Development of DRAGON electron cyclotron resonance ion source at Institute of Modern Physics

A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.

Status of the laser ion source at IMP

A laser (Nd:YAG laser, 3 J, 1064 nm, 8-10 ns) ion source has been built and under development at IMP to provide pulsed high-charge-state heavy ion beams to a radio frequency quadrupole (RFQ) for upgrading the IMP accelerators with a new low-energy beam injector. The laser ion source currently operates in a direct plasma injection scheme to inject the high charge state ions produced from a solid target into the RFQ. The maximum power density on the target was about 8.4 × 10(12) W∕cm(2). The preliminary experimental results will be presented and discussed in this paper.

[The clinical significance of evolution of paroxysmal nocturnal haemoglobinuria clones in aplastic anemia patients]

OBJECTIVE

To explore the clinical significance of evolution of paroxysmal nocturnal hemoglobinuria (PNH) clones in aplastic anemia (AA) patients.

METHODS

The positive rate of PNH clones in 678 AA cases at first diagnosis from January 2002 to December 2009 were analyzed, and to compare the response rate and overall survival (OS) between AA patients with or without PNH clones. All patients were sequentially followed-up to assess the incidence rate and risk factors for AA evolving to overt PNH.

RESULTS

(1) Of 119/678 (17.6%) AA patients at initial diagnosis presented with PNH clones,the positive rates of PNH clones among non-severe AA (NSAA), severe AA (SAA) and very severe AA (VSAA) were 16.7% (37/ 222), 17.3% (45/260) and 18.9% (37/196), respectively. There was no statistical difference among the three groups. (Chi2 = 0.369; P = 0.832); (2) 678 newly diagnosed AA cases were divided into 5 subgroups according to PNH clones, severity of disease and treatment regimens. There was no statistical difference among the five subgroups regarding 6m-response rate (RR) and OS. (3) Serial follow-up revealed that persistent PNH negative clones were found in 516 (76.1%) cases, and evolved to PNH positive clones after therapy in 43 (6.3%) cases. Persistent PNH positive clones were found in 72 (10.6%) cases, and disappeared the clones after treatment in 47 (6.9%) cases. There was no statistical difference among the four subgroups in terms of the 6m RR (Chi2 = 2.489,P = 0.426) and OS (P = 0.477); (4) 17 out of 678 AA cases (2.5%) evolved to overt PNH and the estimated incidence of evolution to overt PNH was (3.7 +/- 0.9)% at 10 years. The incidences of AA patients with or without PNH clones at initial diagnosis evolved to overt PNH were 3.4% and 2.3%, respectively. There was no statistical difference between the two groups, (Chi2 = 0.111; P = 0.739); and so was found in OS by Kaplan-Meier analysis (P = 0.868). Cox regression model analysis showed that none of the severity of AA, with or without PNH clone at initial diagnosis, treatment regimen and 6m RR was the risk factor for evolution to overt PNH.

CONCLUSION

There is no difference between AA patients presented with or without PNH clones at initial diagnosis regarding the RR and prognosis. The appearance of PNH clones in AA is not identified as a risk factor for developing into overt PNH.

A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transport

The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

Study of ion beam transport from the SECRAL electron cyclotron resonance ion source at the Institute of Modern Physics

Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper.

Oxygen vacancy density-dependent transformation from infrared to Raman active vibration mode in SnO2 nanostructures

Raman spectra acquired from spherical, cubic, and cuboid SnO2 nanocrystals (NCs) reveal a morphologically independent Raman mode at ∼302 cm(-1). The frequency of this mode is slightly affected by the NC size, but the intensity increases obviously with decreasing NC size. By considering the dipole changes induced by oxygen vacancies and derivation based on the density functional theory and phonon confinement model, an oxygen vacancy density larger than 6% is shown to be responsible for the transformation of the IR to Raman active vibration mode, and the intensity enhancement is due to strong phonon confinement.

