bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing third-harmonic generation by quasi bound states in continuum in silicon nanoparticle arrays
Authors: Du Qian , Chen Yi-Hang ,   Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
Published: June 2021

Subwavelength artificial structures of high refractive index dielectrics provide an effective way to control and manipulate light on a nanoscale by enhancing electric and magnetic fields. This kind of structure usually has low absorption loss, but its performance is also limited by radiation loss, which will reduce the efficiency of its nonlinear response. This problem can be solved by using bound states in the continuum (BICs). The BICs are a kind of unconventional state which is in continuous domain but remains localized. They exist within a light cone and have an infinite quality factor. By combining BICs with nonlinear optics, high-Q resonances from quasi-BICs are used to excite and enhance the nonlinear response. The simulation shows that when the symmetry of the unit cell of the silicon nanoparticle arrays is broken, the BIC become the quasi-BIC, and the transmission spectrum will produce a high-Q narrow resonance valley. The resonance has polarization dependence of electric field. With the change of pump wavelength, the third-harmonic generation (THG) intensity first increases and then decreases gradually. The pump wavelength changed by several nanometers can change THG intensity by at least one order of magnitude. When the pump wavelength is adjusted to the resonance wavelength, the nonlinearity is significantly enhanced as a result of the strong field localization. The THG intensity is highly sensitive to the variation of asymmetric parameters. Only a change of 75 nm will result in a decrease of THG intensity by at least one order of magnitude. There is a third-order relationship between pump power and THG power. For the proposed structure, the factors affecting the conversion efficiency of THG include pump power, pump wavelength, polarization angle of pump light, and asymmetry parameter. When the polarization direction of electric field is along the short axis of the structure and the pump light at resonance wavelength is vertically incident to the structure with an asymmetric parameter of 0.125, the conversion efficiency of THG can be increased to ～2.6 × 10–6 and the intensity of THG is increased by six orders of magnitude. The results are expected to be applied to designing the silicon-based optical nonlinear devices.
First-principles study of boron segregation in fcc-Fe grain boundaries and its influence on interface adhesive strength
Authors: Xu Pan-Pan , Han Pei-De , Zhang Zhu-Xia , Zhang Cai-Li , Dong Nan , Wang Jian ,   College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China,   College of Aeronautics and Astronautics, Taiyuan University of Technology, Jinzhong 030600, China
Published: June 2021

Boron, a commonly used microalloying element in steel, is distributed mainly at the grain boundary of stainless steel and plays an important role in regulating the mechanical, corrosion resistance and grain boundary structure of stainless steel. Owing to the small amount of boron added into the steel, it is difficult experimentally to detect the traces of boron segregation at the grain boundary, not to mention analyzing the structural characteristics of the boron segregation grain boundary. First-principles density functional theory (DFT) provides convenience in analyzing the existence mode and mechanism of boron in austenitic steel from the atomic level. Combining with the actual grain boundary structure types in austenitic stainless steel, Fcc-Fe Σ3(112), Σ5(210), Σ5(310), Σ9(114), Σ9(221) and Σ11(113) symmetric tilt grain boundaries are constructed based on DFT, and the segregation behaviors of boron atoms at the six grain boundaries are studied to reveal the segregation mechanism from the atomic and electronic level. The results show that boron segregation occurs mostly at Σ5(210), Σ5(310) and Σ9(114) grain boundaries, while a relatively weak segregation tendency is observed at Σ9(221), Σ3(112) and Σ11(113) grain boundaries; boron atom preferentially occupies the pentahedral or hexahedral segregation position with the largest coordination number; the interface adhesive strength at grain boundaries is improved by the segregation of boron according to the tensile test, which complies with the calculation results of Rice-Wang thermodynamic model; the chemical effect caused by the increase of local charge density after boron segregation at Σ9(114) grain boundary outstrips the adverse effect of structural changes, and the strong interaction between B-p electrons and Fe-s electrons improves the interface adhesive strength. The results provide a reference for using boron to optimize the interface structure of austenitic stainless-steel.
First-principles study of photoelectric properties of CsSnBr3 under hydrostatic pressure
Authors: Gao Li-Ke , Zhao Xian-Hao , Diao Xin-Feng , Tang Tian-Yu , Tang Yan-Lin ,   College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China,   College of Physics, Guizhou University, Guiyang 550025, China,   School of Physics and Electronic Sciences, Guizhou Normal College, Guiyang 550018, China
Published: June 2021

