter can be achieved by leveraging network programmability, monitoring, and data analytics, as well as the key assurance component. In this tutorial, we introduce the IBN paradigm and its application to optical networking, highlighting the benefits that machine learning (ML) algorithms can provide to IBN. Because the deployment of ML applications requires a specific orchestrator to create ML functions that are connected as ML pipelines, we show an implementation of such an orchestrator. Some challenges and solutions are presented for the generation of accurate synthetic data, proactive self-configuration, and cooperative intent operation. Illustrative examples of intent-based operation and numerical results are presented, and the obtained performance is discussed.
Two-photon dual-comb LiDAR
Authors: Wright Hollie , Sun Jinghua , McKendrick David , Weston Nick , Reid Derryck T.
Published: September 2021

The interferometric signals produced in conventional dual-comb laser ranging require femtosecond lasers with long-term carrier-envelope offset frequency stability, and are limited to an upper sampling rate by radio-frequency aliasing considerations. By using cross-polarized dual combs and two-photon detection, we demonstrate carrier-phase-insensitive cross-correlations at sampling rates of up to 12× the conventional dual-comb aliasing limit, recording these in a digitizer-based acquisition system to implement ranging with sub-100 nm precision. We then extend this concept to show how the high data burden of conventional dual-comb acquisition can be eliminated by using a simple microcontroller as a ns-precision stopwatch to record the time intervals separating the two-photon cross-correlation pulses, providing real-time and continuous LiDAR-like distance metrology capable of sub-100 nm precision and dynamic acquisition for unlimited periods.
Generation of 64-fs L-band stretched pulses from an all-fibre Er-doped laser
Authors: Huang Zinan , Boscolo Sonia , Huang Qianqian , Xing Zhikun , Yan Zhijun , Chen Tao , Liu Yunqi , Mou Chengbo
Published: September 2021

We demonstrate an L-band all-fibre erbium-doped laser mode locked by nonlinear polarisation rotation and working in the stretched-pulse regime. The use of a single segment of gain fibre with appropriate length and dispersion and a Brewster fibre grating optimised for the L band as an in-fibre polariser enables the generation of pulses at 1.59-μm central wavelength, which can be linearly compressed to 64-fs duration. Numerical simulations of the laser model support our experimental findings. Our laser design gives a route towards low-cost and low-complexity fibre-integrated laser sources for applications requiring L-band ultrashort pulses.
Absolute spectral backscatter measurements of large-core multimode PMMA polymer optical fibers
Authors: Dengler Simon A. , Engelbrecht Rainer , Schmauss Bernhard
Published: September 2021

To our knowledge, we are the first to measure the absolute value of the backscattering coefficient of a standard 1 mm core-diameter, multimode (MM) step-index (SI) polymethylmethacrylate (PMMA) polymer optical fiber (POF) for the spectral range of 450 nm to 700 nm. Our optical time domain reflectometer (OTDR) setup consists of a femtosecond supercontinuum laser with an acousto-optical filter as a tunable light source with short pulses and a time-correlated single-photon counting system as a receiver with a high dynamic range. The backscattering coefficient is calculated from the ratio between the energy within the fiber end reflex and the distributed backscattering level. We also measured the spectral attenuation with our OTDR setup and compared it with a standardized measurement method. At the attenuation minima within the measured spectral range the backscattering level of a 1 ns pulse is about −46 dB at 520 nm, −48 dB at 570 nm, and −51 dB at 650 nm. We were also able to show by the observed wavelength dependence that Rayleigh scattering causes a majority of the scattering.
Spin memory effect in charged single telecom quantum dots
Authors: Podemski Paweł , Gawełczyk Michał , Wyborski Paweł , Salamon Hanna , Burakowski Marek , Musiał Anna , Reithmaier Johann Peter , Benyoucef Mohamed , Sęk Grzegorz
Published: September 2021

Single InP-based quantum dots emitting in the third telecom window are probed quasi-resonantly in polarization-resolved microphotoluminescence experiments. For charged quantum dots we observe negative circular polarization being a fingerprint of the optical spin writing of the carriers within the quantum dots. The investigated quantum dots have a very dense ladder of excited states providing relatively easy quasi-resonant optical excitation, and together with telecom wavelengths emission they bring quantum gates and memories closer to compatibility with fiber-optic communication.
3D light-field display with an increased viewing angle and optimized viewpoint distribution based on a ladder compound lenticular lens unit
Authors: Liu Li , Sang Xinzhu , Yu Xunbo , Gao Xin , Wang Yuedi , Pei Xiangyu , Xie Xinhui , Fu Bangshao , Dong Haoxiang , Yan Binbin
Published: September 2021

