Granulometric Characterization and Study of Ibuprofen Lysinate by Means of an Image Processor

This article examines the possibility of using the microscope methods in conjunction with an image processor (Kontron IBAS 2000) to granulometrically characterise ibuprofen lysinate, a recently discovered soluble salt of ibuprofen (analgesic, anti-inflammatory and antipyretic). Likewise, the advantages this method has over conventional microscope methods and other existing procedures are analysed. The methodology applied is described and the findings reported. The crystal morphology of ibuprofen lysinate is acicular. All parameters determined follow a log-normal distribution pattern and not a Gauss distribution pattern. The Feret diameter distribution did not follow either of these patterns. As a result, the Feret diameters are the least representative parameters of this active agent's granulometry. On the other hand, the equivalent diameter is the most representative parameter. From a technological and pharmaceutical point of view, the drugs' appearance is that of a granulometrically homogenous powder. Finally, the article demonstrates that apart from being much easier and much more reliable, the method applied saves a considerable amount of time when compared with the conventional microscope method.     

Evaluation of structure and morphology of aluminum powder particles milled at different conditions

Micron sized aluminum powder was milled together with different process control agents (PCAs) including ethanol, graphite and stearic acid for various periods of time. The morphology of powder particles was characterized quantitatively using an image processing program and optical microscopy (OM). Work hardening effect on final particles morphology was evaluated by a number of structural characteristics such as dislocation density and crystallite size calculated by the modified Warren–Averbach method. Normal distribution curves for three morphological parameters of Feret diameter, aspect ratio and roughness, were obtained. The results showed that the type of PCA used during the milling operation was much more effective parameter on morphology, dislocation density and crystallite size of powder particles in comparison with the milling time. The specimens with higher work hardening characteristics showed smaller Feret diameter and aspect ratio. Also, ethanol as a liquid PCA found to be more effective comparing with other solid PCAs.     

Feret coefficients for white self-compacting concrete

Several tests on white mortar, micro-concrete, concrete and self-compacting concrete, considering different additions and admixtures, were conducted to characterize white cement and determine the corresponding Feret coefficients. It was concluded that: (1) it is possible to make different mixtures of white self-compacting concrete (WSCC) with the materials adopted; (2) the method suggested by the JSCE is the one that better adapts to the studied WSCC mixtures; (3) the obtained values for the Feret coefficients can help the concrete designer predicting the compressive strength of the WSCC; (4) the Feret coefficients for WSCC are different from those for regular, white or gray, concrete.1359-5997 © 2005 RILEM. All rights reserved.     

图像法集料粒径检测表征参数的选择及实验研究

图像法检测集料粒径时,集料的表征参数是影响粒径检测结果的重要因素。研发的图像法集料粒径检测系统由LED光源、工业CCD相机和LabVIEW软件平台组成。采用不同的等效径对图像中的集料粒径分级,通过不同等效体积对图像中的集料质量进行计算,并对比不同等效径和等效体积算法对集料粒径检测结果产生的影响。为了使图像法的检测结果和筛分法结果相近,方便在线人员观测,得到了一组符合筛分法检测的图像法粒径表征参数。实验结果表明:选择等效椭圆Feret短径作为等效粒径最符合筛分法的粒径含量,选择投影面积×等效椭圆Feret短径作为等效体积和实际体积相关性最大。     

Characterization of microshrinkage casting defects of Al–Si alloys by X-ray computed tomography and metallography

The statistical pore size characterization by metallography in the framework of Extreme Value Statistics (EVS) is presented and applied to different sets of cast AlSi7Mg specimens. Specimen production by separate casting or by extraction from automotive cast parts is found to result in different SDAS and porosity (i.e. pore morphology and size) but did not influence the fatigue strength. The application of two equivalent pore size definitions (i.e. maximum Feret diameter and (Area)^1/2) combined with the EVS approach is discussed in terms of predicted critical pore sizes and observed fatigue strengths. The role of casting pore morphology on stress concentration is investigated using the X-ray computed tomography and the finite element method.     

