bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of virtual teaching of diagnostic and interventional imaging fundamentals to Egyptian medical students: an analytical cross-sectional study
Authors: Negm Ahmed S. , Elhatw Ahmed , Badawy Mohamed , Gioe Meredith L. , Khan Sana , Hammad Mahmoud F. , Shalaby Nada , Choucair Ferial , Saad Mariam Ahmed , Elfeel Amany , Elbatal Mariam , Saenz Florentino , Shehata Mostafa Ahmed , Patel Parth , Aly Muhammad , Khalifa Islam , Kamel Serageldin , ElHefnawi Yara , Fahmy Mohamed Ismael , Rohren Scott , Hussein Mohamed Yasser , Elsaiey Ahmed , Zitoun Owiss , Elsayes Khaled M.
Published: January 2022

Background

There is a worldwide deficit in teaching and training in the field of radiology for undergraduate medical students. This educational gap is prominent in many medical schools as most radiology curricula are a part of other specialty trainings, usually provided by non-radiologists. After COVID-19 pandemic, there was an increased trend in online education. However, questions have been raised about the efficacy and acceptance of online education. We developed a course on the principles of radiology and medical imaging basics to target Egyptian medical students. We then assessed the impact of these educational videos through several online surveys. Our "The Principles of Radiology Online Course" was delivered to students at various Egyptian medical schools; it was a prerecorded series composed of nine sessions, and each session followed the sequence of a pre-test, video, and post-test. There was a final survey to assess the overall feedback. Finally, we analyzed the results to give insight onto how teaching radiology through online lectures can help build better physicians.

Results

Among various medical schools around Egypt, 1396 Egyptian medical students joined this cohort. Cohort population percentage was 56% female and 44% male. Ninety-eight percent of the students agreed that this program increased their understanding of radiology. Eighty-four percent of the students found the platform friendly and easy to use. Seventy-nine percent found these webinars were more convenient compared to in-person education. Statistical significance (p-value < 0.05) was achieved in all sessions after comparing students’ pre and post-test scores, and in students’ confidence and knowledge level before and after the course.

Conclusions

Radiology is an underrepresented subject for a lot of medical students. Online radiology webinars have proven to be a promising method of teaching medical students key medical imaging concepts. An online course of radiology basics and principles can help improve a medical student’s knowledge and enhance overall future patient care.
A large and invasive pleomorphic adenoma of nasal cavity: a rare case report and review of literatures
Authors: Cherrabi Kaoutar , Maqboub Omar , Benmansour Najib , El Alami Mohamed Noureddine
Published: January 2022

Background

Pleomorphic adenomas are common tumors of major salivary glands. However, the localization in nasal cavity originating from the lateral wall is exceptional.

This work is a presentation of a very rare case that presents the diagnostic challenge, considering the multitude of malignant and benign differential diagnosis. A discussion of surgical approach, and the possible complications associated with it.

Case presentation

This is the case of an invasive nasal pleomorphic adenoma in a 48-year-old patient; the patient underwent complete excision through combined left lateral rhinotomy and functional endoscopic sinus surgery.

Conclusion

Pleomorphic adenoma is a very rare benign tumor of the nasal cavity. Clinical diagnosis is generally difficult regarding the multitude of differential diagnosis. Confirmation is established upon histological aspect.

This is a case of a very rare large pleomorphic adenoma of nasal cavity originating from the lateral wall, associated with differential diagnosis, and surgical approaches, as well as perceivable complications.

The strength of this work is to point out the importance of complete surgical extirpation and thorough follow-up to prevent recurrences and malignant transformation.
Low-level laser therapy for treatment of tinnitus in Red Sea scuba divers: a randomized clinical study
Authors: Elsayad Osama A. , Alsharif Basel
Published: January 2022

Background

Scuba diving has become a popular hobby. However, diving puts the auditory system at the risk of a wide variety of complaints including tinnitus. Low-level laser therapy is a new modality in treatment of tinnitus. This study evaluates effect of laser therapy on tinnitus of scuba divers in Red Sea. This randomized study included 200 scuba diving patients with tinnitus without any other audiological symptoms. They were randomly divided into two groups: GI (n=100) patients were subjected to 60 sessions of laser therapy, and in the other group GII (n=100), the machine was off while doing the procedure. The Tinnitus Questionnaire (TQ) was done every 20 days to evaluate the severity of the tinnitus for both groups.

Results

Both groups were matched regarding age and sex distribution. GI group experienced significantly decreased tinnitus severity compared to GII after laser therapy. There was no relation between duration of diving and laser therapy effect in GI.

Conclusion

Laser therapy is effective in treatment of tinnitus of scuba divers and its effect is increased by number of laser sessions.
Did we learn something positive out of the COVID-19 pandemic? Post-traumatic growth and mental health in the general population
Authors: Menculini Giulia , Albert Umberto , Bianchini Valeria , Carmassi Claudia , Carrà Giuseppe , Cirulli Francesca , Dell’Osso Bernardo , Fabrazzo Michele , Perris Francesco , Sampogna Gaia , Nanni Maria Giulia , Pompili Maurizio , Sani Gabriele , Volpe Umberto , Tortorella Alfonso
Published: January 2022

Background

When facing a traumatic event, some people may experience positive changes, defined as posttraumatic growth (PTG).

