An E-Nose for the Monitoring of Severe Liver Impairment: A Preliminary Study

Biologically inspired to mammalian olfactory system, electronic noses became popular during the last three decades. In literature, as well as in daily practice, a wide range of applications are reported. Nevertheless, the most pioneering one has been (and still is) the assessment of the human breath composition. In this study, we used a prototype of electronic nose, called Wize Sniffer (WS) and based it on an array of semiconductor gas sensor, to detect ammonia in the breath of patients suffering from severe liver impairment. In the setting of severely impaired liver, toxic substances, such as ammonia, accumulate in the systemic circulation and in the brain. This may result in Hepatic Encephalopathy (HE), a spectrum of neuro-psychiatric abnormalities which include changes in cognitive functions, consciousness, and behaviour. HE can be detected only by specific but time-consuming and burdensome examinations, such as blood ammonia levels assessment and neuro-psychological tests. In the presented proof-of-concept study, we aimed at investigating the possibility of discriminating the severity degree of liver impairment on the basis of the detected breath ammonia, in view of the detection of HE at its early stage.

Upconversion Nanoprobes for in Vitro and ex Vivo Measurement of Carbon Monoxide

Here, we have developed a new colorimetric and luminescence nanosensor, based on upconversion nanoparticles (UCNPs), for in vitro and ex vivo measurement of carbon monoxide (CO). The nanoprobe has two strong fluorescence emission peaks in the UCNP core to excite fluorophores at 540 and 800 nm. The CO-responsive palladium ion-bounded rhodamine B derivatives (Pd-RBDs) are encapsulated in the mesoporous silica (mSiO₂) shell and the particles outside the cyclodextrin (CD) layer. Reduction of palladium ions by CO results in the release of palladium from the Pd-RBDs, thereby inducing the closure of the spiro ring of the RBD and the accompanying reduction of rhodamine B (RB) absorption at 500-600 nm overlapping with the luminescence spectrum of UCNPs maximized at 540 nm. Therefore, the I₅₄₀/I₈₀₀ ratio of the nanoprobe will increase when CO is present, making it possible to quantitatively measure CO. Besides working in a clean buffer environment with known [CO], this method was evaluated using living cells and tissue sections. Additionally, these probes were also successfully used to investigate the CO-related protective activity of anti-hepatic ischemia-reperfusion injury (HIRI) oligopeptides.

A Novel Optimization Technique to Improve Gas Recognition by Electronic Noses Based on the Enhanced Krill Herd Algorithm

An electronic nose (E-nose) is an intelligent system that we will use in this paper to distinguish three indoor pollutant gases (benzene (C₆H₆), toluene (C₇H₈), formaldehyde (CH₂O)) and carbon monoxide (CO). The algorithm is a key part of an E-nose system mainly composed of data processing and pattern recognition. In this paper, we employ support vector machine (SVM) to distinguish indoor pollutant gases and two of its parameters need to be optimized, so in order to improve the performance of SVM, in other words, to get a higher gas recognition rate, an effective enhanced krill herd algorithm (EKH) based on a novel decision weighting factor computing method is proposed to optimize the two SVM parameters. Krill herd (KH) is an effective method in practice, however, on occasion, it cannot avoid the influence of some local best solutions so it cannot always find the global optimization value. In addition its search ability relies fully on randomness, so it cannot always converge rapidly. To address these issues we propose an enhanced KH (EKH) to improve the global searching and convergence speed performance of KH. To obtain a more accurate model of the krill behavior, an updated crossover operator is added to the approach. We can guarantee the krill group are diversiform at the early stage of iterations, and have a good performance in local searching ability at the later stage of iterations. The recognition results of EKH are compared with those of other optimization algorithms (including KH, chaotic KH (CKH), quantum-behaved particle swarm optimization (QPSO), particle swarm optimization (PSO) and genetic algorithm (GA)), and we can find that EKH is better than the other considered methods. The research results verify that EKH not only significantly improves the performance of our E-nose system, but also provides a good beginning and theoretical basis for further study about other improved krill algorithms’ applications in all E-nose application areas.

