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Purpose: Websites, search engines, recommender systems, artificial intelligence and digital libraries have the potential to support serendipity for unexpected interaction with information and ideas which would lead to favored information discoveries. This paper aims to explore the current state of research into serendipity particularly related to information encountering. Design/methodology/approach: This study provides bibliometric review of 166 studies on serendipity extracted from the Web of Science. Two bibliometric analysis tools HisCite and RStudio (Biblioshiny) are used on 30 years of data. Citation counts and bibliographic records of the papers are assessed using HisCite. Moreover, visualization of prominent sources, countries, keywords and the collaborative networks of authors and institutions are assessed using RStudio (Biblioshiny) software. A total of 166 papers on serendipity were found from the period 1989 to 2022, and the most influential authors, articles, journals, institutions and countries among these were determined. Findings: The highest numbers of 11 papers were published in the year 2019. Makri and Erdelez are the most influential authors for contributing studies on serendipity. “Journal of Documentation” is the top-ranking journal. University College London is the prominent affiliation contributing highest number of studies on serendipity. The UK and the USA are the prominent nations contributing highest number of research. Authorship pattern for research on serendipity reveals involvement of single author in majority of the studies. OA Green model is the most preferred model for archiving of research articles by the authors who worked on serendipity. In addition, majority of the research outputs have received a citation ranging from 0 to 50. Originality/value: To the best of the authors’ knowledge, this paper may be the first bibliometric analysis on serendipity research using bibliometric tools in library and information science studies. The paper would definitely open new avenues for other serendipity researchers.

V imido alkylidenes have been applied for the ring-opening metathesis polymerization involving cyclic olefins. However, those complexes found limited application in reactions with acyclic terminal olefins due to instability toward ethylene. Experimental and theoretical studies show that the β-hydride elimination from unsubstituted metallacyclobutene is the primary decomposition pathway in those systems. Herein, we report the synthesis of the first catalytically active V oxo alkylidene, VO(CHSiMe3)(PEt3)2Cl, which exhibits the highest reported productivity with various terminal olefins in ring-closing metathesis reactions among known V catalysts. Presented DFT studies indicate that β-hydride elimination is significantly disfavored for V oxo species.

A photoactive manganese carbonyl complex derived from dansylimidazole (Imdansyl), namely, [Mn(Imdansyl)(CO)3(phen)](CF3SO3) (1), has been synthesized and structurally characterized. This is the first luminescent manganese carbonyl-based photoCORM reported in the literature. This complex exhibits CO release under the exclusive control of low-power broadband visible light. The corresponding rhenium carbonyl complex, namely, [Re(Imdansyl)(CO)3(phen)](CF3SO3) (2), has also been reported, which is luminescent but sensitive only to UV-B (λ<315 nm) light. The entry of the manganese photoCORM into the human colorectal adenocarcinoma cells (HT-29) has been demonstrated with the aid of fluorescence microscopy. Irradiation of the photoCORM-loaded cancer cells to visible light leads to a dose-dependent apoptotic cell death.

Six [Fe8(μ4-O)4(μ-4-R-pyrazolato)12X4] complexes containing an identical Fe8(μ4-O)4core have been structurally characterized and studied by Mössbauer spectroscopy. In each case, an inner μ4-O bridged FeIIIcubane core is surrounded by four trigonal bipyramidal iron centers, the two distinct sites occurring in a 1:1 ratio. The Mössbauer spectrum of each of the clusters consists of two quadrupole doublets, which, with one exception (X = NCS, R = H), overlap to give three absorption lines. The systematic variation of X and R causes significant changes in the Mössbauer spectra. A comparison with values for the same clusters computed using density functional theory allows us to establish an unequivocal assignment of these peaks in terms of a nested model for the overlapping doublets. The changes in Mössbauer parameters (both experimental and computed) for the 1-electron reduced species [Fe8(μ4-O)4(μ-4-Cl-pyrazolato)12Cl4]−are consistent with a redox event that is localized within the cubane core.