Methods

Understanding the possible positive consequences of the pandemic on the individual level is crucial for the development of supportive psychosocial interventions. The present paper aims to: 1) evaluate the levels of PTG in the general population; 2) to identify predictors of each dimension of post-traumatic growth.

Results

The majority of the sample (67%, N = 13,889) did not report any significant improvement in any domain of PTG. Participants reported the highest levels of growth in the dimension of “appreciation of life” (2.3 ± 1.4), while the lowest level was found in the “spiritual change” (1.2 ± 1.2). Female participants reported a slightly higher level of PTG in areas of personal strength (p < .002) and appreciation for life (p < .007) compared to male participants, while no significant association was found with age. At the multivariate regression models, weighted for the propensity score, only the initial week of lockdown (between 9-15 April) had a negative impact on the dimension of “relating to others” (B = −.107, 95% CI = −.181 to −.032, p < .005), while over time no other effects were found. The duration of exposure to lockdown measures did not influence the other dimensions of PTG.

Conclusions

The assessment of the levels of PTG is of great importance for the development of ad hoc supportive psychosocial interventions. From a public health perspective, the identification of protective factors is crucial for developing ad-hoc tailored interventions and for preventing the development of full-blown mental disorders in large scale.
A thermodynamic origin for the Cohen-Kaplan-Nelson bound
Authors: Ramakrishna Satish
Published: January 2022

The Cohen-Kaplan-Nelson bound is imposed on the grounds of logical consistency (with classical General Relativity) upon local quantum field theories. This paper puts the bound into the context of a thermodynamic principle applicable to a field with a particular equation of state in an expanding universe. This is achieved without overtly appealing to either a decreasing density of states or a minimum coupling requirement, though they might still be consistent with the results described. We do so by defining an appropriate Helmholtz free energy which when extremized relative to a key parameter (the Hubble radius L) provides a scaling formula for the entropy with the Hubble radius (an exponent r used in the text). We deduce that the CKN bound is one possible solution to this extremization problem (with

), but there are others consistent with r = 2. The paper establishes that the holographic principle applied to cosmology is consistent with minimizing the free energy of the universe in the canonical ensemble, upon the assumption that the ultraviolet cutoff is a function of the causal horizon scale.
Divergent evolution of developmental timing in the neocortex revealed by marsupial and eutherian transcriptomes
Authors: Kozulin Peter , Suárez Rodrigo , Zhao Qiong-Yi , Paolino Annalisa , Richards Linda J. , Fenlon Laura R.
Published: January 2022

Only mammals evolved a neocortex, which integrates sensory-motor and cognitive functions. Significant diversifications in the cellular composition and connectivity of the neocortex occurred between the two main therian groups: marsupials and eutherians. However, the developmental mechanisms underlying these diversifications are largely unknown. Here, we compared the neocortical transcriptomes of Sminthopsis crassicaudata, a mouse-sized marsupial, with those of eutherian mice at two developmentally equivalent time points corresponding to deeper and upper layer neuron generation. Enrichment analyses revealed more mature gene networks in marsupials at the early stage, which reverted at the later stage, suggesting a more precocious but protracted neuronal maturation program relative to birth timing of cortical layers. We ranked genes expressed in different species and identified important differences in gene expression rankings between species. For example, genes known to be enriched in upper-layer cortical projection neuron subtypes, such as Cux1, Lhx2 and Satb2, likely relate to corpus callosum emergence in eutherians. These results show molecular heterochronies of neocortical development in Theria, and highlight changes in gene expression and cell type composition that may underlie neocortical evolution and diversification.

This article has an associated ‘The people behind the papers’ interview.
A multimodality review of male urethral imaging: pearls and pitfalls with an update on urethral stricture treatment
Authors: Revels Jonathan Wesley , Wang Sherry S , Weaver Jennifer S , Foreman Jordan R , Gallegos Maxx A , Thompson William M , Katz Douglas , Moshiri Mariam
Published: January 2022

Optimum radiological assessment of the male urethra requires knowledge of the normal urethral anatomy and ideal imaging techniques based on the specific clinical scenario. Retrograde urethrography is the workhorse examination for male urethral imaging, usually utilized as the initial, and often solitary, modality of choice not only in the setting of trauma, but also in the pre- and post-operative evaluation of urethral strictures. There is, however, growing interest in utilization of ultrasound and magnetic resonance for evaluation of the male urethra owing to lack of ionizing radiation and improved delineation of the adjacent tissue. We review the various modalities utilized for imaging of the male urethra for a variety of known or suspected disorders, and provide an update on current treatments of urethral strictures. Additionally, we detail the key information needed by urologists to guide management of urethral strictures. We conclude with a brief discussion of neophallus urethral diseases following female-to-male sexual confirmation surgery.
ANÁLISE DE ESTRATÉGIAS EM GESTÃO DE ESTOQUE E DE DEMANDA POR MEIO DE POSSÍVEIS CENÁRIOS: PROPOSTA DE UM MODELO MENTAL EM SIMULAÇÃO ARENA ®
Authors: Morais Roberto Ramos de , Moori Roberto Giro , Gardesani Roberto
Published: January 2022