A microfluidic cigarette smoke collecting platform for simultaneous sample extraction and multiplex analysis

In this work, we report a novel microfluidic gas collecting platform aiming at simultaneous sample extraction and multiplex mass spectrometry (MS) analysis. An alveolar-mimicking elastic polydimethylsiloxane (PDMS) structures was designed to move dynamically driven by external pressure. The movement was well tuned both by its amplitude and rhythm following the natural process of human respiration. By integrating the alveolar units into arrays and assembling them to gas channels, a cyclic contraction/expansion system for gas inhale and exhale was successfully constructed. Upon equipping this system with a droplet array on the alveolar array surface, we were able to get information of inhaled smoke in a new strategy. Here, with cigarette smoke as an example, analysis of accumulation for target molecules during passive smoking is taken. Relationships between the breathing times, distances away from smokers and inhaled content of nicotine are clarified. Further, by applying different types of extraction solvent droplets on different locations of the droplet array, simultaneous extraction of nicotine, formaldehyde and caproic acid in sidestream smoke (SS) are realized. Since the extract droplets are spatially separated, they can be directly analyzed by MS which is fast and can rid us of all complex sample separation and purification steps. Combining all these merits, this small, cheap and portable platform might find wide application in inhaled air pollutant analysis both in and outdoors.

SnO2 highly sensitive CO gas sensor based on quasi-molecular-imprinting mechanism design

Response of highly sensitive SnO₂ semiconductor carbon monoxide (CO) gas sensors based on target gas CO quasi-molecular-imprinting mechanism design is investigated with gas concentrations varied from 50 to 3000 ppm. SnO₂ nanoparticles prepared via hydrothermal method and gas sensor film devices S_C (exposed to the target gas CO for 12 h after the suspension coating of SnO₂ film to be fully dried, design of quasi-molecular-imprinting mechanism, the experiment group) and S_A (exposed to air after the suspension coating of SnO₂ film to be fully dried, the comparison group) made from SnO₂ nanoparticles are all characterized by XRD, SEM and BET surface area techniques, respectively. The gas response experimental results reveal that the sensor S_C demonstrates quicker response and higher sensitivity than the sensor S_A does. The results suggest that in addition to the transformation of gas sensor materials, surface area, and porous membrane devices, the Molecular Imprinting Theory is proved to be another way to promote the performance of gas sensors.

Low temperature activation of CO removal by O3-assisted catalysis

Catalytic CO oxidation was activated at low temperature by injecting O3 as an additive. It was empirically confirmed that CO removal rate was dramatically enhanced by supplying a small amount of O3, and the reaction temperature was almost half that required for CO oxidation when using a catalyst only. By optimizing the concentration of O3, catalytic CO oxidation could be achieved within 1 min at low operational temperature. The removal rate of CO was sensitive to the concentration of O3, and a deduced reaction mechanism is discussed to explain how catalytic CO oxidation is activated but subsequently deactivated at higher O3 concentration. Moreover, the presence of C3H8 and C3H6 were considered to evaluate the effects of each gas on the enhancement of CO removal rate by O3. Finally, the rate of CO removal was evaluated with increasing O3 concentration for practical applications such as the cold-start problem in automobile engines.

The etymological role of the main atmosphere pollutants in development of human diseases

The aim of research was monitoring of the main atmospheric air pollutants concentration on Adjara Autonomous Republic territory in order to determine their role in causing different diseases. The following atmospheric air pollutants have been determined in Batumi: dust, carbon monoxide, sulfur and nitrogen dioxide. The number of diseases registered in Adjara Autonomous Republic, which may be linked to the air pollution, has been studied. These are the following: chronic and nonspecific bronchitis, asthma and asthma status diseases, allergic rhinitis, trachea-, bronchi- and lung malignant tumor. In order to reduce the number of risk-factors significant attention should be paid to the proper functionality of the vehicles and systematic observations should continue on the chemical pollution of the air to make proper decisions to reduce the number of diseases.

CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles

Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors.

