bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Smartphone Overuse on Grip Strength, Pinch Strength, and Cross-Sectional Area of Flexor Pollicis Longus Tendon and Median Nerve
Authors: Samuel Paul Silvian , Alahmari Khalid A , Adam Mohamed , Reddy Ravi Shankar , Ahmad Irshad , Kakaraparthi Venkata Nagaraj , Rengaramanujam Kanagaraj , Tedla Jaya Shanker , Hussein Almohiy , Alshahrani Mastour Saeed
Published: July 2021

Background and Aim The adverse effects of smartphone size and weight on the hand and hand function have not been studied extensively. This study aimed to investigate the changes to the flexor pollicis longus tendon and median nerve using diagnostic ultrasound for high and low addiction smartphone users.

Methodology In this cross-sectional study, 54 healthy male university students were divided into two groups according to the Smartphone Addiction Scale: high and low users. Demographic data, hand grip strength (kg), pinch strength (kg), and smartphone weight, length and width were measured and recorded. Diagnostic ultrasound examination determined the cross-sectional area of the median nerve (mm2) and flexor pollicis longus tendon (mm2) of the dominant and non-dominant hand.

Result The cross-sectional area of the median nerve was significantly higher in the high-user group (7.4±1.3 mm2) than the low-user group (6.7±1.0 mm2). The correlation of phone weight, length and width with median nerve area was respectively positive, higher and significant (0.718, 0.747, and 0.733; p<0.05). The flexor pollicis longus tendon in the mid-thenar region was moderately positively correlated with phone length (0.430; p<0.02) for high addiction smartphone users.

Conclusion The findings of the current study demonstrates that change to the median nerve and flexor pollicis longus tendon, could be linked to the width, weight and length of the smartphone and high addiction.
Regioselective Iodine/Zinc Exchange for the Selective Functionalization of Polyiodinated Arenes and Heterocycles in Toluene
Authors: Sanchez Florian , Desaintjean Alexandre , Knochel Paul , Danton Fanny
Published: July 2021

Regioselective I/Zn-exchange reactions were performed on polyiodinated arenes or heterocycles within 20 minutes at 0–25 °C using the bimetallic combination pTol2Zn·2LiOR [R = (CH2)2N(Me)(CH2)2NMe2] in toluene. The resulting diaryl- or diheteroarylzincs reacted well with allylic bromides and acyl chlorides to provide functionalized (hetero)aryl iodides in good yields.
Oxidative Intramolecular C–C Bond Formation Reactions of 1,2-Diarylbenzenes: Syntheses of Highly Conjugated Double-Bridged Polycyclic Aromatic Hydrocarbons
Authors: Sugiura Ken-ichi , Islam Md. Rafikul , Nishinaga Tohru , Hirabayashi Kazunori , Shimizu Toshio
Published: July 2021

Oxidation reactions of 1,2-diarylbenzenes induce intramolecular C–C bond formation. The substrates studied were prepared by the stepwise Suzuki–Miyaura coupling reaction that introduced 2-naphthyl, 2-anthranyl, and 2-pyrenyl groups on the ortho-positions of benzene. The subsequent oxidation reaction with FeCl3 induced an oxidative C–C bond formation reaction in the interior regions of the molecules. In marked contrast to our previous observations, two C–C bonds were formed. Theoretical calculations indicated that large spin densities at the reaction positions of the bis(cation radical) and/or cation radical species are needed for the C–C bond formation. The π-expanded molecules obtained showed bathochromic shifts in the absorption spectra.
Transition-Metal-Catalyzed Enantioselective α-Arylation of Carbonyl Compounds to Give Tertiary Stereocenters
Authors: Orlandi Manuel , Escudero-Casao Margarita , Licini Giulia
Published: July 2021

Enantioenriched α-aryl carbonyl compounds are ubiquitous in natural products and biologically active compounds. Their synthesis has been explored over the last few decades and several methods now exist that allow for the enantioselective formation of a C(sp3)-C(sp2) bond in the α-position to a carbonyl group. However, although the formation of quaternary stereocenters has been fairly well established, the enantioselective formation of tertiary stereocenters proved more challenging due to facile product post-reaction racemization. In this short review, we summarize the methods reported to date for the asymmetric α-arylation of enolates and analogues that rely on transition-metal catalysis.

1 Introduction

2 Nucleophile Pre-activation

3 Activation via Aminocatalysis

4 Formation of Constrained Stereocenters

5 Concluding Remarks
Catalytic, Enantioselective Diamination of Alkenes
Authors: Denmark Scott E. , Tao Zhong-Lin
Published: July 2021

Enantioselective diamination of alkenes represents one of the most straightforward methods to access enantioenriched, vicinal diamines, which are not only frequently encountered in biologically active compounds, but also have broad applications in asymmetric synthesis. Although the analogous dihydroxylation of olefins is well-established, the development of enantioselective olefin diamination lags far behind. Nevertheless, several successful methods have been developed that operate by different reaction mechanisms, including a cycloaddition pathway, a two-electron redox pathway, and a radical pathway. This short review summarizes recent advances and identifies limitations, with the aim of inspiring further developments in this area.

