bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors related to excessive out-of-pocket expenditures among the ultra-poor after discontinuity of PBF: a cross-sectional study in Burkina Faso
Authors: Beaugé Yvonne , Ridde Valéry , Bonnet Emmanuel , Souleymane Sidibé , Kuunibe Naasegnibe , De Allegri Manuela
Published: November 2020

Background

Measuring progress towards financial risk protection for the poorest is essential within the framework of Universal Health Coverage. The study assessed the level of out-of-pocket expenditure and factors associated with excessive out-of-pocket expenditure among the ultra-poor who had been targeted and exempted within the context of the performance-based financing intervention in Burkina Faso. Ultra-poor were selected based on a community-based approach and provided with an exemption card allowing them to access healthcare services free of charge.

Methods

We performed a descriptive analysis of the level of out-of-pocket expenditure on formal healthcare services using data from a cross-sectional study conducted in Diébougou district. Multivariate logistic regression was performed to investigate the factors related to excessive out-of-pocket expenditure among the ultra-poor. The analysis was restricted to individuals who reported formal health service utilisation for an illness-episode within the last six months. Excessive spending was defined as having expenditure greater than or equal to two times the median out-of-pocket expenditure.

Results

Exemption card ownership was reported by 83.64% of the respondents. With an average of FCFA 23051.62 (USD 39.18), the ultra-poor had to supplement a significant amount of out-of-pocket expenditure to receive formal healthcare services at public health facilities which were supposed to be free. The probability of incurring excessive out-of-pocket expenditure was negatively associated with being female (β = − 2.072,p = 0.00, ME = − 0.324;p = 0.000) and having an exemption card (β = − 1.787,p = 0.025; ME = − 0.279,p = 0.014).

Conclusions

User fee exemptions are associated with reduced out-of-pocket expenditure for the ultra-poor. Our results demonstrate the importance of free care and better implementation of existing exemption policies. The ultra-poor’s elevated risk due to multi-morbidities and severity of illness need to be considered when allocating resources to better address existing inequalities and improve financial risk protection.
Preoperative prognostic factors associated with postoperative delirium in older people undergoing surgery: protocol for a systematic review and individual patient data meta-analysis
Authors: Buchan Tayler A. , Sadeghirad Behnam , Schmutz Nayeli , Goettel Nicolai , Foroutan Farid , Couban Rachel , Mbuagbaw Lawrence , Dodsworth Benjamin T.
Published: November 2020

Background

Early identification of patients at risk for postoperative delirium is essential because adequate well-timed interventions could reduce the occurrence of delirium and the related detrimental outcomes.

Methods

We will conduct a systematic review and individual patient data (IPD) meta-analysis of prognostic studies evaluating the predictive value of risk factors associated with an increased risk of postoperative delirium in elderly patients undergoing elective surgery. We will identify eligible studies through systematic search of MEDLINE, EMBASE, and CINAHL from their inception to May 2020. Eligible studies will enroll older adults (≥ 50 years) undergoing elective surgery and assess pre-operative prognostic risk factors for delirium and incidence of delirium measured by a trained individual using a validated delirium assessment tool. Pairs of reviewers will, independently and in duplicate, screen titles and abstracts of identified citations, review the full texts of potentially eligible studies. We will contact chief investigators of eligible studies requesting to share the IPD to a secured repository. We will use one-stage approach for IPD meta-analysis and will assess certainty of evidence using the GRADE approach.

Discussion

Since we are using existing anonymized data, ethical approval is not required for this study. Our results can be used to guide clinical decisions about the most efficient way to prevent postoperative delirium in elderly patients.

Systematic review registration

CRD42020171366.
Identifying VOCs in exhibition cases and efflorescence on museum objects exhibited at Smithsonian’s National Museum of the American Indian-New York
Authors: Alvarez-Martin Alba , George John , Kaplan Emily , Osmond Lauren , Bright Leah , Newsome G. Asher , Kaczkowski Rebecca , Vanmeert Frederik , Kavich Gwénaëlle , Heald Susan
Published: November 2020

Two mass spectrometry (MS) methods, solid-phase microextraction gas chromatography (SPME–GC–MS) and direct analysis in real time (DART-MS), have been explored to investigate widespread efflorescence observed on exhibited objects at the Smithsonian’s National Museum of the American Indian in New York (NMAI-NY). Both methods show great potential, in terms of speed of analysis and level of information, for identifying the organic component of the efflorescence as 2,2,6,6-tetramethyl-4-piperidinol (TMP-ol) emitted by the structural adhesive (Terostat MS 937) used for exhibit case construction. The utility of DART-MS was proven by detecting the presence of TMP-ol in construction materials in a fraction of the time and effort required for SPME–GC–MS analysis. In parallel, an unobtrusive SPME sampling strategy was used to detect volatile organic compounds (VOCs) accumulated in the exhibition cases. This sampling technique can be performed by collections and conservation staff at the museum and shipped to an off-site laboratory for analysis. This broadens the accessibility of MS techniques to museums without access to instrumentation or in-house analysis capabilities.
Parallel transjugular intrahepatic portosystemic shunt (TIPS) for TIPS dysfunction: technical and patency outcome
Authors: Alwarraky Mohamed S. , Elzohary Hasan A. , Melegy Mohamed A. , Mohamed Anwar
Published: November 2020

Background

Several methods have been used in treating TIPS dysfunction, including balloon angioplasty with/without telescoping stent. However, there are some cases refractory to recanalization and parallel shunt (PS) should be tried. The aim is to evaluate the technical and patency outcomes of the PS. We retrospectively reviewed the medical records of patients (n = 37) with refractory TIPS dysfunction who were managed by PS. All clinical, laboratory, and technical data as well as radiological data over 1 year were collected. Technical success was the primary outcome while complications and shunt patency were the secondary outcomes.

