INJECTIVE PARTIAL TRANSFORMATIONS WITH INFINITE DEFECTS

Singha, Boorapa,Sanwong, Jintana,Sullivan, Robert Patrick Korean Mathematical Society 2012 대한수학회보 Vol.49 No.1

In 2003, Marques-Smith and Sullivan described the join ${\Omega}$ of the 'natural order' $\leq$ and the 'containment order' $\subseteq$ on P(X), the semigroup under composition of all partial transformations of a set X. And, in 2004, Pinto and Sullivan described all automorphisms of PS(q), the partial Baer-Levi semigroup consisting of all injective ${\alpha}{\in}P(X)$ such that ${\mid}X{\backslash}X{\alpha}\mid=q$, where $N_0{\leq}q{\leq}{\mid}X{\mid}$. In this paper, we describe the group of automorphisms of R(q), the largest regular subsemigroup of PS(q). In 2010, we studied some properties of $\leq$ and $\subseteq$ on PS(q). Here, we characterize the meet and join under those orders for elements of R(q) and PS(q). In addition, since $\leq$ does not equal ${\Omega}$ on I(X), the symmetric inverse semigroup on X, we formulate an algebraic version of ${\Omega}$ on arbitrary inverse semigroups and discuss some of its properties in an algebraic setting.

Spin Excitations in a 4f−3d Heterodimer on MgO

Singha, A.,Donati, F.,Natterer, F. D.,Wä,ckerlin, C.,Stavrić,, S.,Popović,, Z. S.,Š,ljivanč,anin, Ž,.,Patthey, F.,Brune, H. American Physical Society 2018 Physical review letters Vol.121 No.25

Comparison of Culture Media for In Vitro Maturation of Oocytes of Indigenous Zebu Cows in Bangladesh

Singha, Joydev Kumar,Bhuiyan, Mohammad Musharraf Uddin,Rahman, Mohammad Moshiur,Bari, Farida Yeasmin The Korean Society of Embryo Transfer 2015 한국동물생명공학회지 Vol.30 No.4

The objectives of the present study were to select an effective basic medium including its hormone and protein supplementation for IVM of oocytes of indigenous zebu cows. The ovaries of cows were collected from slaughter house and the follicular fluid was aspirated from 2 to 8 mm diameter follicles. The COCs with more than 3 cumulus cell layers and homogenous cytoplasm were selected for maturation. The oocytes were matured in media for 24 hrs at $39^{\circ}C$ with 5% $CO_2$ in humidified air. The maturation of oocytes was evaluated by examining the presence of first polar body under microscope. An efficient basic medium was determined after culturing COCs in either TCM 199 or SOF medium in Experiment 1. An efficient hormone supplementation was determined after culturing COCs in either FSH or gonadotrophin supplemented TCM 199 in Experiment 2. An efficient protein supplementation was determined after culturing COCs in either FBS or Oestrous cow serum (OCS) supplemented TCM 199 in Experiment 3. The oocyte recovery rate per ovary was 3.35. The overall rate of IVM was 74.6%. The maturation rate was $75.5{\pm}3.9$ and $62.2{\pm}20.2%$ in TCM and SOF medium, respectively (P>0.05). The maturation rate of oocytes was significantly higher ($76.6{\pm}13.2%$) in FSH supplemented medium than gonadotrphin supplemented counterpart ($69.7{\pm}10.8%$) (P<0.05). The maturation rates of oocytes were $81.7{\pm}12.9$ and $85.7{\pm}12.7%$ in medium supplemented with FBS and OCS, respectively (P>0.05). In conclusions, both TCM 199 and SOF supplemented with either FBS or OCS, and FSH may be used as medium for IVM of indigenous zebu oocytes in Bangladesh.

Fluorescence sensing systems for gold and silver species

Singha, Subhankar,Kim, Dokyoung,Seo, Hyewon,Cho, Seo Won,Ahn, Kyo Han The Royal Society of Chemistry 2015 Chemical Society reviews Vol.44 No.13

<P>Besides the noble physical appearance of gold and silver, their novel chemical properties attracted the modern technology for various industrial, chemical and biological uses including medical applications. The widespread use of gold and silver, however, can cause potential hazards to our environment. Therefore, suitable detection methods are a prerequisite for the evaluation of their harmful effects as well as for studying their beneficial biological properties. Due to the several advantages over the conventional analytical methods, the fluorescence detection of gold and silver has become an active research area in recent years. In this review, we provide an overview of the reported fluorescent detection systems for gold and silver species, and discuss their sensing properties with promising features. The future scope of developments in this field of research is also mentioned.</P> <P>Graphic Abstract</P><P>Here, we provide an overview of the reported fluorescent detection systems for gold and silver species, and discuss their sensing properties with promising features. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cs00328d'> </P>