As an important perovskite solar cell (PSC) material, CsSnBr3 has been widely studied. Based on the density functional theory (DFT), the photoelectric properties of CsSnBr3 are studied by using the first-principles at different hydrostatic pressures. It is found that CsSnBr3 has an optimal optical band gap value of 1.34 eV under a pressure of 2.6 GPa, so only the photoelectric properties of CsSnBr3 under the hydrostatic pressure of 0 GPa and 2.6 GPa are studied, respectively. When the pressure is 2.6 GPa, CsSnBr3 has larger values of dielectric, conductivity, absorption coefficient and refractive index, the red-shifted absorption spectrum, and relatively small effective mass of electron and hole and exciton binding energy, indicating that CsSnBr3 is an efficient light absorbing material. According to the triple calculations of Born-Huang stability standard criterion, the tolerance factor T and phonon spectrum with or without virtual frequency, it is found that CsSnBr3 is stable under the pressure of 0 GPa and 2.6 GPa. According to the elastic modulus value of CsSnBr3 before and after pressure, it can be seen that the CsSnBr3 is soft, with good ductility and anisotropy. The Debye temperature and heat capacity of CsSnBr3, soon after it has been pressured, tend to be stable and are independent of temperature. The enthalpy and entropy increase with temperature increasing, and the increased amplitude is larger than those of the unpressured CsSnBr3. Gibbs free energy shows a decreasing trend, and the decrease is slightly faster when unpressured. This study shows that CsSnBr3 is a good photoelectric material after having been pressured hydrostatically, which is suitable for perovskite solar cells.
Effect of secondary electrons on SGEMP response
Authors: Zhang Han-Tian , Zhou Qian-Hong , Zhou Hai-Jing , Sun Qiang , Song Meng-Meng , Dong Ye , Yang Wei , Yao Jian-Sheng ,   Institute Applied Physics and Computational Mathematics, Beijing 100094, China
Published: June 2021

It is difficult to effectively shield the system generated electromagnetic pulse (SGEMP), which can significantly affect the performance of important electronic devices and infrastructure, such as low-orbit spacecraft. Numerical simulation is an essential way to study the SGEMP response. However, many previous studies ignored or simplified the effect of secondary electron emission in their models. In this paper, a three-dimensional electromagnetic particle-in-cell numerical simulation model is developed to evaluate the effect of secondary electrons on the SGEMP response of two typical structures (external SGEMP and cavity SGEMP, respectively) under different current densities (0.1–100 A/cm2) and different materials (Al, Cu and Au). A right cylinder or cylindrical cavity with a length of 100 mm is used. The photoelectrons produced by the interaction between the X-ray photon and metal are emitted from one end of the system and assumed to be monoenergetic. The photoelectron pulse follows a sine-squared distribution, and its full width at half maximum is 1 ns. Some important parameters of secondary electrons are discussed and summarized, including the emission coefficients of elastically and inelastically backscattered electrons, as well as the probability density functions of emission angles and energies. The results show that ignoring the secondary emission in the simulation model leads the peak electric field to be underestimated by twice-thrice, and the duration of electric field response by more than 10%. The oscillation frequency and the amplitude of the second peak of the tangential magnetic field are also increased, with the secondary electrons considered. Among various types of secondary electrons, backscattered electrons have a dominant effect on the change of SGEMP. The effect of true secondary electrons is about 1/5 of that of backscattered electrons. The effect of secondary electrons on SGEMP response increases with a higher atomic number of the material used in the system, mainly due to higher backscattering emission coefficient and a high ratio of high energy inelastically backscattered electrons. The secondary electrons will influence the response of the external SGEMP only when the space charge effect is strong (high X-ray fluence). While the response of the cavity SGEMP is more easily affected by the secondary electrons even at a relatively low X-ray fluence. This paper helps to better obtain the SGEMP response of a specific device under strong radiation through numerical simulation.
Global dynamic behavior analysis of typical magnetic pendulum
Authors: Qin Bo , Shang Hui-Lin , Jiang Hui-Min ,   School of Mechanical Engineering, Shanghai Institute of Technology, Shanghai 201418, China
Published: June 2021

Based on the analysis of the global dynamic behavior of a typical magnetic pendulum with equilateral triangular arrangement, the initial sensitivity and its mechanism are studied. To begin with, assuming that the position of the magnet can be moved, the dynamical model of a typical magnetic pendulum is established via Newton’s second law. Furthermore, the number of equilibrium points under different magnet positions and their stability are analyzed. Upon this, the initial sensitivity phenomenon and the evolution of fractal basin of attraction of point attractors under different magnet positions are presented. Finally, the initial sensitivity phenomenon is verified experimentally. It is found that the coexistence of multiple attractors generally appears in this type of magnetic pendulum. The initial sensitivity can be attributed to the fractal basin of attraction of fixed point attractors, in which the positions of the fixed point attractors do not overlap with the projected positions of the center of the magnet on the plane where the magnet is located, but there is a slight deviation. When the position of the swing ball can be projected onto the centroids of three equilateral triangles corresponding to the magnets, the sizes of the three attractors’ attraction domains will be similar, whose boundaries are fractal and centrosymmetric, thus, the initial sensitivity is obvious. It also follows that the position of moving magnet affects the nature of basin of attraction directly, i.e., the magnet which is closest to the projection point of the balance position of the swing ball has a great influence on the swing ball: the domain of attraction of the attractor whose is the closest to the position will increase significantly, while the attractor domains of the other attractors will be eroded obviously. This paper has potential applications in designing the magnetic pendulum systems.
Two-step phase shifting profilometry based on Lissajous ellipse fitting technique
Authors: Zhu Jin-Jin , Wu Yu-Xiang , Shao Xiao-Peng ,   School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071, China
Published: June 2021

 Phase shifting profilometry (PSP) is an effective technique to reconstruct the three-dimensional shape of object. In general, PSP needs three or more fringe patterns with phase-shifting accurately known to extract the phase distribution of objects. Therefore, the scene and the test objects should remain stationary during capturing the fringe patterns. However, the phase shifts may be unknown in an actual PSP measurement system, especially when measuring the moving object, that is, the phase-shift error may be introduced during the obtaining of the phase-shifting fringe patterns of moving object. In the dynamic measurement scenario, the use of fewer fringe patterns can realize the faster measurement speed and suppress the phase shift error introduced by the moving object. In this paper, a two-step PSP algorithm is proposed based on Lissajous ellipse fitting (LEF). The proposed method uses only two fringe patterns to extract the phase distribution of the object and can suppress the phase shift error caused by the moving object.

