bluuebunny/crossref_metadata_2025 huggingface dataset:
Falls and fear of falling among Israeli community-dwelling older people: a cross-sectional national survey
Authors: Frankenthal Dvora , Saban Mor , Karolinsky Dolev , Lutski Miri , Sternberg Shelley , Rasooly Iris , Laxer Irit , Zucker Inbar
Published: April 2021

Background

Falls and fear of falling are a major problem for older people and a leading cause of functional decline and institutionalization. There is limited data on the prevalence of falls in a 12-month period among Israeli older adults. Our main objective was to evaluate the prevalence of falls among Israeli community-dwelling older people aged ≥65 years and to identify factors associated with falls and fear of falling.

Methods

A national cross-sectional interview survey was conducted between February 2018 and April 2019 by the Israeli Center for Disease Control. The prevalence of falls was assessed by asking participants about falling within the 12 months prior to the survey. Fear of falling was assessed by asking participants about the fear of future falls. Multivariate analysis was used to identify factors associated with falls and with fear of falling.

Results

From 5281 households that were eligible for inclusion in this study, 3242 participants (61.4%) completed the survey. Falling at least once in the past year was reported by 23.8% of the respondents and fear of falling by 48.2%. The majority of the participants (91.1%) reported that they had never received any instruction about fall prevention from their medical care provider. In the multivariate analysis, falls and fear of falling were each a risk factor for the other; and were also significantly associated with female gender, major functional difficulties, the use of walking aids, cardiac disease, diabetes mellitus and psychotropic medications.

Conclusion

The prevalence of falls and fear of falling among Israeli community-dwelling older people is comparable to the rates published in other countries. Efforts should be made to increase awareness about falls and their health consequences among older people. The development of specific interventions to target those at higher risk for falls and fear of falling is strongly recommended.
Effect of gut microbiota modulation on feeding tolerance of enterally fed critically ill adult patients: a systematic review
Authors: Seifi Najmeh , Jafarzadeh Esfahani Ali , Sedaghat Alireza , Rezvani Reza , Khadem-Rezaiyan Majid , Nematy Mohsen , Safarian Mohammad
Published: April 2021

Purpose

The objective of this systematic review was to evaluate the effect of pre-, pro-, and synbiotics on feeding tolerance of enterally fed critically ill adult patients.

Methods

MEDLINE, Science Direct, Web of Knowledge, and the Cochrane Central Register of Controlled Trials were searched up to November 2019. English language randomized controlled trials reporting the effect of pre, pro or synbiotics on the feeding tolerance of enterally fed critically ill adult patients were included.

Results

Overall, 15 papers were selected for review. Among six studies reporting the energy intake, only two studies showed significantly higher energy intake in the prebiotic-receiving groups. Among four RCTs reporting frequency or time to achieve the target calorie, only one found a significant effect of probiotics to reduce the time to achieve a target dose of calorie. About the prevalence or duration of diarrhea, 7 out of 12 RCTs reported a beneficial effect. All but one study found no beneficial effects for gut microbiota manipulation on clinical endpoints including length of stay (LOS) in hospital and intensive care unit (ICU).

Conclusion

It should be noticed that the heterogeneity in study designs, product format, and ICU patient populations makes it difficult to draw any general conclusion. Overall, it seems that pre, pro, or synbiotics have no significant beneficial effect on feeding tolerance and clinical endpoints in critically ill adults, but they may reduce the prevalence or duration of diarrhea.
25 Years of the International Bipolar Collaborative Network (BCN)
Authors: Post Robert M. , Altshuler Lori L. , Kupka Ralph , McElroy Susan L. , Frye Mark A. , Grunze Heinz , Suppes Trisha , Keck Paul E. , Nolen Willem A.
Published: April 2021

Background

The Stanley Foundation Bipolar Treatment Outcome Network (SFBN) recruited more than 900 outpatients from 1995 to 2002 from 4 sites in the United States (US) and 3 in the Netherlands and Germany (abbreviated as Europe). When funding was discontinued, the international group of investigators continued to work together as the Bipolar Collaborative Network (BCN), publishing so far 87 peer-reviewed manuscripts. On the 25th year anniversary of its founding, publication of a brief summary of some of the major findings appeared appropriate. Important insights into the course and treatment of adult outpatients with bipolar disorder were revealed and some methodological issues and lessons learned will be discussed.

Results

The illness is recurrent and pernicious and difficult to bring to a long-term remission. Virtually all aspects of the illness were more prevalent in the US compared to Europe. This included vastly more patients with early onset illness and those with more psychosocial adversity in childhood; more genetic vulnerability; more anxiety and substance abuse comorbidity; more episodes and rapid cycling; and more treatment non-responsiveness.

Conclusions

The findings provide a road map for a new round of much needed clinical treatment research studies. They also emphasize the need for the formation of a new network focusing on child and youth onset of mood disorders with a goal to achieve early precision diagnostics for intervention and prevention in attempting to make the course of bipolar illness more benign.
Sensitivity of migratory connectivity estimates to spatial sampling design
Authors: Vickers Stephen H. , Franco Aldina M. A. , Gilroy James J.
Published: April 2021

Background

The use of statistical methods to quantify the strength of migratory connectivity is commonplace. However, little attention has been given to their sensitivity to spatial sampling designs and scales of inference.

