bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating the number of undetected COVID-19 cases among travellers from mainland China
Authors: Bhatia Sangeeta , Imai Natsuko , Cuomo-Dannenburg Gina , Baguelin Marc , Boonyasiri Adhiratha , Cori Anne , Cucunubá Zulma , Dorigatti Ilaria , FitzJohn Rich , Fu Han , Gaythorpe Katy , Ghani Azra , Hamlet Arran , Hinsley Wes , Laydon Daniel , Nedjati-Gilani Gemma , Okell Lucy , Riley Steven , Thompson Hayley , van Elsland Sabine , Volz Erik , Wang Haowei , Wang Yuanrong , Whittaker Charles , Xi Xiaoyue , Donnelly Christl A. , Ferguson Neil M.
Published: June 2020

Background: Since the start of the COVID-19 epidemic in late 2019, there have been more than 152 affected regions and countries with over 110,000 confirmed cases outside mainland China.

Methods: We analysed COVID-19 cases among travellers from mainland China to different regions and countries, comparing the region- and country-specific rates of detected and confirmed cases per flight volume to estimate the relative sensitivity of surveillance in different regions and countries.

Results: Although travel restrictions from Wuhan City and other cities across China may have reduced the absolute number of travellers to and from China, we estimated that more than two thirds (70%, 95% CI: 54% - 80%, compared to Singapore; 75%, 95% CI: 66% - 82%, compared to multiple countries) of cases exported from mainland China have remained undetected.

Conclusions: These undetected cases potentially resulted in multiple chains of human-to-human transmission outside mainland China.
New technologies to improve healthcare in low- and middle-income countries: Global Grand Challenges satellite event, Oxford University Clinical Research Unit, Ho Chi Minh City, 17th-18th September 2019
Authors: Ngoc Dinh Minh , Nygate Joseph , Hoang Minh Tu Van , Thwaites C. Louise ,   Global Grand Challenges Event Vietnam Group
Published: June 2020

We report the outputs of a satellite event in Ho Chi Minh City, Vietnam, organized as part of the “2nd Global Grand Challenges of Engineering Summit”. The event considered challenges and potential solutions for improving low- and middle-income country (LMIC) healthcare systems, with particular reference to critical care.  Participants from key regional and local stakeholders in healthcare and engineering discussed how new advances in technology, especially in the field of Artificial Intelligence, could be of potential benefit. This article summarizes the perspectives and conclusions of a group of key stakeholders from LMICs across South and South East Asia.
Not in the Job Description: The Commercial Activities of Academic Scientists and Engineers
Authors: Cohen Wesley M. , Sauermann Henry , Stephan Paula
Published: June 2020

Scholarly work seeking to understand academics’ commercial activities often draws on abstract notions of the academic reward system and the representative scientist. Few scholars have examined whether and how scientists’ motives to engage in commercial activities differ across fields. Similarly, efforts to understand academics’ choices have focused on three self-interested motives—recognition, challenge, and money—ignoring the potential role of the desire to have an impact on others. Using panel data for a national sample of over 2,000 academics employed at U.S. institutions, we examine how the four motives are related to commercial activity measured by patenting. We find that all four motives are correlated with patenting, but these relationships differ systematically between the life sciences, physical sciences, and engineering. These field differences are consistent with differences across fields in the rewards from commercial activities as well as in the degree of overlap between traditional and commercializable research, which affects the opportunity costs of time spent away from “traditional” academic work. We discuss potential implications for policy makers, administrators, and managers as well as for future research on the scientific enterprise.

This paper was accepted by Toby Stuart, entrepreneurship and innovation.
Heavy Traffic Limits for Join-the-Shortest-Estimated-Queue Policy Using Delayed Information
Authors: Atar Rami , Lipshutz David
Published: June 2020

We consider a load-balancing problem for a network of parallel queues in which information on the state of the queues is subject to a delay. In this setting, adopting a routing policy that performs well when applied to the current state of the queues can perform quite poorly when applied to the delayed state of the queues. Viewing this as a problem of control under partial observations, we propose using an estimate of the current queue lengths as the input to the join-the-shortest-queue policy. For a general class of estimation schemes, under heavy traffic conditions, we prove convergence of the diffusion-scaled process to a solution of a so-called diffusion model, in which an important step toward this goal establishes that the estimated queue lengths undergo state-space collapse. In some cases, our diffusion model is given by a novel stochastic delay equation with reflection, in which the Skorokhod boundary term appears with delay. We illustrate our results with examples of natural estimation schemes, discuss their implementability, and compare their relative performance using simulations.
Dynamic Optimization for Airline Maintenance Operations
Authors: Lagos Carlos , Delgado Felipe , Klapp Mathias A.
Published: June 2020

The occurrence of unexpected aircraft maintenance tasks can produce expensive changes in an airline’s operation. When it comes to critical tasks, it might even cancel programmed flights. Despite this, the challenge of scheduling aircraft maintenance operations under uncertainty has received limited attention in the scientific literature. We study a dynamic airline maintenance scheduling problem, which daily decides the set of aircraft to maintain and the set of pending tasks to execute in each aircraft. The objective is to minimize the expected costs of expired maintenance tasks over the operating horizon. To increase flexibility and reduce costs, we integrate maintenance scheduling with tail assignment decisions. We formulate our problem as a Markov decision process and design dynamic policies based on approximate dynamic programming, including value function approximation, rolling horizon techniques, and a hybrid policy between the latter two that delivers the best results. In a case study based on LATAM airline, we show the value of dynamic optimization by testing our best policies against a simple airline decision rule and a deterministic relaxation with perfect future information. We suggest to schedule tasks requiring less resources first to increase utilization of residual maintenance capacity. Finally, we observe strong economies of scale when sharing maintenance resources between multiple airlines.
Two-Stage Stochastic Mixed-Integer Programming with Chance Constraints for Extended Aircraft Arrival Management
Authors: Khassiba Ahmed , Bastin Fabian , Cafieri Sonia , Gendron Bernard , Mongeau Marcel
Published: June 2020

