Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Oxygen-insensitive nitroreductases of Escherichia coli do not reduce 3-nitrotyrosine

The oxygen-insensitive nitroreductases nfsA and nfsB are known to reduce para-nitrated aromatic compounds. We tested the hypothesis that these nitroreductases are capable of reducing 3-nitrotyrosine in proteins and peptides, as well as in free amino acids using wild-type and nfsA nfsB mutant strains of Escherichia coli. E. coli homogenates were incubated with nitrated proteins and the level of 3-nitrotyrosine immunoreactivity was assayed by Western blotting. Assay conditions that allow the nitroreductases to rapidly reduce nitrofurantoin did not result in the modification of 3-nitrotyrosine in protein, peptide, or free amino acid. Stimulation of nfsA nfsB activity with paraquat had no effect on 3-nitrotyrosine reduction. Nonlethal exposure of E. coli to peroxynitrite/CO(2) resulted in the reproducible nitration of tyrosine residues in endogenous proteins. The degree of 3-nitrotyrosine immunoreactivity over the 2-h postexposure period did not differ between mutant and wild-type strains. These results indicate that the nfsA and nfsB enzymes do not reduce 3-nitrotyrosine.

Carotid chemoreceptors tune breathing via multipath routing: reticular chain and loop operations supported by parallel spike train correlations

We tested the hypothesis that carotid chemoreceptors tune breathing through parallel circuit paths that target distinct elements of an inspiratory neuron chain in the ventral respiratory column (VRC). Microelectrode arrays were used to monitor neuronal spike trains simultaneously in the VRC, peri-nucleus tractus solitarius (p-NTS)-medial medulla, the dorsal parafacial region of the lateral tegmental field (FTL-pF), and medullary raphe nuclei together with phrenic nerve activity during selective stimulation of carotid chemoreceptors or transient hypoxia in 19 decerebrate, neuromuscularly blocked, and artificially ventilated cats. Of 994 neurons tested, 56% had a significant change in firing rate. A total of 33,422 cell pairs were evaluated for signs of functional interaction; 63% of chemoresponsive neurons were elements of at least one pair with correlational signatures indicative of paucisynaptic relationships. We detected evidence for postinspiratory neuron inhibition of rostral VRC I-Driver (pre-Bötzinger) neurons, an interaction predicted to modulate breathing frequency, and for reciprocal excitation between chemoresponsive p-NTS neurons and more downstream VRC inspiratory neurons for control of breathing depth. Chemoresponsive pericolumnar tonic expiratory neurons, proposed to amplify inspiratory drive by disinhibition, were correlationally linked to afferent and efferent "chains" of chemoresponsive neurons extending to all monitored regions. The chains included coordinated clusters of chemoresponsive FTL-pF neurons with functional links to widespread medullary sites involved in the control of breathing. The results support long-standing concepts on brain stem network architecture and a circuit model for peripheral chemoreceptor modulation of breathing with multiple circuit loops and chains tuned by tegmental field neurons with quasi-periodic discharge patterns. NEW & NOTEWORTHY We tested the long-standing hypothesis that carotid chemoreceptors tune the frequency and depth of breathing through parallel circuit operations targeting the ventral respiratory column. Responses to stimulation of the chemoreceptors and identified functional connectivity support differential tuning of inspiratory neuron burst duration and firing rate and a model of brain stem network architecture incorporating tonic expiratory "hub" neurons regulated by convergent neuronal chains and loops through rostral lateral tegmental field neurons with quasi-periodic discharge patterns.

