Pre-irradiation with low-dose <Superscript>12</Superscript>C<Superscript>6+</Superscript> beam significantly enhances the efficacy of <Emphasis Type="Italic">AdCMV-p53</Emphasis> gene therapy in human non-small lung cancer

The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOl of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6 beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6 beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6 beam significantly improved cell to apoptosis. RBEs for the 12C6 AdCMV-p53 infection groups were 30%-60%, 20% -130% and 30%-70% more than those for the 12C6 -irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6 beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.     

Inclusive and exclusive measurements of high energy γ-rays in the 101 MeV <Superscript>19</Superscript>F +<Superscript>181</Superscript>Ta fusion reaction

The high energy γ-rays from the fusion-evaporation reaction 101 MeV ¹⁹F +¹⁸¹Ta have been measured in coincidence with different γ-ray fold windows or discrete γ-rays in final residual nuclei. The line-shape analysis of the high energy γ-ray spectra confirms the large deformation of the ²⁰⁰Pb nuclei at high angular momenta. Coincidences with discrete γ-transitions evidence a strong correlation between γ-rays in the Giant Dipole Resonance region (E_γ≥ 8 MeV) and final evaporation residues. Received: 14 September 1999 / Revised version: 17 December 1999     

Characteristics of high energy interactions I. High energy gamma-ray spectra near the top of the atmosphere

An emulsion chamber was used to study the characteristics of high energy nuclear interactions from the production spectra ofγ-rays. The emulsion chamber, which comprised of two parts, namely the detector and the graphite producer unit, was exposed to cosmic rays for about 7 hr at an atmospheric depth of 10 g cm⁻² at Hyderabad (geomagnetic latitude 7·6°N). 720 electromagnetic cascades due toγ-rays were recorded in the detector. These cascades were classified into three groups; (a)γ-rays from nuclear interactions in the detector (b)γ-rays from nuclear interactions in the producer unit and (c)γ-rays of atmospheric origin. The energies of the cascades were determined using photometric method. The spectra ofγ-rays from groups (a) and (c) were determined and compared with similar spectra obtained at greater atmospheric depths. The spectra were found to obey a power law. The spectrum ofγ-rays of atmospheric origin was found to steepen at high energies,E _r>2200 GeV.     

Plasmid DNA damage by heavy ions at spread-out Bragg peak energies

Interaction of ionizing radiation with plasmid DNA can lead to formation of single strand breaks, double strand breaks and clustered lesions. We have investigated the response of the synthetic plasmid pBR322 in aqueous solution upon irradiation with ¹²C ions under spread-out Bragg peak conditions (densely ionizing) and with ¹³⁷Cs γ-photons (sparsely ionizing) as a function of dose. To evaluate the relevance of indirect effects, i.e. influences of diffusion limited radical induced DNA damage triggered by water radiolysis, the experiments were performed at various concentrations of the radical scavenger mannitol. Agarose gel electrophoresis was employed to quantify the DNA damage. At low scavenger concentration for a given dose DNA damage is higher for γ-photons than for ¹²C. For the latter, the microscopic dose distribution is inhomogeneous, with very high dose deposited along the few tracks through the solution. This is in agreement with the concept that scavengers efficiently reduce damage for γ-photons, implying that the underlying damage mechanism is single strand break induction by OH radicals. For ¹²C induced damage, the fraction of SSB and DSB that is unaffected by radical scavengers and thus due to direct effect is quantified.     

Pre-equilibrium dipole excitation and γ-ray fragment angular correlation in the 32S +74Ge reaction

We report on the results obtained from the study of the ³²S +⁷⁴Ge deep inelastic reaction at incident energy E= 320 MeV. High-energy γ-rays were detected in an array of 6 seven-pack BaF₂ clusters. Coincidence with complex fragments detected in 12 three-stage telescopes ensured the selection of peripheral reaction events. In order to investigate the pre-equilibrium dipole strength excitation two independent analyses were performed. In the first analysis the energy spectra of the γ-rays were evaluated in the statistical model framework while in the second one the γ-ray fragment angular correlation with respect to the nuclear spin vector of the composite system was studied. Both methods indicate the excitation of dipole strength in the highly deformed dinucleus and provide dipole resonance parameter sets that are in good agreement with each other. Received: 24 March 1999 / Revised version: 17 May 1999     