The extended aircraft arrival management problem, as an extension of the classic aircraft landing problem, seeks to preschedule aircraft on a destination airport a few hours before their planned landing times. A two-stage stochastic mixed-integer programming model enriched by chance constraints is proposed in this paper. The first-stage optimization problem determines an aircraft sequence and target times over a reference point in the terminal area, called initial approach fix (IAF), so as to minimize the landing sequence length. Actual times over the IAF are assumed to deviate randomly from target times following known probability distributions. In the second stage, actual times over the IAF are assumed to be revealed, and landing times are to be determined in view of minimizing a time-deviation impact cost function. A Benders reformulation is proposed, and acceleration techniques to Benders decomposition are sketched. Extensive results on realistic instances from Paris Charles-de-Gaulle airport show the benefit of two-stage stochastic and chance-constrained programming over a deterministic policy.
Bilişim Teknolojileri Öğretmenlerinin Kodlama Öğretimine İlişkin Görüşleri: Manisa Örneği
Authors: EĞİN Figen , ARIKAN Yüksel Deniz
Published: June 2020

Bu araştırmanın amacı Bilişim Teknolojileri öğretmenlerinin, ortaokul düzeyinde kodlama öğretiminde kullandıkları kodlama araçlarına, öğretim yöntemlerine ve ölçme değerlendirme etkinliklerine ilişkin görüşlerini belirlemek ve kodlama öğretimi ile çeşitli değişkenler arasındaki uyumu incelemektir. Araştırma karma araştırma deseninde gerçekleştirilmiştir. Araştırma kapsamında ilk olarak araştırmacılar tarafından hazırlanan Bilişim Teknolojileri Öğretmenlerininin Kodlama Öğretimine İlişkin Görüşleri Anketi ile 105 Bilişim Teknolojileri öğretmeninin kodlama araçları, öğretim yöntemleri, ölçme ve değerlendirme araçlarına ilişkin görüşleri alınmıştır. Ardından 9 Bilişim Teknolojileri öğretmeni ile yarı-yapılandırılmış görüşmeler gerçekleştirilmiştir. Araştırmada nicel verilerin analizinde frekans, yüzde ve uyum analizi kullanılmış, nitel verilerin analizinde ise içerik analizi kullanılmıştır. Araştırmanın bulgularına göre Bilişim Teknolojileri öğretmenlerinin kodlama öğretiminde en çok blok tabanlı ve robotik kodlama araçlarını; gösterip yaptırma, oyun ve problem tabanlı öğretim etkinliklerini kullandıkları görülmüştür. Bilişim Teknolojileri öğretmenleri kodlama öğretiminde ölçme ve değerlendirme etkinliklerinde en çok uygulama sınavı, proje ve öğrenci ürün dosyası kullanmaktadırlar. Nicel veriler üzerinde yapılan analizler sonucunda Bilişim Teknolojileri öğretmenlerinin kodlama öğretimi deneyimi ile kullanılan ölçme ve değerlendirme araçları arasında anlamlı bir ilişki olduğu görülmüştür.
Endoscopic tattooing for colorectal lesions: impact on quality of care and patient outcomes
Authors: Nahid MAK , Shrestha AK , Imtiaz MR , Basnyat PS
Published: June 2020

Introduction

The National Bowel Cancer Screening Programme guidelines advocate the use of endoscopic tattooing for suspected malignant lesions to assist identification and to facilitate laparoscopic resections. However, endoscopic tattooing practices are variable in endoscopic units, resulting in repeat endoscopy and delay in patient management. The aim of this study was to assess the adherence to tattoo protocol for significant colonic lesions at an endoscopy unit in a large district general hospital.

Materials and methods

Prospectively collected data were analysed for 252 patients with significant colonic lesions between January 2017 and December 2018. Data were collected through reviewing patient’s notes, histopathology findings and endoscopy reports. Data on lesions, complications, number and site of tattoo placed, and any repeat endoscopy for a tattoo were collected.

Results

Of the 252 patients, 88% (n = 222) had malignant and 12% (n = 30) had benign lesions. Only 58.7% (n = 148) of those patients who had colonoscopy had tattoo placement reported. Of these 148 cases, the report stated the distance of tattoo in relation to the lesion in only 46% (n = 68) of patients. Unfortunately, 14.3% (n = 36) of patients required repeat endoscopy to tattoo the lesions prior to surgery.

Conclusions

Our study highlights the lack of uniformity of tattoo practice among endoscopists. Despite the National Bowel Cancer Screening Programme guidelines, a significant proportion of colorectal lesions are still not tattooed during their first endoscopy. Some patients had to have repeat endoscopy just for the purpose of tattooing. Active involvement and participation of all endoscopists in the colorectal and the complex polyp multidisciplinary teams may help to improve the tattoo service.
A review of the use of biological mesh products in modern UK surgical practice: a religious and cultural perspective
Authors: Koshy RM , Kane EG , Grocock C
Published: June 2020

Introduction

The UK is an increasingly multicultural society. This change coincides with an increasing use of animal products in medicine and surgery and a change in the UK law of consent. The refusal of Jehovah’s Witnesses to accept blood products is well known, but the use of animal products in surgery is a neglected topic. As society becomes more diverse and medicine becomes ever more advanced, there is increasing potential for a mismatch between what is medically possible and what is acceptable from a religious perspective.

