bluuebunny/crossref_metadata_2025 huggingface dataset:
Discordance between invasive coronary flow reserve (CFR) and non-invasive myocardial flow reserve (MFR) in diffuse coronary ectasia (DCE)
Authors: Khalil Mohammed , Alibazoglu Deniz , Balci Cem Numan , Hussein Rawan , Abuwadi Abraham , Alibazoglu Haluk
Published: January 2020

Clinical use with evidence base for diagnostic and prognostic value of quantitative positron emission tomography(PET) myocardial perfusion imaging (MPI) in patients with known or suspected coronary artery disease has exponentially increased over the last decade. This case illustrates the very first time that stress myocardial blood flow(MBF) in absolute terms (ml/min/gram) and myocardial flow reserve(MFR) are augmented in three vessel diffuse coronary ectasia by N13-Ammonia PET MPI. Moreover, relative qualitative MPI demonstrated moderate-sized ischemia in right coronary artery territory with chronic total occlusion in middle segment; despite regional myocardial flow reserve remains above ischemic thresholds while regional stress myocardial blood flow is mildly reduced.
DNA interference by a mesophilic Argonaute protein, CbcAgo
Authors: García-Quintans Nieves , Bowden Laurie , Berenguer José , Mencía Mario
Published: January 2020

Background: The search for putative enzymes that can facilitate gene editing has recently focused its attention on Argonaute proteins from prokaryotes (pAgos). Though they are structural homologues of human Argonaute protein, which uses RNA guides to interfere with RNA targets, pAgos use ssDNA guides to identify and, in many cases, cut a complementary DNA target. Thermophilic pAgos from Thermus thermophilus, Pyrococcus furiosus and Methanocaldococcus jasmanii have been identified and thoroughly studied, but their thermoactivity makes them of little use in mesophilic systems such as mammalian cells.

Methods: Here we search for and identify CbcAgo, a prokaryotic Argonaute protein from a mesophilic bacterium, and characterize in vitro its DNA interference activity.

Results: CbcAgo efficiently uses 5’P-ssDNA guides as small as 11-mers to cut ssDNA targets, requires divalent cations (preferentially, Mn2+) and has a maximum activity between 37 and 42 °C, remaining active up to 55 °C. Nicking activity on supercoiled dsDNA was shown. However, no efficient double-strand breaking activity could be demonstrated.

Conclusions: CbcAgo can use gDNA guides as small as 11 nucleotides long to cut complementary ssDNA targets at 37ºC, making it a promising starting point for the development of new gene editing tools  for mammalian cells.
Paediatric morbidity and mortality in Sierra Leone. Have things changed after the 2014/2015 Ebola outbreak?
Authors: Sesay Tom , Denisiuk Olga , Zachariah Rony
Published: January 2020

Background: Sierra Leone was severely affected by the 2014/2015 Ebola outbreak which is likely to have had longer term repercussions on the health system including on paediatric morbidity and mortality. We thus assessed under-five morbidity and mortality for malaria, acute respiratory Infections (ARI)/pneumonia, watery diarrhoea and measles during the post-Ebola period in Sierra Leone and compared this with the pre- and intra-Ebola periods.

Methods: This was a retrospective cross-sectional study using program data from the District Health Information system (DHIS2) and sourced from 14 districts in Sierra Leone. It included under-five children from 1,250 health facilities country-wide. Study periods included: before (June 1 st, 2013-April 30 th, 2014); during (June 1 st, 2014-April 30 th, 2015); and after Ebola (June 1 st, 2016-April 30 th, 2017).

Results: Malaria, ARI/pneumonia and diarrhoea consultations declined during Ebola but recovered to pre-Ebola levels in the post-Ebola period.  During the post-Ebola period, there was a highly significant reduction in case-fatality for the first three morbidities compared to the pre-Ebola period (P<0.0001). Average number of measles cases increased from 48/month in the pre-Ebola period to 568/month (12-fold increase) post-Ebola. Although there was no difference in measles case-fatality between the pre- and post-Ebola periods, case-fatality post-Ebola was significantly lower than during Ebola (Relative Risk: 0.05, 95% confidence interval 0.02-0.15, P<0.0001).

Conclusions: Consultations for under-five children at health facilities in Sierra Leone recovered to pre-Ebola levels and case-fatality for common childhood illnesses declined significantly. This is a change for the better. However, the high level of reported measles cases in the post-Ebola period indicates gaps in immune status and needs focused attention.
Staffing in public health facilities after the Ebola outbreak in rural Sierra Leone: How much has changed?
Authors: Squire James Sylvester , Hann Katrina , Denisiuk Olga , Zachariah Rony
Published: January 2020

Background:The 2014-2015 Ebola outbreak in Sierra Leone led the Ministry of Health and Sanitation to set minimum standards of staffing (medical/non-medical) at the district level for the provision of basic essential health services (BPEHS).

In one of the worst Ebola affected districts in Sierra Leone, we assessed staffing levels measured against these stipulated standards before, during, and 16 months after the Ebola outbreak.

Methods:The study population included all health workers in 83 health facilities. We assessed staffing levels at three points in time: pre-Ebola (April 2014); the end of the outbreak (November 2015); and 16 months post-Ebola (March 2017).

April 2014 was immediately prior to the Ebola outbreak and thus representative of the human resource situation before the outbreak. November 2015 was the month when Sierra Leone was declared Ebola-free, and thus reflects the end-situation after Ebola. March 2017 was two years since the launch of the BPEHS, and some progress should be expected.

