A first-principles study of helium storage in oxides and at oxide--iron interfaces

Density-functional theory calculations based on conventional as well as hybrid exchange-correlation functionals have been carried out to study the properties of helium in various oxides (Al2O3, TiO2, Y2O3, YAP, YAG, YAM, MgO, CaO, BaO, SrO) as well as at oxide-iron interfaces. Helium interstitials in bulk oxides are shown to be energetically more favorable than substitutional helium, yet helium binds to existing vacancies. The solubility of He in oxides is systematically higher than in iron and scales with the free volume at the interstitial site nearly independently of the chemical composition of the oxide. In most oxides He migration is significantly slower and He--He binding is much weaker than in iron. To quantify the solubility of helium at oxide-iron interfaces two prototypical systems are considered (Fe|MgO, Fe|FeO|MgO). In both cases the He solubility is markedly enhanced in the interface compared to either of the bulk phases. The results of the calculations allow to construct a schematic energy landscape for He interstitials in iron. The implications of these results are discussed in the context of helium sequestration in oxide dispersion strengthened steels, including the effects of interfaces and lattice strain.Comment: 13 pages, 10 figures, 4 table

Mechanical Behavior of Nanostructured Hybrids Based on Poly(Vinyl Alcohol)/Bioactive Glass Reinforced with Functionalized Carbon Nanotubes

This study reports the synthesis and characterization of novel tridimensional porous hybrids based on PVA combined with bioactive glass and reinforced by chemically functionalized carbon nanotubes (CNT) for potential use in bone tissue engineering. The functionalization of CNT was performed by introducing carboxylic groups in multiwall nanotubes. This process aimed at enhancing the affinity of CNTs with the water-soluble PVA polymer derived by the hydrogen bonds formed among alcohol (PVA) and carboxylic groups (CNT–COOH). In the sequence, the CNT–COOH (0.25 wt%) were used as the nanostructure modifier for the hybrid system based on PVA associated with the bioactive glass (BaG). The mechanical properties of the nanostructured hybrids reinforced with CNT–COOH were evaluated by axial compression tests, and they were compared to reference hybrid. The averaged yield stresses of macroporous hybrids were (2.3 ± 0.9) and (4.4 ± 1.0) MPa for the reference and the CNT reinforced materials, respectively. Moreover, yield strain and Young's modulus were significantly enhanced by about 30% for the CNT–COOH hybrids. Hence, as far as the mechanical properties are concerned, the results have clearly showed the feasibility of utilizing these new hybrids reinforced with functionalized CNT in repairing cancellous bone tissues

Pengembangan Formula Minuman Olahraga Berbasis Tempe untuk Pemulihan Kerusakan Otot

Penelitian ini bertujuan untuk mempelajari formulasi minuman olahraga berbasis tempe untuk pemulihan kerusakan otot dengan kandungan gizi yang tepat dan dapat diterima secara sensori. Penelitian ini menggunakan rancangan acak lengkap dengan faktor tunggal yaitu jumlah penambahan air untuk melarutkan tepung tempe yang terdiri dari tiga tingkatan yaitu 500 ml, 600 ml dan 700 ml, dengan masing-masing perlakuan mengandung 23 gram protein. Tepung tempe yang digunakan mengandung kadar air 5,39%, abu 1,22 % berat kering, protein 45,55% berat kering, lemak 33,9% berat kering, karbohidrat 13,94 % berat kering, kalsium 0,14% berat kering, besi 0,018% berat kering, natrium 0,004% berat kering, magnesium 0,06% berat kering, klorida 0,04% berat kering dan kalium 0,10% berat kering. Hasil uji hedonik minuman tempe menunjukkan bahwa penambahan air 600 ml cenderung mempunyai nilai kesukaan secara keseluruhan yang paling tinggi (5,42) dibandingkan dengan penambahan air 700 ml (5,37) dan 500 ml (nilai 4,92) (P>0,05). Minuman tempe dengan penggunaan air 600 ml mempunyai penerimaan secara keseluruhan yang tertinggi dengan nilai 80%. Minuman tersebut mempunyai karakteristik per sajian sebagai berikut kandungan protein 23 gram, karbohidrat 48 gram, lemak 17,11 gram, energi 438 kkal, branched chain amino acids (BCAA) 4161,6 mg, Ca 72,92 mg, Fe 9,46 mg, Mg 33,12 mg, Na 2,37 mg dan Cl 21,30 mg, dan K 54 mg

