Assessment of the mechanical suppression of nonuniform electrodeposition in lithium metal batteries.

Dendrite formation is a long-standing issue in lithium metal batteries. Replacing the conventional liquid electrolytes with semi-solid ones, the non-uniform lithium growth can be potentially mitigated by the mechanical deformation in the solid matrix. The underlying dendrite suppression mechanism is investigated in this study using a mechano-electrochemical phase-field method. Two indicators, namely the arithmetic average height and the elongation rate, are proposed to characterize the surface roughness of lithium dendrites. Our simulation results are summarized in two-dimensional design maps as a function of the porosity and the elastic modulus of the semi-solid electrolytes, which could provide us the guidance for the development of dendrite-free lithium metal batteries.

An Analytical Energy Harvester Model for Interdigitated Ring Electrode on Circular Elastic Membrane.

Energy harvesters are devices that accumulate ambient vibrational energy from the environment, and for the time being, variable capacitance is the most widely used mechanism. Various designs were proposed to increase the power of such devices, and in particular, the interdigitated electrode (IDE) pattern is the mainstream. Nevertheless, most IDE designs focus merely on the parallel-type vibrations of electrodes. In this study, the performance of a novel harvester, which combined circular membrane and interdigitated ring electrodes (IRE), was investigated. This design allows the device to collect energy from the rotational structure motions of electrodes through the vibrating membrane. Besides, the circular structure provides a dense capacitive arrangement that is higher than that of the arrangement obtained using regular rectangular chips. The IRE diagram is composed of many capacitive rings, each of which harvests vibrated energy simultaneously. Three gaps (1, 10, and 100 µm) of the ring are investigated for the first four vibrational modes of the membrane to understand the effect of energy output. It is found that the energy outputs are approximately the same for the three gaps; however, rings with a wider gap are easier to manufacture in MEMS.

Sophisticated oil film geometries through incomplete electrical dewetting by feedback control and Fourier construction.

Existing techniques for electronic control of the interface between two immiscible fluids are typically limited to simple periodic geometries (symmetric waves) or spherical geometries (only two principle radii of curvature). Presented here, is a new technique with much more sophisticated electronic control of fluid meniscus geometry. Previously undemonstrated two-fluid interfaces, such as asymmetric saw-tooth profiles, are created by dynamic modulation of an incomplete dewetting state for an oil film covering an array of control electrodes, with the oil film itself covered by an electrically conductive fluid acting as the ground electrode. Two distinct approaches are demonstrated: (1) application of voltages, electrical capacitance sensing of meniscus geometry, followed by further feedback control of the applied voltages based on the sensed electrical capacitance; (2) use of multiple periodic voltage waveforms and wave propagation across the meniscus to build up complex meniscus geometries by Fourier construction. These approaches are demonstrated in this work by a proven electro-hydrodynamic modeling method, which couples the Maxwell stress tensor with the laminar phase field of the oil-water dual phase. This work could serve numerous applications including particle or fluid transport (e.g. lab-on-chip), or adaptive optical surfaces (e.g. liquid prism arrays). Importantly, the results can be achieved using conventional materials, and the fluids respond with speeds that are adequately slow (ms-µs) such that even conventional control electronics (µs-ns) are more than adequate. Furthermore, because the conducting fluid never dewets the oil film from the solid surface, dielectric degradation issues are likely eliminated.

Acquired coagulant factor VIII deficiency induced by Bacillus anthracis lethal toxin in mice.

