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Sample records for 4-go bloka chaehs

  1. Heterogeneous Fenton degradation of bisphenol A catalyzed by efficient adsorptive Fe3O4/GO nanocomposites.

    PubMed

    Hua, Zulin; Ma, Wenqiang; Bai, Xue; Feng, Ranran; Yu, Lu; Zhang, Xiaoyuan; Dai, Zhangyan

    2014-06-01

    A new method for the degradation of bisphenol A (BPA) in aqueous solution was developed. The oxidative degradation characteristics of BPA in a heterogeneous Fenton reaction catalyzed by Fe3O4/graphite oxide (GO) were studied. Transmission electron microscopic images showed that the Fe3O4 nanoparticles were evenly distributed and were ∼6 nm in diameter. Experimental results suggested that BPA conversion was affected by several factors, such as the loading amount of Fe3O4/GO, pH, and initial H2O2 concentration. In the system with 1.0 g L(-1) of Fe3O4/GO and 20 mmol L(-1) of H2O2, almost 90% of BPA (20 mg L(-1)) was degraded within 6 h at pH 6.0. Based on the degradation products identified by GC-MS, the degradation pathways of BPA were proposed. In addition, the reused catalyst Fe3O4/GO still retained its catalytic activity after three cycles, indicating that Fe3O4/GO had good stability and reusability. These results demonstrated that the heterogeneous Fenton reaction catalyzed by Fe3O4/GO is a promising advanced oxidation technology for the treatment of wastewater containing BPA.

  2. Highly Efficient Antibacterial and Pb(II) Removal Effects of Ag-CoFe2O4-GO Nanocomposite.

    PubMed

    Ma, Shuanglong; Zhan, Sihui; Jia, Yanan; Zhou, Qixing

    2015-05-20

    Ag-CoFe2O4-graphene oxide (Ag-CoFe2O4-GO) nanocomposite was synthesized by doping silver and CoFe2O4 nanoparticles on the surface of GO, which was used to purify both bacteria and Pb(II) contaminated water. The Ag-CoFe2O4-GO nanomaterial was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), and magnetic property tests. It can be found that Ag-CoFe2O4-GO nanocomposite exhibited excellent antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus compared with CoFe2O4, Ag-CoFe2O4, and CoFe2O4-GO composite. This superior disinfecting effect was possibly attributed to the combination of GO nanosheets and Ag nanoparticles. Several antibacterial factors including temperature, time, and pH were also investigated. It was obvious that E. coli was more susceptible than S. aureus toward all the four types of nanomaterials. The structural difference of bacterial membranes should be responsible for the resistant discrepancy. We also found that Ag-CoFe2O4-GO inactivated both bacteria in an irreversibly stronger manner than Ag-CoFe2O4 and CoFe2O4-GO. The Pb(II) removal efficiency with all the nanomaterials showed significant dependence on the surface area and zeta potential of the materials. In this work, not only did we demonstrate the simultaneous superior removal efficiency of bacteria and Pb(II) by Ag-CoFe2O4-GO but also the antibacterial mechanism was discussed to have a better understanding of the interaction between Ag-CoFe2O4-GO and bacteria. In a word, taking into consideration the easy magnetic separation, bulk availability, and irreversibly high antibacterial activity of Ag-CoFe2O4-GO, it is the very promising candidate material for advanced antimicrobial or Pb(II) contaminated water treatment.

  3. Covalently bonded sulfonic acid magnetic graphene oxide: Fe3O4@GO-Pr-SO3H as a powerful hybrid catalyst for synthesis of indazolophthalazinetriones.

    PubMed

    Doustkhah, Esmail; Rostamnia, Sadegh

    2016-09-15

    Multistep synthesis of covalently sulfonated magnetic graphene oxide was achieved by starting from Hummer's method to produce graphene oxide (GO) from chemical oxidation of graphite. Then, GO nanosheets were applied to support Fe3O4 nanoparticles (Fe3O4@GO) using co-precipitation method in the presence of GO sheets. This strategy led to formation of uniform particles of Fe3O4 on the surface of GO sheets. Then, it was sulfonated (Fe3O4@GO-Pr-SO3H) through modification with 3-mercaptopropyltrimethoxysilane (MPTMS) and subsequent oxidation with hydrogen peroxide (H2O2). In comparison, the covalently bonded propyl sulfonic acid groups were more prevailing rather to sulfonic acids of GO itself. The proposed catalyst was more active and recyclable at least for 11 runs.

  4. Efficient alkene hydrogenation over a magnetically recoverable and recyclable Fe3O4@GO nanocatalyst using hydrazine hydrate as the hydrogen source.

    PubMed

    Mondal, John; Nguyen, Kim Truc; Jana, Avijit; Kurniawan, Karina; Borah, Parijat; Zhao, Yanli; Bhaumik, Asim

    2014-10-18

    Magnetic Fe3O4 nanoparticles embedded in graphene oxide (Fe3O4@GO) behave as a highly efficient and reusable heterogeneous nanocatalyst for alkene hydrogenation in EtOH at 80 °C temperature using hydrazine hydrate as the hydrogen source to deliver the corresponding alkanes in good to excellent yields together with high TOF (>4500 h(-1)) within a 4-20 h reaction time.

  5. Synthesis of water-dispersible poly-l-lysine-functionalized magnetic Fe3O4-(GO-MWCNTs) nanocomposite hybrid with a large surface area for high-efficiency removal of tartrazine and Pb(II).

    PubMed

    Hu, Dan; Wan, Xiaodong; Li, Xiaohui; Liu, Jianguo; Zhou, Chunhua

    2017-03-07

    In this study, a novel, effective and environment-friendly methods was used to prepare poly-l-lysine (PLL)-functionalized magnetic Fe3O4-(GO-MWCNTs) hybrid composite with large surface area and abundant hydroxyl and amino groups. The as-prepared PLL-Fe3O4-(GO-MWCNTs) nanocomposite was systematically characterized by FT-IR, XRD, TGA, SEM, TEM, VSM and EDX. The PLL-Fe3O4-(GO-MWCNTs) hybrid composite exhibited excellent adsorption performance for the removal of a dye (tartrazine) and a heave metal (Pb(II)). The result showed that adsorption of Pb(II) reached equilibrium in 30min and adsorption of tartrazine reached equilibrium in approximately 60min. Most importantly, PLL-Fe3O4-(GO-MWCNTs) hybrid possesses high adsorption capacity, rapid separation, and less time-consuming. The equilibrium adsorption capacity was 1038.42mgg(-1) for Pb(II) and 775.19mgg(-1) for tartrazine under the optimal conditions. These two pollutants removal were found to obey Langmuir adsorption model, while the kinetics of adsorption followed pseudo-second-order kinetic model. A possible adsorption mechanism has been proposed where the chelation between PLL and Pb(II) or electrostatic interaction between GO and tartrazine. These results demonstrated the potential applications of PLL-Fe3O4-(GO-MWCNTs) hybrid composite in deep-purification of polluted water.

  6. Remote controlled drug release from multi-functional Fe3O4/GO/Chitosan microspheres fabricated by an electrospray method.

    PubMed

    Li, Sheng; Xiao, Ling; Deng, Hongbing; Shi, Xiaowen; Cao, Qihua

    2017-03-01

    The construction of multifunctional microspheres for remote controlled drug release requires the exquisite selection of composite materials and preparation approaches. In this study, chitosan, an amino polysaccharide, was blended with inorganic nanocomponents, Fe3O4 and graphene oxide (GO) and electrosprayed to fabricate uniform microspheres with the diameters ranging from 100μm to 1100μm. An anti-cancer drug, doxorubicin (DOX), was loaded to the microspheres by an adsorption or embedding method. The microsphere is responsive to magnetic fields due to the presence of Fe3O4, and the incorporation of GO enhanced the drug loading capacity. The fast stimuli-responsive release of DOX can be facilely controlled by using NIR irradiation due to the strong photo-thermal conversion of Fe3O4 and GO. In addition, ultrasound was used as another external stimulus for DOX release. The results suggest the Fe3O4/GO/Chitosan microspheres fabricated by the electrospray method provide an efficient platform for remote controlled drug release, which may have potential applications in drug eluting microspheres.

  7. BC4GO: a full-text corpus for the BioCreative IV GO Task

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Database (MOD) groups. Due to its manual nature, this task is time-consuming and labor-intensive, and thus considered one of the bottlenecks in literature curation. There have been many previous attempts a...

  8. Dithiocarbamate to modify magnetic graphene oxide nanocomposite (Fe3O4-GO): A new strategy for covalent enzyme (lipase) immobilization to fabrication a new nanobiocatalyst for enzymatic hydrolysis of PNPD.

    PubMed

    Heidarizadeh, Mohammad; Doustkhah, Esmail; Rostamnia, Sadegh; Rezaei, Parisa Fathi; Harzevili, Farshad Darvishi; Zeynizadeh, Behzad

    2017-03-29

    Immobilization of lipase was successfully achieved on the surface of magnetically separable Fe3O4/graphene oxide (GO) via a post-modification. This post modification was achieved in alternation to glutaraldehyde post-modification. The activity of immobilized lipase had not a significant loss in the activity while on the other hand, it is simply extractable (by keeping its major activity) from reaction crude by a magnet. Each step of immobilization was carefully monitored by characterization and all were successfully proved. SEM, TEM, XRD, EDX, and FTIR were used to characterize the support and immobilization process.

