A dual borohydride (Li and Na borohydride) catalyst/additive together with intermetallic FeTi for the optimization of the hydrogen sorption characteristics of Mg(NH2)2/2LiH.

The present study deals with the material tailoring of Mg(NH2)2-2LiH through dual borohydrides: the reactive LiBH4 and the non-reactive NaBH4. Furthermore, a pulverizer, as well as a catalyst FeTi, has been added in order to facilitate hydrogen sorption. Addition of LiBH4 to LiNH2 in a 1 : 3 molar ratio leads to the formation of Li4(BH4)(NH2)3 which also acts as a catalyst. However, the addition of NaBH4 doesn't lead to any compound formation but shows a catalytic effect. The onset dehydrogenation temperature of thermally treated Mg(NH2)2-2LiH/(Li4(BH4)(NH2)3-NaBH4) is 142 °C as against 196 °C for the basic material Mg(NH2)2-2LiH. However, with the FeTi catalyzed Mg(NH2)2-2LiH/(Li4(BH4)(NH2)3-NaBH4, it has been reduced to 120 °C. This is better than other similar amide/hydride composites where it is 149 °C (when the basic material is catalyzed with LiBH4). The FeTi catalyzed Mg(NH2)2-2LiH/(Li4(BH4)(NH2)3-NaBH4 sample shows better de/re-hydrogenation kinetics as it desorbs 3.9 ± 0.04 wt% and absorbs nearly 4.1 ± 0.04 wt% both within 30 min at 170 °C (with the H2 pressure being 0.1 MPa for desorption and 7 MPa for absorption). The eventual hydrogen storage capacity of Mg(NH2)2-2LiH/(Li4(BH4)(NH2)3-NaBH4 together with FeTi has been found to be ∼5.0 wt%. To make the effect of catalysts intelligible, we have put forward in a schematic way the role of Li and Na borohydrides with FeTi for improving the hydrogen sorption properties of Mg(NH2)2-2LiH.

Hydrogen evolution reaction from bare and surface-functionalized few-layered MoS2 nanosheets in acidic and alkaline electrolytes.

Hydrogen is considered as an ideal and sustainable energy carrier because of its high energy density and carbon-free combustion. Electrochemical water splitting is the only solution for uninterrupted, scalable, and sustainable production of hydrogen without carbon emission. However, a large-scale hydrogen production through electrochemical water splitting depends on the availability of earth-abundant electrocatalysts and a suitable electrolyte medium. In this article, we demonstrate that hydrogen evolution reaction (HER) performance of electrocatalytic materials can be controlled by their surface functionalization and selection of a suitable electrolyte solution. Here, we report syntheses of few-layered MoS2 nanosheets, NiO nanoparticles (NPs), and multiwalled carbon nanotubes (MWCNTs) using scalable production methods from earth-abundant materials. Magnetic measurements of as-produced electrocatalyst materials demonstrate that MoS2 nanoflakes are diamagnetic, whereas surface-functionalized MoS2 and its composite with carbon nanotubes have strong ferromagnetism. The HER performance of the few-layered pristine MoS2 nanoflakes, MoS2/NiO NPs, and MoS2/NiO NPs/MWCNT nanocomposite electrocatalysts are studied in acidic and alkaline media. For bare MoS2, the values of overpotential (η10) in alkaline and acidic media are 0.45 and 0.54 V, respectively. Similarly, the values of current density at 0.5 V overpotential are 27 and 6.2 mA/cm2 in alkaline and acidic media, respectively. The surface functionalization acts adversely in the both alkaline and acidic media. MoS2 nanosheets functionalized with NiO NPs also demonstrated excellent performance for oxygen evolution reaction with anodic current of ~60 mA/cm2 and Tafel slope of 78 mVdec-1 in alkaline medium.

Recyclable Visible Light-Driven O-g-C3N4/Graphene Oxide/N-Carbon Nanotube Membrane for Efficient Removal of Organic Pollutants.

Organic pollutants are harmful to human health, which creates a global need for the development of novel and effective materials for efficiently removing contaminants. Accordingly, an efficient visible light-driven heterostructured membrane combined with oxygen-modified monolayer g-C3N4, graphene oxide, and nitrogen-doped carbon nanotubes (CNTs) (O-g-C3N4/GO/N-CNT) was successfully fabricated through electrostatic interactions and subsequent vacuum filtration. The results suggested that the O-g-C3N4/GO/N-CNT membrane exhibited higher degradation rate than those of O-g-C3N4/GO and pure O-g-C3N4 under visible light exposure. This enhanced photocatalytic performance was attributed to the introduction of GO and N-CNT, which acted as electronic acceptors for monolayer O-g-C3N4 that effectively inhibited recombination of photogenerated electron-hole pairs, thus enhancing visible light photocatalytic activity. Furthermore, the enrichment and degradation rates of O-g-C3N4/GO/N-CNT membranes were demonstrated for tetracycline hydrochloride, which were found to be 96.64 and 94.30%, respectively, and no distinct enrichment or catalytic activity reduction was observed when their reusability was measured. These results suggested that these recyclable O-g-C3N4/GO/N-CNT membranes provide a new strategy for the highly efficient removal of environmental pollutants.

