A rationale for the rapid extraction of ultra-low-level uranyl ions in simulated bioassays regulated by Mn-dopants over magnetic nanoparticles.

Although the sorption of uranyl ions and other heavy metal ions over magnetic nanoparticles is well reported, the parameters governing the sorption process over the magnetic nanoparticles have not been clearly enumerated. However, to increase the efficiency of the sorption over the surface of these magnetic nanoparticles, it is essential to understand the different structural parameters that are involved in the sorption process. The sorption of uranyl ions and other competitive ions in simulated urine samples at different pH was effectively accomplished over magnetic nanoparticles of Fe3O4 (MNPs) and Mn-doped Fe3O4 (Mn-MNPs). The MNPs and Mn-MNPs were synthesized using an easily modified co-precipitation method and were thoroughly characterised using several techniques, such as XRD, HRTEM, SEM, zeta potential, and XPS. The substitutional doping of Mn (1 to 5 at%) in the Fe3O4 lattice (Mn-MNPs) showed better sorption ability as compared to that of MNPs. The sorption properties of these nanoparticles were mainly correlated with the different structural parameters to understand the roles of surface charge and different morphological parameters. The interaction centres over the surface of MNPs with the uranyl ions were designated and the effects of ionic interactions with uranyl ions for these sites were calculated. Extensive XPS, ab initio calculations and zeta potential studies have provided deep insights into the different aspects that play key roles in the sorption process. These materials showed one of the best Kd values (∼3 × 106 cm3) in a neutral medium with very low t1/2 values (∼0.9 min). The fast sorption kinetics (very low t1/2) makes them amongst the best sorption materials for uranyl ions and optimal for the quantification of ultra-low-level uranyl ions in simulated bioassays.

Label-Free Biomolecule Detection in Physiological Solutions With Enhanced Sensitivity Using Graphene Nanogrids FET Biosensor.

Recently, graphene nanogrid sensor has been reported to be capable of sub-femtomolar sensing of Hepatitis B (Hep-B) surface antigen in buffer. However, for such low concentration of Hep-B in serum, it has been observed during real-time operation that there is an overlap of around 50% in the drain-source current sensitivity values between different concentrations of the target biomolecule, in the range from 0.1 to 100 fM. This has been attributed to the fact that the concentration of non-specific antigen in serum being significantly higher than that of the target antigen, there is a considerable deviation in the number of captured target antigen for the same concentration. Further, this degree of overlap varies from one set to another set of sensor, depending on the statistical variations in the sensor fabrication process. This phenomenon challenges the quantification of target antigen for ultralow limit in physiological analyte. In this paper, we introduce probabilistic neural network (PNN) for quantification of Hep-B down to 0.1 fM in serum using graphene nanogrids field-effect transistor biosensor. The sensor has been operated in heterodyne mode in the frequency range of 100 kHz to 1 MHz applied between drain and source to overcome the problem of Debye screening effect. The application of PNN limits the quantification error within 10% in the range of 0.1 to 100 fM in contrast to 77% and 66% using polynomial fit and static neural network models, respectively. Further, the proposed methodology lowers the detection limit of Hep-B in serum by more than three orders of magnitude compared with the state-of-the-art, real-time, label-free sensors.

Insight into growth of Au-Pt bimetallic nanoparticles: an in situ XAS study.

Au-Pt bimetallic nanoparticles have been synthesized through a one-pot synthesis route from their respective chloride precursors using block copolymer as a stabilizer. Growth of the nanoparticles has been studied by simultaneous in situ measurement of X-ray absorption spectroscopy (XAS) and UV-Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at Indus-2 SRS at RRCAT, Indore, India. In situ XAS spectra, comprising both X-ray near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) parts, have been measured simultaneously at the Au and Pt L3-edges. While the XANES spectra of the precursors provide real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed in the intermediate stages of growth. This insight into the formation process throws light on how the difference in the reduction potential of the two precursors could be used to obtain the core-shell-type configuration of a bimetallic alloy in a one-pot synthesis method. The core-shell-type structure of the nanoparticles has also been confirmed by ex situ energy-dispersive spectroscopy line-scan and X-ray photoelectron spectroscopy measurements with in situ ion etching on fully formed nanoparticles.

Oil exploration activities: assessment of hazardous impacts on 'Golden silk' cultivation.

