Search

Quasi-1D van der Waals materials, such as transition metal trichalcogenides, have strong covalent bonds in one direction and weaker bonds in cross-plane directions. They can be prepared as crystalline nanowires or nanoribbons consisting of 1D atomic threads, i.e., chains. We have examined the current carrying capacity of ZrTe3 nanoribbons using a set of structures fabricated by the shadow mask method. The bulk crystals were synthesized by the chemical vapor transport method and exfoliated onto Si/SiO2 substrates. It was found that ZrTe3 nanoribbons reveal an exceptionally high current density, on the order of ~100 MA/cm2, at the peak of the stressing DC current. The low-frequency noise was of 1/ ${f}$ type near room temperature ( ${f}$ is the frequency). The noise amplitude scaled with the resistance, following the trend established for other low-dimensional materials. The high current density in ZrTe3 can be attributed to the single-crystal nature of quasi-1D van der Waals materials. [ABSTRACT FROM AUTHOR]

This essay attempts to study Augustines political thought in The City of God De Civitate Dei. It will demonstrate that the notion of pilgrimage is essential for understanding the political thought that Augustine develops in The City of God. To support the thesis, I will explore what role the theme of pilgrimage plays in Augustines formulation of anthropology, ecclesiology, and political thought in The City of God. Augustines ideas of pilgrimage stem from his pilgrim eschatology, which regulates the entire political aspect of the Christians life. Augustine does not lay any neutral realm between the city of God and the earthly city. The political work of pilgrims of the city of God for the citizens of the earthly city is associated with evangelism persuasion to love God, peace the mutual aim of the two cities, justice which starts from true worship, and prayer which is intending toward the final perfection. [ABSTRACT FROM AUTHOR]

The ethics of Wolfhart Pannenberg has a nomological dimension at its center. Based on the history of the natural law tradition, Pannenberg maintains the possibility of the natural law theory on the following five grounds. The theological ground is his understanding of the Decalogue, the Sermon on the Mount, and the Pauline interpretation of the law. For its historical ground, Pannenberg articulates the natural law theories of Patristic theology and the theologies of Troeltsch and Brunner. The ontological ground is the order of the world, which God established in the process of history. The anthropological ground is the mutuality of human society. The latter two dimensions are related to the epistemological ground, which is based on the hermeneutics of universal history. Pannenberg attempts to combine the law, the gospel, and love in relation to the Kingdom of God. Thus, Pannenberg’s Kingdom ethics is nomological as well as eschatological. [ABSTRACT FROM PUBLISHER]

Abstract Objectives: To calibrate and validate a digital subtraction radiography system using scanned images for quantification of alveolar bone changes by means of computer-assisted densitometric image analysis (CADIA) in vitro. Materials and Methods: Noise levels were determined using 10 standardized periapical radiographs of the same lower molar region in a human dry skull. For validation of the system, radiographs were taken before and after bovine bone particles in measures with increments of 2 mg weighing from 2 to 20 mg were added into each socket of three dry skulls. Radiographs were developed and scanned into a computer with a flatbed scanner. After digitization, the images were subjected to alignment, normalization and subtraction. Appropriate regions of interest (ROIs) were selected and their CADIA values were calculated for the determination of noise levels, and correlations between the CADIA values and the actual bone mass were performed. Results: When the threshold value was 7, the percentage of pixels deviating from the set threshold value was small (0–11.3%). There were statistically significant correlations between the actual bone mass and the CADIA value for anterior sockets (p <0.001, r 2 =0.89) and posterior sockets (p <0.001, r 2 =0.9). For pooled data of both anterior and posterior sockets, the correlation was also statistically significant (p <0.001, r 2 =0.88). Conclusions: A high and statistically significant correlation between the actual bone mass and CADIA value was obtained, which suggests that the system could be suitable for the detection of small alveolar bone changes. [ABSTRACT FROM AUTHOR]

A mistletoe lectin was isolated from water extracts of Korean mistletoe, a subspecies of Viscum album, grown on Quercus mongolica using CM-Sepharose chromatography followed by an affinity chromatography on a concanavalin A-Sepharose column. The compound proved to be a mistletoe lectin II with D-galactose and N-acetyl-D-galactosamine specificity. Matrix-assisted laser desorption time-of-flight mass spectroscopy showed it to have an average molecular mass of 62.7 kDa and to consist of two subunits of 30.6 kDa and 32.5 kDa. It was a basic protein with isoelectric points of 9.4 and 9.6 by capillary isoelectric focusing and was cytotoxic to Molt4 cell. [ABSTRACT FROM AUTHOR]