Mice treated with anthrax lethal toxin (LT) exhibit hemorrhage caused by unknown mechanisms. Moreover, LT treatment in mice induced liver damage. In this study, we hypothesized that a suppressed coagulation function may be associated with liver damage, because the liver is the major producing source of coagulation factors. The hepatic expression of coagulant factors and the survival rates were analyzed after cultured cells or mice were exposed to LT. In agreement with our hypothesis, LT induces cytotoxicity against hepatic cells in vitro. In addition, suppressed expression of coagulation factor VIII (FVIII) in the liver is associated with a prolonged plasma clotting time in LT-treated mice, suggesting a suppressive role of LT in coagulation. Accordingly, we further hypothesized that a loss-of-function approach involving treatments of an anticoagulant should exacerbate LT-induced abnormalities, whereas a gain-of-function approach involving injections of recombinant FVIII to complement the coagulation deficiency should ameliorate the pathogenesis. As expected, a sublethal dose of LT caused mortality in the mice that were non-lethally pretreated with an anticoagulant (warfarin). By contrast, treatments of recombinant FVIII reduced the mortality from a lethal dose of LT in mice. Our results indicated that LT-induced deficiency of FVIII is involved in LT-mediated pathogenesis. Using recombinant FVIII to correct the coagulant defect may enable developing a new strategy to treat anthrax.

Field assessment of Orientia tsutsugamushi infection in small mammals and its association with the occurrence of human scrub typhus in Taiwan.

We conducted an extensive study in Taiwan of Orientia tsutsugamushi (OT) infection in small wild mammals. Field trapping was carried out at six districts in eastern and western Taiwan as well as various offshore islands during the period 2006-2010. A total of 1061 specimens representing 11 rodent species were captured. The presence of OT infection was assessed by indirect immunofluorescence assay and polymerase chain reaction assays of 56-kDa type-specific antigen gene. The chigger infestation rate among the animals was 35% (371/1061). Among these, OT was detected in 64% (238/371) of the chiggers from the infested animals and in the spleens from 273 (34.3%) of 797 animals. Excluding animals in the Suncus murinus group, the antibody positive rate of scrub typhus was 69.1% (477 of 690 of serum samples). The prevalence of OT infection in animals from areas with a low incidence of human cases of scrub typhus was significantly lower than that in rodents obtained from regions with a high incidence of human cases of the disease (44.4%±4.0% vs. 71.2%±9.7%, p<0.001). In Taiwan, the prevalence of OT infection in wild rodents is considerably high and appears to correlate positively with the occurrence of scrub typhus in humans.

Intruder-induced asymmetry in compartmentalized granular gases.

The clustering behavior of a compartmentalized monodisperse granular gas with the addition of one heavy intruding particle is investigated experimentally. Depending on the number of particles, the presence of a heavy intruder leads to three population states: a homogeneous state, an expelled clustering state, and a fully clustering state. These states are found to be consistent with the clustering of a purely monodisperse granular gas in an asymmetric compartmentalized structure. We obtain an exact relation between the size of an intruder and the elevation of the compartment bottom. This relation quantifies the particle-expelling ability of a heavy intruder, and suggests that the one-intruder system is a type of asymmetric system with an intruder-size-related asymmetrical index ξ. Under the framework of the flux model, a ξ-associated Ξ function is proposed to quantitatively reproduce the experimental results.

Two types of oscillation in unequally compartmentalized granular gases.

Granular oscillation in an unequally two-compartmentalized system is investigated experimentally, yielding two time periods: τ(LS) represents the time period for particles moving from the large to the small compartment, and τ(SL) is the time needed for movement in a reverse direction. We construct the phase diagram for the unequal system, discovering that there exist two different granular oscillation states. In the GOI state, τ(LS)>τ(SL) is observed, and (τ(LS)-τ(SL)) increases as the difference between the two compartment widths is enlarged. In contrast, τ(LS)<τ(SL) is found in the GOII state, where the total number of particles is considerably lower than that in the GOI state. A flux model, accompanied by a proposed generalized granular temperature, is adopted to quantitatively calculate the observed time periods for both granular oscillation states. We find that the proposed temperature in each compartment is crucial in discriminating τ(LS) from τ(SL), and this is supported by the molecular dynamics analysis of mean kinetic energy of particles in a single compartment.

Detection of asymptomatic paroxysmal atrial fibrillation with the trans-telephonic electrocardiograph system.