Methods

Surgical products were identified by searching the literature and contacting manufacturing companies. Literature was identified by using PubMed and OVID (MEDLINE). Religious views were established by contacting national bodies for each group.

Findings

The views of common UK religious groups and the constituent parts of biological meshes are summarised in tables intended to be used as a reference during clinical practice. On an elective basis, the Islamic, Hindu. Sikh and Jain leaders contacted had strong views on avoiding animal derived products. The Christian and Jewish leaders contacted did not. All religious leaders contacted accepted the use of mesh derived from human tissue. All products, including those of porcine and bovine origin, were acceptable to all leaders contacted if the procedure was performed to save life. The highlighting of this issue should prompt earlier consideration and discussion in the surgical planning and the consenting process with all final decisions taken by both the surgeon and the individual patient.
Massive liver haemangioma causing Kasabach–Merritt syndrome in an adult
Authors: Alimoradi M , Sabra H , El-Helou E , Chahal A , Wakim R
Published: June 2020

Liver haemangiomas are common, but their size very rarely exceeds 40cm. Most people with liver haemangiomas are asymptomatic, and diagnosis is usually made incidentally during imaging for other complaints. When a liver haemangioma is symptomatic or produces complications, surgical intervention may be warranted. Kasabach–Merritt syndrome is an uncommon complication reported in certain rare vascular tumours in children, with only a few cases reported in adults. The syndrome describes a consumptive coagulopathy initiated within a vascular tumour, mainly tufted angiomas and kaposiform haemangioendotheliomas and, less commonly, giant haemangiomas. The process can extend beyond the tumour and become disseminated in certain cases due to trauma or surgery. The definitive treatment for giant liver haemangiomas can include arterial embolisation, surgical excision, hepatectomy or even liver transplantation. We report the case of a 32-year-old woman with a 42 × 32 × 27cm (18,870ml) liver haemangioma associated with Kasabach–Merritt syndrome. The diagnosis was challenging, even with proper imaging, owing to the rarity of the condition. It was achieved with an exploratory laparotomy with biopsy.
Characterization of micro-holes drilled in alumina ceramic by the combined pulse laser technique
Authors: Jia Xianshi , Zhu Guangzhi , Wang Hailin , Shan Ping , Aleksei Kozlov , Zhu Xiao
Published: June 2020

Nowadays, combined pulse laser (CPL) technology has shown obvious advantages in alumina ceramic drilling. However, the characterization of micro-holes drilled by the CPL is not clear. In this paper, micro-holes drilled by ns-ms and ns/ms CPLs are systematically compared from the aspects of hole diameter, cracks, spatter deposition, recast layer, re-solidified particles, grain size, and chemical composition. The results show that due to the synchronous output of the nanosecond laser, the ns/ms CPL can eject more melt through expelling of the plasma shock wave; thus, the recast layer, re-solidified particles, and oxygen vacancies are decreased, while the spatter deposition is increased. On the other hand, due to the higher temperature and larger temperature gradient introduced by the nanosecond laser, the hole diameter, cracks, and grain size are increased. Therefore, an ideal CPL method to optimize the drilling performance is proposed. The research results have important guidance for improving the processing quality of the CPL, especially for alumina ceramic laser processing.
Simulations of photothermal effects and thermodynamics induced by optical resonance in a fiber metallic Fabry–Perot cavity
Authors: Hao Pengfei , Li Min , Wen Xiaoyan , Ho Ho-Pui , Lu Haifei
Published: June 2020

Our simulations revealed that a highly localized optic-thermal transformation can lead to high temperatures in the fiber-based metallic Fabry–Perot cavity (FMFP) due to optical resonance. Both the transfer matrix method and finite difference time domain (FDTD) method are used for optical analysis of FMFP. Empirical formulas of maximum temperature were derived based on the superposition principle. Despite the fact that the derivation of the resonance condition for FMFP is usually discarded due to its complexity, we propose a simple resonance condition for a metallic Fabry–Perot cavity. In addition, suddenly tuning on the incident light will cause fast-decaying air pressure and velocity, which are also solved from nanosecond scale to equilibrium. This paper is useful for estimating the heat tolerance threshold of nanostructures on fiber end surfaces. Photothermal conversion in FMFP provides an excellent miniature heat source for applications that require high-efficiency photothermal conversion, and FMFP is particularly suitable for optofluidics.
Dual-band passband terahertz filter based on multilayer metamaterial
Authors: Li Jiu-sheng
Published: June 2020

We have theoretically verified the design of dual-band passband terahertz filter using multilayer metamaterial. The top and bottom layers are composed of periodically branching structure metallic patterns, which are exactly the same. The middle layer consists of a periodically metallic square aperture. The three metallic layers are separated by two thin dielectric layers. An equivalent circuit model is used to simplify the design procedure of the proposed structure. The performance of the terahertz filter is analyzed via equivalent circuit model together with the full wave CST method. The results show that the proposed structure provides two passbands. One is the center frequency of 0.32 THz with