1 Introduction

2 Cycloaddition Pathway

3 Two-Electron Redox Pathway

3.1 Pd(0)/Pd(II) Diamination

3.2 Pd(II)/Pd(IV) Diamination

3.3 I(I)/I(III) Diamination

3.4 Se(II)/Se(IV) Diamination

4 One-Electron Radical Pathway

4.1 Cu-Catalyzed Diamination

4.2 Fe-Catalyzed Diamination

5 Summary and Outlook
Cluster Preface: Perspectives on Organoheteroatom and Organometallic Chemistry
Authors: Jiang Xuefeng
Published: July 2021

Xuefeng Jiang is a professor at East China Normal University. He received his B.S. degree in 2003 from Northwest University (China). He then joined Professor Shengming Ma’s research group at the Shanghai Institute of Organic Chemistry (SIOC), Chinese Academy of Sciences, where he received his Ph.D. degree in 2008. From 2008 to 2011, Xuefeng worked as a postdoctoral researcher on the total synthesis of natural products in the research group of Professor K. C. Nicolaou at The Scripps Research Institute (TSRI). His independent research interests have focused on green organosulfur chemistry and methodology-­oriented total synthesis.
SARS-CoV-2 Infection and Placental Pathology
Authors: Leal Caio Ribeiro Vieira , Maciel Rayra Amana Macêdo , Corrêa Júnior Mário Dias
Published: July 2021

Placental pathophysiology in SARS-CoV-2 infection can help researchers understand more about the infection and its impact on the maternal/neonatal outcomes. This brief review provides an overview about some aspects of the placental pathology in SARS-CoV-2 infection. In total, 11 papers were included. The current literature suggests that there are no specific histopathological characteristics in the placenta related to SARS-CoV-2 infection, but placentas from infected women are more likely to show findings of maternal and/or fetal malperfusion. The most common findings in placentas from infected women were fibrin deposition and intense recruitment of inflammatory infiltrates. The transplacental transmission of this virus is unlikely to occur, probably due to low expression of the receptor for SARS-CoV-2 in placental cell types. Further studies are needed to improve our knowledge about the interaction between the virus and the mother-fetus dyad and the impact on maternal and neonatal/fetal outcomes.
Predictive Outcome Modeling of Preoperative Clinical Symptoms and Electrodiagnostic Data in Tarsal Tunnel Surgery
Authors: Seidel Geoffrey K. , Jamal Salma Al , Weidert Eric , Carington Frederick , Andary Michael T. , Millis Scott R. , Loder Brian G.
Published: July 2021

Background The relationship between tarsal tunnel syndrome (TTS), electrodiagnostic (Edx) findings, and surgical outcome is unknown. Analysis of TTS surgical release outcome patient satisfaction and comparison to Edx nerve conduction studies (NCSs) is important to improve outcome prediction when deciding who would benefit from TTS release.

Methods Retrospective study of 90 patients over 7 years that had tarsal tunnel (TT) release surgery with outcome rating and preoperative tibial NCS. Overall, 64 patients met study inclusion criteria with enough NCS data to be classified into one of the following three groups: (1) probable TTS, (2) peripheral polyneuropathy, or (3) normal. Most patients had preoperative clinical provocative testing including diagnostic tibial nerve injection, tibial Phalen's sign, and/or Tinel's sign and complaints of plantar tibial neuropathic symptoms. Outcome measure was percentage of patient improvement report at surgical follow-up visit.

Results Patient-reported improvement was 92% in the probable TTS group (n = 41) and 77% of the non-TTS group (n = 23). Multivariate modeling revealed that three out of eight variables predicted improvement from surgical release, NCS consistent with TTS (p = 0.04), neuropathic symptoms (p = 0.045), and absent Phalen's test (p = 0.001). The R
2 was 0.21 which is a robust result for this outcome measurement process.

Conclusion The best predictors of improvement in patients with TTS release were found in patients that had preoperative Edx evidence of tibial neuropathy in the TT and tibial nerve plantar symptoms. Determining what factors predict surgical outcome will require prospective evaluation and evaluation of patients with other nonsurgical modalities.
Dry Arthroscopy Distal Radioulnar Joint and Foveal Insertion: Surgical Technique
Authors: Ecker Jeff , Andrijich Courtney
Published: July 2021

Background Arthroscopy of the distal radioulnar joint is considered to be difficult to perform. At this time the integrity of the foveal insertion is indirectly evaluated with a hook test. If a hook test is positive it is inferred that the foveal insertion is torn or incompetent.

Description of Technique The ideal way to evaluate the foveal insertion is by direct visualization and probing. In order to do this, arthroscopic examination of the distal radioulnar joint and foveal insertion is required. The article describes how to reliably perform “dry” arthroscopy of the distal radioulnar joint and foveal insertion using a 1.9 mm arthroscope to accurately assess the triangular fibrocartilage complex and foveal insertion.

Patient and Methods A total of 169 dry DRUJ arthroscopies were performed by the primary author between January 2018 and February 2021.

Results Using this technique, the foveal insertion was successfully visualized in 168 cases (99%).

Conclusion Dry arthroscopy of the DRUJ is a reliable technique to evaluate the integrity of the foveal insertion.
Oxidant and Antioxidant Balance in Children with Community-Acquired Pneumonia
Authors: Aykac Kubra , Ozsurekci Yasemin , Tanir Basaranoglu Sevgen , Avcioglu Gamze , Karadag Oncel Eda , Erel Ozcan , Cengiz Ali Bulent , Karahan Sevilay , Ceyhan Mehmet
Published: July 2021

Objective The balance between oxidant and antioxidant defense mechanisms is crucial. In this article, we aimed to evaluate the role of this balance in community-acquired pneumonia (CAP) in children.

