Large optical depth frequency modulation spectroscopy.

Band-resolved frequency modulation spectroscopy is a common method to measure weak signals of radiative ensembles. When the optical depth of the medium is large, the signal drops exponentially and the technique becomes ineffective. In this situation, we show that a signal can be recovered when a larger modulation index is applied. Noticeably, this signal can be dominated by the natural linewidth of the resonance, regardless of the presence of inhomogeneous line broadening. We implement this technique on a cesium vapor, and then explore its main spectroscopic features. This work opens the road towards measurement of cooperative emission effects in bulk atomic ensemble.

Cooperative Emission of a Pulse Train in an Optically Thick Scattering Medium.

An optically thick cold atomic cloud emits a coherent flash of light in the forward direction when the phase of an incident probe field is abruptly changed. Because of cooperativity, the duration of this phenomena can be much shorter than the excited lifetime of a single atom. Repeating periodically the abrupt phase jump, we generate a train of pulses with short repetition time, high intensity contrast, and high efficiency. In this regime, the emission is fully governed by cooperativity even if the cloud is dilute.

Cooperative Emission of a Coherent Superflash of Light.

We investigate the transient coherent transmission of light through an optically thick cold strontium gas. We observe a coherent superflash just after an abrupt probe extinction, with peak intensity more than three times the incident one. We show that this coherent superflash is a direct signature of the cooperative forward emission of the atoms. By engineering fast transient phenomena on the incident field, we give a clear and simple picture of the physical mechanisms at play.

Carotid endarterectomy improves peripheral but not central arterial stiffness.

OBJECTIVE: Carotid endarterectomy (CEA) reduces the risk of cerebrovascular events due to the presence of atherosclerotic plaque in the internal carotid artery. Arterial stiffness is an indicator of cardiovascular risk and strongly associates with the development of atherosclerosis. This study aims to assess the short-term effect of CEA on arterial stiffness and haemodynamics. DESIGN: Prospective observational study. METHODS: Measurements of arterial stiffness and haemodynamics, including carotid-femoral pulse wave velocity (cfPWV), carotid-radial PWV (crPWV), augmentation pressure, augmentation index, subendocardial viability ratio, central pressures and pulse pressure amplification, were performed pre- and 6 weeks post-CEA on both surgical and non-surgical sides. RESULTS: Fifty-nine patients completed the study (n = 46 men, age 68.9 ± 10.1 years). crPWV was decreased after CEA on the surgical (P = 0.01) and non-surgical side (P = 0.0008), AIx75 tended to decrease only on the surgical side (P = 0.06). cfPWV did not change significantly on either side. CONCLUSION: We assessed, for the first time, the short-term effect of CEA on arterial stiffness and haemodynamics. CEA improved peripheral but not central arterial stiffness. This study provides evidence for significant changes in certain arterial stiffness and haemodynamic parameters. Longer-term follow-up will assess whether these changes are sustained and whether CEA is associated with further haemodynamic benefits.

A modified dynamic evolving neural-fuzzy approach to modeling customer satisfaction for affective design.

Affective design is an important aspect of product development to achieve a competitive edge in the marketplace. A neural-fuzzy network approach has been attempted recently to model customer satisfaction for affective design and it has been proved to be an effective one to deal with the fuzziness and non-linearity of the modeling as well as generate explicit customer satisfaction models. However, such an approach to modeling customer satisfaction has two limitations. First, it is not suitable for the modeling problems which involve a large number of inputs. Second, it cannot adapt to new data sets, given that its structure is fixed once it has been developed. In this paper, a modified dynamic evolving neural-fuzzy approach is proposed to address the above mentioned limitations. A case study on the affective design of mobile phones was conducted to illustrate the effectiveness of the proposed methodology. Validation tests were conducted and the test results indicated that: (1) the conventional Adaptive Neuro-Fuzzy Inference System (ANFIS) failed to run due to a large number of inputs; (2) the proposed dynamic neural-fuzzy model outperforms the subtractive clustering-based ANFIS model and fuzzy c-means clustering-based ANFIS model in terms of their modeling accuracy and computational effort.