Three-dimensional (3D) light-field displays (LFDs) suffer from a narrow viewing angle, limited depth range, and low spatial information capacity, which limit their diversified application. Because the number of pixels used to construct 3D spatial information is limited, increasing the viewing angle reduces the viewpoint density, which degrades the 3D performance. A solution based on a holographic functional screen (HFS) and a ladder-compound lenticular lens unit (LC-LLU) is proposed to increase the viewing angle while optimizing the viewpoint utilization. The LC-LLU and HFS are used to create 160 non-uniformly distributed viewpoints with low crosstalk, which increases the viewpoint density in the middle viewing zone and provides clear monocular depth cues. The corresponding coding method is presented as well. The optimized compound lenticular lens array can balance between suppressing aberration and improving displayed quality. The simulations and experiments show that the proposed 3D LFD can present natural 3D images with the right perception and occlusion relationship within a 65° viewing angle.
Enhancement of image sharpness and height measurement using a low-speckle light source based on a patterned quantum dot film in dual-wavelength digital holography
Authors: Jang Se Hwan , Kim Ki Baek , Jung JuWon , Kim Young-Joo
Published: September 2021

A dual-wavelength single light source based on a patterned quantum dot (QD) film was developed with a 405nm LED and bandpass filters to increase color conversion efficiency as well as to decouple the two peaks of dual-wavelength emitted from the QD film. A QD film was patterned laterally with two different sizes of QDs and was combined with bandpass filters to produce a high efficiency and low-speckle dual-wavelength light source. The experimental results showed that the developed dual-wavelength light source can decrease speckle noise to improve the reconstructed image sharpness and the accuracy on height measurement in dual-wavelength digital holography.
Improved optical camera communication systems using a freeform lens
Authors: Liu Ziwei , Yang Lin , Yang Yanbing , Wu Rengmao , Zhang Lei , Chen Liangyin , Wu Die , She Jun
Published: September 2021

Optical camera communication (OCC) systems, which utilize image sensors embedded in commercial-off-the-shelf devices to detect time and spatial variations in light intensity for enabling data communications, have stirred up researchers’ interest. Compared to a direct OCC system whose maximum data rate is strongly determined by the LED source size, a reflected OCC system can break that limitation since the camera captures the light rays reflecting off an observation plane (e.g., a wall) instead of those light rays directly emanated from the light source. However, the low signal-to-noise ratio caused by the non-uniform irradiance distribution produced by LED luminaire on the observation plane in current reflected OCC systems cannot be avoided, hence low complexity and accurate demodulation are hard to achieve. In this paper, we present a FreeOCC system, which employs a dedicatedly tailored freeform lens to precisely control the propagation of modulated light. A desired uniform rectangular illumination is produced on the observation plane by the freeform lens, yielding a uniform grayscale distribution within the received frame captured by the camera in the proposed FreeOCC system. Then, the received signal can be easily demodulated with high accuracy by a simple thresholding scheme. A prototype of the FreeOCC system demonstrates the high performance of the proposed system, and two pulse amplitude modulation schemes (4-order and 8-order) are performed. By using the freeform lens, the packet reception rate is increased by 35% and 32%, respectively; the bit error rate is decreased by 72% and 59%, respectively, at a transmission frequency of 5 kHz. The results clearly show that the FreeOCC system outperforms the common reflected OCC system.
Enhanced light-extraction efficiency and emission directivity in compact photonic-crystal based AlGaInP thin-films for color conversion applications
Authors: Ndiaye Amade , Ghazouani Ahlem , Seassal Christian , Drouard Emmanuel , Olivier Nicolas , Bakir Badhise Ben
Published: September 2021

We investigated the use of photonic crystals with different opto-geometrical parameters for light extraction from AlGaInP/InGaP MQW color converters. Blue-to-red and green-to-red color conversions were demonstrated using room-temperature photoluminescence with excitation wavelengths at 405nm and 514nm. Complete, compact and highly directional light extraction was demonstrated. 3D-FDTD and a herein-developed phenomenological model derived from the standard coupled-mode theory were used to analyze the results. The highest light extraction gains were ∼8 times better than unpatterned reference structures, which were paired with short extraction lengths (between 2µm and 6µm depending on the acceptance angle) and directional light emission for square lattice of nanopillars with a lattice period of 400nm. The design guidelines set in this work could pave the way for the use of inorganic MQW epi-layer color converters to achieve full color microdisplays on a single wafer.
Improved temporal contrast of streak camera measurements with periodic shadowing
Authors: Bao Yupan , Kornienko Vassily , Lange David , Kiefer Wolfgang , Eschrich Tina , Jäger Matthias , Bood Joakim , Kristensson Elias , Ehn Andreas
Published: September 2021

