SciSciNet: A large-scale open data lake for the science of science research.

The science of science has attracted growing research interests, partly due to the increasing availability of large-scale datasets capturing the innerworkings of science. These datasets, and the numerous linkages among them, enable researchers to ask a range of fascinating questions about how science works and where innovation occurs. Yet as datasets grow, it becomes increasingly difficult to track available sources and linkages across datasets. Here we present SciSciNet, a large-scale open data lake for the science of science research, covering over 134M scientific publications and millions of external linkages to funding and public uses. We offer detailed documentation of pre-processing steps and analytical choices in constructing the data lake. We further supplement the data lake by computing frequently used measures in the literature, illustrating how researchers may contribute collectively to enriching the data lake. Overall, this data lake serves as an initial but useful resource for the field, by lowering the barrier to entry, reducing duplication of efforts in data processing and measurements, improving the robustness and replicability of empirical claims, and broadening the diversity and representation of ideas in the field.

Identification of RNU44 as an Endogenous Reference Gene for Normalizing Cell-Free RNA in Tuberculosis.

Background: Normalization of cell-free RNA (cf-RNA) concentration can be affected by variable experimental conditions and thus impact the performance of their diagnostic potential. Our study aimed to identify appropriate endogenous reference genes for cf-RNA biomarker evaluation in the diagnosis of tuberculosis (TB). Methods: Subjects consisting of patients with TB with and without malignancy, patients with pneumonia, and healthy controls were recruited. Candidate reference genes were screened and identified by literature reviewing and RNA-Seq analysis. Expression levels of the candidate genes were determined by reverse-transcription real-time quantitative polymerase chain reaction in plasma from patients with TB and healthy controls. The stability of gene expression was assessed by geNorm, NormFinder, BestKeeper, the Comparative Delta Ct method, and RefFinder. Differential expression of 2 small RNAs (sRNAs) encoding by genome of Mycobacterium tuberculosis in plasma of patients with TB were determined by both absolute quantification and relative quantification with candidate reference genes. Results: According to the stability ranking analyzed with the 5 computational programs, the top 4 candidates-miR-93, RNU44, miR-16, and glyceraldehyde 3-phosphate dehydrogenase-were used to normalize the transcript levels of 2 mycobacterial sRNAs, MTS2823 and MTS1338, which were observed to have higher copy numbers in the plasma of patients with TB. Normalization with RNU44 displayed significantly higher levels of the 2 M tuberculosis sRNAs in the patients' plasma than those of healthy controls. Conclusions: RNU44 was demonstrated as a proper endogenous gene for cf-RNA normalization in TB diagnosis.

Performance enhancement of deep-ultraviolet LEDs by using quaternary AlInGaN polarization-engineered multiple-symmetrical-stair quantum barriers without electron blocking layer.

In this paper, a structure design using quaternary AlInGaN as multiple-symmetrical-stair-shaped quantum barriers without an electron blocking layer is shown. The results show this design mitigates the droop effect to ∼0.1%, and the internal quantum efficiency reaches about 93.4%. It is believed that the better performance results from balanced electron and hole concentration and distribution of the current among the quantum wells, along with reduced non-radiative recombination. This work may be useful in the application of using quaternary AlInGaN materials as quantum barrier layers with computational simulations to design structures with electron-barrier-free layers.

Public use and public funding of science.

Knowledge of how science is consumed in public domains is essential for understanding the role of science in human society. Here we examine public use and public funding of science by linking tens of millions of scientific publications from all scientific fields to their upstream funding support and downstream public uses across three public domains-government documents, news media and marketplace invention. We find that different public domains draw from various scientific fields in specialized ways, showing diverse patterns of use. Yet, amidst these differences, we find two important forms of alignment. First, we find universal alignment between what the public consumes and what is highly impactful within science. Second, a field's public funding is strikingly aligned with the field's collective public use. Overall, public uses of science present a rich landscape of specialized consumption, yet, collectively, science and society interface with remarkable alignment between scientific use, public use and funding.

Prevalence and surveillance of tuberculosis in Yemen from 2006 to 2018.

Tuberculosis is a major public health issue in Yemen, a country located at the southwestern tip of the Arabian Peninsula, while the situation of tuberculosis had been further exacerbated since the war started in 2015. The objective of this study is to investigate the incidence of tuberculosis in Yemen before the outbreak of COVID-19, from 2006 to 2018. During the 13-year period, 92 482 patients were enrolled in the TB programme records from the 22 governorates. Almost equal number of cases were diagnosed between males and females (a male to female ratio, 1.03:1). A notable rising incidence was observed in all age groups starting from 2011. The sharpest increase occurred in children under age 15, rising by 8.0-fold from 0.5 in the period 2006-2010 to 4.1 in the period 2011-2018. Paediatric TB accounted for 9.6% of all reported cases. In terms of the patient residence, incidence has more than doubled in Sana'a city, Sana'a Gov., Hajjah and Saadah. Concomitant diseases with tuberculosis included diabetes mellitus (14.0%), brucellosis (6.1%), hepatitis (6.0%), rheumatoid arthritis (4.3%), renal disorders (2.5%) and HIV infection (2.5%). Development of interventions to reduce tuberculosis incidence in children and concomitant communicable diseases is urgently needed.

