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Transformations of the Pleiomorphic Plant MTOc during Sporogenesis in the Hepatic Marchantia polymorpha

Journal of Integrative Plant Biology 2007年第8期49卷 1244-1252页

作者： roy c.brown Betty E.Lemmon Masaki Shimamura Department of Biology University of Louisiana-LafayetteLafayetteLA 70504USA Department of Biological ScienceGraduate School of ScienceHiroshima UniversityKagami-yamaHigashi-Hiroshima 739-8526Japan

Sporogenesis in the hepatic Marchantia polymorpha L. provides an outstanding example of the pleiomorphic nature of the plant microtubule organizing center （MTOc）. Microtubules are nucleated from γ-tubuUn in MTOcs that change form during mitosis and meiosis. Following entry of cells into the reproductive pathway of sporogenesis, successive rounds of mitosis give rise to packets of 4-16 sporocytes. Mitotic spindles are organized at discrete polar organizers （POs）, a type of MTOc that is unique to this group of early divergent land plants. An abrupt and radical transformation in microtubule organization occurs when sporocytes enter meiosis： POs are lost and γ-tubulin is closely associated with surfaces of two large elongated plastids that subsequently divide into four. Migration of the four plastid MTOcs into a tetrahedral arrangement establishes the future spore domains and the division polarity of meiosis. As is typical of many bryophytes, cones of microtubules from the four plastid MTOcs initiate a quadripolar microtubule system （QMS） in meiotic prophase. At this point a transformation in the organization of the MTOcs occurs. The γ-tubulin detaches from plastids and forms a diffuse spheroidal pole in each of the spore domains. The plastids, which are no longer MTOcs, continue to divide. The diffuse MTOcs continue to nucleate cones of microtubules during transformation of the QMS to a bipolar spindle. Following meiosis I, γ-tubulin is associated with nuclear envelopes, and the spindles of meiosis II are organized from diffuse MTOcs at the tetrad poles. At simultaneous cytokinesis, radial microtubule systems are organized at nuclear envelope MTOcs in each of the tetrad members.

关键词： bryophyte γ-tubulin meiosis microtubules mitosis MTOc.

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Practice patterns among ophthalmic surgeons in treating concomitant oculoplastic conditions in preoperative period:A questionnaire-based study

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World Journal of clinical cases 2025年第1期13卷 29-37页

作者： Bijnya Birajita Panda chitaranjan Mishra Bhagabat Nayak Avik Kumar roy Logesh Balakrishnan Priyadarshini Mishra Department of Ophthalmology All India Institute of Medical SciencesBhubaneswar 751019OdishaIndia Department of Vitreo-Retina Trilochan NetralayaSambalpur 768004India Department of Glaucoma Services LV Prasad Eye InstituteBhubaneswar 751013India Department of Statistics Apollo HospitalsChennai 823104India

BAcKGROUND Addressing oculoplastic conditions in the preoperative period ensures both the safety and functional success of any ophthalmic *** oculoplastic conditions,like nasolacrimal duct obstruction,have been extensively studied,whereas others,like eyelid malposition and thyroid eye disease,have received minimal or no *** To investigate the current practice patterns among ophthalmologists while treating concomitant oculoplastic conditions before any subspecialty ophthalmic *** A cross-sectional survey was disseminated among ophthalmologists all over *** survey included questions related to pre-operative evaluation,anaesthetic and surgical techniques preferred,post-operative care,the use of adjunctive therapies,and patient follow-up *** A total of 180 ophthalmologists responded to the *** practitioners(89%)felt that the ROPLAS test was sufficient during pre-operative evaluation before any subspecialty surgery was *** most common surgical techniques employed were lacrimal drainage procedures(Dacryocystorhinostomy)(63.3%),eyelid malposition repair(36.9%),and ptosis repair(58.7%).Post-operatively,47.7%of respondents emphasized that at least a 4-week gap should be maintained after lacrimal drainage procedures and eyelid ***-seven percent of ophthalmologists felt that topical anaesthetic procedures should be preferred while performing ocular surgeries in thyroid eye disease *** Approximately 50%of ophthalmologists handle prevalent oculoplastic issues themselves,seeking the expertise of an oculoplastic surgeon under particular *** ophthalmologists still favor using ROPLAS as a preliminary screening method before proceeding with cataract *** conditions and thyroid eye disease are not as commonly addressed before subspecialty procedures compared to issues like nasolacrimal duct obstruction and periocular infections.