Synthesis of Co3O4 nanowire arrays supported on Ni foam for removal of volatile organic compounds.

Crystalline Co3O4 nanowire arrays freely supported on Ni foam are successfully synthesized using a template-free method. The effects of reaction time, concentration of reactants, and temperature on the morphology of the nanowires are studied. The results indicate that uniform Co3O4 nanowires could be synthesized at 90 degrees C, and a transformation of the samples' morphology from nanoparticles to nanowires to microrods is observed by controlling the concentration of the reactants. The well-ordered nanowires synthesized under the selected reaction conditions are composed of spinel Co3O4 with diameters of 500-580 nm and lengths of 6-8 microm. These nanowires show good catalytic activity for the ozone catalytic oxidation of toluene.

Cytochrome b558: the flavin-binding component of the phagocyte NADPH oxidase.

The phagocyte respiratory burst oxidase is a flavin-adenine dinucleotide (FAD)-dependent dehydrogenase and an electron transferase that reduces molecular oxygen to superoxide anion, a precursor of microbicidal oxidants. Several proteins required for assembly of the oxidase have been characterized, but the identity of its flavin-binding component has been unclear. Oxidase activity was reconstituted in vitro with only the purified oxidase proteins p47phox, p67phox, Rac-related guanine nucleotide (GTP)-binding proteins, and membrane-bound cytochrome b558. The reconstituted oxidase required added FAD, and FAD binding was localized to cytochrome b558. Alignment of the amino acid sequence of the beta subunit of cytochrome b558 (gp91phox) with other flavoproteins revealed similarities to the nicotinamide adenine dinucleotide phosphate (reduced) (NADPH)-binding domains. Thus flavocytochrome b558 is the only obligate electron transporting component of the NADPH oxidase.

Delineation of the phagocyte NADPH oxidase through studies of chronic granulomatous diseases of childhood.

The phagocyte NADPH oxidase is a complex system consisting of membrane and cytosolic components that must assemble at the membrane for proper activation. Studies of patients with chronic granulomatous diseases of childhood have enabled the molecular characterization of these components, which has led to studies defining their interaction during NADPH complex assembly. Understanding NADPH oxidase assembly provides an opportunity to develop therapeutics for the regulation of this important reaction of inflammation.

Potential use of a combined ozone and zeolite system for gaseous toluene elimination.

This study investigated the performance of a combined ozone and zeolite system in eliminating gaseous toluene which is a major contaminant in many industrial and indoor environments. The hypothesis that the removal of toluene by ozone can be substantially affected by confining the oxidation reaction in a zeolite structure was evaluated. The degradation of toluene seemed to be contributed by the active oxygen atom generated from the decomposition of ozone at the Lewis acid sites in the zeolite 13X. Air containing toluene levels at 1.5, 2 and 3 ppm was injected with ozone in the range of 0-6 ppm before being vented into a fixed amount of 3600 g zeolite 13X with 90 mm bed-length. The experimental results showed that the elimination rate of toluene was significantly enhanced when compared to using zeolite or ozone alone. In particular, over 90% of the 1.5 ppm toluene was removed when 6 ppm ozone was used at 40% relative humidity level. Deactivation of the zeolite 13X after a few hours of reactions under the current experimental conditions was probably due to the adsorbed water, carbon dioxide and the reaction by-products. The residue species left in the zeolite and the intermediate species in the exhaust gas stream were characterized by FT-IR, GC-MS and HP-LC methods, respectively. A distinctive peak of O atom attached to the Lewis acid site at 1380 cm(-1) was found in the FT-IR spectrum and trace amount of aldehydes was found to be the reaction by-products.

Antagonism of concanavalin A capping in phorbol ester-activated lymphocytes by calmodulin inhibitors and certain amino acid esters.

