bluuebunny/crossref_metadata_2025 huggingface dataset:
Collagen type I promotes osteogenic differentiation of amniotic membrane-derived mesenchymal stromal cells in basal and induction media
Authors: Akhir Haselamirrah Mohd , Teoh Peik Lin
Published: November 2020

Collagen has been widely shown to promote osteogenesis of bone marrow mesenchymal stromal cells (BM-MSCs). Due to the invasive procedure of obtaining BM-MSCs, MSCs from other tissues have emerged as a promising alternative for regenerative therapy. MSCs originated from different sources, exhibiting different differentiation potentials. Therefore, the applicability of collagen type I (COL), combining with amniotic membrane (AM)-MSCs was examined through proliferation and differentiation assays together with the expression of surface markers and genes associated with stemness and differentiation under basal or induction conditions. No increase in cell growth was observed because AM-MSCs might be directed toward spontaneous osteogenesis. This was evidenced by the calcium deposition and elevated expression of osteogenic genes when AM-MSCs were cultured in collagen plate with basal media. Under the osteogenic condition, reciprocal expression of OCN and CEBPA suggested a shift toward adipogenesis. Surprisingly, adipogenic genes were not elevated upon adipogenic induction, although oil droplets deposition was observed. In conclusion, our findings demonstrated that collagen causes spontaneous osteogenesis in AM-MSCs. However, the presence of exogenous inductors could shift the direction of adipo-osteogenic gene regulatory network modulated by collagen.
Red algae natural products for prevention of lipopolysaccharides (LPS)-induced liver and kidney inflammation and injuries
Authors: Nabil-Adam Asmaa , Shreadah Mohamed A.
Published: November 2020

Background: The liver and kidney inflammation due to bacterial infection is one of the most common pathological problems leading to tissue damage or disease. In many liver and kidney disorders, which represent serious global health burden with a high economic cost, oxidative stress-related inflammation and apoptosis are important pathogenic components, finally resulting in acute liver and/or kidney failure. Erythropoietin and its analogues are well known to influence the interaction between apoptosis and inflammation in liver and kidney. Objective: The aim of the present study is to investigate and clarify the effect of Galaxaura oblongata (G. oblongata) red algae on lipopolysaccharides (LPS)-induced acute liver and kidney injury of mice with endotoxemia and associated molecular mechanism from inflammation, apoptosis and oxidative stress levels. Results: The current study cleared out that treatment of rats with the G. oblongata extract prior to LPS injection significantly lowered serum cytokines, including NF-κB, MPO and LPO, and improved liver apoptosis through suppressing protein tyrosine kinase signaling pathway, and that may be due to antibacterial activity as well antioxidant capacity of G. oblongata extract. Conclusion: The present study was cleared out the possibility of administration of G. oblongata red algae as a multi products source for biotechnological, medical, nutraceutical and pharmaceutical applications due to highly antioxidant and anti-inflammatory capacities even although more investigations are required for separating, purifying and characterizing these bioactive compounds.
Screening and validation of differentially expressed microRNAs and target genes in hypertensive mice induced by cytomegalovirus infection
Authors: Shi YunZhong , Xi DongMei , Zhang XiaoNi , Huang Zhen , Tang Na , Liu YongMin , Wang LaMei , Tang Yan , Zhong Hua , He Fang
Published: November 2020

Introduction: Multiple studies have suggested an association between cytomegalovirus (CMV) infection and essential hypertension (EH). MicroRNAs (miRNAs) play a critical role in the development of EH by regulating the expression of specific target genes. However, little is known about the role of miRNAs in CMV-induced EH. In the present study, we compared the miRNA expression profiles of samples from normal and murine cytomegalovirus (MCMV)-infected C57BL/6 mice using high-throughput sequencing analysis. Methods: We collected the thoracic aorta, heart tissues, and peripheral blood from 20 normal mice and 20 MCMV-infected mice. We identified differentially expressed miRNAs in the peripheral blood samples and predicted their target genes using bioinformatics tools. We then experimentally validated them using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and the target genes with double luciferase reporter gene assay. Results: We found 118 differentially expressed miRNAs, among which 9 miRNAs were identified as potential MCMV infection-induced hypertension regulators. We then validated the expression of two candidate miRNAs, mmu-miR-1929-3p and mcmv-miR-m01-4-5p, using qRT-PCR. Furthermore, the dual-luciferase reporter gene assay revealed that the 3′-untranslated region (UTR) of endothelin A receptor (Ednra) messenger RNA (mRNA) contained a binding site for mmu-miR-1929-3p. Collectively, our data suggest that MCMV infection can raise the blood pressure and reduce mmu-miR-1929-3p expression in C57BL/6 mice. Moreover, we found that mmu-miR-1929-3p targets the 3′-UTR of the Ednra mRNA. Conclusion: This novel regulatory axis could aid the development of new approaches for the clinical prevention and control of EH.
Immune-associated biomarkers for early diagnosis of Parkinson’s disease based on hematological lncRNA–mRNA co-expression
Authors: Lei Kecheng , Zhang Liwen , He Yijing , Sun Hui , Tong Weifang , Xu Yichun , Jin Lingjing
Published: November 2020

