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  • 1
    Electronic Resource
    Electronic Resource
    Impurity photovoltaic effect: Fundamental energy conversion efficiency limits (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 92 (2002), S. 1329-1336 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the past, minimal improvements have been predicted for efficiency enhancement of solar cells using the impurity photovoltaic (IPV) effect, where optical excitation through midgap defect levels allows the use of long wavelength photons to increase the conversion efficiency of sunlight to electricity. In the present work, the principle of detailed balance is used to calculate the limiting efficiency of solar cells with the inclusion of the impurity photovoltaic effect, in the idealized case when all transitions are assumed to be radiative. Based on these calculations, the limiting efficiency of the IPV device with a large number of different defect species is determined to be 77.2%. The terrestrial performance of the IPV device is also investigated by comparing its spectral sensitivity with that of tandem solar cell designs. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1492016
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  • 2
    Electronic Resource
    Electronic Resource
    Miniaturization and integration of photoacoustic detection (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 92 (2002), S. 1555-1563 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoacoustic spectroscopy is an absorption spectroscopy technique that is currently used for low-level gas detection and catalyst characterization. It is a promising technique for chemical analysis in mesoscale analysis systems because the detection limit scales favorably with miniaturization. This work focuses on the scaling properties of photoacoustic spectroscopy, and on the miniaturization of gas-phase photoacoustic detection of propane in a nitrogen ambient. The detection system is modeled with a transmission line analogy, which is verified experimentally. The model includes the effects of acoustic leaks and absorption saturation. These two phenomena degrade the performance of the photoacoustic detector and must be controlled to realize the scaling advantages of photoacoustic systems. The miniature brass cells used to verify the model employ hearing aid microphones and optical excitation from a mechanically chopped, 3.39 μm He–Ne laser, transmitted into the cells with an optical fiber. These cells are able to detect 10 ppm of propane in nitrogen (a signal level of ∼1 Pa/W). We also describe the development of a miniaturized photoacoustic system formed by microfabrication. In this case, the pressure-driven deflection of the detection membrane is measured optically. These systems show that photoacoustic detection may be inappropriate for systems with large variations in gas concentration because of absorption saturation and changing gas acoustic properties. Nevertheless, photoacoustic spectroscopy is a promising technique for the analysis of dilute mixtures in miniature chemical systems. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1489493
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  • 3
    Electronic Resource
    Electronic Resource
    Congenital multiple clustered dermatofibroma (2000)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 142 (2000), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Multiple clustered dermatofibroma (MCD) is a rare tumour which usually appears during the first and second decades of life. We report a man in whom the MCD was congenital, although during the first few years of his second decade it extended to involve a broad zone on the left hip, gluteal region and upper thigh.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.2000.03494.x
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  • 4
    Electronic Resource
    Electronic Resource
    Emission properties of an amorphous AlN:Cr3+ thin-film phosphor (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1246-1248 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Chromium-doped aluminum nitride (AlN:Cr) films were grown on p-doped silicon (111) by rf magnetron sputtering in a nitrogen atmosphere at a pressure of 10−4 Torr. Film thickness was typically 200 nm. After growth, the films were "activated" at ∼1300 K for 30 min in a nitrogen atmosphere. Films activated in this manner exhibit intense cathodoluminescence and photoluminescence emission. Spectral evidence demonstrates conclusively that the luminescent centers are Cr3+ ions. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1351531
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  • 5
    Electronic Resource
    Electronic Resource
    Chewing ability of subjects with shortened dental arches (2003)
    Oxford, UK : Munksgaard International Publishers
    Community dentistry and oral epidemiology 31 (2003), S. 0 
    Details
    ISSN: 1600-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract  – Objectives:  The objective was to study chewing ability in subjects with shortened dental arches in Tanzania.Methods:  A sample of 725 adults with shortened dental arches comprising intact anterior regions and 0–8 occluding pairs of posterior teeth and 125 adults with complete dental arches were recruited. Subjects were classified into nine categories according to arch length and symmetry. Chewing ability was investigated by interview on chewing complaints and on perceived difficulty of chewing 20 common Tanzanian foods, 12 soft, and 8 hard.Results:  Categories with extreme shortened arches (0–2 pairs of occluding premolars) reported most frequent (95–98%) and most severe complaints (‘cannot chew all foods’ or ‘have to use special or specially prepared food’). Categories with intact premolar regions and at least one occluding pair of molars had nearly no complaints (95–97%). The other arch categories had an intermediate volume of complaints (33–54%). Perceived difficulty of chewing deteriorated with a decrease of occluding pairs of teeth. Subjects with 0–2 pairs of occluding premolars had major difficulties with chewing. Subjects with 3–4 pairs of occluding premolars or asymmetric arches comprising a short side with none or one pair of premolars and a long side including at least one occluding pair of molars had more difficulties with chewing compared to subjects with more complete dental arches. As a whole, they perceived for hard foods, ‘minor problems, not adapted’.Conclusions:  Shortened dental arches with intact premolar regions and at least one occluding pair of molars provide sufficient chewing ability. Shortened arches with 3–4 pairs of occluding premolars and asymmetric arches with a long side result in impairment of chewing ability, especially for hard foods. In extremely shortened arches comprising 0–2 occluding premolars, chewing ability is severely impaired.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0528.2003.t01-1-00011.x
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  • 6
    Electronic Resource
    Electronic Resource
