Single-shot, double-pulse determination of the detonation energy in nanosecond-laser ablation using the blast model.

We demonstrate a novel single-shot method to determine the detonation energy of laser-induced plasma and investigate its performance. This approach can be used in cases where there are significant shot-to-shot variations in ablation conditions, such as laser fluctuations, target inhomogeneity, or multiple filamentation with ultrashort pulses. The Sedov blast model is used to fit two time-delayed shadowgrams measured with a double-pulse laser. We find that the reconstruction of detonation parameters is insensitive to the choice of interpulse delay in double-pulse shadowgraphy. In contrast, the initial assumption of expansion dimensionality has a large impact on the reconstructed detonation energy. The method allows for a reduction in the uncertainties of blast wave energy measurements as a diagnostic technique employed in various laser ablation applications.

Bilberry extract, its major polyphenolic compounds, and the soy isoflavone genistein antagonize the cytostatic drug erlotinib in human epithelial cells.

Erlotinib (Tarceva®) is a chemotherapeutic drug approved for the treatment of pancreatic cancer and non-small cell lung cancer. Its primary mode of action is the inhibition of the epidermal growth factor receptor (EGFR), a receptor tyrosine kinase (RTK). Recently, RTK-inhibiting polyphenols have been reported to interact synergistically with erlotinib. Furthermore some anthocyanidins and anthocyanin-rich berry extracts have been reported to inhibit tyrosine kinases, including the EGFR, which raises the question of potential interactions with erlotinib. Polyphenol-rich preparations such as berry- or soy-based products are commercially available as food supplements. In the present study we tested a bilberry extract, its major anthocyanin and potential intestinal degradation products, as well as genistein, with respect to possible interactions with erlotinib. Cell growth inhibition was assessed using the sulforhodamine B assay, while interactions with EGFR phosphorylation were analyzed by SDS-PAGE/western blotting with subsequent immunodetection. Genistein, bilberry extract, delphinidin-3-O-glucoside and delphinidin were found to antagonize erlotinib whereas phloroglucinol aldehyde was found to enhance cytostatic effects of the drug on human epithelial A431 cells. Genistein also antagonized the EGFR inhibitory effects of erlotinib, whereas bilberry anthocyanins showed no significant interactions in this regard. Our data indicate that different polyphenols are potentially able to impair the cytostatic effect of erlotinib in vitro. Genistein interacts via the modulation of erlotinib-mediated EGFR inhibition whereas bilberry anthocyanins modulated the growth-inhibitory effect of erlotinib without affecting EGFR phosphorylation, thus indicating a different mechanism of interference.

Multiple glucagon-producing pancreatic neuroendocrine tumors in a horse (Equus caballus).

Pancreatic neuroendocrine tumors of glucagon-producing cells are extremely rare in domestic animals. In this report, we describe for the first time, to our knowledge, the incidental finding of multiple glucagon-producing neuroendocrine tumors of the pancreas of a horse. The animal was euthanized due to severe local infection after tooth extraction. On postmortem examination, multiple white nodules of up to 4 cm in diameter were observed in the pancreas. Histologically, pancreatic nodules had the appearance of neuroendocrine neoplasms with positive immunoreactivity for glucagon, synaptophysin, chromogranin A, and neuron-specific enolase. Electron microscopy revealed numerous electron-dense granules, similar to those observed in normal pancreatic alpha cells, in the neoplastic cells. In addition, the left adrenal gland showed multiple hyperplastic foci and adenomas in the medulla that were identified as pheochromocytomas. Based on the morphologic appearance and immunohistochemical staining pattern of pancreatic nodules, a diagnosis of multiple glucagon-producing neuroendocrine tumors was made.

Host specificity of two species of Gnathia (Isopoda) determined by DNA sequencing blood meals.

Host specificity data for gnathiid isopods are scarce because the parasitic stages are difficult to identify and host-parasite contact is often brief. We examined two common nocturnal species, Gnathia falcipenis and Gnathia sp. C, collected in light traps from two locations at Lizard Island on the Great Barrier Reef, Australia. Engorged third stage gnathiids were photographed and permitted to moult into adults to allow identification. We compared approximately 580 bp sequences of 16S mtDNA from blood meals with host sequences available on GenBank using BLASTn. Where homology was <98%, familial identity was investigated with neighbour-joining trees. All blood meal sequences (n=60) and homologous fish sequences (n=87) from GenBank were used in a Bayesian analysis, which identified all but three sequences to family. The host frequency distributions used by each species were significantly different; only four host families were shared. No gnathiids fed on elasmobranchs, blennies or apogonids, and most fed on host families whose representatives are typically large. Gnathia sp. C showed a distinct predilection for nemipterids. Gnathia falcipenis often parasitised sand-dwelling families, and unlike sympatric diurnal gnathiid species, it also frequently parasitised pomacentrids. We conclude that G. falcipenis and Gnathia sp. C operate as generalist micropredators with preferences.