O objetivo deste estudo foi explorar a importância dos conhecimentos teóricos e práticos para o desenvolvimento de um modelo para gestão de estoque e sua simulação. Utilizando-se do aplicativo ARENA ®, foram gerados conhecimentos para serem direcionados para aplicação em operações empresariais. Com os resultados, concluiu-se de um lado, na modelagem, que foi essencial conhecer teorias que deram sustentação para descrever os limites e os comportamentos do sistema por meio de parâmetros de entrada; de outro, as análises podem ser difíceis de interpretação como relações de causa-efeito, especialmente, em descobrir se os resultados foram efeitos das inter-relações entre as variáveis ou da aleatoriedade do sistema modelado.
The Trials and Tribulations of the National Health System (ESY) in Greece: A Chronicle of Unfulfilled Promises
Authors: Philalithis Anastas
Published: January 2022

The creation of the National Health System (ESY) in the 1980s is a majorlandmark in the development of the welfare state in Greece during the metapolitefsi (regime change) period. An ambitious effort to reform the fragmented, ineffective health services of the post-World War II period, it achieved a major reorganisation of public hospitals and the establishment of rural health centres providing primary health care. Yet its promise of high-quality services for all was not fulfilled, since vested interests blocked its full implementation. While the fiscal crisis of the 2010s was the catalyst for theunification of the health insurance funds, the creation of integrated primary health care intowns failed once again. This article examines the achievements and failures of the reform in light of the political and social factors that shaped this era.
Enhancing innovative delivery in schools using design thinking
Authors: Gopinathan Sharmini , Kaur Anisha Haveena , Ramasamy Kanesaraj , Raman Murali
Published: January 2022

The pandemic has created challenges in all sectors of the economy and education. Traditional teaching approaches seem futile in the new context, thus the need to constantly reinvent the delivery to meet the fast-paced changes in the education domain. Hence, Design Thinking (DT) is an alternative approach that might be useful in the given context. DT is known to be a human-centric approach to innovative problem-solving processes. DT could be employed in the delivery process to develop twenty-first-century skills and enhance creativity and innovation, in an attempt to identify alternative solutions. The study explores the role of design thinking (DT) in the form of empathy, thinking process, gamified lessons and curriculum enhancement, which leads to innovative delivery among teachers. It enhances and facilitates innovative content delivery by leveraging creativity. The study targeted 131 teachers, whereby 61 are primary school teachers and 70 are secondary school teachers. A questionnaire constituting of 23 close-ended questions using the 5-point Likert scale was used to collect data. Data was analyzed using SmartPLS to establish relationships between DT and Innovative Delivery in schools. The data was further analyzed to seek co-relations between the DT steps and the successful transformation of content delivery by teachers. The study established a framework for the application of design thinking for teachers as the primary support in developing activities for their students. It shows that thinking process, gamifying lessons and curriculum enhancement have positive significance in innovative delivery, whereas empathy did not show a significant positive relationship. The outcome of this study will help fill the gap towards creating an interesting method of delivery in schools and constantly innovating the method to suit the evolving generation. This insight is crucial for the Ministry of Education and policymakers to enhance teachers’ ability to innovatively deliver content to students.
Case Report: Stem cell therapy in amyotrophic lateral sclerosis
Authors: Hassan Ala'a A. , Elkins Jeananne , Hassan Hisham Y.
Published: January 2022

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease leading to loss of upper and lower motor neurons at both spinal and bulbar levels.   For patients with ALS rehabilitation is important to maintain functional independence, ensure safety and optimize quality of life but is not curative. Stem cell therapy (SCT) provides a new approach to treat previously incurable diseases although peer reviewed published evidence has shown no benefit in ALS for slowing disease progression or functional loss.  

This case report presents a patient with ALS who underwent SCT but deteriorated rapidly after the procedure. Whether the deterioration was due to the natural progress of the disease or expedited by SCT remains unknown. The ethical considerations of how marketing influences healthcare and individuals’ decisions in desperate situations along with reasons for taking desperate measures are discussed.  Patient education and open communication with ALS patients are imperative in gaining patient satisfaction and overcoming ill effects that marketing could have on unconventional methods of intervention. Raising awareness about the availability and access to multidisciplinary care, the timing of decisions with regards to symptom management and end of life care have proven to enhance the quality of life for such patients.
A narrative inquiry into the resettlement of armed forces personnel in the Arabian Gulf: a model for successful transition and positive mental well-being
Authors: Mottershead Richard , Alonaizi Nafi
Published: January 2022

Background: The study sought to explore the lived experiences of individuals having served in the Armed Forces of Saudi Arabia, as they made the transition to civilian life and sought new employment opportunities.    

Methods: Researchers carried out qualitative research in the form of narrative inquiry. Narratives were collected from eleven in-depth interviews conducted in Saudi Arabia in 2021, allowed for insight into participant experiences. Existing literature on military retirement was also investigated.

Results: Interviews were transcribed verbatim and analyzed concurrently using thematic analysis to identify patterns or themes. The researchers adopted thematic synthesis as an analytical framework though which descriptive themes from the literature on military retirement were generated. Overall, this approach allowed for the comparison of themes in literature with those of narrative interviews.