Catalytic removal of carbon monoxide over carbon supported palladium catalyst

Carbon supported palladium (Pd/C) catalyst was prepared by impregnation of palladium chloride using incipient wetness technique, which was followed by liquid phase reduction with formaldehyde. Thereafter, Pd/C catalyst was characterized using X-ray diffractometery, scanning electron microscopy, atomic absorption spectroscopy, thermo gravimetry, differential scanning calorimetry and surface characterization techniques. Catalytic removal of carbon monoxide (CO) over Pd/C catalyst was studied under dynamic conditions. Pd/C catalyst was found to be continuously converting CO to CO(2) through the catalyzed reaction, i.e., CO+1/2O(2)→CO(2). Pd/C catalyst provided excellent protection against CO. Effects of palladium wt%, CO concentration, humidity, space velocity and reaction environment were also studied on the breakthrough behavior of CO.

A method for screening the potential of MOFs as CO2 adsorbents in pressure swing adsorption processes

This work reports the adsorption and coadsorption data of CO(2)/CH(4)/CO mixtures on several metal-organic frameworks [MOFs; MIL-100(Cr), MIL-47(V), MIL-140(Zr)-A, Cu-btc, and MIL-53(Cr)] and compares them with reference adsorbents, that is, zeolite NaX and an activated carbon material, AC35. We also evaluate the effect of H(2)O on CO(2) adsorption and on the stability of the structures. Based on the experimental adsorption data, the performance potential of MOFs in several pressure swing adsorption processes is estimated by making a ranking of working capacities and separation factors. We discuss the separation of biogas, the purification of H(2) produced by steam reforming of methane, and the removal of CO(2) from synthesis gas in IGCC (integrated gasification combined cycle) systems. Some MOFs are very well placed in the ranking of (isothermal) working capacity vs. selectivity. Yet, performance is not the only criterion for the selection of MOFs. Ease and cost of synthesis and long-term stability are other important aspects that have to be taken into account.

Modification of red mud by acid treatment and its application for CO removal

Activated red mud (ARM) samples were tested for carbon monoxide (CO) oxidation in the temperature range of 100-500°C. Conversion of >90% was obtained for temperatures above 400°C for all samples. In order to study the effect of hydroxylated phases of iron oxide in red mud on the removal of CO, 'as-received' red mud (RM) and acid digested and re-precipitated red mud (TRM) were also tested under similar conditions. It was found that TRM was more effective in removal of CO with the 50% conversion temperature (T50) 80°C lower than the ARM samples. The samples before and after reaction were characterized by inductively coupled plasma-optical emission spectroscopy (ICP-OES), BET N(2) adsorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), electron microscopy (SEM and TEM) and temperature programmed reduction (TPR). It was observed that TRM had iron in an amorphous form which then converted to iron oxide after heating. The higher activity of TRM was due to its higher surface area and presence of hydroxylated phase of iron oxide.

Recycling of organic materials and solder from waste printed circuit boards by vacuum pyrolysis-centrifugation coupling technology

Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30 min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400-600°C, and the rotating drum was rotated at 1000 rpm for 10 min. The type-A of WPCBs pyrolysed to form an average of 67.91 wt.% residue, 27.84 wt.% oil, and 4.25 wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22 wt.% residue, 21.57 wt.% oil, and 6.21 wt.% gas. The GC-MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO(2), CH(4), and H(2), which could be collected and recycled.

Removal of NOx and CO from a burner system

This paper presents the development of an emissions-controlling technique for oil burners aimed especially to reduce oxides of nitrogen (NOx). Another emission of interest is carbon monoxide (CO). In this research, a liquid fuel burner is used. In the first part, five different radial air swirler blade angles, 30 degrees , 40 degrees , 45 degrees , 50 degrees , and 60 degrees , respectively, have been investigated using a combustor with 163 mm inside diameter and 280 mm length. Tests were conducted using kerosene as fuel. Fuel was injected at the back plate of the swirler outlet. The swirler blade angles and equivalence ratios were varied. A NOx reduction of more than 28% and CO emissions reduction of more than 40% were achieved for blade angle of 60 degrees compared to the 30 degrees blade angle. The second part of this paper presents the insertion of an orifice plate at the exit plane of the air swirler outlet. Three different orifice plate diameters of 35, 40, and 45 mm were used with a 45 degrees radial air swirler vane angle. The fuel flow rates and orifice plate's sizes were varied. NOx reduction of more than 30% and CO emissions reduction of more than 25% were obtained using the 25 mm diameter orifice plate compared to the test configuration without the orifice plate. The last part of this paper presents tests conducted using the air-staging method. An industrial oil burner system was investigated using the air staging method in order to reduce emission, especially NOx. Emissions reduction of 30% and 16.7% were obtained for NOx and CO emissions, respectively, when using air staging compared to the non-air-staging tests.