Results

Thirty-three out of the 37 patients (89.2%) of the study were Budd-Chiari syndrome cases. Caval puncture was done in 34/37 (91.9%) of cases while the hepatic vein puncture was done in 3/37 cases (8.1%). Portal entry through the left branch was done in 22 patients (59.5%), from neck of PV in 13 patients (35.1%) to right PV in 2 patients (5.4%). Technical success was achieved in 100% of cases. Porto-systemic pressure gradient (PSG) before PS insertion was 32.5 ± 8.1 mmHg and it became 8.9 ± 2.3 mmHg after the PS insertion (P < 0.01). The median primary patency duration was 11 months. The estimated 12 and 18 months primary patency rates were 32/37 (86.5%) and (78.4%) respectively. Intra-procedure complications occurred in 8 patients (21.6%) and were successfully treated medically. Acute PS thromboses occurred in 4 patients (10.8%) and required early successful interventions.

Conclusion

It is proven from this study that patients with refractory TIPS occlusion have another chance for a second PS to treat portal hypertension symptoms. Moreover, the PS is a durable, safe, and effective treatment on mid-term basis.
Development and evaluation of mucoadhesive bigel containing tenofovir and maraviroc for HIV prophylaxis
Authors: Ilomuanya Margaret O. , Hameedat Ayotunde T. , Akang Edidiong N , Ekama Sabdat O. , Silva Boladale O. , Akanmu Alani S
Published: November 2020

Background

Sexual transmission of HIV is the most common means of acquiring the disease. Topical microbicides have been investigated to prevent transmission. This study will use a specific entry inhibitor, maraviroc, and a nucleotide reverse transcriptase inhibitor (NRTI), tenofovir, a dual combination which will provide a synergist effect that can enhance the efficacy of HIV microbicides via a mucoadhesive dual compartment bigel. Bigel formulation via hydrogel organogel linkages were developed and evaluated for their physicochemical characteristics, safety, and anti-HIV efficacy. In vitro diffusion studies were performed with Franz diffusion cells having effective diffusion surface area of 1.76cm2 and receiver chamber volume of 15mL.

Result

The bigel formulations showed a viscosity ranging from 14179 to 14560 cPs and had a good spreadability and acidic pH in the range of 4.0 ± 0.34 to 5.2 ± 0.18. The bigel formulations showed good anti-HIV activity at a concentration of 0.1 μg/mL. The in vitro release study of maraviroc from the bigel formulations showed a release rate ranging from 2.675 to 3.838 μg/cm2/min½ while the release rate for tenofovir ranged from 3.475 to 3.825 μg/cm2/min½. The bigel formulations were non-toxic to the human vagina as there was < 1 log10 change in Lactobacilli crispatus viability.

Conclusion

This study successfully developed a dual compartment bigel containing maraviroc and tenofovir. BG C was found to be stable and safe towards vaginal and rectal epithelium, and it actively prevented HIV transmission. This bigel has the potential for long-term pre-exposure prophylaxis prevention of HIV transmission.
Psychological interventions as an alternative and add-on to antidepressant medication to prevent depressive relapse: systematic review and meta-analysis
Authors: Breedvelt Josefien Johanna Froukje , Brouwer Maria Elisabeth , Harrer Mathias , Semkovska Maria , Ebert David Daniel , Cuijpers Pim , Bockting Claudi Louisa Hermina
Published: November 2020

Background

After remission, antidepressants are often taken long term to prevent depressive relapse or recurrence. Whether psychological interventions can be a viable alternative or addition to antidepressants remains unclear.

Aims

To compare the effectiveness of psychological interventions as an alternative (including delivered when tapering antidepressants) or addition to antidepressants alone for preventing depressive relapse.

Method

Embase, PubMed, the Cochrane Library and PsycINFO were searched from inception until 13 October 2019. Randomised controlled trials (RCTs) with previously depressed patients in (partial) remission where preventive psychological interventions with or without antidepressants (including tapering) were compared with antidepressant control were included. Data were extracted independently from published trials. A random-effects meta-analysis on time to relapse (hazard ratio, HR) and risk of relapse (risk ratio, RR) at the last point of follow-up was conducted. PROSPERO ID: CRD42017055301.

