A modified Waldron test based on sliding skewness for determining asymmetric cycle in a turbidite section

Basab Mukhopadhyay,Partha Pratim Chakraborty,Tapan Majumder 한국지질과학협의회 2004 Geosciences Journal Vol.8 No.2

The non-parametric ‘sign-of-difference’ Waldron test, conventionally used for identifying asymmetric cyclicity (thinningor thickening-up) in turbidite successions, often fails to offer convincing results either when bed thickness distribution is lognormal or where positive and negative cycles are present in equal abundance. A modified Waldron test based on sliding skewness method (taking a number of bed thickness at a time) is proposed here for determining asymmetric cycles in turbidite successions, which appears to be random in their bed thickness distribution based on conventional Waldron test. The method has been tested on two turbidite sections, which belong to two different settings of a single submarine fan system (Andaman Flysch Fan) that is known to have a lognormal bed thickness distribution. Application of the sliding skewness methodology reveals thinning-upward asymmetric cycles in both of these sections, which corroborate with the field observations and paleoenvironmental interpretations. Statistical significance for the proposed methodology was determined on the studied sections both through the Z-value and appropriate two-tailed null hypothesis. It is proposed that the result (thickening or thinning upward) is invariant with the interval (number of bed thickness taken for calculation) chosen for the sliding skewness calculation. This new method can be used on bed thickness measurement data from any turbidite succession in addition to other tests for identifying asymmetric cyclicity where non-parametric Waldron Test fails.

Mononuclear Zn(<small>II</small>)- and Cu(<small>II</small>)-complexes of a hydroxynaphthalene-derived dipicolylamine: fluorescent sensing behaviours toward pyrophosphate ions

Roy, Basab,Rao, Alla Sreenivasa,Ahn, Kyo Han Royal Society of Chemistry 2011 Organic & Biomolecular Chemistry Vol.9 No.22

<P>Mononuclear Zn(<SMALL>II</SMALL>)-DPA and Cu(<SMALL>II</SMALL>)-DPA complexes crafted on 2-hydroxy-6-cyanonaphthalene fluorophore selectively recognize PPi over ATP and other anions including inorganic phosphates in aqueous medium, showing turn-on type fluorescence enhancements. Coordination of a hydroxyl group of the fluorophore, directly or in alkoxy form, to the central metal ion is crucial for the sensing processes. Both the complexes elicit a fluorescence increase in a time-dependent fashion.</P> <P>Graphic Abstract</P><P>Two mononuclear Zn(<SMALL>II</SMALL>)-DPA and Cu(<SMALL>II</SMALL>)-DPA complexes crafted on a 2-hydroxy-6-cyanonaphthalene fluorophore are synthesized; they selectively sense pyrophosphates (PPi) over ATP, phosphates, and other anions in aqueous medium, showing 17–24 times fluorescence enhancement. Both the complexes elicit fluorescence increase in a time-dependent fashion. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1ob05999h'> </P>

“Turn-on” fluorescent sensing with “reactive” probes

Eun Jun, Mi,Roy, Basab,Han Ahn, Kyo Royal Society of Chemistry 2011 Chemical communications Vol.47 No.27

<P>Chemical probes are valuable tools for the investigation of biochemical processes, diagnosis of disease markers, detection of hazardous compounds, and other purposes. Therefore, the development of chemical probes continues to grow through various approaches with different disciplines and design strategies. Fluorescent probes have received much attention because they are sensitive and easy-to-operate, in general. To realize desired selectivity toward a given analyte, the recognition site of a fluorescent probe is designed in such a way to maximize the binding interactions, usually through weak molecular forces such as hydrogen bonding, toward the analyte over other competing ones. In addition to such a supramolecular approach, the development of fluorescent probes that sense analytes through chemical reactions has witnessed its usefulness for achieving high selectivity, in many cases, superior to that obtainable by the supramolecular approach. Creative incorporations of the reactive groups to latent fluorophores have provided novel chemical probes for various analytes. In this feature article, we overview the recent progress in the development of turn-on fluorescent probes that are operating through chemical reactions triggered by target analytes. Various chemical reactions have been implemented in the development of many reactive probes with very high selectivity and sensitivity toward target analytes. A major emphasis has been focused on the type of chemical reactions utilized, with the hope that further explorations can be made with new chemical reactions to develop reactive probes useful for various applications.</P> <P>Graphic Abstract</P><P>The reaction-based approach has demonstrated to be valuable in the development of turn-on type fluorescent probes for various target analytes with high selectivity and sensitivity. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1cc00014d'> </P>