Thermal treatments to increase acoustic detectability of Sitophilus oryzae (Coleoptera: Curculionidae) in stored grain

Hidden infestations of stored-product insect larvae are detected most rapidly by acoustic techniques when the larvae are highly active. Larval activity is periodic, however, and it tends to decrease after the larvae are disturbed or cooled. Because of the practical need for rapid inspection of grain at commercial elevators, several heat treatments were tested as potential methods of increasing larval activity and improving the speed and reliability of acoustic detection under adverse conditions. Samples of grain infested with 4th instars of Sitophilus oryzae (L.) were exposed to different radiant and convective heat treatments after they had been conditioned at 11 degrees C, 17 degrees C, or room temperature for 12-24 h. Relative activity levels were evaluated over periods of 0-12 h based on the mean levels in a 15-min interval, 2 h after the beginning of a trial. In comparisons among treatments with precooled larvae, relative activity levels 5-10 min after brief heat pulses were 2-30 times higher than activity levels in precooled controls exposed only to ambient temperatures (25 degrees C). After 15-25 min, the relative activity levels of these heated larvae remained 2-5 times higher than those of the ambient controls. Brief movement disturbances inhibited activity for approximately 20 min at any temperature. These results suggest that, in general, larval detectability is enhanced if cool grain samples are warmed and all samples are left undisturbed for 15-20 min before inspection.

Broadcasts of wing-fanning vibrations recorded from calling male Ceratitis capitata (Diptera: Tephritidae) increase captures of females in traps

Female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), from the sterile-male rearing facility in El Pino, Guatemala, were exposed to broadcasts of wing-fanning vibrations recorded from males engaged in calling behavior to investigate the feasibility of developing a female-selective acoustic trap. The recorded signals had frequent amplitude fluctuations and peak frequencies approximately 350 Hz, typical of signals observed in previous studies of Mediterranean fruit fly acoustic behavior. Females did not exhibit long-distance phonotaxis, but remained near a speaker significantly longer when the sounds were broadcast at 103-107 dB than when the speaker was silent. In addition, significantly higher percentages of females were captured by yellow adhesive traps next to a broadcasting speaker than by traps next to a silent mimic. Additional bioassays were conducted with synthetic, 350-Hz tones produced by a thermoacoustic tube as well as with silent mimics of the different sound sources to examine the relative responsiveness of female Mediterranean fruit flies to traps with different acoustic and visual features. The visual attributes of the different sound source assemblies significantly affected capture rates. The range over which the broadcast significantly increased the percentage of female captures was <0.5 m, which may limit the utility of these acoustic cues in large-scale trapping programs. However, the findings of this study do justify further testing of whether optimized short-range acoustic signals could be used to augment longer range pheromonal and visual cues to improve the efficacy of female-selective traps.

Laboratory evaluation of an improved electronic grain probe insect counter

An Electronic Grain Probe Insect Counter system, which incorporates modified passive grain probes, allows offsite monitoring and detection of insect pests in stored grain. An electronic count is generated whenever an insect falls through an infrared beam in the sensor head located at the bottom of the electronic grain probe. We report descriptions and laboratory evaluations of prototype electronic grain probes that were custom-made in-house (n=8) and by small-scale manufacturing (n=54). Laboratory tests, in which dead insects were dropped through a probe, were conducted to determine if electronic probes accurately count the numbers of insects that are captured. Accuracy of the manufactured electronic probes increased as the size of the test insect increased from 93.6% for the smallest insect tested (Cryptolestes ferrugineus, the rusty grain beetle) to 99.5% for the largest (Tribolium castaneum, the red flour beetle). Custom-made probes were significantly more accurate for C. ferrugineus (96.5% versus 93.6%) but there was no difference in accuracies for the larger insects. Comparisons among all probes found that probe accuracy was correlated with variation in the magnitude of the output signal from the infrared phototransistor. Thus, use of diode/phototransistor pairs with a more consistent beam or with improved beam focus may further improve probe accuracy. Good performance was obtained with the manufactured electronic probes. Tests with live insects under field conditions are needed to further evaluate the system performance.