Methods

We examine sources of bias and imprecision in the most widely used methodology, Mantel correlations, under a range of plausible sampling regimes using simulated migratory populations.

Results

As Mantel correlations depend fundamentally on the spatial scale and configuration of sampling, unbiased inferences about population-scale connectivity can only be made under certain sampling regimes. Within a contiguous population, samples drawn from smaller spatial subsets of the range generate lower connectivity metrics than samples drawn from the range as a whole, even when the underlying migratory ecology of the population is constant across the population. Random sampling of individuals from contiguous subsets of species ranges can therefore underestimate population-scale connectivity. Where multiple discrete sampling sites are used, by contrast, overestimation of connectivity can arise due to samples being biased towards larger between-individual pairwise distances in the seasonal range where sampling occurs (typically breeding). Severity of all biases was greater for populations with lower levels of true connectivity. When plausible sampling regimes were applied to realistic simulated populations, accuracy of connectivity measures was maximised by increasing the number of discrete sampling sites and ensuring an even spread of sites across the full range.

Conclusions

These results suggest strong potential for bias and imprecision when making quantitative inferences about migratory connectivity using Mantel statistics. Researchers wishing to apply these methods should limit inference to the spatial extent of their sampling, maximise their number of sampling sites, and avoid drawing strong conclusions based on small sample sizes.
Ultrasmall iron oxide nanoparticles induced ferroptosis via Beclin1/ATG5-dependent autophagy pathway
Authors: Wen Jian , Chen Hanren , Ren Zhongyu , Zhang Peng , Chen Jianjiao , Jiang Shulian
Published: April 2021

Iron-based nanoparticles, which could elicit ferroptosis, is becoming a promising new way to inhibit tumor cell growth. Notably, ultrasmall iron oxide nanoparticles (USIONPs) have been found to upregulate the autophagy process in glioblastoma (GBM) cells. Whether USIONPs could also elicit ferroptosis and the relationship between the USIONPs-induced autophagy and ferroptosis need to be explored. In the current study, our synthesized USIONPs with good water solubility could significantly upregulate the ferroptosis markers in GBM cells, and downregulate the expression of anti-ferroptosis genes. Interestingly,ferrostatin-1 could reverse USIONPs- induced ferroptosis, but inhibitors of apoptosis, pyroptosis, or necrosis could not. Meanwhile, autophagy inhibitor 3-methyladenine could also reverse the USIONPs-induced ferroptosis. In addition, shRNA silencing of upstream genes Beclin1/ATG5 of autophagy process could significantly reverse USIONPs-induced ferroptosis, whereas overexpression of Beclin1/ATG5 of autophagy process could remarkably promote USIONPs-induced ferroptosis. Furthermore, lysosome inhibitors could significantly reverse the USIONPs-induced ferroptosis. Collectively, these facts suggest that USIONPs-induced ferroptosis is regulated via Beclin1/ATG5-dependent autophagy pathway.
Recovery and evaluation of cellulose from agroindustrial residues of corn, grape, pomegranate, strawberry-tree fruit and fava
Authors: Vallejo Mariana , Cordeiro Rachel , Dias Paulo A. N. , Moura Carla , Henriques Marta , Seabra Inês J. , Malça Cândida Maria , Morouço Pedro
Published: April 2021

Considering the expected increasing demand for cellulose fibers in the near future and that its major source is wood pulp, alternative sources such as vegetable wastes from agricultural activities and agro-food industries are currently being sought to prevent deforestation. In the present study, cellulose was successfully isolated from six agroindustrial residues: corncob, corn husk, grape stalk, pomegranate peel, marc of strawberry-tree fruit and fava pod. Cellulose fibers were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, stereomicroscopy and scanning electron microscopy (SEM). Despite the evident morphological differences among the extracted celluloses, results revealed similar compositional and thermal properties with the wood-derived commercial microcrystalline cellulose used as a control. Trace amounts of lignin or hemicellulose were detected in all cellulose samples, with the exception of corncob cellulose, that exhibited the greatest extraction yield (26%) and morphological similarities to wood-derived microcrystalline cellulose, visible through SEM. Furthermore, corncob cellulose was found to have thermal properties (TOnset of 307.17 °C, TD of 330.31 °C, and ΔH of 306.04 kJ/kg) suitable for biomedical applications.
Occurrence of Escherichia coli non-susceptible to quinolones in faecal samples from fluoroquinolone-treated, contact and control pigs of different ages from 24 Swiss pig farms
Authors: Amsler Morena , Zurfluh Katrin , Hartnack Sonja , Sidler Xaver , Stephan Roger , Kümmerlen Dolf
Published: April 2021

Background

Despite their indispensability in human medicine, fluoroquinolones (FQ) are used for the treatment of bacterial infections in farm animals which increases the risk of transferring FQ-resistant bacteria into the environment and via the food chain to humans. The objectives of this observational study were to follow-up of the presence of quinolone non-susceptible Escherichia coli (QNSE) qualitatively and quantitatively in faecal samples of pigs at four time points (2 weeks old, 4 weeks old, 2 weeks post weaning and during fattening period). Moreover differences between groups of FQ-treated pigs, pigs with contact to treated pigs and control pigs were investigated. Additionally, quinolone and FQ resistance of Escherichia coli isolates of the faecal samples were investigated by determining minimum inhibitory concentrations (MICs).