Conclusion: The study identified challenges encountered by veterans during the resettlement and transitional phase from military to civilian life. There was a general consensus, however, that military life equips individuals with valuable skills that are transferrable to successful post-military employment, known as Positive Transferable Adaptability for Employability (PTAE), (Mottershead, 2019), which can greatly empower those making the transition. These findings led the researchers to develop a new model for veteran career paths that meet the contemporary employment needs of the Kingdom of Saudi Arabia: the REVERE Transition Model, which identifies six career paths.
Intraneural glomus tumor within the digital nerve: a case report
Authors: Kim Sehun
Published: January 2022

A glomus tumor is a soft tissue tumor that arises from the glomus body, a peripheral organ responsible for regulating skin temperature. It accounts for about 1% to 5% of tumors occurring in the hand, is mainly located in the subungual region, and is less than 1 cm in size. The diagnosis is mainly based on clinical symptoms, and the main symptoms are pain at the site of the glomus tumor, pinpoint tenderness, and cold intolerance. The pain is severe and usually requires surgical resection, and the results of complete resection of the tumor are good. This case report presents a 37-year-old female patient who developed pain in the radial side around the proximal interphalangeal joint of the right second finger without any traumatic history. On physical examination and imaging, a glomus tumor of the digital nerve was diagnosed and resected. After surgery, the symptoms improved and there was no recurrence. A careful examination and accurate diagnosis and treatment are necessary for symptomatic masses.
Variation of the palmar cutaneous branch of the median nerve identified within the tendon sheath of the flexor carpal radialis
Authors: Park Ha Sung , Choi Shin Woo , Bae Joo-Yul
Published: January 2022

Purpose: During volar plate fixation of distal radius fractures, we have encountered patients with an anomalous course of the palmar cutaneous branch (PCB) of the median nerve within the sheath of the flexor carpi radialis (FCR) tendon. The purpose of this study was to assess the frequency and location of variations of the PCB within the sheath of the FCR tendon.Methods: This retrospective study enrolled 83 patients who underwent volar locking plate fixations through a modified Henry approach for distal radius fractures from July 2018 to April 2020. When we encountered an anomalous PCB within the sheath of the FCR tendon, we documented the specific finding and location where the PCB entered the sheath of the FCR tendon.Results: There were nine patients (10.8%) who had an anomalous course of PCB penetrating the sheath of the FCR tendon. The average entering point of PCB into the sheath of the FCR tendon was 3.07 cm from the distal wrist crease (range, 2.5–3.6 cm).Conclusion: An anomalous course of the PCB entering the sheath of the FCR tendon was observed at a high frequency (10.8%). Care must be taken not to injure the PCB during a dissecting of the FCR sheath during a modified Henry approach for a distal radius fracture.
Mechanical testing of paraosseous clamp-cerclage stabilization compared to interfragmentary wiring and combination technique in L-shape acrylic plate simulate to canine mandibular fracture
Authors:   Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart university, Bangkok 10900, Thailand, Thitiyanaporn Chaiyakorn , Wasanasuk Ketkaew ,   Surgery unit, Kasetsart University Veterinary Teaching Hospital Bangkhen, Kasetsart University, Bangkok 10900, Thailand, Shomwiwat Nessara ,   Sixth-year Veterinary Student, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, 10900, Thailand, Plangngan Prapaiporn ,   Sixth-year Veterinary Student, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, 10900, Thailand, Panmongkol Phavinee ,   Sixth-year Veterinary Student, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, 10900, Thailand, Suranunt Pawish ,   Sixth-year Veterinary Student, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, 10900, Thailand, Jaroensong Tassanee ,   Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart university, Bangkok 10900, Thailand
Published: January 2022

The purpose of this research was to comparison of the mechanical strength of the three different stabilization techniques in canine mandibular models. An L-shaped acrylic plate to replicate the mandible of a middle-sized dog was used as a canine mandibular fracture model. The research compared the strength of 3 fixation techniques: interfragmentary wiring, paraosseous clamp-cerclage stabilization, and a combination of both techniques. Each method was tested using 6 acrylic samples and measuring the maximum pressure load on the rostral mandible model using a Hounsfield H50KS testing machine. Statistical analysis was used to summarize the maximum load results from each method. The strengths of the interfragmentary wiring technique and the combination technique were not significantly different, while the paraosseous clamp-cerclage stabilization technique had significantly less strength than the other two techniques. The acrylic samples simulated the mandibular bone in a medium-sized breed dog because there are variable sizes and conformations of the mandible. This method was used to help neutralize other confounding factors associated with using real bone. In conclusion, the combination technique of interfragmentary wiring and paraosseous clamp-cerclage was the best method that can be used for increased stabilization of mandibular fixation. This technique was useful for facilitating stabilization of a mandible at a lower cost compared with the bone plate and screw method.
Visible-light metalens far-field nanofocusing effects with active
tuning of focus based on MIM subwavelength structures used in an
integrated imaging array
Authors: Meng Yang , Lyu Yan , Yu Zhongyuan , Chen Laurence Lujun , Liao Hongen
Published: January 2022

