Visual search for natural grains in pigeons (Columba livia): Search images and selective attention.

The experiments reported here were designed to test the suggestion of many researchers that selective attention to visual features of a prey can account for search-image effects. In 3 experiments pigeons ate wheat and vetch grains presented on multicolored and gray gravel trays. In Experiment 1 search-image effects were evident when grains were cryptic but not when they were conspicuous. Experiment 2 demonstrated that search images can be activated when the grains encountered are either cryptic or conspicuous but that search images affect search performance only when the grains are cryptic. Experiment 3 demonstrated that search images are short-term in nature: A 3-min delay between successive encounters with a type of grain disrupted an activated search image. The discussion addresses how these results further develop a model in which search images are viewed as selective attention to visual features of a prey. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An overview of ultra-wideband microwave imaging via space-time beamforming for early-stage breast-cancer detection

Ultra-wideband (UWB) microwave imaging has recently been proposed for detecting small malignant breast tumors. In this article, we review the current research status of this approach. First, we introduce the concept of microwave imaging via space-time (MIST) beamforming and related signal-processing algorithms. The objective of these signal-processing techniques is to form a spatial image of scattered microwave energy, and to identify the presence and location of malignant lesions from their scattering signatures. Next, we present numerical studies based on finite-difference time-domain simulations to demonstrate the efficacy of MIST beamforming for detecting small malignant breast lesions in both prone and supine configurations. Finally, the experimental feasibility of UWB microwave imaging is demonstrated using an initial imaging prototype and multilayered breast phantoms.     

Effects of hydrogen sulfide containing gas condensate on the hepatic microsomal monooxygenase system]

Chronic action of different xenobiotics which form a part of condensed hydrogen sulphide-containing gas causes substantial changes in the activity of xenobiotic metabolic enzymes, which is suggestive of the damaged hepatic microsomal monooxygenase system. As the rate of biotransformation becomes higher, there are increases in the activity of microsomal monooxygenases and in the generation of active oxygen forms and hydrogen peroxide, by impairing antiradical and antiperoxide mechanisms. The experimentally used concentration of substances as constituents of condensed gas corresponds to the maximum acceptable air concentration of in the working area of gas-refining plants, but the functional features of the body's detoxifying system--the hepatic monooxygenase system should be taken into account while developing preventive measures of occupational diseases.     

A phase II trial of interleukin-2 and interferon-alpha in the treatment of metastatic colorectal carcinoma

A total of 29 patients with stage IV colorectal cancer were entered into a phase II trial of bolus interleukin-2 (IL-2) and interferon-alpha (IFN alpha) (3 x 10(6) U/m2 of each cytokine given i.v. q8h x 15 doses and repeated in 2 weeks). Immunologic parameters measured on isolated peripheral blood lymphocytes revealed increased activated T cells with upregulated natural killer and lymphokine-activated killer activity. Among 24 evaluable patients, there were 4 partial responses (17%) of short duration ( < or = 6 months). Three of the responding patients had been refractory to prior chemotherapy. Overall median survival in the 24 evaluable patients was 18.5 months. Therapy necessitated an inpatient setting, with the most common toxicities being hypotension, hepatic insufficiency, fever, hypocalcemia, nausea/vomiting, and renal insufficiency. There were two treatment-related deaths. Because neither IL-2 nor IFN alpha alone has significant activity against colorectal cancer, the responses observed in this study suggest a potential synergistic effect between the two cytokines. However, the toxicity and short duration of response without survival benefit do not support the routine use of this regimen as a therapeutic modality for this tumor histology.     

Administering amphotericin B--a practical approach

Despite the introduction in recent years of novel antifungal agents, the potency and broad spectrum of activity of amphotericin B have ensured that it remains the treatment of choice for most deep-seated mycoses. However, this agent is not without significant toxicity, particularly in patients who are already seriously ill and/or who are receiving other potentially nephrotoxic drugs. We review the various routes by which amphotericin B can be administered, focusing mainly on the intravenous route. The use of more rapid infusion rates, lipid-complexed preparations, sodium supplementation in salt-depleted patients and strategies to reduce the incidence of infusion-related reactions and nephrotoxicity are also considered. Finally, detailed recommendations for the administration of amphotericin B are provided.     

Hypermutability of mouse chromosome 2 during the development of x-ray-induced murine myeloid leukemia

In an effort to identify the precise role of a deletion at regions D-E of mouse chromosome 2 [del2(D-E)] during the development of radiation-induced myeloid leukemia, we conducted a serial sacrifice study in which metaphase chromosomes were examined by the G-banding technique. Such metaphase cells were collected from x-irradiated mice during the period of transformation of some of the normal hematopoietic cells to the fully developed leukemic phenotype. A group of 250 CBA/Ca male mice (10-12 weeks old) were exposed to a single dose of 2 Gy of 250-kilovolt-peak x-rays; 42 age-matched male mice served as controls. Groups of randomly selected mice were sacrificed at 20 hr, 1 week, and then at intervals of 3 months up to 24 months after x-irradiation. Slides for cytogenetic, hematological, and histological examination were prepared for each animal at each sacrifice time. An expansion of cells with lesions on one copy of chromosome 2 was evident in 20-25% of treated mice at each sacrifice time. The majority of such lesions were translocations at 2F or 2H, strongly suggesting hypermutability of these sites on mouse chromosome 2. No lesions were found in control mice. The finding leads to the possibility that genomic lesions close to 2D and 2E are aberrants associated with radiation leukemogenesis, whereas a single clone of cells with a del2(D-E) may lead directly to overt leukemia. The data also indicate that leukemic transformation arises from the cumulative effects of multiple genetic events on chromosome 2, reinforcing the thesis that multiple steps of mutation occur in the pathogenesis of cancer.     