Insect infestation of stored oats in Florida and field evaluation of a device for counting insects electronically

Automated methods of monitoring stored grain for insect pests will contribute to early detection and aid in management of pest problems. An insect population infesting stored oats at a seed processing plant in north-central Florida was studied to test a device for counting insects electronically (Electronic Grain Probe Insect Counter, EGPIC), and to characterize the storage environment. The device counts insects as they fall through an infrared beam incorporated into a modified grain probe (pitfall) trap and transmits the counts to a computer for accumulation and storage. Eight traps were inserted into the surface of the grain bulk, and the insects trapped were identified and counted manually at weekly intervals. Grain temperature and moisture content also were recorded for each trap location. Manual and automatic counts were compared to estimate error in the EGPIC system. Both over- and undercounting occurred, and errors ranged from -79.4 to 82.4%. The mean absolute value of error (+/- SE) was 31.7% (+/- 4.3). At least 31 species, or higher taxa, were detected, but the psocid Liposcelis entomophila (Enderlein) and the foreign grain beetle, Ahasverus advena (Waltl), accounted for 88% of the captured insects. Species diversity, phenology, and spatial distribution are presented, as well as temporal and spatial distribution of grain temperature and moisture content. The data sets generated will find application in population modeling and development of integrated pest management systems for stored grain.

Hypoxia evokes a sequence of raphe-pontomedullary network operations for inspiratory drive amplification and gasping

Hypoxia can trigger a sequence of breathing-related behaviors, from tachypnea to apneusis to apnea and gasping, an autoresuscitative behavior that, via large tidal volumes and altered intrathoracic pressure, can enhance coronary perfusion, carotid blood flow, and sympathetic activity, and thereby coordinate cardiac and respiratory functions. We tested the hypothesis that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and a distributed efference copy mechanism that generates coordinated gasp-like discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from 6 decerebrate, vagotomized, neuromuscularly-blocked, and artificially ventilated adult cats. Arterial blood pressure, phrenic nerve activity, end-tidal CO2, and other parameters were monitored. Hypoxia was produced by ventilation with a gas mixture of 5% O2 in nitrogen (N2). Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-time scale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during tachypnea, apneusis and augmented bursts, apnea, and gasping. The functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated step increments in blood pressure reported here support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping that begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea.

Hypoxia evokes a sequence of raphe-pontomedullary network operations for inspiratory drive amplification and gasping

Hypoxia can trigger a sequence of breathing-related behaviors, from augmentation to apneusis to apnea and gasping. Gasping is an autoresuscitative behavior that, via large tidal volumes and altered intrathoracic pressure, can enhance coronary perfusion, carotid blood flow, and sympathetic activity, and thereby coordinate cardiac and respiratory functions. We tested the hypotheses that hypoxia-evoked gasps are amplified through a disinhibitory microcircuit within the inspiratory neuron chain and that this drive is distributed via an efference copy mechanism. This generates coordinated gasplike discharges concurrently in other circuits of the raphe-pontomedullary respiratory network. Data were obtained from six decerebrate, vagotomized, neuromuscularly blocked, and artificially ventilated adult cats. Arterial blood pressure, phrenic nerve activity, end-tidal CO2, and other parameters were monitored. Hypoxia was produced by ventilation with a gas mixture of 5% O2 in nitrogen. Neuron spike trains were recorded at multiple pontomedullary sites simultaneously and evaluated for firing rate modulations and short-timescale correlations indicative of functional connectivity. Experimental perturbations evoked reconfiguration of raphe-pontomedullary circuits during initial augmentation, apneusis and augmented bursts, apnea, and gasping. Functional connectivity, altered firing rates, efference copy of gasp drive, and coordinated incremental blood pressure increases support a distributed brain stem network model for amplification and broadcasting of inspiratory drive during autoresuscitative gasping. Gasping begins with a reduction in inhibition by expiratory neurons and an initial loss of inspiratory drive during hypoxic apnea and culminates in autoresuscitative efforts. NEW & NOTEWORTHY Severe hypoxia evokes a sequence of breathing-related behaviors culminating in gasping. We report firing rate modulations and short-timescale correlations in spike trains recorded simultaneously in the raphe-pontomedullary respiratory network during hypoxia. Our findings support a disinhibitory microcircuit and a distributed efference copy mechanism for amplification of gasping. Coordinated increments in blood pressure lead to a model for autoresuscitative bootstrapping of peripheral chemoreceptor reflexes, breathing, and sympathetic activity, complementing and extending prior work.