−

3

d
B

bandwidth of 164 GHz, and the other is the center frequency of 0.74 THz with

−

3

d
B

bandwidth of 176 GHz.
Bound states in the continuum for optomechanical light control with dielectric metasurfaces
Authors: Rojas Hurtado Carol Bibiana , Dickmann Johannes , Feilong Bruns Florian , Siefke Thomas , Kroker Stefanie
Published: June 2020

We investigate a reconfigurable dielectric metasurface merging optomechanical interaction and quasi-bound states in the continuum promising for all-optical light control light. The surface consists of a dimerized high-contrast grating with a compliant bilayer structure. The optical forces induced by a control light field lead to structural deformations changing the optical response. We discuss requirements for the geometry and optical force distribution to enable an efficient optomechanical coupling, which can be exploited to tune reflectivity, phase and polarization of a beam impinging on the metasurface. Numerical results explore some tunable devices as mirrors, saturable output couplers, phase modulators and retarder plates.
Spatio-temporal discrimination of molecular, aerosol and cloud scattering and polarization using a combination of a Raman lidar, Doppler cloud radar and microwave radiometer
Authors: Wang Dongxiang , Stachlewska Iwona S. , Delanoë Julien , Ene Dragos , Song Xiaoquan , Schüttemeyer Dirk
Published: June 2020

The combined data from the ESA Mobile Raman Polarization and Water Vapor Lidar (EMORAL), the LATMOS Bistatic Doppler Cloud Radar System for Atmospheric Studies (BASTA), and the INOE Microwave Radiometer (HATPRO-G2) have been used to explore the synergy for the spatio-temporal discrimination of polarization and molecular, aerosol and cloud scattering. The threshold-based methodology is proposed to perform an aerosol-cloud typing using the three instruments. It is demonstrated for 24 hours of observations on 10 June 2019 in Rzecin, Poland. A new scheme for target classification, developed collaboratively by the FUW and the OUC, can help determine molecules, aerosol (spherical, non-spherical, fine, coarse), cloud phase (liquid, ice, supercooled droplets) and precipitation (drizzle, rain). For molecular, aerosol, and cloud discrimination, the thresholds are set on the backward scattering ratio, the linear particle depolarization ratio and the backscatter colour ratio, all calculated from lidar signals. For the cloud phase and precipitation categorization, the thresholds are set on the reflectivity and the Doppler velocity derived from cloud radar signals. For boundary layer particles, precipitation, and supercooled droplets separation, the thresholds are set on the profiles of temperature and relative humidity obtained by the microwave radiometer. The algorithm is able to perform separation even under complicated meteorological situation, as in the presented case study.
Hong-Ou-Mandel interference of unconventional temporal laser modes
Authors: Agne Sascha , Jin Jeongwan , Kuntz Katanya B. , Miatto Filippo M. , Bourgoin Jean-Philippe , Jennewein Thomas
Published: June 2020

The Hong-Ou-Mandel (HOM) effect ranks among the most notable quantum interference phenomena, and is central to many applications in quantum technologies. The fundamental effect appears when two independent and indistinguishable photons are superimposed on a beam splitter, which achieves a complete suppression of coincidences between the two output ports. Much less studied, however, is when the fields share coherence (continuous-wave lasers) or mode envelope properties (pulsed lasers). In this case, we expect the existence of two distinct and concurrent HOM interference regimes: the traditional HOM dip on the coherence length time scale, and a structured HOM interference pattern on the pulse length scale. We develop a theoretical framework that describes HOM interference for laser fields having arbitrary temporal waveforms and only partial overlap in time. We observe structured HOM interference from a continuous-wave laser via fast polarization modulation and time-resolved single photon detection fast enough to resolve these structured HOM dips.
Nanosecond parametric Raman anti-Stokes SrWO4 laser at 507 nm with collinear phase matching
Authors: Smetanin S. N. , Jelínek M. , Tereshchenko D. P. , Shukshin V. E. , Konyukhov M. V. , Papashvili A. G. , Voronina I. S. , Ivleva L. I. , Kubeček V.
Published: June 2020

Collinear phase matching of the Stokes ↔ anti-Stokes interaction for Raman-active crystals with different birefringence was studied theoretically as well as experimentally. It was shown that collinear phase matching of the Stokes ↔ anti-Stokes interaction in low-birefringent crystals can be insensitive to angular mismatch if a phase matching angle is higher than 60°. We have developed and experimentally realized an extracavity parametric Raman anti-Stokes laser based on a low-birefringent SrWO4. Cyan 507-nm anti-Stokes conversion from green (532 nm) pump radiation of a 5-ns, 1-mJ second harmonic Nd:YAG laser has been obtained. Laser setup with a single beam excitation made it possible to use an output face of the SrWO4 crystal as an output coupler because of wide (6°) angular tolerance of collinear phase matching that resulted in an increase of slope efficiency of anti-Stokes generation higher than 3% at the anti-Stokes energy output of a 10-µJ level.
Tunable continuous-wave laser operation of Tm3+:BaY2F8 near 2.3  µm
Authors: Muti Abdullah , Baylam Isınsu , Tonelli Mauro , Sennaroglu Alphan
Published: June 2020

We report, for the first time to our knowledge, tunable continuous-wave laser action in the

T
m

3
+

:

B
a
Y

2

F

8

(BYF) crystal near 2.3 µm. In the experiments, a BYF crystal doped with 3 at. % thulium was end pumped with a narrow-linewidth, tunable

T
i

3
+

:

s
a
p
p
h
i
r
e

laser with up to 920 mW of incident power. Lasing was achieved for the two pump polarizations of