Protective effects of melatonin against oxidative stress in flow cytometry-sorted buffalo sperm

Previous reports of the ability of melatonin to scavenge a variety of toxic oxygen and nitrogen-based reactants suggest that melatonin could be an effective antioxidant for protecting sperm. In this study, flow cytometry and laser tweezers Raman spectroscopy were used to evaluate the effect of melatonin on buffalo sperm quality to optimize sperm sex-sorting procedures. In fresh sperm incubated in the presence or absence of melatonin (10(-4)  m) for 1, 24, 48 h or 72 h at 27°C, the mitochondrial activity was significantly higher than in a non-melatonin control (p < 0.05). Also, during the flow-sorting process, sperm in melatonin-supplemented groups had higher (p < 0.05) mitochondrial activity than the control. The intensity of Raman spectra from sperm frozen in media supplemented with melatonin was significantly weaker than that for non-melatonin-treated groups, except for a band at 1302 per cm. Thus, melatonin helps to protect buffalo sperm from reactive oxygen species induced by staining, sorting and freezing and increases semen quality after the freezing-thawing processes. Furthermore, the results indicate the high potential of the laser tweezers Raman spectroscopy technique for rapid, effective and non-invasive assessment of the quality of sperm cells.

[Long-term follow-up of malignant clonal evolution in patients with acquired aplastic anemia]

OBJECTIVE

To assess the incidence and risk factors for evolution of acquired aplastic anemia (AA) into myelodysplastic syndrome/acute myeloid leukemia (MDS/AML).

METHOD

A total of 1003 AA patients hospitalized in our institute hospital between January 1991 and December 2009 enrolled into this study. The incidence and risk factors for AA developing MDS/AML by the Kaplan-Meier method and Cox proportional hazards models, respectively.

RESULTS

The median follow-up was 62 (2 - 423) months and the projected 5-year survival rate was (78.0 +/- 1.0)%. Twenty-seven patients evolved to MDS/AML, of whom 11, 6 and 10 were from NSAA, SAA and VSAA subgroups, respectively. The estimated cumulative incidence of MDS/AML transformation for these 1003 patients after diagnosis was (4.5 +/- 1.0)% at 10 year. The incidence of MDS/AML transformation in VSAA subgroup [(12.8 +/- 3.5)%] was significantly higher than in NSAA subgroup [(4.1 +/- 1.9)%] (P < 0.001) and SAA subgroup [(3.5 +/- 1.4)% ] (P = 0.008), but no difference between the latter two subgroups (P = 0.616). Age [RR = 3.527 (95% CI: 1.598 - 7.784), P = 0.002], severity of disease [RR = 5.122 (95% CI: 2.214 - 11.853), P < 0.001], the duration (days) of rhuG-CSF therapy [RR = 10.782 (95% CI: 4.600 - 25.269), P < 0.001] and exposure to ray, chemicals or drugs [RR = 3.401 (95% CI: 1.535 - 7.534), P = 0.003] were risk factors for the transformation in both univariate and multivariate analyses.

CONCLUSION

Long-term follow-up is essential to assess the incidence and risk factors for evolutions of acquired AA into MDS/AML, and to administer salvage therapy for transformation in time during follow-up.

Transfection of hairpin small interfering RNA expression vector targeting rat nuclear factor (NF) (κB) inhibits rat cell proliferation induced by NF-κB signal pathway activation

OBJECTIVE

The aim of this work was to construct one small interfering RNA (siRNA) eukaryotic expression vector targeting rat nuclear factor (NF)κB p65 and identify its inhibition effect on cell proliferation according to its down-regulation of NF-κB pathway.

METHODS

The p65siRNA expression vector "pGenesil-1.2-p65siRNA" and negative control plasmid "HK" were transfected into the cultured rat cells. After transfection, cells were divided into 4 treatment groups: 1) control cells cultured in complete. Dulbecco modified Eagle medium; 2) lipopolysaccharide (LPS) (1 μg/mL); (3) LPS (1 μg/mL) + HK-transfected; 4) LPS (1 μg/mL) + p65siRNA (pGenesil-1.2-p65siRNA). Thereafter, the protein levels of NF-κB p65 in the cells were detected by Western blotting at 72 hours after LPS stimulation. Furthermore, to observe cell proliferation, the proliferative rate of the cell growth was evaluated by the methylthiazolyl tetrazolium assay (at 24, 48, and 72 hours). The cell cycle distribution at 72 hours was detected by flow cytometry.

