bluuebunny/crossref_metadata_2025 huggingface dataset:
Root Resorption: Simplifying Diagnosis and Improving Outcomes
Authors: Darcey James , Qualtrough Alison
Published: October 2020

Root resorption is a condition resulting in the progressive loss of dental hard tissue. It may occur both within the root and upon the external aspect of the root. Diagnosis can be difficult and management challenging. Understanding the pathology is critical to understanding why and when this disease occurs and what the best management techniques involve. With such knowledge practitioners can confidently diagnose resorption, discuss prognoses and management strategies with the patient and either refer or begin treatment. Early intervention is paramount in improving outcomes. As such, if practitioners choose to refer patients they must be aware of what can be done immediately to mitigate risks until consultation and specialist treatment begins.
An Overview of the Peer Assessment Rating (Par) Index for Primary Dental Care Practitioners
Authors: Green James Ij
Published: October 2020

The Peer Assessment Rating (PAR) index is a valid and reliable measure of orthodontic treatment outcome and is the most widely accepted such index.

Assessing outcomes with the PAR index requires the examination of pre-treatment and post-treatment orthodontic study models. Beginning with the pre-treatment models, a score is given to each feature that deviates from an ideal occlusion (all anatomical contact points adjacent, good interdigitation between posterior teeth and non-excessive overjet/overbite), the scores are then added together to give a total that represents the severity of the malocclusion. The process is then repeated with the post-treatment models. The difference between the pre-treatment and the post-treatment scores reflects the improvement that has taken place during treatment. A score of zero represents an ideal occlusion and in general the higher the score, the more extensive the malocclusion.

It is currently a condition of the NHS orthodontic contract for providers to monitor a proportion of their cases using the PAR index. This paper aims to provide primary dental care practitioners with an overview of the PAR index and should provide a useful guide for those wishing to seek calibration in the use of the index.
Clinical Dental Photography in Orthodontic Practice
Authors: Wander Philip
Published: October 2020

As with many aspects of clinical photography, the main purpose of dental photography is to help the dentist or clinician to monitor and document the patient's treatment. Standardisation is key in maintaining high quality clinical photography, and this article aims to help the photographer to produce the level of consistency and reproducibility needed in order to keep accurate clinical records, create treatment plans and prepare portfolios for orthodontic qualifications, such as a Master of Science (MSc) in orthodontics, or diplomas and awards in orthodontics for dental nurses and therapists.
The Role of Extended-Duties Orthodontic Nurses and Therapists in Delivering Oral Hygiene Instruction and Impression-Taking Clinics in a Specialist Orthodontic Practice
Authors: Rhodes Lucy
Published: October 2020

Provision of orthodontic care is increasingly the remit of a highly skilled and qualified team, led by a specialist orthodontist. Often separate patient clinics are held in specialist practice for oral hygiene instruction and for impression taking. These tasks are increasingly delivered, under prescription from the specialist orthodontist, by orthodontic nurses (ON) with appropriate post-registration training and/or orthodontic therapists (OT). Nurse or therapist-led clinics can be beneficial in stimulating patient co-operation, enhance both practice efficiency and staff involvement and maximise the patient experience.
Recognition, Intervention and Management of Digit Sucking: A Clinical Guide for the General Dental Practitioner
Authors: Kwon Ohsun , Haria Paras Jiteshkumar , Kotecha Sheena
Published: October 2020

Digit sucking is a common habit in young children, which if allowed to continue for a prolonged period, can adversely affect the development of the face and dental occlusion. Patients with digit sucking habits often present with an increased overjet, reduced overbite, anterior open bite, posterior crossbite and possible skeletal changes which can be challenging and costly to correct if the habit is not ceased in a timely manner. This article aims to provide guidance for general dental practitioners to recognise and appropriately manage patients with a digit sucking habit.
The Role of Mouthguards in Preventing and Reducing Sports-Related Trauma
Authors: Green James Ij
Published: October 2020

A mouthguard, also known as a gumshield, mouth protector or sports guard is an appliance that covers the teeth and surrounding mucosa with the aim of preventing or reducing trauma to the teeth, gingival tissue, lips and jaws. The device is usually worn on the maxillary arch and works by separating the maxillary and mandibular dentition, protecting the teeth from the surrounding soft tissue, absorbing or redistributing shock and/or stabilising the mandible during traumatic jaw closure. They may also play a role in preventing and reducing concussion by absorbing impact forces that would otherwise be transmitted through the base of the skull to the brain, although the evidence for this is less conclusive.

A mouthguard will usually fall into one of three categories: stock mouthguards (which are made ready to use and are believed to give the least protection), the mouth-formed or 'boil and bite’ type (which are heated in hot water, placed in the mouth and moulded to the teeth) and custom-made mouthguards (which are usually made on a stone model of the maxillary teeth and surrounding tissue and are thought to give the most protection).

These devices can be made from various materials but ethylene-vinyl acetate is by far the most popular material, probably because of the ease with which it can be used for the production of custom-made mouthguards.