Methods We analyzed serum oxidant and antioxidant stress parameters according to the clinical and demographic data of children with CAP and compared them with healthy controls. Serum total antioxidant status (TAS) and total oxidant status (TOS) were evaluated and compared between the groups, along with levels of ischemia-modified albumin (IMA), antioxidant enzymes, nonenzymatic antioxidant factors, and plasma thiol.

Results Of 160 children evaluated, 106 had CAP (54 outpatients and 52 inpatients), and the other 54 were healthy (control group). Total thiol and native thiol levels were significantly lower in the inpatient group compared with the outpatient group (p = 0.004 and p = 0.005, respectively). Serum IMA differed significantly among the groups (p = 0.001), with inpatients showing the highest level. A positive correlation was found between serum IMA and C-reactive protein levels in patients with pneumonia (r = 0.351; p = 0.001).

Conclusion Parameters that provide information about antioxidant capacity may be useful in the diagnosis and prognosis of pneumonia. Our results suggest that plasma thiol levels and IMA may be good candidate biomarkers to predict hospitalization for CAP in children.
Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff
Authors: Cakir Salih Cagri , Dorum Bayram Ali , Koksal Nilgun , Ozkan Hilal , Yazici Zeynep , Parlak Mufit , Gulleroglu Nadide Basak
Published: July 2021

Objective Portable X-rays remain one of the most frequently used diagnostic procedures in neonatal intensive care units (NICU). Premature infants are more sensitive to radiation-induced harmful effects. Dangers from diagnostic radiation can occur with stochastic effects. We aimed to determine the radiation exposure in premature infants and staff and determine the scattering during X-ray examinations in the NICU.

Study Design In this prospective study, dosimeters were placed on premature infants who were ≤1,250 g at birth and ≤30 weeks of gestational age who stayed in the NICU for at least 4 weeks. The doses were measured at each X-ray examination during their stay. The measurements of the nurses and the doctors in the NICU were also performed with dosimeters over the 1-month period. Other dosimeters were placed in certain areas outside the incubator and the results were obtained after 1 month.

Results The mean radiation exposure of the 10 premature infants, monitored with dosimeters, was 3.65 ± 2.44 mGy. The mean skin dose of the six staff was 0.087 ± 0.0998 mSV. The mean scattered dose was 67.9 ± 26.5 µGy.

Conclusion Relatively high exposures were observed in 90% of the patients and two staff. The radiation exposure levels of premature infants and staff may need to be monitored continuously.

Key Points
Indian College of Radiology and Imaging Evidence-Based Guidelines for Percutaneous Image-Guided Biliary Procedures
Authors: Madhusudhan Kumble Seetharama , Jineesh Valakkada , Keshava Shyamkumar Nidugala
Published: July 2021

Percutaneous biliary interventions are among the commonly performed nonvascular radiological interventions. Most common of these interventions is the percutaneous transhepatic biliary drainage for malignant biliary obstruction. Other biliary procedures performed include percutaneous cholecystostomy, biliary stenting, drainage for bile leaks, and various procedures like balloon dilatation, stenting, and large-bore catheter drainage for bilioenteric or post-transplant anastomotic strictures. Although these procedures are being performed for ages, no standard guidelines have been formulated. This article attempts at preparing guidelines for performing various percutaneous image-guided biliary procedures along with discussion on the published evidence in this field.
In Achilles Tendon Disorders, Will Sonoelastography Add to Grey-Scale Ultrasound? Using MRI as Gold Standard
Authors: Kandil Nour Mohamed , Abdelkarim Maha Ahmed , Abdelwahab Nagui Mohamed , Hashem Aya Mohamed
Published: July 2021

Background The aim of this study was to verify the findings of color-coded sonoelastography in Achilles tendon disorders against ultrasonographic and MR imaging findings, describing the elastographic patterns and correlating their diagnostic ability to magnetic resonance imaging (MRI) as a gold standard.

Results Our study showed that sonoelastography appeared to be highly sensitive to ultrasonographically detected changes, with 100% sensitivity, 16.6% specificity, 73% positive predictive value, and 100% negative predictive value, making it a good negative test to exclude suspected tendinopathy in equivocal cases. MRI examination was used as a gold standard. Elastographic grades showed moderate agreement to those of MRI (κ = 0.44, p < 0.001), while elastography had overall sensitivity of 87.5%, 100% specificity, and 90% accuracy in differentiating normal and pathological tendons.

Conclusion We concluded that sonoelastography is a sensitive method in the diagnosis of Achilles tendon pathologies detected by ultrasound examination and it can be well correlated to MRI with high specificity for pathological tendons.
Role of Imaging in a Case of Toxoplasmosis Presenting as Generalized Lymphadenopathy
Authors: Pratap Thara , Jalal Muhammed Jasim Abdul , K. Vishnu A. , Raja Senthil
Published: July 2021

Toxoplasmosis is caused by Toxoplasma gondii an obligate protozoan intracellular parasite. The disease has variable prevalence globally and is usually asymptomatic. Pregnant and immunocompromised people are at risk of getting infected. Enlarged lymph nodes are the most frequently observed clinical form of Toxoplasma in humans, mostly affecting posterior cervical nodes. Other organs usually affected are the brain and eyes. We present a case of toxoplasmosis with generalized lymphadenopathy mimicking metastasis in a lady with a previous history of operated pancreatic neoplasm.
Indian College of Radiology and Imaging (ICRI) Consensus Guidelines for the Early Management of Patients with Acute Ischemic Stroke: Imaging and Intervention
Authors: Londhe Shrikant R , GG Sharath Kumar , Keshava Shyamkumar N. , Mohan Chander
Published: July 2021