Results:Against recommended medical staff numbers during pre-, intra- and post-Ebola periods, deficits were 67%, 65% and 60% respectively. Similarly, against recommended non-medical staff numbers during pre-, intra- and post-Ebola periods, the deficit remained at 92% throughout. In the post-Ebola period, there was a deficit of 73% against 1,389 recommended health worker positions.

Conclusions:Nothing has really changedin the state of human resources for health, and urgent measures are needed to rectify the situation and prevent adéjà vuin the advent of a new Ebola outbreak.
Applying inter-rater reliability to improve consistency in classifying PhD career outcomes
Authors: Stayart C. Abigail , Brandt Patrick D. , Brown Abigail M. , Dahl Tamara , Layton Rebekah L. , Petrie Kimberly A. , Flores-Kim Emma N. , Peña Christopher G. , Fuhrmann Cynthia N. , Monsalve Gabriela C.
Published: January 2020

Background: There has been a groundswell of national support for transparent tracking and dissemination of PhD career outcomes. In 2017, individuals from multiple institutions and professional organizations met to create the Unified Career Outcomes Taxonomy (UCOT 2017), a three-tiered taxonomy to help institutions uniformly classify career outcomes of PhD graduates. Early adopters of UCOT 2017, noted ambiguity in some categories of the career taxonomy, raising questions about its consistent application within and across institutions.

Methods: To test and evaluate the consistency of UCOT 2017, we calculated inter-rater reliability across two rounds of iterative refinement of the career taxonomy, classifying over 800 PhD alumni records via nine coders.

Results: We identified areas of discordance in the taxonomy, and progressively refined UCOT 2017 and an accompanying Guidance Document to improve inter-rater reliability across all three tiers of the career taxonomy. However, differing interpretations of the classifications, especially for faculty classifications in the third tier, resulted in continued discordance among the coders. We addressed this discordance with clarifying language in the Guidance Document, and proposed the addition of a flag system for identification of the title, rank, and prefix of faculty members. This labeling system provides the additional benefit of highlighting the granularity and the intersectionality of faculty job functions, while maintaining the ability to sort by - and report data on - faculty and postdoctoral trainee roles, as is required by some national and federal reporting guidelines. We provide specific crosswalk guidance for how a user may choose to incorporate our suggestions while maintaining the ability to report in accordance with UCOT 2017.

Conclusions: Our findings underscore the importance of detailed guidance documents, coder training, and periodic collaborative review of career outcomes taxonomies as PhD careers evolve in the global workforce. Implications for coder-training and use of novice coders are also discussed.
Case Report: Pseudoxanthoma elasticum
Authors: Lucas Catarina , Aranha João , da Rocha Isabel , Sousa Domingos
Published: January 2020

Pseudoxanthoma elasticum (PXE) is a rare inherited disorder, characterised by a progressive mineralization and fragmentation of elastic fibres of the skin, retina and cardiovascular system. At an initial stage, the skin usually exhibits distinctive lesions and subsequently extra-dermal manifestations. The diagnosis is based on clinical manifestations, histological analysis of the lesions and genetic analysis.

This is a case report of a 12-year-old child complaining of painless, mildly itchy yellow papules in the cervical region with 1 year of evolution.

PXE is currently an incurable disease and has a favourable prognosis when cardiovascular and retinal complications are prevented and monitored.
Consumer Privacy Choice in Online Advertising: Who Opts Out and at What Cost to Industry?
Authors: Johnson Garrett A. , Shriver Scott K. , Du Shaoyin
Published: January 2020

This paper studies consumers’ revealed privacy choice in online display advertising using real-world transaction data from an ad exchange.
THE EFFECTS OF TYPICAL THORIUM IMPURITIES ON THORIUM-BASED NUCLEAR FUELS
Authors: Alexander Jude S. , Edwards Geoffrey W.R. , Bromley Blair P. , Lane Keira
Published: January 2020

Natural thorium contains impurities of numerous isotopes. A study was performed to examine the influence of naturally occurring impurities in thorium-based fuels on a few parameters of interest such as: exit burnup, coolant void reactivity (CVR), fuel temperature coefficients (FTC), and the radiotoxicity of the used fuel. Two different fuel bundle designs were modeled: a 43-element bundle containing 2.25% U-233, and a 35-element bundle containing 1.45% U-233. Naturally occurring thorium fuel impurities were applied to both fuel bundle models at various concentrations, from 0% to 100% of the expected maximum. For burnup-averaged k-infinity (k∞) values of 1.050 and 1.030, exit burnup, burnup-weighted CVR, and burnup-weighted FTC were calculated using the neutron transport code WIMS-AECL, and plotted against fraction of full impurity concentration to determine how the impurity levels affect these reactor physics parameters of interest.

For the most-realistic (for CANDU) burnup-averaged k∞ of 1.050, both the inhalation radiotoxicity and the production of U-232 were calculated using the fuel depletion code WOBI.

Up to the maximum impurity concentrations considered, no effects on the investigated fuel performance parameters were found to be greater than a few percent.
Primiparous women's narratives of confidence in the perinatal period
Authors: Khajehei Marjan , Swain Julie Ann , Wen Yuhang
Published: January 2020

Background

Pregnancy and childbirth are described as transitional phases or existential thresholds that childbearing women have to cross.