RESULTS

p65siRNA effectively down-regulated the protein level of p65 (P < .05). Meanwhile, the proliferation of cells transfected with p65siRNA expression vector was significantly inhibited (P < .05), the ratio of cells at G(0)/G(1) stage markedly increased, and the proportion of cells at S stage was significantly decreased among transfected compared with control cells (P < .05).

CONCLUSIONS

p65siRNA effectively suppressed NF-κB, expression, inhibiting rat cell proliferation induced by NF-κB signal pathway activation.

Annexin A1 expression and its prognostic significance in human breast cancer

Annexin A1 (ANXA1) is a calcium- and phospholipid-binding protein and is considered to play an important role in tumorigenesis. However, the correlation between ANXA1 expression and tumor clinicopathological features in patients with breast cancer remains unclear. This study investigated the prognostic value of ANXA1 protein as breast cancer marker. Tissue microarray blocks, containing 20 cases of non-tumor breast tissue, 20 cases of benign breast lesion and 135 cases of breast cancer (107 with lymph node metastasis), were constructed. Expression of ANXA1 in these specimens was analyzed using immunohistochemistry. In non-tumor tissue and benign breast lesions, myoepithelial cells showed strong expression of ANXA1. Negative ANXA1 expression was significantly associated with advanced disease stage (P<0.05), especially pathological-N stage (P<0.01). The patients with loss of ANXA1 expression in tumor tissues showed a significantly worse overall survival compared with positive ones (P<0.05). ANXA1 did not correlate well with estrogen receptor (ER), progesterone receptor (PR) and HER2/neu status. Moreover, the level of ANXA1 expression in lymph node metastases was higher than corresponding primary breast cancer. These results suggest that ANXA1 may play a multifaceted role in breast cancer development, progression, and metastases.

[Treatment of severe aplastic anemia with intensified immunosuppressive therapy and two different regimens with recombinant human granulocyte colony-stimulating factor: a retrospective study based on long-term follow-up]

OBJECTIVE

To compare the efficacy and safety of two different regimens with recombinant human granulocyte colony-stimulating factor (rhG-CSF) combined with intensified immunosuppressive therapy (IIST) in severe aplastic anemia (SAA).

METHODS

Retrospectively analyzed 176 SAA treated with IIST and rhG-CSF in our hospital from March 1994 to December 2007. Regimen A (Group A, n = 96), rhG-CSF 300 µg/d was initiated on day 31 after IIST and subcutaneously administered 1-3 days a week for 3 months. Regimen B (Group B, n = 80), rhG-CSF was initiated at 5 µg·kg(-1)·d(-1) before IIST until hematologic recovery.

RESULTS

(1) The early response rate of Group B (67.5%) was significantly higher than that of Group A (37.5%) (P < 0.01), the interval from IIST to response in Group B was shorter than that in Group A. Moreover, infection-related deaths during first 4 months after IIST were significantly reduced in Group B (6.3%) when compared with Group A (16.7%) (P = 0.034). The cumulative incidence of survival at 4 years in Groups B [(77.7 ± 4.9)%] was also significantly higher than that in Group A [(57.2 ± 5.1)%] (P = 0.006). (2) With regard to 93 refractory patients with no response 4 months after IIST, rhG-CSF therapy was continued in Group B meanwhile stopped in Group A. There were no differences between two groups in terms of survival and the response rates (P = 0.288, 0.066), but there was an increasing risk of evolving into MDS/AML in Group B (22.3%) when compared with Group A (3.71%) (P = 0.023). (3) By multivariate analysis, the severity of disease (P = 0.010, RR = 1.922) and the early response (P < 0.01, RR = 5.749) were associated with the overall survival. Moreover, the number of days of rhG-CSF therapy was the only significant risk factor for SAA evolving into MDS/AML (P = 0.017, RR = 1.004).