 However, in a practical PSP system, the spatiotemporally varying background intensity and modulation also significantly affect the phase accuracy extracted by LEF, and thus three error-suppressing methods are proposed to reduce the phase error caused by the non-uniform background intensity and modulation. In order to verify the effectiveness of the three error-suppressing methods, we analyze and compare their performances of error suppression under different background intensities and modulations. The advantages of three error-suppressing methods can be summarized as follows. 1) The mean and modulation correction technique has greater advantage than the other two when the background intensity and modulation vary with time. 2) When the background intensity and modulation are relevant to pixel position and the number of fringe patterns, the empirical mode decomposition normalization can more effectively suppress the influence of the non-uniform background intensity and modulation.

 In experiment, a two-step phase-shifting dynamic measurement based on LEF is conducted. Compared with the traditional PSP which needs at least three fringe patterns, the two-step PSP algorithm successfully extracts the phase with only two fringe patterns and suppresses the phase shift error caused by the motion of the object. Compared with Fourier transform profilometry (FTP), the two-step PSP algorithm can obtain very accurate phase distribution and retain many phase details.
Atomic frequency comb optical memory in EuCl3·6H2O crystal
Authors: Li Zong-Feng , Liu Duan-Cheng , Zhou Zong-Quan , Li Chuan-Feng ,   CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China,   CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
Published: June 2021

Quantum memory is a crucial component for the large-scale quantum networks. Rare-earth-ion doped crystals have been a promising candidate for the practical quantum memory because of its very long coherence time. However, doped ions cause unwanted lattice distortion, and consequently reduce the optical depth and the storage efficiency. The stoichiometric rare-earth crystals have low lattice distortion and high rare earth ion density, and thus are expected to enable high-efficiency storage. EuCl3·6H2O is a promising material for quantum memory applications because its optical inhomogeneous broadening can be smaller than its hyperfine splitting and the theoretically predicted spin coherence time is up to 1000 seconds. Despite the numerous efforts in solid-state quantum memory based on rare-earth ion doped crystals, optical memory and quantum memory have not been implemented with stoichiometric rare-earth crystals yet. Here, we report the atom frequency comb optical storage using a EuCl3·6H2O crystal. A coherence time of 55.7 μs is obtained by photon echo measurements on \begin{document}$^7{\rm{F}}_0 \rightarrow {}^5{\rm{D}}_0$\end{document} transition. The two-level atomic frequency comb storage is demonstrated with a storage efficiency of 1.71% at a storage time of 1 μs, showing the potential capability of optical quantum storage of this material. Based on the analysis of the line shift of \begin{document}$^7{\rm{F}}_0 \rightarrow {}^5{\rm{D}}_0$\end{document} depending on the sample temperature, we highlight the challenge of achieving high-efficiency optical pumping in this material, which imposes a limit on the achievable efficiency.
Temporally delayed linear modelling (TDLM) measures replay in both animals and humans
Authors: Liu Yunzhe , Dolan Raymond J , Higgins Cameron , Penagos Hector , Woolrich Mark W , Ólafsdóttir H Freyja , Barry Caswell , Kurth-Nelson Zeb , Behrens Timothy E
Published: June 2021

There are rich structures in off-task neural activity which are hypothesized to reflect fundamental computations across a broad spectrum of cognitive functions. Here, we develop an analysis toolkit – temporal delayed linear modelling (TDLM) – for analysing such activity. TDLM is a domain-general method for finding neural sequences that respect a pre-specified transition graph. It combines nonlinear classification and linear temporal modelling to test for statistical regularities in sequences of task-related reactivations. TDLM is developed on the non-invasive neuroimaging data and is designed to take care of confounds and maximize sequence detection ability. Notably, as a linear framework, TDLM can be easily extended, without loss of generality, to capture rodent replay in electrophysiology, including in continuous spaces, as well as addressing second-order inference questions, for example, its temporal and spatial varying pattern. We hope TDLM will advance a deeper understanding of neural computation and promote a richer convergence between animal and human neuroscience.
Functional biology in its natural context: A search for emergent simplicity
Authors: Bergelson Joy , Kreitman Martin , Petrov Dmitri A , Sanchez Alvaro , Tikhonov Mikhail
Published: June 2021

The immeasurable complexity at every level of biological organization creates a daunting task for understanding biological function. Here, we highlight the risks of stripping it away at the outset and discuss a possible path toward arriving at emergent simplicity of understanding while still embracing the ever-changing complexity of biotic interactions that we see in nature.
Airborne transmission pathway for coastal water pollution
Authors: Pendergraft Matthew A. , Grimes Derek J. , Giddings Sarah N. , Feddersen Falk , Beall Charlotte M. , Lee Christopher , Santander Mitchell V. , Prather Kimberly A.
Published: June 2021