This paper gives a review of the role of mouthguards in preventing and reducing sports-related trauma and examines the materials that are used to fabricate them.
The Emergency Treatment of Traumatised Permanent Anterior Teeth in Children and Adolescents
Authors: Mccann Catherine T , Welbury Richard R
Published: October 2020

This article aims to provide a practical clinician's guide to assessing and diagnosing dental trauma involving permanent teeth in children and young people, and for carrying out appropriate, guideline supported acute management. Timely referral to specialist paediatric dental services is crucial in more complex trauma presentations and will lead to improved outcomes for the dentition. Appropriate acute management by the primary clinician optimises the prognosis of any traumatised tooth and this article will focus on the emergency treatment of the traumatised permanent tooth.
Periodontal Emergencies in General Practice
Authors: Wadia Reena , Ide Mark
Published: October 2020

Diagnosing and managing periodontal emergencies is a common part of general dental practice. This article summarises the presentation, aetiology and management of the key periodontal emergencies, including gingival abscess, periodontal abscess, peri-coronitis/peri-coronal abscess, perio-endo lesion/abscess, necrotising gingivitis and periodontitis, acute herpetic gingivostomatitis, acute physical/chemical/thermal injury and subgingival root fracture.
The Emergency Dental Appointment: Restorative Emergencies Part 2 – Dental Implant Related Problems
Authors: Kalsi Harpoonam , Rodriguez Jose M , Darbar Ulpee , Bavisha Kalpesh
Published: October 2020

This is the second paper in a two-part series discussing the management of common restorative dental emergencies. The first paper focussed upon problems relating to conventional fixed and removable restorations, and this paper discusses the management of common dental implant related emergencies. With dental implant treatment becoming an increasingly popular method of replacing missing teeth, it is very likely that dentists working in general practice will routinely come across patients who have previously undergone this form of treatment, even if they themselves are not directly involved in placing or restoring dental implants. This paper is aimed at general dental practitioners (GDPs) who have some experience in managing dental implants, and those who want to gain further insight into how such situations may be managed.
Assessment and Management of Lumps on the Face: A Guide for the General Dental Practitioner
Authors: Cobb Richard , Dungarwalla Mohammed , Stenhouse Philip
Published: October 2020

There are a number of conditions that can present as a lump on the face. The general dental practitioner is uniquely trained in head and neck anatomy and pathology and should be able to identify these important conditions and consider appropriate investigations. Understanding what requires urgent specialist assessment and what can be referred routinely can be difficult, but is crucial to high quality patient outcomes.

This article aims to simplify common conditions that may present as a lump on the face or be an incidental finding within the primary dental care setting. It is by no means an exhaustive description of all the pathology that may be encountered within this anatomical region, however it should form a useful and practical framework for common presentations.
Tattoos of the Head, Neck and Hands
Authors: Wilson Nairn Hf , Wilson Hannah A , Wilson Margaret A
Published: October 2020

Tattooing is ancient and gaining popularity in present day society. While many tattoos are decorative body art, certain tattoos of the head, neck and hands may provide helpful insights into, among other traits, the personality, beliefs or orientation of an individual.
Denture Stomatitis: Causes, Cures and Prevention
Authors: Hannah Victoria Elizabeth , O'Donnell Lindsay , Robertson Douglas , Ramage Gordon
Published: October 2020

Removable dentures are worn by 20% of the UK population and two thirds of these individuals have denture stomatitis. Poor oral hygiene is commonplace among this group, as is smoking and xerostomia, which also contribute to the development of denture stomatitis. A complex polymicrobial biofilm is able to proliferate on the surface of denture materials and matures to form visible denture plaque. This denture plaque biofilm stimulates a local inflammatory process that is detectable clinically as erythema, and hyperplasia. Systemically, denture plaque represents a potential risk factor for systemic disease, in particular aspiration pneumonia. Respiratory pathogens have been detected in the denture plaque and overnight denture wear has been linked to an increased risk of aspiration pneumonia. There is a general lack of evidence on the adequate management of denture stomatitis and we present a protocol for use in the primary care setting.
Radiopacities of the Jaws: Interpretation and Diagnosis
Authors: Andrew David
Published: October 2020

General dental practitioners are less confident at diagnosing radiopaque lesions of the jaws than radiolucent ones, possibly because the incidence of jaw radiopacities is comparatively low. The current review covers the majority of radiopaque lesions that are referred for a specialist opinion, and focuses on those lesions that occur commonly or those that mimic other diagnoses. The majority of radiopaque jaw lesions represent normal anatomy/normal variants or superimposed soft tissue calcifications that are typically of no clinical significance. Common pathological radiopacities of the jaws include sclerosing (condensing) osteitis, a response to low-grade chronic apical infection, and odontomes, a form of odontogenic hamartoma. The typical imaging appearances of these and other jaw radiopacities are discussed.
Interocclusal Records in Fixed Prosthodontics
Authors: Thanabalan Naren , Amin Kiran , Butt Kasim , Bourne George
Published: October 2020

An accurate interocclusal record is essential for the successful delivery of fixed prosthodontic restorations. There are various materials and techniques used to obtain an interocclusal record in order to facilitate mounting of the dental casts on an articulator. The interocclusal record describes the vertical and horizontal relationship of the maxillary and mandibular teeth. In circumstances where the vertical relationship is not supported through a tripod of widely spaced opposing contacts, the interocclusal record will be needed to restore this vertical support to prevent inaccurate mounting. The clinician should understand when an interocclusal record is required and have an awareness of the different materials and techniques available to record an interocclusal registration.
Complex Dentistry in General Practice – What would you Do?
Authors: Eliyas Shiyana , Chana Pavneet , Briggs Peter
Published: October 2020

In 2019, in a world of instant gratification, what are the expectations of patients and dentists? Is training sufficient to meet these expectations? Decisionmaking in dentistry impacts the treatment choices patients are given, and may influence the outcomes of such treatment. It is therefore important to ensure as much standardisation as possible. In order to achieve this, it is important to know the current standard and the views of dentist as this will influence dental treatment planning.

