Functional CD4 T cell subset interplay in an intact immune system

Immunization with human collagen IV has been shown to lead to the selective activation of Th-1 and Th-2-like cells in vivo depending on the I-A genotype of the mice. Mice expressing I-As generate Th-1 cells, and mice expressing I-Ab generate Th-2 cells after immunization. We examined the response of (bxs)F1 hybrid mice to determine the types of CD4 T cell activated. We found that Th-1-like responses dominated, in that CD4 T cells from human collagen IV-primed mice displayed good proliferative responses and little ability to induce antibody formation, and secreted IFN-gamma and not IL-5. Most of the Th-1-like activity of F1 hybrid T cells was I-As restricted. Inhibition of Th-1 cell priming using anti-I-As antibody administered with the priming Ag in vivo revealed Th-2-like activity, in that the CD4 T cells now secreted IL-5 and not IFN-gamma and induced antibody formation. Additional studies indicated that anti-IFN-gamma treatment in vivo also revealed Th-2 cells, suggesting that I-As-restricted CD4 T cells producing or controlling the production of IFN-gamma suppress Th-2 priming.     

Rural water supplies: what ways and means?

The development of rural water supplies in Finland is outlined, with particular reference to consumer-managed cooperatives. Lessons are drawn which could be of value in developing countries.     

Pulse stream VLSI circuits and systems: the EPSILON neural network chipset

An analogue CMOS VLSI neural processing chip has been designed and fabricated. The device employs "pulse-stream" neural state signalling and is capable of computing some 360 million synaptic connections per second. In addition to basic characterisation results, the performance of the chip in solving "real-world" problems is also demonstrated. The experience gained from the development of this device has resulted in the design of a second "pulse-stream" chip with improved performance and features. It is anticipated that this second device will be integrated into a standard bus-based system and find early application in robotic control.     

Anomia as a marker of distinct semantic memory impairments in Alzheimer's disease and semantic dementia.

Objective: Many neurologically constrained models of semantic memory have been informed by two primary temporal lobe pathologies: Alzheimer's disease (AD) and Semantic Dementia (SD). However, controversy persists regarding the nature of the semantic impairment associated with these patient populations. Some argue that AD presents as a disconnection syndrome in which linguistic impairment reflects difficulties in lexical or perceptual means of semantic access. In contrast, there is a wider consensus that SD reflects loss of core knowledge that underlies word and object meaning. Object naming provides a window into the integrity of semantic knowledge in these two populations. Method: We examined naming accuracy, errors and the correlation of naming ability with neuropsychological measures (semantic ability, executive functioning, and working memory) in a large sample of patients with AD (n = 36) and SD (n = 21). Results: Naming ability and naming errors differed between groups, as did neuropsychological predictors of naming ability. Despite a similar extent of baseline cognitive impairment, SD patients were more anomic than AD patients. Conclusions: These results add to a growing body of literature supporting a dual impairment to semantic content and active semantic processing in AD, and confirm the fundamental deficit in semantic content in SD. We interpret these findings as supporting of a model of semantic memory premised upon dynamic interactivity between the process and content of conceptual knowledge. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Reproductive wastage in the androstenedione-immune ewe

An experiment was carried out using 320 adult Merino ewes to examine the effects of immunization against an androstenedione human serum albumin conjugate (Fecundin) on ovulation rate, fertilization rate and embryo viability at days 2, 9 and 13-14 after fertilization. The ovulation rate of immunized ewes (2.19 +/- 0.06) was greater (P < 0.001) than that of control ewes (1.43 +/- 0.04). The recovery rate of embryos or of unfertilized oocytes on day 2 was reduced in immunized ewes, but fertilization rate of recovered oocytes was unaffected by immunization. The mean number of normal embryos per ewe pregnant (prolificacy) was higher and the proportion of ewes pregnant (fertility) was lower in immunized than in the control ewes. The distribution of the number of cells per embryo showed no differences in developmental age over the period of sampling, the majority of embryos at this time being at the two- to four-cell stage of development. At day 9 of pregnancy, blastocyst recovery rates were lower in immunized than in control ewes. About 90% of blastocysts recovered were developing normally in control ewes compared with 64% in immunized ewes. The majority of blastocysts recovered on day 9 had hatched from the zona pellucida prior to recovery (mean values were 94.2% and 87.8% for control and immunized groups, respectively). In control ewes single blastocysts were larger than twin blastocysts, but for the immunized ewes this difference was not significant. Both single blastocysts (P < 0.01) and twin blastocysts (P < 0.05) from immunized ewes were smaller than those from control ewes.(ABSTRACT TRUNCATED AT 250 WORDS)     