A simple molecular technique for identifying marine host fish by sequencing blood-feeding parasites.

Gnathiid isopods are common ectoparasites of fish on the Great Barrier Reef, Australia. While screening for appropriate markers for phylogenetic studies of gnathiids, we found that primers for 12S and 16S rDNA preferentially amplified the host fish DNA instead of gnathiid DNA. This amplification occurred even when using gnathiids that were not engorged with host blood and adult gnathiids that do not feed on fish blood. This method could be used in host-parasite studies to identify hosts without having to sample parasites directly from the host (which can be costly and requires considerable skill in a marine environment). Target ribosomal DNA sequences can be amplified from total DNA extracted from parasites that are captured in funnel traps or plankton tows. Sequence data from these can be used to identify the hosts that gnathiids were feeding on before capture.

Determining the displacement of the pelvic floor and pelvic organs during voluntary contractions using magnetic resonance imaging in younger and older women.

OBJECTIVES: To: (i) visualize the effect of sustained voluntary contractions on the anatomical configuration of the pelvic floor (PF) muscles using magnetic resonance imaging (MRI); (ii) examine the effect of ageing on the range of displacement of the PF contents secondary to contraction and simulating incontinence exercises; and (iii) introduce the concept of contractile change in volume (DeltaPF-V) using three-dimensional (3D) reconstruction from axial, sagittal and coronal MRI. SUBJECTS AND METHODS: Two groups of continent women volunteers, familiar with correct PF contraction, were evaluated. The mean (sd) age in group I was 34 (6) years and that of group II 55 (9) years; the mean parities were 0.7 and 2.2, respectively. MRI was conducted with the women supine and data were obtained in the axial, sagittal and coronal planes. In each plane, images were obtained with the PF relaxed and subsequently with the PF contracted over 10-20 s. Image processing was used to enhance the anatomical boundaries of the pelvic organs and to measure the displacement produced by the contraction. Displacements, observed between each image pair, were colour-coded to highlight the geometric differences between a relaxed and contracted PF and to facilitate measuring displacement. Data measured from each group were pooled and the range of motion expressed as the mean (sd), compared using Student's t-test. RESULTS: Digitally processed imaging allowed an accurate comparison between the relaxed and contracted PF, and highlighted the differences between them. From these views, the levator ani displaced the vagina asymmetrically in nine of the 11 older subjects, and in six of the 17 younger subjects. The values from the imaging in the sagittal and coronal plane for the two groups were: levator ani displacement, 7.4 (1.1) and 1.4 (0.2) cm (P < 0.002), superior bladder wall, 4.2 (0.5) and 1.0 (0.1) cm (P < 0.002). There were also significant differences in the range of displacement produced by voluntary PF contraction in the internal structures; external outlines did not reflect these changes. The maximum displacement of the gluteal surface in the coronal plane did not change significantly; in group I it was 3.9 (1.8) to 2.9 (0.7) cm. From the 3D re-construction, DeltaPF-V for the younger women was significantly larger, at 23.3 (3.9) mL (P < 0.01) than in the older women, at 9.1 (4.4) mL. CONCLUCION: The range of motion over which voluntary PF contractions displace the bladder and vagina is age-dependent, being higher in younger than in older subjects. It remains to be established whether range of movement is a limitation caused by neuronal factors, decrease in muscle strength/mass, or the substitution of spaces with fat (restricting free movement), or other factors.

Natural selection and parallel speciation in sympatric sticklebacks.

Natural selection plays a fundamental role in most theories of speciation, but empirical evidence from the wild has been lacking. Here the post-Pleistocene radiation of threespine sticklebacks was used to infer natural selection in the origin of species. Populations of sticklebacks that evolved under different ecological conditions show strong reproductive isolation, whereas populations that evolved independently under similar ecological conditions lack isolation. Speciation has proceeded in this adaptive radiation in a repeatable fashion, ultimately as a consequence of adaptation to alternative environments.

Practice patterns of acute care nurse practitioners.