Results

40.9% of 621 fecal samples contained QNSE. Proportion of samples with detectable QNSE from treated and contact pigs did not differ significantly and were highest in piglets of 2 and 4 weeks of age. However, the proportions of samples with QNSE were significantly lowest in control pigs (7/90; 7.8%; CI = 3.5–14.7%) among all groups. Also, the number of colony-forming units was lowest in both weaners and fattening pigs of the control group compared to treated and contact groups. Following CLSI human breakpoints, in total, 50.4% out of 254 isolates in faecal samples were intermediate or resistant to ciprofloxacin.

Conclusions

QNSE were present in faeces of pigs independent of age or FQ background but significantly less were found in pigs from farms without FQ usage. Due to the long half-life of FQ, it is likely that only a prolonged absence of fluoroquinolone treatments in pig farming will lead to a reduced frequency of QNSE in the farm environment. Solutions need to be found to minimise the emergence and transfer of quinolone and FQ-resistant bacteria from treated pigs to contact pigs and to farms without FQ usage.
Single and multi-area multi-fuel economic dispatch using a fuzzified squirrel search algorithm
Authors: Sakthivel V. Ponnuvel , Sathya P. Duraisamy
Published: April 2021

Multi-Area Multi-Fuel Economic Dispatch (MAMFED) aims to allocate the best generation schedule in each area and to offer the best power transfers between different areas by minimizing the objective functions among the available fuel alternatives for each unit while satisfying various constraints in power systems. In this paper, a Fuzzified Squirrel Search Algorithm (FSSA) algorithm is proposed to solve the single-area multi-fuel economic dispatch (SAMFED) and MAMFED problems. Squirrel Search Algorithm (SSA) mimics the foraging behavior of squirrels based on the dynamic jumping and gliding strategies. In the SSA approach, predator presence behavior and a seasonal monitoring condition are employed to increase the search ability of the algorithm, and to balance the exploitation and exploration. The suggested approach considers the line losses, valve point loading impacts, multi-fuel alternatives, and tie-line limits of the power system. Because of the contradicting nature of fuel cost and pollutant emission objectives, weighted sum approach and price penalty factor are used to transfer the bi-objective function into a single objective function. Furthermore, a fuzzy decision strategy is introduced to find one of the Pareto optimal fronts as the best compromised solution. The feasibility of the FSSA is tested on a three-area test system for both the SAMFED and MAMFED problems. The results of FSSA approach are compared with other heuristic approaches in the literature. Multi-objective performance indicators such as generational distance, spacing metric and ratio of non-dominated individuals are evaluated to validate the effectiveness of FSSA. The results divulge that the FSSA is a promising approach to solve the SAMFED and MAMFED problems while providing a better compromise solution in comparison with other heuristic approaches.
An expanded class of histidine-accepting viral tRNA-like structures
Authors: Langeberg Conner J. , Sherlock Madeline E. , MacFadden Andrea , Kieft Jeffrey S.
Published: April 2021

Structured RNA elements are common in the genomes of RNA viruses, often playing critical roles during viral infection. Some viral RNA elements use forms of tRNA mimicry, but the diverse ways this mimicry can be achieved are poorly understood. Histidine-accepting tRNA-like structures (TLSHis) are examples found at the 3′ termini of some positive-sense single-stranded RNA (+ssRNA) viruses where they interact with several host proteins, induce histidylation of the RNA genome, and facilitate processes important for infection, to include genome replication. As only five TLSHis examples had been reported, we explored the possible larger phylogenetic distribution and diversity of this TLS class using bioinformatic approaches. We identified many new examples of TLSHis, yielding a rigorous consensus sequence and secondary structure model that we validated by chemical probing of representative TLSHis RNAs. We confirmed new examples as authentic TLSHis by demonstrating their ability to be histidylated in vitro, then used mutational analyses to imply a tertiary interaction that is likely analogous to the D- and T-loop interaction found in canonical tRNAs. These results expand our understanding of how diverse RNA sequences achieve tRNA-like structure and function in the context of viral RNA genomes and lay the groundwork for high-resolution structural studies of tRNA mimicry by histidine-accepting TLSs.
Mining Bilateral Reviews for Online Transaction Prediction: A Relational Topic Modeling Approach
Authors: Chen Jiawei , Yang Yinghui (Catherine) , Liu Hongyan
Published: April 2021

In recent years, more and more platforms where both buyers and sellers can write reviews for each other have emerged. These bilateral reviews are important information sources in the decision-making process of both buyers and sellers. In this study, we develop a comprehensive relational topic modeling approach to analyze bilateral reviews for better online transaction prediction. The prediction results will enable the platform to increase the chance that the buyer and seller reach a transaction by presenting buyers with offerings that are more likely to lead to a transaction. Within the framework of the relational topic model, we embed a topic structure with both shared and corpus-specific topics to better handle text corpora generated from different sources. Our model facilitates the extraction of the appropriate topic structure from different document collections that helps enhance the transaction prediction performance. Comprehensive experiments conducted on real-world data sets collected from sharing economy platforms demonstrate that our new model significantly outperforms other alternatives. The robust results obtained from multiple sets of comparisons demonstrate the value of bilateral reviews if they are processed properly. Our approach can be applied to many platforms where bilateral reviews are available.
Breast cancer-related upper limb lymphoedema: an overview
Authors: Thomas Melanie
Published: April 2021