A preliminary study of sexual activity as a distraction for young drivers

In what may be the first in-depth study of sexual activity as a driving distraction in the US, a sample of 195 male and 511 female college students at a Midwestern university (M age = 19.7) participated in an on-line study of sex while driving (SWD). Of these, 64 (32.8%) men and 47 (9.3%) women had engaged in sex while driving (SWD). Nine percent of men and 29% of women had engaged in SWD as a passenger. In most recent SWD incidents, respondents reported that the two most common acts were oral sex (70.3%) and genital touching (60.4%). About 11% engaged in vaginal intercourse. Sexual activity lasted from 1 to 10 min for 42.7% of the respondents. Nearly half (49.1%) were traveling 61–80 mph during sex. Considering respondents’ lifetime incidents of SWD, the most common driving errors reported were speeding (37.8%), drifting into another lane (36%), and letting go of the steering wheel (10.8%). Only 1.8% nearly had a crash, and none actually had a crash. Separate regression analyses for male and female respondents revealed that lower intentions to engage in SWD in the future were associated with higher estimates of the probability of a car crash. The authors consider SWD to be an under-reported in-vehicle distraction and encourage more research and prevention efforts.     

反应器长径比对化学气相沉积SiC沉积动力学的影响

以三氯甲基硅烷(MTS)和H₂为前驱体,在沉积温度900~1 050℃,H₂和MTS摩尔比为4~20和滞留时间0.4~1 s下,采用化学气相沉积(CVD)工艺研究沉积反应器长径比分别为7∶6和7∶2时的碳化硅(SiC)沉积动力学。结果发现,不同尺寸反应器中SiC沉积速率随工艺参数变化的规律性差异明显。长径比7∶6的反应器中SiC平均沉积速率随着温度的增加而增加,而长径比7∶2的反应器中SiC平均沉积速率随着温度先增加后降低,且长径比7∶6的沉积反应器中沿程SiC沉积存在多重稳态的特征。不同H₂/MTS摩尔比下SiC沉积速率变化规律在两种反应器中基本一致,尽管长径比7∶6的反应器中出现了SiC沿程的多重择优沉积位置,但整体来说H₂对SiC沉积的抑制作用远大于反应器尺寸效应所带来的影响。长径比7∶6反应器中SiC平均沉积速率随滞留时间的增加而降低,但沿程沉积速率受反应器尺寸效应并没有出现单调降低的规律;长径比7∶2反应器中SiC平均沉积速率和沿程沉积速率均随滞留时间增加而降低后趋于稳定。利用COMSOL软件对两种长径比反应器的流场和温度场进行了数值模拟分析发现,长径比7∶6的反应器产生明显的径向流速差,而且轴向和径向流速差和温差较大,而长径比7∶2的沉积反应器流场和温度场较为均匀,这种反应器尺寸效应引起的实际工艺参数和理论工艺参数之间的偏差,正是实验中不同长径比反应器中SiC沉积动力学规律差异的原因。      

Long-Tern Skin Permeation Kinetics of Estradiol: (II) Kinetics of Skin Uptake, Binding, and Metabolism

The in vitro skin permeation system developed in this laboratory was utilized to investigate the kinetics of uptake, binding, and metabolism of estradiol, the female hormone, by the hairless mouse skin. The kinetics of uptake of estradiol and its subsequent metabolism to estrone by the skin were examined by exposing one side of a freshly excised skin to an estradiol solution, while the other side of the skin was protected with an impermeable aluminum foil.

The results concluded that the stratum corneum plays a rate-limiting role in the uptake and binding of estradiol and its metabolism to estrone by the skin. The mechanisms of the uptake and binding of estradiol to whole skin tissue (with stratum corneum) showed a sex dependence, with the rate higher in the female than in the male mouse. On the other hand, no sex-dependent difference was observed in the mechanism and rate of metabolism to estrone.

After stripping off the rate-limiting stratum corneum, the mechanisms of the uptake, binding and metabolism of estradiol all became sex dependent with identical rates observed between male and female mice in the initial 14 hrs of the experiment; Between 14 to 21 hrs, the rates increased substantially with the female skin, but not with the male skin. The increase in the rate of uptake of estradiol by the female skin was related primarily to the increased rate of metabolism of estradiol to estrone.     