Results

Among 11 included trials (n = 1559), we did not observe an increased risk of relapse for participants receiving a psychological intervention while tapering antidepressants versus antidepressants alone (RR = 1.02, 95% CI 0.84–1.25; P = 0.85). Psychological interventions added to antidepressants significantly reduced the risk of relapse (RR = 0.85, 95% CI 0.74–0.97; P = 0.01) compared with antidepressants alone.

Conclusions

This study found no evidence to suggest that adding a psychological intervention to tapering increases the risk of relapse when compared with antidepressants alone. Adding a psychological intervention to antidepressant use reduces relapse risk significantly versus antidepressants alone. As neither strategy is routinely implemented these findings are relevant for patients, clinicians and guideline developers.
Mammographic Screening in the Occupied Palestinian Territory: A Critical Analysis of Its Promotion, Claimed Benefits, and Safety in Palestinian Health Research
Authors: AlWaheidi Shaymaa , McPherson Klim , Chalmers Iain , Sullivan Richard , Davies Elizabeth A.
Published: November 2020

PURPOSE

To critically review the evidence and opinions expressed about mammographic screening (MS) in research reports on breast cancer in the occupied Palestinian territory (oPt) and to assess whether benefits and harms in MS are presented in a balanced way.

METHODS

Searches of PubMed, Cochrane, MEDLINE, EMBASE, CINAHL, and gray literature identified 14 eligible research reports relating to the oPt. We reviewed these documents and then used a thematic analysis to describe and analyze the evidence and the opinions about MS expressed in them.

RESULTS

All 14 research reports mentioned that MS would improve survival rates in the oPt. Only three gave information on major harmful effects, and only two emphasized that MS must be accompanied by effective treatment to have any beneficial effects on population mortality. There was no consistency in the recommended frequency of MS.

CONCLUSION

Most information presented by Palestinian health researchers was selective and failed to address the important established harms of MS. Thus, calls to support MS in the oPt are not based on a measured discussion of the risks and benefits for women or grounded in the systemic readiness of health care necessary for its effectiveness. As long as diagnostic and treatment facilities remain deficient, screening cannot lead to reduced mortality from breast cancer.
Sustained Breast Development and Breast Anthropometric Changes in 3 Years of Gender-Affirming Hormone Treatment
Authors: de Blok Christel J M , Dijkman Benthe A M , Wiepjes Chantal M , Staphorsius Annemieke S , Timmermans Floyd W , Smit Jan Maerten , Dreijerink Koen M A , den Heijer Martin
Published: November 2020

Context

Breast development is important for most trans women. An important limitation of current breast development measurement methods is that these do not allow for 3D volume analyses.

Objectives

To examine breast development and change in anthropometry during the first 3 years of gender-affirming hormone treatment using 3D imaging. Associations with clinical or laboratory parameters and satisfaction with the gained breast development were also studied.

Design

Prospective cohort study.

Setting

Specialized tertiary gender identity clinic in Amsterdam, the Netherlands.

Participants

Participants were 69 adult trans women with a median age of 26 years (interquartile range, 21-38).

Interventions

Gender-affirming hormone treatment.

Main Outcome Measures

Volumetric and anthropometric breast development and satisfaction.

Results

Breast volume increased by 72 cc (95% confidence interval [CI], 48-97) to 100 cc (standard deviation 48). This resulted in a cup-size <A-cup in 71% of the participants. Although the change in breast-chest difference plateaued after approximately 9 months, sustained increase in breast volume was observed during the 3-year observation period. Sternal notch to nipple distance increased by 1.3 cm (95% CI, 0.9-1.7) and internipple distance increased by 1.0 cm (95% CI, 0.4-1.5). At least 58% of trans women were satisfied with the gained breast size.

Conclusions

Sustained breast growth and development during hormone treatment was observed during the full 3-year observation period. The breasts of trans women are positioned more laterally and caudally on the chest compared with cis women. Although modest breast volumes were observed, breast development was satisfactory to most trans women.
Plasticity in perception: insights from color vision deficiencies
Authors: Isherwood Zoey J , Joyce Daniel S , Parthasarathy Mohana Kuppuswamy , Webster Michael A
Published: November 2020

Inherited color vision deficiencies typically result from a loss or alteration of the visual photopigments absorbing light and thus impact the very first step of seeing. There is growing interest in how subsequent steps in the visual pathway might be calibrated to compensate for the altered receptor signals, with the possibility that color coding and color percepts might be less severely impacted than the receptor differences predict. These compensatory adjustments provide important insights into general questions about sensory plasticity and the sensory and cognitive processes underlying how we experience color.
ACCESS TO LEADERSHIP EFFICACY: Those Who Start Early Finish Ahead
Authors: Haddad Becky , Pierszalowski Sophie , Velez Jonathan
Published: November 2020