Early stage diagnosis of Parkinson’s disease (PD) is challenging without significant motor symptoms. The identification of effective molecular biomarkers as a hematological indication of PD may help improve the diagnostic timelines and accuracy. In the present paper, we analyzed and compared the blood samples of PD and control (CTR) patients to identify the disease-related changes and determine the putative biomarkers for PD diagnosis. Based on the RNA sequencing analysis, differentially expressed genes (DEGs) were identified, and the co-expression network of DEGs was constructed using the weighted gene correlation network analysis (WGCNA). The analysis leads to the identification of 87 genes that were exclusively regulated in the PD group, whereas 66 genes were significantly increased and 21 genes were significantly decreased in contrast with the control group. The results indicate that the core lncRNA–mRNA co-expression network greatly changes the immune response in PD patients. Specifically, the results showed that Prader Willi Angelman Region RNA6 (PWAR6), LINC00861, AC83843.1, IRF family, IFIT family and calcium/calmodulin-dependent protein kinase IV (CaMK4) may play important roles in the immune system of PD. Based on the findings from the present study, future research aims at identifying novel therapeutic strategies for PD.
RNA matchmaking in chromatin regulation
Authors: Wu Stephen K. , Roberts Justin T. , Balas Maggie M. , Johnson Aaron M.
Published: November 2020

Beyond being the product of gene expression, RNA can also influence the regulation of chromatin. The majority of the human genome has the capacity to be transcribed and the majority of the non-protein-coding transcripts made by RNA Polymerase II are enriched in the nucleus. Many chromatin regulators can bind to these ncRNAs in the nucleus; in some cases, there are clear examples of direct RNA-mediated chromatin regulation mechanisms stemming from these interactions, while others have yet to be determined. Recent studies have highlighted examples of chromatin regulation via RNA matchmaking, a term we use broadly here to describe intermolecular base-pairing interactions between one RNA molecule and an RNA or DNA match. This review provides examples of RNA matchmaking that regulates chromatin processes and summarizes the technical approaches used to capture these events.
Post-transcriptional control of mitochondrial protein composition in changing environmental conditions
Authors: Tsuboi Tatsuhisa , Leff Jordan , Zid Brian M.
Published: November 2020

In fluctuating environmental conditions, organisms must modulate their bioenergetic production in order to maintain cellular homeostasis for optimal fitness. Mitochondria are hubs for metabolite and energy generation. Mitochondria are also highly dynamic in their function: modulating their composition, size, density, and the network-like architecture in relation to the metabolic demands of the cell. Here, we review the recent research on the post-transcriptional regulation of mitochondrial composition focusing on mRNA localization, mRNA translation, protein import, and the role that dynamic mitochondrial structure may have on these gene expression processes. As mitochondrial structure and function has been shown to be very important for age-related processes, including cancer, metabolic disorders, and neurodegeneration, understanding how mitochondrial composition can be affected in fluctuating conditions can lead to new therapeutic directions to pursue.
Coexistence of CH4, CO2, and H2O in exoplanet atmospheres
Authors: Woitke P. , Herbort O. , Helling Ch. , Stüeken E. , Dominik M. , Barth P. , Samra D.
Published: November 2020

We propose a classification of exoplanet atmospheres based on their H, C, O, and N element abundances below about 600 K. Chemical equilibrium models were run for all combinations of H, C, O, and N abundances, and three types of solutions were found, which are robust against variations of temperature, pressure, and nitrogen abundance. Type A atmospheres contain H2O, CH4, NH3, and either H2 or N2, but only traces of CO2 and O2. Type B atmospheres contain O2, H2O, CO2, and N2, but only traces of CH4, NH3, and H2. Type C atmospheres contain H2O, CO2, CH4, and N2, but only traces of NH3, H2, and O2. Other molecules are only present in ppb or ppm concentrations in chemical equilibrium, depending on temperature. Type C atmospheres are not found in the Solar System, where atmospheres are generally cold enough for water to condense, but exoplanets may well host such atmospheres. Our models show that graphite (soot) clouds can occur in type C atmospheres in addition to water clouds, which can occur in all types of atmospheres. Full-equilibrium condensation models show that the outgassing from warm rock can naturally provide type C atmospheres. We conclude that type C atmospheres, if they exist, would lead to false positive detections of biosignatures in exoplanets when considering the coexistence of CH4 and CO2, and suggest other, more robust non-equilibrium markers.
Fast flaring observed from XMMU J053108.3−690923 by eROSITA: a supergiant fast X-ray transient in the Large Magellanic Cloud
Authors: Maitra C. , Haberl F. , Vasilopoulos G. , Ducci L. , Dennerl K. , Carpano S.
Published: November 2020

Context. Supergiant fast X-ray transients (SFXTs) are a peculiar class of supergiant high-mass X-ray binary (HMXB) systems characterised by extreme variability in the X-ray domain. In current models, this is mainly attributed to the clumpy nature of the stellar wind coupled with gating mechanisms involving the spin and magnetic field of the neutron star.

Aims. We studied the X-ray properties of the supergiant HMXB XMMU J053108.3−690923 in the Large Magellanic Cloud to understand its nature.

Methods. We performed a detailed temporal and spectral analysis of the eROSITA and XMM-Newton data of XMMU J053108.3−690923.

