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41.
Although it is well documented that child maltreatment exerts a deleterious impact on child adaptation, much less is known about the precise etiological pathways that eventuate in child abuse and neglect. This paper reports on a multimethod ecological study of the relationship between neighborhood structural factors and child maltreatment reports in African American and European American census tracts. The study had two major components. First, in an aggregate analysis, the effects of four measures of community structure (impoverishment, child care burden, instability, and geographic isolation) on child maltreatment report rates were examined separately for predominantly African American (n = 94) and predominantly European American (n = 189) census tracts. Impoverishment in particular had a significantly weaker effect on maltreatment rates in African American than in European American neighborhoods. Second, focused ethnographies were conducted in four selected census tracts with child maltreatment report rates in the highest and lowest quartiles. Ethnographic data point to the importance of the social fabric in accounting for differences in child maltreatment report rates by predominant neighborhood ethnicity. 相似文献
42.
43.
Endres S Wilke M Knöll P Frank H Kratz M Wilke A 《Journal of materials science. Materials in medicine》2008,19(3):1117-1125
Research has proven that rough surfaces improve both biologic and biomechanical responses to titanium (Ti) implants. The purpose of this study was to evaluate the correlation between the expression of bone cell-associated proteins to Vacuum Plasma-Sprayed Titanium implants (VPS-Ti) with different surface textures in vitro and the bone integration in vivo. The biological performances of the surfaces were evaluated over a period of 8 weeks using human bone marrow cell cultures and Göttinger mini pigs. Cells were cultured on VPS-Ti with two respectively different surface-roughnesses (Ra). The level of Osteoprotegerin (OPG), Osteocalcin (OC) and alkaline phosphatase activity (ALP) were evaluated. The bone integration in vivo was evaluated by histomorphological analyses. A cancellous structured titanium (CS-Ti) construct was used as reference material in both study designs. Comparison of data was conducted using the Scheffé tests and the paired t-test with Bonferroni’s correction. A comparative analysis was done to measure the degree of association between the in vitro and in vivo data. A total amount of OC was significantly increased for VPS-Ti for cells cultured on both VPS-Ti and CS-Ti, while OPG was only detectable after 8 weeks without any significant differences. The ALP activity on all surfaces was not statistically increased. For VPS-Ti with Ra ranging from 0.025 mm up to 0.059 mm, bone integration response was increased, but there was no statistical difference between the VPS-Ti. Expression of OPG, OC and ALP correlated with the histomorphological data over the 8-week period. The in vitro data suggest the superiority of VPS-Ti over CS-Ti, but more importantly, the biocompatibility of testing an in vitro model to predict the outcome and possible integration of implants in vivo. 相似文献
44.
Laura Salo Fanni Mylläri Marek Maasikmets Ville Niemelä Alar Konist Keio Vainumäe 《Aerosol science and technology》2019,53(5):526-539
Particulate matter in the atmosphere is known to affect Earth’s climate and to be harmful to human health. Accurately measuring particles from emission sources is important, as the results are used to inform policies and climate models. This study compares the results of two ELPI?+?devices, two PM10 cascade impactors and an eFilter, in combustion emission measurements. The comparison of the instruments in a realistic setting shows what types of challenges arise from measuring an emission aerosol with unknown particle morphologies and densities, different particle concentrations and high temperature. Our results show that the PM10 cascade impactors have very good intercorrelation when the collected mass is greater than 150?µg, but below that, the uncertainty of the results increases with decreasing mass. The raw signals of two ELPI?+?devices were nearly identical in most samples, as well as the particle number concentrations and size distributions calculated from raw signals; however, transforming the current distributions into mass distributions showed variation in the mass concentration of particles larger than 1?µm. The real-time time signal measured by eFilter was similar to the total current measured by ELPI+. The eFilter and PM10 cascade impactors showed similar particle mass concentrations, whereas ELPI?+?showed clearly higher ones in most cases. We concluded that the difference is at least partially due to volatile components being measured by ELPI+, but not by the mass collection measurements.
Copyright © 2019 American Association for Aerosol Research 相似文献
45.
The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore
to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division
Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the
detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support
high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to
compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide
the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement
campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters,
as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput,
and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly
show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to
radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system.
However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show
that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems. 相似文献
46.
Liisa Voutila Juan Perero Marita Ruusunen Kirsi Jouppila Eero Puolanne 《Journal of the science of food and agriculture》2009,89(15):2527-2534
BACKGROUND: Strips can be easily peeled from raw destructured pork (M. semimembranosus, SM muscle) by hand but in normal meat these strips break. In general, destructured meat is pale in color. Porcine SM muscles have thick muscle fibers which could predispose them to destructuration. This study investigated whether the onset and peak temperatures of thermal shrinkage (To and Tp) of intramuscular connective tissue from SM muscles were associated with muscle fiber thickness, capillary density or extracellular space. We also investigated whether these muscle fiber properties of destructured muscles differed from those of normal muscles. RESULTS: The destructured and normal muscles were similar in muscle fiber cross‐sectional area, capillary density, extracellular space and sarcomere length. To correlated negatively with sarcomere length. The water content of differential scanning calorimetry samples consisting of intramuscular connective tissue was higher in destructured muscles than in normal muscles. CONCLUSION: Muscle fiber properties (muscle fiber cross‐sectional area and sarcomere length) and capillary density are similar in destructured and normal SM muscles. To and Tp of intramuscular connective tissue are similar in destructured and normal muscles. Muscle fiber properties show no association with the thermal shrinkage properties of intramuscular connective tissue. Copyright © 2009 Society of Chemical Industry 相似文献
47.