Following the theory of surface recombination in semiconductors, we have derived an expression for the rate of ion recombination at the membrane surface. The surface recombination rate is used in the boundary conditions of current flows at the interfaces. Expressions for the ion fluxes are then derived as functions of environmental variables and membrane parameters. Our analysis strongly suggests that the ion flow through a thin lipid membrane consists of two major components: the surface barrier jumping current and the surface recombination current that are controlled decisively by surface barrier height, surface trap density and surface recombination rates. These general formulations are useful not only for the calculation but also for the understanding of ion transport in thin lipid membranes under a variety of experimental conditions. The implications of this theory to biological membranes and its possible extensions are discussed. [ABSTRACT FROM AUTHOR]

In the theory as presented in this paper and the following one, we shall attempt to apply the semiconductor principles and methods to the study of ion transport in thin lipid membranes. Detailed formulations are given on the potential energy barriers at the interfaces, voltage drops in the polar and non-polar regions, and potential and field distributions in the diffuse double layer and within a charged membrane. These results will be used mainly as the boundary conditions for the solution of ion flow as to be given in the following paper. The analysis clearly indicates that the ion transport is interface-limited and is profoundly influenced by the presence of surface charges. An explanation of Na extrusion in nerve membrane is given based on the field distribution analysis. The theory also suggests that the 'membrane potential' depends mainly on surface charges but not necessarily on ion permeation through the membrane. [ABSTRACT FROM AUTHOR]

We developed a required, longitudinal course for first-year medical students that addressed the patient-doctor relationship. Our course linked understanding patients' experiences and perspectives on illness with listening to, talking with, and establishing a rapport with patients while obtaining their medical histories. Learning was enhanced by use of an interdisciplinary faculty and by small-group continuity and faculty mentoring. Our curriculum adapted problem-based, self-directed educational methods to convey medical humanism. We focused on bedside interviewing as the means for exploring patients' social, emotional, and ethical concerns. [ABSTRACT FROM AUTHOR]

Objective: To compile information of the type of Congenital Heart Disease (CHD), the concomitant presence of extra-cardiac structural defect and chromosomal abnormality in our center to assist patient counseling. The true positive rate (TPR) and positive predictive value (PPV) of the prenatal screening of various CHD is calculated. Methods: A single center, prospective, cross-sectional observational study of screening scans on low risk patients. A search of all the cases with CHDs from June 1996 to May 1999 yield a total of 226 cases of confirmed CHDs identified by postmortem examinations, surgery or neonatal 2D echocardiography. Results: The commonest defect is ventricular septal defect (VSD) and/or atrial septal defect (ASD) (75 cases), followed by Fallot's tetralogy/double outlet right ventricle (DORV) (31), pulmonary stenosis/atresia (14), hypoplastic left heart (12), tubular hypoplasia (9), atrio–ventricular septal defect (AVSD) (8) and Ebstein anomaly (8). The TPR differ for individual defect, ranging from 100% for hypoplastic left heart, hypoplastic right heart and Ebstein anomaly to 0% for truncus arteriosus and tubular hypoplasia. The PPV vary for the individual defects, ranging from 100% for Ebstein anomaly, coarctation of aorta, pulmonary stenosis, atrial septal defect and single ventricle to 0% for truncus arteriosus. The presence of a prenatally diagnosed CHD is associated with an increased risk of chromosomal abnormalities from 85.7% for AVSD and 57.1% for coarctation of aorta to 14.3% for Ebstein anomaly. Extra-cardiac defects are common in fetuses with chromosomal disorder. Conclusion: CHD is the commonest defect in the fetus and should be routinely screened for. Availability of de facto information in a diagnostic center is essential to help the mothers to come to an informed decision. Karyotyping should be routinely offered. Extra-cardiac lesions are common associations and should be carefully looked for. An acceptable positive... [ABSTRACT FROM AUTHOR]

Objective: The clinical significance of antenatal ultrasound diagnosis of the absent inferior cerebellar vermis (AICV), whether isolated or associated with other ultrasound findings, has not been well-understood with limited research previously. Because of its association with some syndromes, e.g. Dandy–Walker or Walker–Warburg syndromes, we aim to study the outcome for the purpose of counseling of parents when this is diagnosed antenatally. Methods: A single-center, prospective observational study of screening scans of a low risk population was conducted from 1 October 1996 to 30 September 2000. Cases of AICV diagnosed were followed up postnatally for up to 4 years with cranial ultrasound and developmental assessments. Results: There were 56 746 screening scans on 64 225 babies delivered during this period. Twenty-eight cases of AICV were diagnosed between 19 and 34 weeks. Six had isolated AICV and all occurred in women less than 35 years old. All had normal outcome and developmental assessment on follow up. The other 22 were associated with other ultrasound findings like echogenic bowel, structural heart defects or Dandy–Walker malformation. Four of them occurred in mothers 35 years and older with three (75%) having abnormal karyotype. Five occurred in mothers aged 30–34 years with two (40%) having abnormal karyotype. Of the remaining 13 in those less than 30 years, five (38%) had abnormal karyotype. These include trisomy 13 and 18, Turner and Goldenhar syndrome. Conclusion: The antenatal diagnosis of the isolated AICV is associated with low risk of chromosomal abnormalities and thus, does not require further karyotypic analysis. However, if other ultrasound findings are also seen, an abnormal karyotype can be expected in up to 38% of the patients (in our series), and even more (75%) if the maternal age is 35 years and above. Karyotyping should be offered in these cases. [ABSTRACT FROM AUTHOR]