Screening of 20 Mycobacterium tuberculosis sRNAs in plasma for detection of active pulmonary tuberculosis.

BACKGROUND: Mycobacterium tuberculosis (MTB) sRNAs are abundant. However, the level of MTB sRNA in peripheral blood remains elusive. METHODS: Twenty MTB sRNAs annotated in the reference genome of H37Rv were detected in the plasma of 170 active pulmonary tuberculosis patients and 124 healthy people by qRT-PCR detection system. The differential expression of sRNAs were analyzed in two groups. The value of sRNAs for diagnosis of active tuberculosis were evaluated by ROC curve analysis. RESULTS: Eight of the 20 sRNAs (MTS2823, MTS0997, MTS1338, ASdes, G2, C8, mcr15 and MTS1082) were found in at least 50% of the samples detected. The relative expression levels of MTS2823, MTS0997, MTS1338 and ASdes in plasma of tuberculosis patients were statistically higher than those in healthy controls. ROC curve analysis showed that the AUC of MTS0997, MTS1338, MTS2823 and ASdes were 0.8935 (95% CI 0.8109-0.9760), 0.8722 (95% CI 0.7862-0.9581), 0.8208 (95% CI 0.7246-0.9170) and 0.5792 (95% CI 0.4240-0.7344), respectively. The AUC value of combination of MTS0997, MTS1338 and MTS2823 was 0.914 (95% CI 0.8281-0.9926). CONCLUSIONS: MTB sRNAs MTS2823, MTS0997 and MTS1338 have the potential to be plasma biomarkers for active pulmonary tuberculosis.

Author Correction: Quantifying the dynamics of failure across science, startups and security.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Scientific elite revisited: patterns of productivity, collaboration, authorship and impact.

Throughout history, a relatively small number of individuals have made a profound and lasting impact on science and society. Despite long-standing, multi-disciplinary interests in understanding careers of elite scientists, there have been limited attempts for a quantitative, career-level analysis. Here, we leverage a comprehensive dataset we assembled, allowing us to trace the entire career histories of nearly all Nobel laureates in physics, chemistry, and physiology or medicine over the past century. We find that, although Nobel laureates were energetic producers from the outset, producing works that garner unusually high impact, their careers before winning the prize follow relatively similar patterns to those of ordinary scientists, being characterized by hot streaks and increasing reliance on collaborations. We also uncovered notable variations along their careers, often associated with the Nobel Prize, including shifting coauthorship structure in the prize-winning work, and a significant but temporary dip in the impact of work they produce after winning the Nobel Prize. Together, these results document quantitative patterns governing the careers of scientific elites, offering an empirical basis for a deeper understanding of the hallmarks of exceptional careers in science.

Quantifying the dynamics of failure across science, startups and security.

Human achievements are often preceded by repeated attempts that fail, but little is known about the mechanisms that govern the dynamics of failure. Here, building on previous research relating to innovation1-7, human dynamics8-11 and learning12-17, we develop a simple one-parameter model that mimics how successful future attempts build on past efforts. Solving this model analytically suggests that a phase transition separates the dynamics of failure into regions of progression or stagnation and predicts that, near the critical threshold, agents who share similar characteristics and learning strategies may experience fundamentally different outcomes following failures. Above the critical point, agents exploit incremental refinements to systematically advance towards success, whereas below it, they explore disjoint opportunities without a pattern of improvement. The model makes several empirically testable predictions, demonstrating that those who eventually succeed and those who do not may initially appear similar, but can be characterized by fundamentally distinct failure dynamics in terms of the efficiency and quality associated with each subsequent attempt. We collected large-scale data from three disparate domains and traced repeated attempts by investigators to obtain National Institutes of Health (NIH) grants to fund their research, innovators to successfully exit their startup ventures, and terrorist organizations to claim casualties in violent attacks. We find broadly consistent empirical support across all three domains, which systematically verifies each prediction of our model. Together, our findings unveil detectable yet previously unknown early signals that enable us to identify failure dynamics that will lead to ultimate success or failure. Given the ubiquitous nature of failure and the paucity of quantitative approaches to understand it, these results represent an initial step towards the deeper understanding of the complex dynamics underlying failure.