Results. We confirm the putative pulsations previously reported for the source with high confidence, certifying its nature as a neutron star in orbit with a supergiant companion. We identify the extremely variable nature of the source in the form of flares seen in the eROSITA light curves. The source flux exhibits a total dynamic range of more than three orders of magnitude, which confirms its nature as an SFXT, and is the first such direct evidence from a HMXB outside our Galaxy exhibiting a very high dynamic range in luminosity as well as a fast flaring behaviour. We detect changes in the hardness ratio during the flaring intervals where the hardness ratio reaches its minimum during the peak of the flare and increases steeply shortly afterwards. This is also supported by the results of the spectral analysis carried out at the peak and off-flare intervals. This scenario is consistent with the presence of dense structures in the supergiant wind of XMMU J053108.3−690923 where the clumpy medium becomes photoionised at the peak of the flare leading to a drop in the photo-electric absorption. Further, we provide an estimate of the clumpiness of the medium and the magnetic field of the neutron star assuming a spin equilibrium condition.
Biomimetic Mechanism of Action of Fluoridated Toothpaste Containing Proprietary REFIX Technology on the Remineralization and Repair of Demineralized Dental Tissues: An In Vitro Study
Authors: Vilhena Fabiano Vieira , de Oliveira Sonia Mariza Luiz , Matochek Marcelo Henrick Maia , Tomaz Pedro Luiz Santos , Oliveira Thales de Sá , D’Alpino Paulo Henrique Perlatti
Published: November 2020

Objectives This in vitro study aimed to characterize the mineral content and surface and cross-sectional morphology of enamel and dentin tissues treated with a 1450 ppm fluoride-containing toothpaste with REFIX technology.

Materials and Methods Bovine enamel blocks (n = 5) were obtained (4 × 4 × 6 mm), demineralized (artificial caries lesion), and treated (pH cycling and brushing with the toothpaste). During the pH cycling, which lasted for 7 days (demineralization and remineralization took 6 and 18 hours, respectively), the enamel was brushed for 5 minutes using an electric toothbrush before being immersed in a remineralizing solution. The dentin blocks were acid-etched for 2 minutes (0.05 M citric acid, pH 1.8) to expose the dentinal tubules (n = 5). Morphological analysis of the dentin was performed immediately and after 7 days of brushing with the dentifrice, and compared with the control group. The specimens were then cross-sectioned. The surface and cross-sectional micromorphology were assessed using scanning electron microscopy (SEM). The elemental analyses (weight%) were determined with an energy-dispersive X-ray spectroscopy (EDS).

Results The toothpaste with REFIX technology remineralized and repaired the surface enamel effectively. The elemental analysis also demonstrated that treating the enamel with the toothpaste formed a silicon-enriched mineral layer on the enamel surface. Elemental analysis of the enamel cross-sections showed that the toothpaste induced a mineral change. The results were also consistent in the dentin, where the dentinal tubules were progressively occluded until there was complete occlusion after 7 days.

Conclusions We prove the biomimetic mechanism of action of fluoridated toothpaste containing proprietary REFIX technology for obtaining silicon-enriched, remineralized and repaired dental tissues.
Cervical Cordotomy in Terminal Cancer: Pain Relieving in Oncological Treatment
Authors: Seba Maria Clara Cardoso , Bernardo Henrique Nicola Santo Antonio , Sarturi Natally Marques Santiago , Rossi Thania Gonzalez , Oliveira Newton Maciel de , Aguiar Paulo Henrique Pires de
Published: November 2020

Cordotomy consists in the discontinuation of the lateral spinothalamic tract (LST) in the anterolateral quadrant of the spinal cord, which aims to reduce the transference of nociceptive information in the dorsal horn of the gray matter of the spinal cord to the somatosensory cortex. The main indication is for patients with terminal cancer that have a low life expectancy. It improves the quality of life by relieving pain. The results are promising and the pain relief rate varies between 69 and 100%. Generally speaking, the complications are mostly temporary and not remarkable.
Ophthalmology Program Directors' Perspectives on the Impact of the United States Medical Licensing Examination Step 1 Change to Pass-Fail Scoring
Authors: Cui David , Scott Ingrid U. , Wingert Heidi Luise
Published: November 2020

Purpose This article investigates the perspectives of ophthalmology residency program directors (PDs) regarding the impact of the United States Medical Licensing Examination (USMLE) Step 1 change from graded to pass-fail scoring on ophthalmology resident selection and medical education.

Methods The PDs of all United States ophthalmology residency programs accredited by the Accreditation Council for Graduate Medical Education were identified using a public, online database. An anonymous web-based survey constructed using REDCap was emailed to each PD in February 2020.

Results Surveys were completed by 64 (54.2%) PDs, with the majority (81.2%) disagreeing with the change to pass-fail scoring. The majority of PDs believe this change will negatively impact the ability to evaluate residency applicants (92.1%) and achieve a fair and meritocratic match process (76.6%), and will decrease medical students' basic science knowledge (75.0%). The factors identified most frequently by PDs as becoming more important in evaluating residency applicants as a result of the Step 1 scoring change include clerkship grades (90.6%), USMLE Step 2 Clinical Knowledge score (84.4%), and a rotation in the PD's department (79.7%). The majority of PDs believe the Step 1 grading change to pass-fail will benefit applicants from elite medical schools (60.9%), and disadvantage applicants from nonelite allopathic schools (82.8%), international medical graduate applicants (76.6%), and osteopathic applicants (54.7%).