Each year, over one hundred million people become ill and tens of thousands die from exposure to viruses and bacteria from sewage transported to the ocean by rivers, estuaries, stormwater, and other coastal discharges. Water activities and seafood consumption have been emphasized as the major exposure pathways to coastal water pollution. In contrast, relatively little is known about the potential for airborne exposure to pollutants and pathogens from contaminated seawater. The Cross Surfzone/Inner-shelf Dye Exchange (CSIDE) study was a large-scale experiment designed to investigate the transport pathways of water pollution along the coast by releasing dye into the surfzone in Imperial Beach, CA. Additionally, we leveraged this ocean-focused study to investigate potential airborne transmission of coastal water pollution by collecting complementary air samples along the coast and inland. Aerial measurements tracked sea surface dye concentrations along 5+ km of coast at 2 m × 2 m resolution. Dye was detected in the air over land for the first 2 days during two of the three dye releases, as far as 668 m inland and 720 m downwind of the ocean. These coordinated water/air measurements, comparing dye concentrations in the air and upwind source waters, provide insights into the factors that lead to the water-to-air transfer of pollutants. These findings show that coastal water pollution can reach people through an airborne pathway and this needs to be taken into account when assessing the full impact of coastal ocean pollution on public health. This study sets the stage for further studies to determine the details and importance of airborne exposure to sewage-based pathogens and toxins in order to fully assess the impact of coastal pollution on public health.
Screening of Biochemical Abnormalities in Suicide Attempters Irrespective of Psychiatric Diagnosis: A Cross-sectional Study
Authors: Kamble Ashwini , Vatte Vishwak Reddy , Rao Bheemathati Ranga , Reddy Sourya , Pradyumna C , Satyanarayana PV Sai , Karri Satya Revanth , Khairkar Praveen
Published: June 2021

Introduction: Empirical studies have documented the impact of membrane cholesterol on serotonergic function which might influence the suicidality in various psychiatric disorders. Most studies in last two decades demonstrated low cholesterol as potential predictor of suicidality in depression but trends of metabolic disorders and current status of hypercholesterolemia and biochemical abnormalities in suicidal spectrum population is scarce. Aim: The present study was aimed to comprehensively evaluate the blood levels of cholesterol and other biochemical abnormalities (serum electrolytes, proteins, blood pH etc.,) irrespective of any psychiatric disorders in suicide attempters. Materials and Methods: A cross-sectional study was conducted on a total of 202 patients who visited our emergency hospital services with the suicidal attempt from 1st January 2019 till 31st December 2019 for a period of 12 Months. Blood evaluation and analysis were done on the same day of hospitalisation for complete blood counts, serum electrolytes, proteins and cholesterol levels. Clinical and standardised psychological evaluations for psychiatric diagnosis were performed. The results were analysed and compared using descriptive and inferential statistics based on SPSS software 21.01. Results: Out of 202 total suicide attempters, 120 (59.4%) were males and 82 (40.6%) were females with most patients 111 (54.9%) falling in the age range of 20-29; while 175 (86.6%) of patients had their first ever suicide or deliberate harm. A total of 169 (83.7%) of patients had normal complete blood counts but 106 (52.5%) showed acidic pH (<7.3) while only 5 (2.5%) of the patients had alkalosis. Serum potassium was abnormal in 43 (21.3%) patients. Further serum chloride was deranged in 13(6.4%) while serum albumin was deranged in 17 (8.4%). About 27 (13.4%) found to have increased serum cholesterol and none of them had low cholesterol. Conclusion: Excessive and dampened reactivity of biomolecular parameters including hypercholesterolemia may modulate the neurobiological stress system associated with increased suicidality. This may be one of the predictors irrespective of the underlying psychiatric disorders.
Student Perception Regarding the Utility of Information Technology as a Facilitator of Learning in Medical Education
Authors: Khurana Vatsala , Verma Rashmi , Goswami Binita , Malhotra Vikas
Published: June 2021

Introduction: Information Technology (IT) has influenced all fields including healthcare and Medical Education (ME). The present generation of students have grown up in an IT enriched atmosphere and are comfortable with most IT tools and gadgets. Aim: To understand the perception of first year MBBS students regarding role of IT in ME. Materials and Methods: A cross-sectional, questionnaire based study was carried out on 250 first year MBBS students from August 1st, 2019 to August 31st, 2019 over a period of one month. A questionnaire containing three sections was administered to the students before the starting of IT module in foundation year. The responses to the items of the questionnaire were assessed on the basis of the student responses on the likert scale. Results: The study revealed that students acknowledged the utility of IT for academic purposes and were primed for its inclusion as an essential component of the medical curriculum. The students conceded to browsing internet on their computers and smartphones for social media handles. However, when it came to teaching methods, students were not comfortable with the idea of replacing traditional teaching methods with e-learning. Also, students were more comfortable in reading hard copies instead of e-books. Conclusion: It was concluded that there is a need to amalgamate the traditional teaching methods with the innovative e-learning platforms in such a way that they become mutually inclusive and facilitate the learning process. Also, ME practices need to be continuously re-evaluated to make the educational process more effective for learners, teachers and for the society in general.
A Rare Case of Diffuse Intestinal Ganglioneuromatosis in a Child Presenting with Intussusception
Authors: Sekaran Anuradha , Patil Amruta , Shetty Mahesh , Rao Guduru Venkat , Reddy Duvvur Nageshwar
Published: June 2021