Breast cancer-related lymphoedema can be commonly encountered within a community nurse's role. The severity of lymphoedema can range considerably, from those who are considered ‘at risk’ due to breast cancer treatment, to individuals with highly complex oedema from advanced disease. This article provides an overview of breast cancer-related lymphoedema, including the risk factors for developing lymphoedema and the impact lymphoedema has physically, psychologically and socially. The treatments for lymphoedema, including clinical practical advice and skills, are presented to support ongoing personal development. A collaborative approach between community nurses and lymphoedema clinics is recommended to ensure that patients receive the best care possible.
Part 1: exploring views from fathers and perinatal practitioners on the inclusion of fathers by perinatal services
Authors: Fenton SK , Joscelyne T , Higgins S
Published: April 2021

Background

This is the first of a two-part series exploring father's inclusion in the perinatal years. Part 2 will explore the results of the study and discuss in relation to previous literature and to professional practice. Positive father involvement during the perinatal period has important implications for families. However, previous research suggests that fathers experience marginalisation, while staff report a lack of training and time for engaging fathers.

Aims

This study explored fathers' and perinatal professionals' experiences of fathers' involvement during the perinatal period, and ideas for paternal support.

Method

A Delphi method was employed. Thematic analysis from focus groups informed an online survey which was completed by 24 fathers and 22 professionals. A third-round survey finalised group consensus.

Results

Both groups agreed on the importance of fathers. Participants suggested improvement ideas, such as supporting fathers with psychological change. Groups disagreed on some ideas, such as fathers receiving a session alone to discuss concerns.

Discussion

The findings support the inclusion of fathers in perinatal services, and a focus on the whole family system. Limitations of this study include low participant diversity and possible selection bias. Implications for further research are discussed.
Part 1: COVID-19 and knowledge for midwifery practice—impact and care of pregnant women
Authors: Green Janet , Jones Linda , Petty Julia , Bromley Patricia , Fowler Cathrine , Walker Karen
Published: April 2021

The emergence of viral diseases, such as COVID-19, represents a global public health threat, particularly the high-impact animal viruses that have switched hosts and are able to be transmitted within human populations. Pandemics threaten the general population; however, there are special groups, such as pregnant women and their babies, which may be at a higher risk of, or more severely affected by infection. Pregnancy is considered a unique immunological condition; therefore, current challenges include decisions on preventing and treating infections during pregnancy and the possible implications for the fetus and newborn infant. This integrative review, the first of a two-part series, analyses selected literature on COVID-19 within maternal and newborn care, drawing on key themes relating to the impact on the pregnant woman. The themes discussed are: the nature of the immune system in pregnant and newly birthed mothers, maternal risk, mode and timing of birth, care during pregnancy and childbirth, and the transition to parenthood including the implications for practice for maternal mental wellbeing.
Widening inequalities should galvanise action across systems
Authors: Delap Naomi
Published: April 2021

Naomi Delap, Director of Birth Companions, reflects on the inequalities highlighted by the latest reports from MBRRACE-UK
Conversations of opportunity in diabetes care
Authors: Phillips Anne
Published: April 2021

Anne Phillips explores the ways in which diabetes consultations can be maximised to deliver the best effects for people living with diabetes and health professionals involved in their care

Changes to diabetes care due to the COVID-19 pandemic have caused extra pressures for both people living with diabetes and the health professionals involved in their care. Virtual and remote consulting has caused many health professionals to experience stress and usual face-to-face conversations with people living with diabetes have changed in context, frequency and delivery. The nuances of non-verbal communication can be lost in virtual consultations, so it is vitally important that health professionals are aware of this and consider how to deliver consultation conversations to the best effect. It is imperative that every contact counts and every virtual and face-to-face consultation has meaning for the person living with diabetes to maximise the benefit for the individual and their circumstances.
RESEARCH ROUNDUP
Authors: Winter George
Published: April 2021

George Winter provides an overview of recently published articles that are of interest to practice nurses. Should you wish to look at any of the papers in more detail, a full reference is provided.
Neither operative nor nonoperative approach is superior for treating displaced midshaft clavicle fractures: a partially blinded randomized controlled clinical trial
Authors: Ban Ilija , Kristensen Morten Tange , Barfod Kristoffer Weisskirchner , Eschen Jacob , Kallemose Thomas , Troelsen Anders
Published: April 2021

Aims

To compare the functionality of adults with displaced mid-shaft clavicular fractures treated either operatively or nonoperatively and to compare the relative risk of nonunion and reoperation between the two groups.

Methods

Based on specific eligibility criteria, 120 adults (median age 37.5 years (interquartile range (18 to 61)) and 84% males (n = 101)) diagnosed with an acute displaced mid-shaft fracture were recruited, and randomized to either the operative (n = 60) or nonoperative (n = 60) treatment group. This randomized controlled, partially blinded trial followed patients for 12 months following initial treatment. Functionality was assessed by the Constant score (CS) (assessor blinded to treatment) and Disability of the Arm, Shoulder and Hand (DASH) score. Clinical and radiological evaluation, and review of patient files for complications and reoperations, were added as secondary outcomes.

