Microwave-Assisted Synthesis of ZnO-rGO Core-Shell Nanorod Hybrids with Photo- and Electro-Catalytic Activity.

The unique two-dimensional structure and surface chemistry of reduced graphene oxide (rGO) along with its high electrical conductivity can be exploited to modify the electrochemical properties of ZnO nanoparticles (NPs). ZnO-rGO nanohybrids can be engineered in a simple new two-step synthesis, which is both fast and energy-efficient. The resulting hybrid materials show excellent electrocatalytic and photocatalytic activity. The structure and composition of the as-prepared bare ZnO nanorods (NRs) and the ZnO-rGO hybrids have been extensively characterised and the optical properties subsequently studied by UV/Vis spectroscopy and photoluminescence (PL) spectroscopy (including decay lifetime measurements). The photocatalytic degradation of Rhodamine B (RhB) dye is enhanced using the ZnO-rGO hybrids as compared to bare ZnO NRs. Furthermore, potentiometry comparing ZnO and ZnO-rGO electrodes reveals a featureless capacitive background for an Ar-saturated solution whereas for an O2 -saturated solution a well-defined redox peak was observed using both electrodes. The change in reduction potential and significant increase in current density demonstrates that the hybrid core-shell NRs possess remarkable electrocatalytic activity for the oxygen reduction reaction (ORR) as compared to NRs of ZnO alone.

Compound Heterozygote of Hb S (HBB: c.20A>T)/Hb Westdale (HBB: c.380_396delTGCAGGCTGCCTATCAG): Report of Four Cases from Odisha State, India.

We report four cases of compound heterozygotes for Hb S (HBB: c.20A>T) and a rare ß0-thalassemia (ß0-thal) mutation, Hb Westdale (HBB: c.380_396delTGCAGGCTGCCTATCAG), characterized by a 17 bp deletion between codons 126 to 131 in exon 3 of the ß-globin gene of human hemoglobin (Hb) confirmed by direct ß-globin gene sequencing. All four cases were from four unrelated families belonging to the Agharia caste, an endogamous ethnic community of the Sundargarh and Jharsuguda districts of Odisha State, India. Detailed observations indicated that all four cases of Hb S/Hb Westdale were clinically severe. On family screening, six family members were found to be heterozygous for Hb Westdale and were asymptomatic. Deletional α-thalassemia (α-thal) and XmnI polymorphism were studied for all the Hb Westdale cases. The Hb S/Hb Westdale cases had an early median age at onset of symptoms and presentation, more requirement of blood transfusions, splenomegaly and hepatomegaly and were found to be clinically more severe when compared with the Hb S-ß-thal with IVS-I-5 (G>C) (HBB: c.92 + 5G>C) cases. Overall, the findings indicate that this rare and hitherto unreported compound heterozygosity of Hb S/Hb Westdale is a clinically significant hemoglobinopathy and its finding in a large endogamous community of Odisha State, India will have important implication in the epidemiology and understanding of the clinical spectrum of sickle cell disease in Indian context and prenatal diagnosis.

Study of Optical and Magnetic Properties of Graphene-Wrapped ZnO Nanoparticle Hybrids.

In this work, we report a one-step method for the preparation of graphene-wrapped zinc oxide (ZnO) nanoparticle (NP) (ZnO@G) hybrids. These hybrids are characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, optical absorption measurements, photoluminescence (PL) emission spectroscopy, and M-H hysteresis measurements. All results reveal that the ZnO NPs are entirely covered with graphene sheets. In the PL spectra, the quenching of the band gap emission and the enhanced green emission serve as evidence of the electron transfer from the ZnO NPs to the graphene layer. The increase of the room-temperature magnetization of the hybrid, compared to pure ZnO NPs, is due to the increasing defect concentration. We suggest a band diagram model that accounts for these observations. We present the simple wet-chemical synthesis procedure to open a new way for the synthesis of NP-graphene hybrid systems having magnetic properties giving the large manifold potential application.

Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn).

Six trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn) derived from the Schiff base ligand, H2L (2 + 1 condensation product of salicylaldehyde and trans-1,2-diaminocyclohexane) are reported in this investigation. The composition of the metal complexes are [{CuIIL(ClO4)}2CuII(H2O)]·2H2O (1), [{CuIIL(ClO4)}{NiII(H2O)2}{CuIIL}]ClO4·CH3COCH3 (2), [{CuIIL(ClO4)}{CoII(CH3COCH3)(H2O)}{CuIIL(CH3COCH3)}]ClO4 (3) and isomorphic [{CuIIL(ClO4)}2MII(CH3OH)2] (4, M = Fe; 5, M = Mn; 6, M = Zn). Two copper(ii) ions in 1-6 occupy N2O2 compartments of two L2- ligands, while the second metal ion occupies the O(phenoxo)4 site provided by the two ligands, i.e., the two metal ions in both CuIIMII pairs are diphenoxo-bridged. Positive ESI-MS of 1-6 reveals some interesting features. Variable-temperature and variable-field magnetic studies reveal moderate or weak antiferromagnetic interactions in 1-6 with the following values of magnetic exchange integrals (H = -2JS 1 S 2 type): J 1 = -136.50 cm-1 and J = 0.00 for the CuIICuIICuII compound 1; J 1 = -22.16 cm-1 and J = -1.97 cm-1 for the CuIINiIICuII compound 2; J 1 = -14.78 cm-1 and J = -1.86 cm-1 for the CuIICoIICuII compound 3; J 1 = -6.35 cm-1 and J = -1.17 cm-1 for the CuIIFeIICuII compound 4; J 1 = -6.02 cm-1 and J = -1.70 cm-1 for the CuIIMnIICuII compound 5; J = -2.25 cm-1 for the CuIIZnIICuII compound 6 (J is between two CuII in the N2O2 compartments; J 1 is between CuII and MII through a diphenoxo bridge).

Synthesis of graphene-transition metal oxide hybrid nanoparticles and their application in various fields.

Single layer graphite, known as graphene, is an important material because of its unique two-dimensional structure, high conductivity, excellent electron mobility and high surface area. To explore the more prospective properties of graphene, graphene hybrids have been synthesised, where graphene has been integrated with other important nanoparticles (NPs). These graphene-NP hybrid structures are particularly interesting because after hybridisation they not only display the individual properties of graphene and the NPs, but also they exhibit further synergistic properties. Reduced graphene oxide (rGO), a graphene-like material, can be easily prepared by reduction of graphene oxide (GO) and therefore offers the possibility to fabricate a large variety of graphene-transition metal oxide (TMO) NP hybrids. These hybrid materials are promising alternatives to reduce the drawbacks of using only TMO NPs in various applications, such as anode materials in lithium ion batteries (LIBs), sensors, photocatalysts, removal of organic pollutants, etc. Recent studies have shown that a single graphene sheet (GS) has extraordinary electronic transport properties. One possible route to connecting those properties for application in electronics would be to prepare graphene-wrapped TMO NPs. In this critical review, we discuss the development of graphene-TMO hybrids with the detailed account of their synthesis. In addition, attention is given to the wide range of applications. This review covers the details of graphene-TMO hybrid materials and ends with a summary where an outlook on future perspectives to improve the properties of the hybrid materials in view of applications are outlined.

First Report of Hb Limassol [ß8(A5)Lys→Asn; HBB: c.27G>C] from Odisha, India.

In this short report, we describe the clinical presentation of a rare hemoglobin (Hb) variant, Hb Limassol [ß8(A5)Lys→Asn; HBB: c.27G>C] with a faster electrophoretic mobility than Hb A and that elutes in the P3 window on cation exchange high performance liquid chromatography (HPLC). This sequence variation at codon 8 (AAG>AAC) of the HBB gene was found in the four heterozygous cases, all of whom were clinically asymptomatic.