An increasing number of studies point to student gains from participation in leadership development opportunities. However, very little research exists to explore who has access to these experiences. In this paper, we investigate whether a student’s employment off-campus has an impact on their ability to participate in, and experience gains in leadership efficacy from leadership training opportunities. We employ a linear regression path analysis to identify potential relationships between pre-college leadership efficacy, off-campus employment, participation in leadership training opportunities, and leadership efficacy for undergraduate students at a university in the Pacific Northwest. Pre-college leadership efficacy was the strongest predictor of leadership efficacy for undergraduate students, with hours of employment and leadership training having small, but significant, mediating effects. This begs the question: How do students build their leadership efficacy prior to entering post-secondary education and what drives students to continue to pursue experiences that develop their leadership efficacy?
IN TUNE WITH THE XEROPHYTE: Examining Leadership during an Original Music Production Process
Authors: Payne Adam
Published: November 2020

The process of making an original music album is highlighted to illustrate aspects of the music production process in addition to how leadership and related factors play out during this process. Background information is detailed regarding musicians as entrepreneurs, the music production process, group dynamics, learning approaches, aspects of group dynamics, and an emphasis on more shared, distributive forms of leadership. The conceptual framework and results of the ethnographic field study describe a music production process consisting of the following phases: Pre-Production; Production; and Post-Production, with decision-making, direction-setting, and overall leadership approaches playing out at each phase. Reflections, key learnings, and recommendations for future research are presented, all centering on the usefulness in identifying the process of original music production.
THE EVOLUTION OF INCLUSIVE LEADERSHIP STUDIES: A literature review
Authors: Thompson Herb , Matkin Gina
Published: November 2020

The dramatic increase of diversity on US college campuses has coincided with greater academic interest on the concept of inclusive leadership. The present literature provides a systematic analysis of literature from its forming phases in the early 1990s to its present condition. Priority publications were selected rigorously and then examined in order to better determine what theoretical emphasis each of the three decades might have yielded and which what these studies reveal about the evolution of this relatively new leadership paradigm. From the review themes were identified and observations were made for future research purposes.
THE INFLUENCE OF BEING A MENTOR ON LEADERSHIP DEVELOPMENT: Recommendations for Curricular and Co-Curricular Experiences
Authors: Lee Jim , Sunerman Hannah , Hastings Lindsay
Published: November 2020

While there are well-established personal benefits to being a mentor, such as increased life satisfaction and job performance (Ramaswami & Dreher, 2007), how mentors grow and develop requires exploration. We meet this need by presenting six key themes from two recent research studies related to the experiences that mentors perceived as contributing to their development. The growth of two leadership theories in particular were explored: generativity and Psychological Capital. Six themes emerged: (a) curricular training, (b) exposure to leadership outcomes, (c) being mentored by peers, (d) experiences with mentee, (e) reflection, and (f ) observing a ripple effect. These themes offer insights on how curricular and co-curricular experiences might maximize leadership development of students and ground leadership interventions, such as mentoring, in theory and research.
BUILDING LEADERSHIP SKILLS THROUGH HIGH-IMPACT EXPERIENCES
Authors: Andreu F. Scott , Sweet Kenneth M. , Carter Douglas H.
Published: November 2020

The Organizational Leadership class is a staple in most undergraduate and graduate management curricula. Faculty teaching leadership courses recognize the need for experiential learning, but often struggle to find meaningful and manageable learning opportunities. Based on the high-impact practices of service and community-based learning, we offer three high-impact experiences designed to complement an organizational leadership course. These experiences utilize experiential learning to reinforce the critical leadership skills of demonstrate empathy, professional networking, and lifelong self-development. These experiences, coupled with self-reflection, enable students to grow their leadership capability while building demonstrable professional skills.
ASSESSING INTERCULTURAL COMPETENCE IN INTERNATIONAL LEADERSHIP COURSES: Developing the Global Leader
Authors: Armstrong Josh P.
Published: November 2020

The leaders of the future will have to lead with intercultural competence and with the ability to facilitate this development of competence in others. The development of skills in undergraduate students to meet this challenge is paramount to the establishment of effective leadership for the future. Within this study, researchers address the challenge by quantitatively examining intercultural competency outcomes students derive from leadership-based study abroad experiences. For five years, researchers utilized a pre-post intercultural competency survey of student participants in a leadership education study abroad program in Zambia, Africa. Using the Intercultural Effectiveness Scale (IES), data was analyzed for seventy-eight students who participated in this five-week study abroad course. The results demonstrate statistically significant growth on students’ intercultural competency across all ten measures of dimensions and sub-scales. Recommendations provide a framework for leadership educators to employ pedagogies that influence intercultural development within study abroad as a means of developing global leadership in their students.
ECO-LEADERSHIP AMONG COUNTY 4-H ORGANIZATIONS: Relationship to Programmatic Success and Best Practices for Eco-Leaders
Authors: Cletzer D. Adam , Kaufman Eric K.
Published: November 2020

