Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Some characteristics for the analysis of non-conducting powders by direct current glow discharge atomic emission spectroscopy (dc-GD-AES) were investigated. Copper powder was chosen as a suitable host conducting material for the analysis of mixtures of rare earth oxides. The influences of sample preparation and discharge parameters on the sputtering rate, discharge stability and emission intensity of the analyte were investigated systematically. The sample-to-sample reproducibility was discussed, and the average RSDs were in the range from 4% to 5%. The proposed method was applied to the analysis of a mixture of rare earth oxides and the results obtained were in good agreement with those obtained by ICP-AES.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method of glow discharge atomic emission spectroscopy (GD-AES) is described for the determination of rare earth elements (REEs) after separation and preconcentration by micro-column packed with immobilized 1-phenyl-3-methyl-4-benzoyl-5-pyrazone (PMBP) on microcrystalline naphthalene. The graphite electrode with solution residue on its surface was used as a cathode. Various factors (the form of cathode, working condition) influencing the determination of the analytes were studied in detail. Under the experimental conditions selected, the detection limits for the determination of La, Nd, Eu, Dy and Y are 0.24, 0.32, 0.01, 0.07 and 0.06 μg/mL, respectively, with relative standard deviations (RSDs) in the range of 5–10%. The method was applied to determine La, Nd, Eu, Dy and Y in geological samples, and the analytical results are in good agreement with the reference values.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new method for the determination of trace amounts of 14 rare earth elements in high purity Y2O3 using fluorination assisted electrothermal vaporization inductively coupled plasma atomic emission spectrometry with slurry sampling was developed. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization of the analytes from graphite furnace. The main factors affecting analytical signals were investigated systematically. The interference of matrix could be minimized in the presence of PTFE. Under optimum conditions, the detection limits for rare earth elements were 0.032 ng∼2.52 ng and the relative standard deviations were in the range of 1.4% to 4.3%. The proposed method was applied to the direct analysis of high purity Y2O3 powder with satisfactory results.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-2242
    Keywords: Key words Oryza sativa L. ; AFLP markers ; RFLP markers ; Aluminum tolerance ; QTLs ; Epistasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  To investigate the genetic background for aluminum (Al) tolerance in rice, a recombinant inbred (RI) population, derived from a cross between an Al-sensitive lowland indica rice variety IR1552 and an Al-tolerant upland japonica rice variety Azucena, was used in culture solution. A molecular linkage map, together with 104 amplified fragment length polymorphism (AFLP) markers and 103 restriction fragment length polymorphism (RFLP) markers, was constructed to map quantitative trait loci (QTLs) and epistatic loci for Al tolerance based on the segregation for relative root length (RRL) in the population. RRL was measured after stress for 2 and 4 weeks at a concentration of 1mM of Al3+ and a control with a pH 4.0, respectively. Two QTLs were detected at both the 2nd and the 4th weeks on chromosomes 1 and 12 from unconditional mapping, while the QTL on chromosome 1 was only detected at the 2nd stress week from conditional mapping. The effect of the QTL on chromosome 12 was increased with an increase of the stress period from 2 to 4 weeks. The QTL on chromosome 1 was expressed only at the earlier stress, but its contribution to tolerance was prolonged during growth. At least one different QTL was detected at the different stress periods. Mean comparisons between marker genotypic classes indicated that the positive alleles at the QTLs were from the Al-tolerant upland rice Azucena. An important heterozygous non-allelic interaction on Al tolerance was found. The results indicated that tolerance in the younger seedlings was predominantly controlled by an additive effect, while an epistatic effect was more important to the tolerance in older seedlings; additionally the detected QTLs may be multiple allelic loci for Al tolerance and phosphorus-uptake efficiency, or for Al and Fe2+ tolerance.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-2218
    Keywords: Key words: Pneumoperitoneum, physiopathology — Laparoscopy, side effects — Locoregional therapy — Technology, medical
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Multimodal therapy is used increasingly in advanced gastrointestinal tumors. Potential benefits of using an intraoperative adjuvant therapy during laparoscopy for cancer have been documented in animal studies. The aim of this study was to develop a device that could deliver such an intraoperative drug therapy. Methods: We developed a micropump suitable for minimally invasive surgery procedures that allowed microdroplets of therapeutic substance to be distributed into the pneumoperitoneum (CO2), creating a ``therapeutic pneumoperitoneum.'' A closed-loop control system regulates drug delivery according to the gas flow. In vitro, the micropump is able to aerosolize various aqueous and ethanol solutions, including cytostatic and bacteriostatic drugs and adhesion-modulating agents. The size of the microdroplets has been optimized to prevent visual artifacts. Results: The micropump was tested in an animal model (pig). The system was inserted into a 5-mm trocar. After insufflation of a 12-mm CO2 pneumoperitoneum, laparoscopic sigmoid colon resections could be performed with no special difficulties. No fog developed, and no system-related complication was observed. At autopsy, the active principle was distributed to all exposed peritoneal surfaces. Conclusions: As opposed to conventional peritoneal washing, therapeutic pneumoperitoneum reaches the entire peritoneal surface, allowing an optimal drug distribution. Drug diffusion into the tissues is enhanced by the intraperitoneal pressure. Precise determination of the instantaneous and total drug quantity is possible. Therefore, this drug delivery system has several advantages over conventional irrigation. Its potential domains of application are locoregional cancer therapy, prevention of port-site recurrences, immunomodulation, analgesia, peritonitis, and prevention of postoperative adhesions.