Evaluation of PARKIN gene variants in West Bengal Parkinson's disease patients.

Little information is available regarding the molecular pathogenesis of Parkinson's disease (PD) among the Bengalee population in West Bengal, India. This study was undertaken to determine the contribution of Parkin variants in well-defined ethnically identical Bengalee population of India and further to describe the clinical spectrum associated with these mutations. A total of 150 unrelated PD patients and 150 controls were recruited for the study. The entire cohort was screened for mutations in all the 12 exons of the gene along with flanking splice junctions by polymerase chain reaction and DNA sequencing. Eleven nucleotide variants including two novel changes were detected. Cerebrospinal fluid (CSF) parkin protein expression of the novel mutation, Val186Ile (found in heterozygous condition in one patient only) was almost 2.7 folds lower than the controls and other PD patients. Molecular characterization of polymorphisms Ser167Asn and Val380Leu depicted that homozygous Ser167 and Val380 are significantly associated with the disease. We did not find any linkage disequilibrium among the SNPs, the low r(2) for every pair of single-nucleotide polymorphisms (SNPs) indicated that these SNPs cannot be tagged by each other. Another novel intronic change, IVS8+48C>T was present in almost equally in PD patients and controls. Among the ethnically defined Bengalee population of West Bengal, occurrence of Parkin mutation is 4% (6/150) of the PD patient pool supported with decreased folds of expression of CSF PARKIN protein. Parkin polymorphisms, Ser167 and Val380 are risk factors for the progression of the disease, and their frequency is greatly influenced by ethnic origin.

A series of M(II)Cu(II)3 stars (M = Mn, Ni, Cu, Zn) exhibiting unusual magnetic properties.

The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [M(II)(Cu(II)L)3](ClO4)2 (1, M = Mn; 2, M = Ni; 3, M = Cu; 4, M = Zn) derived from a single-compartment Schiff base ligand, N,N'-bis(salicylidene)-1,4-butanediamine (H2L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (Mn(II), Ni(II), Cu(II), or Zn(II)) is linked with two µ2-phenoxo bridges of each of the three [Cu(II)L] moieties, and thus the central metal ion is encapsulated in between three [Cu(II)L] units. The title compounds are rare or sole examples of stars having these metal-ion combinations. In the cases of 1, 3, and 4, the four metal ions form a centered isosceles triangle, while the four metal ions in 2 form a centered equilateral triangle. Both the variable-temperature magnetic susceptibility and variable-field magnetization (at 2-10 K) of 1-3 have been measured and simulated contemporaneously. While the Mn(II)Cu(II)3 compound 1 exhibits ferromagnetic interaction with J = 1.02 cm(-1), the Ni(II)Cu(II)3 compound 2 and Cu(II)Cu(II)3 compound 3 exhibit antiferromagnetic interaction with J = -3.53 and -35.5 cm(-1), respectively. Variable-temperature magnetic susceptibility data of the Zn(II)Cu(II)3 compound 4 indicate very weak antiferromagnetic interaction of -1.4 cm(-1), as expected. On the basis of known correlations, the magnetic properties of 1-3 are unusual; it seems that ferromagnetic interaction in 1 and weak/moderate antiferromagnetic interaction in 2 and 3 are possibly related to the distorted coordination environment of the peripheral copper(II) centers (intermediate between square-planar and tetrahedral). DFT calculations have been done to elucidate the magnetic properties. The DFT-computed J values are quantitatively (for 1) or qualitatively (for 2 and 3) matched well with the experimental values. Spin densities and magnetic orbitals (natural bond orbitals) correspond well with the trend of observed/computed magnetic exchange interactions.

Structures, magnetochemistry, spectroscopy, theoretical study, and catechol oxidase activity of dinuclear and dimer-of-dinuclear mixed-valence Mn(III)Mn(II) complexes derived from a macrocyclic ligand.