Clinical Relevance

This paper captures the treatment planning dilemmas of dentists, specifically of those in their Foundation Training year, in order to aid targeting of training and development.

Objective Statement

To understand treatment decisions of general dental practitioners and specialists.
Evolution of Indirect Restorations for Fixed Prosthodontics: Planning, Preparation and Cementation
Authors: Patel Mahul
Published: October 2020

The provision of indirect restorations utilising contemporary materials for single or multiple abutment units in primary health care is an essential requirement for all general dental practitioners to ensure predictable patient outcomes. This paper highlights the important considerations for comprehensive planning and adept treatment execution and delivery that can enhance the patient's dental experience and outcome. A selection of clinical cases highlighting established and novel restorative materials utilising conventional and adhesive clinical techniques is presented and discussed.
The Updated Periodontal Classification: Answers to 10 Common Questions
Authors: Wadia Reena
Published: October 2020

In 2017, the World Workshop Classification system for periodontal and peri-implant diseases and conditions was developed. Thereafter, the British Society of Periodontology convened an implementation group to develop guidance on how the new classification system should be implemented in clinical practice in the UK. This paper covers answers to commonly asked questions on this new guidance.
An Update on the Links Beween Periodontal Health and General Health
Authors: Sharma Praveen
Published: October 2020

It should come as no surprise to the reader that the oral cavity, including the periodontal tissues, are not somehow disjointed from the rest of the body. In this paper, we will explore the links between the periodontal and general health of our patients in both directions. That is to say we will explore how someone's general or systemic health conditions/habits are likely to affect their periodontal health, and how someone's periodontal health is likely to affect their systemic health.

Before exploring these links, we will discuss the distinction between an association and a causal relationship, which is a subtle but vital distinction to make. We will then discuss the role of systemic conditions/habits such as diabetes, smoking, diet and stress on the periodontal health of individuals. Following from this, we will discuss the potential influence of the periodontal health of our patients on their systemic health, focussing on the more established links with diabetes and cardiovascular diseases as well as exploring the mechanisms by which these links may exist.

We will conclude with some tips on the holistic care of our patients, incorporating changes that will benefit their oral and systemic health.
Non-Surgical Periodontal Therapy - Evidence and Opinion
Authors: Ghuman Mandeep S.
Published: October 2020

Effective non-surgical periodontal therapy is fundamental to achieve and maintain periodontal health, particularly in individuals who are susceptible to periodontitis. This article aims to highlight current evidence and published guidance, together with personal insights and suggestions from the author's clinical experience to help with management of patients utilising this common treatment modality.
Crown Lengthening Surgery: An Overview
Authors: Kalsi Harpoonam Jeet , Bomfim Deborah I. , Hussain Zahra , Rodriguez Jose M. , Darbar Ulpee
Published: October 2020

The term ‘crown lengthening surgery’ refers to a variety of techniques which aim to expose a greater amount of tooth structure around a tooth or group of teeth. The decision to treat and which technique to use will depend upon: the underlying aetiology; a thorough history and examination; results of any supporting investigations and a clear understanding of the intended outcome of treatment. This paper aims to provide an overview of crown lengthening surgery and is illustrated with clinical cases.
Five new species of Ruellia (Acanthaceae) from the Atlantic Forest of northeastern Brazil
Authors:   Universidade Estadual de Feira de Santana, Chagas Earl , Costa-Lima James ,   Universidade Estadual de Feira de Santana
Published: October 2020

Five new species of Ruellia from the Atlantic Forest of northeastern Brazil are described: Ruellia curupira, R. fulozinha, R. insurrecta, R. jiboia, and R. taboleirana. Ruellia curupira (from the States of Alagoas and Bahia), R. fulozinha (Alagoas and Pernambuco), R. insurrecta (Alagoas), and R. jiboia (Alagoas and Bahia) occur exclusively in forested areas, whereas R. taboleirana is restricted to “Tabuleiros litorâneos” (Tabuleiro savanna) vegetation from Rio Grande do Norte to Alagoas. Due to the restricted distribution, resulting from high fragmented areas and the imminent threats, the five new species here proposed are provisionally considered under some degree of threat in accordance with the IUCN criteria. We provide morphological descriptions, comments on morphological affinities, data on habitat and distribution, as well as illustrations and photographs of living plants.
Voltammetric study of formic acid oxidation via active chlorine on IrO2/Ti and RuO2/Ti electrodes
Authors: Ollo Kambiré , Aliou Guillaume Pohan Lemeyonouin , Placide Sadia Sahi , Etienne Kouadio Kouakou , Lassiné Ouattara
Published: October 2020