A Closer Look at Solar Wind Sputtering of Lunar Surface Materials

Solar-wind induced potential sputtering of the lunar surface may be a more efficient erosive mechanism than the "standard" kinetic (or physical) sputtering. This is partly based on new but limited laboratory measurements which show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. The enhancements seen in the laboratory can be orders of magnitude for some surfaces and highly charged incident ions, but seem to depend very sensitively on the properties of the impacted surface in addition to the fluence, energy and charge of the impacting ion. For oxides, potential sputtering yields are markedly enhanced and sputtered species, especially hydrogen and light ions, show marked dependence on both charge and dose

Prevalence and determinants of glucose intolerance among HIV/AIDS patients in north-central Nigeria

Background: The advent of potent antiviral drugs has revolutionalised the clinical course of HIV / AIDS resulting in increased survival and improved quality of life. Metabolic derangements in HIV infected patients are becoming more common probably due to this increased survival from the use of HAART. There is limited data on the occurrence of glucose intolerance among HIV patients in Nigeria.Objective: To determine the prevalence of glucose intolerance and associated risk factors in HIV/AIDS patients.Methods: Consenting adult HIV patients at the HIV clinic of the Jos University Teaching Hospital (JUTH), Jos , Nigeria were evaluated were evaluated for the presence of glucose intolerance using a 75g oral glucose tolerance test (OGTT). There clinical characteristics, anthropometry, CD4 cell counts and viral load were determined using appropriate standard techniques. Impaired Fasting Glucose (IFG), Impaired Glucose Tolerance (IGT), and Diabetes Mellitus (DM) were defined based on the American Diabetes Association (ADA) cut-off values.Results: Of the 584 patients studied, 384 (130 males and 251 females) with mean±SD age of 38±15 years were HAARTtreated; while 200 (61 males and 139 females) with mean±SD age of 33±17 years were HAART-naive. Overall, the prevalence of GI was 40.4% (IFG) 19.5%, IGT 11.5% and DM 9.4%. The prevalence of IFG (27.1%) and DM (11.2%) in HAART - treated patients were observed and those in HAART-naive patients were (IFG 5.0%,DM 6.0%), p<0.005. IGT was more prevalent in HAART-naive than in HAART-treated patients (19.5%, and 7.3% respectively), p<0.05. The proportions of patients with GI were higher in overweight and obese HAART-treated patients with moderate CD4 cell count (200-500 x106 cell/L); while in the HAART-naive patients, GI was more prevalent in underweight subjects with CD4 cell count (<200 x 106 cell/L). The Determinants of GI were age, increasing BMI, low CD4 cell count, metabolic syndrome and HAART treatment duration. The independent predictors of glucose intolerance in HIV / AIDS patients were low CD4 cell count and prolonged HAART treatment duration.Conclusion: The prevalence of GI among HIV/AIDS patients in North-Central Nigeria is high. Treatment with HAART and low CD4 cell count are strong determinants of glucose intolerance in our HIV / AIDS patients. Regular screening for glucose intolerance among our HIV / AIDS patients is recommended.Keywords: HIV, Glucose Intolerance, Prevalence, North-Central Nigeri

Functionalized chitosan derivatives as nonviral vectors: Physicochemical properties of acylated N,N,N-trimethyl chitosan/oligonucleotide nanopolyplexes