Helmet effectiveness in preventing motorcycle driver and passenger fatalities

Helmet effectiveness in preventing fatalities to motorcycle drivers and passengers was determined by applying the double pair comparison method to the Fatal Accident Reporting System (PARS) data for 1975 through 1986. Motorcycles with a driver and a passenger, at least one of whom was killed, were used. In order to reduce as much as possible potentially confounding effects due to the dependence of survivability on sex and age, the analysis is confined to male drivers (there were insufficient female driver data), and to cases in which the driver and passenger age do not differ by more than three years. Motorcycle helmet effectiveness estimates are found to be relatively unaffected by performing the analyses in a number of ways different from that indicated above. It was found that helmets are (28 ± 8)% effective in preventing fatalities to motorcycle riders (the error is one standard error), the effectiveness being similar for male and female passengers, and similar for drivers and passengers. An additional result found was that the fatality risk in the driver seat exceeds that in the passenger seat by (26 ± 2)%. The 28% effectiveness found generates calculated fatality increases from repeal of mandatory helmetwearing laws that are compatible with observed increases.     

Use of crospovidone as pelletization aid as alternative to microcrystalline cellulose: effects on pellet properties

Background: Microcrystalline cellulose (MCC) is the most important pelletization aid in extrusion/spheronization. Because of known disadvantages, the search for substitutes is ongoing. In this context, crospovidone has proven to offer substantial advantages as pelletization aid because of its ability to turn low-soluble active ingredients into fast-dissolving stable pellets. Method: Pellets from crospovidone with different amounts of paracetamol, hydrochlorothiazide, and spironolactone as model drugs were prepared by extrusion/spheronization. For comparison, pellets with MCC as extrusion aid were also produced. The pellets of different formulations were evaluated in terms of yield, aspect ratio, mean Feret diameter, 10% interval fraction, tensile strength, disintegration, and drug release profile. Results: Only crospovidone types exhibiting small particle sizes are suitable as pelletization aid. While maintaining the pharmaceutical quality aspects, it was possible to incorporate up to 60% (w/w) active pharmaceutical ingredients (API) into pellets with crospovidone. The most distinguished differences between pellets based on crospovidone and MCC are the disintegration and drug release behavior. The pellets containing binary mixtures of the low-soluble APIs and crospovidone resulted in fast release in contrast to the pellets with MCC as pelletization aid, which exhibited a slow release. Conclusion: Crospovidone shows an excellent behavior as pelletization aid and produces fast-releasing pellets even with low-soluble APIs.     

The analysis of change in occupational qualities by ageing

The ageing process was studied by means of the changes in the aptitude measured by the general vocational aptitude test constructed by the Japan Labour Ministry. The aptitudes were classified in terms of three activities, viz. analytical, synthetic and motion. Four groups of subjects participated in the study: 271 male manual workers aged 20-59; 111 male non-manual workers aged 20-59; 196 male and female university students aged 18-19; and 123 male and female junior high school students aged 13-15. Changes with age were observed in the scores, in the activity balance diagram and in the time required for the basic motion (therblig).     

Synergism between 2,3,7,8-tetrachlorodibenzo-p-dioxin and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone on lung tumor incidence in mice

Although 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is classified as a human carcinogen, TCDD only induced oxidative DNA damages. In our present study, we combined TCDD with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) to investigate their tumorigenic effects on lung tumor formation in A/J mice. Application of NNK at a tumorigenic dose (2 mg/mouse) induced lung adenoma in both male and female A/J mice. Neither application of NNK at a non-tumorigenic dose (1 mg/mouse) nor repeated application of TCDD alone increased tumor incidence. Following the single injection of NNK at a non-tumorigenic dose (1 mg/mouse), repeated application of TCDD significantly increased the lung tumor incidence in female, but not in male, A/J mice 24 weeks later. Utilizing the real-time RT-PCR array, we found that P16 mRNA was significantly reduced in female lung, but not male lung, of NNK/TCDD co-treated A/J mice. With immunohistochemical staining, we confirmed that nuclear P16 protein was reduced in the lungs of NNK/TCDD co-treated female mice. These data suggest that P16 reduction at least partially contributed to synergistic effects of TCDD in lung tumorigenesis.     

Citation analysis of foreign sources in Japanese geographical serials

A comparison of sources cited in the Japanese language Geographical Review of Japan and six western language, Japanese geographical serials reveals that while both cite the same proportion of foreign sources (a third), authors tend to select Japanese sources which are written in the language of the host publication. Foreign sources in the Japanese literature are overwhelmingly from the English language world, especially the United States, with a small admixture in German, from the F.R. Germany. The proportion of foreign sources in the Japanese literature appears to be in decline.     