Part of West Bengal, an eastern state of India, was severely affected by a super cyclone Amphan(or Umpun) on May 20, 2020, during 14:30 to 11:00 h IST with a wind speed of 155–160 km/hr and heavy rainfall. During the most intense event, Global Navigation Satellite System (GNSS) data were collected using a compact GNSS module from a location situated extremely close to the cyclone eye path. Severe fluctuation of satellite signal strength for GPS, Galileo, and Beidou signals was observed during the time in the proximity of the cyclone eye. The signal strength fluctuations caused loss of lock for the signals at the receiver resulting in a low number of used satellites and degraded position solution quality. This manuscript presents the findings which were not reported earlier. The results would be useful for understanding the effects of such events, especially for the disaster management efforts during such events in the cases where GNSS is used.

Recent years have seen rapid growth in utilizing vegetable oils to derive a wide variety of polymers to replace petroleum-based polymers for minimizing environmental impact. Nonedible castor oil (CO) can be extracted from castor plants that grow easily, even in an arid land. CO is a promising source for developing several polymers such as polyurethanes, polyesters, polyamides, and epoxy-polymers. Several synthesis routes have been developed, and distinct properties of polymers have been studied for industrial applications. Furthermore, fillers and fibers, including nanomaterials, have been incorporated in these polymers for enhancing their physical, thermal, and mechanical properties. This review highlights the development of CO-based polymers and their composites with attractive properties for industrial and biomedical applications. Recent advancements in CO-based polymers and their composites are presented along with a discussion on future opportunities for further developments in diverse applications.

Herein we report the synthesis, characterization, and cellular internalization properties of two visible-light active luminescent Mn-based photoCORMs. The enhanced membrane permeability of the photoactive Mn carbonyl complex (photoCORM) derived from a designed lipophilic ligand namely, [Mn(CO)3(Imdansyl)(L1)](CF3SO3) (1) (where L1= a diazabutadiene-based ligand containing two highly lipophilic adamantyl motifs, Imdansyl = dansylimidazole) promoted rapid internalization within human colorectal adenocarcinoma (HT-29) cells compared to [Mn(CO)3(Imdansyl)(L2)](CF3SO3) (2) (where L2= a diazabutadiene ligand bearing two hydrophilic 1,3,5-triazaadamantyl group). Colocalization experiments using membrane stain indicate different extents of localization of the two CO complexes within the cellular matrix. Visible-light triggered CO release from the lipophilic photoCORM induced caspase-3/7 activation on HT-29 cells, which was detected using confocal microscopy. The rapid accumulation of the lipophilic photoCORM 1in the cellular membrane resulted in more efficient CO-induced cell death compared to the hydrophilic analogue 2.

Two trinuclear CuIIpyrazolato complexes with a Cu3(μ3-E)-core (E = O2–or OH–) and terminal nitrite ligands in two coordination modes were characterized crystallographically, spectroscopically, and electrochemically. One-electron oxidation of the μ3-O species produces a delocalized, mixed-valent, formally CuII2CuIII-nitrite, but no nitrate. In contrast, under reducing conditions—addition of PhSH as an electron and proton donor—both complexes mediate the reduction of nitrite, releasing NO.

Microbial invasion and colonization of the skin and underlying soft tissues are among the most common types of infections, becoming increasingly prevalent in hospital settings. Systemic antibiotic chemotherapies are now extremely limited due to emergence of drug-resistant Gram-positive and multidrug-resistant Gram-negative bacterial strains. Topical administration of antimicrobials provides an effective route for the treatment of skin and soft tissue infections (SSTIs). Therefore, the development of new and effective materials for the delivery of these agents is of paramount importance. Silver is a broad-spectrum antibiotic used for the treatment and prevention of infections since ancient times. However, the high reactivity of silver cation (Ag+) makes its incorporation into delivery materials quite challenging. Herein we report a novel soft agar hydrogel composite for the delivery of Ag+into infected wound sites. This material incorporates a Ag(I) complex [Ag2(DSX)2(NO3)2] (1; DSX = 5-(dimethylamino)-N,N-bis(pyridin-2-ylmethyl) naphthalene-1-sulfonamide) that exhibits a change in fluorescence upon Ag+release and qualitatively indicates the end point of silver delivery. The antibacterial efficacy of the material was tested against several bacterial strains in an SSTI model. The complex 1–agar composite proved effective at eradicating the pathogens responsible for the majority of SSTIs. The theranostic (therapeutic/diagnostic) properties coupled with its stability, softness, ease of application, and removal make this material an attractive silver-delivery vehicle for the treatment and prevention of SSTIs.