Conclusion The majority of ophthalmology PDs disagree with the change in USMLE Step 1 scoring from graded to pass-fail and believe this change will negatively impact the ability to evaluate residency applicants and achieve a fair and meritocratic match process, and will decrease medical students' basic science knowledge.
Clinical Performance of Bulk-Fill Resin Composite Restorations Using the United States Public Health Service and Federation Dentaire Internationale Criteria: A 12-Month Randomized Clinical Trial
Authors: Durão Márcia de Almeida , Andrade Ana Karina Maciel de , Santos Maria do Carmo Moreira da Silva , Montes Marcos Antônio Japiassú Resende , Monteiro Gabriela Queiroz de Melo
Published: November 2020

Objective This study was aimed to compare the 12-month clinical performance of two full-body bulk-fill resin composites Filtek bulk fill/3M ESPE (FBF) and Tetric EvoCeram bulk fill/Ivoclar Vivadent (TBF) and a conventional microhybrid resin composite Filtek Z250/3M ESPE (Z250) using the modified the United States Public Health Service (USPHS) and Federation Dentaire Internationale (FDI) criteria. Also, the agreement between the two evaluation criteria was evaluated at baseline and after 12 months of follow-up.

Materials and Methods A total of 138 class I and II restorations were placed in posterior teeth (split-mouth design) of 46 volunteers following manufacturer’s instructions and bonded with a self-etching bonding agent (Clear fill SE Bond/Kuraray). The restorations were evaluated at baseline and after 12 months of follow-up by three previously calibrated dentists (Cohen’s K = 0.84).

Statistical Analysis Fisher’s exact test and Pearson’s Chi-squared test were used to evaluating the homogeneity of distribution of the clinical characteristics. Friedman’s test was applied to evaluate differences among the resin composites. The results obtained for the USPHS and FDI criteria at the different observation times were compared using the Wilcoxon test. A level of significance of 0.05 was adopted for all tests.

Results After 12 months (recall rate, 78.3%, n = 36 patients), the overall success rate was 99.07% for both criteria. Only one failed restoration (0.93%) was detected for each system during follow-up in the TBF group.

Conclusion The bulk-fill resin composites showed satisfactory clinical performance compared with conventional resin composite after 12 months. The percentage of the acceptable scores was significantly higher for the USPHS criteria, due to discrepancies in the score description for each criterion.
Epidemiological Profile of Surgically-Treated Peripheral-Nerve Diseases
Authors: Fuzari Helen Kerlen Bastos , Andrade Armèle Dornelas de , Souza Renata Janaina Pereira de , Bernardino Silvya Nery , Souza Fernando Henrique Moraes de , Sarmento Antonio , Oliveira Daniella Araújo de
Published: November 2020

Objective To outline the epidemiological profile of surgical patients treated at the peripheral-nerve outpatient clinic of a public hospital in the state of Pernambuco, Brazil, from 2008 (the year this service was implemented in the hospital ) to 2016.

Material and Methods A cross-sectional study with data collection from the medical records. A descriptive analysis was performed with the qualitative variables presented as relative and absolute frequencies, and the quantitative variables, as means and standard deviations. The studied variables were gender, age, diagnosis, and surgical techniques.

Results In total, 506 medical records were analyzed. Of these, 269 were of male patients (53%), and 238 were of female patients (46%). The age of the sample ranged from 5 to 84 years (41 ± 14 years). The most prevalent diagnoses were: carpal tunnel syndrome (38.9%) followed by traumatic brachial plexus injury (33.2%). The first diagnosis was more frequent among women, while the second, among men. This collaborates with the predominant findings of upper-limb lesions (91%), in which men accounted for 52,75% (244) and women, for 47,25% (217).

Conclusion The present study provided relevant information regarding the reality of peripheral-nerve surgeries performed at a public hospital in the state of Pernambuco, Brazil. Public health issues increasingly require the continuity of public policies and government incentive.
Jugular Foramen's Paraganglioma in a Patient with Von Hippel-Lindau Disease: Case Report
Authors: Pereira Barbara Casalecchi , Aznar Julia Dallana , Zambon Amélia Limongi , Melo Diogo Fabricio Coelho de , Silva Marcelo Nery
Published: November 2020

Glomus jugular tumors, also known as paragangliomas (PGLs), are rare and related to several clinical syndromes described. These are located in the carotid body, the jugular glomus, the tympanic glomus and the vagal glomus. The symptoms are directly related to the site of involvement and infiltration. These lesions have slow growth, are generally benign and hypervascularized, have a peak incidence between the age of 30 to 50 years old; however, when associated with hereditary syndromes, they tend to occur a decade earlier. Several familial hereditary syndromes are associated with PGLs, including Von Hippel-Lindau disease (VHL) in < 10% of the cases. The diagnosis and staging of PGLs are based on imaging and functional exams (bone window computed tomography [CT] with a “ground moth” pattern and magnetic resonance imaging (MRI) with a “salt and pepper” pattern). The cerebral angiography is a prerequisite in patients with extremely vascularized lesions, whose preoperative embolization is necessary. The histopathological finding of cell clusters called “Zellballen” is a characteristic of PGLs. Regarding the jugular foramen, the combination of two or three surgical approaches may be necessary: (1) lateral group, approaches through the mastoid; (2) posterior group, through the retrosigmoid access and its variants; and (3) anterior group, centered on the tympanic and petrous bone. In the present paper, we report a case of PGL of the jugular foramen operated on a young female patient who underwent a surgery with a diagnosis of Von Hippel-Lindau Disease (VHL) at the Neurosurgery Service of the Hospital Heliópolis, São Paulo, state of São Paulo, Brazil in 2018, by the lateral and posterior combined route.
Minimally Invasive Mini-orbitozygomatic Approach for Clipping an Anterior Communicating Artery Aneurysm: Virtual Reality Surgical Planning
Authors: González Romo Nicolás , Ravera Zunino Franco
Published: November 2020