Periodic shadowing, a concept used in spectroscopy for stray light reduction, has been implemented to improve the temporal contrast of streak camera imaging. The capabilities of this technique are first proven by imaging elastically scattered picosecond laser pulses and are further applied to fluorescence lifetime imaging, where more accurate descriptions of fluorescence decay curves were observed. This all-optical approach can be adapted to various streak camera imaging systems, resulting in a robust technique to minimize space-charge induced temporal dispersion in streak cameras while maintaining temporal coverage and spatial information.
Generation of wavelength-tunable few-cycle pulses in the mid-infrared at repetition rates up to 10  kHz
Authors: Sanari Yasuyuki , Sekiguchi Fumiya , Nakagawa Kotaro , Ishii Nobuhisa , Kanemitsu Yoshihiko , Hirori Hideki
Published: September 2021

We demonstrate a compact and tunable mid-infrared light source that
provides carrier-envelope-phase (CEP)-locked pulses at repetition
rates from 500 Hz to 10 kHz. The seed pulses were generated by
intra-pulse difference frequency mixing of the output of an Yb:KGW
regenerative amplifier that had been spectrally broadened by continuum
generation using multiple plates. Then, a two-stage optical parametric
amplifier was used to obtain output energies of about 100 µJ/pulse for
center wavelengths between 2.8 and 3.5 µm. Owing to the intense pulse
energies, it was possible to compress the multi-cycle pulses down to
two-cycle pulses using YAG and Si plates.
Combined multi-band infrared camouflage and thermal management via a simple multilayer structure design
Authors: Wang Lei , Yang Yue , Tang Xianglin , Li Bin , Hu Yizhi , Zhu Yonggang , Yang Huizhu
Published: September 2021

Infrared camouflage is crucial for high-temperature objects to avoid detection, and spontaneous infrared radiation is also an important way for high-temperature objects to dissipate heat. Therefore, selective infrared emission has become significant for the coating design of surfaces such as aircraft, which require low emission in the atmospheric window band (3–5 µm and 8–14 µm) and high emission outside it (5–8 µm). This Letter employs a simple multilayer film structure to achieve selective regulation of the material emission spectrum. Combining the transfer matrix method and genetic algorithm, a multilayer film structure containing 12 layers of three high-temperature-resistant materials (

S
i
O

2

,

T
i
O

2

and Ge) has been designed. It shows fairly low emissivity in two main bands of infrared detection (

ε

3
∼
5

µ

m

=

0.14

,

ε

8
∼
14

µ

m

=

0.21

) and high emissivity outside them (

ε

5
∼
8

µ

m

=

0.86

), and this infrared selectivity can be well maintained with the incident angle rising from 0 to 60 deg. The Poynting vector distribution in the material at different incident wavelengths is analyzed to further explore the interference mechanism to achieve spectral selective emission. The significance of this work lies in the construction of a relatively simple coating design while ensuring efficient infrared camouflage and thermal management performance.
Electrically driven transport of photoinduced hot carriers in carbon nanotube fibers
Authors: Liu Yu , Hu Qianqian , Wang Pengfei , Wei Jinquan , Huang Feng , Sun Jia-Lin
Published: September 2021

Hot carriers play a significant role in applications of photovoltaics, photodetection, and photocatalysis. However, effective methods for observing the ultrafast dynamic processes of hot carriers are concentrated on the time domain, on which it is difficult and complex to operate. We propose a novel, to the best of our knowledge, and creative strategy to convert the time-domain dynamic process into a spatially thermal redistribution in suspended carbon nanotube fibers. The large average free path of photoinduced hot holes ensures a prominent offset of temperature distribution. The experimental results confirm the theory about electrically driven transport of hot holes, which has rarely been reported.
Kompetenzorientiertes E-Assessment für die grafische, konzeptuelle Modellierung
Authors: Striewe Michael , Forell Martin , Houy Constantin , Pfeiffer Peter , Schiefer Gunther , Schüler Selina , Soyka Chantal , Stottrop Tobias , Ullrich Meike , Fettke Peter , Loos Peter , Oberweis Andreas , Schaper Niclas
Published: September 2021

