Prevalence of hepatitis B and C viruses in healthy Indonesian blood donors

Blood samples were collected from 7572 healthy volunteer blood donors from 21 of the 27 Indonesian provinces, and tested for antibodies to hepatitis C virus (anti-HCV) using the new second-generation enzyme immunosorbent assay, and also tested for hepatitis B surface antigen (HBsAg). We detected anti-HCV in 2.1% of the blood donors. No statistically significant difference was found between males and females or between locations, but there was a statistically significant increasing likelihood of anti-HCV prevalence with increasing age. HBsAg was found in 8.8% of the 3839 tested donors. There was no statistically significant difference between sexes or age groups, but there was a statistically significant higher prevalence in the islands of Sulawesi and eastern Indonesia. Only 7 individuals, from 5 locations, were both anti-HCV and HBsAg positive. Based on responses to a questionnaire, a history of surgery, blood transfusion, intravenous medication, and acupuncture were identified as risk factors for the presence of anti-HCV. No such risk factor was identified for HBsAg prevalence. The combined data suggest separate modes of transmission for the 2 viruses, and indicate the need for continued surveillance for these agents in Indonesian blood banks.     

The impact of personal innovativeness on product aesthetics and self-connection with brand: a case study of mobile phone users

The concept of personal innovativeness in information technology (PIIT) is often used in an IS context to understand the adoption of IT products and services. However, to the best of our knowledge, few studies have investigated the influence of PIIT on visual product aesthetics (AES) and the consumer's self-connection with brand. By comparing smartphone and functional phone users, this study revealed that PIIT is a significant predictor in explaining centrality of visual product aesthetics (CVPA) and self-brand connection (SBC). PIIT also acts as a predictor of AES and moderates the relationship between satisfaction (SAT) and SBC for smartphone users but not for functional phone users. For both user groups, CVPA predicts AES, and AES contributes to SAT and SBC. The academic and managerial implications of these results were discussed.     

Preparation and performance characteristics of short‐glass‐fiber/maleated styrene–ethylene–butylene–styrene/polypropylene hybrid composites

Eighty/twenty polypropylene (PP)/styrene–ethylene–butylene–styrene (SEBS) and 80/20 PP/maleated styrene–ethylene–butylene–styrene (SEBS‐g‐MA) blends reinforced with 30 wt % short glass fibers (SGFs) were prepared by extrusion and subsequent injection molding. The influence of the maleic anhydride (MA) functional group grafted to SEBS on the properties of SGF/SEBS/PP hybrid composites was studied. Tensile and impact tests showed that the SEBS‐g‐MA copolymer improved the yield strength and impact toughness of the hybrid composites. Extensive plastic deformation occurred at the matrix interface layer next to the fibers of the SGF/SEBS‐g‐MA/PP composites during impact testing. This was attributed to the MA functional group, which enhanced the adhesion between SEBS and SGF. Differential scanning calorimetry measurements indicated that SEBS promoted the crystallization of PP spherulites by acting as active nucleation sites. However, the MA functional group grafted to SEBS retarded the crystallization of PP. Finally, polarized optical microscopy observations confirmed the absence of transcrystallinity at the glass‐fiber surfaces of both SGF/SEBS/PP and SGF/SEBS‐g‐MA/PP hybrid composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1303–1311, 2002     

Using RSS to support mobile learning based on media richness theory

With the rapid development of mobile technologies, mobile learning has become a new trend in education. A better understanding of how to effectively use communication technologies to improve mobile learning is important. The purpose of this paper is to evaluate the media richness of various message delivery methods in the proposed m-learning environment based on media richness theory. Regarding the implications of the media richness theory, this study has identified four factors to evaluate a content in respect to the media richness among SMS, Email, and RSS: timeliness, richness, accuracy and adaptability. By the repeated-measures one-way ANOVA analysis, the results show that: (1) SMS has better performance than Email and RSS on content timeliness; thus SMS may be appropriate for immediate information delivery such as notifying or reminding of some time-sensitive matters; (2) Email has better performance than SMS and RSS on content richness and so may be applied in exhaustive information delivery; (3) RSS has better performance than SMS and Email on content accuracy and adaptability; thus RSS is more appropriate for supporting various front-end mobile devices to access and present the content in a mobile learning environment. According to the results, this study suggests developer and designer of an m-learning environment could adopt suitable information delivery medium to support the corresponding learning activities in a mobile learning environment; moreover, current general e-learning systems, particularly those intending to provide a mobile learning environment, can take advantage of RSS techniques to support mobile access and achieve the goal of mobile learning anytime and anywhere.     