Ganglioneuromas are benign neurogenic neoplasms commonly seen in children which are originating from neural crest cells of sympathetic ganglia or adrenal medulla. Rarely, they may arise from the visceral organs like intestine. Diffuse intestinal ganglioneuromatosis is a rare disease, caused due to abnormal proliferation of ganglion cells, nerve fibres and schwann cells in the wall of intestine. Author hereby present a case of diffuse intestinal ganglioneuromatosis in an 18-month-old male child who presented with symptoms of small bowel obstruction. Resected segment of ileocecal junction revealed ulcero-nodular areas which on microscopy showed diffuse hyperplasia of nerve bundles and ganglion cells with immunohistochemistry confirmation. Intestinal ganglioneuromatosis is a rare condition having syndromic association with MEN-2B, Neurofibromatosis-1 and Cowden syndrome. As this disease has a low clinical suspicion, very nonspecific symptoms and radiological findings, histopathological examination becomes mainstay in diagnosis. Further workup is essential to rule out presence of associated syndromes.Surgical excision is the ultimate treatment with screening for genetic abnormalities.
Characterisation and Antibiotic Susceptibility Pattern of Enterococci in a Tertiary Care Hospital of North East India
Authors: Roy Antara , Singh Rajkumar Manojkumar , Laifangbam Supriya
Published: June 2021

Introduction: Enterococci are important agents of nosocomial infection, ranking as the second most common organisms causing complicated urinary tract infections, bacteraemia, endocarditis, intra-abdominal and pelvic infections, wound and soft tissue infections, neonatal sepsis, and, rarely, meningitis. Infections by enterococci have traditionally been treated with cell wall active agents (e.g., penicillin or ampicillin) in combination with an aminoglycoside (streptomycin/gentamicin); however, emergence of High Level Aminoglycoside Resistance (HLAR), β lactam antibiotics resistance and vancomycin resistance by some strains has led to failure of synergistic effects of combination therapy. Aim: To characterise enterococci up to the species level and study their antibiotic susceptibility pattern. Materials and Methods: The present study was a cross-sectional study in which a total of 14114 clinical specimens, obtained during the period from September 2018 to August 2020 in this cross-sectional study, were tested to identify and speciate enterococcal isolates using standard microbiological methodology. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method. Data was analysed using descriptive statistics (percentage and proportion). Results: During the study period of two years, 146 enterococci were recovered from 14114 different clinical samples, accounting for an infection rate of 1.03%. Among 146 enterococcal isolates, 116 (79.5%) were obtained from urine, 13 (8.9%) from blood, 10 (6.8%) from pus, 4 (2.7%) from wound swab and 3 (2.1%) from catheter tip. The predominant isolates were E. faecalis (82.2%) followed by E. faecium (15.8%), E.durans (1.3%) and E.gallinarum (0.7%). On studying the antibiotic susceptibility pattern, most of enterococcal isolates were predominantly resistant to ampicillin and ciprofloxacin (73.9% in both) and least resistant to linezolid (3.4%). Conclusion: Enterococcus faecalis and Enterococcus faecium were the predominant species in present study and majority of the isolates was sensitive to linezolid (96.6%). Therefore, it is necessary to implement infection control measures like antimicrobial stewardship especially restricting the use of antibiotics to minimum.
Utility of Nucleic Acid Extraction Free COVID-19 Real Time PCR Protocol in Resource Limited Setting: A Pilot Study
Authors: Karade Santosh , Thosani Pratik , Patil Prashant , Anand Kavita Bala , Sen Sourav , Gupta Rajiv Mohan
Published: June 2021

Introduction: Coronavirus Disease (COVID-19), a respiratory infection, caused by severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, Hubei province, China in December 2019. Alarming increase in the number of cases has put tremendous pressure on existing health resources. Real Time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR), a molecular diagnostic method, is considered gold standard for diagnosis of SARS-CoV-2 infection. It involves RNA extraction as the preliminary step. Innovations to cut down cost and time involved in SARS-CoV-2 testing are need of hour. Aim: The aim of this study was to assess the feasibility of Nucleic Acid Extraction Free (NEF) protocol for COVID-19 diagnosis in resource limited settings. Materials and Methods: In this pilot study a panel of 148 Nasopharyngeal (NP) samples was subjected to the novel NEF RT-PCR protocol and results were compared to gold standard RT-PCR on RNA extracted from NP specimen. The cycle threshold value for each target was tabulated in MS Excel Spreadsheet and data analysis was performed using Statistical Package for Social Sciences (SPSS) software version 15.0. Results: Out of 148 collected samples, 120 showed amplification of E and RdRp targets by RNA extraction-based RT-PCR. Overall sensitivity and specificity observed for NEF protocol was 43.94% and 96.42%, respectively. Conclusion: Further refinement in the protocol would be required to improve the sensitivity of NEF protocol and widespread use in laboratories.
Protocol for a Systematic Review of School Based Educational Interventions on Prevention and Control of Malaria
Authors: Roja Chokkara , Lakshmi A Seetha , Rani M Anitha , Eapen Alex
Published: June 2021