Nucleation efficiency of R134a as a sensitive liquid for superheated drop emulsion detector

Superheated emulsion detector is known to detect neutrons, γ-rays and other charged particles. The present work includes the study of nucleation efficiency of superheated drops of one of the CFC-free liquids, R134a (C₂H₂F₄), to fast neutrons, its response to γ-rays from ²⁴¹Am and ¹³⁷Cs and compare its nucleation efficiency with that of R12. The observation indicates that because of the presence of hydrogen, the nucleation efficiency is less in R134a than in R12 in the present neutron energy range of consideration. R134a is one of the most environment-friendly, commercially available liquid that is suitable for superheated drop detector, specially in neutron dosimetry and one needs to investigate it in detail.     

γ -ray spectroscopy study of 11 ΛB and 12 ΛC

In this paper, a preliminary result from the latest hypernuclear γ -ray spectroscopy experiment (KEK-E566) is presented together with a short discussion. The experiment was performed at the KEK-PS K6 beam line in 2005. In this experiment, the ¹²C(π⁺, K ⁺)¹² _ΛC reaction was employed to populate ¹² _ΛC/¹¹ _ΛB hypernuclei. A germanium detector array, Hyperball2, was constructed to detect γ -rays emitted from the hypernuclei produced. Three hypernuclear γ -ray peaks were observed and assigned.     

Conversion electron measurements of 152Nd

Abstact: Multipolarities of γ-rays in ¹⁵²Nd have been studied by conversion electron measurements in the β⁻ decay of ¹⁵²Pr. The praseodymium activities were obtained by the thermal neutron fission of ²³⁵U and followed with the on-line isotope separator KUR–ISOL. Conversion electrons and γ-rays were measured with a Si(Li) detector and a HPGe detector, respectively. The two γ-rays, 226 keV and 285 keV, were decided to have the multipolarities of the E1 transition. The spins and parities of the 1600 keV and 1542 keV levels were determined to be 3⁺ and 2⁺, respectively. Received: 14 April 1998     

A new measurement of 208Tl levels

A new determination for the levels of the nucleus ²⁰⁸Tl was performed by measuring the γ-rays following the β^--decay of ²⁰⁸Hg. Twenty-six γ-rays were assigned and three new levels of ²⁰⁸Tl at 1.728 MeV, 1.652 MeV and 1.362 MeV have been affirmed. A partial ²⁰⁸Hg decaying γ scheme was proposed. The experimental level structure was compared with a shell model calculation. Received: 12 August 2002 / Accepted: 19 December 2002 / Published online: 25 February 2003 RID="a" ID="a"e-mail: Li41zhang@yahoo.com Communicated by W. Henning     

Evolution of shapes in 59Cu

High-spin states in ⁵⁹Cu were populated using the fusion-evaporation reaction ²⁸Si + ⁴⁰Ca at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4π charged-particle detector array Microball allowed for the detection of γ-rays in coincidence with evaporated light particles. The resulting extensive high-spin decay scheme of ⁵⁹Cu is presented, which comprises more than 320 γ-ray transitions connecting about 150 excited states. Their spins and parities have been assigned via directional correlations of γ-rays emitted from oriented states. Average quadrupole moments of rotational bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach. Received: 15 February 2002 / Accepted: 23 April 2002     

New states and γ-transitions in 209Bi observed in the (3He, d*γγ)-subcoulomb-reaction

High-spin states in ¹⁴³Pm have been investigated via the ¹²⁸Te(¹⁹F,4nγ)¹⁴³Pm reaction using techniques of in-beam γ-spectroscopy. γ-ray singles, γ-γ coincidences, γ-ray anisotropies and DCO ratios have been measured. Based on these measurements, the level scheme of ¹⁴³Pm has been extended up to an excitation energy of 10535.4 keV, including 48 new γ-rays deexciting 28 new levels. The yrast levels in ¹⁴³Pm can be understood qualitatively in the framework of a weak-coupling model. Received: 10 July 2000 / Accepted: 12 October 2000     