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aims:  To assess the usefulness of immunohistochemistry in delineating tumour diagnoses on a series of morphologically diagnosed renal spindle cell tumours (RSCTs).Methods and results:  Formalin-fixed paraffin-embedded tissues from 31 morphologically diagnosed tumours were reinterpreted in light of newly obtained immunohistochemical information. By morphology, six had originally been classified as sarcomatoid carcinoma, five as spindle cell tumour (NOS), four as sarcoma (NOS), three as leiomyoma, three as leiomyosarcoma, and one each as fibrous polyp, hamartoma, neurilemmoma, mesoblastic nephroma, medullary fibroma, angiomyolipoma, haemangiopericytoma, malignant rhabdoid tumour, malignant Triton tumour, and carcinosarcoma. The application of immunohistochemistry verified the original diagnosis in 18 cases (18/31, 58%), confirming the diagnosis of sarcomatoid renal carcinoma (4/6), leiomyoma (2/3), leiomyosarcoma (3/3), sarcoma (NOS) (2/4), carcinosarcoma (1/1), malignant rhabdoid tumour (1/1), malignant Triton tumour (1/1), fibrous polyp (1/1), mesoblastic nephroma (1/1), hamartoma (1/1), and angiomyolipoma (1/1). Different tumour designations were suggested in 13 cases (13/31, 42%), including carcinosarcoma, sarcoma (NOS), leiomyosarcoma, solitary fibrous tumour, monomorphic/biphasic angiomyolipoma, endometrial stromal tumour, and congenital mesoblastic nephroma.Conclusions:  Our data indicate that although morphology is most important in formulating the initial differential diagnosis, the addition of immunohistochemistry is vital in arriving at the correct classification of RSCTs.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From calculations of the variance, or the fluctuations, and the mean energy densityof a massless scalar field in the Minkowski vacuum as a function of an intrinsicscale defined by the world function between two nearby points (as used in pointseparation regularization), we show that, contrary to prior claims, the ratio ofvariance to its mean squared being of the order unity does not imply a failureof semiclassical gravity. It is more a consequence of the quantum nature of thestate of the matter field than any inadequacy of the theory of spacetime withquantum matter as source.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 3127-3129 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A template-synthesis technique based on self-ordered hexagonal nanopore alumina templates was applied to synthesize highly ordered carbon nanotube arrays via thermal decomposition of ethylene with iron as the catalyst electrodeposited into the bottom of the pores. The resultant carbon nanotubes are monodispersed and have open ends with uniform sizes. It was found that the insulating oxide layer lying between the carbon nanotubes and the underlying aluminum greatly obstructs the electron emission from the carbon nanotube arrays. After the oxide layer was removed, the arrays exhibited excellent field emission properties with a threshold electric field of ∼2.8 V/μm and emission current density of 0.08 mA/cm2 at 3.6 V/μm. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 1116-1124 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The presence of a strong magnetic field intrinsically changes the orbit of electrons in their Coulomb interactions with ions for a range of parameters. The characteristic scale for the orbit modification is r0=(Zme/4πε0B2)1/3 where Ze is the ion charge, me the electron mass, and B the magnetic field strength. The scale length is comparable to the interparticle spacing when ne1/3r0=(ωpe/ωce)2/3(Z/4π)1/3∼1 where ωpe/ωce are the electron plasma and cyclotron frequencies, respectively. For large angle scattering events we show complex chaotic scattering interaction events for low-energy electrons. The scattering angle has a fractal dependence on the impact parameter in the chaotic scattering intervals. The process is thought to be important in strongly magnetized, low-temperature plasmas, but the overall macroscopic effects remain to be determined. Test particle simulations are presented that show probability distributions are required to describe the outgoing states of the events with fixed impact parameter and energy which specify a unique Rutherford scattering angle. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 92 (2002), S. 1062-1064 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Monoclinic Ga2O3 nanobelts and nanosheets are obtained by a simple chemical route involved with H2O at 950 °C in Ar atmosphere. Electron microscopy observations reveal that the as-synthesized Ga2O3 nanobelts and nanosheets are structurally uniform, single crystalline, and most of them are free of defects and dislocations. The nanobelts are growing along with [001] facets, and the nanosheets are stacked up by (011) facets. The Raman scattering spectrum of Ga2O3 nanostructures shows a 30 cm−1 redshift at high wave numbers in comparison with that of bulk Ga2O3 powder. The photoluminescence spectrum reveals that there exists a stable blue emission band centered at 460 nm, which is mainly attributed to the oxygen vacancies in the Ga2O3 nanostructures. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...