Aliphatic-aromatic hydrocarbons and heavy metals (Cd, Cu, Co, Cr, Ni, Pb and Zn) were estimated in soil and leaf samples of Machilus bombycina (host plant of Antheraea assama silkworm) plantation along with atmospheric benzene, toluene and xylene (BTX) concentration near the oil exploration region of upper Assam, India, during the pre-monsoon and post-monsoon periods in six different sites. The results revealed higher aliphatic-aromatic hydrocarbons (ranging from 26.55 to 59.42 mg kg-1) and heavy metal contaminations in all the six soil sampling sites during the pre-monsoon period while the trend was the opposite for the plant leaves. Polyaromatic hydrocarbons (9.85 mg kg-1) were found in one soil sampling site near an abandoned oil well. The lead concentration in the soil showed values from 14.36 ± 1.5 to 96.5 ± 5.6 mg kg-1 and found to be higher than the WHO limit in most of the samples. The aliphatic-aromatic hydrocarbon m-xylene was also found in M. bombycina plant leaves which could be traced due to crude oil. Cd and Pb concentrations in leave samples were found to be higher than the maximum allowable limit of 0.3 and 5.3 mg kg-1, respectively. Principal component analysis of hydrocarbons in soil and leaves showed different clusters during the pre-monsoon and post-monsoon periods. The crude protein and total carbohydrate contents in the leaves were lower than those of uncontaminated samples which are an indication of a major disturbance to overall growth of plants. BTX concentration was found in the range of 119-198 µg m-3 which indicates that atmospheric contamination in the studied area is causing the death of A. assama larvae.

Using coal fly ash as a support for Mn(II), Co(II) and Ni(II) and utilizing the materials as novel oxidation catalysts for 4-chlorophenol mineralization.

In this work, Mn(II), Co(II) and Ni(II) were incorporated into waste coal fly ash used as a catalyst support by refluxing with the appropriate aqueous salt solution. The materials were calcined at 773-873 K for 5 h and the amount of divalent cations entering into the fly ash was determined by AAS measurements. Further characterization included estimation of oxides by XRF, structural properties by XRD, topographical features by SEM, surface functional groups by FT-IR, surface area and pore dimensions by BET N2-adsorption isotherms. The efficiency of the materials as environmental oxidation catalysts were tested with respect to destruction of 4-chlorophenol (4-CP) in water in the presence of hydrogen peroxide. Considered as one of the most persistent, toxic and largely applied organic compound, 4-CP enters water from the effluents of petrochemical, plastic, pesticide, kraft mill and other organochemical industries and research centers. Wet oxidation of 4-CP was tested by varying the mole ratio of 4-CP and H2O2, catalyst load, temperature, reaction time, 4-CP concentration and pH. Oxidation of 4-CP (5 × 10(-3) M or 643 mg L(-1)) was 51.1% for Mn(II)-fly ash, 58.3% for Co(II)-fly ash and 61.0% for Ni(II)-fly ash after 180 min at 323 K with 4-CP: H2O2 mole ratio of 1:1. COD load of the reaction mixture (4-CP: 5 × 10(-3) M, H2O2: 5 × 10(-3) M, catalyst load: 1.0 g L(-1), temperature 323 K, reaction time 0-240 min) decreased from 1480 to 620, 380, and 140 mg L(-1) respectively after oxidation with Mn(II)-fly ash, Co(II)-fly ash and Ni(II)-fly ash (overall COD reduction was 58.0, 74.3 and 90.5% respectively). The oxidation followed second order kinetics with the average rate coefficient of 7.9, 1.3 and 1.2 L mol(-1) min(-1) for Mn(II)-, Co(II)- and Ni(II)-fly ash. Increase in H2O2: 4-CP mole ratio from 1:1 to 20:1 (reaction time 300 min, catalyst load 1.0 g L(-1)) enhanced destruction from 52.1 to 95.6% for Mn(II)-fly ash, 58.3-95.6% for Co(II)-fly ash and from 60.4 to 94.8% for Ni(II)-fly ash. The oxidation increased with catalyst load but very high loads were not effective. Low pH favored the oxidation, but the catalysts performed well at the pH of aqueous 4-CP solution. A mechanism for the reactions is suggested based on the analysis of the products of oxidation.

Arsenic-tolerant, arsenite-oxidising bacterial strains in the contaminated soils of West Bengal, India.

