[en] Soils contain large quantities of Fe, however, the Fe-solubility is very low. Plants have developed two efficient strategies to secure Fe uptake from soil under Fe-deficient conditions: (i) the sequential acidification-reduction-transport strategy (strategy I) and (ii) the chelation-based strategy (strategy II). All processes involved in the Fe cycle in soil-plant systems can fractionate stable Fe isotopes. Hence, I (i) conducted a systematic review about the state of Fe isotope researchin plant studies and highlighted the research gaps. Then I supplemented this theoretical study by two experiments: I (ii) examined the effect of different Fe availabilities on Fe isotope fractionation in wheat plants under controlled conditions and I (ii) investigated the effect of 50 years of irrigation on Fe isotope fractionation in soils and cereals in a long-term field experiment. My review suggested that strategy I plants especially take up light Fe isotopes, while strategy II plants fractionate less towards light isotopes. Above ground tissues usually show even lighter Fe isotope signatures than the roots, with flowers (δ${}^{56}$Fe: -2.15 to -0.23‰) being isotopically the lightest. I found that all reported strategy I plants consistently enriched light Fe isotopes under all growth conditions. Strategy II plants, however, could be enriched with either light or heavy Fe isotopes, depending on the growth conditions. Depending on the Fe speciation and concentration present in the growth medium, some strategy II plants like rice are able to adapt their uptake strategy as they also possess ferrous transporters and are hence also able to take up Fe(II) ions. In a greenhouse study, I cultivated summer wheat (Triticum aestivum L.) under Fe-sufficient (control, 0.0896 mM Fe-EDTA) and deficient (Fe-deficient, 0.0022 mM Fe-EDTA) conditions. Plants were sampled at different growth stages (vegetative and reproductive growth stages) and separated into different plant organs (root, stem, leaf, spike/grain). All samples were analyzed for their Fe concentrations and δ${}^{56}$Fe isotope compositions. The results showed that Fe-deficiency reduced the whole plant Fe mass by 59% at vegetative growth. During reproductive growth, Fe mass fluxes indicated different preferential Fe translocation pathways under different Fe supply. Under Fe-deficient conditions, Fe uptake from growth substrate increased whereas under Fe sufficient conditions Fe was preferentially redistributed within the plant. Under Fe-sufficient conditions increasingly lighter δ${}^{56}$Fe values from older to younger plant parts were found, but no indications that the chelation-based uptake strategy was activated. However, with serious shortage of Fe, the shift towards lighter δ${}^{56}$Fe values was reduced. This suggested that Fe isotope ratios can reflect both wheat growth conditions and ages. In a field study, I sampled wheat plants and Retisol soil cores down to a depth of 100 cm from along-term irrigation treatment at Berlin-Thyrow. The irrigated plots had higher Fe${}_{avail}$ concentrations than the non-irrigated plots in the top 40 cm of soil, but there were no changes in δ${}^{56}$Fe values. Due to the research site being one of the driest areas in Germany with hardly a meaningful water percolation, the maximum difference of δ${}^{56}$Fe${}_{avail}$ values between 40 to 50 cm and 70 to 100 cm was explained soil pedogenesis rather than irrigation treatment. The wheat plants grown in both irrigated and non-irrigated plots were slightly enriched in light Fe isotopes, exhibiting similar δ${}^{56}$Fe values to those of the respective topsoil. I concluded that the overall δ${}^{56}$Fe signature of wheat was regulated by plant-homeostasis and specific on-site soil characteristics, whereas irrigation had little if any significant effect on the Fe isotopes in the crops. Overall, my study showed that the Fe isotope compositions of wheat plants were not affected by Fe availabilities in substrate until the anthesis stage. However, during the reproductive growth phase with sufficient Fe supply, δ${}^{56}$Fe values of different plant organs showed significant Fe fractionation. The former processes were hardly affected by irrigation.