Virtual reality (VR) has increasingly been implemented in neurosurgical practice. A patient with an unruptured anterior communicating artery (AcoA) aneurysm was referred to our institution. Imaging data from computed tomography angiography (CTA) was used to create a patient specific 3D model of vascular and skull base anatomy, and then processed to a VR compatible environment. Minimally invasive approaches (mini-pterional, supraorbital and mini-orbitozygomatic) were simulated and assessed for adequate vascular exposure in VR. Using an eyebrow approach, a mini-orbitozygomatic approach was performed, with clip exclusion of the aneurysm from the circulation. The step-by-step process of VR planning is outlined, and the advantages and disadvantages for the neurosurgeon of this technology are reviewed.
Multifocal Pseudotumorous Form of Neuroparacoccidioidomycosis in an Immunocompetent Patient: A Clinicopathological Review Based on a Case Report
Authors: Cambruzzi Eduardo , Pêgas Karla Lais , Nascimento Gabriella Bezerra Cortês , Silva José Nathan Andrade Muller da , Zandoná Natália Brandelli , Kus William Pegoraro , Schiavo Felipe Lourezon , Santos Samir Cezimbra dos
Published: November 2020

Neuroparacoccidiodimycosis (NPDM) is an uncommon granulomatous disease, which more frequently affects immunocompromised male patients over 30 years of age in the course of chronic lung disease. Paracoccidioides brasiliensis (PB) is an endemic fungus in Brazil, and grows as thick-walled yeast (with round to oval bodies) measuring 10 µm to 60 µm in diameter. Neuroparacoccidiodimycosi may develop many years after transmission and/or primary lung involvement. The authors describe a case of NPDM affecting a male patient, 52 years of age, farmer, heavy smoker, with clinical complaint of headache, asthenia, seizures, and prostration in the previous nine months. Upon physical examination, the patient presented regular general condition, without other relevant physical alterations. Computed tomography (CT) showed multiple bilateral pulmonary nodules associated to enlargement of the mediastinal lymph node. Magnetic resonance imaging (MRI) and CT scans of the central nervous system showed six heterogeneous nodular lesions compromising the frontal and parietal lobes, the largest one measuring 3.8 × 3.2 × 3.2 cm. The hypothesis of a neoplastic process compromising the lung and brain was considered. A biopsy of the mediastinal lymph node showed epithelioid granulomas, which exhibited round, thin-walled fungal structures in Grocott silver stain. The stereotactic biopsy of the frontal lesion was constituted by necrotic tissue admixed with some round to oval, thin-walled fungi measuring 10 µm to 60 µm, compatible with PB (identified on Grocott silver stain/confirmed in culture). The diagnosis of NPDM was then established. The employed therapeutic regimen was intravenous amphotericin B, itraconazole, and sulfamethoxazole-trimetropin. After ninety days of clinical follow-up, no episodes of seizures/neurological deficits were identified, and a marked decrease in the number and size of the lung and brain lesions were found.
An Unusual Dermoid Cyst of the Pineal Region: Case report in a Child
Authors: Jamali Mohammad , Ahrari Iman , Saffarrian Arash , Eghbal Keyvan , Rakhsha Abbas , Ghahramani Sulmaz
Published: November 2020

Introduction The pineal gland is a common location for intracranial germ cells, but dermoids are not commonly observed in this area. In the present paper, we discuss the clinical and radiological features as well as the treatment and outcome of this cyst in a 6-year- old child with a pineal dermoid cyst.

Case Presentation The patient presented with chronic headache 6 months before admission in 2018. On the first admission, an enhanced lesion with a small cyst was detected in brain imaging. Magnetic resonance imaging (MRI) of the brain at follow-up (2 months after the first presentation) showed enlargement of the cyst size with compression on the adjacent structures. Radical excision of the tumor was performed after the endoscopic biopsy due to pressure exerted on the adjacent structures.