The work in this paper presents syntheses, characterization, magnetic properties (experimental and density functional theoretical), catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) studies of two mixed-valence dinuclear Mn(III)Mn(II) complexes, [Mn(III)Mn(II)L(µ-O2CMe)(H2O)2](ClO4)2·H2O·MeCN (1) and [Mn(III)Mn(II)L(µ-O2CPh)(MeOH)(ClO4)](ClO4) (2), and a Mn(III)Mn(II)Mn(II)Mn(III) complex, [{Mn(III)Mn(II)L(µ-O2CEt)(EtOH)}2(µ-O2CEt)](ClO4)3 (3), derived from the Robson-type macrocycle H2L, which is the [2 + 2] condensation product of 2,6-diformyl-4-methylphenol and 2,2-dimethyl-1,3-diaminopropane. In 1 and 2 and in two Mn(III)Mn(II) units in 3, the two metal centers are bridged by a bis(µ-phenoxo)-µ-carboxylate moiety. The two Mn(II) centers of the two Mn(III)Mn(II) units in 3 are bridged by a propionate moiety, and therefore this compound is a dimer of two dinuclear units. The coordination geometry of the Mn(III) and Mn(II) centers are Jahn-Teller distorted octahedral and distorted trigonal prism, respectively. Magnetic studies reveal weak ferro- or antiferromagnetic interactions between the Mn(III) and Mn(II) centers in 1 (J = +0.08 cm(-1)), 2 (J = -0.095 cm(-1)), and 3 (J1 = +0.015 cm(-1)). A weak antiferromagnetic interaction (J2 = -0.20 cm(-1)) also exists between the Mn(II) centers in 3. DFT methods properly reproduce the nature of the exchange interactions present in such systems. A magneto-structural correlation based on Mn-O bridging distances has been proposed to explain the different sign of the exchange coupling constants. Utilizing 3,5-di-tert-butyl catechol (3,5-DTBCH2) as the substrate, catecholase activity of all the three complexes has been checked in MeCN and MeOH, revealing that all three are active catalysts with Kcat values lying in the range 7.5-64.7 h(-1). Electrospray ionization mass (ESI-MS positive) spectra of the complexes 1-3 have been recorded in MeCN solutions, and the positive ions have been well characterized. ESI-MS positive spectrum of complex 1 in presence of 3,5-DTBCH2 has also been recorded, and a positive ion, [Mn(III)Mn(II)L(µ-3,5-DTBC(2-))](+), having most probably a bridging catecholate moiety has been identified.

Superparamagnetic iron oxide nanoparticle attachment on array of micro test tubes and microbeakers formed on p-type silicon substrate for biosensor applications.

A uniformly distributed array of micro test tubes and microbeakers is formed on a p-type silicon substrate with tunable cross-section and distance of separation by anodic etching of the silicon wafer in N, N-dimethylformamide and hydrofluoric acid, which essentially leads to the formation of macroporous silicon templates. A reasonable control over the dimensions of the structures could be achieved by tailoring the formation parameters, primarily the wafer resistivity. For a micro test tube, the cross-section (i.e., the pore size) as well as the distance of separation between two adjacent test tubes (i.e., inter-pore distance) is typically approximately 1 µm, whereas, for a microbeaker the pore size exceeds 1.5 µm and the inter-pore distance could be less than 100 nm. We successfully synthesized superparamagnetic iron oxide nanoparticles (SPIONs), with average particle size approximately 20 nm and attached them on the porous silicon chip surface as well as on the pore walls. Such SPION-coated arrays of micro test tubes and microbeakers are potential candidates for biosensors because of the biocompatibility of both silicon and SPIONs. As acquisition of data via microarray is an essential attribute of high throughput bio-sensing, the proposed nanostructured array may be a promising step in this direction.

Syntheses, structures, and magnetic properties of diphenoxo-bridged Cu(II)Ln(III) and Ni(II)(low-spin)Ln(III) compounds derived from a compartmental ligand (Ln = Ce-Yb).