The medical science has witnessed significant change in the management of acute stroke patients as a result of recent advances in the field of stroke imaging and endovascular mechanical thrombectomy in addition to intravenous thrombolysis and optimization of stroke services in balance with available resources. Despite initial negative trials, we witnessed the publication of five multicenter randomized clinical trials showing superiority of the endovascular approach over standard medical management in patients with large vessel occlusion. The aim of this study is to provide comprehensive set of evidence-based recommendations regarding imaging and endovascular interventions in acute ischemic stroke patients.
TIPIC—A Newly Recognized Syndrome: Multimodality Imaging of a Rare Clinicoradiological Entity
Authors: Modi Tanvi , Verma Mitusha , Ahuja Gauri , Kamat Neemish , Patkar Deepak P.
Published: July 2021

Carotidynia is a controversial clinicopathological entity vastly described in Western literature as neck pain in the region of carotid bifurcation secondary to an underlying inflammatory etiology. Radiologically, this appears as perivascular inflammation and has recently been designated as transient perivascular inflammation of the carotid artery (TIPIC) syndrome. The authors of this report discuss the multimodality imaging features of a rare case of this disease in our country to familiarize radiologists with the imaging findings and to encourage the inclusion of TIPIC syndrome as a differential diagnosis for focal neck pain.
Diagnostic Utility of Mean Peak Systolic Velocity of Superior Thyroid Artery in Differentiating Graves’ Disease from Thyroiditis
Authors: Sarangi Pradosh K. , Parida Sasmita , Mangaraj Swayamsidha , Mohanty Binoy K. , Mohanty Jayashree , Swain Basanta M.
Published: July 2021

Background Differentiating Graves’ disease from thyroiditis can be at times clinically challenging. The gold standard test (thyroid nuclear imaging scan) is expensive, not routinely available, and has radiation exposure. Color Doppler ultrasonography of thyroid represents a suitable alternate which can be used for differentiating these conditions by studying thyroid blood flow parameters.

Aim We aimed to investigate the use of thyroid blood flow parameters’ assessment of the superior thyroid artery (STA) and common carotid artery (CCA) with color Doppler ultrasonography for differentiating Graves’ disease from thyroiditis.

Materials and Methods This is a cross-sectional study on 111 patients with newly diagnosed thyrotoxicosis (82 with Graves’ disease and 29 with thyroiditis) and 45 years of age and sex-matched healthy controls. All patients underwent detailed clinical and necessary investigations. Color Doppler ultrasonography of the thyroid gland and spectral flow analysis of both superior thyroid arteries was done using standard protocol. Sensitivity and specificity for mean peak systolic velocity of STA (STA-PSV) cut-offs were calculated using receiver operating characteristic curves.

Results Patients with Graves’ disease have significantly higher free tri-iodothyronine (FT3) levels, free thyroxine (FT4) levels, antithyroid stimulating hormone receptor antibody (TRAb) levels, and thyroid volume as compared with those with thyroiditis. The mean STA-PSV of patients with Graves’ disease was significantly higher than thyroiditis and control group. Mean STA-PSV greater than 54.3 cm/s had 82.9% sensitivity and 86.2% specificity in diagnosing Graves’ disease. Mean PSV-STA/PSV-CCA ratio of 0.40 was 80.5% sensitive and 86.2% specific for Graves’ disease.

Conclusion Mean STA-PSV has high sensitivity and specificity in differentiating Graves’ disease from thyroiditis and can be used routinely in clinical practice as a cheap and invaluable diagnostic tool.
Loes Score: Clinical and Radiological Profile of 22 Patients of X-Linked Adrenoleukodystrophy: Case Series from a Single Center
Authors: Kumar Somesh , Sait Haseena , Polipalli Sunil K. , Pradhan Gaurav S. , Pruthi Sumit , Kapoor Seema
Published: July 2021

Introduction X-linked adrenoleukodystrophy (X-ALD) is a devastating disease with a wide spectrum of presentation ranging from asymptomatic to a rapidly progressive childhood cerebral form. The gene responsible for adrenoleukodystrophy is ABCD1 gene, required for β oxidation of fatty acids in various tissues. While biochemical and molecular techniques are available to confirm the diagnosis, brain magnetic resonance imaging (MRI) utilizing Loes score has been used for both prognosis and timely direction of hematopoietic stem cell therapy.

Materials and Methods During the study period of 2016 to 2020, 22 individuals including 19 individuals with features suggestive of X-ALD and 3 asymptomatic siblings were evaluated from a single center in North India. After biochemical and molecular confirmation of the disease, detailed clinical and radiological findings using MRI brain were documented. A radiological scoring pattern proposed by Loes was employed to identify the severity of the disorder.

Results The most common clinical presentations were visual difficulty and muscular weakness (58%). All symptomatic individuals had classic neuroimaging findings in the form of hyperintensities involving the parieto-occipital area and splenium of corpus callosum. Severe involvement in the form of global atrophy was observed in 52.6% of individuals. Asymptomatic siblings also showed neurological involvement based on MRI with highest Loes score of 9 in one individual.