Conclusion Dermoid cyst should be considered as a differential diagnosis for enhanced lesions of the pineal region.
Reliability of the Mangled Extremity Severity Score in the Management of Peripheral Vascular Injuries in Children: A Retrospective Review
Authors: Mousa Ahmed , Zakaria Ossama M. , Elkalla Mai A. , Abdelsattar Lotfy A. , Al-Game'a Hamad
Published: November 2020

This study was aimed to evaluate different management modalities for peripheral vascular trauma in children, with the aid of the Mangled Extremity Severity Score (MESS). A single-center retrospective analysis took place between 2010 and 2017 at University Hospitals, having emergencies and critical care centers. Different types of vascular repair were adopted by skillful vascular experts and highly trained pediatric surgeons. Patients were divided into three different age groups. Group I included those children between 5 and 10 years; group II involved pediatrics between 11 and 15 years; while children between 16 and 21 years participated in group III. We recruited 183 children with peripheral vascular injuries. They were 87% males and 13% females, with the mean age of 14.72 ± 04. Arteriorrhaphy was performed in 32%; end-to-end anastomosis and natural vein graft were adopted in 18% and 29% respectively. On the other hand, 20% underwent bypass surgery. The age groups I and II are highly susceptible to penetrating trauma (p = 0.001), while patients with an extreme age (i.e., group III) are more susceptible to blunt injury (p = 0.001). The MESS has a significant correlation to both age groups I and II (p = 0.001). Vein patch angioplasty and end-to-end primary repair should be adopted as the main treatment options for the repair of extremity vascular injuries in children. Moreover, other treatment modalities, such as repair with autologous vein graft/bypass surgery, may be adopted whenever possible. They are cost-effective, reliable, and simple techniques with fewer postoperative complication, especially in poor/limited resources.
The Early Impact of COVID-19 on Ophthalmology Resident Training and Wellness
Authors: Woodfin Michael , Bojikian Karine D. , Taravati Parisa , Ding Leona , Lee Michele D. , Feng Shu
Published: November 2020

Objective The aim of this article is to assess the initial impact of the coronavirus disease 2019 (COVID-19) pandemic on ophthalmology resident training and wellness.

Design Online national survey of ophthalmology residents distributed by residency program directors and education coordinators of participating programs.

Setting US ophthalmology residency programs during the COVID-19 pandemic (May 20th, 2020 to June 10th, 2020).

Participants Ophthalmology residents enrolled in the US residency programs currently in postgraduate years two through four of training.

Results Two-hundred thirty-six of 785 (30.1%) residents responded to the survey. One-hundred eighteen of 234 (50.4%) residents reported exposure to known COVID-19 positive patients, and of those exposed, 44 of 118 (37.2%) felt that they did not have adequate personal protective equipment. One-hundred ninety-five of 233 (83.7%) residents reported a decrease in primary surgical cases during the pandemic, with 68 (29.2%) reporting a loss of more than 50 primary cases. One-hundred sixty-four of 234 (70.1%) residents were concerned that the pandemic would negatively impact their surgical skills beyond residency, and 15% reported that they were more likely to pursue fellowship due to the pandemic. 31.0% of residents met criteria of burnout, 9.1% were depressed, and 13.4% had generalized anxiety. Concerns about COVID-19 infection were correlated with increased anxiety and burnout during the pandemic.

Conclusions The COVID-19 pandemic has decreased resident surgical and clinical volumes and has negatively impacted ophthalmology residency training. Residents with increased concern for contracting COVID-19 and those actively engaged in a job search had significantly higher odds of increased anxiety.
Value chain approaches to reducing policy spillovers on international business
Authors: Findlay Christopher , Hoekman Bernard
Published: November 2020

Government policy can add to the costs of doing international business. It can distort the construction of and raise the costs of operation of global value chains (GVCs), to the detriment of the participating economies. Given rising technological and market-driven headwinds confronting GVCs, countries seeking to attract GVC activities have greater incentives to identify and address policies that negatively affect international business investment. Cooperation of businesses with regulators, analysts, and researchers has the scope to develop better policy. This paper suggests principles for the design and operation of such cooperation, drawing on the experience with multi-stakeholder value chain partnerships and the policy responses to the 2020 COVID-19 pandemic.
The Inception of Literary Criticism in Early Modern Pashto Writings
Authors: Pelevin Mikhail
Published: November 2020

The article overviews the earliest Pashto texts, mostly poetic, in which the incipient forms of literary criticism can be traced as authorial self-reflections related in Persian classics to the self-praise genre (fakhriyya) and explanations of reasons for composing works (sabab-i taʾlīf). Under close examination are the seventeenth century verses of the poets affiliated with the Roshānī religious community and the writings of Khushḥāl Khān Khaṫak (d. 1689). Analyzed texts prove that through the rudimentary discourse on a variety of literary criticism topics, Pashtun authors of early modern times declared and justified the presence of emerging literature in Pashto within the Persophone cultural space of Mughal India, articulating simultaneously their commitment to the proliferation of literacy and Islamic book culture among their countrymen.
Recovery of coefficients for a weighted p-Laplacian perturbed by a linear second order term
Authors: Cârstea Cătălin I , Kar Manas
Published: November 2020

This paper considers the inverse boundary value problem for the equation ∇ ⋅ (σ∇u + a|∇u|
p−2∇u) = 0. We give a procedure for the recovery of the coefficients σ and a from the corresponding Dirichlet-to-Neumann map, under suitable regularity and ellipticity assumptions.
Feasibility study of a micro-electro-mechanical-systems threshold-pressure sensor based on parametric resonance: experimental and theoretical investigations
Authors: Pallay Mark , Daeichin Meysam , Towfighian Shahrzad
Published: November 2020