A dataset of publication records for Nobel laureates.

A central question in the science of science concerns how to develop a quantitative understanding of the evolution and impact of individual careers. Over the course of history, a relatively small fraction of individuals have made disproportionate, profound, and lasting impacts on science and society. Despite a long-standing interest in the careers of scientific elites across diverse disciplines, it remains difficult to collect large-scale career histories that could serve as training sets for systematic empirical and theoretical studies. Here, by combining unstructured data collected from CVs, university websites, and Wikipedia, together with the publication and citation database from Microsoft Academic Graph (MAG), we reconstructed publication histories of nearly all Nobel prize winners from the past century, through both manual curation and algorithmic disambiguation procedures. Data validation shows that the collected dataset presents among the most comprehensive collection of publication records for Nobel laureates currently available. As our quantitative understanding of science deepens, this dataset is expected to have increasing value. It will not only allow us to quantitatively probe novel patterns of productivity, collaboration, and impact governing successful scientific careers, it may also help us unearth the fundamental principles underlying creativity and the genesis of scientific breakthroughs.

Water-bath assisted convective assembly of aligned silver nanowire films for transparent electrodes.

Manipulating Ag nanowire (AgNW) assembly to tailor the opto-electrical properties and surface morphology could improve the performance of next-generation transparent conductive electrodes. In this paper, we demonstrated a water-bath assisted convective assembly process at the temporary water/alcohol interface for fabricating hierarchical aligned AgNW electrodes. The convection flow plays an important role during the assembly process. The assembled AgNW film fabricated via three times orthogonal dip-coating at a water-bath temperature of 80 °C has a sheet resistance of 11.4 Ω sq(-1) with 89.9% transmittance at 550 nm. Moreover, the root mean square (RMS) of this assembled AgNW film was only 15.6 nm which is much lower than the spin-coated random AgNW film (37.6 nm) with a similar sheet resistance. This facile assembly route provides a new way for manufacturing and tailoring ordered nanowire-based devices.

Ultrafast, superhigh gain visible-blind UV detector and optical logic gates based on nonpolar a-axial GaN nanowire.

Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 10(4) A W(-1)) and EQE value (up to 10(5)), as well as ultrafast (<26 ms) response speed, which indicates that a balance between the photocurrent gain and the response speed has been achieved. Based on its excellent photoresponse performance, an optical logic AND gate and OR gate have been demonstrated for performing photo-electronic coupled logic devices by further integrating the fabricated GaN NW detectors, which logically convert optical signals to electrical signals in real time. These results indicate the possibility of using a nonpolar a-axial GaN NW not only as a high performance UV detector, but also as a stable optical logic device, both in light-wave communications and for future memory storage.

Enhanced photovoltaic performance of organic/silicon nanowire hybrid solar cells by solution-evacuated method.

A method has been developed to fabricate organic-inorganic hybrid heterojunction solar cells based on n-type silicon nanowire (SiNW) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) hybrid structures by evacuating the PEDOT:PSS solution with dip-dropping on the top of SiNWs before spin-coating (solution-evacuating). The coverage and contact interface between PEDOT:PSS and SiNW arrays can be dramatically enhanced by optimizing the solution-evacuated time. The maximum power conversion efficiency (PCE) reaches 9.22% for a solution-evacuated time of 2 min compared with 5.17% for the untreated pristine device. The improvement photovoltaic performance is mainly attributed to better organic coverage and contact with an n-type SiNW surface.

Performance enhancement of blue light-emitting diodes without an electron-blocking layer by using special designed p-type doped InGaN barriers.

In this study, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency (IQE) are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL. The simulation results also show that the LED without an EBL has severe efficiency droop. However, when the special designed p-type doped InGaN QW barriers are used, the efficiency droop is markedly improved and the electroluminescence (EL) emission intensity is greatly enhanced which is due to the improvement of the hole uniformity in the active region and small electron leakage.

Effect of the thickness of undoped GaN interlayers between multiple quantum wells and the p-doped layer on the performance of GaN light-emitting diodes.

InGaN based light-emitting diodes (LEDs) with undoped GaN interlayer of variant thicknesses grown by metal-organic chemical vapor deposition technique have been investigated. It was found that the thickness of undoped GaN interlayers affected LEDs' performance greatly. The LED with 50 nm undoped GaN interlayer showed higher light output power and lower reverse-leakage current compared with the others at 20 mA. Based on electrical and optical characteristics analysis and numerical simulation, these improvements are mainly attributed to the improvement of the quality of depletion region by inserting an undoped GaN layer, as well as reduction of the Shockley-Read-Hall recombination in InGaN/GaN MQWs.