Facile fabrication of ternary TiO2-gold nanoparticle-graphene oxide nanocomposites for recyclable surface enhanced Raman scattering.

A bi-functional ternary nanocomposite was developed by decorating TiO2 and gold nanoparticles on the reduced graphene oxide nanosheets (TiO2-Au-rGO) for recyclable surface enhanced Raman scattering (SERS) detection. TiO2-Au-rGO nanocomposites have been shown to demonstrate the superior SERS performances, which can be used for highly sensitive detection of rhodamine 6 G with a limit of detection of 1.2 × 10-10 M. Subsequently, the surface can be cleaned automatically by the photocatalytic degradation of the adsorbed analytes into inorganic small molecules under visible light irradiation. This can be attributed to the excellent photocatalytic degradation ability, leading to a recyclable SERS application. After being used four times, their excellent SERS and catalytic performances can still be retained. These results suggest that the TiO2-Au-rGO nanocomposites can provide a new strategy for fabricating recyclable SERS substrates, which are highly desirable for SERS practical application.

Enhanced hydrogen sorption in a Li-Mg-N-H system by the synergistic role of Li4(NH2)3BH4 and ZrFe2.

The present investigation describes the synergistic role of Li4(BH4)(NH2)3 and ZrFe2 in the hydrogen storage behaviour of a Li-Mg-N-H hydride system. The onset desorption temperature of ZrFe2-catalysed Mg(NH2)2-LiH-Li4(BH4)(NH2)3 is ∼122 °C, which is 83 °C, 63 °C, and 28 °C lower than that of thermally treated 2LiNH2-1MgH2, 2LiNH2-1MgH2-4 wt%ZrFe2, and 2LiNH2-1MgH2-0.1LiBH4 composites, respectively. Native Mg(NH2)2-LiH-Li4(BH4)(NH2)3 absorbed only 2.78 wt% of H2 within 30 min. On the other hand, the ZrFe2-catalysed Mg(NH2)2-LiH-Li4(BH4)(NH2)3 sample absorbed 3.70 wt% of hydrogen within 30 min and 5 wt% of H2 in 6 h at 180 °C and 7 MPa H2 pressure. Mg(NH2)2-LiH-Li4(BH4)(NH2)3 catalyzed with ZrFe2 shows negligible degradation of the storage capacity even after repeated cycles of de/rehydrogenation. The effect of ZrFe2 and Li4(BH4)(NH2)3 on a Mg(NH2)2/LiH composite has been described and discussed with the help of structural (X-ray diffraction), microstructural (electron microscopy), and vibrational modes of molecules through FTIR studies. The present results suggest that an optimum catalysis may originate from the synergistic action of an in situ formed quaternary hydride (Li4(BH4)(NH2)3) and an intermetallic-like ZrFe2, which acts as a pulverizer cum catalyst.

Quasicrystal as a Catalyst for the Synthesis of Carbon Nanotubes.

The present report describes the catalytic activity of mechanically activated nano quasicrystalline Al65Cu20Fe15 and related nano crystalline Al50Cu28Fe22 for the synthesis of carbon nanotubes (CNTs). CNTs are synthesized by catalytic decomposition of ethanol through nano quasicrystalline Al65Cu20Fe15 and related crystalline Al50Cu28Fe22 alloys as a catalyst. The synthesized multi-walled CNTs exhibits tube diameter ranging from 5 to 25 nm. The synthesized CNTs are characterized by scanning and transmission electron microscopy. It is found that Al65Cu20Fe15 nanoquasicystal shows better catalytic behaviour as compared to nano-crystalline Al50Cu28Fe22 alloys for decomposition of ethanol during the synthesis of multi-walled CNTs.

Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal.

The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe3O4 rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

Templated quasicrystalline molecular ordering.

Quasicrystals are materials with long-range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on 5-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently separated Fe atoms on icosahedral Al-Cu-Fe to form a unique quasicrystalline lattice, whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at 10-fold symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag-In-Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template.

Endothelial function, arterial wall mechanics and intima media thickness in juvenile idiopathic arthritis.