Conclusion This case series describes the clinical and radiological profile and employment of Loes score in individuals with X-ALD. Early identification of asymptomatic individuals by neuroimaging and use of Loes severity score for monitoring and disease progression will help in making therapeutic decisions in a timely manner.
Modern methods of detecting single photons and their application in quantum communications
Authors: Koziy A.A. , Losev A.V. , Zavodilenko V.V. , Kurochkin Yu.V. , Gorbatsevich A.A.
Published: July 2021

We consider main methods for detecting single photons used in quantum communications, including the quantum key distribution (QKD) technology. Two most promising single photon detectors (SPDs) based on superconducting nanowires and on a single-photon avalanche diode are described. The most effective SPD designs are presented and their advantages and disadvantages are analysed from the point of view of the possibility of their use in QKD devices. The results of the work of various scientific groups conducting research on QKD are discussed, which makes it possible to trace the trends in the global technological development of this industry over the past five years.
Passive method of laser radiation smoothing using spectral dispersion
Authors: Sizmin D.V. , Pugacheva V.N. , Starodubtsev K.V. , Dushina L.A. , Gorchakov O.I. , Derkach V.N. , Voronich I.N.
Published: July 2021

A new version of the method for spatiotemporal smoothing of laser radiation using spectral dispersion is proposed, which does not require the use of high-frequency phase modulators, i.e. a method based on the use of a broadband master oscillator. An experimental study of this method has been conducted on the Luch laser facility.
Principle of measuring the electron population of a quantum dot using a single-photon transistor based on an array of quantum dots
Authors: Tsukanov A.V.
Published: July 2021

The scheme of a single-photon transistor formed by an array of semiconductor single-electron quantum dots in an optical resonator is considered. The spectral response of such a transistor depends on the Coulomb interaction of the electrons of the array with the electron at the measured quantum dot. An approximate analytical expression is obtained for the response function of a transistor with an arbitrary number of quantum dots. Using a one-dimensional array (chain) as an example, the dependences of the transistor response on the chain period, on the distance to the measured quantum dot, and on the degree of compensation for Coulomb effects are analysed. It is shown that the electron – photon dynamics of the transistor is substantially affected by the Förster effect, the suppression of which by alternating quantum dots with different symmetry of the excited state significantly increases the measurement accuracy.
Measurements of the absolute intensities of spectral lines of Kr, Ar, and O ions in the wavelength range of 10 – 18 nm under pulsed laser excitation
Authors: Vodop’yanov A.V. , Garakhin S.A. , Zabrodin I.G. , Zuev S.Yu. , Lopatin A.Ya. , Nechay A.N. , Pestov A.E. , Perekalov A.A. , Pleshkov R.S. , Polkovnikov V.N. , Salashchenko N.N. , Smertin R.M. , Ulasevich B.A. , Chkhalo N.I.
Published: July 2021

We have measured the absolute intensities of the spectral lines of Kr, Ar, and O ions (CO2gas), which are of interest for reflectometry, microscopy, and lithography in the wavelength range of 10 – 18 nm. We have used pulsed excitation by an Nd : YAG laser with an output wavelengthλ= 1064 nm, a pulse energy of 0.8 J, a pulse duration of 5.2 ns and a pulse repetition rate of 10 Hz. The targets are formed during gas outflow through a pulsed supersonic conical nozzle for an inlet gas pressure of 3.5 bar. A spectrometer based on X-ray multilayer mirrors and its calibration procedure are described in detail. The absolute intensities of the spectral lines of Kr IX (λ= 11.5 nm; number of photons:N= 9.3 × 1012photons pulse−1), Ar VIII (λ= 13.84 nm,N= 3 × 1012photons pulse−1), and O VI (λ= 12.98 nm,N= 5.17 × 1012photons pulse−1). The results are compared with the data obtained for Xe ions under the same experimental conditions at the same wavelengths.
Concept of a miniature photonic spatial switch based on an off-axis zone plate
Authors: Geints Yu.E. , Minin O.V. , Minin I.V.
Published: July 2021

A new concept of an all-optical wavelength-selective two-channel switch based on the photonic hook effect without the use of micromechanical devices or nonlinear materials is proposed. A prototype of such a device based on an off-axis Fresnel zone plate is considered and its main parameters are discussed. Due to the unique property of the photonic hook to change its curvature with respect to the irradiation wavelength λ, this switch is a promising candidate for the implementation of optical switching in modern optoelectronics and miniature ‘on-a-chip’ devices. Numerical simulation shows that the optical isolation of switched channels for a switch with linear dimensions of about (6λ)3 based on an off-axis zone plate can reach 18 – 20 dB during operation in the wavelength range of 1.5 – 1.9 μm.
Single-particle diffusional fingerprinting: A machine-learning framework for quantitative analysis of heterogeneous diffusion
Authors: Pinholt Henrik D. , Bohr Søren S.-R. , Iversen Josephine F. , Boomsma Wouter , Hatzakis Nikos S.
Published: July 2021

Significance

Single-particle tracking (SPT) analysis of individual biomolecules is an indispensable tool for extracting quantitative information from dynamic biological processes, but often requires some a priori knowledge of the system. Here we present “single-particle diffusional fingerprinting,” a more general approach for extraction of diffusional patterns in SPT independently of the biological system. This method extracts a set of descriptive features for each SPT trajectory, which are ranked upon classification to yield mechanistic insights for the species under comparison. We demonstrate its capacity to yield a dictionary of diffusional traits across multiple systems (e.g., lipases hydrolyzing fat, transcription factors diffusing in cells, and nanoparticles in mucus), supporting its use on multiple biological phenomena (e.g., drug delivery, receptor dynamics, and virology).
Independent Markov decomposition: Toward modeling kinetics of biomolecular complexes
Authors: Hempel Tim , del Razo Mauricio J. , Lee Christopher T. , Taylor Bryn C. , Amaro Rommie E. , Noé Frank
Published: July 2021