A tunable threshold pressure sensor based on parametric resonance of a microbeam subjected to electrostatic levitation is proposed. Parametric excitation can trigger a large amplitude vibration at twice the natural frequency if the magnitude of the driving force is large enough to overcome energy loss mechanisms in the system such as squeeze film damping. This causes a temporarily unstable response with a significant gain in oscillation amplitude over time until it is eventually capped by nonlinearities in the force or material or geometric properties. The instability divides the frequency region into two regions: distinct responses bounded by the system non-linearity, and trivial responses with very low oscillation amplitudes. It is shown experimentally that the appearance of parametric resonance depends on the pressure, which influences the amount of energy loss from squeeze film damping. Therefore, the distinct difference in the vibration amplitude can be used to detect when the pressure passes a threshold level. The activation of parametric resonance also depends on the amplitude of the driving force (

V

ac

). This voltage amplitude can be set to trigger parametric resonance when the pressure drops below a predetermined threshold. A reduced-order model is developed using the Euler–Bernoulli beam theory to elucidate the non-linear dynamics of the system. The simulation results from the mathematical model are in good agreement with the experimental data. The advantages of the proposed sensor over pull-in based sensors are its reliability and improved resolution from a large signal-to-noise ratio.
Quantum secrecy in thermal states III
Authors: Ghesquière Anne , Varcoe Benjamin T H
Published: November 2020

In this paper we expanded the security of a central broadcast protocol using thermal states to the case in which the eavesdropper controls the source. Quantum secrecy in a continuous variable central broadcast scheme is guaranteed by the quantum correlations present in thermal states arising from the Hanbury Brown and Twiss effect. This work allows for a method of key exchange in which two parties can agree a key as long as both can detect the same source and they are within the spatial coherence length of the source. This is important because it allows quantum secure key exchange with only minimal changes to existing infrastructure.
Short-time emission of higher-angular-momentum photons by atomic transitions
Authors: Lei Meng Lok , Debierre Vincent
Published: November 2020

The short-time regime of spontaneous light emission by few-electron ions is examined in detail, with a specific emphasis on the angular momentum of the emitted light. It is found that, in general, photons carrying a higher angular momentum are emitted with important probabilities, at short times, in transitions that are not of the electric dipole type. The probability of emission of such photons is found to be parametrically non-negligible in this time regime, and even numerically dominant for some cases. It is also found that, in all time regimes, the emission of electric 2
n+1-pole fields is typically numerically dominant over the emission of magnetic 2
n
-pole fields by many orders of magnitude. These results refine and deepen our understanding of the emission of angular momentum-carrying light by simple atomic systems.
Hyperfine splitting and lifetime of the positronium lowest level in a strong electric field
Authors: Milošević M Z , Bunjac A , Popović D B , Simonović N S
Published: November 2020

When placed in an external electric field, positronium, which already has a finite lifetime due to annihilation, becomes additionally unstable due to field-induced ionization. Calculations of the ionization rate using ab initio methods show that, compared to annihilation, it becomes dominant in the range of field strengths belonging to over-the-barrier ionization (OBI) regime. On the other hand, the hyperfine splitting of the positronium lowest level decreases in the tunnelling domain, taking at the beginning of the OBI domain a value that is about 20% lower than the field-free value. As the field strength increases further, this splitting varies rather slowly, but here an additional splitting of triplet levels occurs, whose rate is comparable to this variation. Finally, it is demonstrated that the lowest energy levels and ionization rates for the hydrogen atom and positronium, determined within the gross structure, are related to scaling transformations.
Experimental re-evaluation of proton penetration ranges in GaAs and InGaP
Authors: Yaccuzzi E , Di Napoli S , Di Liscia E J , Suárez S , Alurralde M , Strittmatter A , Pla J , Giudici P
Published: November 2020

Multijunction solar cells based on InGaP and GaAs materials are currently the state of the art for space applications due to their high efficiencies. However, space is a hazardous environment with different energetic particles that degrade the solar cell efficiency, hence decreasing the satellite lifetime. To gain insight in the behaviour of the solar cells under particle bombardment, we study the effect of radiation on InGaP and GaAs layers, constituent materials of III–V solar cells. By means of photoluminescence and Raman spectroscopy we investigate changes of the optical parameters in the irradiated region, and compare the results with simulations obtained with the code Stopping and Ranges of Ions in Matter. The proton ranges obtained from experiments differ considerably from the predicted by the simulations in the case of InGaP. We demonstrate that this discrepancy increases monotonously with proton energy. We discuss the possible origin of the differences in terms of electronic orbitals and bonding structure of the simulated compound, and the implications in the design of solar cells for space applications.
A safe and efficient LIDAR-based navigation system for 4WS4WD mobile manipulators in manufacturing plants
Authors: Meng Jie , Wang Shuting , Xie Yuanlong , Li Gen , Zhang Xiaolong , Jiang Liquan , Liu Chao
Published: November 2020