  9. Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein.

    PubMed

    Huang, Yanhua; Wang, Yuzhi; Pan, Qi; Wang, Ying; Ding, Xueqin; Xu, Kaijia; Li, Na; Wen, Qian

    2015-06-02

    Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe3O4@GO) to form Fe3O4@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe3O4@GO-DES, and the results indicated the successful preparation of Fe3O4@GO-DES. The UV-vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe3O4@GO-DES. Comparison of Fe3O4@GO and Fe3O4@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe3O4@GO-DES performs better than Fe3O4@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005 mol L(-1) Na2HPO4 contained 1 mol L(-1) NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled.

  10. Blepharoplasty - slideshow

    MedlinePlus

    ... Indications URL of this page: //medlineplus.gov/ency/presentations/100183.htm Blepharoplasty - series—Indications To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  11. Composites of aminodextran-coated Fe3O4 nanoparticles and graphene oxide for cellular magnetic resonance imaging.

    PubMed

    Chen, Weihong; Yi, Peiwei; Zhang, Yi; Zhang, Liming; Deng, Zongwu; Zhang, Zhijun

    2011-10-01

    Formation of composites of dextran-coated Fe(3)O(4) nanoparticles (NPs) and graphene oxide (Fe(3)O(4)-GO) and their application as T(2)-weighted contrast agent for efficient cellular magnetic resonance imaging (MRI) are reported. Aminodextran (AMD) was first synthesized by coupling reaction of carboxymethyldextran with butanediamine, which was then chemically conjugated to meso-2,3-dimercaptosuccinnic acid-modified Fe(3)O(4) NPs. Next, the AMD-coated Fe(3)O(4) NPs were anchored onto GO sheets via formation of amide bond in the presence of 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC). It is found that the Fe(3)O(4)-GO composites possess good physiological stability and low cytotoxicity. Prussian Blue staining analysis indicates that the Fe(3)O(4)-GO nanocomposites can be internalized efficiently by HeLa cells, depending on the concentration of the composites incubated with the cells. Furthermore, compared with the isolated Fe(3)O(4) NPs, the Fe(3)O(4)-GO composites show significantly enhanced cellular MRI, being capable of detecting cells at the iron concentration of 5 μg mL(-1) with cell density of 2 × 10(5) cells mL(-1), and at the iron concentration of 20 μg mL(-1) with cell density of 1000 cells mL(-1).

  12. Facile synthesis of manganese ferrite/graphene oxide nanocomposites for controlled targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Wang, Guangshuo; Ma, Yingying; Zhang, Lina; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Che, Hongwei; Bai, Yongmei; Hou, Junxian

    2016-03-01

    In this study, manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe2O4 nanoparticles having diameters of 5-13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe2O4/GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe2O4/GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe2O4/GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way.

  13. Diagnostic peritoneal lavage - slideshow

    MedlinePlus

    ... Indication URL of this page: //medlineplus.gov/ency/presentations/100159.htm Diagnostic peritoneal lavage - series—Indication To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  14. Ankle sprain - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100209.htm Ankle sprain - Series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  15. Parathyroidectomy - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100093.htm Parathyroidectomy - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  16. Hysterectomy - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100029.htm Hysterectomy - Series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  17. Anal fissure - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100154.htm Anal fissure - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  18. Hydrocele repair - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100163.htm Hydrocele repair - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  19. Abdominal exploration - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100049.htm Abdominal exploration - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  20. Skin graft - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  1. Breast reduction (mammoplasty) - slideshow

    MedlinePlus

    ... Indications URL of this page: //medlineplus.gov/ency/presentations/100189.htm Breast reduction (mammoplasty) - series—Indications To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  2. Biliary obstruction - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100199.htm Biliary obstruction - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  3. Scar revision - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100098.htm Scar revision - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  4. Tonsillectomy - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100122.htm Tonsillectomy - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  5. Eardrum repair - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100015.htm Eardrum repair - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  6. Fe3O4 nanoparticles on graphene oxide sheets for isolation and ultrasensitive amperometric detection of cancer biomarker proteins.

    PubMed

    Sharafeldin, Mohamed; Bishop, Gregory W; Bhakta, Snehasis; El-Sawy, Abdelhamid; Suib, Steven L; Rusling, James F

    2017-05-15

    Ultrasensitive mediator-free electrochemical detection for biomarker proteins was achieved at low cost using a novel composite of Fe3O4 nanoparticles loaded onto graphene oxide (GO) nano-sheets (Fe3O4@GO). This paramagnetic Fe3O4@GO composite (1µm size range) was decorated with antibodies against prostate specific antigen (PSA) and prostate specific membrane antigen (PSMA), and then used to first capture these biomarkers and then deliver them to an 8-sensor detection chamber of a microfluidic immunoarray. Screen-printed carbon sensors coated with electrochemically reduced graphene oxide (ERGO) and a second set of antibodies selectively capture the biomarker-laden Fe3O4@GO particles, which subsequently catalyze hydrogen peroxide reduction to detect PSA and PSMA. Accuracy was confirmed by good correlation between patient serum assays and enzyme-linked immuno-sorbent assays (ELISA). Excellent detection limits (LOD) of 15 fg/mL for PSA and 4.8 fg/mL for PSMA were achieved in serum. The LOD for PSA was 1000-fold better than the only previous report of PSA detection using Fe3O4. Dynamic ranges were easily tunable for concentration ranges encountered in serum samples by adjusting the Fe3O4@GO Concentration. Reagent cost was only $0.85 for a single 2-protein assay.

  7. Ag3PO4/graphene-oxide composite with remarkably enhanced visible-light-driven photocatalytic activity toward dyes in water.

    PubMed

    Chen, Guodong; Sun, Meng; Wei, Qin; Zhang, Yongfang; Zhu, Baocun; Du, Bin

    2013-01-15

    Ag(3)PO(4)/graphene-oxide (Ag(3)PO(4)/GO) composite has been synthesized by a liquid phase deposition method, and used for the photodegradation of organic dyes in water under visible light. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, N(2) sorption-desorption, and UV-vis diffuse reflectance spectra. The SEM image indicated that Ag(3)PO(4) particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of Ag(3)PO(4)/GO composite was evaluated by decomposing of dyes (such as methyl orange, rhodamine B) in water under visible or UV-vis light irradiation. The degradation results indicated that the photocatalytic performance of Ag(3)PO(4)/GO was greatly enhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers. The Ag(3)PO(4)/GO composite with GO content of 15 wt.% exhibited superior activity under visible light irradiation. After 50 min of reaction, the degradation ratio of MO was about 86.7%, while RhB solution could be completely degraded within 30 min of reaction. Further study proved that the direct oxidation of pollutants by holes has played a major role in the degradation process. The results of this work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance.

  8. Graphene oxide/Fe3O4/chitosan nanocomposite: a recoverable and recyclable adsorbent for organic dyes removal. Application to methylene blue

    NASA Astrophysics Data System (ADS)

    Tran, Hoang V.; Bui, Lieu T.; Dinh, Thuy T.; Le, Dang H.; Huynh, Chinh D.; Trinh, Anh X.

    2017-03-01

    In this research, the potential of chitosan/Fe3O4/graphene oxide (CS/Fe3O4/GO) nanocomposite for efficient removal of methylene blue (MB) as a cationic dye from aqueous solutions was investigated. For this purpose, first, graphene oxide (GO) was prepared from pencil’s graphite by Hummer’s method, then after, CS/Fe3O4/GO was synthesized via chemical co-precipitation method from a mixture solution of GO, Fe3+, Fe2+ and chitosan. The synthesized CS/Fe3O4/GO was characterized by XRD, VSM and SEM techniques. Also, the various parameters affecting dye removal were investigated. Dye adsorption equilibrium data were fitted well to the Langmuir isotherm rather than Freundlich isotherm. The maximum monolayer capacity (q max), was calculated from the Langmuir as 30.10 mg · g‑1. The results show that, CS/Fe3O4/GO nanocomposite, can be used as a cheap and efficient adsorbent for removal of cationic dyes from aqueous solutions.

  9. Fe{sub 3}O{sub 4}@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes

    SciTech Connect

    He, Guangyu; Liu, Weifeng; Sun, Xiaoqiang; Chen, Qun; Wang, Xin; Chen, Haiqun

    2013-05-15

    Highlights: ► The Fe{sub 3}O{sub 4}@GO composite was prepared by a facile co-precipitation method. ► Fe{sub 3}O{sub 4} nanoparticles are well distributed on GO nanosheets. ► Fe{sub 3}O{sub 4}@GO was for the first time explored as a catalyst to reduce nitroarenes. ► Fe{sub 3}O{sub 4}@GO exhibits higher catalytic activity. ► The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe{sub 3}O{sub 4}@graphene oxide (Fe{sub 3}O{sub 4}@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N{sub 2} adsorption–desorption measurements. The results demonstrated that the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe{sub 3}O{sub 4}@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min{sup −1}, forty five times that of the commercial Fe{sub 3}O{sub 4} NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability.