This work aimed to contribute to the mechanism electrochemical oxidation study of organic compounds on DSA electrodes. To do this, IrO2 and RuO2 electrodes were prepared thermally at 40°C on Titanium substrate. The prepared electrodes were characterized using voltammetric and SEM techniques. The electrochemical measurements in acid media made it possible to show the presence of IrO2 and RuO2 on the surface of the electrode. These electrodes have identical electrocatalytic behaviors both for oxygen evolution and chlorine evolution. The prepared electrodes make it possible to oxidize the organic compounds in an acid media in the absence or in the presence of Cl-. In acidic electrolytes, water molecules produce hydroxyl radicals that contribute to the higher oxides (RuO3 or IrO3) formation. The higher oxides obtained produce O2 and regenerate the active sites of our electrodes. In the electrolytes containing chlorides, higher oxides fix them (IrO3(Cl) or RuO3(Cl)) in competition with the production of O2. Then IrO3(Cl) or RuO3(Cl) reacts with Cl- to produce Cl2 and regenerate the adsorbed hydroxyl radicals. The higher oxides also react as a mediator in HCOOH oxidation in competition with O2 evolvement. In the electrolytes containing HCOOH and Cl-, the organic pollutant's oxidation occurs indirectly via the hypochlorite ions produced in the solution and on the electrodes. This study showed that the produced OH· and Cl2 in situ are involved in the oxidation of HCOOH
Efficient and automated initial value estimation in digital image correlation for large displacement, rotation, and scaling
Authors: Fang Zheng , Gao Yue , Gao Zeren , Liu Yang , Wang Yaru , Su Yong , Zhang Qingchuan
Published: October 2020

The initial value estimation for seed point is the first step in digital image correlation calculation. Among the existing algorithms, the Fourier–Mellin transform-based cross correlation (FMT-CC) algorithm is one of the most efficient and robust owing to its rotation- and scale-invariance. However, when the displacement is large (more than a hundred pixels), the FMT-CC algorithm fails. In this paper, an automated and efficient initial value estimation method based on an FMT-CC algorithm is presented to deal with large displacement, large rotation, and large isotropic scaling. The relationship between subset size and the maximal displacement in the FMT-CC algorithm is studied, and a strategy of setting the subset size according to the estimated displacement is proposed to improve the robustness of the FMT-CC algorithm. In addition, in cases of large displacement, a multi-scale search method is proposed to improve efficiency. The experimental results show that the proposed methods can realize rapid and automated initial value estimation even under conditions of large displacement, large rotation, and large isotropic scaling. The computational efficiency of the multi-scale search method is about one order of magnitude higher than the traditional FMT-CC method.
Calibration of liquid crystal variable retarders using a common-path interferometer and fit of a closed-form expression for the retardance curve
Authors: Schnoor Nicholas P. , Niemeier Ryan C. , Woods Aaron L. , Rogers Jeremy D.
Published: October 2020

A liquid crystal variable retarder (LCVR) enables fast, automated
control of retardance that can be used as a variable waveplate in
polarimetric instruments. However, precise control of the polarization
state requires calibration of the LCVR. A manufacturer calibration
curve is typically supplied for a single specific wavelength and
temperature, but for applications under different conditions,
additional calibration is needed. Calibration is typically performed
with crossed polarizers to generate an intensity curve that is
converted to retardance, but this method is prone to noise when
retardance is close to zero. Here, we demonstrate a simple common-path
Sagnac interferometer to measure retardance and provide open source
software for automated generation of calibration curves for retardance
as a function of wavelength and voltage. We also provide a curve
fitting method and closed-form functional representation that outputs
the voltage needed to achieve a desired retardance given a specified
wavelength.
Ghost secondary light source for LED collimated illumination
Authors: Ohno Hiroshi
Published: October 2020

Collimated illumination using a light-emitting diode (LED) is widely
used in the residential, commercial, and optical inspection fields. A
typical collimator, namely, one that is a parabolic reflector, has a
focal point on which a light source should be placed. The light source
approximates a point source, which enables light rays reflected by the
reflector to form a collimated beam with a narrow light distribution
angle. However, it is difficult to place an LED at the focal point of
the reflector because a heat dissipator attached thermally to the LED
prevents the reflected light rays from emitting out. A curved light
guide that can generate a secondary light source at a focal point of
the reflector without disturbing reflected light, like a ghost, is
proposed here. A spotlight consisting of the curved light guide and a
parabolic reflector is fabricated and shows that a collimated beam
with a half-intensity angle of less than 4.3 deg can be realized with
the reflector opening diameter of 90.0 mm.
Optimized coded aperture for frugal hyperspectral image recovery using a dual-disperser system
Authors: Hemsley Elizabeth , Ardi Ibrahim , Lacroix Simon , Carfantan Hervé , Monmayrant Antoine
Published: October 2020