Aim

To gather insights into the personal experiences of women in pregnancy, labour and the days immediately after birth.

Methods

We conducted a qualitative study in the postpartum ward at Westmead Hospital. We invited 16 primiparous women who had given birth to a single baby to participate in our study. After the participants signed the consent form, we conducted individual, in-depth interviews. We analysed the data using thematic analysis.

Findings

Confidence was an overarching theme that contributed to the women's experiences of pregnancy, labour and the immediate days after birth. The experiences encompassed two main categories: positive experiences that aided in building confidence, and negative experiences that adversely affected women's confidence. The themes relating to positive experiences, including effective interpersonal relationships, knowledge promotion and positive self-concept, made the women feel more confident. The themes relating to negative experiences, including lack of control and feeling unprepared, made the women feel less confident in their mothering capabilities.

Conclusion

Confidence was the overarching theme in this study and knowledge was shown to be the fundamental feature of confidence.
The diagnosis and management of pulmonary embolism
Authors: Toplis Emma , Mortimore Gerri
Published: January 2020

Pulmonary embolism (PE) is a condition characterised by an obstruction of the pulmonary arterial system by one or more emboli. Advanced clinical practitioners are often faced with ruling out a diagnosis of PE in patients with non-specific symptoms such as dyspnoea and pleuritic chest pain, which can be fairly mild and therefore a diagnosis of PE easily missed. PEs can be a challenge to diagnose, especially in elderly people, since it can be difficult to differentiate their symptoms from other less serious illnesses. Widely used scoring tools are helpful to calculate a patient's probability of having a PE. The Wells score is the most widely used pre-test clinical probability indicator of PE used in the UK, which scores the patient's probability of having a PE based on their risk factors. The D-dimer test is a relatively simple investigation to rule out venous thromboembolism (VTE) but can be raised for various reasons other than PE. Computed tomography pulmonary angiography (CTPA) is regarded as the gold standard imaging modality for investigation of acute PE but ventilation-perfusion (VQ) scans can be used as an alternative imaging technique for diagnosing PE in those where CTPA is contraindicated. Thrombolysis is underused in clinical practice due to the fear of adverse bleeding events. Patients without a massive or sub-massive PE are treated with anticoagulant therapy, usually commencing with subcutaneous low-molecular-weight heparin and switching over to a direct oral anticoagulant (DOAC). There has been a shift away from treatment with warfarin for the prevention and treatment of VTE over the past decade.
SAFER: A mnemonic to improve safety-netting advice
Authors: Silverston Paul
Published: January 2020

Paul Silverston describes a mnemonic to help facilitate the development of symptom-based, patient safety-focused, safety-netting advice

In primary care, patients often present during the early stages of an illness, before the findings required to establish the correct diagnosis have developed. This creates the potential for both diagnostic uncertainty and diagnostic error. There is also the possibility that a patient diagnosed with a minor illness may subsequently develop an uncommon but serious complication of that illness. Patients must be made aware of these risks and given advice as to when they should seek a medical re-assessment of their symptoms. This is referred to as safety-netting advice. Patients and relatives need to know the specific symptoms and signs to check for and the criteria that would mandate the need for a re-assessment. It is essential that safety-netting advice is patient-centred and that the medical content of that advice is symptom-based and patient safety-focused. This article describes a mnemonic, SAFER, which can be used to improve the quality of the safety-netting advice given to patients.
Fingerprinting sengon (Falcatria moluccana) accessions resistant to boktor pest and gall rust disease using microsatellite markers
Authors: Siregar Ulfah Juniarti , DEWI RAHMAWATI  , APRILIYA DAMAYANTI
Published: January 2020

Abstract. Siregar UJ, Rahmawati D, Damayanti A. 2019. Fingerprinting sengon (Falcatria moluccana) accessions resistant to boktor pest and gall rust disease using microsatellite markers. Biodiversitas 20: 2698-2706. Sengon (Falcataria moluccana Miq.) is a multipurpose fast-growing tree species and widely planted as community forest in Indonesia. According to Indonesian Light Wood Association (ILWA) F. moluccana wood products coming from forest industries in Jawa worth US$ 244.46 million export to China alone. The wood dust also has high potential as source for biomass-based energy in the form of wood-pellet. Monoculture plantation however often suffers from stem borer pest, known as boktor (Xystrocera festiva) and a gall rust disease, caused by fungi Uromycladium falcatarium. This research was aimed to characterize accessions of resistant and susceptible sengon individuals to both gall rust disease as well as stem borer pest using microsatellite markers. Totally 50 accessions of resistant and of resistant to stem borer pest were collected from Sumedang, West Jawa Province, while 88 accessions of resistant and of resistant to gall rust disease were sampled from Kediri, East Jawa Province and Sukabumi, Indonesia. Eight microsatellite markers could amplify most of the accessions used in this study and produce polymorphic fragments. High genetic diversity was detected in all of F. moluccana populations, with He ranged from 0.431 to 0.650. AMOVA showed that most genetic variations come from within populations. A dendrogram based on Nei’s genetic distance (1972) clustered some resistant accessions to either stem borer pest or gall rust disease separately from susceptible ones.
The development of coffee cultivation in the traditional agroforestry of mixed-garden (dukuh lembur) to provide social-economic benefit for the Outer Baduy Community, South Banten, Indonesia
Authors: BUDIWATI S. ISKANDAR  , JOHAN ISKANDAR  , BUDI IRAWAN  , SUROSO  , Partasasmita Ruhyat
Published: January 2020

