Effects of simulated microgravity and hypergravity on the senescence of oat leaf segments excised from the primary leaves of 8-d-old green seedlings were studied using a 3-dimensional (D) clinostat ...as a simulator of weightlessness and a centrifuge, respectively. During the incubation with water under 1-g conditions at 25 °C in the dark, the loss of chlorophyll of the segments was found dramatically immediately after leaf excision, and leaf color completely turned to yellow after 3-d to 4-d incubation. In this case kinetin (10 μM) was effective in retarding senescence. The application of simulated microgravity conditions on a 3-D clinostat enhanced chlorophyll loss in the presence or absence of kinetin. The loss of chlorophyll was also enhanced by hypergravity conditions (ca. 8 to 16 g), but the effect was smaller than that of simulated microgravity conditions on the clinostat. Jasmonates (JAs) and abscisic acid (ABA) promoted senescence under simulated microgravity conditions on the clinostat as well as under 1-g conditions. After 2-d incubation with water or 5-d incubation with kinetin, the endogenous levels of JAs and ABA of the segments kept under simulated microgravity conditions on the clinostat remained higher than those kept under 1-g conditions. These findings suggest that physiological processes of leaf senescence and the dynamics of endogenous plant hormone levels are substantially affected by gravity.
Recent research aims at developing a biomarker to predict antidepressant treatment outcomes in major depressive disorder. The Antidepressant Treatment Response (ATR) index has been correlated with ...response to antidepressant medication (, ) but has not been assessed in a placebo-controlled trial. EEGs recorded at pretreatment baseline and after 1 week of randomized treatment were used to calculate ATR index for 23 subjects with major depressive disorder who were treated for 8 weeks with fluoxetine (FLX) 20 mg (n = 12) or placebo (n = 11). The 17-item Hamilton Depression Rating Scale (HamD17) assessed symptom severity; ATR index was assessed as a predictor of percent change in HamD17 score, endpoint response (≥ 50% improvement) and remission (HamD17 score ≤ 7). The ATR index was significantly associated with improvement on FLX (r = 0.64, P = 0.01), with a higher mean ATR index for FLX responders than for nonresponders (t(10) = -2.07, P = 0.03). Receiver operating characteristic analysis found a 0.83 area under the curve (P = 0.03), for ATR index as a predictor for FLX, while an optimized ATR index cutoff of 47.3 yielded 100% sensitivity, 66.7% specificity, 75% positive predictive value, and 100% negative predictive value. Importantly, ATR index did not correlate significantly with placebo outcomes. Results extend ATR index findings to include predictive validity with fluoxetine, suggesting that this biomarker has specificity for drug effects.
2,4-Dinitrophenol (2,4-DNP) is frequently used as a starting material in the production of pesticides, herbicides, and dyes. This compound is toxic to animals, plants, and microorganisms because it ...inhibits respiration in mitochondria and photophosphorylation in chloroplasts.
Anabaena variabilis showed a high ability to remove 2,4-DNP in the concentration range of 5–150
μM under continuous light. However, 2-amino-4-nitrophenol (2-ANP), which is a degradation product of the 2,4-DNP removal by
A. variabilis, accumulated in the culture. Although 2,4-DNP was completely removed when incubation was with a light and dark cycle, accumulation of 2-ANP was observed. By screening various microalgae and cyanobacteria for their ability to remove 2-ANP, we found that
Chlamydomonas reinhardtii and
Anabaena cylindrica showed the highest ability. However, a high concentration of 2-ANP remained when
C. reinhardtii was cultivated with
A. variabilis. On the other hand, a mixed culture of
A. variabilis and
A. cylindrica could remove 2,4-DNP completely, and only a low concentration of 2-ANP was detected compared to a culture of
A. variabilis. Therefore, a cyanobacterial mixed culture of
A. variabilis and
A. cylindrica is expected to be useful for the removal of 2,4-DNP from industrial wastewater.
The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm ...mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga
Euglena gracilis as a producer, the ciliate protozoan
Tetrahymena thermophila as a consumer and the bacterium
Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of γ-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation.
The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. ...The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide-MoS sub(2)-using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.
Effects of long‐term suppression of bone remodeling by bisphosphonate were investigated in cortical bone of dog rib. Although microdamage was accumulated, BMD was increased without increasing ...cortical bone area. Consequently, the intrinsic material properties were not reduced.
Introduction: Recently, we have reported that long‐term suppression of bone remodeling increases microdamage accumulation but is not necessarily associated with vertebral fragility because of compensated increase of bone mass and improved microarchitecture. This study aimed to investigate the effect of long‐term suppression of bone remodeling by bisphosphonate on the degree of mineralization, accumulation of microdamage, and mechanical properties of cortical bone in the same dogs.
Materials and Methods: Twenty‐nine 1‐year‐old beagles (15 males, 14 females) were divided into three groups and treated daily with vehicle (CNT) or with incadronate at a dose of 0.3 (LOW) or 0.6 mg/kg/day (HIGH) orally for 3 years. After death, pQCT, histomorphometry, microdamage measurements, and three‐point bending mechanical test were performed using the ninth rib.
Results: Cortical BMD was increased in the incadronate‐treated groups. Cortical activation frequency was suppressed by 82% and 70% in HIGH and LOW, respectively, compared with CNT, without impairment of mineralization. Microdamage accumulation was increased in both incadronate‐treated groups. Although there were no significant differences in total and cortical area among the three groups, structural mechanical properties were significantly increased after incadronate treatment while intrinsic material properties were not changed in the incadronate‐treated groups.
Conclusion: This study suggests that long‐term suppression of bone remodeling by bisphosphonate increases microdamage accumulation. However, this was not necessarily associated with a reduction of intrinsic material properties probably because of an increased degree of mineralization.
High-electron-mobility ZnO epilayers are grown on
c-plane sapphire with ZnO/MgO double-buffer layers by plasma-assisted molecular beam epitaxy. Reflection high-energy electron diffraction and ...transmission electron microscopy analysis showed the growth mode of ZnO buffer layers (LT-ZnO) grown at low temperature significantly affected the structural properties of the ZnO epilayers grown at high temperature, thereby affecting the electrical properties of the epilayers. When LT-ZnO was grown at a high-growth-rate, three-dimensional growth dominated and threading dislocation (TD) density was as high as ca. 1×10
10
cm
−2. By using the low growth rate of LT-ZnO, two-dimensional growth dominated and TD density was reduced by one order of magnitude, down to ca. 2×10
9
cm
−2, yielding significantly improved electrical properties of the ZnO epilayers. The highest electron mobility in as-grown undoped ZnO film, 145
cm
2
V
−1
s
−1, was achieved at room temperature, comparable to the mobility previously reported for high-quality bulk ZnO.
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