Introduction: Schools are an integral part of the community and creating health awareness at the educational premises is one of the successful policies for the health promotion. School children play an active role as health changing agents in the community and hence, can be the health messengers for malaria prevention. The need of the current review is to strengthen the evidences towards malaria elimination. Aim: To evaluate the influence of school based educational interventions for the malaria control and prevention activities. Materials and Methods: This review on malaria will search the literature from databases such as PubMed, Medline, CINAHL Plus, Cochrane Library, Google Scholar and Science Direct using keywords. It will follow Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Quantitative studies (Randomised trials and Non randomised trials) published from 2001 to 2020 in English language will be included. Joanna Briggs Institute (JBI) critical appraisal checklist will be used to assess the quality of the studies. Findings of the selected articles will be presented in the form of narrative summaries along with statistical interpretations. Conclusion: This review on school based educational interventions will provide evidences in order to take preventive and control measures on malaria. It will support the hypothesis that school based educational interventions play an essential role to enhance knowledge about malaria, reduce malaria prevalence and promote preventive measures in the community.
Association of Demographic, Clinical and Laboratory Parameters with Clinical Outcome of COVID-19 Patients of Bangalore: A Cross-sectional Study
Authors: Krishnegwda Ravi , Rajanna Avinash Hanbe , Shetty B Abhiman , Desai Rakshit R , Gurumurthy Thejaswik , Navalba Kiran Kumar , Shenoy Vallish , Bhat Bhargav V
Published: June 2021

Introduction: Although the Coronavirus Disease-2019 (COVID-19) pandemic is creating a major global health crisis, the risk factors for mortality and the detailed clinical course of disease has not yet established. Aim: To determine association of the demographic data of COVID-19 patients with clinical profile and disease outcomes. Materials and Methods: The cross-sectional single-center study considered adults patients of both the gender from March to June 2020 with an estimated sample size of 2000 patients diagnosed with COVID-19 infection by Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) technique. Necessary demographic and clinical data were collected and selected subjects were followed-up until discharge or death. Subjects were classified as those who survived (1839 patients) and succumbed (138 patients) to death. T-test was used for comparing continuous variables and chi-square test for categorical data between the groups. Results: The study included 1977 patients with a male-to-female ratio of 1:0.62. Fever, dyspnea and cough were noted as the major symptoms prevalent among patients who succumbed to death when compared to those who survived (p-value <0.001). Statistically significant variables noted between the groups were age (survived mean age- 42.74±15.15 years vs mean age 59.12±12.95 in those who succumbed to death, p-value <0.001), age groups (p-value <0.001), gender (p-value 0.042), haemoglobin, Total Leucocyte Count (TLC), neutrophil, lymphocytes, Neutrophil to Lymphocyte Ratio (NLR), Lactate Dehydrogenase (LDH), ferritin, all the comorbidity variables and the asymptomatic status. Variables identified as significant predictors of disease outcomes were Haemoglobin (Hb), TLC, neutrophils, lymphocytes, NLR, LDH and ferritin (p-value <0.001). Most of the subjects belonging to the mortality group required oxygen and other Intensive Care Unit (ICU) facilities when compared to the survival group (p-value <0.001). The mean days of viral clearance noted in COVID subjects was around 8.98±3.54 days. Conclusion: Hb, TLC, neutrophils, lymphocytes, NLR, LDH and ferritin are noted as significant predictors of COVID-19 outcome. Biochemical monitoring of COVID-19 patients helps in identifying critically ill patients early and can reduce mortality and improve the recovery.
Inherent Microorganisms Affects the Quality of a Nigerian Fermented Beverage “Agadagidi” During Production
Authors: Mogaji K. J. , Arotupin D. J. , Mogaji O. , Arogunjo A. O. , AJayi-Moses O. B. , Akinwunmi I. M. , Gabriel P. O. , Orekoya E. S. , Olajesu O. L. , Adeleye H. J. , Aribisala J. O.
Published: June 2021

This research produced wine from unripe plantain fruits using spontaneous fermentation method. The period of production was five days. The purpose of this study was to isolate and identify microorganisms associated with unripe plantain fruits, determine the physicochemical parameters of the fermenting medium. Microbial count, foaming density, alcohol content, enzymes assay, sensory analysis, physicochemical properties, mineral content, antioxidants properties, and antinutrient content of the sample were investigated every 24 h for 5 days. A total of seven bacteria and four fungi consisting of yeasts and moulds were isolated during the study. The microbial loads of bacteria and fungi of the unfermented plantain fruits were 8.0 × 106 ± 0.01 cfu/mL and 14.2 × 104 ± 0.01 sfu/mL respectively. The temperature (ºC), pH and titratable acidity (%) ranged from 25.55-32.50, 4.51-5.50 and 0.99-3.50 respectively. The sample was observed to be colourless all through the fermentation periods. Turbidity of the samples increased during fermentation from 43.50 to 111.00. The data obtained from this work has shown the importance of unripe plantain micro-flora in the production of “Agadagidi”. It is also concluded that consortium of microorganisms inherent within the plantain fruits are involved in plantain fruits fermentation. This information can contribute to a better understanding of the “Agadagidi” production process for a consistent quality beverage.
Non-negative Integer Power of a Hyponormal m-isometry is Reﬂexive
Authors: Kothiyal Pradeep , Pal Rajesh Kumar , Nigam Deependra
Published: June 2021