This study was undertaken to examine the practice pattern of nurse practitioners employed in Ontario acute care settings. A descriptive design, incorporating quantitative and qualitative methods for data collection, was used. The acute care nurse practitioners' practice pattern varied in terms of scope of practice, model guiding practice, reporting relations, and extent of role implementation. Role implementation encompassed activities representing the four role components: clinical practice, education, administration or management, and research. The acute care nurse practitioners engaged most frequently in the clinical component of the role. They performed medical and advanced nursing functions. They emphasized that they do not work in isolation and that they do not replace physicians or residents.

Organizational factors influencing nurse practitioners' role implementation in acute care settings.

The purpose of this study was to explore the influence of organizational factors on the Acute Care Nurse Practitioner (ACNP) role implementation. A descriptive correlational design, incorporating quantitative and qualitative methods for data collection was used. The sample of convenience consisted of 57 ACNPs assigned to various medical and surgical programs within acute care hospitals. Ten ACNPs participated in the unstructured qualitative interviews. In addition to the interviews, data pertinent to various organizational factors, including role formalization, receptivity of the role by others, perceived autonomy, role strain, and additional factors that may interfere with role implementation, were collected through a self-report structured questionnaire. A four-diary day was completed to gather data on role implementation. Descriptive and correlational statistics were used to analyze the quantitative data. The qualitative data were content analyzed. The ACNPs engaged most frequently in activities reflective of the clinical practice component of the role and less frequently in the non-clinical components (i.e., education, administration, and research). Results of the quantitative and qualitative analyses indicated that lack of formal clear job description, conflicting demands and expectations, lack of receptivity of the role by others, lack of autonomy, and increased workload were negatively correlated with the ACNP role implementation. The ACNP role implementation varies across practice settings. This variability should be accounted for when examining outcomes of ACNP care.

Sterilization for family planning in a Third World country.

Outpatient laparoscopy procedures have made sterilization possible for millions of women in developing countries. This report describes the experience of a team of doctors, nurses, and support staff that performed 107 laparoscopic tubal sterilizations during on eight-day sojourn in a remote north-central area of Nicaragua. Minimal analgesia (oral ibuprofen) and anesthesia (1% lidocaine) were used since most of the patients walked to and from the hospital-some up to 15 miles. Because the Nicaraguan government's support for birth-control programs is unreliable and because illegal abortion is the leading cause of maternal mortality in Nicaragua, this safe, minimally invasive surgical method is the favored means of birth control.

PIP: During an 8-day visit to Jalapa, Nicaragua, in 1996, a Short-Term Volunteers in Mission team from Minnesota, US, performed 107 outpatient laparoscopic sterilizations and 14 vasectomies in this remote town near the Honduran border. Standard medical procedures were modified to adapt to the inadequate medical facilities and large patient load. The mean age of female sterilization acceptors was 28.92 years; they had an average of 4.4 living children. 75% lived in or near the town and walked a total of 1 hour or less to and from the hospital; another 20% walked an average of 4 hours round trip. Because of the women's need to walk home after the procedure, local anesthesia (1% lidocaine) was administered in conjunction with oral ibuprofen. More than 75% of acceptors experienced mild or no intraoperative pain and were sent home right after the procedure; 20% reported moderate pain and 3% severe pain, but in all cases the pain dissipated within 10-45 minutes. The length of time from admission to discharge averaged 45 minutes (range, 25-75 minutes). Civil war, overpopulation, and severe poverty limit the ability of government-sponsored programs to deliver family planning services consistently. Thus, sterilization is an ideal method of fertility control for appropriate candidates.

Students' self-reported substance use by grade level and gender.

Over 900 students in the rural northwest at the fourth, sixth, eighth, and tenth grade levels were surveyed for alcohol and drug use. The survey instrument measured self-reported usage of seventeen substances. The descriptive statistical results are reported by gender as well as grade-level usage rates. Discussion includes targeting drug prevention programs for specific grade and gender levels based upon the results.

Students' self-reported substance use by grade level and gender.

Over 900 students in the rural northwest at the fourth, sixth, eighth, and tenth grade levels were surveyed for alcohol and drug use. The survey instrument measured self-reported usage of seventeen substances. The descriptive statistical results are reported by gender as well as grade-level usage rates. Discussion includes targeting drug prevention programs for specific grade and gender levels based upon the results.

Behavior assessment and cross-validation by surrogate measures in drug prevention research.

When used with more orthodox survey or interview techniques, surrogate measures can enhance a study's credibility. Presented is a case report which illustrates the viability of using a surrogate measure to cross-validate self-reports of alcohol consumption by members of a fraternity at a large Midwestern university. As federal authorities continue to scrutinize myriad ways to reduce the nation's health care burden drug abuse research will have an enhanced opportunity to justify its role in that movement. The historical reliance on self-report methods which lack supportive, corroborating evidence of behavior change may jeopardize preventive drug education's opportunity to play a more integral part in influencing health promotion policies.