  10. National Dam Inspection Program. Fishpond Dam (NDS ID Number PA-899, DER ID Number 19-81), Susquehanna River Basin, Unnamed Tributary to Roaring Creek, Columbia County, Pennsylvania. Phase I Inspection Report.

    DTIC Science & Technology

    1980-06-01

    do not appear to be susceptible to massive landslides which would affect the storage volume of the reservoir or cause overtopping of the dam by...XC 4- .. .. ~ i OSO - 9L4 4 0A000000 - II 4 ~go 7. 0j 0F 0 03 cc 0 -r 0,0, 0 I I - .g j. N I; . CL 0j% - i of - In M,.. K 4 1~ -zA 4&~~ON _-X . .- ’-1

  11. The Five Point Plan: Foundational Transformation of the South Sudan Armed Forces

    DTIC Science & Technology

    2012-05-01

    PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (00-MM-YYYY) 1-05-2012 12. REPORT TYPE Master of Military Studies Research ...reserve to assist in infrastructure related projects while simultaneously creating a marketable future workforce. These forces could be utilized in the...in Chief DCOGS HQTRS SSAF CG SSAF DIV x 6 CG SSAF BDE x 4 GoSS / NSC DCOGS SSAF Reserve Support / Training Institutions (1) Medical

  12. High catalytic activity of magnetic CuFe2O4/graphene oxide composite for the degradation of organic dyes under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Xing, Xiang; Xie, Huifang; Sheng, Qi; Qu, Hongxia

    2016-09-01

    Magnetic CuFe2O4/graphene oxide composite (CuFe2O4/GO) has been synthesized by hydrothermal method and showed excellent visible-light-photocatalytic activity for the degradation of different dyes as Rhodamine B (RhB) and acid orange II (AO7) with no need of H2O2. The Structure and morphology were investigated by XRD, FTIR and TEM and the performance of the catalyst was systematically investigated under various experimental conditions as pH, the dosage of catalyst, dye initial concentration, etc. The dyes degradation on CuFe2O4/GO was also remained in a level in the presence of *OH2- radical scavenger (2-propanol), while it decreased in the presence of *O2- radical scavenger (benzoquinone) and h+ radical scavenger (ammonium oxalate), indicating that *O2- and h+ radicals were responsible for the dye degradation. The magnetic CuFe2O4/GO composite shows potential applications in organic dye water treatment due to its magnetically recyclability and powerful visible-light-photocatalytic activity.

  13. Adsorption mechanism of magnetically separable Fe3O4/graphene oxide hybrids

    NASA Astrophysics Data System (ADS)

    Ouyang, Ke; Zhu, Chuanhe; Zhao, Ya; Wang, Leichao; Xie, Shan; Wang, Qun

    2015-11-01

    A reclaimable Fe3O4/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (qm) of the Fe3O4/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π-π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe3O4/GO hybrid. Therefore, the Fe3O4/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

  14. Mixed hemimicelles solid-phase extraction of cephalosporins in biological samples with ionic liquid-coated magnetic graphene oxide nanoparticles coupled with high-performance liquid chromatographic analysis.

    PubMed

    Wu, Jianrong; Zhao, Hongyan; Xiao, Deli; Chuong, Pham-Huy; He, Jia; He, Hua

    2016-07-08

    A novel mixed hemimicelles solid phase extraction based on magnetic graphene oxide (Fe3O4/GO) and ionic liquid (IL) was developed for the simultaneous extraction and determination of trace cephalosporins in spiked human urine. The high surface area and excellent adsorption capacity of the graphene oxide after modification with1-hexadecyl-3-methylmidazoliumbromide(C16mimBr) were utilized adequately in the solid phase extraction(SPE) process. A comprehensive study of the parameters affecting the extraction recovery, such as the zeta-potential of magnetic graphene oxide, amounts of magnetic graphene oxide and surfactant, pH of solution, ionic strength, extraction time, and desorption condition were optimized. A comparative study on the use of different surfacant-coated Fe3O4/GO NPs as sorbents was presented. Good linearity (R(2)>0.9987) for all calibration curves was obtained. The LODs were ranged between 0.6 and 1.9ng mL(-1) for the cephalosporins and the LOQs were 1.5 to 5.5, respectively. Satisfactory recoveries(84.3% to 101.7%)and low relative standard deviations from 1.7% to 6.3% in biological matrices were achieved. The mixed hemimicelles magnetic SPE (MSPE) method based on ILs and Fe3O4/GO NPs magnetic separation has ever been successfully used for pretreatment of complex biological samples.

  15. An "in-electrode"-type immunosensing strategy for the detection of squamous cell carcinoma antigen based on electrochemiluminescent AuNPs/g-C3N4 nanocomposites.

    PubMed

    Wu, Lin; Hu, Yufang; Sha, Yuhong; Li, Wenrou; Yan, Tiantian; Wang, Sui; Li, Xing; Guo, Zhiyong; Zhou, Jun; Su, Xiurong

    2016-11-01

    A novel "in-electrode"-type electrochemiluminescence (ECL) immunosensor for the sensitive detection of squamous cell carcinoma antigen (SCCA) was constructed using magnetic graphene oxide (nanoFe3O4@GO) and Au nanoparticles/graphitic-phase carbon nitride (AuNPs/g-C3N4). The capture probe was prepared by immobilizing the primary antibody of SCCA (Ab1) on the nanoFe3O4@GO, while the AuNPs/g-C3N4 nanocomposites labelled the secondary antibody of SCCA (Ab2), which acted as a signal tag. The recognition scaffold was the following: the capture probe was immobilized onto the magnetic electrode surface that caught the target SCCA and finally allowed the immobilization of the signal tag via the interaction between antigen and antibody. Importantly, a high ECL signal could be obtained due to the unique immunocomplex, which ensured all of the g-C3N4 on the outmost plane were directly fixed onto the electrode surface and became part of the electrode surface. This resulted in an enhanced efficiency of the g-C3N4 for electrochemical luminescence, thus extending the outer Helmholtz plane (OHP) of the proposed electrode and leading to high sensitivity. Taking advantage of both nanoFe3O4@GO and AuNPs/g-C3N4, the ECL intensity was found to increase logarithmically with SCCA concentration in a wide linear range from 0.001 to 10ng/mL and with a detection limit of 0.4pg/mL. The proposed "in-electrode"-type ECL immunosensor was used to analyse SCCA in human serum, and satisfactory recoveries were obtained, indicating that the proposed method was promising for practical applications in the clinical diagnosis of SCCA.

  16. Active and Passive Remote Sensing of Ice

    DTIC Science & Technology

    1991-11-15

    Oberhettinger, F., and L. Badi, Tables of Laplace Transforms, Springer-Verlag, New York, 1973. Murat Emre Veysoglu was born in Ankara, Turkey in 1968. He...8217 ~ & 0 3~ z oo 0O .4 =. - g 0 1 o ~ - v 1- 0 o (aw3 4 V) 4 N’Om V= bo -0 0 o’* ra% 4’.~S -’u4 .O -4 goQ 03 4 ~ 𔃺 41 0. ’at. 0 4 4c -4 0 :a~ ULa ~N

  17. (Fe3O4)-graphene oxide-SO3H as a new magnetic nanocatalyst for electro-oxidation and determination of selected parabens.

    PubMed

    Hasanzadeh, Mohammad; Shadjou, Nasrin

    2013-07-01

    For the first time magnetic graphene oxide functionalized by chlorosulfonic acid Fe3O4-GO-SO3H was used for electrode modification and electrocatalytic oxidation of three selected parabens. Scanning electron microscopy (SEM) and X-ray diffraction techniques are utilized in order to study the surface morphology of the modified electrode. The modified electrode was applied for parabens detection using cyclic voltammetry (CV), chronoamperometry, and amperometry methods. The modified electrode shows many advantages as a parabens sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, excellent catalytic activity, short response time, long-term stability and remarkable antifouling property toward parabens.

  18. Mutagenic Potential of 1-Acetyloctahydro-3,5,7-Trinitro-1,3,5,7-Tetrazocine (SEX) and 1-Acetylhexahydro-3,5-Dinitro-1,3,5-Triazine (TAX).