We propose a structure of a far-field nanofocusing metalens with focal
shifting that is actively tuned at visible wavelengths. Surface
plasmon polaritons (SPPs) can be excited by the metal-insulator-metal
(MIM) subwavelength structure at visible wavelengths. The coherent
interference of SPPs emitted by subwavelength nanostructures can form
a nanoscale focus. When the SPPs are excited and pass through several
concentric ring gratings with specific aspect ratios, the
extraordinary optical transmission phenomenon occurs. Two metal
concentric ring gratings achieve double diffraction, scattering light
to the far field. An anisotropic or isotropic electrically adjustable
refractive index material, such as liquid-crystal or optical phase
change material, is filled in a dielectric layer between two metal
layers, and the effective refractive index is modulated by
electronically controlled active tuning. The focal shift is achieved
by changing the effective refractive index of the intermediate
dielectric. In addition, different incident wavelengths correspond to
different effective refractive indices to achieve
time-division-multiplexing multi-wavelength achromatic focusing. The
finite-difference time-domain method was used to simulate the effect
of substrate effective refractive index variation on achromatic
superfocusing. The results show that the super-resolution focal spot (

F
W
H
M

=

0.158

λ
0

) with long focal length (

F
L

=

5.177

λ
0

) and large depth of field (

D
O
F

=

3.412

λ
0

) can be achieved by optimizing the
design parameters. The visible plasma metalens has potential
applications in high-density optical storage and optical microscopic
imaging, especially in three-dimensional display for light field and
integral imaging.
Incoherent range-based holography of far-distant objects using LIDAR
Authors: Hoffmann Mitchell P. , Dallmann Nicholas A. , Carlsten Bruce E. , Coblentz Malakai P. , Palmer David , Thompson David C.
Published: January 2022

Los Alamos National Laboratory has developed an incoherent, long-range,
sub-centimeter resolution (LIDAR) with which we achieve
centimeter-scale reflection holography at extremely long ranges. The
system consists of a pulsed laser and photon-counting receiver. This
combination yields round-trip time of flight data to illuminate parts
of the object of interest. The aggregation of these data for many
LIDAR pulses yields a plot with a range on the

X

axis and reflectance on the

Y

axis, which we refer to as a range
profile. Observing that the range profile is a projection of the
reflection map of the object onto the view vector, we collect profiles
from a variety of viewing angles and invert these data to form an
image. We adapt imaging algorithms from the field of computer aided
tomography to suit our application and present results from imaging
demonstrations at a 10 km range.
Terahertz beamforming network with a nonuniform contour
Authors: Hadei Milad , Dadashzadeh Gholamreza , Torabi Yalda , Lalbakhsh Ali
Published: January 2022

This paper presents a terahertz beamforming network based on a nonlocal lens with a 2D beam-scanning demonstration through leaky-wave antennas. The proposed design methodology is novel, to the best of our knowledge, in the aspect of using unconventional optimization parameters to significantly reduce the phase error associated with this class of beamformers. In this approach, a nonuniform contour defined by Fourier series expansion is used as a new optimization parameter to significantly decrease the phase error over a larger scan-angle than that in the previous works. The proposed system is a good candidate for industrial and security applications such as automotive radar sensors and electromagnetic THz imaging, thanks to its extensive 2D scanning range:

−

68

∘

to 0° in the elevation plane and

−

45

∘

to

+

45

∘

in the azimuth plane over the frequency range of 140–180 GHz.
Applicability of the Van Cittert–Zernike theorem in a Ronchi shearing interferometer
Authors: Liu Yang , Tang Feng , Wang Xiangzhao , Peng Changzhe , Li Peng
Published: January 2022

Ronchi shearing interferometry is a promising technique for in situ wavefront aberration measurement of the projection lens in advanced photolithography systems. The Van Cittert–Zernike theorem has been used to analyze the interference signal of a Ronchi shearing interferometer in the effective interference area (overlapping area of the

±
1

st diffraction orders produced by the image grating). However, the applicability of this theorem has not been systematically studied. In this work, the analytical expression of the Ronchigram in this area is derived based on the theory of scalar diffraction and incoherent imaging. The results show that only the object and image grating with infinite diffraction orders can fully satisfy the Van Cittert–Zernike theorem. In the finite diffraction orders case, the theorem can be considered approximately applicable in the overlapping area of the

±

3

rd diffraction orders produced by the image grating. The applicable area extends to the overlapping area of the

±
2

nd diffraction orders under a shear ratio of less than 1%, which accounts for 97% of the effective interference area. The theoretical analysis has been verified by simulation and fundamental experiments.
Orthogonally-polarized excitation for improved two-photon and second-harmonic-generation microscopy, applied to neurotransmitter imaging with GPCR-based sensors
Authors: Pulin Mauro , Stockhausen Kilian E. , Masseck Olivia A. , Kubitschke Martin , Busse Björn , Wiegert J. Simon , Oertner Thomas G.
Published: January 2022