基于RG B-D数据的自适应局部时空特征提取方法

对于一次学习手势识别,噪声和全局经验运动约束严重影响时空特征的精确与充分提取,为此提出了一种融合颜色和深度( RGB-D)信息的自适应局部时空特征提取方法。首先建立连续两灰度帧和两深度帧的金字塔以及相应的光流金字塔作为尺度空间。然后根据灰度和深度光流的水平与垂直方差自适应提取运动感兴趣区域( motion regions of interest, MRoIs)。接着仅在MRoIs内检测角点作为兴趣点,当兴趣点的灰度和深度光流同时满足局部运动约束时即为关键点,局部运动约束是在每个MRoI内自适应确定的。最后在改进的梯度运动空间计算SIFT-like描述子。 Chalearn数据库上的实验结果表明：提出方法得到了较高的识别准确率,其识别性能优于现已发表的方法。     

A 5.4 mW/0.07 mm$^{2}$ 2.4 GHz Front-End Receiver in 90 nm CMOS for IEEE 802.15.4 WPAN Standard

An integrated 2.4 GHz CMOS receiver front-end according to the IEEE 802.15.4 standard is presented in this paper. It integrates the overall RF part, from the balun up to the first stage of the channel filter, as well as the cells for the LO signal conditioning. The proposed architecture is based on a 6 MHz low-IF topology, which uses an inductorless LNA and a new clocking scheme for driving a passive mixer. When integrated in a 90 nm CMOS technology, the receiver front-end exhibits an area of only 0.07 mm², or 0.23 mm² when including an input integrated balun. The overall chip consumes 4 mA from a single 1.35 V supply voltage and it achieves a 35 dB conversion gain from input power in dBm to output voltage in dBvpk, a 7.5 dB NF value, -10 dBm of IIP3 and more than 32 dB of image rejection.     

Cholesteatoma in children

Cholesteatoma in children falls into two main categories: congenital and acquired. Though they present in different ways, both are potentially destructive lesions that are managed surgically. The goals of treatment are to eradicate keratinizing squamous epithelium from the temporal bone and to preserve or restore hearing. These children need to be followed closely by the pediatric otolaryngologist to prevent and control recurrent disease.     

Novel polypropylene biocomposites reinforced with carbon nanotubes and hydroxyapatite nanorods for bone replacements

Multi-walled carbon nanotubes (MWNTs) of 0.1 and 0.3 wt.% and hydoxyapatite nanorods (nHAs) of 8–20 wt.% were incorporated into polypropylene (PP) to form biocomposites using melt-compounding and injection molding techniques. The structural, mechanical, thermal and in vitro cell responses of the PP/MWNT–nHA hybrids were investigated. Tensile and impact tests demonstrated that the MWNT additions are beneficial in enhancing the stiffness, tensile strength and impact toughness of the PP/nHA nanocomposites. According to thermal analysis, the nHA and MWNT fillers were found to be very effective to improve dimensional and thermal stability of PP. The results of osteoblast cell cultivation and dimethyl thiazolyl diphenyl tetrazolium (MTT) tests showed that the PP/MWNT–nHA nanocomposites are biocompatible. Such novel PP/MWNT–nHA hybrids are considered to be potential biomaterials for making orthopedic bone implants.     

Electrical conductivity of polyvinylidene fluoride nanocomposites with carbon nanotubes and nanofibers

Polyvinylidene fluoride nanocomposites with low loading levels of pristine multiwalled carbon nanotubes, carboxyl functionalized multiwalled carbon nanotubes and vapor grown carbon nanofibers were prepared by a versatile coagulation method. The alternating current electrical conductivity of these composites in the frequency range of 40-12 MHz was investigated. The alternating current conductivity of percolating nanocomposites followed a universal dynamic response. Therefore, both the direct current plateau and frequency dependent regime were observed. The percolation threshold of three composite systems was determined to be 1.0, 0.98, and 1.46 vol.%, respectively. Moreover, the percolative nanocomposites exhibited nonlinear current-voltage responses, demonstrating the presence of tunneling conduction.     

Direct current conductivity of carbon nanofiber-based conductive polymer composites: effects of temperature and electric field

Polymer composites based on high density polyethylene (HDPE) and carbon nanofiber (CNF) were fabricated by melt compounding. The dependences of electrical conductivity of HDPE-CNF composites on filler concentration, temperature, and applied electric field were investigated. The results showed that the conductivity of the HDPE-CNF composites follows the scaling law of percolation theory. Increasing temperature caused a sharp increase in the resistivity of HDPE-CNF composites near the melting temperature of HDPE, yielding a positive temperature coefficient (PTC) effect of resistance. The potential mechanisms involved in the PTC effect of such composites were analyzed. An investigation of the effect of electric field on the conductivity of HDPE-CNF composites revealed the presence of tunneling conduction. The tunneling conductivity increased with increasing filler content because of high tunneling frequency, and decreased with rising temperature as a result of gap widening between conducting CNF fillers.