Sarason did pioneer work on reflexive operator and reflexivity of normal operators, however, he did not used the word reflexive but his results are equivalent to say that every normal operator is reflexive. The word reflexive was suggested by HALMOS and first appeared in H. Rajdavi and P. Rosenthals book `Invariant Subspaces’ in 1973. This line of research was continued by Deddens who showed that every isometry in B(H) is reflexive. R. Wogen has proved that `every quasi-normal operator is reflexive’. These results of Deddens, Sarason, Wogen are particular cases of theorem of Olin and Thomson which says that all sub-normal operators are reflexive. In other direction, Deddens and Fillmore characterized these operators acting on a finite dimensional space are reflexive. J. B. Conway and Dudziak generalized the result of reflexivity of normal, quasi-normal, sub-normal operators by proving the reflexivity of Vonneumann operators. In this paper we shall discuss the condition under which m-isometries operators turned to be reflexive.
Multiple Intramedullary Nailing Versus Low Profile Mini-Plating in Unstable Metacarpal Neck Fractures
Authors: Aboelnaga Amr A. , Ramadan Mohammed Osama , Quolquela Muhammad Abdel-Monem , Hegazy Mostafa Hussein
Published: June 2021

Background: Neck fractures of the metacarpal bone can alter optimal hand function. Many surgical fixation techniques are described for this fracture with no robust evidence for the best treatment. Recently developed low profile plates may, however, challenge the preference for K-wires. Low profile plates were found to have lower complications than conventional plates in addition to early range of motion and early return to work. The aim of the present study was to determine the best outcome in patients with unstable fracture neck metacarpals using either multiple K wires or low profile mini-plating.

Methods: This prospective randomized controlled study included 37 patients suffering from metacarpal neck fractures. patients were designated as group 1 (AIN group; 18 patients), and the other consecutive patients were designated as group 2 (LPP group; 19 patients). Both groups were treated within the first 48 hours of their injury and followed up for a minimum period of 40 weeks; the maximum period of follow up was 48 weeks.

Results: No significant differences were found for PVAS, Q-DASH, TAM, time to radiological union or residual deformities at last follow-up. Grip strength, however, was significantly better in the K-wire group. Operative time and time off work were significantly shorter in the k-wire group. Plate group showed prevalent complications both peri and post-operative hitting 63.2 % of the plate group vs 16.7% in K-wire group.

Conclusions: Low profile plates with immediate mobilization paradoxically prolonged operative time, technical demand and disturbing the fracture’s biological environment along with the extra cost were thus not justified by results. Antegrade intramedullary K-wire nailing was superior for the management of unstable metacarpal neck fractures.
Determining the Dynamic Contrast - Enhanced Magnetic Resonance Imaging (DCE- MRI) in Diagnosis of Pulmonary Nodules
Authors: El-Nenaey Mona Adel , Alashwah Mohamed Mahmoud , Al-Shafey Basem Ibrahim , El-Badry Amr Mohamed
Published: June 2021

Objective: The aim of this study is to evaluate the role of dynamic contrast _ enhanced magnetic resonance imaging (DCE-MRI) in diagnosis of pulmonary nodules.

Patients and methods: The study was a cross-sectional study that was conducted on 30 patients with lung nodules referred to Radio diagnosis and imaging department from chest and oncology departments. By performing repeated CT within 30 days, we identified malignant nodules. The CT was repeated at 3 and 6 months which showed that the malignant pulmonary nodules increased in size and number.

Results: The maximum enhancement curve was a significant discriminator. At cut-off value of ≥ 375, the maximum enhancement curve yielded a sensitivity of 92.6% and specificity of 96% (figure 3). In contrary, the ADC value had poor diagnostic accuracy in differentiating between malignant and benign cases.

Conclusion: Dynamic contrast-enhanced MRI is valuable for diagnosis of pulmonary nodules and discrimination of benign from malignant ones.
A comparative Clinical Study to Evaluate the Efficacy of Anuvasan Basti with Brahatchaglyadi Ghritam and Guggulutiktam Ghritam in the management of Gridhrasi (Sciatica): A Study Protocol
Authors: Gupta Arun Kumar , Parwe Shweta , Gupta Trupti , Nisargandha Milind
Published: June 2021

Background: Gridhrasi is such a Ruja Pradhaana Vatavyadhi. In Gridhrasi intense shooting pain characteristically radiates from Sphika (gluteal region) to Pada (foot). Based on symptoms of Gridhrasi, it can be equated with the disease sciatica in modern science. The lifetime incidence of low back pain is 50-70%, with Sciatica more than 40%. Charaka has considered Basti therapy as half of the disease's treatment, while some authors consider it as the complete remedy for all the ailments. Basti is one of the unique procedures explained for the management of Vatavyadhi (Neurological Disorder) where Gridhrasi (Sciatica) is being the predominant of Vata dosha, Basti is being used widely for the management of Gridhrasi (Sciatica). Therefore we have taken the Basti modality for the treatment of Gridhrasi (Sciatica). Hence the study is carried to evaluate the effect of Anuvasanbasti with Brihachagalyadi Ghritam & Guggulutiktaka Ghritam in the management of Gridhrasi (Sciatica).