As biological agents represent an affordable alternative to costly metal decontamination technologies, we isolated arsenic (As) oxidising bacteria from the As-contaminated soils of West Bengal, India. These strains were closely related to various species of Bacillus and Geobacillus based on their 16S rRNA gene sequences. They were found to be hyper-resistant to both As(V) (167-400 mM) and As(III) (16-47 mM). Elevated rates of As(III) oxidation (278-1250 µM h(-1)) and arsenite oxidase activity (2.1-12.5 nM min(-1) mg(-1) protein) were observed in these isolates. Screening identified four strains as superior As-oxidisers. Among them, AMO-10 completely (100%) oxidised 30 mM of As(III) within 24 h. The presence of the aoxB gene was confirmed in the screened isolates. Phylogenetic tree construction based on the aoxB sequence revealed that two strains, AGO-S5 and AGH-02, clustered with Achromobacter and Variovorax, whereas the other two (AMO-10 and ADP-25) remained unclustered. The increased rate of As(III) oxidation by these native strains might be exploited for the remediation of As in contaminated environments. Notably, this study presents the first correlation regarding the presence of the aoxB gene and As(III) oxidation ability in Geobacillus stearothermophilus.

Sm(2-x)Dy(x)Zr2O7 pyrochlores: probing order-disorder dynamics and multifunctionality.

The present work involves the synthesis of a series of Sm(2-x)Dy(x)Zr(2)O(7) compounds (0.0 ≤ x ≤ 2.0) by a controlled gel combustion process. The powders were thoroughly analyzed by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, and diffuse-reflectance UV-visible spectroscopy. The powder XRD studies revealed the system to be single-phasic throughout with retention of pyrochlore-type ordering until 40 mol % of Dy(3+), beyond which the pyrochlore lattice gives way to the defect fluorite structure. Interestingly, Raman spectroscopic studies (as against XRD studies) showed retention of pyrochlore-type ordering throughout the homogeneity range of the compositions studied. This is perhaps the first study that reports retention of a weak pyrochlore-type superstructure in the Dy(2)Zr(2)O(7) system, which was otherwise known to crystallize in the defect fluorite system. The ionic conductivity measurements showed an increase in the activation energy (E(a)) with an increase in the mole percent of Dy(3+) owing to the decreased mobility with an increase in the degree of disorder. The system possesses a tunable band gap with varying amounts of Dy(3+). First-principles calculations were performed to support a decrease in the band gap of the doped system with an increase in the Dy(3+) content. The potential as photocatalysts of some of these compositions was explored, and they exhibited high photocatalytic activity for degradation of xylenol orange, with t(1/2) increasing from pure Sm(2)Zr(2)O(7) to pure Dy(2)Zr(2)O(7).

International study on the psychometric attributes of the non-motor symptoms scale in Parkinson disease.

BACKGROUND: Nonmotor symptoms (NMS) have a great impact on patients with Parkinson disease (PD). The Non-Motor Symptoms Scale (NMSS) is an instrument specifically designed for the comprehensive assessment of NMS in patients with PD. NMSS psychometric properties have been tested in this study. METHODS: Data were collected in 12 centers across 10 countries in America, Asia, and Europe. In addition to the NMSS, the following measures were applied: Scales for Outcomes in Parkinson's Disease (SCOPA)-Motor, SCOPA-Psychiatric Complications (SCOPA-PC), SCOPA-Cognition, Hoehn and Yahr Staging (HY), Clinical Impression of Severity Index for Parkinson's Disease (CISI-PD), SCOPA-Autonomic, Parkinson's Disease Sleep Scale (PDSS), Parkinson's Disease Questionnaire-39 items (PDQ-39), and EuroQol-5 dimensions (EQ-5D). NMSS acceptability, reliability, validity, and precision were analyzed. RESULTS: Four hundred eleven patients with PD, 61.3% men, were recruited. The mean age was 64.5 +/- 9.9 years, and mean disease duration was 8.1 +/- 5.7 years. The NMSS score was 57.1 +/- 44.0 points. The scale was free of floor or ceiling effects. For domains, the Cronbach alpha coefficient ranged from 0.44 to 0.85. The intraclass correlation coefficient (0.90 for the total score, 0.67-0.91 for domains) and Lin concordance coefficient (0.88) suggested satisfactory reproducibility. The NMSS total score correlated significantly with SCOPA-Autonomic, PDQ-39, and EQ-5D (r(S) = 0.57-0.70). Association was close between NMSS domains and the corresponding SCOPA-Autonomic domains (r(S) = 0.51-0.65) and also with scales measuring related constructs (PDSS, SCOPA-PC) (all p < 0.0001). The NMSS total score was higher for women (p < 0.02) and for increasing disease duration, HY, and CISI-PD severity level (p < 0.001). The SEM was 13.91 for total score and 1.71 to 4.73 for domains. CONCLUSION: The Non-Motor Symptoms Scale is an acceptable, reproducible, valid, and precise assessment instrument for nonmotor symptoms in Parkinson disease.