OBJECTIVES: Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease of children which might persist into adulthood. Systemic inflammation seen in adult RA patients has been shown to be associated with alteration in endothelial function, arterial wall mechanics and intima media thickness. Our study was planned to assess similar changes in JIA patients. METHODS: Thirty-one newly diagnosed JIA patients and a similar number of age- and sex-matched controls were enrolled in the study. Endothelial function was assessed by measuring flow mediated dilation and glyceryl trinitrate (GTN)-mediated dilation of the brachial artery. To assess arterial stiffness, various arterial wall mechanic parameters such as cross-sectional compliance, cross-sectional distensibility, shear stress and elastic modulus were derived. Intima media thickness of the common carotid artery was measured as a marker of subclinical atherosclerosis. RESULTS: The brachial artery diameter at rest was found to be slightly lower in the patients than controls (0.258 ± 0.042 vs. 0.264 ± 0.039; p=0.54). No significant difference was found in flow mediated dilation (17.71 ± 9.26 vs. 16.31 ± 8.23; p=0.53), GTN mediated dilation (25.25 ± 10.02 vs. 23.66 ± 9.79; p=0.53) or FMD: GTN mediated dilation ratio (0.730 ± 0.432 vs. 0.717 ± 0.280; p=0.89) between the cases and controls. There was also no significant difference in carotid artery intima media thickness (0.065 ± 0.0068 vs. 0.068 ± 0.007; p=0.084) between cases and controls. Cases in different subsets of JIA were also analysed separately with regards to FMD, GTN mediated dilation and cIMT but no difference was found between cases in each subset and their controls. Cross-sectional compliance was significantly lower in cases than controls (0.0016 ± 0.0005 vs. 0.002 ± 0.001; p=0.034). Cross-sectional distensibility (0.009 ± 0.003 vs. 0.011 ± 0.006; p=0.14) was also found to be lower whereas diastolic wall shear stress (299.9 ± 47.08 vs. 294.9 ± 59.5; p=0.72) and elastic modulus (1138.5 ± 1085.8 vs. 911 ± 453; p=0.19) were found to be higher in cases as compared to controls. But these differences were not statistically significant. When the subsets were analysed separately for vessel wall indices, cross-sectional compliance was found to be significantly lower in systemic arthritis patients as compared to controls. A high level of intra- and inter-observer agreement was found for all the ultrasonographically evaluated parameters. CONCLUSIONS: Arterial wall indices were found altered in JIA patients indicating increased arterial stiffness. Larger studies are required to assess endothelial dysfunction, intima media thickness and arterial stiffness in each subset of JIA patients.

Scanning tunneling microscopy of a polygrain Al­Pd­Re quasicrystal: study of the relative surface stability.

Scanning tunneling microscopy and x-ray photoemission spectroscopy on a polygrain icosahedral (i-) Al­Pd­Re quasicrystal (QC) show the formation of the twofold surfaces with symmetry and composition expected from the bulk. The predominant occurrence of the twofold surface on the polygrain i-QC having random grain orientation, as well as preferential formation of terrace edges, kinks and voids along the twofold axes, consistently indicates that the twofold surface, which has the highest atomic density, is the most stable among all the crystallographic planes.

Isolated tuberculous liver abscess in a 3-year-old immunocompetent child.

Tuberculous liver abscess without active pulmonary or miliary tuberculosis or other clinical evidence of tuberculosis, is very rare. A 3-year-old immunocompetent boy with isolated tuberculous liver abscess recovered completely on systemic anti-tuberculous drugs.

A study of school adjustment, self-concept, self-esteem, general wellbeing and parent child relationship in Juvenile Idiopathic Arthritis.

OBJECTIVE: To assess school adjustment, self-concept, self-esteem, general wellbeing and parent-child relationship in children with Juvenile Idiopathic Arthritis (JIA)and to study the correlation of these parameters with chronicity of disease, number of active joints, laboratory parameters of disease activity and JIA subtypes. METHODS: A total of 64 children (32 cases and 32 controls) were recruited for analysis. Self report questionnaires which included PGI General Wellbeing Measure, Adjustment Inventory for School Students, Parent Child Relationship Scale, Self Esteem Inventory and Self Concept Questionnaires were used to assess all the enrolled subjects. RESULTS: Cases had significantly lower general physical well being (p < 0.001), self- esteem (p = 0.039), social self-concept (p = 0.023) and poorer social (p = 0.002), educational (p = 0.002) and overall (p = 0.006) adjustment as compared to controls. Both parents of cases were significantly more demanding (p = 0.028, p = 0.004)and mothers were over protective (p = 0.009) and pampering with object rewards (p = 0.02). PGI wellbeing score (p = 0.042, p = 0.019) and self concept (p = 0.002, for social SCQ p = 0.030) correlated well with number of active joints and ESR. As the disease duration increased, fathers tended to neglect their children (p = 0.043) and with persistent disease activity (reflected by CRP positivity) even resorted to punishment (p = 0.022) or remained indifferent (p = 0.048). CONCLUSIONS: JIA significantly hampers the child's self-esteem, self-concept, adjustment in school, general wellbeing and evokes disturbed parent-child relationship.