Results

At 12 months, 87.5% of patients (n = 105) were available for analysis. The two groups were well balanced based on demographic and fracture-related characteristics. At six weeks of follow-up a significant difference in DASH score (p < 0.001) was found in favour of operative treatment. The functionality at 12 months of follow-up based on CS and DASH was excellent in both groups (CS > 90 points and DASH < 10 points) with no significant difference (p = 0.277 for DASH and p = 0.184 for CS) between the two groups. The risk of symptomatic nonunion was significantly higher in the nonoperative group (p = 0.014), with a relative risk of 9.47 (95% confidence interval (CI) 1.26 to 71.53) in this group compared to the operative group. The number-needed-to-treat to avoid one symptomatic nonunion was 6.2. Initial treatment and age were factors significantly associated with nonunion in a logistic analysis. There were 26% in both groups (n = 14 in operative group and n = 15 in nonoperative group) who required secondary surgery, with most indications in the nonoperative group mandatory due to nonunion compared to most relative indications in the operative group requiring intervention due to implant irritation.

Conclusion

Superiority was not identified with either an all-operative or all-nonoperative approach. The functionality at short term (within six weeks) seems igreater following operative treatment but was not found at one year. The risk of nonunion is significantly higher with nonoperative treatment. However, an all-operative approach to lower the nonunion risk may result in unnecessary surgery and is not recommended. Cite this article: Bone Joint J 2021;103-B(4):762–768.
Efficient calibration method of total polarimetric errors in a channeled spectropolarimeter
Authors: Zhou Guodong , Li Yanqiu , Liu Ke
Published: April 2021

An efficient calibration method of total polarimetric errors in a channeled spectropolarimeter (CSP) is proposed and experimentally demonstrated. Total polarimetric errors, including alignment and retardance errors as well as those caused by nonideal retarders and the polarizer in CSP, are considered and calibrated. We first construct the calibrated modulation matrix of CSP by directly measuring the Mueller matrix spectrum of the polarization module in CSP. Compared to previously reported calibration works that required 1074 measurements, our calibration requires only 16 individual measurements, which reduces the measurement time by 67-fold while ensuring high accuracy with a maximum rms error less than 0.02. Further experimental test on three types of different CSP systems confirms the efficiency, reliability, and accuracy of the proposed calibration method.
Imaging striae distensae: a comparison between PS-OCT and digital dermoscopy
Authors: Lin Wai Ching , Byers Robert A. , Li Wei , Danby Simon G. , Cork Michael J. , Matcher Stephen J.
Published: April 2021

Stretch marks or striae distensae (SD) cause emotional distress and negatively affect the psychological well-being of patients. We investigate and compare two methods for quantifying the severity of SD: visual scoring of images captured using a clinical visible-light dermatological camera (C-Cube, Pixience Inc) and measuring the local birefringence of skin using polarization-sensitive optical coherence tomography (PS-OCT). Data on skin visually affected by SD and visually normal skin were collected from 19 human volunteers. Our results show a weak correlation between visual scores of the C-Cube images and the birefringence values obtained from the PS-OCT system. SD datasets have a significantly larger birefringence values compared to visually normal datasets.
Automatic detection of retinopathy with optical coherence tomography images via a semi-supervised deep learning method
Authors: Luo Yuemei , Xu Qing , Jin Ruibing , Wu Min , Liu Linbo
Published: April 2021

Automatic detection of retinopathy via computer vision techniques is of
great importance for clinical applications. However, traditional deep
learning based methods in computer vision require a large amount of
labeled data, which are expensive and may not be available in clinical
applications. To mitigate this issue, in this paper, we propose a
semi-supervised deep learning method built upon pre-trained VGG-16 and
virtual adversarial training (VAT) for the detection of retinopathy
with optical coherence tomography (OCT) images. It only requires very
few labeled and a number of unlabeled OCT images for model training.
In experiments, we have evaluated the proposed method on two popular
datasets. With only 80 labeled OCT images, the proposed method can
achieve classification accuracies of 0.942 and 0.936, sensitivities of
0.942 and 0.936, specificities of 0.971 and 0.979, and AUCs (Area
under the ROC Curves) of 0.997 and 0.993 on the two datasets,
respectively. When comparing with human experts, it achieves expert
level with 80 labeled OCT images and outperforms four out of six
experts with 200 labeled OCT images. Furthermore, we also adopt the
Gradient Class Activation Map (Grad-CAM) method to visualize the key
regions that the proposed method focuses on when making predictions.
It shows that the proposed method can accurately recognize the key
patterns of the input OCT images when predicting retinopathy.
Simulations of single- and two-tone Tm-doped optical fiber laser amplifiers
Authors: Goswami T. , Grosek J. , Gopalakrishnan J.
Published: April 2021