12-O-Tetradecanoylphorbol-13-acetate (TPA), an effective tumor promoter in mouse skin and comitogen in bovine lymphocytes, rapidly stimulates concanavalin A-mediated cap formation in the latter cells. The ability of different phorbol derivatives to facilitate the capping reaction correlates well with their potencies as lymphocyte comitogens and as tumor-promoting agents. This effect of TPA on capping in bovine lymphocytes, which is apparent within min, is neither mimicked nor altered by dibutyryl cyclic adenosine 3':5'-monophosphate or cyclic guanosine 3':5'-monophosphate. Cytochalasin D, a microfilament-disrupting agent, inhibits cap formation, thereby suggesting the participation of microfilaments in the response. Benzoyl tyrosine ethyl ester selectively inhibits the TPA-stimulated cap formation, whereas benzoyl tyrosinamide is inactive. A comparison of related amino acid derivatives reveals that their activities are dependent on the nature of both the amino acid side chain and the carboxyl end blocking group. Trifluoperazine and N-(6-aminohexyl)-5-chloronaphthalenesulfonamide, known inhibitors of the calmodulin-dependent processes, also selectively block the TPA-stimulated cap formation, whereas trifluoperazine sulfoxide, a less effective calmodulin antagonist, is relatively inactive. These data suggest that the stimulation of capping by TPA involves the activation of a calmodulin-dependent process which may also be regulated by the function of an esterase.

Effects of hexachlorocyclohexane isomers on concanavalin A 'capping' in bovine lymphocytes.

The effects of alpha, beta, gamma, and delta isomers of hexachlorocyclohexane on concanavalin A 'capping' in bovine lymphocytes were evaluated, gamma and delta hexochlorocyclohexane inhibited 'capping' whereas the alpha and beta isomers were without effect. In addition, gamma-hexachlorocyclohexane has been shown to antagonize the maintenance of preformed 'caps' and cause the rapid dispersal of the concanavalin A-receptor complexes over the surface of cells by a temperature-dependent mechanism. The possible role of a gamma-hexachlorocyclohexane-sensitive process in the organization of microflow patterns in the lectin-activated lymphocyte membrane is discussed.

Intracoronary delivery of adenovirus encoding adenylyl cyclase VI increases left ventricular function and cAMP-generating capacity.

BACKGROUND: We tested the hypothesis that intracoronary injection of a recombinant adenovirus encoding adenylyl cyclase type VI (AC(VI)) would increase cardiac function in pigs. METHODS AND RESULTS: Left ventricular (LV) dP/dt and cardiac output in response to isoproterenol and NKH477 stimulation were assessed in normal pigs before and 12 days after intracoronary delivery of histamine followed by intracoronary delivery of an adenovirus encoding lacZ (control) or AC(VI) (1.4x10(12) vp). Animals that had received AC(VI) gene transfer showed increases in peak LV dP/dt (average increase of 1267+/-807 mm Hg/s; P=0.0002) and cardiac output (average increase of 39+/-20 mL. kg(-1). min(-1); P<0.0001); control animals showed no changes. Increased LV dP/dt was evident 6 days after gene transfer and persisted for at least 57 days. Basal heart rate, blood pressure, and LV dP/dt were unchanged, despite changes in cardiac responsiveness to catecholamine stimulation. Twenty-three hour ECG recordings showed no change in mean heart rate or ectopic beats and no arrhythmias. LV homogenates from animals receiving AC(VI) gene transfer showed increased AC(VI) protein content (P=0.0007) and stimulated cAMP production (P=0.0006), confirming transgene expression and function; basal LV AC activity was unchanged. Increased cAMP-generating capacity persisted for at least 18 weeks (P<0.0002). CONCLUSIONS: Intracoronary injection of a recombinant adenovirus encoding AC provides enduring increases in cardiac function.

Removal of batteries from solid waste using trommel separation.

This paper describes the design and testing of a trommel for separation of batteries from solid waste. A trommel is a cylindrical separation device that rotates and performs size separation. It has also been used in areas such as municipal solid waste (MSW) processing, classifying construction and demolition debris, screening mass-burn incinerator ash and compost processing. A trommel has been designed based on size separation to separate household batteries from solid waste, which can then be used as feedstock for alternative applications of solid waste combustion, particularly where the metal content of the product is also a critical parameter, such as the Co-Co process for integrated cement and power production. This trommel has been tested with batches of university office and restaurant wastes against various factors. The recovery efficiency of batteries increases with decreasing inclination angle of the trommel and decreasing rotational speed. A physical characterization of the university solid waste has been performed with a 20-kg sample of the tested waste. It was found that there is a trend of decreasing recovery of batteries with increasing paper composition, and a trend of increasing recovery of batteries with increasing organic materials composition.