    DTIC Science & Technology

    1983-11-01

    detection of carcinogens and mutagens with Salmonella/mammalian microsome mutagenicity test. Mutat Res 1975;31: 347 -364. 3. LAIR SOP OP-STX-1, Ames...ao 0 Clcc C) L-t N0 coco 0 N co N 0 0 cNao in- C)O CD0 Cc 00~ Cu S 0A co Cj C1 c ’) 0C0 C~j 1-4 *Go 4aj 4-i U . C\\ wej Cu ai -4- 0 0 ca 00 =ncx 0o. 60

  19. The Army Leader Requirements Task Analysis: Noncommissioned Officer Results

    DTIC Science & Technology

    1990-08-01

    21 P . Maintain 2-way information exchange with superiors..17 Q. Monitor and evaluate performance.................... 38 R. Conduct counseling...ending...performed within a limited period of time" (Melching & Borcher, 1973, p . 3). Had the two latter criteria been strictly adhered to, critical Army...V4i p ~. 0 45 ~ g in0~’ 4 0 ) Ir𔃾I in 𔃾 :D N -A~ O 3V4 𔃾 ’.o.0 I � 0% 1 in ’.4 go ’.4 en r. 1-4 0 W -I OW 0 0 44 NV A 0 CD1 en N tn t- in So 9) t

  20. Fleet Mooring Leg Design Program Documentation. Volume 4. Source Listings: Query, Preprocessor and Simple Leg.

    DTIC Science & Technology

    1982-12-01

    blank) gala 29 gota 59 20 continue J-l SO contianue do 60 i-I1,4 f I(jj n) gala 199I Ie(j -ext (ii J-j+1 69 continue if (jgf n) gala 199 do 70 i-j~n...20)-tanfb*(v-vc3I/h gota 330 1360 continue tfivc3 ge vc4lgoto 1400 ner r-4 gala 6000 1400 continue ,f(v It VC4lgoto 14S0 ipt-4 go010 2000 1410 1-Ivc3

  1. [Adsorption of methylene blue from aqueous solution onto magnetic Fe3O4/ graphene oxide nanoparticles].

    PubMed

    Chang, Qing; Jiang, Guo-Dong; Hu, Meng-Xuan; Huang, Jia; Tang, He-Qing

    2014-05-01

    A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe3O4/graphene oxide (Fe3O4/ GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe3O4/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg.g-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment.

  2. Graphene oxide amplified electrochemiluminescence of graphitic carbon nitride and its application in ultrasensitive sensing for Cu(2+).

    PubMed

    Xia, Binyuan; Chu, Mingfu; Wang, Shaofei; Wang, Wanqing; Yang, Shanli; Liu, Chengbin; Luo, Shenglian

    2015-09-03

    Here for the first time, we present a novel electrochemiluminescence (ECL) sensor based on graphitic carbon nitride/graphene oxide (g-C3N4/GO) hybrid for the ultrasensitive detection of Cu(2+), which is a common pollutant in environmental system. The g-C3N4/GO shows stable ECL signal in the presence of the self-produced coreactant from oxygen reduction, and the ECL signal could be effectively quenched by Cu(2+), the possible ECL detection mechanism has been proposed in detail. GO can not only significantly enhance the cathodic ECL signal of g-C3N4 (∼3.8 times), but also serve as immobilization platform for g-C3N4. After optimization of experimental conditions, the proposed protocol can offer an ultrasensitive, highly selective and recyclable method for the detection of Cu(2+) with a low detection limit of 1.0 × 10(-11) M and a wide linear range from 1.0 × 10(-11) to 1.0 × 10(-7) M. Moreover, the practicability of the ECL sensor in real wastewater samples is also tested, showing that the proposed ECL sensor could be a promising alternative method for the emergency and routine monitoring of Cu(2+) in real sample.

  3. A new kinetic-mechanistic approach to elucidate electrooxidation of doxorubicin hydrochloride in unprocessed human fluids using magnetic graphene based nanocomposite modified glassy carbon electrode.

    PubMed

    Soleymani, Jafar; Hasanzadeh, Mohammad; Shadjou, Nasrin; Khoubnasab Jafari, Maryam; Gharamaleki, Jalil Vaez; Yadollahi, Mehdi; Jouyban, Abolghasem

    2016-04-01

    A novel magnetic nanocomposite was synthesized in one step using polymerization of magnetic graph oxide grafted with chlorosulfonic acid (Fe3O4-GO-SO3H) in the presence of polystyrene. The prepared magnetic nanocomposite was characterized using transmission electron microscopy (TEM), dynamic differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), (Thermo-gravimetric/differential thermal analysis (DTA)), Fourier transform infrared (FTIR), and UV-Vis techniques. Magnetic nanocomposite was casted on the surface of the glassy carbon electrode (PS/Fe3O4-GO-SO3H/GCE) and used for the detection and determination of doxorubicin hydrochloride (DOX) in human biological fluids. The cyclic voltammograms (CVs) of the modified electrode in aqueous solution displayed a pair of well-defined, stable and irreversible reductive/oxidation redox systems. CV study indicated that the oxidation process is irreversible and adsorption controlled. In addition, CV results indicated that DOX is oxidized via two electrons and three protons which is an unusual approach for the oxidation of DOX. A sensitive and time-saving procedure was developed for the analysis of DOX in plasma, cerebrospinal fluid, and urine with detection limit of 4.9 nM, 14 nM and 4.3 nM, respectively.

  4. Synthesis and characterization of Ag₃PO₄ immobilized with graphene oxide (GO) for enhanced photocatalytic activity and stability over 2,4-dichlorophenol under visible light irradiation.

    PubMed

    Chen, Xiao-juan; Dai, You-zhi; Wang, Xing-yan; Guo, Jing; Liu, Tan-hua; Li, Fen-fang

    2015-07-15

    A series of visible-light responsive photocatalysts prepared using Ag3PO4 immobilized with graphene oxide (GO) with varying GO content were obtained by an electrostatically driven method, and 2,4-dichlorophenol (2,4-DCP) was used to evaluate the performance of the photocatalysts. The composites exhibited superior photocatalytic activity and stability compared with pure Ag3PO4. When the content of GO was 5%, the degradation efficiency of 2,4-DCP could reach 98.95%, and 55.91% of the total organic (TOC) content was removed within 60 min irradiation. Meanwhile, the efficiency of 91.77% was achieved for 2,4-DCP degradation even after four times of recycling in the photocatalysis/Ag3PO4-GO (5%) system. Reactive species of O2(˙-), OH˙ and h(+) were considered as the main participants for oxidizing 2,4-DCP, as confirmed by the free radical capture experiments. And some organic intermediates including 4-chlorophenol (4-CP), hydroquinone (HQ), benzoquinone (BZQ), 2-chlorohydroquinone and hydroxyhydroquinone (HHQ) were detected by comparison with the standard retention times from the high performance liquid chromatography (HPLC). In short, the enhanced photocatalytic property of Ag3PO4-GO was closely related to the strong absorption ability of GO relative to 2,4-DCP, the effective separation of photogenerated electron-hole pairs, and the excellent electron capture capability of GO.

  5. Global Positioning System - A Modification to the Baseline Satellite Constellation for Improved Geometric Performance.

    DTIC Science & Technology

    1984-12-01

    84D-4 DTC Approved for public releas; distribution unlimitedD AFI T/G/ENG/84D-4 GLOBAL POSITIONING SYSTEM - A MODIFICATION TO THE BASELINE STELLITE ...TO 401 400 IF(MBS.LT.4) GO TO 479 401 BOX-10. IFR(ISCHP. EQ. I) GO TO 405 CALL TRAT (HSS,KCN,KXX) GO TO 410 405 KOT-IK IF(LOC.EQ.2.OR.LOC.EQ.3...KOTNSS CALL TAILL (KOT,KCat,K0XX) 410 00 430 M- 1, KCO 00 415 LPQ.LPN,4 IS IC(LPQ ).IOSMAI) 415 CONT I ME CALL IU.LNE (USJ, I sI C,I.ULtI) IFQ(UE1.GT.9OX

  6. Typical Expendable Bathythermograph(TXBT) Data Base, Indian Ocean. Reference Publication

    DTIC Science & Technology

    1982-08-01

    34) OWr 440 1 4 C. OUlU 1 4 P1-1 # 4 Go0, 0.0 r, 1.0 ID r4 v It 4 44 0 4 4 4. -S 4 4V 4 ) #IO’) P-Fl 411m 0.04 C-P. (.0(04 &nV)d4 C, w4 FNP ’)w SAP 4 ) 𔃻...w~, 44 4-𔃺 U, 40’ i. 4U 𔃺 F =pV~ 44 O Nn N 00 tz.4 . " a4 4 4 4D.- - -N li-K 41 4.ý .CC* 0 z. 4ý Z It C4N4 4 () a EVC 4 0 1ON1 p- r, In ftW0 4 a

  7. Modeling of Shadows in Radar Clutter.

    DTIC Science & Technology

    1980-07-01

    0005 wAITE 46.20001 TITLE 060 WRITE 46.21331 N!.4V.NC.NTIN.N4TOUT.M4TIRL.1PAUtF.NETNGO 0007 N1.1 0006 4 2WNI*NCONV 0000 N43 .42 * PIC 0010 NA-43#HE 0011...PARTMtON PARAM7!E C EPpTI. SEP.) PCtNTS ARE %fLPCTEfW FQROS THE 0ATA UNITS. c PEA) TM" SEOU.INCF NUftERS POrN TeE CHOSEN 0A74 cjo ItSOPOPM A"OfS so2 IN...34 MCM WASIARLE FOR Iwo, CLU6Tal 00*?0 00 M.0TMI 006444 gu. 910V 006? so sOMITIN C TilPt PIC W e"RijiUO 0011 CPIOTRJI TOTALIJI 1/00141014JI 60S4Go o ca its

  8. Nacre-like calcium carbonate controlled by ionic liquid/graphene oxide composite template.

    PubMed

    Yao, Chengli; Xie, Anjian; Shen, Yuhua; Zhu, Jinmiao; Li, Hongying

    2015-06-01

    Nacre-like calcium carbonate nanostructures have been mediated by an ionic liquid (IL)-graphene oxide (GO) composite template. The resultant crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffractometry (XRD). The results showed that either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) or graphene oxide can act as a soft template for calcium carbonate formation with unusual morphologies. Based on the time-dependent morphology changes of calcium carbonate particles, it is concluded that nacre-like calcium carbonate nanostructures can be formed gradually utilizing [BMIM]BF4/GO composite template. During the process of calcium carbonate formation, [BMIM]BF4 acted not only as solvents but also as morphology templates for the fabrication of calcium carbonate materials with nacre-like morphology. Based on the observations, the possible mechanisms were also discussed.