Cationic polymers have recently attracted attention due to their proven potential for nonviral gene delivery. In this study, we report novel biocompatible nanocomplexes produced using chemically functionalized N,N,N-trimethyl chitosan (TMC) with different N-acyl chain lengths (C 5 -C 18 ) associated with single-stranded oligonucleotides. The TMC derivatives were synthesized by covalent coupling reactions of quaternized chitosan with n-pentanoic (C 5 ), n-decanoic (C 10 ), and n-octadecanoic (C 18 ) fatty acids, which were extensively characterized by Fourier transform-infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1 H NMR). These N-acylated TMC derivatives (TMC n ) were used as cationic polymeric matrices for encapsulating anionic 18-base single-stranded thiophosphorylated oligonucleotides (ssONs), leading to the formation of polyplexes further characterized by zeta potential (ZP), dynamic light scattering (DLS), binding affinity, transfection efficiency and in vitro cytotoxicity assays. The results demonstrated that the length of the grafted hydrophobic N-acyl chain and the relative amino:phosphate groups ratio (N/P ratio) between the TMC derivatives and ssON played crucial roles in determining the physicochemical properties of the obtained nanocomplexes. While none of the tested derivatives showed appreciable cytotoxicity, the type of acyl chain had a remarkable influence on the cell transfection capacity of TMC-ssON nanocomplexes with the derivatives based on stearic acid showing the best performance based on the results of in vitro assays using a model cell line expressing luciferase (HeLa/Luc705).We acknowledge the financial support from the following Brazilian agencies: CAPES, FAPEMIG, CNPq, and FINEP. This work was co-financed by Fundação para a Ciência e a Tecnologia (FCT, Portugal) within the projects PTDC/CTM-NAN/NAN/115124/2009 and HMSP-ICT/0020/2010. Additionally, PMDM thanks the European Commission – Marie Curie Actions (PIEF-GA-2011-300485) for the postdoctoral fellowship. VL thanks the FCT fo the fellowship (SFRH/BPD/69110/2010). We are grateful to Dr Sandhra Carvalho (UFMG, Brazil) for the bioimaging analyses. The authors acknowledge the Centro de Materiais daUniversidade do Porto (CEMUP) for SEM and1H NMR analysis

AlN production in co-flow filtration mode at low pressures

In this work, the process for obtaining aluminum nitride in the combustion mode of co-flow filtration of a nitrogen–argon mixture was investigated. The combustion of granules consisting of aluminum and aluminum nitride as an inert diluent was studied under conditions of co-current filtration in a flow of nitrogen and a nitrogen–argon mixture in the range of a specific flow rate of 1.5–5.0 cm3/(scm2). It was found that the specific flow rate of the gas mixture and the amount of argon in the nitrogen–argon mixture had a significant effect on the rate and the temperature of combustion. The structure and phase composition of the synthesis products were studied. The maximum achieved yield of the AlN phase was 95 wt.%. Moreover, this method is energy efficient and allows the production of metal nitrides without the use of high-pressure reactors

Effect of Different Plant Growth Regulators on Callus Induction from Seeds of Chickpea (Cicer arietinum L.)

The present study was undertaken to develop a reproducible protocol for efficient in vitro callus initiation of chick pea (Cicer arietinum L.). The main objectives of this present study were to develop the optimal concentrations and combination of auxin and cytokinin for optimized callus induction from seeds as explants. Callus induction was initiated from seeds on MS media supplement, which varied according to the plant growth regulators treatment. Among the growth regulator combinations the highest rate of callus induction (85%) was observed in MS medium containing 2 mg L -1 of 2,4-Dichlorophenoxyacetic Acid (2,4-D), 2 mg L -1 Benzylaminopurine (BAP) showed higher percentage ( 63% ) of callus formation than 1- Naphthaleneacetic acid (NAA), which produced 49% of callus. There were significant differences in percentage of calli fresh/dry weights (g/jar) on the different initiation ( seven) medium used were the MS+2,4-D, MS+2,4-D +NAA+ BAP and MS+ BAP had the highest fresh/dry weights (g/jar) in both induction medium

Applications for ultimate spatial resolution in LASER based μ\mu-ARPES: A FeSe case study

Combining Angle resolved photoelectron spectroscopy (ARPES) and a $\mu$-focused Laser, we have performed scanning ARPES microscopy measurements of the domain population within the nematic phase of FeSe single crystals. We are able to demonstrate a variation of the domain population density on a scale of a few 10 $\mu$m while constraining the upper limit of the single domain size to less than 5 $\mu m$. This experiment serves as a demonstration of how combining the advantages of high resolution Laser ARPES and an ultimate control over the spatial dimension can improve investigations of materials by reducing the cross contamination of spectral features of different domains

The role of BAP in somatic embriogenesis induction from seed explants of Arachis species from Sections Erectoides and Procumbentes.

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