Our understanding of leaders and the role they play in organizations and society is changing, which has important implications for leadership education. At the turn of the century, society began to move from a mechanistic understanding of leadership to a more ecological one. The latter, ecological approach to leadership is characterized by collective decision-making, collaboration, shared leadership, and grassroots organization. While leadership educators have acknowledged this shift, more case examples are needed to illuminate practical implications for leadership. This study of county 4-H associations uses an explanatory sequential mixed methods design to explore the relationship between three factors: (a) subjects’ levels of hierarchical and systemic thinking; (b) how their associations engage in leadership and organizational learning; and (c) programmatic success. While no direct relationship emerged between programmatic success and subjects’ levels of hierarchical and systemic thinking, mixed methods results revealed several distinctions between high and low scoring programs’ approaches to leadership. These distinctions support an ecological approach to leadership, which in turn impacts modern approaches to leadership education.
WHAT THE BEST LEADERSHIP EDUCATORS DO: A Sequential Explanatory Mixed Methods Study of Instructional and Assessment Strategy Use in Leadership Education
Authors: Jenkins Daniel M.
Published: November 2020

The purpose of this mixed methods sequential explanatory study was to identify the best pedagogical practices of leadership educators by obtaining quantitative data from surveying 836 leadership educators about their instructional and assessment strategy choices and then following up with qualitative interviews of 13 leadership educators recommended as “exemplary” by their peers to explore those results in more depth. In the first, quantitative phase, discussion-based pedagogies, case studies, and group projects/presentations were found to be the most frequently used instructional and assessment strategies. In the qualitative follow up phase, rich data related to specific pedagogical groups and five themes related to participants’ pedagogical choices emerged. The quantitative and qualitative findings from the two phases are integrated and discussed with reference to prior research and implications and recommendations are provided
ENRICHING COLLEGE STUDENTS’ LEADERSHIP EFFICACY
Authors: Soria Krista M. , Kaste Karl , Diekemper Kelly M. , Blamo Milpha , Belrose Maddie R. , Brazelton G. Blue
Published: November 2020

The purpose of this study was to examine whether undergraduates’ participation in 12 different leadership trainings, workshops, conferences, or programs was associated with students’ leadership efficacy. We used data from the Multi-Institutional Study of Leadership survey, which eight of the Big 10 institutions administered to students in spring 2018. The results suggest that students’ participation in shorter-term or moderate-term experiences—a leadership conference, retreat, lecture/workshop series, course, or positional leadership training—was positively associated with students’ leadership efficacy. We therefore encourage leadership educators and practitioners in higher education to consider the duration of their programs to maximize students’ outcomes.
ELEVATING LEADERSHIP DEVELOPMENT PRACTICES TO MEET EMERGING NEEDS
Authors: Chesley Julie A. , Egan Terri , Jones Hannah E.
Published: November 2020

The changing landscape that leaders face demands an evolution of leadership development that not only builds skills but also grows a leader’s capacity to effectively respond to and manage an ambiguous, uncertain and changing future. Based on adult development theory, we explore the nuanced difference of leadership development through two distinct, but equally useful lenses: horizontal and vertical leadership development. We examined the state of leadership development practice across fifteen large organizations and present differences in how six common leadership development practices including assessments, individual development plans, expert knowledge sharing, mentorship, coaching, and experiential opportunities were used in a more traditional skill-building way, and how principles of vertical development were incorporated. We conclude with specific practical approaches to modify traditional practices to meet emerging needs.
Tracing a standard language in Austria using methodological microvariations of Verbal and Matched Guise Technique
Authors: Koppensteiner Wolfgang , Lenz Alexandra
Published: November 2020

Based on the key hypothesis, that there are heterogeneous conceptualizations of “standardness” within the German speaking countries, this paper both methodologically and empirically tangles main aspects on “standard in Austria” from the perspective of perceptual variationist linguistics. Two series of comprehensive listener judgment tests based on 536 informants, considering different sociolinguistic parameters and assumptions on model speakers, indicate shiftings away from competing (country-specific) conceptualizations towards heterogeneous dimensions of “standard in Austria” with complex evaluative patterns.
Erzählen als multimodale Aktivität – zur Einführung in das Themenheft
Authors: Zima Elisabeth , Weiß Clarissa
Published: November 2020

This special issue of Linguistik online is dedicated to the study of storytelling in face-to-face interaction. More specifically, the individual contributions to this special issue approach conversational storytelling from a multimodal perspective and provide analyses on the fine-grained coordination of verbal, para-verbal, and nonverbal action in face-to-face storytelling. This introduction first frames the individual contributions by providing an overview of the current topics and open research questions in the developing field of multimodal storytelling research. All individual papers are then briefly summarized and discussed in terms of their commonalities and their contribution to the developing field of multimodally-oriented research on conversational storytelling.
Multi-Scattering software: part I: online accelerated Monte Carlo simulation of light transport through scattering media
Authors: Jönsson Joakim , Berrocal Edouard
Published: November 2020