关键词： Oculoplasty Ophthalmic plastic surgery Nasolacrimal duct obstruction Practice patterns Survey

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Effect of sintering temperature on the chemical bonding,electronic structure and electrical transport properties of β-Ga_(1.9)Fe_(0.1)O_(3) compounds

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Journal of Materials Science & Technology 2021年第8期67卷 135-144页

作者： Swadipta roy c.V.Ramana center for Advanced Materials Research(cMR) University of Texas at El PasoEl Paso500 W University AveEl PasoTX79968United States

A model system,which is based on iron(Fe)doped gallium oxide(Ga_(2)O_(3))(Ga_(1.9)Fe_(0.1)O_(3)),has been considered to elucidate the combined effect of transition-metal ion doping and processing temperature on the chemistry,local structure and chemical bonding,and electrical transport properties of a wide band gap oxide(Ga_(2)O_(3)).The Ga_(1.9)Fe_(0.1)O_(3) compounds were synthesized using standard high-temperature solid state reaction *** effect of processing conditions in terms of different calcination and sintering environments on the structural and electrical properties of Ga_(1.9)Fe_(0.1)O_(3) compounds is studied in *** characterization by Raman spectroscopy revealed that Ga_(1.9)Fe_(0.1)O_(3) compounds exhibit monoclinic crystal symmetry,which is quite similar to the intrinsic parental crystal structure,though Fedoping induces lattice *** temperature(T_(sint))which was varied in the range of 900-1200℃,has significant impact on the structure,chemical bonding,and electrical properties of Ga_(1.9)Fe_(0.1)O_(3) *** spectroscopic measurements indicate the proper densification of the Ga_(1.9)Fe_(0.1)O_(3) compounds achieved through complete Fe diffusion into the parent Ga_(2)O_(3) lattice which is evident at the highest sintering *** X-ray photoelectron spectroscopy validates the chemical states of the constituent elements in Ga_(1.9)Fe_(0.1)O_(3) *** electrical properties of Ga_(1.9)Fe_(0.1)O_(3) fully controlled by T_(sint),which governed the grain size and microstructural *** temperature and frequency dependent electrical measurements demonstrated the salient features of the Fe doped Ga_(2)O_(3) *** activation energy determined from Arrhenius equation is 0.5 e *** results demonstrate that control over structure,morphology,chemistry and electrical properties of the Ga_(1.9)Fe_(0.1)O_(3) compounds can be achieved by optimizing T_(sint).

关键词： Ga_(2)O_(3)compounds Fe-doping Raman spectroscopy chemical bonding Electrical properties

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OH and O radicals production in atmospheric pressure air/Ar/H_2O gliding arc discharge plasma jet

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Plasma Science and Technology 2017年第12期19卷 71-80页

作者： N c roy M R TALUKDER A N cHOWDHURY Plasma Science and Technology Laboratory Department of Applied Physics and Electronic EngineeringUniversity of RajshahiRajshahi 6205Bangladesh Bangladesh council of Scientific and Industrial Research Laboratory Rajshahi Rajshahi 6206Bangladesh

Atmospheric pressure air/Ar/H_2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic（OES） diagnostic technique is used for the characterization of plasmas and for identifications of OH and O radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx？≈？5550–9000 K, rotational Tr？≈？1350–2700 K and gas Tg？≈？850–1600 K temperatures, and electron density n？（1.1-1.9） ′101 4 cm^（-3） e under different experimental conditions. The production and destruction of OH and O radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of OH and O radicals indicate that their production rates are increased with increasing Ar content in the gas mixture and applied voltage. nereveals that the higher densities of OH and O radicals are produced in the discharge due to more effective electron impact dissociation of H_2O and O_2 molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced n *** productions of OH and O are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, Tgsignificantly reduces with the enhanced air flow rate. This investigation reveals that Ar plays a significant role in the production of OH and O radicals.

关键词： reactive oxygen species(ROS) optical emission spectroscopy(OES) gliding arc discharge plasma kinetics broadening mechanism

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AstroSat Observations of the Be/X-Ray Binary XTE J1946+274 During 2018 and 2021 Outbursts

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Research in Astronomy and Astrophysics 2023年第4期23卷 26-43页

作者： Amar Deo chandra Jayashree roy P.c.Agrawal Indian Institute of Science Education and Research Kolkata Mohanpur 741246West BengalIndia Inter-University center for Astronomy and Astrophysics Post Bag 4Pune 411007MaharashtraIndia Department of Astronomy and Astrophysics Tata Institute of Fundamental ResearchHomi Bhabha RoadMumbai 400005MaharashtraIndia

