In-vivo phase contrast magnetic resonance angiography of the cerebrovascular system: a comparative study with duplex sonography.

PURPOSE Assessment of the cerebral blood flow (CBF) is crucial in the evaluation of patients with steno-occlusive diseases of the arteries supplying the brain for prediction of stroke risk. Quantitative phase contrast magnetic resonance angiography (PC-MRA) can be utilised for noninvasive quantification of CBF. The aim of this study was to validate in-vivo PC-MRA data by comparing them with colour-coded duplex (CCD) sonography in patients with cerebrovascular disease. METHODS AND MATERIALS We examined 24 consecutive patients (mean age 63 years) with stenosis of arteries supplying the brain using PC-MRA and CCD. Velocities were measured in a total of 209 stenotic and healthy arterial segments (110 extra- and 99 intracranial). RESULTS Moderate to good correlation of velocity measurements between both techniques was observed in all six extracranial and five out of seven intracranial segments (p <0.05). Velocities measured with CCD sonography were generally higher than those obtained by PC-MRA. Reversal of flow direction was detected consistently with both methods. CONCLUSION PC-MRA represents a robust, standardised magnetic resonance imaging technique for blood flow measurements within a reasonable acquisition time, potentially evolving as valuable work-up tool for more precise patient stratification for revascularisation therapy. PC-MRA overcomes relevant weaknesses of CCD in being not operator-dependent and not relying on a bone window to assess the intracranial arteries.

Osseointegration of titanium implants functionalised with phosphoserine-tethered poly(epsilon-lysine) dendrons: a comparative study with traditional surface treatments in sheep

The aim of this study was to analyse the osseointegrative potential of phosphoserine-tethered dendrons when applied as surface functionalisation molecules on titanium implants in a sheep model after 2 and 8 weeks of implantation. Uncoated and dendron-coated implants were implanted in six sheep. Sandblasted and etched (SE) or porous additive manufactured (AM) implants with and without additional dendron functionalisation (SE-PSD; AM-PSD) were placed in the pelvic bone. Three implants per group were examined histologically and six implants were tested biomechanically. After 2 and 8 weeks the bone-to-implant contact (BIC) total values of SE implants (43.7 ± 12.2; 53.3 ± 9.0 %) and SE-PSD (46.7 ± 4.5; 61.7 ± 4.9 %) as well as AM implants (20.49 ± 5.1; 43.9 ± 9.7 %) and AM-PSD implants (19.7 ± 3.5; 48.3 ± 15.6 %) showed no statistically significant differences. For SE-PSD and AM-PSD a separate analysis of only the cancellous BIC demonstrated a statistically significant difference after 2 and 8 weeks. Biomechanical findings proved the overall increased stability of the porous implants after 8 weeks. Overall, the great effect of implant macro design on osseointegration was further supported by additional phosphoserine-tethered dendrons for SE and AM implants.

Evaluation of the maxillary sinus in panoramic radiography—a comparative study

Background: The aim of this study was to evaluate the validity and the inter- and intra-examiner reliability of panoramic-radiograph-driven findings of different maxillary sinus anatomic variations and pathologies, which had initially been prediagnosed by cone beam computed tomography (CBCT). Methods: After pairs of two-dimensional (2D) panoramic and three-dimensional (3D) CBCT images of patients having received treatment at the outpatient department had been screened, the predefinition of 54 selected maxillary sinus conditions was initially performed on CBCT images by two blinded consultants individually using a questionnaire that defined ten different clinically relevant findings. Using the identic questionnaire, these consultants performed the evaluation of the panoramic radiographs at a later time point. The results were analyzed for inter-imaging differences in the evaluation of the maxillary sinus between 2D and 3D imaging methods. Additionally, two resident groups (first year and last year of training) performed two diagnostic runs of the panoramic radiographs and results were analyzed for inter- and intra-observer reliability. Results: There is a moderate risk for false diagnosis of findings of the maxillary sinus if only panoramic radiography is used. Based on the ten predefined conditions, solely maxillary bone cysts penetrating into the sinus were frequently detected differently comparing 2D to 3D diagnostics. Additionally, on panoramic radiographs, the inter-observer comparison demonstrated that basal septa were significantly often rated differently and the intra-observer comparison showed a significant lack in reliability in detecting maxillary bone cysts penetrating into the sinus. Conclusions: Panoramic radiography provides the most information on the maxillary sinus, and it may be an adequate imaging method. However, particular findings of the maxillary sinus in panoramic imaging may be based on a rather examiner-dependent assessment. Therefore, a persistent and precise evaluation of specific conditions of the maxillary sinus may only be possible using CBCT because it provides additional information compared to panoramic radiography. This might be relevant for consecutive surgical procedures; consequently, we recommend CBCT if a precise preoperative evaluation is mandatory. However, higher radiation dose and costs of 3D imaging need to be considered. Keywords: Panoramic radiography; Cone beam computed tomography; Maxillary sinus; Inter-imaging method differences; Inter-examiner reliability; Intra-examiner reliability