The safe and efficient autonomous navigation of mobile manipulators is still challenging in harsh manufacturing environments with dynamic obstacles and narrow spaces. This paper addresses that challenge by proposing an industrial-grade LIDAR-based navigation system for four-wheel-steering and four-wheel-driving mobile manipulators and focuses on enhancing the system’s safety and efficiency in manufacturing plants. On one hand, using an efficient soft-evidence unscented distance filter, a robust localization method is presented to eliminate dynamic interference. The variation results of scan matching are ingeniously applied to formulate a practical localization-failure-detection strategy, therefore improving localization safety under confusing working conditions. On the other hand, an efficient path-graph-based trajectory-planning method is proposed, which can instantly generate a trajectory in a safe and effective search space. Considering the regional connectivity and movement characteristics of the 4WS4WD mobile manipulator, a novel path graph is designed to construct the search space. Even in a large-scale scenario, a robot can obtain the desired trajectory within 5 ms. Ultimately, some core modules, such as a safety module and a fault-tolerant control module are integrated to form a comprehensive navigation system. The simulated and real experimental results prove the excellent performance of our navigation system, which has been successfully applied in many real-world scenarios.
A low-cost apparatus to measure the Seebeck coefficient
Authors: Mulla Rafiq , Rabinal M K
Published: November 2020

In this paper, a very simple and low-cost setup design is described for the Seebeck coefficient measurement of the disc and rod-shaped specimens. The setup has been tested for its reliable working by measuring the Seebeck coefficients of standard samples; measured values match with the literature. The setup can be built with commonly available raw materials in a short time. The tool is portable and can be used as a testing tool or to demonstrate the thermoelectric effect in different materials.
Utilizing shared information between gradient-spoiled and RF-spoiled steady-state MRI signals
Authors: Sveinsson Bragi , Gold Garry E , Hargreaves Brian A , Yoon Daehyun
Published: November 2020

This work presents an analytical relationship between gradient-spoiled and RF-spoiled steady-state signals. The two echoes acquired in double-echo in steady-state scans are shown to lie on a line in the signal plane, where the two axes represent the amplitudes of each echo. The location along the line depends on the amount of spoiling and the diffusivity. The line terminates in a point corresponding to an RF-spoiled signal. In addition to the main contribution of demonstrating this signal relationship, we also include the secondary contribution of preliminary results from an example application of the relationship, in the form of a heuristic denoising method when both types of scans are performed. This is investigated in simulations, phantom scans, and in vivo scans. For the signal model, the main topic of this study, simulations confirmed its accuracy and explored its dependency on signal parameters and image noise. For the secondary topic of its preliminary application to reduce noise, simulations demonstrated the denoising method giving a reduction in noise-induced standard deviation of about 30%. The relative effect of the method on the signals is shown to depend on the slope of the described line, which is demonstrated to be zero at the Ernst angle. The phantom scans show a similar effect as the simulations. In vivo scans showed a slightly lower average improvement of about 28%.
Observation of a significant drop of electron density in cascaded arc argon plasma doped with oxygen gas using laser Thomson scattering
Authors: Wang Yong , Shi Jielin , Li Cong , Feng Chunlei , Ding Hongbin
Published: November 2020

In this work, the electron density (n
e) and electron temperature (T
e) of cascaded arc argon plasma regulated by adding electronegative oxygen gas have been investigated using laser Thomson scattering diagnostic technique. The results indicate that the addition of O2 gas causes a significant decrease of n
e, which drops from 1020 m−3 to 1017 m−3. This is mainly attributed to the dissociative recombination reaction between electrons and O2
+ molecular ions. Meanwhile, the formation of negative ions, O2
− and O−, consumes electrons and further makes n
e decrease. But, T
e remains nearly unchanged with the increase of O2 ratio from 0% to 10%. This is probably due to that the electron energy loss by the electron collisions with O2 molecules in the ground state balances the electron heating induced by the super-elastic collisions with the highly vibrational excited O2 molecules.
Simulation of the Ohkawa-mechanism- dominated current drive of electron cyclotron waves using linear and quasi-linear models
Authors: Zheng P W , He L H , Yin L , Lu X Q , Huang Q H , Zhong Y J , Deng S , Jiang X C , Gong X Y
Published: November 2020

Simulation on the Ohkawa-mechanism-dominated current drive (OKCD) of electron cyclotron (EC) waves is performed using TORAY-GA linear code, and the results are compared with those calculated by CQL3D quasi-linear code. It is found that the radial location of the OKCD profile is almost identical between the linear and the quasi-linear calculations. However, there are significant differences in the calculation of the total driven current

I

e
c

and the peak value of the driven current profile

j

e
c

p
e
a
k

between the two models. The

I

e
c

calculated by the CQL3D code is at least 1.4 times larger than the results from the TORAY-GA code. For the calculation of

j

e
c

p
e
a
k

, the results from CQL3D are at least 1.6 times larger than that calculated by TORAY-GA. With increasing electron temperature, the two models further enlarge the total driven current scaling factor

F
I

and the peak driven current density scaling factor

F
j

. This is mainly because the collision operator in TORAY-GA code adopts a high-speed model and does not retain the first-order Legendre expansion term for momentum conservation of electron self-collision. The quasi-linear effect does not have a significant influence on the total driven current of OKCD when the EC power level does not meet

P

r
f

MW

m

−
3

n
e

10

19

m

−
3

> 0.5. Therefore, in practical engineering, the TORAY-GA code can be used to calculate OKCD quickly and accurately by multiplying with appropriate scaling factors. The effect of momentum conservation is very important for OKCD and on-axis EC current drive (ECCD), but this effect is not important for off-axis ECCD. The results from this study show that the effects of electron trapping and the collision between resonant passing electrons and trapped electrons are responsible for the decrease in off-axis ECCD efficiency.