[en] Zero resistance and Meissner effect are two crucial experimental evidences of superconductivity in determining a new kind of superconductor, which can be detected by transport and diamagnetic measurements. In this paper, we briefly review the main transport and magnetization results on the one unit cell (1-UC) FeSe films grown on SrTiO_3 (STO) substrates from our team in recent years, which identify the high temperature superconductivity in 1-UC FeSe films. (topical review)

[en] An increase of work function (0.3 eV) is achieved by irradiating poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film in vacuum with 254-nm ultraviolet (UV) light. The mechanism for such an improvement is investigated by photoelectron yield spectroscopy, X-ray photo electron energy spectrum, and field emission technique. Surface oxidation and composition change are found as the reasons for work function increase. The UV-treated PEDOT:PSS film is used as the hole injection layer in a hole-only device. Hole injection is improved by UV-treated PEDOT:PSS film without baring the enlargement of film resistance. Our result demonstrates that UV treatment is more suitable for modifying the injection barrier than UV ozone exposure

[en] We fabricate the Tm-doped double cladding silica fiber by using the vapor-solution hybrid-doping method, then build up an all-fiber Tm-doped fiber laser which can provide the output power of up to 121 W, corresponding to a slope efficiency of 51% and an optical-optical efficiency of 48%. By using the domestic Tm-doped fiber, it is the first time a hundred-watt level output at 1915nm has been achieved, to the best of our knowledge. The thermal effect of Tm-doped fiber laser is also analyzed. (paper)

[en] Our previous studies have shown that atRA treatment resulted in cell-cycle block and growth inhibition in mouse embryonic palatal mesenchymal (MEPM). In the current study, gestation day (GD) 13 MEPM cells were used to test the hypothesis that the growth inhibition by atRA is due to apoptosis. The effects of atRA on apoptosis were assessed by performing MTT assay, Cell Death Detection ELISA and flow cytometry, respectively. Data analysis confirmed that atRA treatment induced apoptosis-like cell death, as shown by decreased cell viability and increased fragmented DNA and sub-G1 fraction. atRA-induced apoptosis was associated with upregulation of bcl-2, translocation of bax protein to the mitochondria from the cytosol, activation of caspase-3 and cytochrome c release into cytosol. atRA-induced apoptosis was abrogated by z-DEVD-fmk, a caspase-3 specific inhibitor, and z-VAD-fmk, a general caspase inhibitor, suggesting that the atRA-induced cell death of MEPM cells occurs through the cytochrome c- and caspase-3-dependent pathways. In addition, atRA treatment caused a strong and sustained activation of c-Jun N-terminal kinase (JNK) and p38 kinase (p38), as well as an early but transient activation of extracellular signal-regulated kinase (ERK). Importantly, atRA-induced DNA fragmentation and capase-3 activation were prevented by pretreatment with the JNK inhibitor (SP600125) and the p38 MAPK inhibitor (SB202190), but not by pretreatment with MEK inhibitor (U0126). From these results, we suggest that mitogen-activated protein kinase-dependent pathways is involved in the atRA-induced apoptosis of MEPM cells

[en] Objective: To identify the key factors affecting the time of proton and carbon ion radiotherapy by analyzing the timing characteristics of the accelerator system and to find out potential solutions to enhance treatment efficiency. Methods: The log files for 47 patients with different types of tumors treated with proton beams and carbon ion beams were analyzed. Lung cancer patients were treated with the gating technology. The timing characteristics of beam delivery were analyzed and potential solutions to enhance treatment efficiency were explored. Results:The mean spill time and mean cycle time per iso-energy slice (IES) for proton radiotherapy with beam gating technology were (2.98 ± 1.98) s and (5.71 ± 4.51) s, which were longer than the radiotherapy without using gating technology. The mean total cycle time for treatment without using gating technology was approximately 7 min for both proton and carbon ion beams. The mean total cycle time for lung cancer treatment using gating technology was approximately 15 min. Conclusion: Application of mini-ridge filter or ripple filter to reduce per IES numbers and use of passive breath hold technology to eliminate interruptions during beam delivery in each IES for gating radiotherapy are two feasible approaches to improve treatment efficiency for this specific machine. (authors)