Purpose: To determine if chromosomal abnormalities are associated with isolated OC (cleft-lip or palate) detected by sonographers trained to perform level two fetal structural surveys in a low risk obstetric population. Methods: A prospective observational study was conducted on women undergoing screening ultrasonography between 18 and 34 weeks from 1 October 1996 to 30 September 2000 in a single maternity unit. Obstetric and neonatal charts were reviewed in all cases where OC in isolation were detected by ultrasonography. Antenatally missed cases of isolated OC were also analyzed. Results: There were 64 225 deliveries in this period. Follow up was complete for 40/42 cases of isolated OC detected by ultrasonography. Unilateral, bilateral and central OC accounted for 30, 12, 0 cases, respectively. Karyotyping was performed in 11 cases; nine cases had normal chromosomes, one had 46XY, 16qh+ (same as mother's) and another had 46XX, t (2; 10) (q33; p12.2) (parental karyotype normal). In both cases with chromosomal aberrations, isolated unilateral cleft-lip and palate were confirmed at delivery. Termination of pregnancy was performed for the latter; whether the balanced translocation would have contributed to an adverse outcome remains unknown. Six newborns had associated abnormalities at delivery: moderate VSD, mild pulmonary stenosis, bilateral clubfeet, Peter's anomaly and two cases of polydactyly. Except for one case of polydactyly which had no karyotyping, the other five had normal chromosomes. Karyotyping was deemed unnecessary by the neonatologist for 27 newborns with confirmed isolated OC. One newborn had no OC (PPV 39/40 = 97.5%). After excluding all cases where associated structural abnormalities were noted at birth, the sensitivity of detecting isolated OC confirmed at delivery was 33/40 (82%). Conclusions: Isolated OC detected by routine ultrasonography in a unit with high sensitivity is associated with a 1/40 (2.5%) risk of a significant chromosomal... [ABSTRACT FROM AUTHOR]

Objective: To study the clinical outcome of cases of choroid plexus cysts (CPC), the prognostic factors that increase the risk of aneuploidy and to formulate a counseling strategy for CPC. Study design: Cases of CPC detected at screening ultrasonography (between 18 and 24 weeks gestation) from 1 October 1996 to 30 September 2000 in low risk antenatal patients at KK Women's & Children's Hospital, Singapore, were studied. The risk of aneuploidy and postnatal cranial ultrasonography of the cases were analyzed. Data was stratified according to maternal age, size of CPC, unilaterality or bilaterality and presence of concomitant structural abnormalities and/or ultrasound markers (non-isolated). Results: There were 485 cases with CPC among 56 746 patients (incidence 0.08%). Overall risk of aneuploidy was 6.2%. There were 30 cases of chromosomal abnormalities including 23 cases of trisomy 18; five cases of trisomy 21; one case of monosomy X and one case of Klinefelter syndrome. Cases of non-isolated CPC were at significantly higher risk for aneuploidy (56.8%) compared to isolated CPC (1.4%), P < 0.001. No significant difference in risk was detected between unilateral and bilateral isolated CPC (P = 0.4), and with increasing size of isolated CPC. A near significant increase in risk was found between the under-30 age group (0.37%) and the above-30 age group. (2.3%) (P = 0.07). In non-isolated CPC, the risk of aneuploidy ranged from 14.3% at age 20–24 and 100% at age 41–45. Likelihood ratio for trisomy 18 was 7.2 for isolated CPC, 1276 for non-isolated CPC and 0.54 for absent CPC in the whole scanned population. Conclusion and recommendations: Our results support the need for a thorough ultrasound anatomic survey for all cases of diagnosed CPC. Karyotyping should be offered to all cases of non-isolated CPC. In isolated CPC, there may be benefit from offering karyotyping when maternal age exceeds 30. [ABSTRACT FROM AUTHOR]