Abstract. Iskandar BS, Iskandar J, Irawan I, Suroso, Pasratasmita R. 2019. The development of coffee cultivation in the traditional agroforestry of mixed-garden (dukuh lembur) to provide social-economic benefit for the Outer Baduy Community, South Banten, Indonesia. Biodiversitas 20: 2958-2969. The Baduy community who resides in the Village of Kanekes, the Sub-district of Leuwidamar, the District of Lebak, South Banten has maintained the Sundanese tradition, particularly in practicing swidden farming (ngahuma). They practice swidden farming based on Traditional Ecological Knowledge (TEK) and belief. According to the Baduy tradition, the commercial plants, including coffee, clove, cacao, teak, and rubber have been prohibited to cultivate in Baduy area. However, because the population has increased rapidly and market economy has intensively penetrated the Baduy area, some commercial plants, including robusta coffee (Coffea canephora Pierre ex A. Froehner) have been introduced by the outer Baduy community. The objective of this study was to elucidate the traditional practice of the Outer Baduy in cultivating coffee trees that are integrated into the traditional agroforestry of mixed-garden (dukuh lembur or leuweung lembur). This study used qualitative method with some techniques of collecting data, including observation, participant observation, semi-structured interviews, and plant survey in the sample plots of the dukuh lembur. The results of the study showed that in 1980-s the robusta coffee plants were introduced by some Outer Baduy people and have since been planted in the dukuh lembur. In the past, because coffee was prohibited to be cultivated in Baduy area, the coffee trees were regularly cut during the purification of the Baduy tradition (pembersihan adat). Nowadays, however, the robusta coffee trees have been properly integrated into the existing dukuh lembur which is based on hybrid knowledge of TEK and scientific Western knowledge. The Outer Baduy coffee farming system has provided subsistence as a well commercial economy that may support the sustainability of the Outer Baduy swidden cultivation that is considered as the cultural identity of the Baduy community.
Prospects for developing an early maturing variety of Winged Bean (Psophocarpus tetragonolobus) in Bogor, Indonesia
Authors: Eagleton Graham
Published: January 2020

Abstract. Eagleton GE. 2019. Prospects for developing an early maturing variety of Winged Bean (Psophocarpus tetragonolobus) in Bogor, Indonesia. Biodiversitas 20: 3142-3152. To investigate the possibility of producing a more convenient, early-maturing cultivar of winged bean for vegetable growers in West Java, an early flowering accession introduced from Singapore Botanic Gardens (‘Singha’, the female parent) was crossed with a vegetatively vigorous, late-maturing, local winged bean accession (‘Bogor’, the male parent). The phenology and general performance of plants of the parental accessions and of their F1 and F2 hybrid generations were compared in the plant nursery of the Bogor Botanic Gardens (6036’ S, 106048’ E) in three successive experiments over ten months. In each of the three experimental plantings, the mean number of days to first open flower for the Bogor variety (B) was more than 40 days later than for the Singha variety (S). There was no significant difference in the average number of days to first open flower between F1 plants (S x B) and Singha plants in the first two experiments, but in the third experiment the F1 plants flowered 23 days later than the Singha parent. The phenological development of all genotypes, but especially the Bogor variety, appeared to be retarded by long daylengths. Out of nineteen F2 plants included in the third experiment, six flowered at least as early as the average of the early flowering Singha parent, nine overlapped the distribution for the F1 plants, while only two were as late as the Bogor parent. It was inferred that flowering time in this particular cross was influenced as much by dominance effects as by additive genetic effects, with early flowering dominant to late flowering. Plants in the first two experiments were severely affected by collar-rot disease with no difference between genotypes. In the third experiment, planted in a potting-mix in poly-bags that avoided the collar-rot, all plants of the Singha and most plants of the F1 and F2 generations became infected by false-rust disease Synchytrium psophocarpi (Rac.) Baumann, whereas none of the Bogor plants exhibited symptoms of false-rust. The results support the finding in a previous study by Aminah-Lubis and Sastrapradja (1981) that the resistance to false rust disease found in Bogor winged bean varieties is conferred by genes that are recessive to genes conferring susceptibility to the disease. This investigation has implications for breeding improved varieties of vegetable winged bean and for understanding the evolution of winged bean as a crop.
Short-range remote sensing of water quality by a handheld fluorosensor system
Authors: Lu Junchen , Yuan Ye , Duan Zheng , Zhao Guangyu , Svanberg Sune
Published: January 2020

Laser-induced fluorescence is a powerful measurement method for determining the concentration of organic pollutants as well as the amount of algae in water. It can be applied in remote sensing of natural waters and has the advantages of high speed and sensitivity. In this paper, we present a compact handheld fluorosensor system for water quality assessment. The power of the technique is demonstrated in measurements at a river system in South China.
Diagnosis of electrically active defects in CH3NH3PbI3 perovskite solar cells via admittance spectroscopy measurements
Authors: Xue Juanjuan , Hu Xiaobo , Guo YiXin , Weng Guoen , Jiang Jinchun , Chen Shaoqiang , Zhu Ziqiang , Chu Junhao
Published: January 2020