4f occupancy and magnetism of rare-earth atoms adsorbed on metal substrates

Singha, Aparajita,Baltic, Romana,Donati, Fabio,Wä,ckerlin, Christian,Dreiser, Jan,Persichetti, Luca,Stepanow, Sebastian,Gambardella, Pietro,Rusponi, Stefano,Brune, Harald American Physical Society 2017 Physical Review B Vol.96 No.22

<P>We report x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements as well as multiplet calculations for Dy, Ho, Er, and Tm atoms adsorbed on Pt(111), Cu(111), Ag(100), and Ag(111). In the gas phase, all four elements are divalent and we label their 4f occupancy as 4f(n). Upon surface adsorption, and depending on the substrate, the atoms either remain in that state or become trivalent with 4f(n-1) configuration. The trivalent state is realized when the sum of the atomic correction energies (4f -> 5d promotion energy E-fd + intershell coupling energy delta E-c) is low and the surface binding energy is large. The latter correlates with a high substrate density of states at the Fermi level. The magnetocrystalline anisotropy of trivalent RE atoms is larger than the one of divalent RE atoms. We ascribe this to the significantly smaller covalent radius of the trivalent state compared to the divalent one for a given RE element. For a given valency of the RE atom, the anisotropy is determined by the overlap between the spd states of the RE and the d states of the surface. For all investigated systems, the magnetization curves recorded at 2.5 K show absence of hysteresis indicating that magnetic relaxation is faster than about 10 s.</P>

A structural remedy toward bright dipolar fluorophores in aqueous media

Singha, Subhankar,Kim, Dokyoung,Roy, Basab,Sambasivan, Sunderraman,Moon, Hyunsoo,Rao, Alla Sreenivasa,Kim, Jin Yong,Joo, Taiha,Park, Jae Woo,Rhee, Young Min,Wang, Taejun,Kim, Ki Hean,Shin, Youn Ho,Jun Royal Society of Chemistry 2015 Chemical Science Vol. No.

<▼1><P>Structural factors governing the poor emission of dipolar dyes in aqueous media are identified, leading to new acedan derivatives with brighter fluorescence and enhanced two-photon properties.</P></▼1><▼2><P>The donor–acceptor (D–A) type dipolar fluorophores, an important class of luminescent dyes with two-photon absorption behaviour, generally emit strongly in organic solvents but poorly in aqueous media. To understand and enhance the poor emission behaviour of dipolar dyes in aqueous media, we undertake a rational approach that includes a systematic structure variation of the donor, amino substituent of acedan, an important two-photon dye. We identify several factors that influence the emission behaviour of the dipolar dyes in aqueous media through computational and photophysical studies on new acedan derivatives. As a result, we can make acedan dyes emit bright fluorescence under one- and two-photon excitation in aqueous media by suppressing the liable factors for poor emission: 1,3-allylic strain, rotational freedom, and hydrogen bonding with water. We also validate that these findings can be generally extended to other dipolar fluorophores, as demonstrated for naphthalimide, coumarin and (4-nitro-2,1,3-benzoxadiazol-7-yl)amine (NBD) dyes. The new acedan and naphthalimide dyes thus allow us to obtain much brighter two-photon fluorescent images in cells and tissues than in their conventional forms. As an application of these findings, a thiol probe is synthesized based on a new naphthalimide dye, which shows greatly enhanced fluorescence from the widely used <I>N</I>,<I>N</I>-dimethyl analogue. The results disclosed here provide essential guidelines for the development of efficient dipolar dyes and fluorescence probes for studying biological systems, particularly by two-photon microscopy.</P></▼2>

Toward a Selective, Sensitive, Fast-Responsive, and Biocompatible Two-Photon Probe for Hydrogen Sulfide in Live Cells

Singha, Subhankar,Kim, Dokyoung,Moon, Hyunsoo,Wang, Taejun,Kim, Ki Hean,Shin, Youn Ho,Jung, Junyang,Seo, Eunseok,Lee, Sang-Joon,Ahn, Kyo Han American Chemical Society 2015 ANALYTICAL CHEMISTRY - Vol.87 No.2

