Restoration of Sensitivity in Chemo

Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. Despite multimodal treatments including surgery, chemotherapy and radiotherapy the prognosis remains poor and relapse occurs regularly. The alkylating agent temozolomide (TMZ) has been shown to improve the overall survival in patients with malignant gliomas, especially in tumors with methylated promoter of the O6-methylguanine-DNA-methyltransferase (MGMT) gene. However, intrinsic and acquired resistance towards TMZ makes it crucial to find new therapeutic strategies aimed at improving the prognosis of patients suffering from malignant gliomas. Cold atmospheric plasma is a new auspicious candidate in cancer treatment. In the present study we demonstrate the anti-cancer properties of different dosages of cold atmospheric plasma (CAP) both in TMZ-sensitive and TMZ-resistant cells by proliferation assay, immunoblotting, cell cycle analysis, and clonogenicity assay. Importantly, CAP treatment restored the responsiveness of resistant glioma cells towards TMZ therapy. Concomitant treatment with CAP and TMZ led to inhibition of cell growth and cell cycle arrest, thus CAP might be a promising candidate for combination therapy especially for patients suffering from GBMs showing an unfavorable MGMT status and TMZ resistance

Analyzing human errors in flight mission operations

A long-term program is in progress at JPL to reduce cost and risk of flight mission operations through a defect prevention/error management program. The main thrust of this program is to create an environment in which the performance of the total system, both the human operator and the computer system, is optimized. To this end, 1580 Incident Surprise Anomaly reports (ISA's) from 1977-1991 were analyzed from the Voyager and Magellan projects. A Pareto analysis revealed that 38 percent of the errors were classified as human errors. A preliminary cluster analysis based on the Magellan human errors (204 ISA's) is presented here. The resulting clusters described the underlying relationships among the ISA's. Initial models of human error in flight mission operations are presented. Next, the Voyager ISA's will be scored and included in the analysis. Eventually, these relationships will be used to derive a theoretically motivated and empirically validated model of human error in flight mission operations. Ultimately, this analysis will be used to make continuous process improvements continuous process improvements to end-user applications and training requirements. This Total Quality Management approach will enable the management and prevention of errors in the future

A LEED structural analysis of the Co(100) surface

The structure of the clean Co(1010) surface has been analysed by LEED. Application of a recently developed computational scheme reveals the prevalence of the termination A in which the two topmost layers exhibit a narrow spacing of 0.62 Å, corresponding to a 12.8(±0.5)% contraction with respect to the bulk value, while the spacing between the second and third layer is slightly expanded by 0.8(±0.2)%

Improved methodologies for breeding striga-resistant sorghums

Parasitic flowering weeds of the genus Striga (Scrophulariaceae) cause substantial losses in sorghum [Sorghum bicolor (L.) Moench] production in sub-Saharan Africa. Striga-resistant sorghum cultivars could be a major component of integrated striga management, if resistance was available in adapted, productive germplasm. In this paper we review methodologies for breeding striga-resistant sorghums. The agar-gel assay is an excellent tool to screen host genotypes in the laboratory for low production of the striga seed germination stimulant. Further laboratory assays are needed which allow the non-destructive, rapid and inexpensive evaluation of individual plants for additional resistance mechanisms. Field screening for striga resistance is hampered by high microvariability in African soils, heterogeneity of natural infestations, and concomitant large environmental effects on striga emergence. An improved field testing methodology should include one or several of the following practices: field inoculation with striga seeds; appropriate experimental design including elevated replication number; specific plot layout; use of appropriate susceptible and resistant checks; evaluation in adjacent infested and uninfested plots; and the use of selection indices derived from emerged striga counts, striga vigor, and grain yield or a host plant damage score. Due to the extreme variability of the parasite and significant genotype×environment interaction effects, multi-locational screening is recommended to obtain materials with stable performance. Additional strategies include: careful definition of the target environments; determination of the most important selection traits in each target environment; characterization of crop germplasm and improvement of available sources of resistance for better agronomic performance; transfer and pyramiding of resistance genes into adapted, farmer-selected cultivars; development of striga-resistant parent lines for hybrid or synthetic cultivars; and development of random-mating populations with multiple sources of resistance. The development of marker-assisted selection techniques for broad-based, polygenic striga resistance is underway. This approach is particularly promising because striga resistance tests are difficult, expensive, and sometimes unreliable; the parasite is quarantined; and some resistance genes are recessive. Transgenic, herbicide-tolerant sorghums could contribute to an immediate, cost-effective control of striga by herbicides, but such cultivars are not yet available. The selection of sorghum cultivars with specific adaptation to integrated striga management approaches could contribute to sustainable sorghum production in striga-infested areas of sub-Saharan Afric

Selection of diazotrophic bacterial communities in biological sand filter mesocosms used for the treatment of phenolic-laden wastewater