The defect properties of

C
H

3

N
H

3

P
b
I

3

solar cells with efficiencies ranging from 7.70% to 12.51% were investigated using admittance spectroscopy measurements. Trap levels of the same kind with activation energies varied in the range of 0.16–0.23 eV above the valence band were found for different samples and identified as an interface-type defect. Moreover, the defect parameters, including the capture cross section of the holes, capture lifetime of the holes, and defect density, were extracted, and their relationships with the cell efficiencies were investigated. The results indicated that, compared with other parameters, defect density is a critical factor for

C
H

3

N
H

3

P
b
I

3

solar cell performance.
Hyperspectral imaging enabled by an unmodified smartphone for analyzing skin morphological features and monitoring hemodynamics
Authors: He Qinghua , Wang Ruikang
Published: January 2020

We propose a novel method and system that utilizes a popular smartphone to realize hyperspectral imaging for analyzing skin morphological features and monitoring hemodynamics. The imaging system works based on a built-in RGB camera and flashlight on the smartphone. We apply Wiener estimation to transform the acquired RGB-mode images into “pseudo”-hyperspectral images with 16 wavebands, covering a visible range from 470nm to 620nm. The processing method uses weighted subtractions between wavebands to extract absorption information caused by specific chromophores within skin tissue, mainly including hemoglobin and melanin. Based on the extracted absorption information of hemoglobin, we conduct real-time monitoring experiments in the skin to measure heart rate and to observe skin activities during a vascular occlusion event. Compared with expensive hyperspectral imaging systems, the smartphone-based system delivers similar results but with very-high imaging resolution. Besides, it is easy to operate, very cost-effective and has a wider customer base. The use of an unmodified smartphone to realize hyperspectral imaging promises a possibility to bring a hyperspectral analysis of skin out from laboratory and clinical wards to daily life, which may also impact on healthcare in low resource settings and rural areas.
Enhanced responsivity of co-hyperdoped silicon photodetectors fabricated by femtosecond laser irradiation in a mixed SF6/NF3 atmosphere
Authors: Ma Sheng-Xiang , Liu Xiao-Long , Sun Hai-Bin , Zhao Yang , Hu Yue , Ning Xi-Jing , Zhao Li , Zhuang Jun
Published: January 2020

Co-hyperdoped silicon is fabricated on single crystalline Si substrate by using femtosecond-laser pulses in a mixed gas of

S
F

6

and

N
F

3

with different ratios. With the increase of the proportion of

N
F

3

in the mixed gas, the co-hyperdoped silicon shows increased crystallinity but decreased sub-bandgap absorption. Photodetectors are fabricated based on these samples without high-temperature thermal annealing. With the increase of the proportion of

N
F

3

, the photoelectric response first increases and then decreases. Photodetectors based on the co-hyperdoped (

N
F

3

/

S
F

6

, 35/35 kPa) material without high-temperature thermal annealing demonstrate high performance on photoresponsivity (

6

A

W

−
1

@

−
5

V

for 1050 nm), which is an order of magnitude higher compared with the photodetector made from S-hyperdoped silicon. The photoconductive gain accounts for the high responsivity.
Strong magnetic field enhancement and magnetic Purcell effect in a dielectric disk-ring composite nanocavity
Authors: Yang Yang , Zhu Bofeng , Dai Haitao
Published: January 2020

All-dielectric nanocavities with low dissipative absorption bring new opportunities for efficiently enhancing and confining the optical magnetic field. Recently, a high-index dielectric nanodisk with internal magnetic dipole (MD) mode has become a prominent candidate in accelerating the spontaneous decay of MD transitions in quantum emitters (known as the magnetic Purcell effect). In this paper, we numerically investigate a dielectric disk-ring composite nanocavity that is capable of achieving 1 order of magnitude stronger enhancement of the magnetic field than a single disk. Multipole decomposition analysis further reveals the ultra-high enhancement is attributed to the huge MD radiation originating from the near-field (radiative) coupling between the MD mode and the electric quadrupole (magnetic octupole). More importantly, the numerical results also indicate such a composite nanocavity supports a stronger Purcell effect than a single disk under the excitation of an MD emitter, which can be verified by theoretical calculations. Further simulation demonstrates the better tolerance of the composite nanocavity on larger hole dimensions, thereby reducing the experimental difficulties in both structure fabrication and emitter loading. In addition, the dependence of the Purcell factor on the dipole orientation is investigated, demonstrating the great compatibility of the composite nanocavity. This presented design could open a promising avenue beyond the individual disk cavity for light–matter interactions in the magneto-optical domain.
Enhanced extinction ratios of metasurface polarizers by surface-plasmon interference
Authors: Kurosawa Hiroyuki , Inoue Shin-Ichiro
Published: January 2020

A numerical study demonstrates that an ultrahigh extinction ratio of

≥
3
×

10
9

is possible in a metasurface
polarizer. The metasurface has stacked complementary structures with
an air-hole array. From Babinet’s principle, this kind of metasurface
is known to have a high extinction ratio exceeding

10
4

. In this paper, numerical
calculations reveal that Babinet’s principle incorporating destructive
interference between localized and propagating surface plasmon
polariton resonances is key in the enormous enhancements in the
extinction ratio. Moreover, this study shows that an asymmetry in the
complementary structures plays a crucial role in the fine adjustments
of the interference. As a result, an extremely low transmittance is
realized, leading to an ultrahigh extinction ratio of

≥
3
×

10
9

in the O-band. An analytical study
confirms that the low transmittance associated with ultrahigh
extinction ratios originates from the destructive interference. Such
ultrahigh performances are wavelength-tunable by a simple scaling of
the metasurface and a fine adjustment of the interference. In the
C-band, the ultrahigh extinction ratio exceeds