Beta-gamma-gamma directional correlation in103Rh

β-γ-γ directional correlation studies for the cascades (i)β-rays ofE _max=0.12 MeV,γ-rays of 557 keV andγ-rays of 53 keV and (ii)β-rays ofE _max=0.21 MeV,γ-rays of 444 keV andγ-rays of 53 keV have been made. The triple correlation functionsW(θ) were obtained to beW(θ)=1+(−0.153±0.031)P ₂(cosθ)+(0.004±0.035)P ₄(cosθ) forβ-rays ofE _max 0.12 MeV→557→53 keV cascade andW(θ)=1+(0.163±0.042)P ₂(cosθ)+(−0.035±0.058)P ₄(cosθ) forβ rays ofE _max=0.21 MeV→444 keV→53 keV cascade. Spins and parities of the 650, 537 and 93 keV levels of¹⁰³Rh are deduced by triple angular correlation and the internal conversion coefficient studies. Multipolarities of the transitions are also determined.     

First measurement of β-decay properties of the proton drip-line nucleus 60Ga

By using the fusion-evaporation reaction ²⁸Si(³⁶Ar,p3n) and spectroscopy of β-delayed γ-rays and charged particles on mass-separated sources, β-decay properties of the neutron-deficient isotope ⁶⁰Ga were studied for the first time. The half-life of ⁶⁰Ga was determined to be 70(15) ms, and, based on βγγ coincidences, the isobaric-analogue state in ⁶⁰Zn was identified at 4851.9(7) keV. A semiempirical proton separation energy value of 40(70) keV was deduced for ⁶⁰Ga. The experimental results on half-life, mass excess, proton separation energy, and structure of the ⁶⁰Zn daughter states are discussed in comparison with various model predictions, including large-scale shell model calculations. Received: 4 September 2001 / Accepted: 12 November 2001     

Study of very neutron deficient nuclei 178Pt and 181Au

The ¹⁷⁸Pt and ¹⁸¹Au nuclei have been studied with the (230 MeV) ⁴⁶Ti +¹⁴²Nd fusion-evaporation reaction; γ-rays, evaporated particles and recoiling nuclei have been detected by the γ-array GASP + the Si ball ISIS + the recoil mass spectrometer RMS. The newly observed structures in ¹⁷⁸Pt and ¹⁸¹Au are most probably built on the proton and quasi-proton h_9/2 and i_13/2 configurations. Received: 2 January 1998 / Revised version: 27 May 1998     

Improvement of S/N ratio of a proportional counter for depth selective conversion electron Mössbauer spectroscopy

The S/N ratio of a proportional counter for DCEMS of⁵⁷Fe was improved by introducing a lead slit which collimates incident γ-rays to hit only a sample. The background spectrum due to the 122 and 136 keV γ-rays was obtained and it was found that the fraction of the background noise of these γ-rays was 65% in the energy region of 2–5 keV. The S/N ratio for a natural iron foil was in good agreement with the calculated one.     

Parity of the band head at 3710 keV in 99Rh using clover detector as compton polarimeter

Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386 to 1368 ke V. The E1 multipolarity of the 1117 keV transition in ⁹⁹Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at 3710 keV in ⁹⁹Rh.     

不同LET射线对细胞的生物学效应

以人肝癌细胞系和正常肝细胞系为材料,报道了不同传能线密度射线辐射引发细胞染色体原初断裂及24 h内的修复情况。 计算了相对生物学效应的值。 以L02染色体总断裂数量得出的RBE值96.05 keV/μm的12C6+ 为3.6, 512 keV/μm 36Ar18+ 为2.9。 而以7721染色体总断裂数量得出的RBE值: 96.05 keV/μm的12C6+ 为3.5,512keV/μm 36Ar18+也为2.9。用产生等点染色单体断裂计算,则RBE更高。对比得出,高LET对增加等点染色单体断裂量的作用要远远大于对增加染色单体断裂量的作用。等点染色单体的断裂修复难度要远远大于染色单体断裂的修复难度, 这也是高LET高致死率的一个重要原因。 Human hepatoma SMMC 7721 and normal liver L02 cells were irradiated with γ rays,12C6+ and 36Ar18+ ion beams at the Heavy Ion Research Facility in Lanzhou(HIRFL). We reported the kinetic repair of chromosome breaks of L02 and SMMC 7721 cells in 24 h of post irradiation time. The relative biological effectiveness(RBE) for inducing chromatid breaks were 3.6 for L02 and 3.5 for SMMC 7721 cell lines at the linear energy transfer(LET) peak of 96.55 keV/μm 12C6+ ions, and 2.9 (both of the two cell lines) at 512 keV/μm 36Ar18+ ions.It suggested that the RBE of isochromatid type breaks induced by 36Ar18+ was higher than those by 12C6+. We concluded that the high production of isochromatid type breaks, induced by the densely ionizing track structure, could be regarded as a signature of high LET radiation exposure.     