Variable phenotypic expressivity in inbred retinal degeneration mouse lines: A comparative study of C3H/HeOu and FVB/N rd1 mice

PURPOSE Recent advances in optogenetics and gene therapy have led to promising new treatment strategies for blindness caused by retinal photoreceptor loss. Preclinical studies often rely on the retinal degeneration 1 (rd1 or Pde6b(rd1)) retinitis pigmentosa (RP) mouse model. The rd1 founder mutation is present in more than 100 actively used mouse lines. Since secondary genetic traits are well-known to modify the phenotypic progression of photoreceptor degeneration in animal models and human patients with RP, negligence of the genetic background in the rd1 mouse model is unwarranted. Moreover, the success of various potential therapies, including optogenetic gene therapy and prosthetic implants, depends on the progress of retinal degeneration, which might differ between rd1 mice. To examine the prospect of phenotypic expressivity in the rd1 mouse model, we compared the progress of retinal degeneration in two common rd1 lines, C3H/HeOu and FVB/N. METHODS We followed retinal degeneration over 24 weeks in FVB/N, C3H/HeOu, and congenic Pde6b(+) seeing mouse lines, using a range of experimental techniques including extracellular recordings from retinal ganglion cells, PCR quantification of cone opsin and Pde6b transcripts, in vivo flash electroretinogram (ERG), and behavioral optokinetic reflex (OKR) recordings. RESULTS We demonstrated a substantial difference in the speed of retinal degeneration and accompanying loss of visual function between the two rd1 lines. Photoreceptor degeneration and loss of vision were faster with an earlier onset in the FVB/N mice compared to C3H/HeOu mice, whereas the performance of the Pde6b(+) mice did not differ significantly in any of the tests. By postnatal week 4, the FVB/N mice expressed significantly less cone opsin and Pde6b mRNA and had neither ERG nor OKR responses. At 12 weeks of age, the retinal ganglion cells of the FVB/N mice had lost all light responses. In contrast, 4-week-old C3H/HeOu mice still had ERG and OKR responses, and we still recorded light responses from C3H/HeOu retinal ganglion cells until the age of 24 weeks. These results show that genetic background plays an important role in the rd1 mouse pathology. CONCLUSIONS Analogous to human RP, the mouse genetic background strongly influences the rd1 phenotype. Thus, different rd1 mouse lines may follow different timelines of retinal degeneration, making exact knowledge of genetic background imperative in all studies that use rd1 models.

Comparative Study of Digital Rights Management Systems for Music and Text Files

Digital Rights Management Systems (DRMS) are seen by content providers as the appropriate tool to, on the one hand, fight piracy and, on the other hand, monetize their assets. Although these systems claim to be very powerful and include multiple protection technologies, there is a lack of understanding about how such systems are currently being implemented and used by content providers. The aim of this paper is twofold. First, it provides a theoretical basis through which we present shortly the seven core protection technologies of a DRMS. Second, this paper provides empirical evidence that the seven protection technologies outlined in the first section of this paper are the most commonly used technologies. It further evaluates to what extent these technologies are being used within the music and print industry. It concludes that the three main Technologies are encryption, password, and payment systems. However, there are some industry differences: the number of protection technologies used, the requirements for a DRMS, the required investment, or the perceived success of DRMS in fighting piracy.

Carbohydrate Estimation by a Mobile Phone-Based System Versus Self-Estimations of Individuals With Type 1 Diabetes Mellitus: A Comparative Study

Background: Diabetes mellitus is spreading throughout the world and diabetic individuals have been shown to often assess their food intake inaccurately; therefore, it is a matter of urgency to develop automated diet assessment tools. The recent availability of mobile phones with enhanced capabilities, together with the advances in computer vision, have permitted the development of image analysis apps for the automated assessment of meals. GoCARB is a mobile phone-based system designed to support individuals with type 1 diabetes during daily carbohydrate estimation. In a typical scenario, the user places a reference card next to the dish and acquires two images using a mobile phone. A series of computer vision modules detect the plate and automatically segment and recognize the different food items, while their 3D shape is reconstructed. Finally, the carbohydrate content is calculated by combining the volume of each food item with the nutritional information provided by the USDA Nutrient Database for Standard Reference. Objective: The main objective of this study is to assess the accuracy of the GoCARB prototype when used by individuals with type 1 diabetes and to compare it to their own performance in carbohydrate counting. In addition, the user experience and usability of the system is evaluated by questionnaires. Methods: The study was conducted at the Bern University Hospital, “Inselspital” (Bern, Switzerland) and involved 19 adult volunteers with type 1 diabetes, each participating once. Each study day, a total of six meals of broad diversity were taken from the hospital’s restaurant and presented to the participants. The food items were weighed on a standard balance and the true amount of carbohydrate was calculated from the USDA nutrient database. Participants were asked to count the carbohydrate content of each meal independently and then by using GoCARB. At the end of each session, a questionnaire was completed to assess the user’s experience with GoCARB. Results: The mean absolute error was 27.89 (SD 38.20) grams of carbohydrate for the estimation of participants, whereas the corresponding value for the GoCARB system was 12.28 (SD 9.56) grams of carbohydrate, which was a significantly better performance ( P=.001). In 75.4% (86/114) of the meals, the GoCARB automatic segmentation was successful and 85.1% (291/342) of individual food items were successfully recognized. Most participants found GoCARB easy to use. Conclusions: This study indicates that the system is able to estimate, on average, the carbohydrate content of meals with higher accuracy than individuals with type 1 diabetes can. The participants thought the app was useful and easy to use. GoCARB seems to be a well-accepted supportive mHealth tool for the assessment of served-on-a-plate meals.