This work uses numerical simulations of a thulium-doped optical fiber amplifier to predict various performance characteristics such as peak temperatures, expected output powers and efficiencies, presence of amplified spontaneous emission (ASE), and transverse mode instability (TMI) onset power thresholds. Single- and two-tone configurations are studied. In the latter case, the two laser sources are separated in frequency by the amount that corresponds to the peak Raman gain, and a few seed ratios at various total seed powers are examined. The goal is to provide the field with pertinent information on what is feasible for this type of amplifier.
Random forest assisted vector displacement sensor based on a multicore fiber
Authors: Cui Jingxian , Luo Huaijian , Lu Jianing , Cheng Xin , Tam Hwa-Yaw
Published: April 2021

We proposed a two-dimensional vector displacement sensor with the capability of distinguishing the direction and amplitude of the displacement simultaneously, with improved performance assisted by random forest, a powerful machine learning algorithm. The sensor was designed based on a seven-core multi-core fiber inscribed with Bragg gratings, with a displacement direction range of 0-360° and the amplitude range related to the length of the sensor body. The displacement information was obtained under a random circumstance, where the performances with theoretical model and random forest model were studied. With the theoretical model, the sensor performed well over a shorter linear range (from 0 to 9 mm). Whereas the sensor assisted with random forest algorithm exhibits better performance in two aspects, a wider measurement range (from 0 to 45 mm) and a reduced measurement error of displacement. Mean absolute errors of direction and amplitude reconstruction were decreased by 60% and 98%, respectively. The proposed displacement sensor shows the possibility of machine learning methods to be applied in point-based optical systems for multi-parameter sensing.
Circularly polarized light emission from a GaN micro-LED integrated with functional metasurfaces for 3D display
Authors: Gao Xiang , Xu Yi , Huang Jinpeng , Hu Zelin , Zhu Wenhui , Yi Xiaoyan , Wang Liancheng
Published: April 2021

This Letter proposes a circularly polarized (CP) light GaN micro-LED which is integrated with functional metasurfaces. The one-dimensional metallic nanograting can achieve a high transverse electric (TE) reflectivity (

R

T
E

) and extinction ratio (ER) of TE and transverse magnetic (TM) waves, which is highly polarized output for micro-LEDs. Besides, the nanograting, which is integrated on the bottom of the GaN layer, can also support a resonant cavity, together with the top distributed Bragg reflector, which can shape the radiation pattern. By optimizing the structure parameters of nanograting, the

R

T
E

achieves over 80%, and the ER reaches higher than 38 dB at 450 nm for the GaN micro-LED. Additionally, the metasurface, which acts as a quarter-wave plate, was investigated to control the phase delay between the polarization state of the electric wave in two orthogonal components. Finally, the circular shape of the transmitted pattern denotes the high performance of the metasurface which is integrated in the micro-LED for CP light emission. The work reported in this Letter might provide potential application in a 3D polarized light display.
Simple quantum key distribution using a stable transmitter-receiver scheme
Authors: Ma Di , Liu Xin , Huang Chunfeng , Chen Huasheng , Lin Huanbin , Wei Kejin
Published: April 2021

Quantum key distribution (QKD) is a technology that allows secure key exchange between two distant users. A widespread adoption of QKD requires the development of simple, low-cost, and stable systems. However, implementation of the current QKD requires a complex self-alignment process during the initial stage and an additional hardware to compensate the environmental disturbances. In this study, we present the implementation of a simple QKD with the help of a stable transmitter-receiver scheme, which simplifies the self-alignment and is robust enough to withstand environmental disturbances. In case of the stability test, the implementation system is able to remain stable for 48 h and exhibits an average quantum bit error rate of less than 1% without any feedback control. The scheme is also tested over a fiber spool, obtaining a stable and secure finite key rate of 7.32k bits per second over a fiber spool extending up to 75 km. The demonstrated long-term stability and obtained secure key rate prove that our method of implementation is a promising alternative for practical QKD systems, in particular, for CubeSat platform and satellite applications.
Axial line-scanning stimulated emission depletion fluorescence correlation spectroscopy
Authors: Gao Peng , Nienhaus G. Ulrich
Published: April 2021

Investigating the dynamics and interactions of biomolecules within or attached to membranes of living cells is crucial for understanding biology at the molecular level. In this pursuit, classical, diffraction-limited optical fluorescence microscopy is widely used, but it faces limitations due to (1) the heterogeneity of biomembranes on the nanoscale and (2) the intrinsic motion of membranes with respect to the focus. Here we introduce a new confocal microscopy-based fluctuation spectroscopy technique aimed at alleviating these two problems, called axial line-scanning stimulated emission depletion fluorescence correlation spectroscopy (axial ls-STED-FCS). Axial line scanning by means of a tunable acoustic gradient index of refraction lens provides a time resolution of a few microseconds, which is more than two orders of magnitude greater than that of conventional, lateral line-scanning fluorescence correlation spectroscopy (typically around 1 ms). Using STED excitation, the observation area on the membrane can be reduced 10–100 fold, resulting in sub-diffraction spatial resolution and the ability to study samples with densely labeled membranes. Due to these attractive properties, we expect that the axial ls-STED-FCS will find wide application, especially in the biomolecular sciences.
Full wafer scale electroluminescence properties of AlGaN-based deep ultraviolet LEDs with different well widths
Authors: Zhang Yi , Zhang Shuang , Xu Linlin , Zhang Huixue , Wang Ange , Shan Maocheng , Zheng Zhihua , Wang Hao , Wu Feng , Dai Jiangnan , Chen Changqing
Published: April 2021