Three new α-hydroxy carboxylate group functionalized MnFe2O4nanoparticles (NPs) have been developed to explore the microscopic origin of ligand modified fluorescence and magnetic properties of nearly monodispersed MnFe2O4NPs. The surface functionalization has been carried out with three small organic ligands (tartrate, malate, and citrate) having different number of α-hydroxy carboxylate functional group along with steric effect. Detailed study unveils that α-hydroxy carboxylate moiety of the ligands plays key role to generate intrinsic fluorescence in functionalized MnFe2O4NPs through the activation of ligand to metal charge transfer transitions, associated with ligand–Mn2+/Fe3+interactions along with d–dtransition corresponding to d–orbital energy level splitting of Fe3+ions on NP surface. Further, MnFe2O4NPs show a maximum 140.88% increase in coercivity and 97.95% decrease in magnetization compared to its bare one upon functionalization. The ligands that induce smallest crystal field splitting of d–orbital energy level of transition metal ions are found to result in strongest ferrimagnetic activation of the NPs. Finally, our developed tartrate functionalized MnFe2O4(T-MnFe2O4) NPs have been utilized for studying DNA binding interaction and nuclease activity for stimulating their beneficial activities toward diverse biomedical applications. The spectroscopic measurements indicate that T-MnFe2O4NPs bind calf thymus DNA by intercalative mode. The ability of T-MnFe2O4NPs to induce DNA cleavage was studied by gel electrophoresis technique where the complex is found to promote the cleavage of pBR322 plasmid DNA from the super coiled form I to linear coiled form II and nicked coiled form III with good efficiency.

Silver(I) complexes of two designed tridentate ligands, namely, 2,6-(pyridyl)iminoditriazaadamantane (pydTAm) and 2,6-(pyridyl)iminodiadamantane (pydAm), have been synthesized and structurally characterized. [Ag(pydTAm)2](CF3SO3) (1), the hitherto unknown merisomer of a silver(I) octahedral complex, crystallizes in a highly symmetric body-centered cubic I4̅3mspace group. Quite in contrast, the AgIcenter in the analogous [Ag(pydAm)2](CF3SO3) (2) complex resides in a trigonal-bipyramidal geometry and crystallizes in a triclinic P1̅ space group with two crystallographically independent molecules in the asymmetric unit. Complex 1exhibits exceptional solubility in aqueous media and leads to the efficient eradication of several bacterial strains upon sustained release of bioactive silver.

A family of Re(I) carbonyl complexes of general formula [ReX(CO)3(phen)]0/1+(where X = Cl–, CF3SO3–, MeCN, PPh3, and methylimidazole) derived from 1,10-phenanthroline (phen) exhibits variable emission characteristics depending on the presence of the sixth ancillary ligand/group (X). All complexes but with X = MeCN exhibit moderate CO release upon irradiation with low-power UV light and are indefinitely stable in anaerobic/aerobic environment in solution as well as in solid state when kept under dark condition. These CO donors liberate three, one, or no CO depending on the nature of sixth ligand upon illumination as studied with the aid of time-dependent IR spectroscopy. Results of excited-state density functional theory (DFT) and time-dependent DFT calculations provided insight into the origin of the emission characteristics of these complexes. The luminescent rheinum(I) photoCORMs uniformly displayed efficient cellular internalization by the human breast adenocarcinoma cells, MDA-MB-231, while the complex with PPh3as ancillary ligand showed moderate nuclear localization in addition to the cytosolic distribution. These species hold significant promise as theranostic photoCORMs (photoinduced CO releasing molecules), where the entry of the pro-drug can be tracked within the cellular matrices.