Factors affecting prenatal care use and pregnancy outcome in Texas: A comparative study among and within Black, Anglo, and Hispanic populations

This research project is a study in the field of public health to test the relationships of demographic, socioeconomic, behavioral, and biological factors with (1) prenatal care use and (2) pregnancy outcome, measured by birth weight. It has been postulated that demographic, socioeconomic, and behavioral factors are associated with differences in the use of prenatal care services. It has also been postulated that differences in demographic, socioeconomic, behavioral, and biological factors result in differences in birth weight. This research attempts to test these two basic conceptual frameworks. At the same time, an attempt is made to determine the population groups and subgroups that are at increased risk (1) of using fewer prenatal care visits, and (2) of displaying a higher incidence of low birth weight babies. An understanding of these relationships of the demographic, socioeconomic, behavioral, and biological factors in the use of prenatal care visits and pregnancy outcome, measured by birth weight, will potentially offer guidance in the planning and policy development of maternal and child health services. The research considers four major components of maternal characteristics: (1) Demographic factors. Ethnicity, household size, maternal parity, and maternal age; (2) Socioeconomic factors. Maternal education, family income, maternal employment, health insurance coverage, and household dwelling; (3) Behavioral factors. Maternal smoking, attendance at child development classes, mother's first prenatal care visit, total number of prenatal care visits, and adequacy of care; and, (4) Biological factors. Maternal weight gain during pregnancy.^ The research considers 16 independent variables and two dependent variables.^ It was concluded that: (1) Generally, differences in demographic, socioeconomic, and behavioral factors were associated with differences in the average number of prenatal care visits between and within population groups and subgroups. The Hispanic mothers were the lowest users of prenatal care services. (2) In some cases, differences in demographic, socioeconomic, behavioral, and biological factors demonstrated differences in the average birth weight of infants between and within population groups and subgroups. (3) Differences in demographic, socioeconomic, behavioral, and biological factors resulted in differences in the rates of low birth weight babies between and within population groups and subgroups. The Black mothers delivered the highest incidence of low birth weight infants.^ These findings could provide guidance in the formulation of public health policies such as MCH services, an increase in the use of prenatal care services by prospective mothers, resulting in reduction of the incidence of low birth weight babies, and consequently aid in reducing the rates of infant mortality. ^

A Comparative Study of Development Mechanisms in Korea and Taiwan: Introductory Analysis

This article is the introduction to a special issue of The Developing Economies which presented the results of a research project by the Institute of Developing Economies that examined the development mechanisms in Korea and Taiwan. Our conclusion in this article is that their development mechanisms, despite their similar development patterns of export-led industrialization, have been essentially different: a government-led mechanism in Korea as opposed to a market-led mechanism in Taiwan. We verified this difference through comparative studies of the two economies covering trade balances, the growth of total factor productivity, the scale of enterprises and business groups, and the development processes of individual manufacturing sectors. In our explanatory discussion we propose that the difference in the mechanisms is based on: 1) the amount of accumulation in the economy at the time postwar industrialization started, 2) the relationship between government and society, and 3) the mechanism of social network formation.

Organizational Capability of Local Societies in Rural Development: A Comparative Study of Microfinance Organizations in Thailand and the Philippines

The importance of organizing local people for development work is widely recognized. Both governmental and non-governmental agencies have implemented various projects that have needed and encouraged collective action by people. Often, however, such projects malfunction after the outside agencies retreat from the project site, suggesting that making organizations is not the same as making a system of making organizations. The latter is essential to make rural organizations self-reliant and sustainable. This paper assumes that such a system exists in local societies and focuses on the capacity of local societies for creating and managing organizations for development. It reveals that (1) such capability differs according to the locality, (2) the difference depends on the structure of the organizations that coordinate people's social relations, and (3) the local administrative bodies define, at least partly, the organizational capability of local societies. We compare two rural societies, one in Thailand and the other in the Philippines, which show clear contrasts in both the form of microfinance organizations and the way of making these organizations.