Effect of pulse-current-based protocols on the lithium dendrite formation and evolution in all-solid-state batteries.

Understanding the cause of lithium dendrites formation and propagation is essential for developing practical all-solid-state batteries. Li dendrites are associated with mechanical stress accumulation and can cause cell failure at current densities below the threshold suggested by industry research (i.e., >5 mA/cm2). Here, we apply a MHz-pulse-current protocol to circumvent low-current cell failure for developing all-solid-state Li metal cells operating up to a current density of 6.5 mA/cm2. Additionally, we propose a mechanistic analysis of the experimental results to prove that lithium activity near solid-state electrolyte defect tips is critical for reliable cell cycling. It is demonstrated that when lithium is geometrically constrained and local current plating rates exceed the exchange current density, the electrolyte region close to the defect releases the accumulated elastic energy favouring fracturing. As the build-up of this critical activity requires a certain period, applying current pulses of shorter duration can thus improve the cycling performance of all-solid-solid-state lithium batteries.

Why men have shorter lives than women: effects of resource availability, infectious disease, and senescence.

Senescence arises from age-specific deterioration of the soma as a consequence of optimization of life history, and such effects of senescence should appear when comparing species that differ in intensity of sexual selection, as well as when comparing, within a species, the two sexes that often differ in intensity of sexual selection. However, any extrinsic cause of mortality that reduces life expectancy will reduce the possibility of detecting sex-specific differences in senescence. We investigated geographical variation in human sex differences in longevity across 121 countries to test whether differences in sexual competition for limiting resources, reflecting intensity of sexual selection, affected sex differences in longevity. Men on average lived 5 years shorter than women. High rates of childhood morbidity and mortality reduced the sex difference in longevity, while increased overall longevity increased the sex difference in longevity. Increased resource availability estimated from gross domestic product per capita reduced the sex difference in longevity, accounting for 10% of the variance, while there was no additional effect of income inequality as reflected by the Gini coefficient. In a separate analysis of sex differences in longevity among the states of the US, there was a strong effect of the Gini coefficient on sex difference in longevity, with the negative effect on male longevity being stronger than that on female longevity. In contrast, there was only a marginal effect of average household income. Thus, there was evidence of increased competition for resources contributing to increased sex differences in longevity within a single nation.

Relation of race and sex to the use of reperfusion therapy in Medicare beneficiaries with acute myocardial infarction.

BACKGROUND: There are few reports describing the combined influence of the race and sex of a patient on the use of reperfusion therapy for acute myocardial infarction. METHODS: To determine the relation of race and sex to the receipt of reperfusion therapy for myocardial infarction in the United States, we reviewed the medical records of 234,769 Medicare patients with myocardial infarction. From these records we identified 26,575 white or black patients who met strict eligibility criteria for reperfusion therapy. We then performed bivariate and multivariate analyses of prevalence ratios to determine predictors of the use of reperfusion therapy in four subgroups of patients categorized according to race and sex: white men, white women, black men, and black women. RESULTS: Among eligible patients, white men received reperfusion therapy with the highest frequency (59 percent), followed by white women (56 percent), black men (50 percent), and black women (44 percent). After adjustment for differences in demographic and clinical characteristics, white women were as likely as white men to receive reperfusion therapy (prevalence ratio, 1.00; 95 percent confidence interval, 0.98 to 1.03). Likewise, black women were as likely as black men to receive reperfusion therapy (prevalence ratio, 1.00; 95 percent confidence interval, 0.89 to 1.13). However, black women were significantly less likely to receive reperfusion therapy than white men (prevalence ratio, 0.90; 95 percent confidence interval, 0.82 to 0.98), as were black men (prevalence ratio, 0.85; 95 percent confidence interval, 0.78 to 0.93). CONCLUSIONS: After adjustment for differences in clinical and demographic characteristics and clinical presentation, differences according to sex in the use of reperfusion therapy are minimal. However, blacks, regardless of sex, are significantly less likely than whites to receive this potentially lifesaving therapy.