    Emergence of permanent teeth in Tanzanian children (2002)
    Oxford, UK : Munksgaard International Publishers
    Community dentistry and oral epidemiology 30 (2002), S. 0 
    Details
    ISSN: 1600-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract –Objective:  The aim of the present study was to investigate the emergence of permanent teeth among Tanzanian children.Methods: A total of 869 Tanzanian children were recruited from 16 schools in age groups 3.5–5, 6.5–8, 9.5–11 and 15–16 years of whom 428 (49%) were boys and 441 (51%) were girls. The effects of age and gender on the emergence stages of the dentition were determined for the four age groups.Results: Girls, but not boys, had some permanent maxillary canines, second premolars and mandibular and maxillary second molars as early as at the age of 6.5–8 years. Permanent teeth of both the first and the second transitional periods were already emerging at the age of 3.5–5 years and 6.5–8 years, respectively. At 3.5–5 years, 9% of the permanent teeth belonging to the first transitional period were already in occlusion. Emergence of incisors and first molars was more advanced in girls than in boys in age groups 3.5–5 and 6.5–8 years.Conclusions: Parallel to earlier reports on different ethnic groups, the results of this study indicate that the permanent teeth of Tanzanian children erupt earlier in girls than in boys, and the mandibular teeth erupt earlier than the corresponding maxillary teeth. The difference between boys and girls was found in both the first and second transitional period. Permanent teeth in Tanzanian children clearly emerge earlier than in Caucasian children.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0528.2002.00020.x
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  • 7
    Electronic Resource
    Electronic Resource
    A meta-analysis of the prevalence of dental agenesis of permanent teeth (2004)
    Oxford, UK : Munksgaard International Publishers
    Community dentistry and oral epidemiology 32 (2004), S. 0 
    Details
    ISSN: 1600-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract –  Objective: To gain more insight into the prevalence of dental agenesis. Methods: Data from Caucasian populations in North America, Australia and Europe were included in a meta-analysis. For the prevalence of African American, Chinese and Arab groups only indications could be reported because of a limited number of studies. Results: Agenesis differs by continent and gender: the prevalence for both sexes was higher in Europe (males 4.6%; females 6.3%) and Australia (males 5.5%; females 7.6%) than for North American Caucasians (males 3.2%; females 4.6%). In addition, the prevalence of dental agenesis in females was 1.37 times higher than in males. The mandibular second premolar was the most affected tooth, followed by the maxillary lateral incisor and the maxillary second premolar. The occurrence of dental agenesis was divided into three main groups: common (P2i 〉 I2s 〉 P2s), less common (I1i 〉 I2i & P1s 〉 Cs & M2i) and rare (M2s & M1s 〉 Ci 〉 M1i & I1s). Unilateral occurrence of dental agenesis is more common than bilateral occurrence. However, bilateral agenesis of maxillary lateral incisors is more common than unilateral agenesis. The overall prevalence of agenesis in the maxilla is comparable with that in the mandible, but a marked difference was found between both jaws regarding tooth type. Absence of one or two permanent teeth is found in 83% of the subjects with dental agenesis. A practical application of the results of the meta-analysis is the estimation of dental treatment need.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0528.2004.00158.x
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  • 8
    Electronic Resource
    Electronic Resource
    Free energy of the Lennard-Jones solid (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 8142-8148 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have determined a simple expression for the absolute Helmholtz free energy of the fcc Lennard-Jones solid from molecular dynamics simulations. The pressure and energy data from these simulations have been fitted to a simple functional form (18 parameters) for densities ranging from around 0.94–1.20, and temperatures ranging from 0.1 to 2.0 (values in reduced Lennard-Jones units). The absolute free energy at an arbitrary state point in this range is obtained by integrating over density and temperature from the triple-point. Our result for the free energy is in very good agreement with the values reported in literature previously. Also the melting line obtained from our free energy expression, in combination with an equation of state for the liquid phase, is in excellent agreement with results by Agrawal and Kofke [Mol. Phys. 85, 43 (1995)] obtained via the Gibbs–Duhem integration method. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1314342
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  • 9
    Electronic Resource
    Electronic Resource
    Chromosomal location of genes for carotenoid pigments in Hordeum chilense (2004)
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 123 (2004), S. 0 
    Details
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In wheat, carotenoids are very important for end-use quality in noodle production. Hexaploid tritordeums are the amphiploids derived from the cross between a wild diploid barley (Hordeum chilense) and durum wheat. Hexaploid tritordeums exhibit a higher carotenoid content than their respective wheat parents. The cross between H1 and H7 lines of H. chilense was used in order to map quantitative trait loci (QTL) for carotenoid content. Multiple interval mapping identified one QTL mapped on chromosome 2. This knowledge is helpful to transfer this favourable trait to other cereal genomes because of the high crossability of H. chilense with other members of the tribe Triticeae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0523.2004.00918.x
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  • 10
    Electronic Resource
    Electronic Resource
    Doubled haploid lines of Brassica carinata with modified erucic acid content through mutagenesis by EMS treatment of isolated microspores (2001)
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 120 (2001), S. 0 
    Details
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Brassica carinata is a potential oilseed crop for the Mediterranean area. Chemical mutagenesis has been applied to microspores of B. carinata with the purpose of identifying lines with altered erucic acid content. From a population of nearly 400 doubled haploid plants recovered, nine lines have been identified that exhibit promising useful changes in erucic acid concentration in the seed oil. Three lines showed erucic acid contents below 25%, with a minimum of 17.1%, and in six lines the level of this fatty acid was greater than 52%. Changes in other fatty acids are also described and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0523.2001.00602.x
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