We present the timing and spectral studies of the Be/X-ray binary XTE J1946+274 during its 2018 and 2021 giant outbursts using observations with the SXT and LAXPc instruments on the AstroSat *** the 1998 and 2010 outbursts,where a giant outburst was followed by several low intensity periodic outbursts,the 2018 and 2021 outbursts were single *** X-ray pulsations are detected over a broad energy band covering 0.5–80 keV from the compact *** construct the spin evolution history of the pulsar over two decades and find that the pulsar spins-up during the outbursts but switches to spin-down state in the quiescent periods between the *** resolved pulse profiles generated in several bands in 0.5–80 keV show that the pulse shape varies with the *** energy spectrum of the pulsar is determined for the 2018 and 2021 *** best fit spectral models require presence of cyclotron resonant scattering feature at about 43 keV in the energy spectra of both the *** find indication of possible reversal in the correlation between the cyclotron line energy and luminosity which needs to be ascertained from future *** the best fit spectra the X-ray luminosity of XTE J1946+274 is inferred to be 2.7×10^(37) erg s^(-1) for the 2018 observations and 2.3×10^(37) erg s^(-1) for the 2021 *** discuss possible mechanisms which can drive outbursts in this transient Be X-ray binary.

关键词： accretion-accretion disks-stars neutron-(stars:)pulsars general-X-rays binaries-stars emission-line-Be-X-rays bursts

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Quantized Redshift and its Significance for Recent Observation

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Research in Astronomy and Astrophysics 2024年第9期24卷 156-166页

作者： Arindam Mal Sarbani Palit christopher c.Fulton Sisir roy Indian Space Research Organization Space Applications CentreAhmedabadIndia Indian Statistical Institute CVPR UnitKolkataIndia Protostar Inc.15652 Carrousel DriveCanyon CountryCA 91387USA National Institute of Advanced Studies IISC CampusBangaloreIndia

With the recent observational evidence in extragalactic astronomy,the interpretation of the nature of quasar redshift continues to be a research *** high redshifts are being detected for extragalactic objects that are presumably very distant and young while also exhibiting properties that are characteristic of a more mature galaxy such as *** to Halton Arp and Geoffrey Burbidge,redshift disparities consist of an intrinsic component and are related to an evolutionary *** observed redshift periodicity at integer multiples of0.089 in log scale and Burbidge observed redshift periodicity at integer multiples of 0.061 in linear *** Singular Value Decomposition based periodicity estimation is known to be superior for noisy data sets,especially when the data contain multiple harmonics and overtones,mainly irregular in nature,we have chosen it to be our primary tool for analysis of the quasar-galaxy pair redshift *** have observed a fundamental periodicity of0.051 with a confidence interval of 95%in linear scale with the site-available Sloan Digital Sky Survey Data Release 7(SDSS DR7)quasar-galaxy pair data *** have independently generated quasar-galaxy pair data sets from both 2d F and SDSS and found fundamental periodicities of 0.077 and 0.089,respectively,in log scale with a confidence interval of 95%.

关键词： galaxies:distances and redshifts (galaxies:)quasars:absorption lines cosmology:observations

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AstroSat observation of the Be/X-ray binary Pulsar 3A 0726–260(4U 0728–25)

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Research in Astronomy and Astrophysics 2020年第9期20卷 349-357页

作者： Jayashree roy Prahlad c.Agrawal Baibhav Singari Ranjeev Misra UM-DAE centre for Excellence in Basic Sciences University of MumbaiVidyanagari CampusMumbai400098MaharashtraIndia Inter-University center for Astronomy and Astrophysics Post Bag 4Pune411007MaharashtraIndia School of Physical Sciences National Institute of Science Education and Research BhubaneswarKhurda752050OdishaIndia

Results on timing and spectral properties of the Be/X-ray binary pulsar 3A 0726-260(4U 0728-25)are *** binary was observed on 2016 May 6-7 with the Large Area X-ray Proportional counter(LAXPc)and Soft X-ray Telescope(SXT)instruments onboard the AstroSat *** this observation,the source was in non-flaring persistent state at a flux level of^8.6±0.3×10^-11 erg cm^-2 s^-1in 0.4-20 *** X-ray pulsations with a period of 103.144±0.001 s are detected in 0.3-7 keV with the SXT and in 3-40 keV with the *** pulse profile is energy dependent,and there is an indication that the pulse shape changes from a broad single pulse to a double pulse at higher *** energies above20 keV,we report the first time detection of pulsation period 103.145±0.001 s and the double peaked pulse profile from the *** energy spectrum of the source is derived from the combined analysis of the SXT and LAXPc spectral data in 0.4-20 *** best spectral fit is obtained by a power law model with a photon index(1.7±0.03)with high energy spectral cut-off at 12.9±0.7 keV.A broad iron line at^6.3 keV is detected in the energy *** briefly discuss the implications of these results.