  9. Poly(2-aminobenzothiazole)-coated graphene oxide/magnetite nanoparticles composite as an efficient sorbent for determination of non-steroidal anti-inflammatory drugs in urine sample.

    PubMed

    Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira

    2016-02-26

    In this study, for the first time, 2-aminobenzothiazole monomer was polymerized on Fe3O4 NPs, graphene oxide/Fe3O4 (GO/Fe3O4) and graphene/Fe3O4 (G/Fe3O4) nanocomposites. The synthesized magnetic nanosorbents were characterized by various techniques. The extraction ability of these nanosorbents including Fe3O4, GO/Fe3O4, G/Fe3O4, Fe3O4@poly(2-aminobenzothiazole) (Fe3O4@PABT), GO/Fe3O4@PABT and G/Fe3O4@PABT were compared for dispersive-micro-solid phase extraction of three non-steroidal anti-inflammatory drugs. The results revealed that GO/Fe3O4@PABT nanocomposite demonstrates higher extraction efficiency for naproxen, diclofenac and ibuprofen as selected model analytes. Following the sorption and elution steps, the model analytes were quantified by high performance liquid chromatography-photo diode array detection. Afterwards, a central composite design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. Under the optimized conditions, the limits of detection and linear dynamic ranges were achieved in the range of 0.07-0.3 μg L(-1) and 0.25-2000 μg L(-1), respectively. The percent of extraction recovery was 87.4, 85.5 and 90.5% for naproxen, diclofenac and ibuprofen, respectively. The obtained relative standard deviation (n=5) was 7.2, 5.4 and 6.4% for naproxen, diclofenac and ibuprofen, respectively. Ultimately, this method was employed for urinary monitoring of the target analytes and satisfactory results were obtained.

  10. Developing a social practice‐based typology of British drinking culture in 2009–2011: implications for alcohol policy analysis

    PubMed Central

    Ally, Abdallah K.; Lovatt, Melanie; Meier, Petra S.; Brennan, Alan

    2016-01-01

    Abstract Background and aims The concept of national drinking culture is well established in research and policy debate, but rarely features in contemporary alcohol policy analysis. We aim to demonstrate the value of the alternative concept of social practices for quantitatively operationalizing drinking culture. We discuss how a practice perspective addresses limitations in existing analytical approaches to health‐related behaviour before demonstrating its empirical application by constructing a statistical typology of British drinking occasions. Design Cross‐sectional latent class analysis of drinking occasions derived from retrospective 1‐week drinking diaries obtained from quota samples of a market research panel. Occasions are periods of drinking with no more than 2 hours between drinks. Setting Great Britain, 2009–11. Cases A total of 187 878 occasions nested within 60 215 nationally representative adults (aged 18 + years). Measurements Beverage type and quantity per occasion; location, company and gender composition of company; motivation and reason for occasion; day, start‐time and duration of occasion; and age, sex and social grade. Findings Eight occasion types are derived based primarily on parsimony considerations rather than model fit statistics. These are mixed location heavy drinking (10.4% of occasions), heavy drinking at home with a partner (9.4%), going out with friends (11.1%), get‐together at someone's house (14.4%), going out for a meal (8.6%), drinking at home alone (13.6%), light drinking at home with family (12.8%) and light drinking at home with a partner (19.6%). Conclusions An empirical model of drinking culture, comprising a typology of drinking practices, reveals the dominance of moderate drinking practices in Great Britain. The model demonstrates the potential for a practice perspective to be used in evaluation of how and why drinking cultures change in response to public health interventions. PMID:27095617

  11. Prime Contract Awards Alphabetically by Contractor, State or Country, and Place. Part 14 (Picker International Inc, Aurora, Colorado - Roofing Systems Inc, Fort Lewis, Washington), FY1991

    DTIC Science & Technology

    1991-01-01

    34 -4 IM 4M C14 M-4c4< ta-4-4 go co to -4 -4-4-4 to 0) 4 -4-4 to (y) 0) 0) 4M 0) CIMM 4 W-4"< -4-4-4 -4-4 -4 Lr) NNN -4dn" c) m Cl) M M -. 4 on cv) N 00...X0 -4 0 -4 -4 N (0 N NN4-4 -4 -4N.4NN-I -44 NN’IN 4 . -4 -4 M-- NM 0 )))000))00000000 0) 0) 00) 0 N M ;:: ( N-4N" -4-NC’) CIMM ’ -4N2-NOO 4 04 N 0 0 N...471 ONNN4C 04 On~n 2009 -.41- 01- 04000)ONcl -I 4 16- 0-I If ɜ I-1 N4 CJ -4 044 -* we) LA r- 00 L)CO) N-4i~n W 6-46 10-1 If C 0 0 0 CO( 0000 0 D

  12. Dollar Summary of Prime Contract Awards by Contractor, State or Country, and Place. Part 2 (Bucher Willis RTLFF CNSLG-E & E Machine Service)

    DTIC Science & Technology

    1990-01-01

    4 ’-< 4m 0 0 < td .I 0. 00 N) 00-4 go- . .4 CA 8 4o63-U< - 40 "oi 0 1 I I4 8-.0 mg - m0 -4-4 06 8m a 4 - iM C 2 I .JI 0N0 0 08 -40 0 4(02-4 8-’- No1...o I Si It U) z z m m . zz z - A " c C cc < I Z 0 wo 0 0 0 3 cc I "U U -) 0 D 1-- 0 3x 0 w wc 0 n .I L C 0 I1 Iw CU)" """ "-0 ". EUq . 3.. . cc I. I...L L-> 00 ’N(( 1-4 td ’ >5T 00 -04( od 06 46 a s -1 4. -4 I aE I I S Wr I W6 4 IL z -I x- I I- a00 N L) < L W C 0 I I 1.- 0 I - I ccI- I 6 2 6 .J 011

  13. Department of Defense Prime Contracts over $25,000 for Research and Development. Fiscal Year 1992. (AB11 American Science & Engineering-AZ16 Wizdom Systems, Inc)

    DTIC Science & Technology

    1993-01-01

    0 21 0- td 0. 0. 0. m. =.0 0 0 . 0. Its 0 m 0. a.. m. qA _ q U1 14 U) 0l u) m) U) U ) U f ) U) U ) U ) ) U) >) U 1 1 a 0. Il-I- - - f0 1-11 mS UI La...4 -4 -4 1. 0 -41 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 24 0111ý I 1 0 0 0 0 0 0 00 0 0 1-0 0 0 0 t -1 i. 4 .4 ’.4 . .4_ -4 _ to 4 td 4 go4 td m. m...411 td do Ui 0A IA IA IA IA 0AU I A I A I A I A w US 0 nm ma . a. a. a. a. a. a. -. a. a. a. a 3.. . a. a. . F0- 0 -4 ýai ~ 4 . -4 9 .4 *- 4 m4 .4 .4

  14. Growth and composition of nanostructured and nanoporous cerium oxide thin films on a graphite foil.

    PubMed

    Lavkova, Jaroslava; Khalakhan, Ivan; Chundak, Mykhailo; Vorokhta, Mykhailo; Potin, Valerie; Matolin, Vladimir; Matolinova, Iva

    2015-03-07

    The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of the layers with different thicknesses performed by energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and X-ray photoelectron spectroscopy have pointed to the reduction of the cerium oxide layers. In the deposited layers, cerium was present in mixed Ce(3+) and Ce(4+) valence. Ce(3+) species were located mainly at the graphite foil-CeOx interface and the chemical state of cerium was gradually changing to Ce(4+) going to the layer surface. It became more stoichiometric in the case of thicker layers except for the surface region, where the presence of Ce(3+) was associated with oxygen vacancies on the surface of cerium oxide grains. The degree of cerium oxide reduction is discussed in the context of particle size.

  15. Antibacterial properties of amino acid functionalized silver nanoparticles decorated on graphene oxide sheets.

    PubMed

    Chandraker, Kumudini; Nagwanshi, Rekha; Jadhav, S K; Ghosh, Kallol K; Satnami, Manmohan L

    2017-03-16

    Graphene oxide (GO) sheets decorated with amino acid L-cysteine (L-cys) functionalized silver nanoparticles (GO-L-cys-Ag) was synthesized by AgNO3, trisodium citrate, and NaBH4. GO-L-cys-Ag nanocomposite was characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, which demonstrated that a diameter of L-cys-AgNPs compactly deposited on GO. Antibacterial activity tests of GO-L-cys-Ag nanocomposite were carried out using Escherichia coli MTCC 1687 and Staphylococcus aureus MTCC 3160 as model strains of Gram-negative and Gram-positive bacteria, respectively. The effect of bactericide dosage on antibacterial activity of GO-L-cys-Ag nanocomposite was examined by plate count, well diffusion and broth dilution methods. Morphological observation of bacterial cells by scanning electron microscope (SEM) showed that GO-L-cys-Ag nanocomposite was more destructive to cell membrane of Escherichia coli than that of Staphylococcus aureus. The above technique establish that the bactericidal property of GO-L-cys-Ag nanocomposite with wide range of applications in biomedical science.