In this article we present and describe an online freely accessible software called Multi-Scattering for the modeling of light propagation in scattering and absorbing media. Part II of this article series focuses on the validation of the model by rigorously comparing the simulated results with experimental data. The model is based on the use of the Monte Carlo method, where billions of photon packets are being tracked through simulated cubic volumes. Simulations are accelerated by the use of general-purpose computing on graphics processing units, reducing the computation time by a factor up to 200x in comparison with a single central processing unit thread. By using four graphic cards on a single computer, the simulation speed increases by a factor of 800x. For an anisotropy factor g = 0.86, this enables the transport path of one billion photons to be computed in 10 seconds for optical depth OD = 10 and in 20 minutes for OD = 500. Another feature of Multi-Scattering is the integration and implementation of the Lorenz-Mie theory in the software to generate the scattering phase functions from spherical particles. The simulations are run from a computer server at Lund University, allowing researchers to log in and use it freely without any prior need for programming skills or specific software/hardware installations. There are countless types of scattering media in which this model can be used to predict light transport, including medical tissues, blood samples, clouds, smoke, fog, turbid liquids, spray systems, etc. An example of simulation results is given here for photon propagation through a piece of human head. The software also includes features for modeling image formation by inserting a virtual collecting lens and a detection matrix which simulate a camera objective and a sensor array respectively. The user interface for setting-up simulations and for displaying the corresponding results is found at: https://multi-scattering.com/.
Laser beam focusing through a moderately scattering medium using a bimorph mirror
Authors: Galaktionov Ilya , Sheldakova Julia , Nikitin Alexander , Samarkin Vadim , Parfenov Vadim , Kudryashov Alexis
Published: November 2020

The rarely considered case when the optical radiation passes through the weakly scattering medium, e.g. mid-density atmospheric fog with the number of scattering events up to 10 was investigated in this paper. We demonstrated an improvement of focusing of a laser beam (λ=0.65 µm) passed through the 5 mm-thick layer of scattering suspension of 1 µm polystyrene microbeads diluted in a distilled water. For the first time the low-order aberration corrector – wide aperture bimorph deformable mirror with 48 electrodes configured in 6 rings was used to optimize a far-field focal spot. We compared efficiencies of the algorithm that optimized the positions of the focal spots on Shack-Hartmann type sensor and the algorithm that optimized the peak brightness and the diameter of the far-field focal spot registered with a CCD. We experimentally demonstrated the increase of the peak brightness of the far-field focal spot by up to 60% due to the use of the bimorph deformable mirror for beam focusing through the scattering medium with concentration values of scatterers ranged from 105 to 106 mm−3.
Noise and distortion analysis of dual frequency comb photonic RF channelizers
Authors: Deakin Callum , Liu Zhixin
Published: November 2020

Dual frequency combs are emerging as highly effective channelizers for radio frequency (RF) signal processing, showing versatile capabilities in various applications including Fourier signal mapping, analog-to-digital conversion and sub-sampling of sparse wideband signals. Although previous research has considered the impact of comb power and harmonic distortions in individual systems, a rigorous and comprehensive performance analysis is lacking, particularly regarding the impact of phase noise. This is especially important considering that phase noise power increases quadratically with comb line number. In this paper, we develop a theoretical model of a dual frequency comb channelizer and evaluate the signal to noise ratio limits and design challenges when deploying such systems in a high bandwidth signal processing context. We show that the performance of these dual comb based signal processors is limited by the relative phase noise between the two optical frequency combs, which to our knowledge has not been considered in previous literature. Our simulations verify the theoretical model and examine the stochastic noise contributions and harmonic distortion, followed by a broader discussion of the performance limits of dual frequency comb channelizers, which demonstrate the importance of minimizing the relative phase noise between the two frequency combs to achieve high signal-to-noise ratio signal processing.
Ion-exchanged waveguides in periodically poled Rb-doped KTiOPO4 for efficient second harmonic generation
Authors: Mutter Patrick , Kores Cristine C. , Widarsson Max , Zukauskas Andrius , Laurell Fredrik , Canalias Carlota
Published: November 2020

An ion-exchange process has been developed for periodically poled Rb-doped KTiOPO4 (RKTP) which warrants high efficiency and low loss channel waveguides. The domain stability was investigated, and it was found that domain gratings with uncharged walls could stand the ion-exchange process without deterioration. 3.1 mW of blue second harmonic light was generated from 74 mW of radiation at 940.2 nm coupled into an 8 µm wide and 7 mm long waveguide, corresponding to a normalized conversion efficiency of 115%/Wcm2. Waveguides in PPRKTP open the possibility for stable operation at high optical powers, as well as generating entangled photons at low optical powers, and enable the investigation of novel nonlinear processes such as counter-propagating interactions in a waveguide format.
High-speed physical key distribution based on dispersion-shift-keying chaos synchronization in commonly driven semiconductor lasers without external feedback
Authors: Wang Longsheng , Chao Meng , Wang Anbang , Gao Hua , Li Songsui , Guo Yuanyuan , Wang Yuncai , Yan Lianshan
Published: November 2020

We propose a scheme of high-speed physical key distribution based on dispersion-shift-keying chaos synchronization in two semiconductor lasers without external feedback (response lasers), which are driven by a common external-cavity semiconductor laser (drive laser). In this scheme, the dispersion introduces a laser field beating-induced nonlinear transformation to the outputs of drive laser and renders the correlation elimination between the drive and response lasers improving the security of key distribution. Moreover, the commonly driven lasers without external feedback constitute an open-loop synchronization configuration and yield a short synchronization recovery time of a subnanosecond supporting the implementation of high-speed key distribution. With these two merits, we numerically demonstrate a 1.2 Gb/s secure key distribution with a bit error ratio below 3.8×10−3.
Coherent synthetic aperture imaging for visible remote sensing via reflective Fourier ptychography
Authors: Xiang Meng , Pan An , Zhao Yiyi , Fan Xuewu , Zhao Hui , Li Chuang , Yao Baoli
Published: November 2020