Transfusion related acute lung injury with intravenous immunoglobulin.

This case report describes transfusion related acute lung injury with the use of intravenous immunoglobulin in a child with Guillain barre syndrome.

Formation of nano-quasicrystalline decagonal phase in the Al70Cu10Co5Ni15 system by high energy ball milling.

A nano decagonal quasicrystalline phase in the Al70Cu10Co5Ni15 alloy has been synthesized by mechanical alloying of a mixture of elemental powders followed by annealing. A high-energy ball milling of the elemental mixture of Al, Cu, Co and Ni leads to the formation of B2 type quaternary intermetallic alloys. The X-ray diffraction and transmission electron microscopy techniques have been employed for characterization of the samples. It was observed that the dissolution of the individual elements into an alloy led to the formation of a nano B2 phase. This phase was found to be quite stable against milling and no other crystalline or amorphous phases could be detected. Milled powder after annealing at 700 degrees C for 60 h was found to transform to nano-decagonal phase. Attempts have been made to understand the evolution of the complex intermetallic nano phases and their relative stability during milling.

Synthesis of nanocrystalline (Co, Ni)Al2O4 spinel powder by mechanical milling of quasicrystalline materials.

In the present study, attempts have been made to synthesize the nano-crystalline (Co, Ni)Al2O4 spinel powders by ball milling and subsequent annealing. An alloy of Al70Co15Ni15, exhibiting the formation of a complex intermetallic compound known as decagonal quasicrystal is selected as the starting material for mechanical milling. It is interesting to note that this alloy is close to the stoichiometry of aluminum and transition metal atoms required to form the aluminate spinel. The milling was carried out in an attritor mill at 400 rpm for 40 hours with ball to powder ratio of 20 : 1 in hexane medium. Subsequent to this annealing was performed in an air ambience for 10, 20, and 40 h at 600 degrees C in side the furnace in order to oxidize the decagonal phase and finally to form the spinel structure. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of nano-sized decagonal phase after milling and then (Co, Ni)Al2O4 spinel type phase after annealing. The XRD studies reveal the lattice parameter to be 8.075 angstroms and the lattice strain as 0.6%. The XRD and TEM explorations of spinel phase indicate the average grain size to be approximately 40 nm.

Infection-associated haemophagocytosis: the tropical spectrum.

Reactive proliferation and inappropriate activation of mature histiocytes with haemophagocytosis (HP) may occur in association with a wide variety of infections, neoplasms, collagen vascular diseases, and acquired and inherited immunodeficiency states. The association with infections is particularly important because overwhelming HP can obscure the typical clinical features of the primary disease and negatively affects outcome. A high index of suspicion is required for early recognition of associated HP as the cause of cytopenias. Institution of specific therapy is crucial for survival. This study highlights the wide spectrum of tropical diseases that can have associated reactive HP. Thirty cases with documented prominent HP on bone marrow aspiration smears were reviewed. Twenty-one (69%) of the marrows were from patients who had common tropical infections: malaria, typhoid and visceral leishmaniasis and 11 of 15 patients (73%) who were followed up improved on specific infection-directed and supportive measures. The presence of severe HP in bone marrow smears correlated with marked cytopenias. Recognition of HP in this geographical region should stimulate the search for one of these infections as early institution of specific therapy is crucial for patient survival.

Erythromycin in pityriasis rosea: A double-blind, placebo-controlled clinical trial.

BACKGROUND: The study stemmed from an incidental observation of improvement in 2 patients with pityriasis rosea while receiving erythromycin. OBJECTIVE: The purpose of the study was to evaluate the efficacy of erythromycin in patients with pityriasis rosea. METHODS: A double-blind, placebo-controlled clinical study was performed in an outpatient setting in a major hospital. Ninety patients over a period of 2 years were alternatively assigned to treatment group or placebo group. Patients in the treatment group received erythromycin in divided doses for 14 days. The response was categorized as complete response, partial response, or no response. All patients were followed up for 6 weeks. RESULTS: Both groups were comparable with regard to age at presentation, sex, and average duration of disease at the time of reporting to the clinic. Upper respiratory tract infection before the appearance of skin lesions was reported in 68.8% of all patients. Complete response was observed in 33 patients (73.33%) in the treatment group and none in the placebo group (P <.0001). CONCLUSION: Oral erythromycin was effective in treating patients with pityriasis rosea.