Mechanistic insight by in situ FTIR for the gas phase photo-oxidation of ethylene by V-doped titania and nano titania.

Vanadium-doped titania is found to be a better photocatalyst for gas phase photo-oxidation of ethylene than nano titania. In situ FTIR studies were undertaken to elucidate the mechanistic pathway for ethylene oxidation on these two catalyst surfaces. Vanadium doping leads to formation of more chemisorbed hydroxyl species, which makes it a better photocatalyst. The labile hydroxyls which were responsible for the reduction of V(5+) to V(4+) during the process of calcination were also ascertained. The ethylene decomposition occurs via formation of ethoxy groups, transformed to acetaldehyde or enolates, subsequently to acetates/formates, and then to CO(2). The enolates were more stabilized on the TiO(2) surface, leading to formation of formates along with the acetates. On vanadium-doped TiO(2), acetaldehyde was more stabilized than its enol tautomer, leading to the formation of labile acetic acid and acetates. The formation of the labile acetic acid, adsorbed acetates, and the adsorbed acetate -M salts led to easier oxidation of them to provide higher yield of CO(2). The higher positive charge density over Ti in Ti(0.95)V(0.05)O(2) with respect to nano TiO(2) makes the acetate (stronger nucleophile) a more stable intermediate on it.

Syndromic approach for determination of reproductive tract infections among adolescent girls.

The present study shows overall prevalence (64%) of reproductive tract infection among adolescent girls, based on self-perceived symptoms. Mean age of respondents were found to be 17.8 +/- 0.82 years and mean age at marriage and mean age at first pregnancy were 17.2 years and 17.5 years respectively; 35.35% of girls in the present study were married. In addition, no significant difference was observed between unmarried (60.10%) and married (71.17%) reproductive tract infection groups. Moreover, no significant association was present in prevalence of reproductive tract infection between the Muslim (67%) and the Hindu (60%). Highest prevalence (84.06%) of reproductive tract infection was observed among illiterate girls and with improvement of educational status there was decrease in the prevalence and the association was found highly significant. Significantly, higher prevalence (72%) was observed among members of family size 7 and above.

Vapor-phase photo-oxidation of methanol over nano-size titanium dioxide clusters dispersed in MCM-41 host material part 2: catalytic properties and surface transient species.

We report in this paper on the ultraviolet-assisted vapor-phase oxidation of methanol at room temperature, with the help of nano-size clusters of titanium dioxide dispersed in an MCM-41 silicate matrix. The surface species formed during the adsorption/oxidation of methanol and the transformation that they undergo as a result of ultraviolet irradiation were monitored using in-situ Fourier transform infrared and thermal desorption spectroscopy techniques. Parallel experiments conducted on TiO2/MCM, bulk titania, and pristine MCM-41 samples helped in identifying the individual role of titanium dioxide and host matrix in these processes. The photo-catalytic oxidation of methanol, at concentrations of 0.1 to 1.1 mol% in air, gave rise to formation of CO2 and H2O as products, for both the TiO2/MCM and bulk TiO2 samples. No such reaction occurred on titania-free MCM. Furthermore, the rate of reaction depended upon the TiO2 content of a sample and also on the concentration of methanol in reaction mixture. Thus, the rate of conversion increased progressively with the increase in TiO2 loading from 5 to 21 wt% in TiO2/MCM samples, particularly for the experiments with high concentration of methanol. For low methanol concentration (0.1 mol%) in air, the effect of titania content in MCM was very small. The specific activity (per g of titania) of a sample, on the other hand, showed an inverse relationship with the loading of titanium dioxide in a sample. Infrared and temperature-programmed desorption results revealed that the mode of CH3OH adsorption and the reactivity of the transient species formed during the oxidation process were independent of the size of dispersed titania particles. Thus, the particles of approximately 2-6 nm size, present in TiO2/MCM, exhibited a chemisorption behavior similar to that of the bulk titania. The results of the present study provide strong evidence that the hydroxyl groups, both on the host matrix and at the titania sites, participate independently in the formation of methoxyl groups and at the same time promote the heterogeneous photo-catalytic oxidation of methanol molecules via formation of transient formate groups. Our results also show that the effect of titania crystallite size in the photo-catalytic properties relate mainly to the larger surface area and hence to the enhanced number of chemisorption sites, rather than to the changes in electronic properties.