A “Reactive” Ratiometric Fluorescent Probe for Mercury Species

Santra, Mithun,Roy, Basab,Ahn, Kyo Han American Chemical Society 2011 Organic letters Vol.13 No.13

<P>A ratiometric fluorescent probe for mercury species is developed based on the metal-promoted hydrolysis of a vinyl ether derivative of 2-(benzothiazol-2-yl)phenol in a buffer solution. The probe responds selectively to mercury species over various other metal ions with a marked fluorescence change from blue to cyan through the excited state intramolecular proton transfer (ESIPT) process. The fluorescence titration is complete with 0.5 equiv of HgCl<SUB>2</SUB>, which indicates that the probe also responds to organomercury species, RHgCl.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2011/orlef7.2011.13.issue-13/ol2011693/production/images/medium/ol-2011-011693_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol2011693'>ACS Electronic Supporting Info</A></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>

Sustainable mold biomachining for the manufacturing of microfluidic devices

Arrate Santaolalla,Yara Alvarez-Braña,Astrid Barona,Lourdes Basabe-Desmonts,Fernando Benito-Lopez,Naiara Rojo 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-

Biomachining has been investigated as a sustainable and effective alternative to conventional prototypingtechniques for molding polymeric materials for their subsequent use as microfluidic devices. A noveland simple process based on the combination of a Pressure Sensitive Adhesive mask and a varnish hasbeen proposed for preparing metal workpieces as an alternative to photolithography, with the latterbeing the most widely used technique for protecting workpieces. As far as the bioprocess is concerned,it has been applied in successive mold-etching and oxidant bio-regeneration stages. Metal solubilizationhas proven to be repeatable in several consecutive mold-etching stages when using the regenerated oxidantsolution. As a result, the lifespan of the biomachining medium has been prolonged, contributing toprocess sustainability. An equation with two restrictions has been proposed to predict the time requiredto obtain a mold with a fixed height, as metal solubilization evolves differently between the first and subsequenthours. Finally, the bio-engraved copper pieces have acted as effective molds in the fabrication ofself-powered polydimethylsiloxane microfluidic devices. This new biomachining application is thereforean effective and ecofriendly process for producing microfluidic devices.

Concomitant polymorphism of an antiferromagnetically coupled dicopper(II,II) complex with single strand helical assembly: Synthesis, structure, DSC, magnetic and heterogeneous catalytic studies

Mijanuddin, Md.,Jana, Atish Dipankar,Drew, Michael G.B.,Hong, Chang Seop,Chattopadhyay, Basab,Mukherjee, Monika,Nandi, Mahasweta,Bhaumik, Asim,Helliwell, Madeline,Mostafa, Golam,Ali, Mahammad Elsevier 2009 Polyhedron Vol.28 No.4

<P><B>Graphical abstract</B></P><P>Two concomitant polymorphic coordination complexes (<B>I</B> and <B>II</B>) have been characterized crystallographically. Complex <B>I</B> shows the presence of a strong antiferromagnetic interaction and good catalytic efficiency in the liquid phase partial oxidation of olefins when immobilized on 2D-hexagonal mesoporous silica.</P><ce:figure></ce:figure> <P><B>Abstract</B></P><P>Two concomitant polymorphic coordination complexes (dark blue – <B>I</B> and black – <B>II</B>) with the formula (Cu<SUB>2</SUB>C<SUB>44</SUB>H<SUB>60</SUB>N<SUB>4</SUB>O<SUB>4</SUB>) have been synthesized and characterized crystallographically. Magnetic measurements show the presence of a strong antiferromagnetic interaction and the 2<I>J</I> value corresponds extremely well to the theoretically calculated one, indicating the fact that it follows nicely the magneto-structural relationship. Immobilization of the copper(II) complex <B>1</B> on a 2D-hexagonal mesoporous silica showed good catalytic efficiency in the liquid phase partial oxidation of olefins in the presence of TBHP as an oxidant.</P>