Pharmacologic induction of weight loss to treat type 2 diabetes.

OBJECTIVE: Most individuals with type 2 diabetes are overweight, and weight loss for them is an important therapeutic objective. However, usual weight-loss strategies have generally not produced sustained weight loss. Pharmacologic agents to assist weight loss might be useful, but no long-term data on their effectiveness and safety in patients with type 2 diabetes are available. We therefore initiated a 2-year placebo-controlled trial of the weight-loss medications fenfluramine and phentermine in type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: A total of 44 overweight (> 120% ideal body weight) subjects with type 2 diabetes were enrolled in a randomized, placebo-controlled, double-blind trial of fenfluramine and phentermine. All subjects received intensive nutrition counseling, an exercise prescription, and instruction in behavior modification. Subjects were randomly assigned to 20 mg fenfluramine three times a day and 37.5 mg phentermine daily (n = 23) or dual placebos (n = 21). Diabetes medications were adjusted as necessary to achieve glycemic goals. Changes in weight, glycemia, lipemia, and blood pressure were assessed every 2 months, as were adverse events. In September 1997, when fenfluramine was withdrawn from the U.S. market, fenfluramine was stopped in all subjects. Thus the length of drug treatment varied, but 16 subjects (8 in each group) reached 12 months of treatment. Only data obtained before the withdrawal of fenfluramine are included in this report. RESULTS: A study termination, diabetes medications had been reduced in 1 subject in the placebo group (5%) and 11 subjects in the drug treatment group (52%) (P = 0.005). Drug treatment resulted in significant reductions in body weight, BMI, and HbA1c at all time points through 6 months. Changes in weight at 6 months were -2.7 +/- 1.4 kg (mean +/- SEM) with placebo treatment and -9.6 +/- 1.5 kg with drug treatment (P = 0.003). Even though more subjects in the drug treatment group required reductions in diabetes medications, at 6 months, changes in HbA1c were -0.3 +/- 0.2% with placebo treatment and -1.6 +/- 0.3% with drug treatment (P = 0.002). Fasting plasma glucose and triglycerides were significantly reduced at some time points with drug treatment. No serious adverse events attributable to study medications were observed. CONCLUSIONS: Premature study termination decreased the power of our study at later time points. However, our data suggest that weight loss medications are an effective treatment for type 2 diabetes during active weight loss. Whether the benefit persists after weight loss has stopped remains to be determined.

Chronic treatment with phentermine combined with fenfluramine lowers plasma serotonin.

As expected on the basis of published research in both humans and animals, treatment with phentermine/fenfluramine lowers plasma 5-hydroxytryptamine [corrected], whereas treatment with phentermine had no significant effect. In light of these findings, future research should focus on mechanisms other than increased plasma 5-hydroxytryptamine [corrected] to explain how fenfluramine increases the risk of primary pulmonary hypertension and valvular heart disease.

Inhibitors of mammalian melanocyte tyrosinase: in vitro comparisons of alkyl esters of gentisic acid with other putative inhibitors.

To discover safe and effective topical skin-lightening agents, we have evaluated alkyl esters of the natural product gentisic acid (GA), which is related to our lead compound methyl gentisate (MG), and four putative tyrosinase inhibitors, utilizing mammalian melanocyte cell cultures and cell-free extracts. Desirable characteristics include the ability to inhibit melanogenesis in cells (IC50 < 100 microg/mL) without cytotoxicity, preferably due to tyrosinase inhibition. Of the six esters synthesized, the smaller esters (e.g. methyl and ethyl) were more effective enzyme inhibitors (IC50 approximately 11 and 20 microg/mL, respectively). For comparison, hydroquinone (HQ), a commercial skin "bleaching" agent, was a less effective enzyme inhibitor (IC50 approximately 72 microg/mL), and was highly cytotoxic to melanocytes in vitro at concentrations substantially lower than the IC50 for enzymatic inhibition. Kojic acid was a potent inhibitor of the mammalian enzyme (IC50 approximately 6 microg/mL), but did not reduce pigmentation in cells. Both arbutin and magnesium ascorbyl phosphate were ineffective in the cell-free and cell-based assays. MG at 100 microg/mL exhibited a minimal inhibitory effect on DHICA oxidase (TRP 1) and no effect on DOPAchrome tautomerase (TRP-2), suggesting that MG inhibits melanogenesis primarily via tyrosinase inhibition. MG and GA were non-mutagenic at the hprt locus in V79 Chinese hamster cells, whereas HQ was highly mutagenic and cytotoxic. The properties of MG in vitro, including (1) pigmentation inhibition in melanocytes, (2) tyrosinase inhibition and selectivity, (3) reduced cytotoxicity relative to HQ, and (4) lack of mutagenic potential in mammalian cells, establish MG as a superior candidate skin-lightening agent.