Behavioral management instruction of anxious clients in the dental hygiene curricula

PURPOSE

This study sought to determine the type and amount of instruction on behavioral management of anxious clients in dental hygiene curricula, the instructional differences between associate and baccalaureate programs, and the opinions of educators regarding behavioral management.

METHODS

A 19-item questionnaire was mailed to the directors of 210 dental hygiene programs who were asked to furnish information pertaining to behavioral instruction in their curricula and to express their opinions by use of a Likert scale. Data were analyzed using descriptive statistics and the chi-square and Z hypothesis tests.

RESULTS

Two mailings resulted in an overall response rate of 81%, with 170 questionnaires returned. Results revealed that 86% of programs surveyed taught behavioral management of anxious clients to their students. Types of strategies taught and percentage of programs teaching them were: information provision (96%), distraction (51%), modeling (51%), relaxation (62%), and hypnosis (7%). No significant relationships were found between associate and baccalaureate degree programs relating to the type of behavioral instruction; however, baccalaureate degree programs devoted significantly more curricular hours to this instruction. In general, the sample of dental hygiene educators held positive opinions regarding the use of behavioral management, with only 28% having had formal education in this area.

CONCLUSION

Results suggest that comprehensive instruction on behavioral management of client anxiety is not provided to students in all dental hygiene programs, even though dental hygiene educators consider this modality effective during oral health care.

ADHA Graduate Student/Faculty Research Project: health history

PURPOSE

An American Dental Hygienists' Association (ADHA) study gathered demographic and practice data on dental hygienists in the United States. This paper describes the health history component of the survey. Specifically, this report focuses on who sees new patients first in the dental office, who collects health history information, who updates the health history and when, type of health history used, and how positive responses to health history items are investigated.

METHODS

A questionnaire jointly developed by ADHA and a research firm was sent in July 1986 to a stratified random sample of 10,507 ADHA member and nonmember dental hygienists licensed and practicing in the United States. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) to determine frequency distributions, cross-tabulations, and select profiles. Results. A response rate of 49.6% was obtained. Results revealed that new nonemergency patients were scheduled first with the dental hygienist. Health histories were recorded for almost all new patients but updated irregularly. A combination of a self-administered form and verbal interview was used. Recall patients' health histories were mainly updated by an oral interview. Follow-up on positive responses was most often accomplished by asking additional questions, followed by consultation with the dentist and/or physician. Dental hygienists felt least adequately informed to follow up on positive responses to homosexual status, and i.v. and recreational drug use. Conclusions. The dental hygienist plays a significant role in health history data collection both for new and recall patients. Educational programs for entry-level and practicing dental hygienists should emphasize effective interviewing to gather patient health history data.

A model for integrating student and faculty research

Research productivity is a major criterion for measuring academic performance in most universities today. Because of heavy teaching loads, dental hygiene faculty often have difficulty allocating adequate time to conduct research. Thus, professional advancement might be impeded since faculty may be less productive in the research area than is desired by the academic unit. A method that might assist dental hygiene faculty to become more research productive focuses on student involvement with faculty on collaborative research projects. The purpose of this article is to describe a model designed to enhance the integration of faculty and student research in dental hygiene and to explain the benefits inherent in dental hygiene student involvement with faculty on collaborative research projects.

