Chung-Ang University

About: Chung-Ang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 13381 authors who have published 26978 publications receiving 416735 citations. The organization is also known as: CAU & Chung.

Substantiation and recidivism.

Abstract: This article reports rates of recidivism among initially substantiated and initially unsubstantiated child maltreatment events to determine if substantiation status is associated with higher risk of recidivism. This is an important question given recent concerns that unsubstantiated cases may have as high or almost as high a risk of recidivism as do substantiated cases. The data are analyzed at both the victim level and the case level, divided by type of maltreatment, and followed for 4.5 years. The data used are administrative and combine a series of state databases with census data. Analyses are performed at the bivariate and multivariate (Cox proportional hazards model) levels. The main finding is that unsubstantiated cases are at high risk for recidivism, in many cases as high a risk as substantiated cases. Implications for practice, policy, and research are presented with a focus on the importance of providing preventative services to unsubstantiated cases.

Analysis of cache-related preemption delay in fixed-priority preemptive scheduling

Abstract: We propose a technique for analyzing cache-related preemption delays of tasks that cause unpredictable variation in task execution time in the context of fixed-priority preemptive scheduling. The proposed technique consists of two steps. The first step performs a per-task analysis to estimate cache-related preemption cost for each execution point in a given task. The second step computes the worst case response time of each task that includes the cache-related preemption delay using a response time equation and a linear programming technique. This step takes as its input the preemption cost information of tasks obtained in the first step. This paper also compares the proposed approach with previous approaches. The results show that the proposed approach gives a prediction of the worst case cache-related preemption delay that is up to 60 percent tighter than those obtained from the previous approaches.

Engineering and Functionalization of Gelatin Biomaterials: From Cell Culture to Medical Applications.

Abstract: Health care and medicine were revolutionized in recent years by the development of biomaterials, such as stents, implants, personalized drug delivery systems, engineered grafts, cell sheets, and other transplantable materials. These materials not only support the growth of cells before transplantation but also serve as replacements for damaged tissues in vivo. Among the various biomaterials available, those made from natural biological sources such as extracellular proteins (collagen, fibronectin, laminin) have shown significant benefits, and thus are widely used. However, routine biomaterial-based research requires copious quantities of proteins and the use of pure and intact extracellular proteins could be highly cost ineffective. Gelatin is a molecular derivative of collagen obtained through the irreversible denaturation of collagen proteins. Gelatin shares a very close molecular structure and function with collagen and thus is often used in cell and tissue culture to replace collagen for biomaterial purposes. Recent technological advancements such as additive manufacturing, rapid prototyping, and three-dimensional printing, in general, have resulted in great strides toward the generation of functional gelatin-based materials for medical purposes. In this review, the structural and molecular similarities of gelatin to other extracellular matrix proteins are compared and analyzed. Current strategies for gelatin crosslinking and production are described and recent applications of gelatin-based biomaterials in cell culture and tissue regeneration are discussed. Finally, recent improvements in gelatin-based biomaterials for medical applications and future directions are elaborated. Impact statement In this study, we described gelatin's biochemical properties and compared its advantages and drawbacks over other extracellular matrix proteins and polymers used for biomaterial application. We also described how gelatin can be used with other polymers in creating gelatin composite materials that have enhanced mechanical properties, increased biocompatibility, and boosted bioactivity, maximizing its benefits for biomedical purposes. The article is relevant, as it discussed not only the chemistry of gelatin, but also listed the current techniques in gelatin/biomaterial manufacturing and described the most recent trends in gelatin-based biomaterials for biomedical applications.

Crystal Structure of a Junction Between B-DNA and Z-DNA Reveals Two Extruded Bases

Abstract: The existence of left-handed DNA (or Z-DNA) was reported in 1979, and marked by a Nature cover. This week's cover story is the determination of the crystal structure of the junction between left-handed DNA and ‘normal’, right-handed DNA or B-DNA. Each time a DNA segment turns to Z-DNA, two of these B–Z junctions are created. Z-DNA often forms transiently during transcription and other physiological processes, then relaxes to the less energetic B form. The three-dimensional structure shows that the junction is very tight, and that a base pair is pushed out of the double helix, one base on each side of the junction. This adjustment maintains the base stacking that is a major stabilizing factor. These displaced bases may be sites for DNA modification. On the cover, a molecule containing a B–Z junction is shown in the centre, with Z-DNA, naturally, to the left and B-DNA to the right. Left-handed Z-DNA is a higher-energy form of the double helix, stabilized by negative supercoiling generated by transcription or unwrapping nucleosomes1. Regions near the transcription start site frequently contain sequence motifs favourable for forming Z-DNA2, and formation of Z-DNA near the promoter region stimulates transcription3,4. Z-DNA is also stabilized by specific protein binding; several proteins have been identified with low nanomolar binding constants5,6,7,8,9. Z-DNA occurs in a dynamic state, forming as a result of physiological processes then relaxing to the right-handed B-DNA1. Each time a DNA segment turns into Z-DNA, two B–Z junctions form. These have been examined extensively10,11,12, but their structure was unknown. Here we describe the structure of a B–Z junction as revealed by X-ray crystallography at 2.6 A resolution. A 15-base-pair segment of DNA is stabilized at one end in the Z conformation by Z-DNA binding proteins, while the other end remains B-DNA. Continuous stacking of bases between B-DNA and Z-DNA segments is found, with the breaking of one base pair at the junction and extrusion of the bases on each side (Fig. 1). These extruded bases may be sites for DNA modification.