Two manganese(I) carbonyl complexes derived from 2-(pyridyl)benzothiazole (pbt) and 1,10-phenanthroline (phen) release carbon monoxide (CO) under low-powerbroad-band visible-lightillumination. CO photorelease from [Mn(CO)3(pbt)(PTA)]CF3SO3(1, where PTA = 1,3,5-triaza-7-phosphaadamantane) is accompanied by an emergence of a strong fluorescence around 400 nm from almost nonfluorescent preirradiated 1. However, [Mn(CO)3(phen)(PTA)]CF3SO3(2) showed no such phenomenon upon prolonged illumination under similar experimental conditions. The two analogous rhenium(I) complexes, namely, [Re(CO)3(pbt)(PTA)]CF3SO3(3) and [Re(CO)3(phen)(PTA)]CF3SO3(4), have also been synthesized and characterized to compare their photo properties with the manganese congeners. Complexes 3and 4exhibit moderate CO release upon irradiation with low-power UV light. All four complexes are highly soluble in anaerobic/aerobic aqueous media and are also considerably more stable when kept under dark conditions. The inherently luminescent rhenium complex 3was utilized to demonstrate cellular internalization of these types of compounds by MDA-MB-231 (human breast cancer) cells, while the two biocompatible manganese(I) complexes (1and 2) have been applied to assess the cell viability of these malignant cells upon CO delivery.

•Eosinophilic meningities is a rare case reported in posterior fossa meningioma.•Diagnostic dilemma.•High degree of clinical suspicion for physician to diagnose.•Removal of the agent causing eosinophilic meningities is the definitive treatment.•Steroid is to be used in case of above clinical setting.

A Re(I) carbonyl complex derived from 2-(2-pyridyl)-benzothiazole (pbt), [Re(H2O)(CO)3(pbt)](CF3SO3) (1), rapidly releases CO under low-power UV illumination. CO photorelease from 1is accompanied by a change in luminescence from orange to deep blue. These two distinct luminescence signals have been successfully employed to track (a) the entry of the pro-drug 1into cancer cells and (b) the end of the CO (drug) delivery step within the target.

Crawford and Sobel (Econometrica 50(6):1431–1451, 1982) is a seminal contribution that introduced the study of costless signalling of privately held information by an expert to a decision maker. Among the chief reasons for its widespread application is the comparative statics they develop between the extent of strategically transmitted information and the degree of conflict in the two players’ preferences. This paper completes their analysis by establishing that in their general model, almost full revelation obtains as the two players’ preferences get arbitrarily close to each other.

Objectives:We carried out a study to assess the prevalence of goitre, measure urinary iodine excretion (UIE) levels and to estimate salt iodine content at the household level in Howrah district of West Bengal, India.Methods:Study Design: This is a Cross-sectional descriptive study conducted in September–December 2006. Setting: Primary schools located in 30 clusters (villages and wards) randomly selected through <5001>30 cluster<5002> sampling methodology. Participants: 2400 school children, aged 8–10 years. Indicators: The indicators used in this study to assess for IDD were recommended by the WHO/UNICEF/ICCIDD. Goitre was assessed clinically by the standard palpation technique. The urinary iodine excretion level was analyzed by the wet digestion method. Salt samples consumed at the household level were collected and tested by the spot iodine testing kit to measure iodine content.Results:The Total Goitre Rate (TGR) was 13.7% (95% CI = 12.3–15.1%). Grade 1 was 11.4% and Grade 2 (visible goitre) was 2.3%. The TGR was influenced by the age and sex factors but not by religion and residence. The median urinary iodine excretion level was 13 μg/dL (normal range: 10–20 μg/dL) and none had a value less than 5 μg/dL. There was significant negative correlation between UIE levels and the age and place of residence factors. Almost 80% of salt samples tested had adequate iodine content (≥ 15 ppm). Consumption of iodized salts was lower among Hindus and in rural area.Conclusion:In conclusion, the Howrah district is in a transition phase from iodine deficiency to iodine sufficiency.

Abstract: Banded iron-formations (BIF) form an important part of the Archean supracrustal belts of the Jharkhand-Orissa region, India. Major, trace and REE chemistry of the banded iron-formation of the Gandhamardan, Deo Nala, Gorumahisani and Noamundi sections of the Jharkhand-Orissa region are utilized to explore the source of metals and to address the thermal regime of the basin floor and the redox conditions of the archean sea. Hydrothermal fluids of variable temperatures might have contributed the major part of the Fe and other trace elements to the studied banded iron-formations. Diagenetic fluids from the sea floor sediments and river water might have played a subdued role in supplying the Fe and other elements for the banded iron-formations.