  16. Communication: Studies of the Lennard-Jones fluid in 2, 3, and 4 dimensions highlight the need for a liquid-state 1/d expansion.

    PubMed

    Costigliola, Lorenzo; Schrøder, Thomas B; Dyre, Jeppe C

    2016-06-21

    The recent theoretical prediction by Maimbourg and Kurchan [e-print arXiv:1603.05023 (2016)] that for regular pair-potential systems the virial potential-energy correlation coefficient increases towards unity as the dimension d goes to infinity is investigated for the standard 12-6 Lennard-Jones fluid. This is done by computer simulations for d = 2, 3, 4 going from the critical point along the critical isotherm/isochore to higher density/temperature. In both cases the virial potential-energy correlation coefficient increases significantly. For a given density and temperature relative to the critical point, with increasing number of dimension the Lennard-Jones system conforms better to the hidden-scale-invariance property characterized by high virial potential-energy correlations (a property that leads to the existence of isomorphs in the thermodynamic phase diagram, implying that it becomes effectively one-dimensional in regard to structure and dynamics). The present paper also gives the first numerical demonstration of isomorph invariance of structure and dynamics in four dimensions. Our findings emphasize the need for a universally applicable 1/d expansion in liquid-state theory; we conjecture that the systems known to obey hidden scale invariance in three dimensions are those for which the yet-to-be-developed 1/d expansion converges rapidly.

  17. Fabricating a graphene oxide—bayberry tannin sponge for effective radionuclide removal

    NASA Astrophysics Data System (ADS)

    Deng, Xiaodong; Liu, Xiaonan; Duan, Tao; Zhu, Wenkun; Yi, Zao; Yao, Weitang

    2016-05-01

    Bayberry tannin (BT)-reduced graphene oxide (rGO) sponges have been prepared by self-assembly, with bayberry tannin serving as both reductant and surface functionalization agent. The synthetic method is based on the self-assembly of graphene oxide (GO) sheets into porous hydrogel structures. By varying the weight ratio of GO to BT, a series of sorbents with different densities of organic molecules have been obtained and applied to remove Sr2+ from aqueous solutions. Adsorption isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order and pseudo-second order) have been investigated to discuss the sorption performance of rGO/BT sponges. The rGO/BT (w/w 1:1) sponge shows excellent adsorption properties for Sr2+, with maximum capacities of 67.98 mg g-1. The adsorption capacity is much higher than those in classic Sr2+ adsorbents, such as hydrous manganese dioxide, Egyptian soils, Hydroxyapatite nanoparticles, sodium hexa-titanate nanofibers, Graphene oxide, artificially altered phlogopite(Ca-Phl), and PB/Fe3O4/GO. Adsorption mechanisms have been examined using the x-ray photoelectron spectra of sorbents before and after Sr2+ adsorption, and the results indicate that the sorption of Sr2+ on GO and GO/BT 1.0 is largely depended on oxygen functional groups. The results show that the GO/BT sponge is a promising candidate for adsorbing Sr2+ ion.

  18. Insights into electrode/electrolyte interfacial processes and the effect of nanostructured cobalt oxides loading on graphene-based hybrids by scanning electrochemical microscopy

    NASA Astrophysics Data System (ADS)

    Gupta, Sanju; Carrizosa, Sara B.

    2016-12-01

    Nanostructured cobalt oxide polymorphs (CoO and Co3O4) deposited via electrodeposition allowed optimal loading on supercapacitive graphene nanosheets producing a set of graphene-based hybrids namely, CoO/GO, CoO/ErGO, Co3O4/GO, Co3O4/rGO, and Co3O4/ErGO, as pseudocapacitive electrochemical electrodes. We gained fundamental insights into the complex physicochemical interfacial processes at electrode surfaces and electrode/electrolyte (or solid/liquid) interfaces by scanning electrochemical microscopy operating in the feedback probe approach and imaging modes while monitoring and mapping the redox probe (re)activity behavior. We determined the various experimental descriptors including diffusion coefficient, electron transfer rate, and electroactive site distribution on electrodes. We emphasize the interplay of (1) heterogeneous basal and edge plane active sites, (2) graphene surface functional moieties (conducting/semiconducting), and (3) crystalline spinel cobalt oxides (semiconducting/insulating) coated graphene, reinforcing the available electron density of states in the vicinity of the Fermi level contributing to higher electroactivity, faster interfacial diffusion, and shorter distances for electron transfer, facilitated through molecular and chemical bridges obtained by electrodeposition as compared with the physical deposition.

  19. Hybrid Iron Oxide-Graphene Oxide-Polysaccharides Microcapsule: A Micro-Matryoshka for On-Demand Drug Release and Antitumor Therapy In Vivo.

    PubMed

    Deng, Lin; Li, Qiujin; Al-Rehili, Safa'a; Omar, Haneen; Almalik, Abdulaziz; Alshamsan, Aws; Zhang, Jianfei; Khashab, Niveen M

    2016-03-23

    Premature drug release is a common drawback in stimuli-responsive drug delivery systems (DDS), especially if it depends on internal triggers, which are hard to control, or a single external stimulus, which can only have one function. Thus, many DDS systems have been reported that combined different triggers; however, limited success has been established in fine-tuning the release process, mainly due to the poor bioavailability and complexity of the reported designs. This paper reports the design of a hybrid microcapsule (h-MC) by a simple layer-by-layer technique comprising polysaccharides (sodium alginate, chitosan, and hyaluronic acid), iron oxide, and graphene oxide (GO). Electrostatic assembly of the oppositely charged polysaccharides and graphene sheets provided a robust structure in which to load drugs through pH control. The polysaccharide component ensured high biocompatibility, bioavailability, and tumor cells targeting. The alternative magnetic field and near-infrared laser triggerable Fe3O4@GO component provided for dual high-energy and high-penetration hyperthermia therapy. On-demand drug release from h-MC can be achieved by synchronizing these external triggers, making the release highly controllable. The synergistic effect of hyperthermia and chemotherapy was successfully confirmed in vitro and in vivo.

  20. Mesoporous composite nickel cobalt oxide/graphene oxide synthesized via a template-assistant co-precipitation route as electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Xu, Yanjie; Wang, Lincai; Cao, Peiqi; Cai, Chuanlin; Fu, Yanbao; Ma, Xiaohua

    2016-02-01

    A simple co-precipitation method utilizing SDS (sodium dodecyl sulfate) as template and ammonia as precipitant is successfully employed to synthesize nickel cobalt oxide/graphene oxide (NiCo2O4/GO) composite. The as-prepared composite (NCG-10) exhibits a high capacitance of 1211.25 F g-1, 687 F g-1 at the current density of 1 A g-1, 10 A g-1 and good cycling ability which renders NCG-10 as promising electrode material for supercapacitors. An asymmetric supercapacitor (ASC) (full button cell) has been constructed with NCG-10 as positive electrode and lab-made reduced graphene oxide (rGO) as negative electrode. The fabricated NCG-10//rGO with an extended stable operational voltage of 1.6 V can deliver a high specific capacitance of 144.45 F g-1 at a current density of 1 A g-1. The as-prepared NCG-10//rGO demonstrates remarkable energy density (51.36 W h kg-1 at 1 A g-1), high power density (50 kW kg-1 at 20 A g-1). The retention of capacitance is 88.6% at the current density of 8 A g-1 after 2000 cycles. The enhanced capacitive performance can be attributed to the improved specific surface area and 3D open area of NCG-10 generated by the pores and channels with the substantial function of SDS.

  1. Life goes on: the experiences of wives of multiply-deployed National Guard soldiers.

    PubMed

    Patzel, Brenda; McBride, Maryellen; Bunting, Judith; Anno, Tony

    2013-05-01

    Whether a service member is active duty or part of the National Guard, deployment of these service members is a major issue for most families. There is limited knowledge of the experience of multiple deployments on the family. The purpose of this study was to describe experiences of wives of National Guard soldiers that were deployed more than once. Nine wives were interviewed. An analysis of the interviews revealed four themes: (1) "Life Goes On" (i.e., despite the repeated deployments, life continues at home); (2) the "Guard is a Different Animal" (i.e., life as a National Guard spouse is different from that of an active duty spouse); (3) "It's a Mind-Set" (i.e., how wives cope their husband's deployment); and (4) "Going Back Again" (i.e., wives' experiences of multiple deployments). Exploring how multiple deployments affects wives of National Guard soldiers is helpful in understanding their experiences and the adjustments that must be made in family life. Knowledge of the experiences of these wives may help in formulating more effective interventions with families who have experienced multiple deployments.