200
×

10
9

. This study reveals the numerical and
theoretical design criteria for ultrahigh extinction ratios in
metasurface polarizers.
Cascaded nonlinearities in high-power femtosecond optical parametric oscillator
Authors: Stasevičius I. , Martynaitis G. , Vengris M.
Published: January 2020

A femtosecond optical parametric oscillator (OPO) pumped by the second harmonic of a Yb:KGW solid-state oscillator was investigated. A comparison between lithium triborate (LBO) and barium borate (BBO) crystals was carried out, with particular attention to the impact of phase mismatch on pulse characteristics. The phase mismatch induces cascaded nonlinearity, which acts as an effective nonlinear refractive index. Negative group delay dispersion of the resonator and the effective nonlinear refractive index allows soliton-like pulse formation with varying pulse durations and a bandwidth-limited time-bandwidth product. Deviation from the soliton equation was observed when intracavity power was varied. The measured pulse durations were lower than the classical soliton duration, indicating that the pulses were not classical solitons. A Z-scan experiment was used to determine nonlinear refractive indices under conditions identical to those in the oscillator cavity. Unexpectedly, the signs of nonlinear refraction as measured by the Z scan and indirectly observed in the OPO proved to be the opposite. This sign reversal could be interpreted in terms of the competing cascaded nonlinearities corresponding to self-phase modulation and cross-phase modulation between the signal and the pump pulses in the nonlinear OPO crystal.
Correcting non-photochemical quenching of Saildrone chlorophyll-a fluorescence for evaluation of satellite ocean color retrievals
Authors: Scott Joel P. , Crooke Scout , Cetinić Ivona , Del Castillo Carlos E. , Gentemann Chelle L.
Published: January 2020

In vivo chlorophyll fluorescence (ChlF) can serve as a reasonable estimator of in situ phytoplankton biomass with the benefits of efficiently and affordably extending the global chlorophyll (Chl) data set in time and space to remote oceanic regions where routine sampling by other vessels is uncommon. However, in vivo ChlF measurements require correction for known, spurious biases relative to other measures of Chl concentration, including satellite ocean color retrievals. Spurious biases affecting in vivo ChlF measurements include biofouling, colored dissolved organic matter (CDOM) fluorescence, calibration offsets, and non-photochemical quenching (NPQ). A more evenly distributed global sampling of in vivo ChlF would provide additional confidence in estimates of uncertainty for satellite ocean color retrievals. A Saildrone semi-autonomous, ocean-going, solar- and wind-powered surface drone recently measured a variety of ocean and atmospheric parameters, including ChlF, during a 60-day deployment in mid-2018 in the California Current region. Correcting the Saildrone ChlF data for known biases, including deriving an NPQ-correction, greatly improved the agreement between the drone measurements and satellite ocean color retrievals from MODIS-Aqua and VIIRS-SNPP, highlighting that once these considerations are made, Saildrone semi-autonomous surface vehicles are a valuable, emerging data source for ocean and ecosystem monitoring.
Tailoring modulation instabilities and four-wave mixing in dispersion-managed composite liquid-core fibers
Authors: Junaid Saher , Schaarschmidt Kay , Chemnitz Mario , Chambonneau Maxime , Nolte Stefan , Schmidt Markus A.
Published: January 2020

We show that the ultrafast nonlinear dynamics in supercontinuum generation can be tailored via mixture-based liquid core fibers. Samples containing mixtures of inorganic solvents allow changing dispersion from anomalous to normal, i.e., shifting zero dispersion across pump laser wavelength. A significant control over modulation instability and four-wave mixing has been demonstrated experimentally in record-long (up to 60 cm) samples in agreement with simulations when using sub-psec pulses at 1.555 µm. The smallest concentration ratio yields indications of soliton-fission based supercontinuum generation at soliton numbers that are beyond the coherence limit. The presented dispersion tuning scheme allows creating unprecedented dispersion landscapes for accessing unexplored nonlinear phenomena and selected laser sources.
Plasmon-hybridization-induced optical torque between twisted metal nanorods
Authors: Wu An’an , Tanaka Yoshito Y. , Shimura Tsutomu
Published: January 2020

We present a numerical study of optical torque between two twisted metal nanorods due to the angular momentum of the electromagnetic field emerging from their plasmonic coupling. Our results indicate that the interaction optical torque on the nanorods can be strongly enhanced by their plasmon coupling, which highly depends on not only the gap size but also the twisted angle between the nanorods. The behaviors of the optical torque are different between two plasmon coupling modes: hybridized bonding and anti-bonding modes with different resonances. The rotations of the twisted nanorods with the bonding and anti-bonding mode excitations lead to mutually parallel and perpendicular alignments, respectively. At an incident intensity of 10 mW/μm2, the rotational potential depths are more than 30 times as large as the Brownian motion energy, enabling the optical alignments with angle fluctuations less than ∼±10°. Thus, this optical alignment of the nanoparticles with the plasmon coupling allows dynamic control of the plasmonic characteristics and functions.
Finding spatiotemporal light bullets in multicore and multimode fibers
Authors: Chekhovskoy I. S. , Shtyrina O. V. , Wabnitz S. , Fedoruk M. P.
Published: January 2020