Cryogenic optical performance of the ASTRO-F SiC telescope

The lightweight cryogenic telescope on board the Japanese infrared astronomical satellite, ASTRO-F, which is scheduled to be launched early in 2006, forms an F/6 Ritchey-Chretien system with a primary mirror of 710 mm in diameter. The mirrors of the ASTRO-F telescope are made of sandwich-type silicon carbide (SiC) material, comprising a porous core and a chemical-vapor-deposited coat of SiC on the surface. To estimate the optical performance of the flight model telescope, the telescope assembly was tested at cryogenic temperatures, the total wavefront errors of which were measured by an interferometer from outside a liquid-helium chamber. As a result, the wavefront error obtained at 9 K shows that the imaging performance of the ASTRO-F telescope is diffraction limited at a wavelength of 6.2 microm, which is a little worse than our original goal of diffraction-limited performance at 5.0 microm.     

New technology for fabrication of C/SiC composites reinforced by continuous carbon tows

Abstract

Carbon/silicon carbide composites were fabricated using the continuous synchronous composite (CSC) process, which is an improved technology based on conventional chemical vapour infiltration principles to fabricate ceramic matrix composites reinforced with carbon cloth or continuous tows which are not braided to a preform. In the CSC process, a gradient temperature field on the surface of the graphitic substrate, consisting of high (1000–1200°C), intermediate (900–1000°C), and low (700–900°C) temperature regions, was obtained by a bottom heating element. Since the rotation of the substrate accompanied simultaneously the preparation of the reinforcement phase and the deposition of the SiC matrix, micropores were well infiltrated in the intermediate temperature regions by diffusion transport, and macropores were well infiltrated in the high temperature regions with flow transport, respectively. Using methyltrichlorosilane (MTS) as a precursor, with hydrogen as a carrying gas and argon gas as a diluent, in the present studies, densification of C/SiC composites was uniform, and the highest deposition rate obtained was 0.168 mg cm^-2 min^-1), and the conversion efficiency of MTS varied from 31% to a maximum of 47%.     

Using the U.S. National Household Travel Survey to estimate the impact of passenger characteristics on young drivers’ relative risk of fatal crash involvement

Motor vehicle crashes are the main cause of morbidity and mortality in teenagers and young adults in the United States. Driving exposure and passenger presence, which can both vary by driver and passenger characteristics, are known to influence crash risk. Some studies have accounted for driving exposure in calculating young driver fatal crash risk in the presence of passengers, but none have estimated crash risk by driver sex and passenger age and sex. One possible reason for this gap is that data collection on driving exposure often precludes appropriate analyses. The purpose of this study was to examine, per 10 million vehicle trips (VT) and vehicle-miles traveled (VMT), the relative risk of fatal crash involvement in 15-20-year-old male and female drivers as a function of their passenger's age and sex, using solo driving as the referent. The Fatality Analysis Reporting System provided fatal motor vehicle crash data from 1999 to 2003 and the 2001 National Household Travel Survey (NHTS) provided VT and VMT. The NHTS collects driving exposure for both household and non-household members (e.g., friends, colleagues), but demographic characteristics only on household members. Missing age and sex of non-household passengers were imputed with hot deck using information from household passengers’ trips with non-household drivers, thereby enabling the calculation of crash rate and relative risk estimates based upon driver and passenger characteristics. Using this approach, the highest risk was found for young male drivers with 16-20-year-old passengers (relative risk [RR] per 10 million VT = 7.99; 95% confidence interval [CI], 7.34-8.69; RR per 10 million VMT = 9.94; 95% CI, 9.13-10.81). Relative risk was also high for 21-34-year-old passengers, again particularly when both drivers and passengers were male. These effects warrant further investigation and underscore the importance of considering driving exposure by passenger characteristics in understanding crash risk. Additionally, as all imputation techniques are imperfect, a more accurate estimation of U.S. fatal crash risk per distance driven would require national surveys to collect data on non-household passenger characteristics.     

Has the difference in accident patterns between male and female drivers changed between 1984 and 2000?