In vielen Bereichen der Wirtschaftsinformatik spielt die Erstellung konzeptueller Modelle unter Verwendung grafischer Modellierungssprachen eine wichtige Rolle. Entsprechend wichtig ist eine fundierte Grundausbildung, die sich an den benötigten Modellierungskompetenzen orientiert und daher neben theoretischen auch praktische Aspekte der konzeptuellen Modellierung in den Blick nimmt. Der vorliegende Beitrag stellt erste Ergebnisse aus dem KEA-Mod-Projekt vor, das sich mit der Erstellung eines „digitalen Fachkonzepts“ im Bereich der grafischen, konzeptuellen Modellierung befasst. Kernstück dieses Fachkonzepts ist die Unterstützung der Grundausbildung in der grafischen, konzeptuellen Modellierung durch eine kompetenzorientierte E‑Assessment-Plattform mit automatisierten und individuellen Bewertungs- und Feedbackmöglichkeiten.
Identifying and prioritizing potential human-infecting viruses from their genome sequences
Authors: Mollentze Nardus , Babayan Simon A. , Streicker Daniel G.
Published: September 2021

Determining which animal viruses may be capable of infecting humans is currently intractable at the time of their discovery, precluding prioritization of high-risk viruses for early investigation and outbreak preparedness. Given the increasing use of genomics in virus discovery and the otherwise sparse knowledge of the biology of newly discovered viruses, we developed machine learning models that identify candidate zoonoses solely using signatures of host range encoded in viral genomes. Within a dataset of 861 viral species with known zoonotic status, our approach outperformed models based on the phylogenetic relatedness of viruses to known human-infecting viruses (area under the receiver operating characteristic curve [AUC] = 0.773), distinguishing high-risk viruses within families that contain a minority of human-infecting species and identifying putatively undetected or so far unrealized zoonoses. Analyses of the underpinnings of model predictions suggested the existence of generalizable features of viral genomes that are independent of virus taxonomic relationships and that may preadapt viruses to infect humans. Our model reduced a second set of 645 animal-associated viruses that were excluded from training to 272 high and 41 very high-risk candidate zoonoses and showed significantly elevated predicted zoonotic risk in viruses from nonhuman primates, but not other mammalian or avian host groups. A second application showed that our models could have identified Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) as a relatively high-risk coronavirus strain and that this prediction required no prior knowledge of zoonotic Severe Acute Respiratory Syndrome (SARS)-related coronaviruses. Genome-based zoonotic risk assessment provides a rapid, low-cost approach to enable evidence-driven virus surveillance and increases the feasibility of downstream biological and ecological characterization of viruses.
Drought and child vaccination coverage in 22 countries in sub-Saharan Africa: A retrospective analysis of national survey data from 2011 to 2019
Authors: Nagata Jason M. , Epstein Adrienne , Ganson Kyle T. , Benmarhnia Tarik , Weiser Sheri D.
Published: September 2021

Background

Extreme weather events, including droughts, are expected to increase in parts of sub-Saharan Africa and are associated with a number of poor health outcomes; however, to the best of our knowledge, the link between drought and childhood vaccination remains unknown. The objective of this study was to evaluate the relationship between drought and vaccination coverage.

Methods and findings

We investigated the association between drought and vaccination coverage using a retrospective analysis of Demographic and Health Surveys data in 22 sub-Saharan African countries among 137,379 children (50.4% male) born from 2011 to 2019. Drought was defined as an established binary variable of annual rainfall less than or equal to the 15th percentile relative to the 29 previous years, using data from Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) data. We evaluated the association between drought at the date of birth and receipt of bacillus Calmette–Guérin (BCG), diphtheria–pertussis–tetanus (DPT), and polio vaccinations, and the association between drought at 12 months of age and receipt of measles vaccination. We specified logistic regression models with survey fixed effects and standard errors clustered at the enumeration area level, adjusting for child-, mother-, and household-level covariates and estimated marginal risk differences (RDs). The prevalence of drought at date of birth in the sample was 11.8%. Vaccination rates for each vaccination ranged from 70.6% (for 3 doses of the polio vaccine) to 86.0% (for BCG vaccination); however, only 57.6% of children 12 months and older received all recommended doses of BCG, DPT, polio, and measles vaccinations. In adjusted models, drought at date of birth was negatively associated with BCG vaccination (marginal RD = −1.5; 95% CI −2.2, −0.9), DPT vaccination (marginal RD = −1.4; 95% CI −2.2, −0.5), and polio vaccination (marginal RD = −1.3; 95% CI −2.3, −0.3). Drought at 12 months was negatively associated with measles vaccination (marginal RD = −1.9; 95% CI −2.8, −0.9). We found a dose–response relationship between drought and DPT and polio vaccinations, with the strongest associations closest to the timing of drought. Limitations include some heterogeneity in findings across countries.

Conclusions

In this study, we observed that drought was associated with lower odds of completion of childhood BCG, DPT, and polio vaccinations. These findings indicate that drought may hinder vaccination coverage, one of the most important interventions to prevent infections among children. This work adds to a growing body of literature suggesting that health programs should consider impacts of severe weather in their programming.