We present a novel acquisition scheme based on a dual-disperser architecture, which can reconstruct a hyperspectral datacube using many times fewer acquisitions than spectral bands. The reconstruction algorithm follows a quadratic regularization approach, based on the assumption that adjacent pixels in the scene share similar spectra, and, if they do not, this corresponds to an edge that is detectable on the panchromatic image. A digital micro-mirror device applies reconfigurable spectral–spatial filtering to the scene for each acquisition, and the filtering code is optimized considering the physical properties of the system. The algorithm is tested on simple multi-spectral scenes with 110 wavelength bands and is able to accurately reconstruct the hyperspectral datacube using only 10 acquisitions.
Polarization gradient cooling and trapping of charged and neutral microspheres
Authors: He Ziqiang , Dong Guangjiong
Published: October 2020

Laser cooling of macroscopic matters could pave the way for studying quantum-classic crossover and macroscopic quantum mechanics with potential application in quantum technologies. In this paper, we propose polarization gradient cooling and trapping of the microsphere in free space by exciting the degenerate whispering gallery modes using two counterpropagating optical fields with different polarizations. Cooling temperature is related to the internal temperature fluctuation and collision with residual air molecules as well as laser shot noise. Cooling and trapping of the microsphere are controlled by optical polarization of the optical waves. Orthogonal polarization cooling, compared with nonorthogonal polarization cooling, has higher cooling efficiency and is free from thermo-refractive and -elastic noises and thus has lower temperature. Simultaneous cooling and optical trapping of the microsphere could be achieved with the two nonorthogonally polarized optical fields. Our numerical simulation shows that a cooling temperature of less than 1 mK in a high vacuum environment could be achieved. Finally, influence of the electric affinity of a charged microsphere on optical forces has been investigated. The current scheme is for 1D cooling and trapping, but it could be extended to the 3D case.
Suppression of self-induced thermal lensing in stimulated Raman scattering of liquids
Authors: Hazan Zion , Ganot Yuval , Bar Ilana
Published: October 2020

Stimulated Raman scattering (SRS), due to the interaction of intense laser beams with Raman active media, provides an effective operational mode for frequency conversion, downgraded (primarily in liquids) by self-induced thermal lensing (TL). Here, a unique setup, including a pump laser beam [green (532 nm), 10 Hz, 5 ns] passing through a rotating cell, filled with a saturated aqueous solution of sodium nitrate (

N
a
N

O

3

) was tested, for conversion to a yellow (564 nm) beam. This distinct geometry allowed each pump pulse to pass through a “fresh” solution, practically eliminating TL. A sharp enhancement in SRS generation (

∼

20

%

) and observation of unexpanded beams’ cross sections at the cell exit verified TL removal. The results and the obtained physical insight from the

N
a
N

O

3

model system point to the promise of this approach for suppression of impeding TL in frequency conversion by SRS in liquids.
Design of efficient radiative emission and daytime cooling structures with Si3N4 and SiO2 nanoparticle laminate films
Authors: Wray Parker R. , Su Magel P. , Atwater Harry A.
Published: October 2020

Research on radiative cooling has attracted recent widespread interest owing to the potential for low-cost passive structures to enable large-scale thermal energy management. Using a generalized effective medium theory, we theoretically show that two-layer films comprised of SiO2 and Si3N4 nanoparticle layers on an Ag back reflector exhibit superior radiative cooling compared to single-layer or two-layer dense solid films, and can outperform other reported designs. The performance enhancement is a result of the ability to tune the nanoparticle fill fraction, which improves the spectral match between emissivity of this structure and the atmospheric transmission window. We also propose a standardized method for comparing the performance of radiative cooling structures reported by the research community.
Observation of 2D omnidirectional invisibility from an electrically large cluster under TE polarization
Authors: Hu Xiaojun , Li Ran , Peng Liang , Wang Rui , Huangfu Jiangtao , Ran Lixin , Ye Dexin
Published: October 2020

The concept of perfect invisibility in free space implies an object neither reflects nor refracts optical waves coming from arbitrary directions, regardless of its shape and size. An optimal solution to realize such a peculiar phenomenon is to tune the constitutive parameters of the object to be identical to air. In particular, to render zero extinction from an existing object by covering some additional structures, is of importance for practical implementations, which is challenging. Here, we demonstrate and propose that a thin metallic wire can be tuned to be air-like under TE polarization, with the aid of an external enclosure. This is achieved through a precise dispersion engineering with independently controllable electric and magnetic responses. Consequently, an electrically large cluster composed of multiple thin wires can be safely hidden in free space, without any macroscopic cloaking structure, which is verified by full-wave simulations and experiments. The measured results on an electrically large airplane-like sample show the excellent performance of 2D omnidirectional invisibility at the designed frequency. This proposed metamaterial would be helpful in enhancing the mechanical stability, electrical conduction, and heat dissipation of a device (or system) by extra wires (or pipes), without disturbing its electromagnetic characteristics.
Demonstration of focal length tuning by rotational varifocal moiré metalens in an ir-A wavelength
Authors: Iwami Kentaro , Ogawa Chikara , Nagase Tomoyasu , Ikezawa Satoshi
Published: October 2020