  2. Complete genome sequences of pigeon adenovirus 1 and duck adenovirus 2 extend the number of species within the genus Aviadenovirus.

    PubMed

    Marek, Ana; Kaján, Győző L; Kosiol, Carolin; Harrach, Balázs; Schlötterer, Christian; Hess, Michael

    2014-08-01

    Complete genomes of the first isolates of pigeon adenovirus 1 (PiAdV-1) and Muscovy duck adenovirus (duck adenovirus 2, DAdV-2) were sequenced. The PiAdV-1 genome is 45,480bp long, and has a gene organization most similar to turkey adenovirus 1. Near the left end of the genome, it lacks ORF0, ORF1A, ORF1B and ORF1C, and possesses ORF52, whereas six novel genes were found near the right end. The DAdV-2 genome is 43,734bp long, and has a gene organization similar to that of goose adenovirus 4 (GoAdV-4). It lacks ORF51, ORF1C and ORF54, and possesses ORF55A and five other novel genes. PiAdV-1 and DAdV-2 genomes contain two and one fiber genes, respectively. Genome organization, G+C content, molecular phylogeny and host type confirm the need to establish two novel species (Pigeon aviadenovirus A and Duck aviadenovirus B) within the genus Aviadenovirus. Phylogenetic data show that DAdV-2 is most closely related to GoAdV-4.

  3. Comparative effectiveness of correction strategies in connected discourse tracking.

    PubMed

    Lunato, K E; Weisenberger, J M

    1994-10-01

    The effectiveness of four correction strategies commonly used in connected discourse tracking was investigated in the present study. The strategies were 1) verbatim repetition of a word or phrase; 2) use of antonyms or synonyms as cues; 3) use of phonemic cues, with no whole word repetition; and 4) going back or ahead in the text, with no repetition of the missed segment. Four normal-hearing adults served as listeners. Live-voice presentation of text by two female talkers was employed for all conditions. Listeners were tested in two stimulus presentation modes, speechreading alone and speechreading plus a multichannel tactile aid. Results indicated that strategy 1, repetition of the missed segment, produced the highest tracking rates, significantly higher than any of the other strategies. Strategy 2 produced the lowest tracking rates. Strategies 1 and 3 yielded the lowest percentage of initially missed words, or blockages, and strategy 4 the highest percentage. Significantly higher tracking rates were found under the speechreading plus tactile aid presentation mode, compared with speechreading alone. Further, tracking rates increased significantly from the beginning to the end of training. Data were compared with a more typical CDT task, in which all correction strategies were operative, and results showed little difference in tracking rates between this task and the constrained CDT employing only strategy 1. Overall, results suggest that simple repetition of missed segments is an effective correction strategy for CDT and argue for its inclusion in computer-assisted tracking implementations.

  4. Department of the Air Force Justification of Estimates for Fiscal Year 1982 Submitted to Congress January 1981.

    DTIC Science & Technology

    1981-01-01

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  5. Aerospace Physiology Career Ladder AFSC 911X0.

    DTIC Science & Technology

    1980-08-01

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  6. Department of the Army FY 1990/FY 1991 Biennial Budget Estimates Submitted to Congress January 1989. Operation and Maintenance, Army Databook, Volume 2

    DTIC Science & Technology

    1989-01-01

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  7. Prime Contract Awards of $100,000 or More by Federal Supply Classification of Service Category and Purchasing Office. Part 4 (H210-R709)

    DTIC Science & Technology

    1989-01-01

    cfl(33.N1 CL00))CC < .. 4 .. )0 c 7L-4<U))0 0 cc44ɛ 3:N,( oc9l(D,( D4 m QL: C) >.3 - w 0:CC wwUIUO Ix-X --- ... N)-C 0 . 0 0.)cv~n> <W u 02 mc ( 1.. c u...4LC 0 o rC -, .4 D4 ~ go&aj0.-i0 Eo . x L) =4-1 I. ~ 0 to E 0W LL.>IN1- >.N L = 0 0 -0 1 *..-D CL 𔃺 W(C.C .4 M CL CLO% 001..G S. JCJ ..- CCEO 0 (D W...c c< (AX 00 Eu C3 cc L- m d4 )EO U L)& L) - 0)-...u OO -4- Um.L -4--U. to cL 0 to a) 00..C14 1 .- Li- =)I O= 0 .’’-40- a 0~ ~ 0)0 l-. 0. C0. =UU r,10

  8. Covalently coupled hybrid of graphitic carbon nitride with reduced graphene oxide as a superior performance lithium-ion battery anode.

    PubMed

    Fu, Yongsheng; Zhu, Junwu; Hu, Chong; Wu, Xiaodong; Wang, Xin

    2014-11-07

    An in situ chemical synthetic approach has been designed for the fabrication of a covalently coupled hybrid consisting of graphitic carbon nitride (g-C3N4) with reduced graphene oxide (rGO) with differing g-C3N4/rGO ratio. The epoxy groups of graphene oxide (GO) undergo a nucleophilic substitution reaction with dicyandiamide (C2H4N4) to form the C2H4N4-GO composite via a covalent C-N bond, and then both the in situ polymerization of C2H4N4 and the thermal reduction of GO can be achieved at higher temperatures, forming the covalently coupled g-C3N4-rGO. FT-IR, CP-MAS NMR and XPS analyses, clearly revealed a covalent interaction between the g-C3N4 and rGO sheets. The g-C3N4-rGO exhibits an unprecedented high, stable and reversible capacity of 1525 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles. Even at a large current density of 1000 mA g(-1), a reversible capacity of 943 mA h g(-1) can still be retained. The superior electrochemical performance of g-C3N4-rGO is attributed to the specific characteristics of the unique nanostructure of g-C3N4-rGO and the concerted effects of g-C3N4 and rGO, including covalent interactions between the two moieties, the good conductivity and high special surface area of the nanocomposite, as well as the template effect of the planar amino group of g-C3N4 for the dispersed decoration of Li(+) ions.

  9. The Oral Intake of Organic Germanium, Ge-132, Elevates α-Tocopherol Levels in the Plas-ma and Modulates Hepatic Gene Expression Profiles to Promote Immune Activation in Mice.

    PubMed

    Nakamura, Takashi; Takeda, Tomoya; Tokuji, Yoshihiko

    2014-01-01

    The common water-soluble organic germanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) exhibits activities related to immune responses and antioxidant induction. In this study, we evaluated the antioxidative effect of dietary Ge-132 in the plasma of mice. Male ICR mice (seven mice per group) received an AIN-76 diet with 0.05% Ge-132; three groups received the Ge-132-containing diet for 0, 1 or 4 days. The plasma alpha-tocopherol (α-tocopherol) concentration increased from 6.85 to 9.60 μg/ml after 4 days of Ge-132 intake (p<0.05). We evaluated the changes in hepatic gene expression related to antioxidative activity as well as in the entire expression profile after one day of Ge-132 intake, using DNA microarray technology. We identified 1,220 genes with altered expression levels greater than 1.5-fold (increased or decreased) as a result of Ge-132 intake, and α-tocopherol transfer protein (Ttpa) gene expression was increased 1.62-fold. Immune activation was identified as the category with the most changes (containing 60 Gene Ontology (GO) term biological processes (BPs), 41 genes) via functional clustering analysis of altered gene expression. Ge-132 affected genes in clusters related to ATP production (22 GO term BPs, 21 genes), lipid metabolism (4 GO term BPs, 38 genes) and apoptosis (5 GO term BPs). Many GO term BPs containing these categories were significantly affected by the Ge-132 intake. Oral Ge-132 intake may therefore have increased plasma α-tocopherol levels by up-regulating α-tocopherol transfer protein (Ttpa) gene expression.

  10. Coextraction of acidic, basic and amphiprotic pollutants using multiwalled carbon nanotubes/magnetite nanoparticles@polypyrrole composite.

    PubMed

    Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira

    2015-09-18

    The simultaneous extraction of acidic, basic and amphiprotic pollutants from various samples is a considerable and disputable concept in sample preparation strategies. In this study, for the first time, coextraction of acidic, basic and amphiprotic pollutants (polar and apolar) with multiwalled carbon nanotubes/Fe3O4@polypyrrole (MWCNTs/Fe3O4@PPy) composite based dispersive micro-solid phase extraction followed by high performance liquid chromatography-photo diode array detection was introduced. Firstly, the extraction efficiency of various magnetic nanosorbents including Fe3O4, MWCNTs/Fe3O4, graphene oxide/Fe3O4 (GO/Fe3O4), Fe3O4@PPy, MWCNTs/Fe3O4@PPy and GO/Fe3O4@PPy were compared. The results revealed that MWCNTs/Fe3O4@PPy nanocomposite has higher extraction efficiency for five selected model analytes (4-nitrophenol, 3-nitroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline and 1-amino-2-naphthol). Box-Behnken design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. The opted conditions were: pH of the sample, 8.2; sorbent amount, 12 mg; sorption time, 5.5 min; salt concentration, 14% w/w; type and volume of the eluent, 120 μL acetonitrile; elution time; 2 min. Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.1-0.25 μg L(-1) and 0.5-600 μg L(-1), respectively. The percent of extraction recovery and relative standard deviations (n=5) were in the range of 45.6-82.2 and 4.0-8.5, respectively. Ultimately, the applicability of this method was successfully confirmed by analyzing rain, snow and river water samples and satisfactory results were obtained.