Synthetic aperture radar can measure the phase of a microwave with an antenna, which cannot be directly extended to visible light imaging due to phase lost. In this Letter, we report an active remote sensing with visible light via reflective Fourier ptychography, termed coherent synthetic aperture imaging (CSAI), achieving high resolution, a wide field-of-view (FOV), and phase recovery. A proof-of-concept experiment is reported with laser scanning and a collimator for the infinite object. Both smooth and rough objects are tested, and the spatial resolution increased from 15.6 to 3.48 µm with a factor of 4.5. The speckle noise can be suppressed obviously, which is important for coherent imaging. Meanwhile, the CSAI method can tackle the aberration induced from the optical system by one-step deconvolution and shows the potential to replace the adaptive optics for aberration removal of atmospheric turbulence.
High-fidelity pixel-super-resolved complex field reconstruction via adaptive smoothing
Authors: Gao Yunhui , Cao Liangcai
Published: November 2020

Pixel super-resolution (PSR) techniques have been developed to overcome the sampling limit in lensless digital holographic imaging. However, the inherent non-convexity of the PSR phase retrieval problem can potentially degrade reconstruction quality by causing the iterations to tend toward a false local minimum. Furthermore, the ill posedness of the up-sampling procedure renders PSR algorithms highly susceptible to noise. In this Letter, we propose a heuristic PSR algorithm with adaptive smoothing (AS-PSR) to achieve high-fidelity reconstruction. By automatically adjusting the intensity constraints on the estimated field, the algorithm can effectively locate the optimal solution and converge with high reconstruction quality, pushing the resolution toward the diffraction limit. The proposed method is verified experimentally within a coherent modulation phase retrieval framework, achieving a twofold improvement in resolution. The AS-PSR algorithm can be further applied to other phase retrieval methods based on alternating projection.
Systems biology informed deep learning for inferring parameters and hidden dynamics
Authors: Yazdani Alireza , Lu Lu , Raissi Maziar , Karniadakis George Em
Published: November 2020

Mathematical models of biological reactions at the system-level lead to a set of ordinary differential equations with many unknown parameters that need to be inferred using relatively few experimental measurements. Having a reliable and robust algorithm for parameter inference and prediction of the hidden dynamics has been one of the core subjects in systems biology, and is the focus of this study. We have developed a new systems-biology-informed deep learning algorithm that incorporates the system of ordinary differential equations into the neural networks. Enforcing these equations effectively adds constraints to the optimization procedure that manifests itself as an imposed structure on the observational data. Using few scattered and noisy measurements, we are able to infer the dynamics of unobserved species, external forcing, and the unknown model parameters. We have successfully tested the algorithm for three different benchmark problems.
The DNA damage response is required for oocyte cyst breakdown and follicle formation in mice
Authors: Martínez-Marchal Ana , Huang Yan , Guillot-Ferriols Maria Teresa , Ferrer-Roda Mònica , Guixé Anna , Garcia-Caldés Montserrat , Roig Ignasi
Published: November 2020

Mammalian oogonia proliferate without completing cytokinesis, forming cysts. Within these, oocytes differentiate and initiate meiosis, promoting double-strand break (DSBs) formation, which are repaired by homologous recombination (HR) causing the pairing and synapsis of the homologs. Errors in these processes activate checkpoint mechanisms, leading to apoptosis. At the end of prophase I, in contrast with what is observed in spermatocytes, oocytes accumulate unrepaired DSBs. Simultaneously to the cyst breakdown, there is a massive oocyte death, which has been proposed to be necessary to enable the individualization of the oocytes to form follicles. Based upon all the above-mentioned information, we hypothesize that the apparently inefficient HR occurring in the oocytes may be a requirement to first eliminate most of the oocytes and enable cyst breakdown and follicle formation. To test this idea, we compared perinatal ovaries from control and mutant mice for the effector kinase of the DNA Damage Response (DDR), CHK2. We found that CHK2 is required to eliminate ~50% of the fetal oocyte population. Nevertheless, the number of oocytes and follicles found inChk2-mutant ovaries three days after birth was equivalent to that of the controls. These data revealed the existence of another mechanism capable of eliminating oocytes.In vitroinhibition of CHK1 rescued the oocyte number inChk2-/-mice, implying that CHK1 regulates postnatal oocyte death. Moreover, we found that CHK1 and CHK2 functions are required for the timely breakdown of the cyst and to form follicles. Thus, we uncovered a novel CHK1 function in regulating the oocyte population in mice. Based upon these data, we propose that the CHK1- and CHK2-dependent DDR controls the number of oocytes and is required to properly break down oocyte cysts and form follicles in mammals.
Stability of SARS-CoV-2 phylogenies
Authors: Turakhia Yatish , De Maio Nicola , Thornlow Bryan , Gozashti Landen , Lanfear Robert , Walker Conor R. , Hinrichs Angie S. , Fernandes Jason D. , Borges Rui , Slodkowicz Greg , Weilguny Lukas , Haussler David , Goldman Nick , Corbett-Detig Russell
Published: November 2020