CONCLUSIONS

The early initiation of rhG-CSF therapy with proper dose might contribute to a desirable early response and reduced infection-related death rate, but extended administration of rhG-CSF did not improve the long-term outcome of refractory SAA and may further facilitate the progression of SAA into MDS/AML.

New development of advanced superconducting electron cyclotron resonance ion source SECRAL (invited)

Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e microA of (129)Xe(43+), 22 e microA of (209)Bi(41+), and 1.5 e microA of (209)Bi(50+). To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e microA of (129)Xe(27+) and 152 e microA of (129)Xe(30+), although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and (129)Xe(27+), (78)Kr(19+), (209)Bi(31+), and (58)Ni(19+) beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented.

Production of highly charged ion beams with SECRAL

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e microA of Xe(37+), 1 e microA of Xe(43+), and 0.16 e microA of Ne-like Xe(44+). To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi(31+) beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e microA of Bi(31+), 22 e microA of Bi(41+), and 1.5 e microA of Bi(50+) have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

Performance of PAC/PDM composite coagulants for removal of algae from Lake Taihu waters in summer

The enhanced coagulation of algae-rich raw water from Lake Taihu in summer was studied by use of composite coagulants. The composite coagulants were composed of polyaluminum chloride (PAC) and polydimethyldiallylammonium chloride (PDM) with various intrinsic viscosity values (0.55-3.99 dL/g) and different mass percentages (5-20%) in the formulation. For raw water with temperature of 28-29 degrees C and algae content of 3.60x10(4)-3.70x10(4) cells/ml, the algae-removal rates of 89.0% and 89.3-93.1% could be realized by using PAC and PAC/PDM (0.55/5%-3.99/20%) with dosages of 8.37 mg/L and 5.93-3.58 mg/L, respectively, when 2 NTU residual turbidity of treated water after sedimentation was required. Compared with using PAC only, the removal rate of CODMn using PAC/PDM increased at least 4.4% when the dosage was 8 mg/L, and increased at least 5.0% when the dosage was 10 mg/L. The composite coagulants could still function well when raw water quality deteriorated and algae content reached 8.00x10(4) cells/ml. The enhanced coagulation efficiency of PAC/PDM (0.55/5%) could be better than that of PAC combined with prechlorination process when the same dosages are used.

The proteasome inhibitor bortezomib inhibits intimal hyperplasia of autologous vein grafting in rat model

OBJECTIVE

Increasing evidence indicates that inflammation plays an important role in intimal hyperplasia (IH) induced by autologous vein grafts. The proteasome inhibitor bortezomib shows anti-inflammatory effects, so we used an autologous vein transplantation model to test whether bortezomib inhibits neointimal formation in transplant-induced vasculopathy.

MATERIALS AND METHODS

We subjected 88 rats to autologous external jugular vein grafting surgery randomly assigned to be treated with bortezomib or vehicle. After 24 or 72 hours, rats were humanely killed and vein grafts processed for real-time RT-PCR (24 and 72 hours), ELISA (24 hours), or neutrophil chemotaxis assay (24 hours). Subsequently, rats were humanely killed at 1 and 2 weeks after grafting with samples processed for morphometric analysis.

RESULTS

Bortezomib significantly inhibited IH at 2 weeks compared with untreated controls (P < .05). Expression of mRNA for vascular cell adhesion molecule-1, intercellular adhesion molecule-1, cytokine-induced neutrophil chemoattractant 2beta, monocyte chemoattractant-1, interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha markedly increased in injured vessels during the first day after surgery declining over the following 3 days. Bortezomib significantly attenuated gene expression and protein levels of most inflammatory mediators (P < .05), simultaneously inhibiting neutrophil chemotactic activity of vessel homogenates.