[en] We demonstrate a kW continuous-wave ytterbium-doped all-fiber laser oscillator with all domestic fiber components: a 7 × 1 fused fiber bundle combiner, a fiber Bragg grating and a double-clad gain fiber. The oscillator operates at 1079.48 nm with 80.94% slope efficiency and shows no limit of temperature and nonlinear effects. These indicate that the passive fiber components and the gain fiber are all qualified for the high power environment. No evidence of the signal power roll-over shows that this oscillator possesses the capacity to higher output with available pump power. (paper)

[en] Objective: To evaluate the dosimetric difference between carbon ion radiotherapy and photon radiotherapy for treating tumors at lacrimal system. Methods: Using the CT images of 10 patients with tumors at lacrimal system, the carbon ion plan, the photon volume intensity modulation plan (VMAT) and the fixed wild photon intensity modulation radiotherapy (IMRT) plan were generated. The prescription was 54 Gy (RBE) in 18 fractions for clinical target volume (CTV) and 63 Gy (RBE) in 18 fractions for CTV-boost. Dosimetric differences of organ at risks were compared based on the same planning target volumes (PTVs) with similar dose coverages. Results: There was no statistically significant difference in the PTV coverage among three plans (P > 0.05). Compared to VMAT and IMRT plans, carbon ion plans reduced the mean doses of eyeballs, mean doses and near-maximum doses of optical nerves of both ipsilateral (t = 7.35, 3.79, 4.66, 8.48, 2.52, 2.76, P < 0.05) and contralateral eyes (t = 3.87, 10.49, 9.16, 4.43, 6.53, 5.12, P < 0.05), while the mean dose of brain was decreased from (5.65 ± 3.58) and (5.76 ± 2.09) Gy (RBE) to (0.81 ± 0.90) Gy (RBE) (t = 6.76, 17.33, P < 0.05). Conclusions: Compared to photon VMAT or IMRT, carbon ion could reduce the doses to optical critical organs around tumors. Thus, carbon ion radiotherapy has potential to reduce patients' radiation related side-effects. (authors)

[en] Objective: To investigate the dosimetric difference between glioma patients treated by particle (proton + carbon ion) and photon radiotherapy. Methods: Twelve previously-treated glioma patients were selected, and given with the same total dose of 60.00 Gy [RBE]. Two types of planning target volumes (PTVs) including PTV-ion and PTV-photon were expended from clinical target volumes according to range uncertainty and patient setup errors. Based on PTV-ion, proton plans with sequential carbon ion boost (particle plan) were created. Following the same prescription, two types of photon intensity-modulated radiotherapy (IMRT) plans were established to achieve similar target coverage and compare the dose of organs at risk. Results: Target coverages of three types of plans had no statistical difference (all P > 0.05). The median integral dose of normal brain of all patients receiving particle plan was merely 44.90% of the minimum number from photon plans (P < 0.001). Compared with the minimum number from photon plans, particle radiotherapy decreased the mean dose of brain stem [(6.83 ± 6.22) Gy [RBE] vs. (15.10 ± 10.11) Gy [RBE], P = 0.001)], the maximum dose of chiasm [(47.76 ± 20.80) Gy [RBE] vs. (49.59 ± 20.52) Gy [RBE], P = 0.009)] and the mean dose of contralateral hippocampus (0.26 ± 9.08) Gy [RBE] vs. (16.28 ± 11.14) Gy [RBE], P = 0.002), respectively. Conclusions: Particle radiotherapy can achieve similar target coverage while maintaining lower normal tissue doses to the photon radiotherapy. Photon + carbon ion can increase the doses to adjuvant normal tissues. (authors)

[en] Recent experiments showed that thinning gallium, iron selenide and 2H tantalum disulfide to single/several monoatomic layer(s) enhances their superconducting critical temperatures. Here, we characterize these superconductors by extracting the absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the transition temperature from their self-field critical currents. Our central finding is that the enhancement in transition temperature for these materials arises from the opening of an additional superconducting gap, while retaining a largely unchanged ‘bulk’ superconducting gap. Literature data reveals that ultrathin niobium films similarly develop a second superconducting gap. Based on the available data, it seems that, for type-II superconductors, a new superconducting band appears when the film thickness becomes smaller than the out-of-plane coherence length. The same mechanism may also be the cause of enhanced interface superconductivity. (paper)