Library

Notes: Background:  Breath odour is a complaint encountered worldwide, often linked to microbial overload in the oral cavity. This double blind, crossover, randomised study assessed the efficacy of several antiseptic mouthrinses or slurry vs. a control solution in the prevention of morning bad breath during an experimental period of 7 days without mechanical plaque control. Methods: Sixteen dental students with a healthy periodontium abolished, after a thorough professional cleaning, all means of mechanical plaque control during five experimental periods of 7 days, interleaved by washout periods of at least 3 weeks. During each experimental period, as the only oral hygiene measure, the students rinsed twice a day with one of the following formulations (in a randomised order): a 0.2% chlorhexidine-alcohol mouthrinse (CHX-Alc), a 0.05% CHX + 0.05% cetylpyridinium chloride + 0.14% zinc lactate mouthrinse (CHX-CPC-Zn), an amine fluoride/stannous fluoride (125 ppm F–/125 ppm F–) containing mouthrinse (AmF/SnF2Mr), a slurry of a tooth paste (AmF/SnF2Sl) containing amine fluoride (350 ppm F–) and stannous fluoride (1050 ppm F–) and a placebo solution (placebo). At days 0, 3 and 7, morning breath was scored via VSC level measurements of the mouth air, and organoleptic ratings of the mouth air and tongue coating. At the same visits both the degree of gingival inflammation and the de novo plaque formation were rated. At the end of each period a questionnaire for subjective ratings was completed and microbiological samples were taken from the tongue dorsum, the saliva and the supragingival plaque for anaerobic and aerobic culturing. Results: Although oral hygiene during the experimental periods was limited to rinsing, bad breath parameters systematically improved (P 〈 0.001) with the three mouthrinses (CHX-Alc, CHX-CPC-Zn, AmF/SnF2Mr), with a superiority of the CHX-CPC-Zn solution when only VSC values were considered (P 〈 0.003). The AmF/SnF2 slurry and the placebo solution showed only minor changes with time. The three mouthrinses reduced significantly (P 〈 0.001) the bacterial load (aerobic & anaerobic) in the saliva (≥ 0.5 log reduction with a superiority (P 〈 0.005) for the CHX-Alc when compared to the two others). Changes in the bacterial load on the tongue dorsum could only be detected for the CHX-Alc solution (0.5 log). The antibacterial effect of the placebo solution and the slurry were negligible. The composition of microflora on the other hand did not reveal significant changes. The de novo supragingival plaque formation was significantly (P 〈 0.05) inhibited by the three mouthrinses with a slight superiority for the CHX-Alc solution. The degree of gingival inflammation at day 7 remained low (〈 0.16) for all products. The CHX-Alc solution scored significantly worse for the subjective evaluation (questionnaires) concerning taste and sensitivity of tongue).Conclusions:  The results of this study demonstrate that morning breath odour can be successfully reduced by the sole twice daily use of CHX-Alc, CHX-CPC-Zn or AmF/SnF2Mr mouthrinses, which all significantly reduced the bacterial load in the saliva and retarded the de novo plaque formation.

Notes: Based on a closed surface of triangles fitted to atomic coordinates determined crystallographically, Brune and Kim [Proc. Natl. Acad. Sci. USA 90, 3835–3839 (1993)] proposed a boundary-element Stokes-flow technique for ab initio computation of a translational diffusion coefficient and the rotational diffusion tensor Dr of globular proteins. They applied their approach to atomic coordinates for a tetragonal structure of hen egg-white lysozyme, and reported that computed values of a translational diffusion coefficient and Dr=tr(Dr)/3 agreed well with experiment. After establishing the identity between the infinite-dilution tracer diffusion coefficient of the protein macroion (D+ for lysozyme cation) and the "translational diffusion coefficient" computed by Brune and Kim, we adopt a somewhat different computational approach and show how convergence of D+ and Dr for tetragonal lysozyme depends on two computational parameters characterizing the fidelity of the geometric approximation to the protein surface and two others characterizing the accuracy of the Stokes-flow computations. We then compute D+ and Dr for lysozyme using atomic coordinates for the triclinic crystal structure, three structures determined by nuclear magnetic resonance spectroscopy in the liquid phase (presumably corresponding more closely to in vivo structures), the solvated tetragonal structure (with 108 water molecules) considered by Brune and Kim, and a "dry" version of the same structure. These computations show that D+ and Dr computed for all of the dry crystal structures are in excellent agreement with those for the liquid-phase conformations. Values of D+ and Dr computed for the solvated structure are lower, consistent with the larger volume and area of the corresponding polyhedral surface. We also show that several choices of the origin of the force system [discussed by Brenner, J. Colloid Interface Sci. 23, 407–436 (1967)] give rise to nearly identical translational diffusion coefficients. Finally, we show how to estimate the thickness of the "solvation shell" contributing to the hydrodynamic resistance of the protein cation, and use the binary Nernst–Hartley equation to then estimate the effective cation charge at the two pH values at which the binary diffusion coefficient has been accurately measured in recent interferometric experiments. © 2002 American Institute of Physics.

Notes: Microstructural development in the interface region of α-Al2O3 bilayer composites has been systematically investigated in terms of the sintering additive CaO–SiO2, residual impurity level in the starting powders (particularly MgO), and sintering conditions. The interfacial microstructure is strongly related to relative CaO–SiO2 doping levels in the two constituting layers and to residual impurities in the starting powders. The presence of high levels of impurities in the starting powder can substantially modify the features of CaO–SiO2-Al2O3 liquid at the interface region, thereby strongly influencing α-Al2O3 grain growth across the interface. Three grain growth modes in the interface region thus have been identified for different combinations of impurity level and CaO–SiO2 dopant in the α-Al2O3 bilayer. This provides an important mechanism for controlling two-dimensional structures in coatings, films, and layered ceramic materials for various engineering applications.