Bobble-head doll syndrome: some atypical features with a new lesion and review of the literature.

Bobble-head doll syndrome is a rare and unique movement disorder encountered in children. It is characterized by continuous or episodic involuntary forward and backward and side to side movement of the head at the frequency of 2-3 Hz. Neuroimaging in most of the cases reveals third ventricular tumors, suprasellar arachnoid cysts, aqueductal stenosis and other lesions in the region of the third ventricle along with communicating hydrocephalus. In most of the circumstances, the problem starts in the first decade of life and diversion of cerebrospinal fluid by shunt operation is very often accompanied by dramatic improvement. We report one case where bobbing of the head started at around 12 years of age. Additionally, there was evidence of partial left abducens nerve palsy, tremor in the outstretched hands, difficulty in finger-nose test and tandem walking, hyperreflexia and extensor plantar response. He was unconscious on two occasions and there was evidence of gross hydrocephalus along with a thin membranous web, running transversely across the lower part of the aqueduct of Sylvius without any cerebrospinal fluid flow void. Ventriculo-peritoneal shunt abolished the abnormal movements. We propose that the aqueductal web was the offending agent for the pathogenesis of bobble-head doll syndrome in our case and this lesion has not been identified in the cases reported so far. Relevant literature in this regard has also been reviewed.

Orthostatic tremor: report of a case and review of the literature.

Orthostatic tremor is a rare movement disorder characterized by tremulousness of the lower limbs on standing that disappears on walking, sitting or on lying down and a distinctive electromyographic burst of 14 to 16 Hz. On inspection, fine ripples can sometimes be seen over the quadriceps on standing. The tremor has a tendency to reappear even in the supine posture if the lower limb muscles are put to an isometric contraction state, indicating thereby that in spite of the fact that the tremor occurs on standing, it is essentially 'orthostasis independent' and the central factor is the contraction of the muscles. As a matter of fact, the tremor is abolished if the subject is suspended by harness, thus relieving him of muscle contraction. Doubts are being cast whether it is a variant of essential tremor since a number of families are being reported to be suffering from this disease as well. Positron emission tomography reveals hyperactivity of cerebellum in orthostatic tremor as it shows in essential tremor, therefore lending credence to such a hypothesis. However, lack of response to alcohol, propranolol and primidone in orthostatic tremor stands out as a serious challenge to such a view. Lack of positive family history, synchrony of contracting group of muscles and negative 'resetting' of the tremor by increasing peripheral load-phenomena consistently observed in orthostatic tremor and not in essential tremor, are other features that often help to distinguish between the two conditions. We report a case of orthostatic tremor that presented with the classical clinical and electromyographic features. Relevant literature in this regard is also being reviewed.

(24R)-24,25-Dihydroxycycloartan-3-one.

In the title compound, C(30)H(50)O(3), the three six-membered rings adopt chair, twist and twist-boat conformations. The five-membered ring is in a slightly distorted envelope conformation. The substituent on the five-membered ring is in an extended conformation, with its two hydroxyl O atoms forming an intramolecular hydrogen bond. One of these O atoms also forms an intermolecular hydrogen bond with the oxygen of the carbonyl group in a neighbouring molecule.

Sporadic paroxysmal exercise induced dystonia: report of a case and review of the literature.

Sporadic paroxysmal exercise induced dystonia (PEID) is a rare condition. So far only fifteen cases have been reported in the world literature. It is characterised by dystonic posture on prolonged exercise, which gets relieved with rest. In general, these are refractory to medical treatment. We report one such case, along with review of the literature. The lower limbs were spared and only right shoulder was tucked up with the head turning to right side. The duration of exercise necessary to bring out the dystonic posture gradually diminished with time, a feature not reported previously.

Snake venom hemorrhagins.

Viperine and crotaline snake venoms contain one or more hemorrhagic principles called hemorrhagins. These are zinc-containing metalloproteases characterized by the presence of a protease domain, with additional domains in some of them. They act essentially by degrading the component proteins of basement membrane underlying capillary endothelial cells. The toxins also act on these cells causing lysis or drifting apart, resulting in hemorrhage per rhexis or per diapedesis. Some of these toxins have been found to exert additional effects such as fibrinogenolysis and platelet aggregation that facilitate hemorrhage. The structural and functional features of this class of toxins have been discussed in this review in an attempt to get a better understanding of their toxicity. This can be of immense therapeutic value in the management of snake venom poisoning, as hemorrhagins are among the major lethal factors in snake venom.