E

/

/

x

and

E

/

/

y

. The best power performance was obtained in the case of

E

/

/

x

, double-end pumping, where 100 mW of output power was obtained at 2290 nm with 920 mW of pump power and 1% output coupler. The laser could be continuously tuned from 2233 to 2385 nm. Excitation spectra for

E

/

/

x

and

E

/

/

y

pumping were measured in the 760–810 nm range, and the optimum pumping wavelength was determined to be 779 nm for

E

/

/

x

. By using the lifetime and lasing threshold data, the stimulated emission cross section at 2290 nm was further determined to be

(

0.66

±
0.06
)
×

10

−
24

m

2

.
Ultracompact fiber all-optical router using a photo-controlled microbubble
Authors: Cao Kunjian , Liu Yi , Lang Changpeng , Xu Qinfeng , Zhao Yuan
Published: June 2020

An ultracompact fiber router based on a photo-controlled microbubble was proposed in this Letter. Because the microbubble can be repositioned precisely in the fiber microcavity by adjusting the drive laser power, the target light beam that was incident on the gas-liquid interface of the microbubble was routed toward different directions by the light refraction inside the photo-controlled microbubble. Experimental results showed that the device had a low insertion loss of 0.64 dB, response time of (

1.2

−

1.8

s

), and can achieve the continuous beam redirections within an angle range of 56° by exploiting a drive laser power of only 1.8 mW. With the characteristics of excellent controllability, low consumption, and no electromechanical parts, such a fiber all-optical router has potential to be used for the multiplex treatments and analysis applications of the photonic laboratory on a chip (PLOC).
Buildup dynamics of asynchronous vector solitons in a polarization-multiplexed dual-comb fiber laser
Authors: Zhao Kangjun , Gao Chenxin , Xiao Xiaosheng , Yang Changxi
Published: June 2020

Polarization-multiplexed dual-comb fiber lasers enable significant applications in dual-comb spectroscopy and optical sensing. However, the complexity of the underlying formation dynamics of dual-comb solitons has not been unveiled so far. Here, we capture the real-time spectral evolutions of both vector solitons from the initial fluctuations, with the help of the time-stretch dispersive Fourier transform technique. Both vector solitons experience the relaxation oscillation, quasi-mode-locking, beating dynamics, and mode locking, accompanying central wavelength shifts in opposite directions, which might be induced by the gain saturation during their buildup processes. Moreover, polarization-dependent gain in the gain fiber leads to the different buildup time of both vector solitons. Our findings open new perspectives for dual-comb buildup dynamics and might impact laser design for applications.
Dipole scattering of a short radiation pulse on hydrogen-like atoms
Authors: Shneider M. N. , Semak V. V.
Published: June 2020

Our theoretical model of forced dipole oscillation demonstrates that when the amplitude of the forcing field is changing fast, the oscillations of the bound electron in the atom or molecule initially proceed at two frequencies: the frequency of the natural electron oscillations and the frequency of the forcing field. Particularly, applied to the science of scattering, this model of transient forced atomic and molecular oscillations suggests that accurate interpretation of the laser scattering experiments using short laser pulses must include both the conventionally known scattering at the laser frequency (Rayleigh) and the predicted by our theoretical spectral emission that corresponds to the natural frequency of the electronic oscillations. This article presents the results of numerical simulations using our model performed for the hydrogen atom. The characteristics of the components of scattered radiation, their polarization, and Doppler thermal broadening are discussed.
Comunicação, educação e vigilância popular em saúde em tempos de COVID-19 – a experiência das comunidades de Niterói, RJ
Authors: Latgé Paula Kwamme , Araújo Daniela Nunes , Silva Júnior Aluísio Gomes da
Published: June 2020

O acesso à internet, renda mínima e à segurança alimentar no contexto  do coronavírus (COVID-19) evidenciam a fragilidade social. Neste contexto, um grupo de jovens comunicadores da cidade de Niterói no Rio de Janeiro foi mobilizado pela OSC BemTV Educação e Comunicação para compor um capaz de enfrentar  as dificuldades de acesso à internet e construir coletivamente a checagem de informações, combate a notícias falsas, capilarização do acesso e fortalecimento das políticas e estratégias para conter a exponencialidade da contaminação comunitária.
Psychometric properties of the Portuguese version of the Achievement Emotions Questionnaire for Elementary School
Authors: Sanches Cristina , Monteiro Vera , Mata Lourdes , Santos Natalie , Gomes Marta
Published: June 2020

Os principais objetivos do corrente estudo consistiram na tradução e adaptação do Achievement Emotions Questionnaire – Elementary School (AEQ-ES) para Português e na análise das suas propriedades psicométricas. Uma amostra de 350 alunos portugueses do terceiro e quarto ano de escolaridade (com idades compreendidas entre os 7 e os 12 anos) completou a versão portuguesa do AEQ-ES (AEQ-ES-P). Tal como a versão original, o AEQ-ES-P mede o prazer, o aborrecimento e a ansiedade dos alunos em relação à matemática em três contextos académicos: assistir a aulas, fazer os trabalhos de casa e fazer testes. A análise fatorial confirmatória corroborou a estrutura hierárquica do AEQ-ES-P, que também se mostrou invariante entre géneros e anos de escolaridade. O instrumento mostrou também boa fiabilidade e estabilidade temporal. Foram encontradas correlações significativas na direção esperada entre o prazer, a ansiedade e o aborrecimento, bem como entre essas emoções, as perceções de competência dos alunos e a sua motivação intrínseca para a matemática, apoiando assim a validade interna e externa do questionário. Estes resultados indicam que o AEQ-ES-P apresenta boas propriedades psicométricas e é adequado para medir as emoções de realização de crianças portuguesas do terceiro e do quarto ano de escolaridade no domínio da matemática.
Theoretical Study of Diels-Alder Reaction of But-3-en-2-one with Hexa-1,2,4-triene: A Density Functional Theory Study
Authors: Hassan Rezan J. , Abdallah Hassan H.
Published: June 2020