The value of frozen section examination in planning surgery for follicular thyroid neoplasms

Frozen section examination of follicular neoplasms of the thyroid has been claimed to be of little value in planning the extent of surgery. Clinical factors such as age, sex and tumour size are said to be more accurate predictors of malignancy. The aim of this study was to examine the respective value of clinical factors and frozen section in the surgical management of follicular thyroid neoplasms. A retrospective study of 735 patients with follicular neoplasms treated at Royal North Shore Hospital was undertaken. Factors assessed included clinical features, such as age and sex of the patients and tumour size, as well as findings at frozen section examination. No significant difference in sex distribution was demonstrated when comparing follicular adenoma with follicular carcinoma. There was a significant difference with respect to patient age between the two groups, but the large overlap in the distribution made this difference of no clinical value. In addition, there was no significant difference in tumour size when comparing follicular adenoma with carcinoma. On the other hand, review of frozen section results showed that 40% of patients with follicular carcinoma were positively identified by frozen section examination at initial surgery, with a false positive rate of less than 0.2%. It appears that clinical factors, such as age, sex and tumour size, are of little assistance in differentiating benign from malignant follicular neoplasms. Frozen section examination remains the most definitive tool in planning intra-operatively the extent of surgery for follicular neoplasms of the thyroid.     

Five Views of the Common Body of Knowledge

Abstract

September 11, 2001, will be indelibly stamped upon all our memories. It taxed our emotional foundation and tested the very mettle upon which our country was built. It also provided a most compelling reason for having a viable and executable business continuity planning (BCP) process. No longer will most corporate executives question the need for recovery planning. In fact, the very opposite is unfolding in corporations around the world. Boards of directors are now asking for an assessment of their recovery capabilities and want to understand their exposure.     

Data Transmission Over Networks for Estimation and Control

We consider the problem of controlling a linear time invariant process when the controller is located at a location remote from where the sensor measurements are being generated. The communication from the sensor to the controller is supported by a communication network with arbitrary topology composed of analog erasure channels. Using a separation principle, we prove that the optimal linear-quadratic-Gaussian (LQG) controller consists of an LQ optimal regulator along with an estimator that estimates the state of the process across the communication network. We then determine the optimal information processing strategy that should be followed by each node in the network so that the estimator is able to compute the best possible estimate in the minimum mean squared error sense. The algorithm is optimal for any packet-dropping process and at every time step, even though it is recursive and hence requires a constant amount of memory, processing and transmission at every node in the network per time step. For the case when the packet drop processes are memoryless and independent across links, we analyze the stability properties and the performance of the closed loop system. The algorithm is an attempt to escape the viewpoint of treating a network of communication links as a single end-to-end link with the probability of successful transmission determined by some measure of the reliability of the network.     

Functionalized graphene as an aqueous phase chemiresistor sensing material

Here we report on the successful detection of benzene, toluene, ethylbenzene, xylenes and cyclohexane dissolved in water at low ppm concentration levels using functionalized graphene in a microelectrode chemiresistor platform. The use of microelectrodes results in a small double layer capacitance that effectively impedes charge transfer through the solution and allows the resistance of the graphene film to be measured preferentially. Comparing the relative chemiresistor response between cyclohexane (a non-aromatic molecule) and aromatic compounds (e.g. toluene), we have deduced that the response mechanism is most likely due to film swelling and not doping through the direct interaction of the molecule with the graphene basal plane.