Paroxysmal atrial fibrillation (PAF) carries an equally high annual stroke rate as chronic atrial fibrillation (AF). Furthermore, the frequency and duration of PAF are thought to be associated with stroke risk. In this pilot study, a trans-telephonic electrocardiograph (TTE) monitoring system was used to detect asymptomatic PAF and to study the relationship between ischemic stroke and the frequency of PAF. Between December 2004 and April 2006, 70 patients enrolled in the TTE monitoring program. Patients either transmitted electrocardiograms (ECGs) daily or upon experiencing cardiac symptoms. Of the 70 patients included, 25 were diagnosed with PAF. In total, 11% (855/7,768) of the recordings were diagnosed as PAF, yet less than 2% of total calls collected and less than 17% of all the calls with PAF were associated with obvious symptoms. Four patients developed five ischemic strokes resulting in a calculated annual stroke rate of 0.56%. Patients with stroke had more episodes of AF (56.5±106.3 versus 6.7±85.9, p=0.685) and symptomatic AF episodes (9.8±17.5 versus 4.9±8.1, p=0.381) than the patients who did not have a stroke, but the differences were not statistically significant because of the low numbers of patients and episodes. Most PAF episodes were asymptomatic, and the TTE system could easily detect these episodes. Furthermore, these four patients tended to have more episodes of PAF and more symptomatic attacks of PAF than patients who did not have a stroke.

Intruder-induced change in condensation temperature of granular gases.

The process from a gaseous state to a clustering state for a compartmentalized monodisperse granular gas is accompanied by a drop in the granular temperature to a condensation point. We show experimentally that adding an intruder generally results in a decrease in the condensation point, and a heavier intruder makes this decrease more pronounced. However, once the Brazil nut effect (the intruder on the top of clustering grains) occurs, the condensation point will rise. Through the balance of particle fluxes and the hydrodynamic balance of driving forces, we analytically calculated the condensation point for the monodisperse gases and the intruder-fluid mixtures. The analytical results match the experimental data.

Genetic typing, based on the 56-kilodalton type-specific antigen gene, of Orientia tsutsugamushi strains isolated from chiggers collected from wild-caught rodents in Taiwan.

Orientia tsutsugamushi is the etiological agent of scrub typhus, a mite-borne, febrile illness that occurs in the Asia-Pacific region. We conducted strain characterization of O. tsutsugamushi isolates from chiggers obtained from rodents based the nucleotide sequence of the 56-kDa outer membrane protein gene. With the use of PCR, a total of 68 DNA sequences of 56-kDa antigen genes were amplified. Phylogenetic analysis revealed that there were at least six definable clusters among the 68 isolates: 37% Karp-related strains (25/68), 27% TA763 strains (18/68), 12% JG-related strains (8/68), 19% Kato-related strains (13/68), 4% divergent strains (3/68), and 1% representing a Gilliam prototype strain (1/68). Overall, the O. tsutsugamushi genotypes exhibited a high degree of diversity, similar to that seen in strains from the rest of the areas where scrub typhus is endemic. Moreover, the 56-kDa protein sequence similarity between O. tsutsugamushi isolates from mites and those from human patients (H. Y. Lu et al., Am. J. Trop. Med. Hyg. 83:658-663, 2010) were striking, thus highlighting potential risk factors for this emerging zoonotic disease.

The thicker the skin fold, the less hematoma development: a novel parameter other than body mass index associated with transradial vascular complication.