The Diels-Alder reaction between but-3-en-2-one with hexa-1,2,4-triene was studied using density functional theory method at B3LYP-D3/6-311++G(d,p) level of theory. The geometries of the transition states were determined. Moreover, calculations of the vibrational frequencies permitted computation of the activation enthalpies and entropies. The computational results show that the cycloadducts from trans conformer have the lower relative energies (−46.48 and −47.50 kcal/mol) as compared to the cis conformer of cycloadducts (−44.45 and −45.87 kcal/mol). The global reactivity indices were analyzed at the ground state of reactants to predict the reactivity of the studied organic molecules in the cycloaddition reactions. The electronic chemical potential of hexa-1,2,4-trien found to be than but-3-en-2-one, which indicates that the net charge transfer will be from hexa-1,2,4-trien toward the electron-deficient but-3-en-2-one reactant.
Evaluation of IgG, IgM, CD4+ and CD8+ T cells during neoadjuvant chemotherapy with Tezio and Apatinib in gastric cancer patients
Authors: Cui Zhe , Zhang Jianjun , Zhang Jing , Xu Lan
Published: June 2020

This experiment was carried out to study the effect the neoadjuvant chemotherapy with Tezio and Apatinib on the treatment of advanced gastric cancer and its impact on the postoperative immune function of patients' function. The patients with advanced gastric cancer who were treated in gastrointestinal surgery in our hospital from January 2017 to December 2018 were divided into two groups. The new chemotherapy and the traditional chemotherapy groups. The new chemotherapy group received neoadjuvant chemotherapy of Tezio combined with Apatinib before surgery, and the control group received the traditional first-line chemotherapy regimen of oxaliplatin combined with capecitabine. During the chemotherapy, the adverse complications of the two groups of patients were recorded, and the RECIST1.1 evaluation system was used to evaluate the chemotherapy effect of the patients after chemotherapy. At the same time, the R0 resection rate of the two groups of patients with gastric cancer radical surgery was recorded and compared. The fasting venous blood of the patients was collected before the chemotherapy, after the end of chemotherapy, and one week after the operation. The content of immunoglobulin G and M (IgG and IgM) was measured. The flow cytometry was used to detect CD4 + T cells and CD8+ T cells. A total of 64 patients were enrolled in this study, including 26 patients in the new chemotherapy group. Chi-square test showed that the incidence of bone marrow suppression (Leukopenia, thrombocytopenia and anemia) and liver dysfunction in the new chemotherapy group were lower than that in the traditional chemotherapy group (all P <0.05), but the surgical R0 resection rate in the new chemotherapy group was higher than that in the traditional chemotherapy group (P <0.05). Wilcoxon rank-sum test and chi-square test found that the chemotherapy effect of the new chemotherapy group was better than that of the traditional chemotherapy group, and the results of repeated measures analysis of variance showed that the IgG, IgM and CD4+/CD8+ T cell ratios of the patients in the new chemotherapy group were higher than that of traditional chemotherapy group (all P <0.05). Apatinib combined with Tezio's preoperative neoadjuvant chemotherapy can improve the chemotherapy effect of advanced gastric cancer, increase the rate of surgical R0 resection, and reduce the patient's immunosuppressive status during treatment.
Comparison of diagnostic efficacy of MRI and PET/CT in lung cancer of mouse with spinal metastasis
Authors: Hu Wenkai , Liu Zheng , Xiao Xiao , Yang Yan , Sun Zhicheng , Wang Xiyang
Published: June 2020

This study aimed to compare the diagnostic efficacy of MRI and PET/CT in lung cancer of mouse with spinal metastasis. 40 healthy Balb/c nude mice were selected. 0.1 ml of human lung cancer cell A549 bacterial suspension was injected by the left ventricle injection method to establish a lung cancer spinal metastasis model, and the abnormal signs of the nude mice were closely observed. When the body weight was reduced by 20%, micro PET/CT imaging and small coil MRI imaging were applied after intraperitoneal injection of thiopental anesthesia in nude mice. After the imaging was completed, the nude mouse was dissected and the spinal tumor was removed. The nature of spinal metastases was diagnosed by the pathology department. 5 nude mice died of abdominal infection, 2 nude mice had no spinal tumors, and the remaining 33 nude mice were successfully modeled. 33 nude mice were confirmed by pathology to have 64 metastatic vertebral lesions, among them, there were 7 cervical vertebrae, 24 thoracic vertebrae, 16 lumbar vertebrae, 6 sacral vertebrae and 11 caudal vertebrae. The sensitivity of MRI in the diagnosis of spinal metastases was 78.13%, and specificity was 56.25%. The sensitivity of PET/CT for the diagnosis of spinal metastases was 92.19%, and specificity was 78.95%. The specificity and positive predictive value of PET/CT for the diagnosis of spinal metastases were not significantly different from those of MRI (P> 0.05). The sensitivity, accuracy and negative predictive values were significantly higher than those of MRI (P< 0.05). PET/CT is superior to MRI in the diagnosis of spinal metastases, and its sensitivity, accuracy and negative predictive values were significantly higher than those of MRI (P< 0.05). It is worthy to be further promoted in clinical practice.
Analgesic action of Rubimaillin in vitro and in vivo
Authors: Yan Wanli , Jiang Zhonglei , Fan Fengyun
Published: June 2020