Attitudes of dental hygienists toward continuing education

The purpose of this study was to assess attitudes of dental hygienists toward continuing education (CE) in two states: Kentucky, a state with mandatory continuing education (MCE), and Virginia, a state without MCE. A self-designed, 13-item, attitudinal questionnaire was sent to a random sample of licensed hygienists in Kentucky and Virginia. Of the 400 hygienists surveyed (200 in Virginia and 200 in Kentucky), 246 questionnaires were returned for an overall response rate of 61.5%. Data analyses reveal that the majority of respondents from Kentucky and Virginia believe that dental hygienists have a professional obligation to improve their knowledge and skills through participation in continuing education, and that participation in CE contributes to personal self-esteem and confidence. However, the behavior of Virginia respondents seems to be in conflict with their attitudes, since the majority of Virginia respondents on the average had earned an extremely small number of CEUs in the last two years compared to the majority of Kentucky respondents who had earned a large number of CEUs. Generally, Kentucky dental hygienists responded more often in the affirmative than Virginia respondents regarding CE, particularly in areas of mandatory continuing education and benefits of CE. Results of this study indicate that mandated CE does not negatively influence attitudes of dental hygienists toward CE, since Kentucky respondents had more positive attitudes toward CE while Virginia respondents had less positive or more unformed attitudes toward CE. Therefore, increased exposure to CE through MCE may result in more favorable attitudes of dental hygienists toward continuing education.

AIDS education in dental hygiene programs in the United States and Canada

The purpose of this study was to determine school policies, acquired immunodeficiency syndrome (AIDS) -related content areas, and curricula hours devoted to AIDS study in accredited schools of dental hygiene. The sample included all 217 accredited programs in the United States and Canada. Eighty-five percent (184) of the sample completed the 10-item questionnaire. Results reveal that 98% of the respondents include information on the oral disease manifestations of AIDS in their curricula. Over 70% of the sample include material on AIDS etiology, incidence, epidemiology, general clinical symptoms, HIV testing, attitudes and fears of practitioners, and dental hygiene care and treatment. Most schools spend four to 10 curricula hours covering general content on AIDS. Over one-half of the respondents require students to use special infection control protocols. When treating known infectious disease patients. Most schools responding have policies which favor student treatment of HIV-positive patients, and the majority of the respondents do not have a written policy concerning admitting students who are HIV-positive. Less than 30% of the schools teach financing of AIDS-related healthcare or AIDS resources. One respondent admitted not including any AIDS information in the curricula. Results suggest that most accredited schools of dental hygiene in the United States and Canada should include additional information on AIDS in their curricula to ensure student competency in providing oral healthcare to HIV-infected individuals.

Modeling Insights into Potential Mechanisms of Opioid-Induced Respiratory Depression within Medullary and Pontine Networks

The opioid epidemic is a pervasive health issue and continues to have a drastic impact on the United States. This is primarily because opioids cause respiratory suppression and the leading cause of death in opioid overdose is respiratory failure (i.e., opioid-induced respiratory depression, OIRD). Opioid administration can affect the frequency and magnitude of inspiratory motor drive by activating μ-opioid receptors that are located throughout the respiratory control network in the brainstem. This can significantly affect ventilation and blunt CO2 responsiveness, but the precise neural mechanisms that suppress breathing are not fully understood. Previous research has suggested that opioids affect medullary and pontine inspiratory neuron activity by disrupting upstream elements within this circuit. Inspiratory neurons within this network exhibit synchrony consistent with shared excitation from other neuron populations and recurrent mechanisms. One possible target for opioid suppression of inspiratory drive are excitatory synapses. Reduced excitability of these synaptic elements may result in disfacilitation and reduced synchrony among inspiratory neurons. Downstream effects of disfacilitation may result in abnormal output from phrenic motoneurons resulting in distressed breathing. We tested the plausibility of this hypothesis with a computational model of the respiratory network by targeting the synaptic excitability in fictive medullary and pontine populations. The synaptic conductances were systematically decreased while monitoring the overall respiratory motor pattern and aggregate firing rates of subsets of cell populations. Simulations suggest that highly selective, rather than generalized, actions of opioids on synapses within the inspiratory network may account for different observed breathing mechanics.