The motorcar accident pattern of culpable young (18-25 years old) and middle-aged (35-55 years old) male and female drivers was studied in Finland. The aim was to see whether the difference in accident patterns between males and females has remained constant or whether it has changed over a 16-year period. Two different sets of traffic accident data were used. The first set of data covered all motorcar accidents for which damages were paid between 1987 and 2000, a total of 140802 accidents. The second set of data covered all fatal motor vehicle accidents in Finland during the time period between 1984 and 2000, a total of 2401 accidents. The results are analysed and discussed in the framework of a four-level hierarchical model of driving behaviour [Keskinen, E., 1996. Why do young drivers have more accidents? In: Junge, F., Fahrerinnen (Eds.), Young Drivers (in German and in English). Berichte der Bundesanstalt für Strabetaenwesen, Mensch und Sicherheit, Heft M 52, Bergisch Gladbach, Germany; Hatakka, M., Keskinen, E., Gregersen, N.P., Glad, A., Hernetkoski, K., 2002. From control of the vehicle to personal self-control; broadening the perspectives to driver education. Transportation Res. Part F 5 (3), 201-215]. Female drivers had proportionally more accidents that were connected to vehicle manoeuvring and control of traffic situations, e.g. reversing and loss-of-control accidents in a sober state and when not speeding. Male drivers, and especially young male drivers, had proportionally more accidents connected to higher levels of driving behaviour like motives for driving and attitudes. Factors that characterised these accidents were speeding and alcohol consumption. Male drivers also had previous traffic offences more often than female drivers. The study concludes that the difference in accident patterns between male and female drivers has remained constant, i.e. the accident pattern of female drivers was as dissimilar to the accident pattern of male drivers in the year 2000 as in the middle of the 1980s.     

The effect of thread dimensional conformance on yield and tensile strength

This paper presents the results from tests that investigate the effect of thread dimensional conformance of fasteners on yield and tensile strength. Test specimens include combinations of bolts and nuts within dimensional conformance as specified by ASME Standard B1.1-1992, as well as bolts with undersized pitch and major diameters and nuts with oversized pitch and minor diameters. Tensile tests were performed in accordance with ASTM F606-95b. Data from the tests show reduced yield and tensile strength for the fastener combinations with undersized pitch and major bolt diameters or oversized pitch and minor nut diameters, compared to fastener combinations within conformance. Variations in bolt pitch diameter were found to affect the yield and tensile strength by about an order of magnitude more than variations in bolt major diameter or nut pitch and minor diameters. The mean tensile strength for conforming product was found to be as much as 20% greater than the tensile strength for nonconforming product.     

Synthesis of silicon carbide nanotubes by chemical vapor deposition

Silicon carbide nanotubes (SiCNTs) were directly synthesized by chemical vapor deposition (CVD) in the paper. Methyltrichlorosilane (MTS) was selected as the SiC gaseous source and, ferrocence and thiophene as the catalyst and the cocatalyst, respectively. The influences of reaction temperature, contents of catalyst and cocatalyst, and content of gaseous source on the morphologies of the products were investigated, respectively. The products were identified by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX), respectively. The synthesis of SiCNTs by CVD suggested a condition-dependent process. Novel SiCNTs, with 20 approximately 80 nm in outer diameter and 15 approximately 35 nm in inner diameter, respectively, were observed. The wall structure similar to that of carbon nanotubes was not found for the SiCNTs.     

Properties of Nd3+-doped and undoped tetragonal PbWO4, NaY(WO4)2, CaWO4, and undoped monoclinic ZnWO4 and CdWO4 as laser-active and stimulated raman scattering-active crystals

Spectroscopic, laser, and chi((3)) nonlinear optical properties of tetragonal PbWO(4), NaY(WO(4))(2), CaWO(4), and monoclinic CdWO(4) and ZnWO(4) were investigated. Particular attention was paid to Nd(3+)-doped and undoped PbWO(4) and NaY(WO(4))(2) crystals. Their absorption and luminescence intensity characteristics, including the peak cross sections of induced transitions, were determined. Pulsed and continuous-wave lasing in the two 4F(3/2)-->4I(11/2) and 4F(3/2)-->4I(13/2) channels was excited. For these five tungstates, highly efficient (greater than 50%) multiple Stokes generation and anti-Stokes picosecond generation were achieved. All the observed scattered laser components were identified. These results were analyzed and compared with spectroscopic data from spontaneous Raman scattering. A new crystalline Raman laser based on PbWO(4) was developed for the chi((3)) conversion frequency of 1-microm pump radiation to the first Stokes emission with efficiency up to 40%. We classify all the tungstates as promising media for lasers and neodymium-doped crystals for self-stimulated Raman scattering lasers.