Pain, a common symptom in clinics, is a serious impediment to quality of life. The analgesic drugs presently in use have poor efficacy, and are associated with undesirable side effects. Rubimaillin (Rub) is a naphthoquinone compound extracted from Chinese herbal medicine, and it has various biological activities. In this study, the analgesic effect of Rub, and its mechanism of action were investigated using glacial acetic acid-induced mice writhing model and a mice model of neurogenic and inflammatory bipolar pain. Analgesic effects were measured in different experimental groups. In vitro, RAW 264.7 cells were used to investigate the release of nitric oxide (NO), iNOS and COX-2 protein in RAW 264.7 cells stimulated with lipopolysaccharide (LPS). The results revealed that Rub reduced the number of acetic acid-induced writhing in mice, inhibited formalin-induced biphasic pain response, and suppressed the production of NO in RAW 264.7 cells. The mechanisms involved in the analgesic and anti-inflammatory effects of rub may be related to the inhibition of cyclooxygenase-2 (COX-2), endogenous inflammatory mediators, and reduction in the content of pain-induced mediators.
The expression and significance of NF-ÎºB, MMP1, and MMP2 in rats with abdominal aortic aneurysm
Authors: Xie Zhilei , Fang Tao
Published: June 2020

This study aimed to investigate the expression and significance of NF-ÎºB, matrix metal protein1 (MMP1), and matrix metal protein2 (MMP2) in rats with abdominal aortic aneurysm (AAA). 48 Wistar rats were collected, then they were divided into an experiment group and a control group (n=24). The rats in the experiment group were used to carry out an abdominal aortic aneurysm modeling, while the rats in the control group were infused with a same dose of saline through catheters. qRT-PCR and ELISA were used to detect the expressions of EGF and VEGF-C in skin tissues and mRNA of NF-ÎºB, MMP1, and MMP2 in their abdominal aorta. A vernier caliper was used to measure the diameter of their abdominal aorta. Western blot was used to detect the expressions of NF-ÎºB, MMP1, and MMP2 in their abdominal aorta. In the experiment group, the abdominal aorta of the rats expanded to some extent after they were infused compared to that before they were infused (P< 0.05), and the abdominal aorta of them was significantly larger than that of the rats in the control group. On the 3rd week after modeling, the abdominal aorta of the rats expanded more obviously compared to that after they were infused for a while in the experiment group, and the expansion rate of the diameter was (57.19 ± 4.67)% (P< 0.05). Protein expression levels of NF-ÎºB, MMP1, and MMP2 in the abdominal aorta of the rats increased significantly in the experiment group compared to those of the rats in the control group (P<0.05). The increase of NF-ÎºB, MMP1, and MMP2 may be related to the pathogenesis of abdominal aortic aneurysm in abdominal aortic aneurysm models of rats.
Effect of lncRNA KCNQ1OT1 on autophagy and drug resistance of hepatocellular carcinoma cells by targeting miR-338-3p
Authors: Zhong Weiwei , Dai Qianqian , Huang Qionghui
Published: June 2020

The current experiment aimed to investigate the effects of lncRNA KCNQ1OT1 on the proliferation, autophagy and drug resistance of hepatocellular carcinoma cells, as well as the potential molecular mechanism. Hepatocellular carcinoma SK-HEP-1 cells and DDP resistant SK-HEP-1/DDP cells were treated with cisplatin (DDP) of different concentrations (1 nmol/L, 2 nmol/L, 4 nmol/L, 8 nmol/L, 16 nmol/L). The survival rate of SK-HEP-1 and SK-HEP-1/DDP cells was determined by the CCK8 method. QRT-PCR was used to detect the levels of lncRNA KCNQ1OT1 and miR-338-3p in normal hepatocyte HH01, hepatocellular cell SK-HEP-1 and hepatoma cisplatin-resistant cell SK-HEP-1/DDP. Western blot was carried out to detect the expression levels of autophagy-related protein Beclin1 and proliferation-related protein P21 in cells. A dual-luciferase reporter assay system was performed to validate the relationship between KCNQ1OT1 and miR-338-3p. After the treatment of 1 nmol/L, 2 nmol/L, 4nmol/L, 8nmol/L and 16nmol/L cisplatin (DDP), the survival rate of SK-HEP-1/DDP cells is higher than that of SK-HEP-1 cells. The level of lncRNA KCNQ1OT1 was increased successively in HH01, SK-HEP-1 and SK-HEP-1/DDP cells, while miR-338-3p was decreased successively. Silencing lncRNA KCNQ1OT1 or over-expressing miR-338-3p combined with 16nmol/L DDP treatment reduced the survival rate of SK-HEP-1/DDP cells and up-regulate levels of P21 and Beclin1 proteins. LncRNA KCNQ1OT1 targeted and negatively regulated the expression of miR-338-3p. Inhibition of miR-338-3p reversed the effect of silencing lncRNA KCNQ1OT1 on survival, autophagy and cisplatin sensitivity of SK-HEP-1/DDP cell. LncRNA KCNQ1OT1 targets miR-338-3p to regulate the survival rate and autophagy of SK-HEP-1/DDP cells and improve the cisplatin sensitivity of SK-HEP-1/DDP cells.  LncRNA KCNQ1OT1 is a potential molecular target for hepatocellular carcinoma.
Construction of SIRT1 gene shRNA lentivirus vector and its effect on the proliferation of breast cancer cells
Authors: Yue Yanbo , He Lili , Tian Mi , Li Xin
Published: June 2020