This paper reports an experimental demonstration of moiré metalens which shows wide focal length tunability from negative to positive by mutual angle rotation at the wavelength of 900 nm. The moiré metalens was developed using high index contrast transmitarray meta-atoms made of amorphous silicon octagonal pillars, which is designed to have polarization insensitivity and full 2π phase coverage. The fabricated moiré metalens showed focal length tunability at the ranges between ±1.73 – ±5 mm, which corresponds to the optical power ranges between ±578 – ±200 m−1 at the mutual rotation between ±90 degrees.
Dark-line laser
Authors: To Bao-Dong , Wu Ming-Hsiung , Huang Yen-Chieh
Published: October 2020

A laser is meant to emit coherent radiation at a particular wavelength. Here, we demonstrate a laser that is prohibited to emit at a particular wavelength, called a dark line in the emission background of its gain spectrum. Specifically, we installed a 150 µm thick etalon mirror on an ytterbium-doped fiber laser. The laser suffers from 100% loss at the resonance of the etalon and generates a dark line in its emission spectrum. The interplay among the etalon resonance, homogenous gain broadening, and gain competition allows wavelength tuning and multiple-color emission from the laser.
Mid-infrared quantum cascade laser frequency combs based on multi-section waveguides
Authors: Wang Ruijun , Täschler Philipp , Kapsalidis Filippos , Shahmohammadi Mehran , Beck Mattias , Faist Jérôme
Published: October 2020

We present quantum cascade laser (QCL) frequency comb devices with engineered waveguides for managing the dispersion. The QCL waveguide consists of multiple sections with different waveguide widths. The narrow and wide sections of the waveguide are designed in a way to compensate the group velocity dispersion (GVD) of each other and thereby produce a flat and slightly negative GVD for the QCL. The QCL exhibits continuous comb operation over a large part of the dynamic range of the laser. Strong and narrow-linewidth intermode beatnotes are achieved in a more than 300 mA wide operation current range. The comb device also features considerably high output power (

>

380

m
W

) and wide optical bandwidth (

>

55

c
m

−
1

).
Single-shot, shadowless total internal reflection fluorescence
microscopy via annular fiber bundle
Authors: Croop Benjamin , Tang Jialei , Han Kyu Young
Published: October 2020

We demonstrate a method of generating instantaneous and uniform total internal reflection fluorescence (TIRF) excitation by using an annular fiber bundle and spatially incoherent light sources. We show the flexibility of our method in that it can generate TIRF excitation with either a laser light source or an LED of different wavelengths, and facilitate switching between TIRF and epi illumination. In this report we detail the design of the fiber bundle, then demonstrate the performance via single-molecule imaging in the presence of high background and high throughput, and uniform TIRF imaging of cells over a large field of view. Our versatile method will enable quantitative shadowless TIRF imaging.
Iterative point set registration for aligning scRNA-seq data
Authors: Alavi Amir , Bar-Joseph Ziv
Published: October 2020

Several studies profile similar single cell RNA-Seq (scRNA-Seq) data using different technologies and platforms. A number of alignment methods have been developed to enable the integration and comparison of scRNA-Seq data from such studies. While each performs well on some of the datasets, to date no method was able to both perform the alignment using the original expression space and generalize to new data. To enable such analysis we developed Single Cell Iterative Point set Registration (SCIPR) which extends methods that were successfully applied to align image data to scRNA-Seq. We discuss the required changes needed, the resulting optimization function, and algorithms for learning a transformation function for aligning data. We tested SCIPR on several scRNA-Seq datasets. As we show it successfully aligns data from several different cell types, improving upon prior methods proposed for this task. In addition, we show the parameters learned by SCIPR can be used to align data not used in the training and to identify key cell type-specific genes.
Leishmania differentiation requires ubiquitin conjugation mediated by a UBC2-UEV1 E2 complex
Authors: Burge Rebecca J. , Damianou Andreas , Wilkinson Anthony J. , Rodenko Boris , Mottram Jeremy C.
Published: October 2020

Post-translational modifications such as ubiquitination are important for orchestrating the cellular transformations that occur as theLeishmaniaparasite differentiates between its main morphological forms, the promastigote and amastigote. 2 E1 ubiquitin-activating (E1), 13 E2 ubiquitin-conjugating (E2), 79 E3 ubiquitin ligase (E3) and 20 deubiquitinating cysteine peptidase (DUB) genes can be identified in theLeishmania mexicanagenome but, currently, little is known about the role of E1, E2 and E3 enzymes in this parasite. Bar-seq analysis of 23 E1, E2 and HECT/RBR E3 null mutants generated in promastigotes using CRISPR-Cas9 revealed numerous loss-of-fitness phenotypes in promastigote to amastigote differentiation and mammalian infection. The E2s UBC1/CDC34, UBC2 and UEV1 and the HECT E3 ligase HECT2 are required for the successful transformation from promastigote to amastigote and UBA1b, UBC9, UBC14, HECT7 and HECT11 are required for normal proliferation during mouse infection. Of all ubiquitination enzyme null mutants examined in the screen, Δubc2and Δuev1exhibited the most extreme loss-of-fitness during differentiation. Null mutants could not be generated for the E1 UBA1a or the E2s UBC3, UBC7, UBC12 and UBC13, suggesting these genes are essential in promastigotes. X-ray crystal structure analysis of UBC2 and UEV1, orthologues of human UBE2N and UBE2V1/UBE2V2 respectively, reveal a heterodimer with a highly conserved structure and interface. Furthermore, recombinantL.mexicanaUBA1a can load ubiquitin onto UBC2, allowing UBC2-UEV1 to form K63-linked di-ubiquitin chainsin vitro. Notably, UBC2 can cooperatein vitrowith human E3s RNF8 and BIRC2 to form non-K63-linked polyubiquitin chains, showing that UBC2 can facilitate ubiquitination independent of UEV1, but association of UBC2 with UEV1 inhibits this ability. Our study demonstrates the dual essentiality of UBC2 and UEV1 in the differentiation and intracellular survival ofL.mexicanaand shows that the interaction between these two proteins is crucial for regulation of their ubiquitination activity and function.
Voilà mon cœur, das vielas ao cais:
Authors: Santos Gleison Guilherme dos
Published: October 2020

