Encoding Information on the Excited State of a Molecular Spin Chain

The quantum states of nano-objects can drive electrical transport properties across lateral and local-probe junctions. This raises the prospect, in a solid-state device, of electrically encoding information at the quantum level using spin-flip excitations between electron spins. However, this electronic state has no defined magnetic orientation and is short-lived. Using a novel vertical nanojunction process, these limitations are overcome and this steady-state capability is experimentally demonstrated in solid-state spintronic devices. The excited quantum state of a spin chain formed by Co phthalocyanine molecules coupled to a ferromagnetic electrode constitutes a distinct magnetic unit endowed with a coercive field. This generates a specific steady-state magnetoresistance trace that is tied to the spin-flip conductance channel, and is opposite in sign to the ground state magnetoresistance term, as expected from spin excitation transition rules. The experimental 5.9 meV thermal energy barrier between the ground and excited spin states is confirmed by density functional theory, in line with macrospin phenomenological modeling of magnetotransport results. This low-voltage control over a spin chain's quantum state and spintronic contribution lay a path for transmitting spin wave-encoded information across molecular layers in devices. It should also stimulate quantum prospects for the antiferromagnetic spintronics and oxides electronics communities.     

Erratum to “Experimental study on the air/water counter-current flow limitation in a model of the hot leg of a pressurized water reactor”

This paper replaces the paper published in the journal by Deendarlianto et al. (2008). Because of an error in the implementation of the air flow meter some of the data given by Deendarlianto et al. (2008) are wrong. They are corrected within the present paper. The general results and conclusions remain unchanged.An experimental investigation on the air/water counter-current two-phase flow in a horizontal rectangular channel connected to an inclined riser has been conducted. This test-section representing a model of the hot leg of a pressurized water reactor is mounted between two separators in a pressurized experimental vessel. The cross-section and length of the horizontal part of the test-section are (0.25 m × 0.05 m) and 2.59 m, respectively, whereas the inclination angle of the riser is 50°. The flow was captured by a high speed camera in the bended region of the hot leg, delivering a detailed view of the stratified interface as well as of dispersed structures like bubbles and droplets. Counter-current flow limitation (CCFL), or the onset of flooding, was found by analyzing the water levels measured in the separators. The counter-current flow limitation is defined as the maximum air mass flow rate at which the discharged water mass flow rate is equal to the inlet water mass flow rate.From the high-speed observations it was found that the initiation of flooding coincides with the formation of slug flow. Furthermore, a slight hysteresis was noticed between flooding and deflooding. The CCFL data was compared with similar experiments and empirical correlations available in the literature. Therefore, the Wallis-parameter was calculated for the rectangular cross-sections by using the channel height as length, instead of the diameter. The agreement of the CCFL curve is good, but the zero liquid penetration was found at lower values of the Wallis parameter than in most of the previous work. This deviation can be attributed to the special rectangular geometry of the hot leg model of HZDR, since the other investigations were done for pipes.     

A broad-band microwave superconducting thin-film transformer

The design, construction, and testing of a broadband superconducting transformer based on a Dolph-Chebyshev distribution are described. The transformer is completely compatible with thin-film circuit topologies and allows access to 50-Ω coaxial launchers. The transformer is a taper that utilizes only one side of the substrate and features a coplanar waveguide to microstrip transition without the use of via holes. The taper provides a characteristic impedance transformation from 50 Ω to 2 Ω over a frequency range from 5 to 15 GHz. The taper provides a much larger bandwidth than a linear taper with the same length and impedance transformation     

On self-adaptive features in real-parameter evolutionary algorithms

Due to the flexibility in adapting to different fitness landscapes, self-adaptive evolutionary algorithms (SA-EAs) have been gaining popularity in the recent past. In this paper, we postulate the properties that SA-EA operators should have for successful applications in real-valued search spaces. Specifically, population mean and variance of a number of SA-EA operators such as various real-parameter crossover operators and self-adaptive evolution strategies are calculated for this purpose. Simulation results are shown to verify the theoretical calculations. The postulations and population variance calculations explain why self-adaptive genetic algorithms and evolution strategies have shown similar performance in the past and also suggest appropriate strategy parameter values, which must be chosen while applying and comparing different SA-EAs     

Clinical relevance of thiamine status amongst hospitalized elderly patients

BACKGROUND: The prevalence and the consequences of thiamine deficiency among elderly patients admitted to acute geriatric wards are not known. OBJECTIVES: (1) To assess the prevalence of thiamine deficiency in patients admitted to a geriatric ward compared to age-matched ambulatory outpatients; (2) to identify their diseases and problems associated with thiamine deficiency, and (3) to determine the relationship between the thiamine status and the cognitive and functional status of these patients. MATERIALS AND METHODS: 118 aged hospitalized patients (83 +/- 7 years; mean age +/- SD) were prospectively enrolled on admission to the geriatric ward. Their cognitive status was assessed using the Mini-Mental State Examination (MMSE) and their ability to perform their activities of daily living (ADL) using ADL scales. The effect of exogenous thiamine pyrophosphate (TPP) addition on the blood transketolase (TK) activity (TPP TK effect) served to estimate thiamine deficiency. Socioeconomic data, diseases and treatment were identified as potential associated risk factors. This group of hospitalized patients was divided according to their thiamine status to characterize the conditions associated with thiamine deficiency. Thirty-five outpatients without any functional or cognitive impairment served as a control group. RESULTS: Of 118 inpatients, 46 (39%) presented with a TPP TK effect of >15%, and 6 with values of >22%, indicating moderate and severe thiamine deficiency, respectively. Only 6 of 30 outpatients (20%) exhibited a TPP TK effect of >15% and none of them reached values of >18%. Although it tended to be lower in outpatients, the mean TPP TK effect did not statistically differ from the mean of inpatients. Thiamine-deficient inpatients comprised a larger proportion of institutionalized subjects than nondeficient inpatients (87 versus 47%, p < 0.001). Functional status, cognitive functions and the occurrence of delirium did not differ according to their thiamine status. By contrast, thiamine-deficient inpatients exhibited a higher proportion of Alzheimer's disease, depression, cardiac failure and falls. Furosemide was more frequently taken by thiamine-deficient patients. CONCLUSIONS: Severe thiamine deficiency remained quite low among the hospitalized elderly. The prevalence of moderate thiamine deficiency approached 40%. Institutionalized subjects were at particular risk of developing thiamine deficiency. Its clinical relevance on functional status and on cognitive function remained not significant. By contrast, a high proportion of falls, Alzheimer's disease, depression, cardiac failure and furosemide use could have been related to thiamine deficiency.