Current experiment aimed to investigate the construction of the SIRT1 gene shRNA lentivirus vector and its effect on proliferation of breast cancer cells. Altogether 80 cases of breast cancer tissues and 80 cases of normal adjacent tissues were collected. qPCR was used for detecting SIRT1 expression. Western blot was used to detect the expression of EMT marker protein. The effect of lentivirus infected sh-SIRT1 on the cell biological function of SK-BR-3 and MDA-MB-231 cells was detected. MTT assay was used to detect cell activity, Transwell cell was used to detect cell invasion and migration, and cell apoptosis detected by flow cytometry. Compared with normal tissues adjacent to cancer, the expression of SIRT1 in cancer tissues increased significantly. Compared with human breast epithelial cells (MCF 10A), SIRT1 expression in breast cancer cells (MDA-MB-231, SK-BR-3) increased significantly. The above results showed that SIRT1 was significant greatly expressed in breast cancer. Compared with the sh-Control group, the cell activity, invasion and migration of the sh-SIRT1 group were enhanced, while cell apoptosis was weakened. In the sh-SIRT1 group infected by lentivirus, cell activity, cell invasion and migration decreased, while cell apoptosis increased. Compared with sh-Control, the expression of Î±-catenin, PTEN and E-cadherin in the sh-SIRT1 group in SK-BR-3 and MDA-MB-231 cells was down-regulated, while the expression of N- cadherin, Î²-catenin and Vimentin was up-regulated. Compared with sh-Control, the expression of Î±-catenin, PTEN and E-cadherin in the sh-SIRT1 group infected by lentivirus was up-regulated, while the expression of N- cadherin, Î²-catenin and Vimentin was down-regulated. To sum up, SIRT1 is highly expressed in breast cancer cells. The proliferation of breast cancer cells was inhibited after lentivirus infection with sh-SIRT1.
Combating sars-cov-2 through lipoxins, proteasome, caveolin and nuclear factor-Îºb pathways in non-pregnant and pregnant populations
Authors: Celik Onder , Celik Nilufer , Aydin Suleyman , Baysal Bora , Aydin Suna , Saglam Aylin , Gursu Yagmur , Dalkilic Semih , Ulas Mustafa , Ozcil Mustafa D , Tayyar Ahter T , Cengiz Ferhat , Ugur Kader , Akkoc Ramazan Fazil , Ersahin Aynur A
Published: June 2020

It can be misleading to think that the new severe acute respiratory syndrome coronavirus (SARS-CoV2) which has a very strong mutation and adaptation capabilities, uses only the angiotensin-converting enzyme II (ACE2) pathway to reach target cells. Despite all the precautions taken, the pandemic attack continues and the rapid increase in the number of deaths suggest that this virus has entered the cell through different pathways and caused damage through different mechanisms. The main reason why the ACE2 pathway comes to the fore in all scientific studies is that this receptor is located at the entry point of basic mechanisms that provide alveolo-capillary homeostasis. SARS-CoV-2 has to use nuclear factor-ÎºB (NF-kB), caveloae, clathrin, lipoxin, serine protease and proteasome pathways in addition to ACE2 to enter the target cell and initiate damage. For this reason, while new drug development studies are continuing, in order to be beneficial to patients in their acute period, it is imperative that we are able to come up with drugs that activate or inhibit these pathways and are currently in clinical use. It is also critical that we adopt these new pathways to the treatment of pregnant women affected by SARS-CoV-2, based on the scientific data we use to treat the general population.
The Gender-bias Effect of Test Scoring and Framing: A Concern for Personnel Selection and College Admission
Authors: Espinosa Maria Paz , Gardeazabal Javier
Published: June 2020

This paper analyzes gender differences in student performance in Multiple-Choice Tests (MCT). We report evidence from a field experiment suggesting that, when MCT use a correction for guessing formula to obtain test scores, on average women tend to omit more items, get less correct answers and lower grades than men. We find that the gender difference in average test scores is concentrated at the upper tail of the distribution of scores. In addition, gender differences strongly depend on the framing of the scoring rule.
Electronic structural properties of amino/hydroxyl functionalized imidazolium-based bromide ionic liquids
Authors: Hu Xiaoling , Jia Xingang , Su Kehe , Gu Xuefan
Published: June 2020

Electronic structural properties of the three different imidazolium-based ionic liquids, namely, 1-butyl-3-methyl imidazolium bromide (C4mimBr), 1-(4-hydroxybutyl)-3-methylimidazolium bromide (C4OHmimBr), and 1-(4-aminobutyl)-3-methylimidazolium bromide (C4NH2mimBr), were investigated with density functional theory at the B3LYP/6-311++G(d,p) level. The conformations of the mentioned cations were fully studied first using CONFLEX 8.A program. The quantum theory of atoms in molecules was used to investigate the nature of intramolecular interactions. The counterpoise-corrected ion pairs binding energies were obtained at the same level of theory. Natural bond orbital analyses show that the largest intra-molecular interaction comes from the orbital overlap between n(N1) and π* (N4–C5) in the mentioned compounds. The energy levels of frontier molecular orbitals (FMOs) are displayed. The global quantum chemical descriptors are also calculated based on the energy values of FMOs.