<P>Hydrogen sulfide has emerged as an exciting endogenous gasotransmitter in addition to nitric oxide and carbon dioxide. Noninvasive detection methods for hydrogen sulfide thus become indispensable tools for studying its diverse roles in biological systems. Accordingly, fluorescent probes for hydrogen sulfide have received great attention in recent years. A practically useful fluorescent probe for bioimaging of hydrogen sulfide should be selective, sensitive, fast-responsive, biocompatible, observable in the biological optical window, and capable of deep-tissue imaging. These sensing properties, however, are extremely difficult to achieve at the same time. Disclosed here is the two-photon fluorescent probe that meets all of these criteria. The probe belongs to a Michael acceptor system, which raised a serious selectivity issue over the competing biothiols such as cysteine and glutathione. We have addressed the selectivity issue by optimizing the electronic and steric interactions between biothiols and the probe, in addition to achieving very high sensitivity, fast-response, and biocompatibility. Also, the sensing mechanism suggested in the literature was revised. The probe thus enables us to image the endogenously produced hydrogen sulfide with negligible interference from other biothiols in live cells. The excellent sensing properties of the probe combined with its capability of bioimaging thus make it a practically useful tool for further studying biological roles of hydrogen sulfide.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2015/ancham.2015.87.issue-2/ac503806w/production/images/medium/ac-2014-03806w_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac503806w'>ACS Electronic Supporting Info</A></P>

Ratiometric Imaging of Tissue by Two-Photon Microscopy: Observation of a High Level of Formaldehyde around Mouse Intestinal Crypts

Singha, Subhankar,Jun, Yong Woong,Bae, Juryang,Ahn, Kyo Han American Chemical Society 2017 ANALYTICAL CHEMISTRY - Vol.89 No.6

<P>Ratiometric imaging by two-photon microscopy can offer a viable tool for the relative quantification of biological analytes inside tissue with minimal influence from environmental factors that affect fluorescence signal. We demonstrate the ratiometric imaging of formaldehyde at the suborgan level using a two-photon fluorescent probe, which involves pixel-to-pixel ratiometric data transformation. This study reveals for the first time a high level of formaldehyde around the crypts of mouse small intestine, implicating its possible protective role along with the released antimicrobials from the Paneth cells.</P>

Composition dependent crossover from ferroelectric to relaxor-ferroelectric in NBT-ST-KNN ceramics

Singha A.,Praharaj S.,Rout S.K.,Rout D. 한국물리학회 2022 Current Applied Physics Vol.36 No.-

Composition driven crossover from ferroelectric (FE) to relaxor-ferroelectric (RFE) is systematically investigated in (0.8-x)(Na0.5Bi0.5)TiO3-0.2SrTiO3-x(K0.5Na0.5)NbO3 (NBT-ST-xKNN) ceramics in the light of ferroelectric and dielectric (ε) response. The appearance of constricted polarization-electric field loop and double current densityelectric field peaks in the proximity of x = 0.02 suggests a co-existence of FE and RFE phases. The system attains a maximumε ~4200 and tan δ < 0.1 at x = 0.02. Broad ε(T) peaks reveal a greater degree of disorder due to KNN substitution and their deconvolution demonstrates three different relaxation/polarization processes related to low and high-temperature nanodomains. The composition with x = 0.1 exhibits maximum broadness in ε(T) profiles resulting in a temperature-insensitive permittivity variation of ±15% (ε125 ◦C,100 kHz~2007) over a span of ~280 ◦ C. A remarkably low (TCε)100kHz of − 75 ppm/◦ C is also achieved for x = 0.1 from 100 to 300 ◦C proposing it to be a potential capacitor material.

Rock physics modeling in sand reservoir through well log analysis, Krishna-Godavari basin, India

Singha, Dip Kumar,Chatterjee, Rima Techno-Press 2017 Geomechanics & engineering Vol.13 No.1

Rock physics modeling of sandstone reservoir from gas fields of Krishna-Godavari basin represents the link between reservoir parameters and seismic properties. The rock physics diagnostic models such as contact cement, constant cement and friable sand are chosen to characterize reservoir sands of two wells in this basin. Cementation is affected by the grain sorting and cement coating on the surface of the grain. The models show that the reservoir sands in two wells under examination have varying cementation from 2 to more than 6%. Distinct and separate velocity-porosity and elastic moduli-porosity trends are observed for reservoir zones of two wells. A methodology is adopted for generation of Rock Physics Template (RPT) based on fluid replacement modeling for Raghavapuram Shale and Gollapalli Sandstones of Early Cretaceous. The ratio of P-wave velocity to S-wave velocity (Vp/Vs) and P-impedance template, generated for this above formations is able to detect shale, brine sand and gas sand with varying water saturation and porosity from wells in the Endamuru and Suryaraopeta gas fields having same shallow marine depositional characters. This RPT predicted detection of water and gas sands are matched well with conventional neutron-density cross plot analysis.