Significance

Molecular simulations of proteins are often interpreted using Markov state models (MSMs), in which each protein configuration is assigned to a global state. As we explore larger and more complex biological systems, the size of this global state space will face a combinatorial explosion, rendering it impossible to gather sufficient sampling data. In this work, we introduce an approach to decompose a system of interest into separable subsystems. We show that MSMs built for each subsystem can be later coupled to reproduce the behaviors of the global system. To aid in the choice of decomposition we also describe a score to quantify its goodness. This decomposition strategy has the promise to enable robust modeling of complex biomolecular systems.
Architecture of cell–cell junctions in situ reveals a mechanism for bacterial biofilm inhibition
Authors: Melia Charlotte E. , Bolla Jani R. , Katharios-Lanwermeyer Stefan , Mihaylov Daniel B. , Hoffmann Patrick C. , Huo Jiandong , Wozny Michael R. , Elfari Louis M. , Böhning Jan , Morgan Ashleigh N. , Hitchman Charlie J. , Owens Raymond J. , Robinson Carol V. , O’Toole George A. , Bharat Tanmay A. M.
Published: July 2021

Significance

Pseudomonas aeruginosa
bacteria form antibiotic-tolerant biofilms that pose significant challenges in clinical settings. Overcoming these challenges requires fundamental insights into how biofilms are formed, combined with innovative strategies to disrupt biofilms. Electron cryotomography in situ data presented here reveal the arrangement of the key
P. aeruginosa
adhesin CdrA at biofilm cell–cell junctions. Guided by our imaging data, we raised and characterized a CdrA-specific nanobody binder capable of disrupting these cell–cell junctions, thereby increasing the efficacy of antibiotic-mediated bacterial killing in biofilms. Together these data provide a pathway for developing effective alternative bacterial infection treatment strategies.
Articulatory and acoustic correlates of pharyngealization and
pharyngealization spread in Cairene Arabic
Authors: Hermes Zainab , Barlaz Marissa , Shosted Ryan , Liang Zhi-Pei , Sutton Brad P.
Published: July 2021

Pharyngealized speech sounds in Arabic are
articulated with a secondary posterior constriction and a lowered
tongue body. This articulatory configuration spreads to adjacent and
neighboring segments and has the acoustic consequence of lowering F2
in affected vowels. This study demonstrates that real-time Magnetic
Resonance Imaging (rtMRI) can be successfully used to examine the
role of (1) vowel length and (2) direction of spread in the extent
of the articulatory modifications that occur in the segments to
which pharyngealization spreads. Parallel acoustic measurements are
also acquired to examine and compare the extent of modifications in
formant frequencies. Results from both articulatory and acoustic
data demonstrate that the extent of pharyngealization spread
significantly varies with respect to these two factors.
LATFA
Authors: Marquis Alexandra
Published: July 2021

Research demonstrates the existing links between
oral language and literacy. The present chapter introduces the
Language Acquisition Test for Arabic (LATFA), an assessment tool
based on oral language skills to predict future literacy
difficulties in Emirati Arabic (EA) speaking children. A total of
forty-three EA speaking children were evaluated in EA using the
LATFA tool on their language perception (i.e., phonological
awareness & speech perception) and language production (i.e.,
morphological awareness & phonological production) at the end of
their first grade in school. A year later, the same children were
assessed with three literacy tasks. Results show that the LATFA tool
can help in predicting and identifying literacy difficulties faced
by EA speaking children.
Sentence repetition in children with autism spectrum disorder in
Saudi Arabia
Authors: Al-Hassan Mada Abdullah , Marinis Theodoros
Published: July 2021

This study investigated the morphosyntactic
abilities of Saudi Arabic-speaking children with Autism Spectrum
Disorder (ASD) using a Saudi Arabic Sentence Repetition Task
(Saudi-SRT) developed for this study. The first objective of the
study was to determine whether Saudi Arabic-speaking children with
autism living in Saudi have difficulties in morphosyntax as a
function of their verbal abilities. For this reason, the
participating children with autism were divided into subgroups of
children with autism with normal language (ALN) and children with
autism with language impairment (ALI) based on their verbal
abilities. The second objective of this study was to identify
whether the children’s performance differs as a function of the
scoring scheme used. Towards that aim, two scoring schemes were used
based on whether children repeated sentences verbatim versus whether
they used the targeted structure accurately. The third objective was
to address differences between the structures used in the Saudi-SRT.
The study involved 62 five- to seven-year-old children who speak
Saudi Arabic as their first language: 20 children with autism
(n = 10 ALN and n = 10 ALI)
and 42 typically developing (TD) control children. The children with
autism showed difficulties in morphosyntax as a function of their
verbal abilities, but the scoring scheme modulated this. In
nonverbal abilities and receptive vocabulary, ALI scored lower than
TD and ALN, and there was no difference between TD and ALN. As for
the grammatical abilities, the less sensitive verbatim scheme showed
a similar pattern in the ALN and ALI children who performed less
well than the TD children; in contrast, the more sensitive
structural scheme showed that in the most syntactically complex
structures, the ALN children performed similarly to the TD children
and better than the ALI children.
Student understanding of the first law and second law of thermodynamics
Authors: Brown Benjamin , Singh Chandralekha
Published: July 2021