A method for isolation of sequences missing in one of two related genomes

We describe a novel technique for isolation of sequences that are present in one genome (tracer), but absent in another (driver). Tracer DNA, cleaved with Sau 3A and capped with a single stranded PCR adapter, is allowed to hybridize with an excess of sheared biotinylated driver; biotinylated DNA and its hybrids with the tracer are removed by phenol/chloroform extraction after incubation with streptavidin. After several rounds of subtraction the ends of self-annealed tracer molecules from the nonextractable fraction are filled-in with Tag polymerase and amplified, using the single stranded PCR adapter as a primer. The method has been applied to purification of fragments from a 2.9 kb plasmid added to E. coli DNA at equimolar quantity. Plasmid derived fragments (250-1000 bp), initially comprising 1/1400th part of tracer DNA, were purified to homogeneity after two rounds of subtraction followed by PCR.     

A usability evaluation of medical software at an expert conference setting

Introduction

A usability test was employed to evaluate two medical software applications at an expert conference setting. One software application is a medical diagnostic tool (electrocardiogram [ECG] viewer) and the other is a medical research tool (electrode misplacement simulator [EMS]). These novel applications have yet to be adopted by the healthcare domain, thus, (1) we wanted to determine the potential user acceptance of these applications and (2) we wanted to determine the feasibility of evaluating medical diagnostic and medical research software at a conference setting as opposed to the conventional laboratory setting.

Methods

The medical diagnostic tool (ECG viewer) was evaluated using seven delegates and the medical research tool (EMS) was evaluated using 17 delegates that were recruited at the 2010 International Conference on Computing in Cardiology. Each delegate/participant was required to use the software and undertake a set of predefined tasks during the session breaks at the conference. User interactions with the software were recorded using screen-recording software. The ‘think-aloud’ protocol was also used to elicit verbal feedback from the participants whilst they attempted the pre-defined tasks. Before and after each session, participants completed a pre-test and a post-test questionnaire respectively.

Results

The average duration of a usability session at the conference was 34.69 min (SD = 10.28). However, taking into account that 10 min was dedicated to the pre-test and post-test questionnaires, the average time dedication to user interaction of the medical software was 24.69 min (SD = 10.28). Given we have shown that usability data can be collected at conferences, this paper details the advantages of conference-based usability studies over the laboratory-based approach. For example, given delegates gather at one geographical location, a conference-based usability evaluation facilitates recruitment of a convenient sample of international subject experts. This would otherwise be very expensive to arrange. A conference-based approach also allows for data to be collected over a few days as opposed to months by avoiding administration duties normally involved in laboratory based approach, e.g. mailing invitation letters as part of a recruitment campaign.Following analysis of the user video recordings, 41 (previously unknown) use errors were identified in the advanced ECG viewer and 29 were identified in the EMS application. All use errors were given a consensus severity rating from two independent usability experts. Out of a rating scale of 4 (where 1 = cosmetic and 4 = critical), the average severity rating for the ECG viewer was 2.24 (SD = 1.09) and the average severity rating for the EMS application was 2.34 (SD = 0.97). We were also able to extract task completion rates and times from the video recordings to determine the effectiveness of the software applications. For example, six out of seven tasks were completed by all participants when using both applications. This statistic alone suggests both applications already have a high degree of usability. As well as extracting data from the video recordings, we were also able to extract data from the questionnaires. Using a semantic differential scale (where 1 = poor and 5 = excellent), delegates highly rated the ‘responsiveness’, ‘usefulness’, ‘learnability’ and the ‘look and feel’ of both applications.

Conclusion

This study has shown the potential user acceptance and user-friendliness of the novel EMS and the ECG viewer applications within the healthcare domain. It has also shown that both medical diagnostic software and medical research software can be evaluated for their usability at an expert conference setting. The primary advantage of a conference-based usability evaluation over a laboratory-based evaluation is the high concentration of experts at one location, which is convenient, less time consuming and less expensive.     

Surgical anatomy of the greater pectoral muscle

In 41 preparations of the m. pectoralis major it has been stated by means of anatomical methods that the vascular "hilus" is projected on the upper third of its middle part and represented by the thoracic branch of the thoracoacromial artery. The latter has several variants dividing into branches of the successive orders. It has been stated that the muscle has a wide network of anastomoses at the macro-microscopic level. For plastic purposes, it is expedient to use the external and middle parts of the m. pectoralis major which have more favourable conditions of the blood supply. Owing to the data obtained and the technique, developed on 25 corpses, for cutting out and graft transplantation in the thoracic cavity, it has been possible to operate 9 patients.