A two-level iterative algorithm for finding stationary solutions of coupled nonlinear Schrödinger equations describing the propagation dynamics of an electromagnetic pulse in multimode and multicore optical fibers of various structures was developed and tested. Using as an example the proposed analytical soliton solution which is localized in space and time, test calculations were performed, and the convergence of the algorithm was demonstrated.
Single beam low frequency 2D Raman spectroscopy
Authors: Hurwitz Ilan , Raanan Dekel , Ren Liqing , Frostig Hadas , Oulevey Patric , Bruner Barry D. , Dudovich Nirit , Silberberg Yaron
Published: January 2020

Low frequency Raman spectroscopy resolves the slow vibrations resulting from collective motions of molecular structures. This frequency region is extremely challenging to access via other multidimensional methods such as 2D-IR. In this paper, we describe a new scheme which measures 2D Raman spectra in the low frequency regime. We separate the pulse into a spectrally shaped pump and a transform-limited probe, which can be distinguished by their polarization states. Low frequency 2D Raman spectra in liquid tetrabromoethane are presented, revealing coupling dynamics at frequencies as low as 115 cm−1. The experimental results are supported by numerical simulations which replicate the key features of the measurement. This method opens the door for the deeper exploration of vibrational energy surfaces in complex molecular structures.
Observation of PT-symmetry in a fiber ring laser
Authors: Fan Zhiqiang , Zhang Weifeng , Qiu Qi , Yao Jianping
Published: January 2020

A wavelength-tunable single-mode laser with a sub-kilohertz linewidth based on parity-time (PT)-symmetry is proposed and experimentally demonstrated. The proposed PT-symmetric laser is implemented based on a hybrid use of an optical fiber loop and a thermally tunable integrated microdisk resonator (MDR). The MDR, implemented based on the silicon-on-insulator, operates with the optical fiber loop to form two mutually coupled cavities with an identical geometry. By controlling two light waves passing through the two cavities, with one having a gain coefficient and the other a loss coefficient but with an identical magnitude, a PT-symmetric laser is implemented. Thanks to an ultranarrow passband of the cavity due to PT-symmetry, single-longitudinal mode lasing is achieved. The tuning of the wavelength is implemented by thermally tuning the MDR. The proposed PT-symmetric laser is demonstrated experimentally. Single-longitudinal mode lasing at a wavelength of around 1555 nm with a sub-kilohertz linewidth of 433 Hz is implemented. The lasing wavelength is continuously tunable from 1555.135 to 1555.887 nm with a tuning slope of 75.24 pm/°C.
Sparse hand-held probe for optoacoustic ultrasound volumetric imaging: an experimental proof-of-concept study
Authors: Azizian Kalkhoran Mohammad , Varray François , Stuart Savoia Alessandro , Vray Didier
Published: January 2020

We present an experimental proof-of-concept study on the performance of a sparse segmented annular array for optoacoustic imaging. A capacitive micromachined ultrasonic transducer was equipped with a negatively focused acoustic lens and scanned in an annular fashion to exploit the performance of the sparse array geometry proposed in our recent numerical studies [Biomed. Opt. Express 10, 1545 (2019)BOEICL2156-708510.1364/BOE.10.001545; J. Biomed. Opt. 23, 025004 (2018)JBOPFO1083-366810.1117/1.JBO.23.2.025004]. A dedicated water tank was made using a 3D printer for light delivery and mounting the sample. A phantom experiment was carried out to showcase the possibility of full-field optoacoustic ultrasound (OPUS) imaging and confirm the earlier numerical results. This proof of concept opens the door towards a prototype of OPUS imaging for (pre-) clinical studies.
Particle trapping and beaming using a 3D nanotip excited with a plasmonic vortex
Authors: Liu Kai , Maccaferri Nicolò , Shen Yuefeng , Li Xueyun , Zaccaria Remo Proietti , Zhang Xuejin , Gorodetski Yuri , Garoli Denis
Published: January 2020

Recent advances in nanotechnology have prompted the need for tools to accurately and noninvasively manipulate individual nano-objects. Among the possible strategies, optical forces have been widely used to enable nano-optical tweezers capable of trapping or moving a specimen with unprecedented accuracy. Here, we propose an architecture consisting of a nanotip excited with a plasmonic vortex enabling effective dynamic control of nanoparticles in three dimensions. The structure illuminated by a beam with angular momentum can generate an optical field that can be used to manipulate single dielectric nanoparticles. We demonstrate that it is possible to stably trap or push the particle from specific points, thus enabling a new, to the best of our knowledge, platform for nanoparticle manipulation.
Acoustic phonon sideband dynamics during polaron formation in a single quantum dot
Authors: Wigger Daniel , Karakhanyan Vage , Schneider Christian , Kamp Martin , Höfling Sven , Machnikowski Paweł , Kuhn Tilmann , Kasprzak Jacek
Published: January 2020

When an electron–hole pair is optically excited in a semiconductor quantum dot, the host crystal lattice adapts to the presence of the generated charge distribution. Therefore, the coupled exciton–phonon system has to establish a new equilibrium, which is reached in the form of a quasiparticle called a polaron. Especially, when the exciton is abruptly generated on a timescale faster than the typical lattice dynamics, the lattice cannot follow adiabatically. Consequently, rich dynamics on the picosecond timescale of the coupled system is expected. In this study, we combine simulations and measurements of the ultrafast, coherent, nonlinear optical response, obtained by four-wave mixing (FWM) spectroscopy, to resolve the formation of this polaron. By detecting and investigating the phonon sidebands in the FWM spectra for varying pulse delays and different temperatures, we have access to the influence of phonon emission and absorption processes, which finally result in the emission of an acoustic wave packet.
Thermal-induced luminescence enhancement of BAC-P in bismuth-doped phosphogermanosilicate fibers
Authors: Zhao Qiancheng , Hao Qun , Luo Yanhua , Peng Gang-Ding
Published: January 2020