We discuss common student difficulties with the first and second laws of thermodynamics found using a validated conceptual multiple-choice survey called the survey of thermodynamic processes and first and second laws suitable for introductory physics courses. The analysis of data from more than a thousand students using the validated survey at six different colleges in the US shows that not only introductory but also advanced physics students have many common difficulties with these concepts after traditional lecture-based instruction in relevant concepts. The findings of the common student difficulties with the first and second laws of thermodynamics discussed here can be useful for developing effective curricula and pedagogies in order to reduce student difficulties.
Long time finite dimensionality in charged fluids
Authors: Abdo Elie , Ignatova Mihaela
Published: July 2021

We consider long time dynamics of solutions of 2D periodic Nernst–Planck–Navier–Stokes systems forced by body charges and body forces. We show that, in the absence of body charges, but in the presence of fluid body forces, the charge density of the ions converges exponentially in time to zero, and the ion concentrations converge exponentially in time to equal time independent constants. This happens while the fluid continues to be dynamically active for all time. In the general case of body charges and body forces, the solutions converge in time to an invariant finite dimensional compact set in phase space.
The use of infrared thermography for the dynamic measurement of skin temperature of moving athletes during competition; methodological issues
Authors: Aylwin Polly E , Racinais Sebastien , Bermon Stéphane , Lloyd Alex , Hodder Simon , Havenith George
Published: July 2021

Objective. To investigate the use of infrared thermography (IRT) for skin temperature measurement of moving athletes during competition and its sensitivity to factors that are traditionally standardised. Approach. Thermograms were collected for 18 female athletes during the 20 km racewalk at the 2019 World Athletics Championships, with a medium-wave, cooled indium antimonide medium wave infrared band (MWIR) and a long-wave, uncooled microbolometer longwave infrared band (LWIR) infrared camera. Main results. The MWIR provided greater clarity images of motion due to a shorter exposure and response time and produced a higher percentage of acceptable images. Analysing acceptable images only, the LWIR and WMIR produced good levels of agreement, with a bias of −0.1 ± 0.6 °C in mean skin temperature for the LWIR. As the surface area of an ROI was reduced, the measured temperature became less representative of the whole ROI. Compared to measuring the whole area ROI, a single central pixel produced a bias of 0.3 ± 0.3 °C (MWIR) and 0.1 ± 0.4 °C (LWIR) whilst using the maximum and minimum temperature pixels resulted in deviations of 1.3 ± 0.4 °C and −1.1 ± 0.3 °C (MWIR) and 1.2 ± 0.3 °C and −1.3 ± 0.4 °C (LWIR). The sensitivity to air and reflected temperatures was lower for the LWIR camera, due to the higher emissivity of skin in its wavelength. Significance. IRT provides an appropriate tool for the measurement of skin temperature during real-world competition and critically during athlete motion. The cheaper LWIR camera provides a feasible alternative to the MWIR in low rate of motion scenarios, with comparable precision and sensitivity to analysis. However, the LWIR is limited when higher speeds prevent the accurate measurement and ability to capture motion.
Intermediate filaments ensure resiliency of single carcinoma cells, while active contractility of the actin cortex determines their invasive potential
Authors: Ficorella Carlotta , Eichholz Hannah Marie , Sala Federico , Vázquez Rebeca Martínez , Osellame Roberto , Käs Josef A
Published: July 2021

During the epithelial-to-mesenchymal transition, the intracellular cytoskeleton undergoes severe reorganization which allows epithelial cells to transition into a motile mesenchymal phenotype. Among the different cytoskeletal elements, the intermediate filaments keratin (in epithelial cells) and vimentin (in mesenchymal cells) have been demonstrated to be useful and reliable histological markers. In this study, we assess the potential invasiveness of six human breast carcinoma cell lines and two mouse fibroblasts cells lines through single cell migration assays in confinement. We find that the keratin and vimentin networks behave mechanically the same when cells crawl through narrow channels and that vimentin protein expression does not strongly correlate to single cells invasiveness. Instead, we find that what determines successful migration through confining spaces is the ability of cells to mechanically switch from a substrate-dependent stress fibers based contractility to a substrate-independent cortical contractility, which is not linked to their tumor phenotype.
Black phosphorus junctions and their electrical and optoelectronic applications
Authors: Deng Ningqin , Tian He , Zhang Jian , Jian Jinming , Wu Fan , Shen Yang , Yang Yi , Ren Tian-Ling
Published: July 2021

Black phosphorus (BP), an emerging two-dimensional material, is considered a promising candidate for next-generation electronic and optoelectronic devices due to in-plane anisotropy, high mobility, and direct bandgap. However, BP devices face challenges due to their limited stability, photo-response speed, and detection range. To enhance BP with powerful electrical and optical performance, the BP heterostructures can be created. In this review, the state-of-the-art heterostructures and their electrical and optoelectronic applications based on black phosphorus are discussed. Five parts introduce the performance of BP-based devices, including black phosphorus sandwich structure by hBN with better stability and higher mobility, black phosphorus homojunction by dual-gate structure for optical applications, black phosphorus heterojunction with other 2D materials for faster photo-detection, black phosphorus heterojunction integration with 3D bulk material, and BP via As-doping tunable bandgap enabling photo-detection up to 8.2 μm. Finally, we discuss the challenges and prospects for BP electrical and optical devices and applications.
Extensive study of optical contrast between bulk and nanoscale transition metal dichalcogenide semiconductors
Authors: Parmar Ankush , Kaur Jashangeet , Sharma Manish Dev , Goyal Navdeep
Published: July 2021