Deep ultraviolet (DUV) LEDs have great potential in sterilization, water, air purification, and other fields. In this work, DUV LED wafers with different quantum well (QW) widths were grown by metal–organic chemical vapor deposition. It is found that the light output power (LOP) and peak wavelength of all chips are not only related to the QW thickness but also affected by warpage. For the first time, to the best of our knowledge, a positive correlation between the LOP and peak wavelength of DUV LED chips on the same wafer was observed, which is very important for improving the yield of DUV LEDs and reducing costs. Furthermore, the influence of QW thickness on the external quantum efficiency (EQE) of DUV LED has also been investigated. As the thickness of the QW increases, the exciton localization effect decreases and the quantum confinement Stark effect increases. Consequently, DUV LED wafers with a QW thickness of 2 nm have the highest EQE and yield. These findings not only help to improve the efficiency of DUV LEDs but also provide new insights for evaluating the performance of DUV LED wafers.
AlSb as a material for high index contrast nanophotonics
Authors: Bauser Haley C. , Needell David R. , Atwater Harry A.
Published: April 2021

High contrast materials, i.e., materials with a high refractive index and low optical loss, are of wide interest for nanophotonics and metasurface designs at optical and near infrared wavelengths. We explore aluminum antimonide (AlSb) as a high contrast nanophotonic material, using the design of high contrast gratings (HCGs) for low loss dielectric mirrors as an example. The high index of refraction and low absorption coefficient of AlSb in the visible wavelength range enable designs of HCGs that can be effectively optimized to form mirrors with 93.5% reflectivity at red visible wavelengths. We detail a co-sputtering synthesis method for AlSb films, and achieve our target high index of refraction of 3.5 for 635 nm light. We also find that the high sensitivity of AlSb oxidation requires specific handling procedures in developing deposition processes to yield a near zero absorption coefficient.
High-performance quantum-dot distributed feedback laser on silicon for high-speed modulations
Authors: Liang Di , Srinivasan Sudharsanan , Descos Antoine , Zhang Chong , Kurczveil Geza , Huang Zhihong , Beausoleil Raymond
Published: April 2021

We report a 1310 nm heterogeneous quantum-dot distributed feedback laser on silicon with high efficiency and modulation capability and demonstrate isolator-free external modulation at 25 Gb/s using a metal-oxide semiconductor capacitor microring modulator.
Multiplexing scheme for digital signal processing-assisted coherent radio over fiber system
Authors: Chen Guang , Ma Jianxin , Wang Kuiru , Yuan Jinhui , Zhou Xian , Qu Yuwei , Yan Binbin , Sang Xinzhu , Yu Chongxiu
Published: April 2021

In this paper, a multiplexing scheme, involving optical tandem single-sideband modulation, orthogonal optical single-sideband multiplexing, and digital signal processing (DSP)-assisted optical coherent detection, is proposed. Based on the design, a coherent radio-over-fiber (RoF) optical transmission system is established, which improves channel capacity and spectrum efficiency. Phase-modulated radio frequency signals with different bit rates are carried on an optical single-carrier, transmitted, received after 40 km transmission, and recovered by the DSP algorithm. System performances for all binary phase-shift keying channels are verified by simulation and experiment. Thus, the proposed multiplexing scheme is feasible to improve channel capacity and spectrum efficiency without increasing the system complexity. The work in this paper brings potential applications to coherent RoF systems and hybrid optical wireless communications for future broadband wireless access networks.
Integrating the optical tweezers and spanner onto an individual single-layer metasurface
Authors: Li Tianyue , Xu Xiaohao , Fu Boyan , Wang Shuming , Li Baojun , Wang Zhenlin , Zhu Shining
Published: April 2021

Optical tweezers (OTs) and optical spanners (OSs) are powerful tools of optical manipulation, which are responsible for particle trapping and rotation, respectively. Conventionally, the OT and OS are built using bulky three-dimensional devices, such as microscope objectives and spatial light modulators. Recently, metasurfaces are proposed for setting up them on a microscale platform, which greatly miniaturizes the systems. However, the realization of both OT and OS with one identical metasurface is posing a challenge. Here, we offer a metasurface-based solution to integrate the OT and OS. Using the prevailing approach based on geometric and dynamic phases, we show that it is possible to construct an output field, which promises a high-numerical-aperture focal spot, accompanied with a coaxial vortex. Optical trapping and rotation are numerically demonstrated by estimating the mechanical effects on a particle probe. Moreover, we demonstrate an on-demand control of the OT-to-OS distance and the topological charge possessed by the OS. By revealing the OT–OS metasurfaces, our results may empower advanced applications in on-chip particle manipulation.
Next-generation yeast-two-hybrid analysis with Y2H-SCORES identifies novel interactors of the MLA immune receptor
Authors: Velásquez-Zapata Valeria , Elmore J. Mitch , Banerjee Sagnik , Dorman Karin S. , Wise Roger P.
Published: April 2021