Subthreshold and near threshold K+ meson photoproduction\newline on nuclei

The inclusive K⁺ meson production in photon–induced reactions in the near threshold and subthreshold energy regimes is analyzed with respect to the one–step (γN→K ⁺ Y, Y=Λ,Σ) incoherent production processes on the basis of an appropriate new folding model, which takes properly into account the struck target nucleon removal energy and internal momentum distribution (nucleon spectral function), extracted from recent quasielastic electron scattering experiments and from many–body calculations with realistic models of the NN interaction. Simple parametrizations for the total and differential cross sections of the K⁺ production in photon–nucleon collisions are presented. Comparison of the model calculations of the K⁺ differential cross sections for the reaction γ+C¹² in the threshold region with the existing experimental data is given, that displays the contributions to the K⁺ production at considered incident energies coming from the use of the single–particle part as well as high momentum and high removal energy part of the nucleon spectral function. Detailed predictions for the K⁺ total and differential cross sections from γH², γC¹² and γPb²⁰⁸ reactions at subthreshold and near threshold energies are provided. The influence of the uncertainties in the elementary K⁺ production cross sections on the K⁺ yield is explored. Received: 12 April 1999 / Revised version: 11 September 1999     

Free radicals in irradiated wheat flour detected by electron spin resonance

By electron spin resonance (ESR) spectroscopy, we revealed free radicals in wheat flour before and after γ-ray inrradiation and their thermal behavior during heat treatment. The ESR spectrum of wheat flour before irradiation consists of a sextet centered atg=2.0 and a singlet signal at the sameg-value position. The first one is attributable to a signal with hyperfine (hf) interactions of Mn²⁺ ion (hf constant, 7.4 mT). The second signal originates from the carbon-centered radical. Upon γ-ray irradiation, however, a new signal with two triplet lines at the low- and high-field ends was detected on the Mn²⁺ sextet lines. We analyzed the triplet ESR lines as due to powder spectra (rhombicg-tensor symmetry) with nitrogen (¹⁴N) hf interactions. This indicates that a new organic radical was induced in the conjugated protein portion of wheat flour by γ-ray irradiation. The intensity of the organic free radical atg=2.0 detected in irradiated wheat flour increased monotonically under thermal treatment. The analysis of the time-dependent evolution process on the basis of the theory of transient phenomena as well as the nonlinear least-squares numerical method provided a unique time constant for the radical evolution in wheat flour during thermal treatment.     

Experiments on the gravity effect on the109Ag gamma resonance

The temperature dependence of the ¹⁰⁹Ag γ-ray self-absorption was investigated for the horizontal and vertical directions of emission. The source was a single-crystal silver plate containing atoms of parent radionuclide ¹⁰⁹Cd. Gamma-radiation of this γ-source and that of the monitoring γ-source, ⁵⁷Co, were registered by a pair of Ge(Li)-detectors. As a result of cooling the source from 77 K to ~12 K a relative decrease was observed of the intensity of the horizontally emitted γ-rays equal to 0.00064±0.00044. For the vertical direction the corresponding intensity change turned out to be -0.00047±0.00051. Although these data, as one would see, give some evidence for the possible effect of the gravitation on the resonant γ-ray absorption, future measurements must show if these results aren’t a consequence of any apparatus effect. The ways for developments in this study are discussed and some hindrances are considered. This revised version was published online in August 2006 with corrections to the Cover Date.