Diode-pumped 1-W continuous-wave Er:YAG 3-mum laser.

We have demonstrated 1.15 W of Gaussianlike (M(2) = 2) cw output at 2.94 mum from a diode laser end-pumped monolithic laser crystal composed of Er-doped yttrium aluminum garnet (YAG) bonded to undoped YAG. The laser was pumped with two polarization-coupled 2.5-W flared laser diodes that provided a 45-mum pump waist with a low N.A. (<0.04) . Output at 2.94 mum was generated with a 34% slope efficiency and a greater-than-unity quantum efficiency.

Comparison of single photon emission computed tomography findings in cases of healthy adults and solvent-exposed adults.

Single photon emission computed tomography (SPECT) is a useful tool in measuring dynamic brain functioning. Its potential to reveal the physiological mechanisms of neurotoxicity has not been fully explored. In the present study, the SPECT findings for 25 healthy control subjects were compared to the findings for 25 mixed organic solvent exposure subjects. Specific physiological abnormalities related to regional cerebral blood flow activity (rCBF) were revealed. In the early phase of uptake, significantly decreased uptake was found in the mixed organic solvent group; in the late phase of uptake, a significant increase in uptake was found in specific regions of interest. The discovery of this abnormality in brain functioning may be a significant step toward the creation of a biological marker of neurotoxicity. Early detection of neurotoxicity is important in occupational medicine to prevent neurotoxic illnesses in working populations.

Semimonolithic Nd:YAG ring resonator for generating cw single-frequency output at 1.06 microm.

We report 2.1 W of unidirectional single-frequency laser output from a novel Nd:YAG ring laser longitudinally pumped by a laser diode bar. The resonator requires only a single discrete optic and magnet, in addition to the laser medium, for stable multiwatt single-frequency operation. Undoped YAG is diffusion bonded to the Nd:YAG laser crystal at the pump face to eliminate residual spatial hole burning and improve thermal conductivity. This new laser design can be scaled to higher powers through more facile diode access and is useful for cw intracavity doubling.

The anesthetic management of a patient with chromosome 10qter deletion syndrome.

Terminal deletions of chromosome 10q are uncommon. The resulting syndrome includes cardiac and facial anomalies, urogenital abnormalities, limb defects, and mental retardation. Most affected infants require surgical correction of these anomalies. Presented are features inherent in the syndrome that will aid the anesthesiologist in the perioperative management of such patients.

Single photon emission computed tomography of the brain in patients with chemical sensitivities.

Chemical sensitivities display a recurrent pattern on scintigraphic examinations of the brain. The pattern can include mismatching between early and late imaging, multiple hot and cold foci distributed throughout the cortex without regard to lobar distribution (salt and pepper pattern), temporal asymmetries, and sometimes increased activity in the basal ganglia. This study used Desert Shield/Desert Storm veterans who present with abnormal neurological and psychological symptoms as a model to exhibit abnormalities by brain scintigraphy. These are typical of those seen in patients with documented exposure to neurotoxic compounds who develop a clinical syndrome that has been termed "chemical sensitivity." Exposure to cocaine, alcohol, and other substances of abuse can result in abnormal scintigrams of the brain using tracers such as [technetium-99m]hexamethylpropyleneoxime. This study used techniques combining regional cerebral blood flow data with delayed distributional data after the intracellular conversion of the tracer into a hydrophilic molecule. In addition to delayed image abnormalities, a mismatch occurs in the regional activity between the two image sets of the veterans. This degree of mismatch was not seen in control subjects who were screened for avoidance of neurotoxic agents. Patterns identified from examinations performed on patients with known exposure to petroleum distillates, pesticides and other materials linked with neurotoxicity were identified in some veterans of the Desert Shield/Desert Storm operation. A single case of repeated examinations on a veteran showed a reversion of these patterns toward normal after therapy. This reversion followed independent assessments of clinical improvement.