Abstract: Cobalt disulfide is an important nanomaterial in the field of material chemistry due to its interesting catalytic and electromagnetic properties. We herein report the simple solution phase preparation of nanoparticles of cobalt disulfide in micellar medium of cationic surfactant cetyltrimethylammonium bromide (CTAB) and also by way of capping with thiophenol. The product has been characterized using spectroscopic and electron microscopic and magnetic moment measurements. The presence of disulfide bond is clearly evident from the 480 cm−1 peak in the infrared spectrum. The thiol passivated particles prepared in aqueous and ethanol medium has been found to have different compositions as observed from the ESIMS study.

Interaction between polymer and surfactant bearing opposite charges is much more complex from a physicochemical point of view as compared to interaction between ionic surfactant and nonionic polymer. Electrostatic and hydrophobic interactions interplay in the former, whereas the hydrophobic effect is the prevailing factor in the latter. We have studied the interaction between a water-soluble polyanion, sodium salt of carboxymethylcellulose (NaCMC), with a cationic amphiphile, CTAB, in aqueous medium. There were manifold discrepancies with the reported works in NaCMC-alkyltrimethylammonium bromide, which is assumed to be an effect of difference in degree of substitution, which in turn affects the charge density of the polymer chain. We have noticed that the bulk complexation and interfacial interaction driven by electrostatic forces operate side by side. Thereafter, there is a wrapping process by the polyanion to the polymer-induced smaller surfactant aggregates driven by increase in entropy of the solution as a result of expulsion of the counterions from the ionic atmosphere around the surfactant aggregate. Because of the electrostatic interaction, hydrophobicity of the polymer-surfactant complex increases, leading to coacervation, and again solubilization in the hydrophobic core of the self-aggregated structure provided by the added excess CTAB. The tensiometric, conductometric, microcalorimetric, and turbidimetric techniques have been applied to address these problems.

Iodine deficiency disorders (IDD) are major public health problems in India, including West Bengal. Existing programme to control IDD needs to be continuously monitored through recommended methods and indicators. The objective of this study was to assess the prevalence of goitre, status of urinary iodine excretion (UIE) level and to estimate iodine content of salts at the household level in Purulia district, West Bengal. A school-based, cross-sectional study was conducted during June-September 2005; among 2400 school children, aged 8–10 years. The ‘30 cluster’ sampling methodology and indicators for assessment of IDD, as recommended by the joint WHO/UNICEF/ICCIDD consultation, were utilized for the study. Goitre was assessed by standard palpation technique, urinary iodine excretion was analyzed by wet digestion method and salt samples were tested by spot iodine testing kit. The total goitre rate (TGR) was 25.9% (95% Cl=24.1–27.1%) with grade I and grade II (visible goitre) being 19.5% and 6.4% respectively. Goitre prevalence did not differ by sex but significant difference was observed in respect of age. Median urinary iodine excretion level was 9.25 μg/dl and 31.6% children had value less than 5 μg/dl. Only 33.4% of the salt samples tested had adequate iodine content of ≥ 15 ppm, High goitre prevalence (25.9%) and median urinary iodine (9.25 μ g/dl) below normal range indicate existence of current iodine deficiency in Purulia district. The district is still in the iodine-deficient state. Moreover, salt iodisation level far below the recommended goal highlights IDD as major public health problems in the district. Intensified information, education and communication activities along with sustained monitoring are urgently required.