Optimization of the treatment of carbon monoxide-polluted air in biofilters

This work is the first extensive study on the removal of carbon monoxide from polluted air in biofilters. It compares the performance of two packing materials, namely lava rock alone and a mixture of peat and lava rock. The results show that the biofilter packed with the mixture of peat and lava rock performed much better than the other one. The effect of operating conditions as, among others, the inlet concentration and the empty bed residence time (EBRT) were studied. A maximum elimination capacity of 33 g m(-3) h(-1) was obtained with the mixed packing with more than 85% removal efficiency at EBRT of 3 min or more. Somewhat lower performances were reached at shorter EBRT. The results presented here suggest that the mixture of lava rock and peat, subject to further optimization, offers potential for the biological removal of CO from polluted gas streams.

Removal of formaldehyde, methanol, dimethylether and carbon monoxide from waste gases of synthetic resin-producing industries

The removal of mixtures of gas-phase pollutants released from formaldehyde- and formaldehyde resin-producing industries was studied in different bioreactor systems. The waste gases contained formaldehyde, methanol, dimethylether and carbon monoxide. The use of a hybrid two-stage bioreactor, composed of a biotrickling filter and a conventional biofilter connected in series, led to very high elimination capacities and removal efficiencies close to 100% for overall pollutant loads exceeding 600g m(-3)h(-1). The presence of low concentrations of dimethylether in the gaseous mixture did not have a significant effect on the removal of formaldehyde or methanol under our operating conditions, although moderate concentrations of these compounds did negatively affect the biodegradation of dimethylether. When a mixture of all four compounds, at concentrations around 100, 100, 50 and 50mg m(-3) for formaldehyde, methanol, carbon monoxide and dimethylether, respectively, was fed to a conventional biofilter, removal efficiencies higher than 80% were obtained for the first three pollutants at empty bed retention time values above 30s. On the other hand, dimethylether was removed to a lower extent, although its reduced environmental impact allows to conclude that these results were satisfactory.

Development and comparisons of efficient gas-cultivation systems for anaerobic carbon monoxide-utilizing microorganisms

We describe a system for the cultivation of gaseous substrate utilizing microorganisms that overcomes some of the limitations of fixed volume culture vessels and the costs associated with sparging. Cali-5-Bond gas-sampling bag was used as the culture vessel. The bags contain approximately six times more mass of CO than the 40 mL vials at 1 atm of pressure and performed equally to the 40 mL vials in terms of their ability to maintain the composition of the gas over extended incubation times. Experiments using Clostridium ljungdahlii and CO as the sole carbon and energy source in both the gas sampling bag cultivation system and the traditional vial system demonstrated that this culture had a 15x increase in optical density in 24 h of incubation. The gas-sampling bags offer a viable alternative to gas sparging while overcoming the limitations of fixed volume culture vessels.

Successful a Priori Modeling of CO Adsorption on Pt(111) Using Periodic Hybrid Density Functional Theory

The adsorption of CO on the surface of metals such as Pt(111) is of great interest owing to the industrial importance of the catalytic oxidation of pollutant CO. To date, reliable high-level calculations of this process have not been possible, a situation often referred to as the "CO/Pt(111) puzzle". Standard generalized-gradient-approximation density functional theory approaches fail to capture key details of the binding, such as the location of the adsorption site, while cluster approaches using alternative methods show some but insufficient improvement. Using a new computational methodology combining hybrid density functionals containing non-local Hartree-Fock exchange with periodic imaging plane-wave-based techniques, we demonstrate that key aspects of the adsorption of CO on Pt(111), including the identification of the absorption site and CO frequency change, can now be adequately modeled. The binding is dominated by both CO dative covalent bonding and metal-to-molecule pi back-bonding, effects requiring realistic alignment of both the molecular HOMO and LUMO orbitals with respect to the metal Fermi energy.