Fluorescent proteins are excited by light that is polarized parallel to the dipole axis of the chromophore. In two-photon microscopy, polarized light is used for excitation. Here we reveal surprisingly strong polarization sensitivity in a class of genetically encoded, GPCR-based neurotransmitter sensors. In tubular structures such as dendrites, this effect led to a complete loss of membrane signal in dendrites running parallel to the polarization direction of the excitation beam. To reduce the sensitivity to dendritic orientation, we designed an optical device that generates interleaved pulse trains of orthogonal polarization. The passive device, which we inserted in the beam path of an existing two-photon microscope, removed the strong direction bias from fluorescence and second-harmonic (SHG) images. We conclude that for optical measurements of transmitter concentration with GPCR-based sensors, orthogonally polarized excitation is essential.
Doppler effect in the multiple-wavelength range-gated active imaging up to relativistic speeds
Authors: Matwyschuk Alexis
Published: January 2022

Having laid down previously the foundations of the combined multiple-wavelength range-gated active imaging (WRAI) principle recording a moving object in a four-dimensional space represented by a single image, it was necessary to know if a Doppler effect could appear in the direction of the radial velocity of the object. This is due to the fact that this imaging principle requires the emission of laser pulses at a certain frequency in relation to this speed. To know the limits, the radial velocity of the object was supposed to go up to relativistic speeds. From a theoretical approach, some temporal behaviors leading to the Doppler effect were shown. To validate this effect experimentally, a setup based on the fictional positions (represented by mirrors) of an object moving at extreme speeds was performed. The results obtained with WRAI confirmed the presence of the Doppler effect, which must be taken into account when the radial velocity of the object is extreme. In this case, some conditions must be met as in the period and the time of the shutter aperture. Singular behaviors have also been shown in the case of relativistic speeds. So despite the Doppler effect, the distance of the fast-moving object and the different moments are well identified according to the different wavelengths in the combined WRAI principle.
Performance and limitations of dual-comb based ranging systems
Authors: Martin Bruno , Feneyrou Patrick , Dolfi Daniel , Martin Aude
Published: January 2022

Dual-comb LiDARs have the potential to perform high-resolution ranging at high speed. Here, through an implementation involving electro-optic modulators and heterodyne detection, we quantify the ranging systems trade-off between precision and non-ambiguity range (NAR) using a unique performance factor. We highlight the influence of the comb amplitude envelope on the precision with a distance measurement limited by the repetition rate of the optical comb. The influence of the combs repetition rate on the NAR and on the precision is illustrated through a setup allowing distance measurement with a tunable NAR. Finally, we demonstrate the impossibility to resolve different targets, quantify the impact on the measured distance and develop on the conditions in which non-linear effects of the interference make the measurement impossible.
Near 100% external quantum efficiency 1550-nm broad spectrum photodetector
Authors: Shen Yang , Xue Xingjun , Jones Andrew H. , Peng Yiwei , Gao Junyi , Tzu Ta Ching , Konkol Matt , Campbell Joe C.
Published: January 2022

We report InGaAs/InP based p-i-n photodiodes with an external quantum efficiency (EQE) above 98% from 1510 nm to 1575 nm. For surface normal photodiodes with a diameter of 80 µm, the measured 3-dB bandwidth is 3 GHz. The saturation current is 30.5 mA, with an RF output power of 9.3 dBm at a bias of −17 V at 3 GHz.
Geometric control of next-nearest-neighbor coupling in evanescently coupled dielectric waveguides
Authors: Schulz J. , Jörg C. , von Freymann G.
Published: January 2022

We experimentally demonstrate that the next-nearest-neighbor-coupling
(NNN-coupling) in an array of waveguides can naturally be negative. To
do so, dielectric zig-zag shaped waveguide arrays are fabricated with
direct laser writing (DLW). By changing the angle of the zig-zag shape
it is possible to tune between positive and negative ratios of nearest
and next-nearest-neighbor coupling, which also allows to reduce the
impact of the NNN-coupling to zero at the correct respective angle. We
confirm the existence of negative NNN-couplings experimentally and
show the improved accuracy of a refined tight-binding model. Our
results are also of importance for other discrete systems in which the
tight-binding model is often used.
Restorable, enhanced, and multifaceted tunable optical properties in a coaxial quantum well driven by the electric field and intense laser field
Authors: Li Jingzhao , Li Keyin , Zhang Ge , Li Zhen , Chen Zhen Qiang
Published: January 2022

A new method for regulating optical properties of a coaxial cylindrical quantum well using the electric field and intense laser field is investigated in the effective mass approximation. By means of the finite difference method and the correct dressing effect of the confinement potential, the results show that the enhancement and recovery of optical absorption and refractive index change strongly depend on the multifaceted-cooperative regulation of the laser parameter, the electric field strength, the angle between the electric field and polarization direction of laser, and the barrier width. This is promising for the design of a new generation of highly polarization sensitive devices, optical repair equipments and optical phase modulators by adopting the multistage combination of electric and intense laser fields.
Aplanatic meniscus lens corrector for Ritchey-Chrétien telescopes
Authors: Rocha Michelle C. , Goncharov Alexander V.
Published: January 2022