Agri effluents such as winery or olive mill waste-waters are characterized by high phenolic concentrations. These compounds are highly toxic and generally refractory to biodegradation. Biological sand filters (BSFs) represent inexpensive, environmentally friendly, and sustainable wastewater treatment systems which rely vastly on microbial catabolic processes. Using denaturing gradient gel electrophoresis and terminal-restriction fragment length polymorphism, this study aimed to assess the impact of increasing concentrations of synthetic phenolic-rich wastewater, ranging from 96 mg L−1 gallic acid and138 mg L−1 vanillin (i.e., a total chemical oxygen demand (COD) of 234 mg L−1) to 2,400mg L−1 gallic acid and 3,442 mg L−1 vanillin (5,842 mg COD L−1), on bacterialcommunities and the specific functional diazotrophic community from BSF mesocosms. This amendment procedure instigated efficient BSF phenolic removal, significant modifications of the bacterial communities, and notably led to the selection of a phenolic-resistant and less diverse diazotrophic community. This suggests that bioavailable N is crucial in the functioning of biological treatment processes involving microbial communities, and thus that functional alterations in the bacterial communities in BSFs ensure provision of sufficient bioavailable nitrogen for the degradation of wastewater with a high C/N ratio.Web of Scienc

Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

The determination of phosphorus by graphite furnace atomic absorption spectrometry at the non-resonance line at 213.6 nm, and the capability of Zeeman-effect background correction (Z-BC) to deal with the fine-structured background absorption due to the PO molecule have been investigated in the presence of selected chemical modifiers. Two line source atomic absorption spectrometers, one with a longitudinally heated and the other with a transversely heated graphite tube atomizer have been used in this study, as well as two prototype high-resolution continuum source atomic absorption spectrometers, one of which had a longitudinally arranged magnet at the furnace. It has been found that Z-BC is capable correcting very well the background caused by the PO molecule, and also that of the NO molecule, which has been encountered when the Pd + Ca mixed modifier was used. Both spectra exhibited some Zeeman splitting, which, however, did not cause any artifacts or correction errors. The practical significance of this study is to confirm that accurate results can be obtained for the determination of phosphorus using Z-BC. The best sensitivity with a characteristic mass of m(0) = 11 ng P has been obtained with the pure Pd modifier, which also caused the lowest background level. The characteristic mass obtained with the mixed Pd + Ca modifier depended on the equipment used and was between m(0) = 9 ng P and m(0) = 15 ng P, and the background signal was higher. The major problem of Z-BC remains the relatively restricted linear working range

Enhancement of Anisotropy due to Fluctuations in Quasi-One-Dimensional Antiferromagnets

It is shown that the observed anisotropy of magnetization at high magnetic fields in RbMnBr3 , a quasi-one-dimensional antiferromagnet on a distorted stacked triangular lattice, is due to quantum and thermal fluctuations. These fluctuations are taken into account in the framework of linear spin-wave theory in the region of strong magnetic fields. In this region the divergent one-dimensional integrals are cut off by magnetic field and the bare easy-plane anisotropy. Logarithmical dependence on the cutoff leads to the "enhancement" of the anisotropy in magnetization. Comparison between magnetization data and our theory with parameters obtained from neutron scattering experiments has been done.Comment: 15 pages + 5 postscript figures available upon request, RevTex

Quasi-1D spin-1/2 Heisenberg magnets in their ordered phase: correlation functions

We study weakly coupled antiferromagnetic spin chains in their ordered phase by combinining an exact solution of the single-chain problem with an RPA analysis of the interchain interaction. A single chain is described by a quantum Sine-Gordon model and dynamical staggered susceptibilities are determined by employing the formfactor approach to quantum correlation functions. We consider both antiferromagnetic order encountered in quasi-1D materials like $KCuF_3$ and spin-Peierls order as found in $CuGeO_3$.Comment: 16 pages of revtex, 12 figure

VUV Photoionization Cross Sections of HO_2, H_2O_2, and H_2CO

The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO_2), hydrogen peroxide (H_2O_2), and formaldehyde (H_2CO) have been measured from their first ionization thresholds to 12.008 eV. HO_2, H_2O_2, and H_2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl_2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO_2, H_2O_2, and H_2CO on an absolute scale, resulting in absolute photoionization spectra

Determination of sulfur in biological samples using high-resolution molecular absorption spectrometry in a graphite furnace with direct solid sampling

The determination of sulfur in biological materials using high-resolution continuum source molecular absorption spectrometry and electrothermal vaporization of the carbon monosulfide (CS) molecule has been investigated in detail using direct solid sampling. Best results have been obtained coating the platform with tungsten as a permanent modifier, adding 40 mg Pd in solution as a chemical modifier, and the only sulfur compound that showed sufficient sensitivity and thermal stability to be used for calibration purposes under the conditions established for biological materials was thiourea. A pyrolysis temperature of at least 900 C could be used and the optimum vaporization temperature was 2500 C. Under optimized conditions a limit of detection of 0.015 mg S absolute or 0.03 mg g À1 S in the solid sample, based on a sample mass of 0.5 mg could be obtained; the characteristic mass was m 0 ¼ 18 ng. Five certified biological reference materials have been analyzed using direct solid sampling and calibration against aqueous standards; the results were in agreement with the certified values on a 95% confidence interval