Decomposition of mixed malodorants in a wire-plate pulse corona reactor

Decomposition characteristics of two groups of representative mixed malodorants (1, ethanethiol + hydrogen sulfide; 2, ethanethiol + ammonia) in air were investigated employing a wire-plate pulse corona reactor. A new type of high-voltage pulse generator with a thyratron switch and a Blumlein pulse-forming network (BPFN) was used in our experiments. The experiments were conducted at a gas-flow rate of 13 m3/h. Important parameters, including peak voltage, chemical structures of malodorants, pulse frequency, and initial concentration, which influenced the removal efficiency, were investigated. The results showed that the mixed malodorants could be treated effectively by pulse corona. The removal efficiencies of 200 mg/m3 C2H5SH and 200 mg/m3 H2S for group 1 were 95.6% and 100%, respectively, which were almost equal to those of the two pollutants separately. The energy cost was about 65.1-81.4 J/L, which was 31.5-45.2% lower than for treating pollutants alone. The removal efficiencies of 105 mg/m3 C2HsSH and 40 mg/m3 NH3 for group 2 were 93.1% and almost 100%, and the energy cost was 65.1 J/L, 55.6% lower than that which was treated separately. In the case of two groups of mixed malodorants removal, NOx, 03, SO2, CO2, and CO were all observed. Moreover, some sulfur and white crystal ammonium nitrates were discovered adhering to the corona wires in the removal of groups 1 and 2, respectively. A dynamics model was developed to describe the relation of the removal efficiency with specific energy density and initial concentration. In the case of group 1 removal,the decomposition rate constants decreased as compared to the single treating. As for group 2 removal, the decomposition rate constants increased, especially for NH3. According to the results, the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.

Infrared Spectra of RuTPP, RuCOTPP, and Ru(CO)2TPP Isolated in Solid Argon

Infrared spectra of unstable species such as CO-free ruthenium tetraphenylporphyrin RuTPP and RuCOTPP (species with vacant coordination sites) isolated in solid argon at 8 K have been recorded. Selective deposition conditions allow the isolation of either RuTPP and RuCOTPP or RuCOTPP and Ru(CO)2TPP. This depends on the preparation conditions of the sample. A specific Ru-CO bending mode has been characterized at 590.1 cm(-1) for Ru(CO)2TPP. The behavior of each vibrational mode of RuTPP, RuCOTPP, and Ru(CO)2TPP has been analyzed. Modes such as gamma8 at 721.3 cm(-1) (out-of-plane stretching mode gamma(Cbeta-H)sym) and nu41 at 1342.8 cm(-1) (nuCalpha-N coupled with deltaCalpha-Cm) reflect the charge transfer in the porphyrin. Indeed, the addition of one or two CO ligands to RuTPP reduces the charge transfer between the metal center and the porphyrin, which appears as an increase in the frequency of the nu41 mode and in a decrease in that of the gamma8 mode.