关键词： Be/X ray binary pulsar 4U 0728–25

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A Review on Thermophysical Properties and Nusselt Number Behavior of Al2O3 Nanofluids in Heat Exchangers

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Journal of Thermal Science 2021年第2期30卷 418-431页

作者： ISSA roy Jean college of Engineering West Texas A&M UniversityCanyonTexas 79016USA

During the last several years,the increase in cooling power requirements for heat exchangers have led to an escalation in heat transfer studies being performed on the use of nanofluids as heat transfer ***,limited effort has been attempted to relate and interpret these findings or the anomalies associated with *** paper compiles test data from several studies conducted on different types of heat *** this review,a concentrated effort is spent to clarify the ambiguities regarding the effect of nanoparticle size on the nanofluid thermal conductivity and Nusselt *** show that the nanofluid thermal conductivity is not influenced by the nanoparticle size,but by the clustering of the particles *** less compact the structure of the nanoparticle clustering is,the greater the enhancement in the nanofluid thermal conductivity *** were also compiled to interpret the relation between the nanofluid flow pattern,nanoparticles volume fraction in the base fluid,and the convective heat *** results from the majority of the heat exchanger studies show an increase in the heat transfer coefficient with the increase in nanoparticle volume ***,studies conducted on plate heat exchanges display some *** the majority of the heat exchanger studies with the exception of few,the decrease in the nanoparticle size is shown to result in an enhancement of the bulk fluid Nusselt *** test data also reveal that the effectiveness of the alumina nanoparticles is dependent on the flow *** increase in the nanoparticles concentration is shown to result in an increase in the nanofluid heat transfer enhancement as the fluid is transitioning from laminar to turbulent *** general,the smaller the nanoparticle size is,the greater the enhancement in the fluid Nusselt number is.

关键词： heat exchanger Nusselt number alumina nanofluid

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Molecular therapy for hepatic injury and fibrosis:Where are we?

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World Journal of Gastroenterology 2006年第4期12卷 509-515页

作者： colette c Prosser roy D Yen Jan Wu Transplant Research Institute University of California Davis Medical Center Sacramento CA United States Division of Gastroenterology Hepatology and Nutrition State University of New York at Buffalo Buffalo NY United States

Hepatic fibrosis is a wound healing response, involving pathways of inflammation and fibrogenesis. In response to various insults, such as alcohol, ischemia, viral agents, and medications or hepatotoxins, hepatocyte damage will cause the release of cytokines and other soluble factors by Kupffer cells and other cell types in the liver. These factors lead to activation of hepatic stellate cells, which synthesize large amounts of extracellular matrix components. With chronic injury and fibrosis, liver architecture and metabolism are disrupted, eventually manifesting as cirrhosis and its complications. In addition to eliminating etiology, such as antiviral therapy and pharmacological intervention, it is encouraging that novel strategies are being developed to directly address hepatic injury and fibrosis at the subcellular and molecular levels. With improvement in understanding these mechanisms and pathways, key steps in injury, signaling, activation, and gene expression are being targeted by molecular modalities and other molecular or gene therapy approaches. This article intends to provide an update in terms of the current status of molecular therapy for hepatic injury and fibrosis and how far we are from clinical utilization of these new therapeutic modalities.

关键词： Fibrosis Gene therapy Hepatic stellate cell Hepatocyte Injury

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An Estimation of the Geometrical Structure of Polar cap and Emission Property of Radio Pulsar:A Treatment from an Analytical Approach

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Research in Astronomy and Astrophysics 2023年第4期23卷 44-55页

作者： Tridib roy Indian Institute of Astrophysics Sarjapur Main RoadKoramangala 2nd BlockBangalore 560034India SN Bose National cenre for Basic Science SaltlakeSector 3JD BlockKolkata 700106India

Pulsars are believed to be one of the most interesting objects in the *** emission mechanism of pulsars is still a conundrum to physicists,as there is no completely acceptable theory that can establish a consensus between theory and *** possess a gigantic magnetic field,to the order of 10^(12)Gauss,and generate a very powerful radio beam from the magnetic ***,the powerful radio beam is generated by some complicated coherent plasma processes and acceleration in the pulsar *** location of the origin of the radio waves has been predicted to come out exclusively from the polar cap zone,whose boundary is defined by the footprint of the last open field ***,in this paper,we mainly try to generate the shape of the polar cap structure from an analytical solution and discuss how it gets distorted for different geometrical parameters due to the presence of perturbation such as polar cap current ***,apart from that,we try to emphasize understanding the variation of radio emission height and polarization angle with respect to different geometryrelated parameters as well as with frequency.

关键词： (stars:)pulsars general-stars neutron-radiation mechanisms non-thermal

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