Resumo

 

     Com esta pesquisa proponho uma reflexão sobre os resultados de uma exploração criativa cênica, a partir de um espetáculo de estética híbrida e experimental, vislumbrando utilizar a semiótica peirciana e o conceito de transcriação (tradução poética), de Haroldo de Campos, como procedimentos na criação em teatro. Uso como principal referência para o contexto dramatúrgico, a personagem Geni, da peça Ópera do Malandro, de Chico Buarque.

Palavras-chave: Geni e o zepelim, Leonilson, procedimentos de criação cênica, semiótica

 

 

 

Résumé

 

     Dans cette recherche, je propose une réflexion sur les résultats d'une exploration créative scénique, à partir d'un spectacle d'esthétique hybride et expérimentale,en envisageant  utiliser la sémiotique peircienne et le concept de transcréation (traduction poétique) de Haroldo de Campos, comme procédure de création en théâtre. J'utilise comme référence principale pour le contexte dramaturgique, le personnage Geni de la pièce de théâtre “Opéra do Malandro” de Chico Buarque.

Mots-clés: Geni et le zeppelin, Leonilson, procédures d’élevage scénique, sémiotique
Aprender a vivir. Existencia, pensamiento, huella en/de Derrida.
Authors: Fernández Agis Domingo
Published: October 2020

En este trabajo abordo el problema de la herencia nietzscheana en el pensamiento de Jacques Derrida como base para plantear la cuestión de la huella de éste último en la filosofía actual. Para ello, me aproximo a la relación entre vida e ideal de vida, tal como la pensaron ambos. Partiendo de este aspecto, planteo el problema de la relación entre vida y obra, la cuestión de la identidad personal, la valoración del pensamiento como actividad crítica y la cuestión de la posibilidad de lo imposible, que resulta central en el pensamiento derridiano. A través de todo ello, pretendo poner de manifiesto la enorme proyección de futuro que a mi juicio tiene la obra de Derrida.
Optimal value of past samples for decision making in cognitive radio networks
Authors: Hernandez Cesar , Jara Estupiñan Jefferson , Giral Ramirez Diego Armando
Published: October 2020

Contexto: El modelado y predicción del uso del espectro por parte de los PU es un aspecto importante para reducir la interferencia entre los SU y PU, y mejorar el desempeño de la decisión espectral. Lo anterior requiere de información espectral pasada, que permita al algoritmo modelar el comportamiento del PU.

Objetivo: Determinar el valor óptimo de muestras pasadas y tiempo de recalculo de criterios de decisión, para los algoritmos de toma de decisiones en redes de radio cognitiva.

Metodología: Se realizan varios experimentos de simulación a partir del algoritmo FFAHP, en dos diferentes enfoques, tiempo-real y mejor-esfuerzo, con tráfico alto y bajo, en la banda de frecuencia GSM. Se realiza un análisis estadístico de los datos obtenidos, variando los parámetros de time range, mientras criteria time permanece constante, y viceversa.

Resultados: Para tráfico alto es suficiente con tomar 1800 muestras anteriores para calcular el valor inicial de los parámetros y actualizarlos cada 10 minutos (1800). Si el tráfico es bajo es suficiente con tomar 5400 muestras anteriores para calcular el valor inicial de los parámetros y actualizarlos cada 10 minutos (1800).

Conclusiones: No es necesario un número elevado de muestras anteriores para determinar el valor inicial de los parámetros de decisión para obtener un buen desempeño de la tasa de handoff, así como tampoco lo es para la actualización de los mismos, para un tráfico correspondiente a la banda de frecuencia GSM.

Financiamiento: El presente trabajo es un resultado de un proyecto de investigación financiado por el Centro de Investigaciones y Desarrollo Científico de la Universidad Distrital Francisco José de Caldas.
Inconvenientes del uso de promedios de parámetros fisicoquímicos no conservativos, ejemplos de caso lagunas costeras mexicanas
Authors: De la Lanza Espino Guadalupe , Hernández Pulido Salvador , Gutiérrez Mendieta Francisco José
Published: October 2020

Contexto: La amplia variación en los parámetros fisicoquímicos y biológicos costeros, son resultado de factores locales naturales: clima, geomorfología, influencia marina, descargas fluviales, como los antropogénicos, resultando variaciones amplias y esto ha dado lugar al uso de promedios que no reflejan la realidad acuática. Por lo anterior el presente estudio analiza el comportamiento teórico de los parámetros conservativos y los no conservativos y biológicos de lagunas costeras tanto del Golfo de México como del Pacífico mexicano, a través de datos referidos como mínimos, máximos y promedio, y su grado certeza.