Viroid replication: equilibrium association constant and comparative activity measurements for the viroid-polymerase interaction.

The binding and replication of purified potato spindle tuber viroid (PSTV) by DNA-dependent RNA polymerase II from wheat germ was studied in analytical ultracentrifugation experiments and in vitro transcription assays. The equilibrium association constant for the viroid-polymerase interaction is 1.9 X 10(7) M-1. Both ultraviolet and fluorescent monitoring during the sedimentation experiments showed two distinguishable viroid-polymerase complexes. These are interpreted as resulting from a 1:1 and 2:1 enzyme-to-viroid binding stoichiometry. A265/A280 ratios across the sedimenting boundaries, the sedimentation velocity of the complexes, as well as electron microscopic data support this interpretation. The role of viroid secondary structure in enzyme binding and polymerization is discussed in the light of these results and compared with binding and polymerization data for virusoid RNA, single- and double-stranded RNA, and double-stranded DNA.

Dynamics and interactions of viroids.

Viroids are single stranded circular RNA molecules of 120,000 daltons which are pathogens of certain higher plants and replicate autonomously in the host cell. Virusoids are similar to viroids in respect to size and circularity but do replicate only as a part of a larger plant virus. The structure and structural transitions have been investigated by thermodynamic, kinetic and hydrodynamic methods and have been compared to results from calculations of the most favorable native structures and the denaturation process. The algorithm of Zuker et al. was modified for the application to circular nucleic acids. For viroids the calculations confirm our earlier theoretical and experimental results about the extended native structure and the highly cooperative transition into a branched structure. Virusoids, although described in the literature as viroid-like, show less base pairing, branching in the native secondary structure, and only low cooperativity during denaturation. They resemble more closely the properties of random sequences with length, G:C content, and circularity as in viroids but sequences generated by a computer. The comparison of viroids, virusoids and circular RNA of random sequences underlines the uniqueness of viroid structure. The interactions of viroids with dye and oligonucleotide-ligands and with RNA-polymerase II from wheat germ, which enzyme replicates viroids in vitro, has been studied in order to correlate viroid structure and its ability for specific interactions. Specificity of the interactions may be interpreted on the basis of the neighbourhood of double stranded and single stranded regions. In the host cell viroids are localized in the cell nucleus; they may be detected as free nucleic acids and in high molecular weight complexes together with other RNA and proteins.

Lucid dreaming verified by volitional communication during REM sleep.

SUMMARY: The occurrence of lucid dreaming (dreaming while being conscious that one is dreaming) has been verified for 5 selected subjects who signaled that they knew they were dreaming while continuing to dream during unequivocal REM sleep. The signals consisted of particular dream actions having observable concomitants and were performed in accordance with pre-sleep agreement. The ability of proficient lucid dreamers to signal in this manner makes possible a new approach to dream research--such subjects, while lucid, could carry out diverse dream experiments marking the exact time of particular dream events, allowing derivation of of precise psychophysiological correlations and methodical testing of hypotheses.

Mixed and obstructive sleep apnea and near miss for sudden infant death syndrome: 2. Comparison of near miss and normal control infants by age.

Twenty-nine full-term near miss for sudden infant death syndrome (SIDS) and 30 normal control infants underwent 24-hour polygraphic monitoring. Several types of respiratory events during sleep (eg, central, mixed, and obstructive apnea, periodic breathing) were defined and tabulated. Analysis of these respiratory variables and comparison of groups of near miss and control infants indicated that between 3 weeks and 4 1/2 months of age only one variable was consistently different at a statistically significant level: the number of mixed and obstructive apnea greater than 3 seconds during total sleep time. This study also showed an increase in mixed and obstructive respiratory events during sleep at 6 weeks of age in control as well as in near miss infants.

Obstructive sleep apnea and near miss for SIDS: I. Report of an infant with sudden death.

An infant girl followed up from birth to death at the University Medical Center had ""congenital stridor'' and a ""near miss for SIDS'' event at 3 months of age. As part of an ongoing SIDS research project, she underwent 24-hour polygraphic monitoring at 21 weeks of age. Sudden infant death occurred within 30 hours after the polygraphic study. Polygraphic data obtained from this infant are compared with those from control infants and other infants with near miss for SIDS who were of similar ages. The number of mixed and obstructive respiratory events during sleep was abnormally high on the infant's recording. Histologic findings, involving particularly the midline structures of the brain stem, are discussed.