Effect of Ammonium Salts on the Solvent Extraction of Some Transition Metals with Liquid Cation Exchangers

The extractions of some transition metal ions from an ammoniacal solution with di-(2-ethyl hexyl) phosphoric acid and Versatic Acid 911 diluted in benzene were investigated in order to clarify the effect of ammonia on the solvent extraction. As regards the result, the extraction of these metals with D2EHPA was not affected by ammonia, while the extraction with Versatic Acid 911 was considerably affected. These results were discussed by the average ligand number of metal ammine complexes. Theoretical consideration on the solvent extraction in the presence of ammonia was performed to predict the extent of interference on the solvent extraction by the formation of metal ammine complexes in the aqueous phase. The results of this consideration were in good accordance with the experimental results of copper and zinc extraction, and were in near coincidence with the experimental results of nickel and cobalt extraction. However, there was no coincidence between the results of the theoretical consideration and the experimental results of cadmium extraction

Mechanism of strong quenching of photosystem II chlorophyll fluorescence under drought stress in a lichen, Physciella melanchla, studied by subpicosecond fluorescence spectroscopy

AbstractThe mechanism of the severe quenching of chlorophyll (Chl) fluorescence under drought stress was studied in a lichen Physciella melanchla, which contains a photobiont green alga, Trebouxia sp., using a streak camera and a reflection-mode fluorescence up-conversion system. We detected a large 0.31 ps rise of fluorescence at 715 and 740 nm in the dry lichen suggesting the rapid energy influx to the 715–740 nm bands from the shorter-wavelength Chls with a small contribution from the internal conversion from Soret bands. The fluorescence, then, decayed with time constants of 23 and 112 ps, suggesting the rapid dissipation into heat through the quencher. The result confirms the accelerated 40 ps decay of fluorescence reported in another lichen (Veerman et al., 2007 [36]) and gives a direct evidence for the rapid energy transfer from bulk Chls to the longer-wavelength quencher. We simulated the entire PS II fluorescence kinetics by a global analysis and estimated the 20.2 ns−1 or 55.0 ns−1 energy transfer rate to the quencher that is connected either to the LHC II or to the PS II core antenna. The strong quenching with the 3–12 times higher rate compared to the reported NPQ rate, suggests the operation of a new type of quenching, such as the extreme case of Chl-aggregation in LHCII or a new type of quenching in PS II core antenna in dry lichens

The Results of a New Distal Protection Method in Intervention for Chronic Total Occlusion of the Superficial Femoral Artery

Aims. To determine the efficacy of a new distal protection method in SFA CTO interventions. Methods and Results. From June 2003 to February 2009, ninety-two consecutive, chronic total occlusions of superficial femoral arteries were treated with catheter-based intervention using a bidirectional approach. Nine of these cases were managed with our original, distal protection method, based on symptoms, angiographic images, wire resistance, and intravascular ultrasound images. The average age was 73 years; eight patients were male. The mean occlusion length was 17.1 cm. A distal protection balloon was inserted from the retrograde sheath in the popliteal artery and placed distal to the occluded lesion after successful wire crossing. Lesion dilatation with a balloon was performed antegradely and debris was removed by 6Fr. guiding catheter. Debris was retrieved from all lesions, consisting mainly of thrombus. Where we decided not to use the distal protection method, there was no distal thromboembolism. Conclusion. In SFA-CTO intervention, the risk of distal embolization is 10%, which can be anticipated and eliminated by the distal protection method

Joint associations of physical activity and screen time with overweight among japanese adults

Background: although both insufficient physical activity (PA) and high screen time (ST) are independent risk factors for obesity, how the combination of sufficient/insufficient PA and high/low ST could increase obesity risk among the adult population of Japan is not known. This study examined joint associations of PA and ST with overweight among Japanese adults. Methods: an Internet-based survey collected data on height, weight, self-reported time spent in PA and ST, and sociodemographic variables from 2832 adults. Respondents were categorized into sufficient PA/low ST, sufficient PA/high ST, insufficient PA/low ST, or insufficient PA/high ST categories as per public PA guidelines and the median of ST. Logistic regression analysis examined the odds ratios (OR) of being overweight (body mass index, ≥ 25 kg/m2) according to the categories of PA and ST. Results: in comparison with the sufficient PA/low ST category, participants in the insufficient PA/high ST category were significantly more likely overweight (OR, 1.48; 95% confidence interval [95%CI), 1.14, 1.93) after adjusting for sociodemographic variables. A significantly higher OR for overweight (including obesity) among insufficient PA/high ST category was also observed in men, but no significant association was found in women. Conclusions: both insufficient PA and prolonged ST contribute to overweight and obesity among Japanese adults. Public health initiatives addressing obesity in Japan need to consider both promoting PA and reducing ST, especially in me