Metodología: Se recabó información fisicoquímica y biológica de 11 lagunas costeras con diferencias ambientales extremas: cinco de la vertiente del Golfo de México y seis del Pacífico mexicano, según la disponibilidad y continuidad de la información.

Resultados: Los intervalos de los parámetros conservativos y no conservativos (máximo y mínimo) fueron significativamente amplios, asociados a factores climáticos estacionales (precipitaciones y estiaje), descargas fluviales temporales o permanentes, manejo del agua en el área terrestre adyacente, así como por la influencia mareal. Por lo tanto, emplear un promedio basado en máximos y mínimos de esos factores no es recomendable. En los parámetros no conservativos hubo diferencias de variación cortas o de mayor amplitud; debidas a la dinámica de circulación, época, incluso, a la anualidad hasta la interanualidad, por lo que no es recomendable utilizar promedios. Con base en lo anterior, se estimaron mayores variaciones en los parámetros acuáticos en las lagunas del Pacífico y mayor homogeneidad en las del Golfo de México, resultado de la regularidad fluvioclimática, menor influencia antropogénica y de menor manejo costero.

Conclusiones: Para un diagnostico con una visión integrativa de los factores fisicoquímicos y biológicos costeros, es necesario basarse en el conocimiento de las condiciones normales locales que incluyen: la dinámica física, fluvial, geomorfológica e influencias terrestres adyacentes, para diferenciarse de los impactos antropogénicos, que modifican las características acuáticas; por lo que no es adecuado referir los resultados como mínimos, máximos y promedios que en muchos casos el intervalo entre el primero y el último puede ser amplio, inseguro y erróneo; además de no ser repetitivos o permanentes y variar heterogéneamente, como se pudo apreciar en las lagunas elegidas del Golfo de México y Pacífico Mexicano.
Estrés académico en estudiantes que cursan asignaturas de Física en ingeniería: dos casos diferenciados en Colombia y México
Authors: Suárez Oscar Jardey , Ramírez Díaz Mario Humberto
Published: October 2020

Este artículo reporta el estudio de las variables subyacentes al estrés académico en dos poblaciones diferenciadas de estudiantes citadinos que cursan asignaturas de Física en instituciones de educación superior (Colombia y México). El inventario utilizado es el de Polo, Hernández y Pozo (1996), el cual mide dos dimensiones: respuestas al estrés y actividades que producen estrés. Se ha considerado una dimensión adicional que considera aspectos propios de la clase de Física. La población de estudiantes universitarios que participaron en cada comunidad fue de 124 por país. El instrumento tiene una confiabilidad de 0,918 (Col) y 0,937 (Mxn); la medida de adecuación muestral de Kaiser-Meyer-Olkin fue de 0,838 (Col) y 0,878 (Mxn); la varianza interpretada 61,40 % (Col) y 64,46 % (Mxn). Los resultados muestran cuatro variables subyacentes a la población de estudiantes en Colombia (respuestas al estrés [RE], interacción [I], la evaluación [E] y actividad escolar extra [AEE]); en tanto que en México hay tres variables subyacentes al estrés (respuestas al estrés [RE], la evaluación [E] y entorno escolar [EE]). Las respuestas al estrés tienen diferencias entre las poblaciones. La evaluación, al igual que otros estudios, se muestra como una variable que subyace al estrés académico en ambas poblaciones; sin embargo, su comprensión muestra diferentes fuentes.
Challenges in assessing the nature of effective collaboration in blended university courses
Authors: Ellis Robert A , Bliuc Ana-Maria , Han Feifei
Published: October 2020

The ability to collaborate effectively face-to-face and online represents a critical skill for university graduates. However, there are still challenges regarding how to accurately assess this skill through traditional student learning measures. To better understand the nature of effective collaboration of university students in blended courses, the current study drew on the student approaches to learning framework and social network analysis techniques. We examined how student approaches to inquiry, approaches to online learning technologies, perceptions of the blended learning environment, different learning outcomes and configurations of collaboration are related. The methodologies commonly used in student approaches to learning research identified deep and surface approaches to inquiry and technologies, positive and negative perceptions of the integration of the learning environment, and of online workload, which also showed logical alignment with relatively better and poorer academic achievement in the course. Based on approaches, perceptions, and learning outcomes, students were divided into groups orientated towards understanding versus reproducing learning. The social network analysis techniques revealed features of different configurations of collaborations by different groups of students and their choices as to whether and with whom to collaborate during the learning process. Nuanced differences were found amongst different configurations of collaborations.

Implications for practice or policy:

When assessing student experience of collaboration, social network analysis techniques may be able to describe nuanced differences amongst different collaborative configurations.

To encourage students’ collaboration, assessment tasks involving a large proportion of mandatory collaborative activities should be considered.

To help student improve experience of collaboration, teachers may consider pairing students with a reproducing learning orientation with those having a deep disciplinary understanding.