An analytically designed aplanatic meniscus lens is proposed for increasing the field of view (FoV) of Ritchey-Chrétien (RC) telescopes. Compared to other field correctors, the proposed solution does not affect the initial RC telescope’s aplanatic properties, and it can be added or removed from an existing RC telescope without changing the mirrors’ shape. The final system features less astigmatism, which is balanced to flatten the image surface.
Fast physical random bit generation using a millimeter-wave white noise source
Authors: Guo Ya , Liu Wenjie , Huang Yimin , Sun Yuehui , Zinsou Romain , He Yixin , Zhang Ruonan
Published: January 2022

A broadband millimeter-wave (MMW) white noise signal generated by optical heterodyning of two Fabry-Perot laser diodes (FP-LDs) subject to optical feedback is demonstrated and employed for fast physical random bit generation with a simple least significant bits (LSBs) retaining method. Firstly, under suitable feedback conditions, two external-cavity feedback FP-LDs can be easily driven into chaotic states. In this process, the optical spectra of multi-longitudinal modes are significantly broadened. Then, two spectral broadening multi-longitudinal chaotic signals are mixed and converted into an MMW white noise signal through the heterodyne beating technique combined with a fast photodetector. With such an approach, a high dimensional broadband chaos with perfect characteristics of MMW white noise (3-dB bandwidth beyond 50 GHz without any time-delay signature) is experimentally achieved. Finally, taking the generated MMW white noise as the entropy source, 640 Gb/s physical random bit generation is realized by directly selecting 4-LSBs at 160 GS/s sampling rate after an 8-bit analog-digital-convertor.
Electrically tunable liquid crystal lens with a serpentine electrode design
Authors: Stevens Justin , Galstian Tigran
Published: January 2022

The design and operational principle of a new electrically tunable gradient index liquid crystal lens are described. The approach is based on linear serpentine electrodes and does not require a semiconductor layer. A preliminary validation is done for a lens with a 2 mm clear aperture, demonstrating 9.5 diopters of optical power and a root-mean-square wavefront error of 0.16 µm. The developed lens is tested with a miniature camera and the image quality improvement is demonstrated experimentally.
In-plane subwavelength optical capsule for lab-on-a-chip nano-tweezers
Authors: Minin Oleg V. , Chen Wei-Yu , Chien Shuo-Chih , Cheng Chia-Hsiung , Minin Igor V. , Liu Cheng-Yang
Published: January 2022

In this Letter, we propose a new, to the best of our knowledge, proof-of-concept of optical nano-tweezers based on a pair of dielectric rectangular structures that are capable of generating a finite-volume in-plane optical capsule. Finite-difference time-domain simulations of light spatial distributions and optical trapping forces of a gold nanoparticle immersed in water demonstrate the physical concept of an in-plane subwavelength optical capsule integrated with a microfluidic mesoscale device. It is shown that the refractive index of and the distance between the two dielectric rectangular structures can effectively control the shape and axial position of the optical capsule. Such an in-plane mesoscale structure provides a new path for manipulating absorbing nano-particles or bio-particles in a compact planar architecture, and should thus lead to promising perspectives in lab-on-a-chip domains.
Enhanced performance of an AlGaN-based deep ultraviolet light-emitting diode using a p+-GaN/SiO2/ITO tunnel junction
Authors: Che Jiamang , Shao Hua , Chu Chunshuang , Li Qingqing , Zhang Yonghui , Sun Xiaowei , Zhang Zi-Hui
Published: January 2022

In this work, a 280-nm-wavelength deep-ultraviolet light-emitting diode (DUV LED) with a p+-GaN/SiO2/ITO tunnel junction is fabricated and investigated. Due to the decreased tunnel region width and enhanced electric field intensity in the 1-nm-thick SiO2 layer, the interband tunneling efficiency and the corresponding hole injection efficiency are promoted. Therefore, the external quantum efficiency (EQE) for the proposed device is increased when compared with a traditional DUV LED. In addition, an improved current spreading effect is observed for our proposed device. As a result, improved wall-plug efficiency (WPE) is obtained owing to the increased optical power and decreased forward operating voltage. Meanwhile, the enhanced electric field intensity in the SiO2 layer reduces the voltage drop in the p-n junction region for the proposed device, and thus the leakage current is reduced.
Double-quantum–zero-quantum 2D coherent spectroscopy reveals quantum coherence between collective states in an atomic vapor
Authors: Yu ShaoGang , Geng YiFeng , Liang DanFu , Li HeBin , Liu XiaoJun
Published: January 2022

We report a novel, to the best of our knowledge, double-quantum–zero-quantum two-dimensional coherent spectroscopy (2DCS) that allows direct detection of the quantum coherence between multiparticle collective states. Through correlating the double-quantum coherence and the zero-quantum coherence, signatures for coherence between collective states can be well isolated as side peaks and readily identified in the 2D spectrum. The experiment is implemented in a vapor of rubidium atoms in a collinear 2DCS setup. Good agreement with a theoretical simulation using density matrix confirms the essential role of the interatomic correlation effect in generating the side peak signals. This 2D spectrum technique paves a new avenue for studying the coherent coupling of highly excited states and many-body properties.
Distributed high-temperature sensing based on optical frequency domain reflectometry with a standard single-mode fiber
Authors: Zhong Huajian , Fu Cailing , Li Pengfei , Du Bin , Du Chao , Meng Yanjie , Wang Yiping
Published: January 2022