CONCLUSIONS

Bortezomib inhibited neointimal formation at least partially by attenuating the inflammatory response in transplant-induced vasculopathy. It may become a novel vasoprotective agent in the clinical field.

p11 is up-regulated in the forebrain of stressed rats by glucocorticoid acting via two specific glucocorticoid response elements in the p11 promoter

Posttraumatic stress disorder (PTSD) is one of the most common psychiatric disorders. Despite the extensive study of the neurobiological correlates of this disorder, the underlying mechanisms of PTSD are still poorly understood. Recently, a study demonstrated that dexamethasone (Dex), a synthetic glucocorticoid, can up-regulate p11, known as S100A10-protein which is down-regulated in patients with depression, (Yao et al., 1999; Huang et al., 2003) a common comorbid disorder in PTSD. These observations led to our hypothesis that traumatic stress may alter expression of p11 mediated through a glucocorticoid receptor. Here, we demonstrate that inescapable tail shock increased both prefrontal cortical p11 mRNA levels and plasma corticosterone levels in rats. We also found that Dex up-regulated p11 expression in SH-SY5Y cells through glucocorticoid response elements (GREs) within the p11 promoter. This response was attenuated by either RU486, a glucocorticoid receptor (GR) antagonist or mutating two of three glucocorticoid response elements (GRE2 and GRE3) in the p11 promoter. Finally, we showed that p11 mRNA levels were increased in postmortem prefrontal cortical tissue (area 46) of patients with PTSD. The data obtained from our work in a rat model of inescapable tail shock, a p11-transfected cell line and postmortem brain tissue from PTSD patients outline a possible mechanism by which p11 is regulated by glucocorticoids elevated by traumatic stress.

Extreme ultraviolet narrow band emission from electron cyclotron resonance plasmas

Extreme ultraviolet lithography (EUVL) is considered as the most promising solution at and below dynamic random access memory 32 nm half pitch among the next generation lithography, and EUV light sources with high output power and sufficient lifetime are crucial for the realization of EUVL. However, there is no EUV light source completely meeting the requirements for the commercial application in lithography yet. Therefore, ECR plasma is proposed as a novel concept EUV light source. In order to investigate the feasibility of ECR plasma as a EUV light source, the narrow band EUV power around 13.5 nm emitted by two highly charged ECR ion sources -- LECR2M and SECRAL -- was measured with a calibrated EUV power measurement tool. Since the emission lines around 13.5 nm can be attributed to the 4d-5p transitions of Xe XI or the 4d-4f unresolved transition array of Sn VIII-XIII, xenon plasma was investigated. The dependence of the EUV throughput and the corresponding conversion efficiency on the parameters of the ion source, such as the rf power and the magnetic confinement configurations, were preliminarily studied.

Experimental study of hot electrons in LECR2M plasma

In order to investigate the hot electron component in electron cyclotron resonance (ECR) plasmas, the volume bremsstrahlung spectra in the x-ray photon energy range were measured with a high-purity germanium detector on Lanzhou ECR Ion Source No. 2 Modified (LECR2M). A collimation system similar to Bernhardi's was used to focus at the central part of the plasma. The ion source was operated under various source conditions with argon; sometimes oxygen was added to enhance high charge state ion beam intensities. The spectral temperature of hot electrons T(spe) was derived from the measured bremsstrahlung spectra. The evolution of the deduced temperature of hot electrons T(spe) with the ion source parameters, such as the rf frequency, power, and the magnetic confinement configuration, was investigated.

An electron cyclotron resonance ion source based low energy ion beam platform

To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.

[Construction of T-vectors for the direct, unidirectional cloning and analysis of PCR-amplified promoters]

The amplification and cloning of promoters are regularly employed procedures to study the mechanism of gene regulation. In the present study we developed a method to construct T-vectors used for the direct and unidirectional cloning and analysis of promoters. These so-called T-vectors pEGFP-T and pGL3-T were derived from their parent promoterless vectors pEGFP-1 and pGL3-basic, respectively. To construct the T-vectors, an AhdI recognition site within the Ampr gene in pGL3-basic was silent mutated using overlap extension PCR. Then, a specially designed AhdI cassette was cloned into the respective parent vectors. The procedures of the T-vector construction involved a strategy to minimize the background of nonrecombinant transformants and to eliminate reverse orientation of the PCR products into the T-vectors. The cloning efficiencies of the two T-vectors were both above 85% when tested with a PCR product amplified from a sequence that was pre-confirmed to be able to initiate transcription, and moreover, the constructs harbored the inserts in a desired orientation at a >90% rate. In transient transfection assays, we demonstrated these T-vectors are functional. Thus, the present study provides an easy method to construct a series of T-vectors used for promoter characterization.