Syntheses, characterization, and magnetic properties of a series of diphenoxo-bridged discrete dinuclear M(II)Ln(III) complexes (M = Cu or Ni, Ln = Ce-Yb) derived from the compartmental Schiff base ligand, H(2)L, obtained on condensation of 3-ethoxysalicylaldehyde with trans-1,2-diaminocyclohexane, are described. Single crystal X-ray structures of eight Cu(II)Ln(III) compounds (Ln = Ce (1), Pr (2), Nd (3), Sm (4), Tb (7), Ho (9), Er (10), and Yb (12)) and three Ni(II)Ln(III) (Ln = Ce (13), Sm (16), and Gd (18)) compounds have been determined. Considering the previously reported structure of the Cu(II)Gd(III) (6) compound (Eur. J. Inorg. Chem. 2005, 1500), a total of twelve structures are discussed/compared in this study. Four types of composition are observed in the Cu(II)Ln(III) complexes: [Cu(II)LLn(III) (NO(3))(3)(H(2)O)] (1-3: Ln = Ce-Nd), [Cu(II)LSm(III)(NO(3))(3)]·CH(3)COCH(3) (4), [Cu(II)(H(2)O)LLn(III)(NO(3))(3)] (5: Ln = Eu; 6: Ln = Gd), and [Cu(II)LLn(III)(NO(3))(3)] (4A: Ln = Sm; 7-12: Ln = Tb-Yb). On the other hand, the Ni(II)Ln(III) complexes are characterized to have two types of composition: [Ni(II)LLn(III)(H(2)O)(NO(3))(3)] (13-15: Ln = Ce-Nd) and [Ni(II)LLn(III)(NO(3))(3)]·0.5CH(3)COCH(3) (16-24: Ln = Sm-Yb). Among twelve X-ray structures, seven belong to three different isomorphous sets (Cu(II)Ce(III) (1), Cu(II)Pr(III) (2), Cu(II)Nd(III) (3), and Ni(II)Ce(III) (13); Cu(II)Tb(III) (7), Cu(II)Ho(III) (9), Cu(II)Er(III) (10), and Cu(II)Yb(III) (12); Ni(II)Sm(III) (16) and Ni(II)Gd(III) (18)), whereas space group/unit cell parameters of two others (Cu(II)Sm(III) (4) and Cu(II)Gd(III) (6)) are of different types. The lanthanide(III) centers in Cu(II)Ce(III) (1), Cu(II)Pr(III) (2), Cu(II)Nd(III) (3), and Ni(II)Ce(III) (13) complexes are eleven-coordinated, while the lanthanide(III) centers in other compounds are ten-coordinated. As evidenced from the dihedral angle (δ) between the CuO(phenoxo)(2) and LnO(phenoxo)(2) planes, variation in the extent of planarity of the bridging moiety in the Cu(II)Ln(III) compounds takes place; the ranges of δ values are 0.8-6.2° in the 4f(1-7) analogues and 17.6-19.1° in the 4f(8-13) analogues. The Cu(II)Gd(III) (6) compound exhibits ferromagnetic interaction (Eur. J. Inorg. Chem. 2005, 1500). The nature of the magnetic exchange interaction in the Cu(II)Ln(III) complexes has been understood by utilizing the empirical approach; the Ni(II)Ln(III) complexes have been used as references. The metal centers in the Eu(III) complex are uncorrelated, while other 4f(1-6) analogues (Ce(III), Pr(III), Nd(III), and Sm(III)) exhibit antiferromagnetic interaction. Among the higher analogues (4f(7-13)), only Yb(III) exhibits antiferromagnetic interaction, while interaction in other analogues (Gd(III), Tb(III), Dy(III), Ho(III), Er(III), and Tm(III)) is ferromagnetic. An important aspect of the present study is the measurement of the magnetic susceptibility of the unblocked samples as well as on blocking the samples with grease to avoid powder reorientation, if any. Comparison of the two sets of data reveals significant difference in some cases.