Distributed temperature sensing up to 600°C at a fiber length of 100.75
m based on optical frequency domain reflectometry (OFDR) was
demonstrated using a standard single-mode fiber (SMF) without any
treatment. The spatial resolution was 2.5 mm. An algorithm,
instantaneous optical frequency resampling (IOFR), to eliminate the
nonlinearity of the laser source was proposed and used to obtain
calibrated reference and measurement signals that were used for
temperature demodulation. Moreover, the temperature response stability
of the annealed SMF was better than that of un-annealed SMF, where the
temperature sensitivity was 1.96 GHz/°C at 600°C.
Clinical presentations, diagnostics, treatments and treatment costs of children and adults with febrile illness in a tertiary referral hospital in south-eastern Guinea: A retrospective longitudinal cohort study
Authors: Raab Manuel , Pfadenhauer Lisa M. , Doumbouya Dansira , Froeschl Guenter
Published: January 2022

Background

Febrile illness is frequent among patients in the tropics. It is caused by a wide variety of common diseases such as malaria or gastrointestinal infections but also by less common but highly contagious pathogens with epidemic potential. This study describes the clinical features of adult and paediatric patients with febrile illness in in the largest tertiary referral hospital in south-eastern Guinea, a region at high risk for viral haemorrhagic fever outbreaks. The study further compares their diagnostic characteristics, treatments and outcomes with non-febrile patients in order to contribute to the local epidemiology of febrile illness.

Methods

We used retrospective data collection to record demographic and clinical data of all incoming patients during a study period of three months. For the follow-up study of inpatients, we retrospectively reviewed patient charts for diagnostic characteristics, diagnoses and outcomes.

Results

Of the 4317 incoming patients during the study period, 9.5% had a febrile illness. The most used diagnostic measures to identify causative agents in febrile patients were point-of-care tests and most treatments relied on antibiotics. Most common discharge diagnoses for febrile inpatients were malaria (9.6% adults, 56.7% children), salmonella gastroenteritis/typhoid (10.6% adults, 7.8% children) and respiratory infection/pneumonia (5.3% adults, 18.7% children). Inpatient mortality for children was significantly higher in febrile than non-febrile children (18.5% vs. 5.1%, p<0.001) and considerably higher in febrile than non-febrile adults (29.8% vs. 25.0%, p = 0.404).

Conclusions

Malaria, respiratory infection and gastroenteritis are considered the main causes for febrile illness. The wide reliance on rapid diagnostic tests to diagnose febrile patients not only risks to over- or under-diagnose certain diseases but also leaves the possibility of highly infectious diseases in febrile patients unexplored. Furthermore, the heavy reliance on antibiotics risks to cause antimicrobial resistance. High mortality rates in febrile patients, especially children, should be of concern to public health authorities.
Nuevos productos y servicios ofertados a las marcas por las principales cabeceras españolas: branded content y publicidad nativa
Authors: Zomeño Daniel , Blay-Arráez Rocío
Published: January 2022

Esta investigación analiza el contexto comunicativo nacido de la revolución digital y que ha llevado a las marcas a replantear parte de sus estrategias para llegar al consumidor de forma eficaz, dando prioridad a la creación de productos creativos de aspecto no publicitario, entre los que destaca la generación de contenidos. Los medios de comunicación se erigen como un partner estratégico para las marcas pasando de ser un espacio publicitario, a convertirse en consultor y proveedor de productos editoriales de valor añadido. El trabajo de campo de corte cualitativo ha tenido dos fases: entrevistas en profundidad a una muestra cualificada como son los responsables de branded content de los principales medios españoles y el análisis de contenido de sus sedes web, analizando los productos y servicios ofertados y cómo los definen. Los resultados se adentran en los departamentos y empresas de branded content de las principales cabeceras españolas que aportan una novedosa catalogación y descripción de los productos y servicios que están ofreciendo a las marcas y que les ha llevado a consolidar una relación inusual hasta la fecha. Estas conclusiones evidencian la transformación de los modelos de negocio de los medios y generan un conocimiento con posibilidades de transferencia.
Who leads the conversation? Influential Twitter users during a niche sporting event
Authors: Lamirán-Palomares José-María , Baviera-Puig Amparo , Baviera Tomás
Published: January 2022

Fans of niche sports generally find minimal content in mainstream media due to their limited audience. Instead, social media offers them the opportunity to follow these specific sports. The dynamics behind digital media are based on individual participation, hence some prominent users lead the social conversation thanks to their capacity to influence. However, the complexity of the concept of influence and the existence of multiple parameters for its measurement make it difficult to identify these key users. Our research proposes a measure of the influence on Twitter based on variables derived from the platform (number of tweets, number of retweets, and number of followers) and from the Social Network Analysis (outdegree, indegree, and PageRank). The Analytic Hierarchy Process was used to assign a weight to each variable. This measure of influence was applied to the conversation generated on Twitter around a niche sporting event: the 2018 UCI Track Cycling World Championships. From a 19 701-tweet corpus, we identified the 25 most influential users. The results indicate that the organisers and the participating cyclists played a relevant role in the Twitter conversation. In addition, the geographic distribution of these influential users reflects the cultural dependence of niche sports.