Respiratory health and indoor air pollution at high elevation

In this research, the authors sought to provide experimental data on indoor air quality, and the resulting respiratory impact, for a high-elevation (4550 m), rural community in Ladakh, India. This community is of interest because the primarily nomadic residents burn biomass inside the home for heating and cooking. The concentrations of particulate matter (PM), endotoxin, and carbon monoxide were determined for 6 homes. Lung function data and induced sputum samples were collected for 9 female test-home subjects. In addition, lung function data were collected for 84 additional Ladakhi highlanders at this location. Sputum from 3 visiting scientists (sojourners) was collected and analyzed as well. The average PM concentration ranged from 2 mg/m3 to 7 mg/m3, with 85% of the sampled PM sized as respirable. The average endotoxin concentration ranged from 2.4 ng/m3 to 19 ng/m3, and average carbon monoxide levels ranged from 50 ppm to 120 ppm. Lung function values for the highlander population and the test-home subjects were equal to or greater than predicted, despite the highlanders' significant exposure to indoor pollutants. An induced sputum analysis revealed a significantly greater total inflammatory cell count (M +/- SD, 10(5) cell/mg) in the Ladakhi natives than in the sojourners (107.5 +/- 75.2 vs 7.1 +/- 8.1, p < .01). Although the high levels of indoor pollutants did not correlate with significant decrements in lung function, the induced sputum analysis revealed marked airway inflammation dominated by macrophages and neutrophils. It appears that augmented lung mechanics of this high-altitude population are adaptive to reduce the work of breathing; thus, decrements in lung function go undetected because the true predicted values are greater than expected.

[Recovery of CO from an ammonia plant tail gas with pressure swing adsorption process]

Ammonia plant tail gas is an important CO source for C1 chemistry if an efficient separation/purification technology is available. Presented is pressure swing adsorption using a home made catalyst PU1 for recovery of CO from ammonia plant tail gas. A performance comparison of PU1 with a commercial zeolite was also presented. The pilot plant experiments were carried out in an intermission one-bed PSA unit with ammonia plant tail gas and a feed flow rate of 0.2-0.8 m3/h. The purity and recovery of CO was studied under various operating conditions. The operating conditions for the process were optimized and an optimum cyclic sequence of operation steps was proposed. A good performance of PU1 in the process was experimentally demonstrated. Product gas with a CO purity over 98% could be produced at a CO recovery of 75% for a feed gas CO concentration of 30% and gas pressure of 0.3 MPa.

A remote-controlled high pressure reactor for radiotracer synthesis with [11C]carbon monoxide

[11C]Carbon monoxide is a versatile building block for the synthesis of PET radiotracers. However, the difficulty of trapping [11C]CO in a small solvent volume has limited its utility. We wish to report the details of a simple, remotely operated High Pressure Reactor (HiPR) system for trapping and reacting practical quantities of [11C]CO. All parts used in the HiPR are commercially available, providing an inexpensive and easily assembled system. A number of compounds have been synthesized using the HiPR via palladium mediated reactions with [11C]CO, an aryl halide, and a nucleophile dissolved in dioxane. For example, AMPA receptor modulator [11C]CX546 was synthesized from its respective precursors in 37% isolated yield, uncorrected from trapped [11C]CO.

Randomised trial investigating effect of a novel nicotine delivery device (Eclipse) and a nicotine oral inhaler on smoking behaviour, nicotine and carbon monoxide exposure, and motivation to quit

OBJECTIVE

To monitor the effect of a novel nicotine delivery device that may produce fewer carcinogens (Eclipse) on cigarette smoking, carbon monoxide and nicotine concentrations, and motivation to give up smoking. The smoker's own brand of cigarette and a nicotine replacement product (Nicotrol inhaler) were used as comparisons.

DESIGN

After baseline data were recorded, smokers were randomised to either Eclipse or inhaler for two weeks and then switched to the other product for another two weeks. Thereafter a second baseline was obtained.

SETTING AND PARTICIPANTS

Fifty smokers were included and data are reported for the 40 with complete data sets. The smokers were not trying to quit but were interested in trying a new product to reduce their risk. They visited a smoking clinic 10 times during the six week period of the trial.

INTERVENTION

No counselling to aid reduction by Eclipse or inhaler was given.

MAIN OUTCOME MEASURES

At each visit smoking status and carbon monoxide concentrations were recorded. In half of the visits withdrawal symptoms, attitudes towards smoking, heart rate, and blood nicotine concentrations were also recorded.