The thermal quenching effect has been systematically investigated in bismuth (Bi)-doped phosphogermanosilicate fiber with varying thermal conditions. For the first time, to the best of our knowledge, the activation of phosphor-related Bi active center (BAC-P) is achieved by thermal quenching at 400°C with a heating time of 10 min, evidenced by the enhanced luminescence of BAC-P (

∼

1.3

times) at 1300 nm. The experimental results reveal that a relatively low heating temperature with prolonged heating time stimulates the growth of BAC-P, whereas higher operating temperatures (

≥

500
∘

C) result in the irreversible destruction of BAC-P. The underlying mechanism for the thermally stimulated BAC-P process is also analyzed and discussed.
Transport of intensity equation based photon-counting phase imaging
Authors: Gupta Alok K. , Nishchal Naveen K. , Banerjee Partha P.
Published: January 2020

In low light conditions, such as in astronomy and non-invasive bio-imaging applications, the imaging performance is mostly degraded due to noise. In this paper, we demonstrate a transport of intensity equation based technique that uses photon-counting phase imaging. To achieve the phase imaging in a photon starved condition, a method proposed by Paganin et al. [J. Micros. 214, 51 (2004)10.1111/j.0022-2720.2004.01295.x] has been used. The method uses the fact that the magnitude of the wavefront curvature determines the quality of the recovered phase image for a given noise level and defocus distance. The effectiveness of the proposed method has been illustrated through simulations and experimental results using inexpensive partially coherent illumination. The study can find applications in non-invasive phase imaging.
Facilitated tip-enhanced Raman scattering by focused gap-plasmon hybridization
Authors: Chen Houkai , Zhang Yuquan , Dai Yanmeng , Min Changjun , Zhu Siwei , Yuan Xiaocong
Published: January 2020

Tip-enhanced Raman scattering (TERS) spectroscopy is a nondestructive and label-free molecular detection approach that provides high sensitivity and nanoscale spatial resolution. Therefore, it has been used in a wide array of applications. We demonstrate a gap-plasmon hybridization facilitated by a bottom-illuminated TERS configuration. The gap-plasmon hybridization effect is first performed with the finite-difference time-domain method to optimize the parameters, and experiments are then conducted to calibrate the performance. The results demonstrate an enhancement factor of 1157 and a spatial resolution of 13.5 nm. The proposed configuration shows great potential in related surface imaging applications in various fields of research.
Homo narrator. De cómo contamos historias a lo largo de la vida
Authors: García Hernández Alfonso Miguel
Published: January 2020

En esta editorial el autor reflexiona sobre las narrativas como fuente de conocimiento de las experiencias vinculando perspectivas transdisciplinares (enfermería, biología, antropología), y revela la utilidad de estos materiales narrativos como medios de construcción de significados que contribuyen a un mejor entendimiento de la vida.
Toxoplasma gondii seropositivity and the associated risk factors in sheep and pregnant women in El-Minya Governorate, Egypt
Authors: Abdelbaset Abdelbaset E. , Hamed Maha I. , Abushahba Mostafa F. N. , Rawy Mohamed S. , Sayed Amal S. M. , Adamovicz Jeffrey J.
Published: January 2020

Background and Aim: The cosmopolite protozoan, Toxoplasma gondii, has a significant economic and medical impact. Cats traditionally play a predominant role in the disease maintenance cycle; however, humans can be infected as a result of milk and meat consumption of Toxoplasma-infected livestock. In addition, infected pregnant women, even symptomless, can pass the disease to their unborn fetus. The limited clinical records and absence of specific national educational programs in countries like Egypt underscore the need for periodic toxoplasmosis disease evaluation. Here, we identified T. gondii seroprevalence among sheep and pregnant women and the associated risk factors in El-Minya Governorate, Egypt. Materials and Methods: Using peripheral blood, we detected T. gondii-specific antibodies in 151 sheep and 96 pregnant women sera from El-Minya Governorate using latex agglutination and indirect enzyme-linked immunosorbent assay. The impact of different environmental and behavioral risk factors identified with in-person interviews and serology results on acquiring toxoplasmosis was statistically analyzed. Results: The overall toxoplasmosis seroprevalence was 39.1% and 22.9% in sheep and pregnant women, respectively. Significantly higher seroprevalence was correlated with increasing sheep age and geographical location. Nonetheless, no statistical significance was found based on abortion history and pregnancy status of the examined sheep. Exposure factors important for pregnant women included pregnancy trimester, contact with cats, and the habit of eating undercooked sheep meat, which all had a statistically significant association with Toxoplasma seropositivity. Conclusion: The current study confirms increased antibodies against toxoplasmosis in both sheep and pregnant women in El-Minya Governorate and a clear association between women's age, contact with cats, and the habit of eating undercooked sheep meat and seroreactivity to T. gondii. These results strongly suggest the need for a more comprehensive epidemiological study and public health awareness education for toxoplasmosis.