The synthesis of imidorhenium(V) [Re(NAr)Cl3(L)] complexes is reported. Their reaction with dilute HNO3furnishes [Re(NAr)Cl3(L′)] species incorporating monoionized iminoamide ligands (the ligands are abbreviated as L and L′ respectively). The iminoamide complexes exhibit sextet EPR spectra in CH2Cl2solution at room temperature. They are electroactive in MeCN solution and to display two quasi reversible responses near 0.2 and 1.6 V which can be attributed to ReV→ReVIand ReVI→ ReVIIoxidations respectively. One of the [Re(NAr)Cl3(L)] complexes has been structurally characterized. The transinfluence of the amide nitrogen considerably lengthens the Re–N bond lying transto the imido group. The triply bonded ReN–C moiety is linear.The synthesis of imidorhenium(V) [Re(NAr)Cl3(L)] complexes is reported. Their reaction with dilute HNO3furnishes [Re(NAr)Cl3(L′)] species incorporating monoionized iminoamide ligands (the ligands are abbreviated as L and L′ respectively). The iminoamide complexes exhibit sextet EPR spectra in CH2Cl2solution at room temperature. They are electroactive in MeCN solution and to display two quasi reversible responses near 0.2 and 1.6 V which can be attributed to ReV→ReVIand ReVI→ ReVIIoxidations respectively. One of the [Re(NAr)Cl3(L)] complexes has been structurally characterized. The transinfluence of the amide nitrogen considerably lengthens the Re–N bond lying transto the imido group. The triply bonded ReN–C moiety is linear.

Abstract CdS is a large band gap material compared to HgS. Both are interesting from academic and technological points of view. The nanodispersions (colloids) of CdS and HgS as well their core-shell products and composites (co-colloids) were prepared by varied modes of precursor addition in micellar solution of cationic surfactant cetyltrimethylammonium bromide (CTAB). The prepared dispersions were studied by spectroscopic and electron microscopic techniques.

Abstract Colloidal nanodispersion of lead sulfide has been prepared in the aqueous compartments of water/AOT/n-heptane. Compartmentalization has prevented growth and coagulation of particles in the dispersion. The uv–vis and fluorescence spectral measurements of the colloidal PbS dispersion were taken. Particle size has been determined by laser light scattering, transmission electron microscopy and absorption spectroscopy. The effects of temperature, ω (water/AOT mole ratio), [AOT], and [PbS] on the particle size have been examined. The nanodispersed particles in microemulsion capped with thiophenol and dodecanethiol were isolated and characterized by the TEM and FTIR methods.

Abstract: The title transformations are oxygen atom transfer, twin isomerization and regiospecific imine oxidation.Bispyridyldiazole ligands have furnished new oxygen atom transfer reagents of coordination type ReVOCl3(NN) which undergo a slower transfer to PPh3 than the corresponding azole reagents. The rate of twin isomerization (linkage and geometrical) of meridional azole complexes of coordination type ReIII(OPnP)Cl3(NN) to facial ReIII(PnPO)Cl3(NN) decreases rapidly asn increases in the interval 1–4 (PnP is Ph2P(CH2)nPPh2). An α-diimine chelate of type ReV(NPh)Cl3(NN) is shown to undergo facile oxidation to the corresponding iminoamide complex ReVI(NPh)Cl3(NN) upon treating with dilute nitric acid. The reaction proceeds via regiospecific nucleophilic addition of waterto the more polarized imine function.

The spontaneous reaction of [ReO(OEt)I2(PPh3)2] with 2,2'-azobipyridine (L) in acetonitrile, and of [ReOCl3(PPh3)2] with L in toluene, proceeds stereospecifically furnishing the green tris-chelate [Re^IL3]I (1) and the red bis-chelate [Re^IICl2L2] (2), respectively. A structure determination reveals that the coordination geometry of 1 is facial and that of 2 is cis(Cl,Cl)-trans(N^p,N^p)-cis(N^a,N^a) (N^p is a pyridine nitrogen and N^a is an azo nitrogen). The isomer preference is exclusive in both cases and no other isomer has been observed. The average N−N distance in both compounds is about 1.35 Å, signifying the presence of strong d(Re)-π*(azo) back-bonding which plays a crucial role in controlling isomer specificity. The bis-chelate 2 is a one-electron paramagnet and displays a six-line EPR spectrum in fluid solution with g = 2.080 and A = 320 G. The ¹H NMR spectrum of diamagnetic 1 is consistent with the facial geometry. In acetonitrile solution 1 displays an Re^II/Re^I couple and 2 an Re^III/Re^II couple, the reduction potentials being 0.60 and 0.50V vs. SCE respectively. The violet-coloured imide complex [Re^VCl3(NC6H4Cl-p)L] (3) is also reported; it displays an Re^VI/Re^V redox wave at 1.33 V vs. SCE. The stabilization of the lower rhenium oxidation states in 1 and 2 is consistent with the decrease of metal reduction potential with progressive L chelation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)