Solubilization of hydroxyapatite crystals by murine bone cells, macrophages and fibroblasts.

Calcium phosphate ceramic is widely used as implant material. It is made up of hydroxyapatite, beta-tricalcium phosphate or various combinations of both. In the present study, we use an in vitro model to examine the role of cell-mediated resorption of calcium phosphate ceramic implant material. We compare the abilities of two sequential enzymatic released populations of bone cells from murine calvaria (Population II and Population V), macrophages and dermal fibroblasts to solubilize 45Ca-labelled hydroxyapatite crystals. These crystals were incubated with each of the cell types for 24 h in the presence or absence of parathyroid hormone, prostaglandin E2, calcitonin, and 1,25-dihydroxyvitamin D3. The amount of cell-mediated hydroxyapatite solubilization was determined by measuring the radioactivity in an aliquot of the supernatant after centrifugation. Using dermal fibroblasts as a baseline, relative abilities of macrophages, Population II and Population V to degrade crystals were 10.5, 5 and 2 times that of fibroblasts. Crystal-cell contact was required. While none of the bone resorption agents tested had any effect on this process, crystal dissolution by bone cells was inhibited by two lysosomotropic agents, NH4Cl and chloroquine.

Performance analysis of the bidirectional associative memory and an improved model from the matched-filtering viewpoint.

This paper discusses the bidirectional associative memory (BAM) model from the matched-filtering viewpoint and offers it a new interpretation. Our attention is focused on the problem of stability and attractivity of equilibrium states. Several sufficient and/or necessary conditions are presented. To improve the BAM performance, an exponential function is used to enhance the correlations between the binary vectors of the retrieval key and that of the stored pattern similar to the key. The modified model is shown to be asymptotically stable. Theoretical analysis and simulation results demonstrate that the modified model performs much better than the original BAM in terms of memory capacity and error correction capability.

Some efficient strategies for improving the eigenstructure method in synthesis of feedback neural networks.

Two efficient strategies are proposed for improving the eigenstructure method from the best approximation projector point of view. Interpreted as two complementary best approximation projectors, the method is reformulated in a much more simplified form. We develop a new synthesis procedure through constructing the related best approximation projectors by using a simple recursive formula, which improves on the existing eigenstructure method not only in the significant reduction of the computational complexity but also in the incorporation of the learning capability comparable to the outer product method. The networks designed by the present procedure outperform those designed by some other known methods. We also propose a new forgetting algorithm for deleting any specific existing memories in a synthesized network. The algorithm performs efficiently and reliably, which particularly eliminates the overforgetting drawback of the Yen-Michel algorithm (1991, 1992). The feasibility and effectiveness of the algorithm are supported by theoretical analysis and computer simulations.

A competitive associative memory model and its dynamics.

Conventional associative memory networks perform "noncompetitive recognition" or "competitive recognition in distance". In this paper a "competitive recognition" associative memory model is introduced which simulates the competitive persistence of biological species. Unlike most of the conventional networks, the proposed model takes only the prototype patterns as its equilibrium points, so that the spurious points are effectively excluded. Furthermore, it is shown that, as the competitive parameters vary, the network has a unique stable equilibrium point corresponding to the winner competitive parameter and, in this case, the unique stable equilibrium state can be recalled from any initial key.