RESULTS

Eclipse use decreased the number of cigarettes smoked per day (cpd) from 19.1 cpd at baseline to 2.1 cpd (p < 0.001), but increased carbon monoxide concentrations in parts per million (ppm) from 21.0 ppm to 33.0 ppm (p < 0.001). A similar decrease in cigarettes smoked per day was seen with the Nicotrol inhaler, from 19.1 cpd to 4.8 cpd (p < 0.001), but carbon monoxide decreased from 21.0 ppm to 12.7 ppm (p < 0.001). The blood nicotine concentration remained fairly stable with Eclipse, increasing slightly from 16.8 ng/ml to 18.0 ng/ml, while for the inhaler a significant drop was noted, from 16.8 ng/ml to 12. 2 ng/ml (p < 0.002). Craving and withdrawal did not increase with Eclipse. Few significant adverse events occurred with Eclipse.

CONCLUSIONS

Eclipse can dramatically decrease cigarette consumption without causing withdrawal symptoms or decreases in nicotine concentrations or motivation to quit altogether. Unlike the inhaler, Eclipse produces an increase in carbon monoxide concentration. Thus Eclipse may not be a safer cigarette.

Modulation of the association reaction between hemoglobin and carbon monoxide by proton and chloride

A cryogenic technique for the isolation of the ligation intermediates in the association reaction between hemoglobin and carbon monoxide at 20 degrees C [Perrella, M., Davids, N., and Rossi-Bernardi, L. (1992) J. Biol. Chem. 267, 8744-8751] was used to study the effects of proton and chloride concentrations on the rates of the stepwise reactions. The reaction rate was observed to increase continuously in the course of the ligation process, yet the acceleration of the reaction after the binding of two ligand molecules, observed previously in 100 mM KCl, pH 7, was not observed at other pH values. At pH 6.3, such an acceleration occurred after the binding of three ligands, and at pH 8.5, a large acceleration was observed after the binding of the first ligand molecule. Greater CO binding to the beta chains was observed under all conditions, as in the previous study. The functional heterogeneity of the chains in the first ligation step increased with pH. The chloride concentration did not influence the distribution of the ligand between the alpha and beta chains at pH 6.3 and 8.5. At pH 7, less binding to the alpha chains was observed at 7 mM chloride with respect to 100 mM. The nature of the biliganded component isolated at pH 7 in 100 mM KCl and unresolved by the cryogenic technique was studied using a combination of cryogenic and noncryogenic isoelectric focusing. This component was a mixture of intermediates (alpha beta) (alpha CO beta CO), about 65%, and (alpha beta CO) (alpha CO beta), about 35%. The experimental data were compared with the distributions of intermediates calculated according to the Monod kinetic model assuming rapid and concerted transitions between two quaternary structures at each ligation step. The model provided a qualitative fit of the observed distributions of intermediates at acidic and neutral pH. A large discrepancy between the experimental observations and the predictions of the model was found at alkaline pH. The mechanism of the association reaction is discussed in the light of the available information on the tertiary/quaternary structures of the intermediates, as obtained from the studies of the deoxy/cyanomet model of ligation.

Comparison of smoking behavior change for SI and UC study groups. MRFIT Research Group

BACKGROUND

The results of MRFIT smoking intervention program are presented for the 4,103 special intervention and 4,091 usual care men who reported smoking cigarettes at the first screening visit.

RESULTS

Among the special intervention men, the reported cessation rate increased from 43.1% at 12 months to 48.9% at 72 months. The reported cessation rate among the usual care men increased from 13.5% at 12 months to 28.8% at 72 months. Among smokers who reported cessation at 72 months, 51.3% of special intervention men and 22.7% of usual care men had quit smoking within the first year and remained abstinent thereafter. Average thiocyanate and expired-air carbon monoxide served as objective measures of smoking and were significantly lower among the special intervention men than among the usual care men over the entire follow-up period. The reported cessation rates at 72 months varied according to initial levels of smoking. Smokers reporting 1-19 cigarettes per day at entry were more likely to quit than heavier smokers. For each category of smoking at entry (1-19, 20-39, and 40 or more cigarettes per day) significantly more special intervention than usual care smokers reported cessation.

CONCLUSION

These results indicate that the MRFIT smoking intervention program was successful in promoting early cigarette smoking cessation and maintaining cessation over the entire trial for a large percentage of cigarette smokers.