Notes: Quality of life (QOL) has recently become one of the most important focuses in oncology nursing practice and research. The aims of this study were to evaluate the QOL in Chinese cancer patients under chemotherapy and to explore the discrepancy between patients’ and nurses’ assessments of the patients’ conditions. The study participants included gestational trophoblastic disease patients (n = 68), ovarian cancer patients (n = 105), patients with other gynaecological cancer (n = 18), and their attending nurses (n = 25) at hospitals affiliated with universities in Beijing. The high level of some symptom subscales/items in patients suggested that innovative and more effective interventions should be developed and utilised in nursing practice. Patients with metastasis reported lower levels of QOL than those without metastasis. The nurses in this study tended to estimate the patients’ QOL inaccurately, except for a few objective aspects. The results of this study can help nurses in planning interventions to enhance the QOL of patients with gynaecological cancer undergoing chemotherapy. The nurses need to be trained to become more sensitive and competent in assessing patients’ subjective information.

Notes: Abstract Purpose. Small solutes which are deposited in the alveoli by aerosolinhalation will be absorbed across the alveolo-capillary barrier.Inhalation of dioctyl sodium sulfosuccinate (DOSS) enhances absorptionwhile having little or no effect on lung function, suggesting that surfaceactive agents may be used as enhancers of alveolar absorption ofinhaled pharmaceuticals. The purpose of this study was to examinethe effects of a selection of different surface active agents onalveolar absorption. Methods. The absorption of 99mTc-diethylene triamine pentaacetate(99mTc-DTPA) from the lungs was studied in rabbits. We studied fivedifferent surface active agents: DOSS, sodium glycodioxycholate(GDCA), sodium lauryl sulphate (NaLS), lysophosphatidyl choline(LPC) and polyoxyethylene-23-laurylether (P23LE). Results. DOSS and GDCA both dramatically enhanced the absorptionof 99mTc-DTPA. There was a moderate effect of NaLS, no significanteffect of LPC and P23LE reduced the rate of absorption. None of thecompounds affected gas exchange or lung compliance. Conclusions. There is a wide spectrum of effects of inhaled surfaceactive agents on the alveolar absorption of 99mTc-DTPA. Ioniccompounds such as DOSS and GDCA have the greatest effect, and furtherstudies of these classes of surface active agents for use as enhancersof alveolar absorption of pharmaceuticals seem warranted.

Notes: Abstract. Mesoscopic transport through an ultrasmall quantum dot (QD) coupled to two single-wall carbon nanotube (SWCN) leads under microwave fields (MWFs) is investigated by employing the nonequilibrium Green’s function (NGF) technique. The charging energy and junction capacitances influence the output characteristics sensitively. The MWFs applied on the leads and gate induce novel photon-assisted tunnelling, strongly associated with the density of states (DOS) of the SWCN leads. The SWCN leads act as quantum wires, and the compound effect induces nonlinear current behavior and resonant tunnelling in a larger region of energy scale. Negative differential conductance (NDC) is clearly observed, as the source-drain junction capacitances C L , and C R are large enough. The multi-resonant NDC oscillation appears due to the charging and photon-electron pumping effects associated with the contribution of multi-channel quantum wires.

Notes: Abstract. Starting from the standard truncated Painlevé expansion and a multilinear variable separation approach, a quite general variable separation solution of the (2+1)-dimensional (M+N)-component AKNS (Ablowitz–Kaup–Newell–Segur) system is derived. In addition to the single-valued localized coherent soliton excitations like dromions, breathers, instantons, peakons, and a previously revealed chaotic localized solution, a new type of multi-valued (folded) localized excitation is obtained by introducing some appropriate lower-dimensional multiple valued functions. The folded phenomenon is quite universal in the real natural world and possesses quite rich structures and abundant interaction properties.

Notes: Abstract: The ac Stark effect is investigated in the toroidal carbon nanotube system threaded with an ac magnetic flux. The Floquet theory is employed to deal with the time-dependent quantum problems. The time-averaged energy of the system is derived and is found to exhibit a strong relationship with an external field, and the modified energy gap has been presented. The ac flux enhances energy gaps to cause metal-semiconductor transition. The steady current has been obtained by employing the free energy approach, and the persistent current is a special case as the magnitude of the ac flux approaches zero. The photon-assisted current is quite different from the persistent current due to the absorption and emission of photons. The local density of states is obtained by calculating the Green's function in the Floquet state, and photon-resonant structures are observed. All of the novel features are associated with the ac Stark effect, which is caused by the modification of energy levels.

Notes: Abstract The majority of quality of life (QOL) questionnaires have been developed and used in English-speaking or Western European countries. The aims of this study were to provide the Standard Chinese version of the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30 version 2.0), and evaluate its psychometric properties. The translation process included independent translation, back translation, a pilot test with gynecological cancer patients, and a review and approval by the original developers. Participants in the major study included gestational trophoblastic disease patients (n = 68), ovarian cancer patients (n = 105), and other types of gynecological cancer patients (n = 18). The average completion time of the Standard Chinese version was 8.1 ± 2.9 min. All item-subscale correlation coefficients exceeded the criterion of item-convergent validity (r 〉 0.40) except item 1, 5, 20, and 25, and all items correlated significantly higher with their own subscale than with other subscales except item 1, 20, and 25. The correlation coefficients among all subscales were significant but modest (r = 0.40–0.70). Seven out of nine subscales met the minimal standards of reliability (Cronbach's α 〉 0.70). In conclusion, the Standard Chinese version of the EORTC QLQ-C30 is a valid instrument overall in assessing the QOL of Chinese gynecological cancer patients.