Age-sex variation and association of 0AB blood groups with haemoglobin level among the adult Dhimals at Naxalbari in West Bengal, India.

The Dhimals at Naxalbari of the Darjeeling district in West Bengal belong to the Indo-Mongoloid ethnic stock. Dhimal is a comparatively less known small community in North Bengal. The mean age (males = 35.93 +/- 1.14 years and females = 32.59 +/- 1.06 years) of both sexes represent the standard adult population (males = 151 and females = 171). The results show that the haemoglobin levels in both the sexes (males: 9.69 gm/dl and females: 8.82 gm/dl) among the adult Dhimals are very low. This is true in all age groups. The females are found to be more anaemic than males in all ages. Significant sex differences (p < 0.001) in this context were recorded in all ages except among the population of 60 years and above. Young adult females of reproductive ages group (20-39 years) are observed to have a less haemoglobin level (8.86 +/- 0.18 gm/dl) compared to a higher level of haemoglobin (9.29 +/- 0.30 gm/dl) found among the females of over 40 years of age. 50.88 % of the females having a mean haemoglobin level of 7.09 +/- 0.08 gm/dl and 67.56% of the males with a mean haemoglobin level of 10.75 +/- 0.08 gm/dl indicate that larger proportions of the adult Dhimal population are suffering from severe anaemia. Repeated malarial parasite infection is the major reason behind this situation. 49.70% of the total sample of both the sexes is recorded to have B blood group. 47.47% of the male and 53.45% of the female sample with blood group B along with moderately higher proportions of the AB blood group (21.78% in males and 20.22% in females) over comparatively much less frequent A and 0 blood groups in both the sexes indicate a high prevalence of B gene in the Dhimal population. The association of higher mean haemoglobin levels (10.21 +/- 0.14 gm/dl for males and 9.54 +/- 0.14 gm/dl for females) among the individuals of both the sexes with B blood groups compared to lower haemoglobin levels with other blood groups especially 0 and A indicate a selection of the B gene in the Dhimal population for survival.

Undernutrition among adult Dhimals of Naxalbari, West Bengal: comparison with other tribes of eastern India.

BACKGROUND: The tribes of India comprise approximately 8% of the total population of the country, which probably has the largest number of tribal communities in the world. In general, the tribal populations are among the most underprivileged and undernourished people in India. OBJECTIVES: To determine the anthropometric characteristics and prevalence of undernutrition, based on body mass index (BMI), of adult Dhimals, a tribal population of Naxalbari, West Bengal, India, and to compare these results with those from four other tribes of Eastern India: the Bathudis, Kora Mudis, Santals, and Savars. METHODS: A total of 305 adult (18 years or older) Dhimals (159 men and 146 women) from three villages (Maniram, Hatighisa, and Buraganj) in the Mallabari area of Naxalbari were studied. These villages are located 5 km from Siliguri town, which is approximately 580 km from Kolkata, the provincial capital of West Bengal. Anthropometric measurements included height and weight. BMI was calculated by the standard equation. Undernutrition was evaluated according to World Health Organization (WHO) cutoff points. RESULTS: The overall prevalence of undernutrition (BMI < 18.5) was very high (36.4%). The prevalence was significantly higher in women than in men (46.4% vs. 27.0%; chi2 = 12.54; p < .001; odds ratio, 2.35). According to the WHO criterion, the prevalence of undernutrition was high and the situation was serious in men. Among women, the prevalence of undernutrition was very high and the situation was critical. However, in general, compared with other tribal people of eastern India except the Santals, adult Dhimals had better anthropometric and nutritional profiles. CONCLUSIONS: This study provides evidence that although the anthropometric and nutritional profiles of adult Dhimals are better than those of some of the other tribal populations of eastern India, immediate appropriate nutritional intervention programs are needed for implementation among this ethnic group.