Ruusunen M Vainionpää J Puolanne E Lyly M Lähteenmäki L Niemistö M Ahvenainen R 《Meat science》2003,64(4):371-381
Quality characteristics of low-salt bologna-type sausage manufactured with sodium citrate (NAC), carboxymethyl cellulose (CMC) and carrageenan (CAR) were examined. Three levels of salt, NAC, CMC and CAR, and two levels of fat were used. Batter and sausage pH values were measured and the frying loss of sausages was analysed by frying slices in an electric grill. Firmness, juiciness, saltiness and flavour intensity of the sausages were sensorically evaluated. Altogether 20 separate sausage batches were prepared. In low-salt sausages containing less than 1.4% NaCl, the use of NAC, CAR and CMC decreased frying loss and increased saltiness. NAC and CAR also increased flavour intensity, but CMC did not. Furthermore, NAC, CAR and CMC increased the firmness of the low-salt sausage, while only NAC increased juiciness when the NaCl content was below 1.4%. NAC increases, however, the sodium content of the product. Therefore, it can be concluded that in low-salt sausages no additive alone is suitable. A mixture of NAC and CAR appears to be the best combination. 相似文献
48.
Jessica L. Stoner Philip A. E. Murgatroyd Marita O'Sullivan Matthew S. Dyer Troy D. Manning John B. Claridge Matthew J. Rosseinsky Jonathan Alaria 《Advanced functional materials》2019,29(11)
Correlated metallic transition metal oxides offer a route to thin film transparent conductors that is distinct from the degenerate doping of broadband wide gap semiconductors. In a correlated metal transparent conductor, interelectron repulsion shifts the plasma frequency out of the visible region to enhance optical transmission, while the high carrier density of a metal retains sufficient conductivity. By exploiting control of the filling, position, and width of the bands derived from the B site transition metal in ABO3 perovskite oxide films, it is shown that pulsed laser deposition‐grown films of cubic SrMoO3 and orthorhombic CaMoO3 based on the second transition series cation 4d2 Mo4+ have superior transparent conductor properties to those of the first transition series 3d1 V4+‐based SrVO3. The increased carrier concentration offered by the greater bandfilling in the molybdates gives higher conductivity while retaining sufficient correlation to keep the plasma edge below the visible region. The reduced binding energy of the n=4 frontier orbitals in the second transition series materials shifts the energies of oxide 2p to metal nd transitions into the near‐ultraviolet to enhance visible transparency. The A site size‐driven rotation of MoO6 octahedra in CaMoO3 optimizes the balance between plasma frequency and conductivity for transparent conductor performance. 相似文献
49.
Maoshuai He Alexander I. Chernov Elena D. Obraztsova Jani Sainio Emma Rikkinen Hua Jiang Zhen Zhu Antti Kaskela Albert G. Nasibulin Esko I. Kauppinen Marita Niemelä Outi Krause 《Nano Research》2011,4(4):334-342
Single-walled carbon nanotubes (SWNTs) have been grown on a silica-supported monometallic nickel (Ni) catalyst at temperatures ranging from as low as 450 °C to 800 °C. Different spectroscopic techniques, such as Raman, photoluminescence emission (PLE), and ultra violet-visible-near infrared (UV-vis-NIR) absorption spectroscopy were used to evaluate the diameter and quality of the SWNTs grown over the Ni catalyst at different temperatures. The analysis revealed that high quality SWNTs with a very narrow diameter distribution were obtained at a growth temperature of 500 °C. In the PLE and absorption spectra, differences were observed between the SWNTs grown on Ni and those grown on cobalt (Co). This result expands the potential of growing a specific (n, m) tube species with relatively high abundance by tuning the catalyst composition. Furthermore, the prerequisites for the low temperature growth of SWNTs over a monometallic transition metal catalyst have been elucidated. 相似文献
50.
Endotoxins associated with cyanobacteria and their removal during drinking water treatment 总被引:7,自引:0,他引:7
The aim of this study was to investigate endotoxin concentrations in cyanobacterial water blooms and strains, and to assess the removal of endotoxins during drinking water treatment. Endotoxin concentrations were measured from 151 hepatotoxic, neurotoxic and non-toxic cyanobacterial water blooms by using Limulus amebocyte lysate (LAL) assay, and the results were compared to bacterial data. Endotoxin activities ranged from 20 to 3.8 x 10(4) endotoxin units (EU) per ml. Endotoxicity of the samples correlated with phycobiliprotein concentration that was used to assess cyanobacterial abundance, heterotrophic plate count, and Aeromonas spp. but it did not correlate with the number of coliforms or streptococci. The high endotoxin concentrations occasionally detected in the water bloom samples were probably due to Gram negative bacteria that existed together with cyanobacteria since the 26 axenic cyanobacterial strains from different genera that were studied showed very low endotoxin activity. No differences in endotoxin activity were detected between hepatotoxic, neurotoxic and non-toxic strains. Removal of endotoxins during drinking water treatment was studied at nine waterworks that previously had been associated with high numbers of cyanobacteria and that used different processes for water purification. Endotoxin concentration in raw waters ranged from 18 to 356 EU ml(-1). The treatment processes reduced 59-97% of the endotoxin activity; in the treated water the concentration ranged from 3 to 15 EU ml(-1). The most significant reduction occurred at the early stages of water treatment, during coagulation, settling and sand filtration. Activated carbon filtration either increased or had no effect on endotoxin concentration. Ozonation and chlorination had little effect on the endotoxin concentrations. 相似文献