Aims and Objectives: Evaluate Anuvasan Basti's efficacy with Brihatchagalyadi Ghritam & Guggulutiktaka Ghritamin the control of Gridhrasi (Sciatica) and to compare the effectiveness of Brihachagalyad Ghritam & Guggulutiktak Ghritam Anuvasan Basti in the direction of Gridhrasi. Methodology: Procedure: This study, a total of 66 patients, will be separated haphazardly divided into 2 groups (33 in each). In Group A (Interventional Group)- will Treat with Brihachagalyadi Ghritam as an Anuvasan Basti in increasing dose pattern for nine days and Group B (Control Group ) –patients will Treat with Guggulutiktaka Ghritam as an Anuvasanbasti in increasing dose pattern for nine days. The evaluation will be recorded on 0 and 9thday.

Conclusion: It may be more beneficial and more effective in pain as well as other subjective and objective parameters.
Androgenetic Alopecia as a Marker of Metabolic Syndrome
Authors: Memon Faryal Hussain , Rahimoon Abdul Ghani , Kumar Pardeep , Memon Shahid Hussain , Siddiqui Erum , Devrajani Tarachand , Raza Samar , Shah Syed Zulfiquar Ali
Published: June 2021

Background: Alopecia induced by androgens in genetically predisposed individuals is termed as Androgenetic alopecia (AGA). There is proof appearance the relationship between Androgenetic alopecia and metabolic condition.

Objective: To determine frequency of metabolic syndrome in Androgenetic alopecia as a biomarker of disease in adult male patients.

Materials and methods: It was a Cross Sectional Study conducted at the Department of Dermatology, Liaquat University of Medical and Health Sciences Hospital, Jamshoro/Hyderabad.

Total 178 diagnosed male patients of Androgenetic alopecia were included. The grading of male pattern Androgenetic alopecia was done according to modified Norwood-Hamilton classification. Norwood-Hamilton Stage I-III were regarded to be mild to moderate and Stage IV and higher were regarded as severe. Vein was engorged by a tourniquet applied above the cubital fossa. Blood glucose levels were estimated. The level of triglycerides was determined. HDL-Cholesterol was estimated by a pre­cipitant method. Descriptive statistics were calculated using SPSS. Chi square tests were applied to determine the relationship of independent variables with metabolic syndrome.

Results: The overall mean age of the patients was 39.08±10.14 years. The mean waist circumference, triglycerides, high-density lipoprotein cholesterol, systolic blood pressure, diastolic blood pressure and fasting blood glucose were 94.71±12.30 cm, 133.83±13.27 mg/dl, 48.10±7.89 mg/dl,102.94±17.67 mmHg, 76.88±8.56 mmHg, and 93.06±9.78 mg/dl respectively. A total of 10.1% of the patients were found to have metabolic syndrome. There was a significant association between metabolic syndrome and age and family income.

Conclusion: Metabolic syndrome was observed in 10.1% of the patients and this was more commonly found in: the age group >40 years, married individuals, low socioeconomic status individuals, and illiterate individuals.
Development and Validation of Direct Spectrophotometric Method for the Estimation of Glimepiride
Authors: Chafle Dilip , Awale Lata
Published: June 2021

Aims: To develop simple, sensitive and direct spectrophotometric methods for the estimation of widely prescribed antidiabetic hypoglycemic agent Glimepiride in pure and pharmaceutical dosage form.

Place and duration of study: Research Centre of Taywade Group of Institution Koradi, Nagpur affiliated to Rashtrasant Tukadoji Maharaj Nagpur University Nagpur between June 2020 and March 2021.

Methodology: Two spectrophotometric methods were developed based on ion-pair formation of drug with Cresol Red dye (Method A) and Bromophenol Blue dye (Method B) in methanol and chloroform. The possible reaction mechanism was proposed with evaluation of statistical parameters. The methods were validated for its application to determine Glimepiride in bulk as well as in pharmaceutical formulations

Results: The Beer's law was found linear in the range 10 - 60 µgml-1 at 450 nm for method A and 2 - 20 µgml-1 at 578 nm for method B, respectively. The linear regression equation obtained by applying least square regression analysis for Glimepiride were found to be Absorbance = 0.0136 x Concentration in µgml-1 + 0.028; R2 = 0.9965 for method A and Absorbance = 0.0428x Concentration in µgml-1 +0.0722; R2 = 0.9949 for method B. The Sandell's sensitivity was found to be 0.0696 and 0.0177 for method A and B respectively. The apparent molar absorptivity calculated to be for both methods were 6.6724 x103 and 2.0999 x104 l mol-1 cm-1.

Conclusion: Two direct spectrophotometric methods for determination of Glimepiride have been developed successfully and validated for sensitivity, accuracy, precision, repeatability and robustness as per ICH guidelines. The developed methods are suitable for the routine estimation of Glimepiride in pure and dosage form.