A remarkable refinement in the optical behavior of two-dimensional transition metal dichalcogenides (TMDs) has been brought to light when cleaved from their respective bulks. These atomically thin direct bandgap semiconductors are highly responsive to optical energy which proposes the route for futuristic photonic devices. In this manuscript, we have substantially focused on the optical study of MoS2 and WS2 nanosheets and comparative analysis with their bulk counterparts. The synthesis of nanosheets has been accomplished with liquid exfoliation followed by fabrication of thin films with drop-casting technique. X-ray diffraction and field emission scanning electron microscopy affirmed the morphology, whereas, UV–visible spectroscopy served as the primary tool for optical analysis. It was observed that several parameters, like optical conductivity, optical band-gap energy etc. have enhanced statistics in the case of exfoliated nanosheets as compared to their respective bulks. Some researchers have touched upon this analysis for MoS2, but it is completely novel for WS2. We expect our work to clearly distinguish between the optical behaviors of nanoscale and bulk TMDs so as to intensify and strengthen the research related to 2D-layered materials for optoelectronic and photovoltaic applications.
Design and Realization of Electrostatic Dynamic Potential Test Device
Authors: Lin Yiyong , Zhao Mei , Chen Jianbiao , Hu Shibin , Guo Junchao
Published: July 2021

Electrostatic potential testing is an important parameter for characterization of the electrostatic source. An electrostatic dynamic potential test device based on the principle of “signal virtual shielding-distributed parameter coverage” is proposed for the large sensor volume, complex signal processing and network transmission in current electrostatic dynamic potential tester. The problems of linear distortion and frequency response are solved. The basic principle of electrostatic dynamic potential test is introduced. The design requirements are defined.The hardware and software design and implementation process of electrostatic dynamic potential test device are described in detail. Finally the test verification and application of the device are given.
Research on Knowledge Graph Construction for Intelligent Operation and Maintenance of Electrical Transformers
Authors: Zhang Bowen , Gao Fei , Yang Ning , Hu Chengbo , Liu Ziquan
Published: July 2021

In the process of transformer equipment operation and maintenance, power companies encounter some problems, including of unstructured text data difficult to use, full caliber data difficult to deeply integrate and shallow equipment knowledge application. Based on artificial intelligence technology such as semantic web, knowledge map, natural language processing, etc., this paper studies the key technologies of equipment intelligent service, and proposes a knowledge intelligent technology framework for transformer. This framework includes three components: unstructured text intelligent recognition and extraction, device centered device knowledge representation and storage, and device knowledge intelligent application.
Specific emitter identification based on CNN
Authors: Hou Keke , Li Nan
Published: July 2021

Specific emitter identification is one of the important technologies of electronic countermeasures. The convolutional neural network (CNN) has a strong ability to process image classification. To solve the problem that the bispectral feature of the radiation source does not perform well in the specific emitter identification, this paper proposes a method of combining the two-dimensional bispectrum of the radiation source and CNN. In order to test the performance of the method, this article designed a semi-physical system to collect the radiation source signal. It is verified by experiments that this method has a 92.4% correct rate for identifying different radiation source signals. Compared with other algorithms that combine bispectral features, the proposed method has advantages in accuracy and complexity.
Star Sensor Calibration Using Fine Guidance Sensor Information for Installation Errors
Authors: Gao Jingwei , Zhang Yang , Gao Jingmin , Zhang Kebei , Feng Qingjuan , Guo Miao
Published: July 2021

To correct installation errors of star sensors, we propose an error calibration method based on the measurement information from fine guidance sensors (FGS). This work established an extended Kalman filter model by using the measurement information of FGS as the observation to estimate position errors. Simulation experiments are presented to assess the effectiveness of the proposed star sensor calibration technique, and the results demonstrate the improved error estimation accuracy.
Design of High Gain Wearable Antenna Based on Wireless Body Area Network Communications
Authors: Wang Yan , Bao Jianqiang , Tian Yanwei , Wang Zhao , Li Na
Published: July 2021

This paper presents a wearable antenna for Wireless Body Area Network communication. A 3×3 array artificial magnetic conductor structure (AMC) is loaded at the bottom of the antenna to reduce the backward radiation and improve the antenna gain. The simulated results show that the antenna can completely meet the working requirements in the bent state. After the addition of AMC array, the maximum gain reaches 7.53 dB, and the SAR value of human tissue can be reduced by about 94%. In addition, we have also processed and tested the antenna. The measured results are in good agreement with the simulated results, and its working bandwidth includes the low-frequency band of the ISM frequency band for WBAN communication, which can meet the working requirements of the antenna.
Influence evaluation of UAV inlet on electromagnetic scattering and time-frequency characteristics
Authors: Sun Xumin
Published: July 2021

An analytical method for electromagnetic scattering characteristics of complex unmanned aerial vehicle targets by using hybrid multilevel fast multipole algorithm (MLFMA)-physical optics (PO) and short-time fourier transformation (STFT) is proposed in this paper. By constructing accurate electromagnetic models of unmanned aerial vehicle (UAV) target with inlet, the aspect and polarization characteristics of radar cross section (RCS) and time-frequency representation (TFR) are studied. To validate the influence of the inlet, the monostatic and bistatic RCS at specific angles, RCS statistical characteristics and TFR correlation are simulated and compared. It is concluded that the inlet should be sufficiently considered to calculate the accurate scattering characteristics.