It was reported recently that body mass index (BMI) is a prognostic factor of vascular complications after radial puncture, and that extremely thin patients are at higher risk than obese subjects. However, the underlining mechanism of this phenomenon has rarely been studied. Therefore, we conducted a survey measuring a novel parameter, the skin fold thickness, and other potential risk factors in our patients developing postprocedure hematoma. In 1176 consecutive patients undergoing percutaneous radial catheterization, 18 (1.53%) developed hematoma afterward. When a patient with hematoma had been identified, the next patient having no hematoma after radial puncture was enrolled into the control group, which thus turned out to have 18 patients. In addition, we also compared the BMI, skin fold thickness, and other potential risk factors, including heparin dosage and antiplatelet medication, between these 2 groups. We found hematoma patients to be older (69.5 +/- 10.3 years vs 61.50 +/- 11.7 years, P = .037), to have more cases of coronary intervention (10/18 vs 4/18, P = .04), to have lower BMI (23.63 +/- 4.03 vs 27.25 +/- 4.38, P = .014), and to have thinner skin folds of forearm (5.94 +/- 4.56 vs 9.27 +/- 3.06 mm, P = .015), deltoid area (14.61 +/- 9.00 vs 19.73 +/- 7.15 mm, P = .042), and waist (21.94 +/- 9.90 vs 29.00 +/- 8.46 mm, P = .028) than the nonhematoma group. On the contrary, no statistical difference in heparin dosage or other factors was noted between the 2 groups. We conclude that the vascular complication rate after radial catheterization is higher in elderly patients with lower BMI, body weight, or thinner skin folds.

More coronary artery stenosis, more cerebral artery stenosis? A simultaneous angiographic study discloses their strong correlation.

Cerebral artery stenosis (CAS) has the same pathogenesis as coronary artery disease (CAD), but the coexistence of these two diseases has been rarely reported. To detect coexistent CAS in CAD patients, we conducted a study of simultaneous coronary and cerebral angiography. Of the 663 consecutive newly diagnosed CAD patients who had not yet been explored to have CAS, 80 were admitted to undergo angiography of bilateral carotid and vertebral system during the same procedure. We defined significant vascular stenosis, either located intracranially or extracranially, as the lesions of diameter stenosis more than 50%. Association between carotid or vertebral stenosis and their potential risk factors were also analyzed. Of our patients, 18 (22.5%) had significant extracranial vascular stenosis, 14 (17.5%) suffered from intracranial stenosis, and 20 (25%) had both. Only 28 patients (35%) had no significant intracranial or extracranial stenosis. None of the demographic parameters as hypertension or diabetes showed significant differences between the cerebral patent group and the CAS group, except for the number of coronary stenotic vessels (1.71 +/- 0.81 versus 2.69 +/- 0.64, P < 0.001). The number of coronary stenotic vessels is correlated well to the number of cerebral stenotic lesions (r = 0.562, P < 0.001). Besides, 8 of the cerebral stenotic patients and 2 of the cerebral patent patients had ischemic stroke previously. We conclude the CAS is coexistent in more than half of the CAD patients in this study. Our study also implies a proportional increase in the severity of CAS to CAD severity.

Calyculin A sensitive protein phosphatase is required for Bacillus anthracis lethal toxin induced cytotoxicity.

Previous studies have shown that the Bacillus anthracis lethal toxin can induce both necrosis and apoptosis in mouse macrophage-like J774A.1 cells depending on both the toxin concentration and the phosphatase activity. In this study several protein kinase or phosphatase inhibitors were employed to evaluate the hypothesis that the lethal toxin induces cell death via protein phosphorylation processes. Pretreatment with a serine/threonine phosphatase inhibitor Calyculin A (300 nM) could inhibit about 78% of cell death induced by the lethal toxin, whereas inhibitors of kinases, such as H7, HA, Sphingosine, and Genestein, but other inhibitors of phosphatases, such as Okadaic acid, Tautomycin, and Cyclosporin A, did not. In addition, recent reports have demonstrated that the MEK1 protein may serve as a proteolytic target within its N-terminus for lethal factor cleavage. In this study, Calyculin A is shown to enhance the phosphorylation of the MEK1 protein. This prevents the cleavage of the MEK1 by lethal factor. These results suggest that a putative Calyculin A-sensitive protein phosphatase is involved in anthrax toxin induced cytotoxicity and that the blocking effect of Calyculin A on lethal factor cytotoxicity may be mediated through the MEK signaling pathway.