Protein-protein interaction networks are one of the most effective representations of cellular behavior. In order to build these models, high-throughput techniques are required. Next-generation interaction screening (NGIS) protocols that combine yeast two-hybrid (Y2H) with deep sequencing are promising approaches to generate interactome networks in any organism. However, challenges remain to mining reliable information from these screens and thus, limit its broader implementation. Here, we present a computational framework, designated Y2H-SCORES, for analyzing high-throughput Y2H screens. Y2H-SCORES considers key aspects of NGIS experimental design and important characteristics of the resulting data that distinguish it from RNA-seq expression datasets. Three quantitative ranking scores were implemented to identify interacting partners, comprising:1)significant enrichment under selection for positive interactions,2)degree of interaction specificity among multi-bait comparisons, and3)selection ofin-frameinteractors. Using simulation and an empirical dataset, we provide a quantitative assessment to predict interacting partners under a wide range of experimental scenarios, facilitating independent confirmation by one-to-one bait-prey tests. Simulation of Y2H-NGIS enabled us to identify conditions that maximize detection of true interactors, which can be achieved with protocols such as prey library normalization, maintenance of larger culture volumes and replication of experimental treatments. Y2H-SCORES can be implemented in different yeast-based interaction screenings, with an equivalent or superior performance than existing methods. Proof-of-concept was demonstrated by discovery and validation of novel interactions between the barley nucleotide-binding leucine-rich repeat (NLR) immune receptor MLA6, and fourteen proteins, including those that function in signaling, transcriptional regulation, and intracellular trafficking.
Computation of the electroencephalogram (EEG) from network models of point neurons
Authors: Martínez-Cañada Pablo , Ness Torbjørn V. , Einevoll Gaute T. , Fellin Tommaso , Panzeri Stefano
Published: April 2021

The electroencephalogram (EEG) is a major tool for non-invasively studying brain function and dysfunction. Comparing experimentally recorded EEGs with neural network models is important to better interpret EEGs in terms of neural mechanisms. Most current neural network models use networks of simple point neurons. They capture important properties of cortical dynamics, and are numerically or analytically tractable. However, point neurons cannot generate an EEG, as EEG generation requires spatially separated transmembrane currents. Here, we explored how to compute an accurate approximation of a rodent’s EEG with quantities defined in point-neuron network models. We constructed different approximations (or proxies) of the EEG signal that can be computed from networks of leaky integrate-and-fire (LIF) point neurons, such as firing rates, membrane potentials, and combinations of synaptic currents. We then evaluated how well each proxy reconstructed a ground-truth EEG obtained when the synaptic currents of the LIF model network were fed into a three-dimensional network model of multicompartmental neurons with realistic morphologies. Proxies based on linear combinations of AMPA and GABA currents performed better than proxies based on firing rates or membrane potentials. A new class of proxies, based on an optimized linear combination of time-shifted AMPA and GABA currents, provided the most accurate estimate of the EEG over a wide range of network states. The new linear proxies explained 85–95% of the variance of the ground-truth EEG for a wide range of network configurations including different cell morphologies, distributions of presynaptic inputs, positions of the recording electrode, and spatial extensions of the network. Non-linear EEG proxies using a convolutional neural network (CNN) on synaptic currents increased proxy performance by a further 2–8%. Our proxies can be used to easily calculate a biologically realistic EEG signal directly from point-neuron simulations thus facilitating a quantitative comparison between computational models and experimental EEG recordings.
Novel Variance-Component TWAS method for studying complex human diseases with applications to Alzheimer’s dementia
Authors: Tang Shizhen , Buchman Aron S. , De Jager Philip L. , Bennett David A. , Epstein Michael P. , Yang Jingjing
Published: April 2021

Transcriptome-wide association studies (TWAS) have been widely used to integrate transcriptomic and genetic data to study complex human diseases. Within a test dataset lacking transcriptomic data, traditional two-stage TWAS methods first impute gene expression by creating a weighted sum that aggregates SNPs with their corresponding cis-eQTL effects on reference transcriptome. Traditional TWAS methods then employ a linear regression model to assess the association between imputed gene expression and test phenotype, thereby assuming the effect of a cis-eQTL SNP on test phenotype is a linear function of the eQTL’s estimated effect on reference transcriptome. To increase TWAS robustness to this assumption, we propose a novel Variance-Component TWAS procedure (VC-TWAS) that assumes the effects of cis-eQTL SNPs on phenotype are random (with variance proportional to corresponding reference cis-eQTL effects) rather than fixed. VC-TWAS is applicable to both continuous and dichotomous phenotypes, as well as individual-level and summary-level GWAS data. Using simulated data, we show VC-TWAS is more powerful than traditional TWAS methods based on a two-stage Burden test, especially when eQTL genetic effects on test phenotype are no longer a linear function of their eQTL genetic effects on reference transcriptome. We further applied VC-TWAS to both individual-level (N = ~3.4K) and summary-level (N = ~54K) GWAS data to study Alzheimer’s dementia (AD). With the individual-level data, we detected 13 significant risk genes including 6 known GWAS risk genes such as TOMM40 that were missed by traditional TWAS methods. With the summary-level data, we detected 57 significant risk genes considering only cis-SNPs and 71 significant genes considering both cis- and trans- SNPs, which also validated our findings with the individual-level GWAS data. Our VC-TWAS method is implemented in the TIGAR tool for public use.