  11. Simple rules for making alliances work.

    PubMed

    Hughes, Jonathan; Weiss, Jeff

    2007-11-01

    Corporate alliances are growing in number--by about 25% a year--and account for up to a third of revenues and value at many companies. Yet some 60% to 70% of them fail. What is going wrong? Because alliances involve interdependence between companies that may be competitors and may also have vastly different operating styles and cultures, they demand more care and handling than other business arrangements, say Hughes and Weiss, management consultants at Vantage Partners. The authors have developed five principles--based on their two decades of work with alliances -to complement the conventional advice on alliance management: (1) Focus less on defining the business plan and more on how you and your partner will work together. (2) Develop metrics pegged not only to alliance goals but also to performance in working toward them. (3) Instead of trying to eliminate differences, leverage them to create value. (4) Go beyond formal systems and structures to enable and encourage collaborative behavior. (5) Be as diligent in managing your internal stakeholders as you are in managing the relationship with your partner. Companies that have adopted these principles have radically improved their alliance success rate. Schering-Plough, for example, engages in a systematic "alliance relationship launch": four to six weeks of meetings at which the partners explore potential challenges, examine key differences and develop shared protocols for managing them, and establish mechanisms for day-to-day decision making. Blue Cross and Blue Shield of Florida measures the quality of alliance progress through regular surveys of both its own staff and its partners'. These companies have learned that the conventional advice is not so much wrong as incomplete. The five simple rules can help fill in the blanks.

  12. Extension of the crosstalk cancellation method in ultrasonic transducer arrays from the harmonic regime to the transient one.

    PubMed

    Bybi, A; Grondel, S; Assaad, J; Hladky-Hennion, A-C

    2014-02-01

    This paper describes a procedure to extend the crosstalk correction method presented in a previous paper [A. Bybi, S. Grondel, J. Assaad, A.-C. Hladky-Hennion, M. Rguiti, Reducing crosstalk in array structures by controlling the excitation voltage of individual elements: a feasibility study, Ultrasonics, 53 (6) (2013) 1135-1140] from the harmonic regime to the transient one. For this purpose a part of an ultrasonic transducer array radiating in water is modeled around the frequency 0.5 MHz using the finite element method. The study is carried out at low frequency in order to respect the same operating conditions than the previous paper. This choice facilitated the fabrication of the transducer arrays and the comparison of the numerical results with the experimental ones. The modeled array is composed of seventeen elements with the central element excited, while the others are grounded. The matching layers and the backing are not taken into account which limits the crosstalk only to the piezoelectric elements and fluid. This consideration reduces the structure density mesh and results in faster computation time (about 25 min for each configuration using a computer with a processor Intel Core i5-3210M, frequency 2.5 GHz and having 4 Go memory (RAM)). The novelty of this research work is to prove the efficiency of the crosstalk correction method in large frequency band as it is the case in medical imaging. The numerical results show the validity of the approach and demonstrate that crosstalk can be reduced by at least 13 dB in terms of displacement. Consequently, the directivity pattern of the individual element can be improved.

  13. Preparation of graphene oxide/polyacrylamide composite hydrogel and its effect on Schwann cells attachment and proliferation.

    PubMed

    Li, Guicai; Zhao, Yinxin; Zhang, Luzhong; Gao, Ming; Kong, Yan; Yang, Yumin

    2016-07-01

    Various hydrogel materials have been developed for improving the regeneration of peripheral nerve. Among which the graphene related hydrogels with excellent mechanical properties have attracted great attention. However, the effect of these hydrogels on peripheral nerve regeneration is still unclear. In the present study, the graphene oxide/polyacrylamide (GO/PAM) composite hydrogels were fabricated by in-situ free radical polymerization. The morphology, wettability, composition, swelling ratio, mechanical property and degradation behavior of the prepared GO/PAM composite hydrogels were separately characterized. The effect of GO/PAM hydrogel on the attachment and proliferation of Schwann cells was evaluated. Moreover, the release of biofactors by Schwann cells and adsorption of matrix proteins were further measured. The results showed that the color of the hydrogel became darker with the increased GO concentration, while the surface pore structure also displayed large variation when GO concentration was increased. The hydrophobicity and mechanical properties of hydrogel were increased with the ascending GO concentration. In addition, the variation of GO concentration displayed no obvious influence on the degradation of the composite hydrogel in different medium. The GO/PAM composite hydrogel with 0.4% GO (G0.4) could effectively enhance the attachment and proliferation of Schwann cells. Furthermore, the cells on G0.4 hydrogel displayed higher biofactors release and larger matrix adsorption than other samples. The results demonstrated that GO with suitable concentration in PAM hydrogel could effectively promote Schwann cell growth. The study may provide an important experimental basis for the design and development of new nerve grafts with potential application for peripheral nerve regeneration.

  14. Comparison of teen and adult driver crash scenarios in a nationally representative sample of serious crashes.

    PubMed

    McDonald, Catherine C; Curry, Allison E; Kandadai, Venk; Sommers, Marilyn S; Winston, Flaura K

    2014-11-01

    Motor vehicle crashes are the leading cause of death and acquired disability during the first four decades of life. While teen drivers have the highest crash risk, few studies examine the similarities and differences in teen and adult driver crashes. We aimed to: (1) identify and compare the most frequent crash scenarios-integrated information on a vehicle's movement prior to crash, immediate pre-crash event, and crash configuration-for teen and adult drivers involved in serious crashes, and (2) for the most frequent scenarios, explore whether the distribution of driver critical errors differed for teens and adult drivers. We analyzed data from the National Motor Vehicle Crash Causation Survey, a nationally representative study of serious crashes conducted by the U.S. National Highway Traffic Safety Administration from 2005 to 2007. Our sample included 642 16- to 19-year-old and 1167 35- to 54-year-old crash-involved drivers (weighted n=296,482 and 439,356, respectively) who made a critical error that led to their crash's critical pre-crash event (i.e., event that made the crash inevitable). We estimated prevalence ratios (PR) and 95% confidence intervals (CI) to compare the relative frequency of crash scenarios and driver critical errors. The top five crash scenarios among teen drivers, accounting for 37.3% of their crashes, included: (1) going straight, other vehicle stopped, rear end; (2) stopped in traffic lane, turning left at intersection, turn into path of other vehicle; (3) negotiating curve, off right edge of road, right roadside departure; (4) going straight, off right edge of road, right roadside departure; and (5) stopped in lane, turning left at intersection, turn across path of other vehicle. The top five crash scenarios among adult drivers, accounting for 33.9% of their crashes, included the same scenarios as the teen drivers with the exception of scenario (3) and the addition of going straight, crossing over an intersection, and continuing on a

  15. Covalently coupled hybrid of graphitic carbon nitride with reduced graphene oxide as a superior performance lithium-ion battery anode

    NASA Astrophysics Data System (ADS)

    Fu, Yongsheng; Zhu, Junwu; Hu, Chong; Wu, Xiaodong; Wang, Xin

    2014-10-01

    An in situ chemical synthetic approach has been designed for the fabrication of a covalently coupled hybrid consisting of graphitic carbon nitride (g-C3N4) with reduced graphene oxide (rGO) with differing g-C3N4/rGO ratio. The epoxy groups of graphene oxide (GO) undergo a nucleophilic substitution reaction with dicyandiamide (C2H4N4) to form the C2H4N4-GO composite via a covalent C-N bond, and then both the in situ polymerization of C2H4N4 and the thermal reduction of GO can be achieved at higher temperatures, forming the covalently coupled g-C3N4-rGO. FT-IR, CP-MAS NMR and XPS analyses, clearly revealed a covalent interaction between the g-C3N4 and rGO sheets. The g-C3N4-rGO exhibits an unprecedented high, stable and reversible capacity of 1525 mA h g-1 at a current density of 100 mA g-1 after 50 cycles. Even at a large current density of 1000 mA g-1, a reversible capacity of 943 mA h g-1 can still be retained. The superior electrochemical performance of g-C3N4-rGO is attributed to the specific characteristics of the unique nanostructure of g-C3N4-rGO and the concerted effects of g-C3N4 and rGO, including covalent interactions between the two moieties, the good conductivity and high special surface area of the nanocomposite, as well as the template effect of the planar amino group of g-C3N4 for the dispersed decoration of Li+ ions.An in situ chemical synthetic approach has been designed for the fabrication of a covalently coupled hybrid consisting of graphitic carbon nitride (g-C3N4) with reduced graphene oxide (rGO) with differing g-C3N4/rGO ratio. The epoxy groups of graphene oxide (GO) undergo a nucleophilic substitution reaction with dicyandiamide (C2H4N4) to form the C2H4N4-GO composite via a covalent C-N bond, and then both the in situ polymerization of C2H4N4 and the thermal reduction of GO can be achieved at higher temperatures, forming the covalently coupled g-C3N4-rGO. FT-IR, CP-MAS NMR and XPS analyses, clearly revealed a covalent interaction between