Laser ablation and the production of polymer films.

The formation of high-quality thin films of polytetrafluoroethylene (PTFE) is important in many applications ranging from material reinforcement to molecular electronics. Laser ablation, a technique widely used to deposit a variety of inorganic materials, can also be used as a simple and highly versatile method for forming thin polymer films. The data presented show that PTFE films can be produced on various supports by the evaporation of a solid PTFE target with a pulsed ultraviolet laser. The composition of the ablation plume suggests that PTFE ablation and subsequent film formation occur by way of a laser-induced pyrolitic decomposition with subsequent repolymerization. The polymer films produced by this method are composed of amorphous and highly crystalline regions, the latter being predominantly in a chain-folded configuration with the molecular axis aligned parallel to the substrate surface.

Laser micromanipulation in the mouse embryo: a novel approach to zona drilling.

OBJECTIVE: To introduce the use of excimer lasers for penetration of the zona pellucida for micromanipulation purposes. DESIGN: Cryopreserved two-cell mouse embryos were thawed and exposed to the 248-nm line of a krypton fluoride excimer laser (Lambda Physik EMG 202, Goettingen, Germany) creating a 2 to 4-micron opening in the zona pellucida. SETTING: The Laser Ablation Laboratory at DuPont and the in Vitro Fertilization Laboratory at The Medical Center. INTERVENTIONS: The embryos were exposed in either phosphate-buffered solution (PBS) or modified human tubal fluid (HTF) with the laser power varying from 1 to 2 J/cm2 and cultured in Ham's F-10 medium (GIBCO, Grand Island, NY) with 0.4% bovine serum albumin. MAIN OUTCOME MEASURES: The outcome of each experiment was measured by blastocyst formation of laser-exposed embryos as compared with a set of unexposed control embryos handled in a similar fashion. RESULTS: Successful laser penetration of the zona pellucida was achieved using the 248-nm line of a krypton fluoride excimer laser. A higher blastocyst formation was found for embryos exposed in PBS. The higher optical absorption of the modified HTF partially inhibited embryo development. The blastocyst statistics increased 2.5-fold times by reducing the exposure of the embryos to ablation by-products. CONCLUSIONS: The use of a krypton fluoride excimer laser was introduced as a new method to open the zona pellucida of two-cell mouse embryos without interrupting blastocyst formation.

Absorption coefficient at 10.6 microm in CdTe modulator crystals.

The bulk and surface absorption coefficients of CdTe modulator crystals at 10.6 microm were compared with those of single-crystal KC1 and NaCl which served to calibrate the laser calorimeter. High-resistivity (>10(7) ohm/cm) CdTe crystals exhibited a bulk absorption coefficient of 0.0014 cm(-1).

Fluorescence ambient NO(2) monitor with flashlamp pumping.

A pulsed xenon flashlamp unit was developed to provide a sensitive, economical, and compact device for determination of ambient NO(2) concentrations. The basic principles of operation are similar to a laser fluorescence monitor previously developed at the Aerospace Corporation that detects the atmospheric NO(2) by the fluorescence resulting from absorption of laser radiation. The prototype flashlamp unit has a sensitivity of 5 ppb for a 1.3-min integration time, a linear response, and provides a direct digital readout in real time. Results obtained in monitoring ambient NO(2) levels in the vicinity of the Aerospace Corporation are presented.

Atmospheric NO(2) determination by 442-nm laser induced fluorescence.

An atmospheric monitor with a detectability of 0.6 ppbv, utilizing a compact He-Cd laser at 442 nm for excitation of the NO(2) molecules is described. Photon-counting techniques were employed to detect the NO(2) fluorescence transmitted through a bandpass liquid solution filter that did not fluoresce upon absorption of scattered laser light. Operational characteristics of the instrument are described. Results obtained in ambient air monitoring are presented.