The SARS-CoV-2 pandemic has led to unprecedented, nearly real-time genetic tracing due to the rapid community sequencing response. Researchers immediately leveraged these data to infer the evolutionary relationships among viral samples and to study key biological questions, including whether host viral genome editing and recombination are features of SARS-CoV-2 evolution. This global sequencing effort is inherently decentralized and must rely on data collected by many labs using a wide variety of molecular and bioinformatic techniques. There is thus a strong possibility that systematic errors associated with lab—or protocol—specific practices affect some sequences in the repositories. We find that some recurrent mutations in reported SARS-CoV-2 genome sequences have been observed predominantly or exclusively by single labs, co-localize with commonly used primer binding sites and are more likely to affect the protein-coding sequences than other similarly recurrent mutations. We show that their inclusion can affect phylogenetic inference on scales relevant to local lineage tracing, and make it appear as though there has been an excess of recurrent mutation or recombination among viral lineages. We suggest how samples can be screened and problematic variants removed, and we plan to regularly inform the scientific community with our updated results as more SARS-CoV-2 genome sequences are shared (https://virological.org/t/issues-with-sars-cov-2-sequencing-data/473andhttps://virological.org/t/masking-strategies-for-sars-cov-2-alignments/480). We also develop tools for comparing and visualizing differences among very large phylogenies and we show that consistent clade- and tree-based comparisons can be made between phylogenies produced by different groups. These will facilitate evolutionary inferences and comparisons among phylogenies produced for a wide array of purposes. Building on the SARS-CoV-2 Genome Browser at UCSC, we present a toolkit to compare, analyze and combine SARS-CoV-2 phylogenies, find and remove potential sequencing errors and establish a widely shared, stable clade structure for a more accurate scientific inference and discourse.
Oxidative stress-induced inflammation in susceptible airways by anthropogenic aerosol
Authors: Leni Zaira , Cassagnes Laure Estelle , Daellenbach Kaspar R. , El Haddad Imad , Vlachou Athanasia , Uzu Gaelle , Prévôt André S. H. , Jaffrezo Jean-Luc , Baumlin Nathalie , Salathe Matthias , Baltensperger Urs , Dommen Josef , Geiser Marianne
Published: November 2020

Ambient air pollution is one of the leading five health risks worldwide. One of the most harmful air pollutants is particulate matter (PM), which has different physical characteristics (particle size and number, surface area and morphology) and a highly complex and variable chemical composition. Our goal was first to comparatively assess the effects of exposure to PM regarding cytotoxicity, release of pro-inflammatory mediators and gene expression in human bronchial epithelia (HBE) reflecting normal and compromised health status. Second, we aimed at evaluating the impact of various PM components from anthropogenic and biogenic sources on the cellular responses. Air-liquid interface (ALI) cultures of fully differentiated HBE derived from normal and cystic fibrosis (CF) donor lungs were exposed at the apical cell surface to water-soluble PM filter extracts for 4 h. The particle dose deposited on cells was 0.9–2.5 and 8.8–25.4 μg per cm2of cell culture area for low and high PM doses, respectively. Both normal and CF HBE show a clear dose-response relationship with increasing cytotoxicity at higher PM concentrations. The concurrently enhanced release of pro-inflammatory mediators at higher PM exposure levels links cytotoxicity to inflammatory processes. Further, the PM exposure deregulates genes involved in oxidative stress and inflammatory pathways leading to an imbalance of the antioxidant system. Moreover, we identify compromised defense against PM in CF epithelia promoting exacerbation and aggravation of disease. We also demonstrate that the adverse health outcome induced by PM exposure in normal and particularly in susceptible bronchial epithelia is magnified by anthropogenic PM components. Thus, including health-relevant PM components in regulatory guidelines will result in substantial human health benefits and improve protection of the vulnerable population.
Decreased utilization of allocentric coordinates during reaching movement in individuals with autism spectrum disorder
Authors: Umesawa Yumi , Atsumi Takeshi , Fukatsu Reiko , Ide Masakazu
Published: November 2020

Despite numerous reports of abnormalities in limb motor controls in spatial orientation in individuals with autism spectrum disorder (ASD), the underlying mechanisms have not been elucidated. We studied the influence of allocentric coordinates on ongoing reaching movements, which has been reported to strongly affect the reaching movements of typically developing (TD) individuals. ASD and TD participants observed a target presented randomly on one of the four corners of a frame on a screen. After it disappeared, another frame was presented slightly shifted leftward/rightward. The participants touched the memorized position of the target relatively congruent with a reference frame (allocentric condition) or ignoring it (egocentric condition). Results suggested that TD individuals were apt to touch the positions in allocentric manner rather than egocentric manner, while ASDs did not show this prioritization. Our findings demonstrate that decreased utilization of visual landmarks in ongoing movement may underlie motor disabilities in autism.