36-segmented high magnetic field hexapole magnets for electron cyclotron resonance ion source

Two high magnetic field hexapoles for electron cyclotron resonance ion source (ECRIS) have successfully fabricated to provide sufficient radial magnetic confinement to the ECR plasma. The highest magnetic field at the inner pole tip of one of the magnets exceeds 1.5 T, with the inner diameter (i.d.)=74 mm. The other hexapole magnet provides more than 1.35 T magnetic field at the inner pole tip, and the i.d. is 84 mm. In this article, we discuss the necessity to have a good radial magnetic field confinement and the importance of a Halbach hexapole to a high performance ECRIS. The way to design a high magnetic field Halbach structure hexapole and one possible solution to the self-demagnetization problem are both discussed. Based on the above discussions, two high magnetic field hexapoles have been fabricated to be utilized on two high performance ECRISs in Lanzhou. The preliminary results obtained from the two ECR ion sources are given.

Study on the error in the dynamic spectrum method relative with the pathlength factor as a function of wavelength

Utilizing near-infrared spectroscopy for non-invasive blood component concentration sensing has been a focusing topic in biomedical optics applications. The ease of use, low cost and portability of these methods is a clear advantage over the invasive blood component concentration sensing which is the main sensing method in the clinic application. However, there is no report about any successful non-invasive blood components (except the artery blood oxygen saturation) concentration detection techniques that can meet the requirements of clinic application. One of the most key difficulties is the influence of the individual discrepancy. Dynamic spectrum (DS) is a new measure method of non-invasive blood components concentration sensing presented recently. It can eliminate the individual discrepancy of the tissues except the pulsatile component of the artery blood (PCAB) theoretically. This indicates a brand new way to measure the blood components concentration and a potential to provide absolute quantitation of hemodynamic variables. One of the systematic errors in the calculation of the component changes from NIRS data of the dynamic spectrum is the absolute magnitudes and relative differences in pathlength factors as a function of wavelength. Monte Carlo simulations are used in this paper to examine the importance and mitigation methods of this error while the photoelectric pulse wave is detected on the finger tip. We found wavelength selection to be important variables in minimizing such errors, and replacing the average pathlength factor with the subsection pathlength factor appropriately could reduce the error to a small fraction (10%).

Spectroscopic analysis of iron-oxide minerals in aerosol particles from northern China

Diffuse reflectance spectrometry was used to study iron-oxide minerals and to investigate the reflectance characteristics of eolian dust collected during the spring of 2001 and 2002 on bulk filters from three sites in northern China. The first derivatives of the reflectance spectra were consistent with signals from two iron-oxide minerals, hematite and goethite, at wavelengths of 565 and 435 nm, respectively, and these values varied with the iron concentrations in the samples. The percent reflectances for the yellow, orange and red bands increased with the iron concentrations and with the first derivative values representing hematite and goethite while those for violet, blue and green bands decreased correspondingly. The results show that iron-oxide minerals play an important role in determining the aerosol particles' color and reflectance properties. Moreover, the relative amounts of the two iron-oxides in Asian dust apparently differ from those in African dust, suggesting that the iron-oxides may provide another tool for tracing the origins of eolian dust on a global scale.

Incoherent subharmonic light scattering in isotropic media

Incoherent subharmonic light scattering in isotropic media is a new kind of nonlinear light scattering, which involves single input photon and multiple output photons of equal frequency. We investigate theoretically the dependence of the subharmonic scattering intensity on the hyperpolarizability of molecules and the incident intensity using nonlinear optics theory similar to that used for Hyper-Rayleigh scattering and degenerate optical parametric oscillators. It is derived that the subharmonic scattering intensities grow exponentially or superexponentially with the hyperpolarizability of molecules and the incident intensity.