CONTACT DERMATITIS, Issue 1 2001
Jun Young Lee
The high risk of occupational contact dermatitis in dental personnel are well accepted throughout the world. There are few reports concerning occupational skin disease in dental personnel in Korea. The purposes of this study were to investigate the frequency, characteristics and causative factors of contact dermatitis in Korean dental technicians. Recording of personal history, physical examination and patch tests with the Korean standard series and dental screening series were performed in 49 dental technicians. Most of the subjects were exposed to a variety of compounds, including acrylics, metals, plaster, alginate, etc. 22 (44.9%) subjects had contact dermatitis, present or past, and the site involved was the hand in all 22. The most common clinical feature of hand dermatitis was itching (77.3%); scaling, fissuring and erythema were other common clinical features. Metals, including potassium dichromate (24.5%), nickel sulfate (18.4%), mercury ammonium chloride (16.3%), cobalt chloride (12.2%) and palladium chloride (10.2%), showed high positive rates in patch test results of 49 dental technicians. 7 positive reactions to the various acrylics were found in 3 subjects. In our study, the frequency and clinical features of the contact dermatitis showed a similarity to other reports, though the patch test results were somewhat different; a higher patch-positive reaction to metals and a relatively lower patch-positive reaction to acrylics than the patch test results reported in Europe. [source]

Interobserver Reliability of Video Recording in the Diagnosis of Nocturnal Frontal Lobe Seizures

EPILEPSIA, Issue 8 2007
Luca Vignatelli
Summary:,Background: Nocturnal frontal lobe seizures (NFLS) show one or all of the following semeiological patterns: (1) paroxysmal arousals (PA: brief and sudden recurrent motor paroxysmal behavior); (2) hyperkinetic seizures (HS: motor attacks with complex dyskinetic features); (3) asymmetric bilateral tonic seizures (ATS: motor attacks with dystonic features); (4) epileptic nocturnal wanderings (ENW: stereotyped, prolonged ambulatory behavior). Objective: To estimate the interobserver reliability (IR) of video-recording diagnosis in patients with suspected NFLS among sleep medicine experts, epileptologists, and trainees in sleep medicine. Methods: Sixty-six patients with suspected NFLS were included. All underwent nocturnal video-polysomnographic recording. Six doctors (three experts and three trainees) independently classified each case as "NFLS ascertained" (according to the above specified subtypes: PA, HS, ATS, ENW) or "NFLS excluded". IR was calculated by means of Kappa statistics, and interpreted according to the standard classification (0.0,0.20 = slight agreement; 0.21,0.40 = fair; 0.41,0.60 = moderate; 0.61,0.80 = substantial; 0.81,1.00 = almost perfect). Results: The observed raw agreement ranged from 63% to 79% between each pair of raters; the IR ranged from "moderate" (kappa = 0.50) to "substantial" (kappa = 0.72). A major source of variance was the disagreement in distinguishing between PA and nonepileptic arousals, without differences in the level of agreement between experts and trainees. Conclusions: Among sleep experts and trainees, IR of diagnosis of NFLS, based on videotaped observation of sleep phenomena, is not satisfactory. Explicit video-polysomnographic criteria for the classification of paroxysmal sleep motor phenomena are needed. [source]

Adding Video Recording Increases the Diagnostic Yield of Routine Electroencephalograms in Children with Frequent Paroxysmal Events

EPILEPSIA, Issue 5 2005
Nathan Watemberg
Summary:,Purpose: To report on the usefulness of adding video recording to routine EEG studies of infants and children with frequent paroxysmal events. Methods: We analyzed the efficacy of this diagnostic means during a 4-year period. The decision whether to add video recording was made by the pediatric EEG interpreter at the time of the study. Studies were planned to last between 20 and 30 min, and, if needed, were extended by the EEG interpreter. For most studies, video recording was added from the beginning of EEG recording. In a minority of cases, the addition of video was implemented during the first part of the EEG test, as clinical events became obvious. In these cases, a new study (file) was begun. The success rate was analyzed according to the indications for the EEG study: paroxysmal eye movements, tremor, suspected seizures, myoclonus, staring episodes, suspected stereotypias and tics, absence epilepsy follow-up, cyanotic episodes, and suspected psychogenic nonepileptic events. Results: Video recording was added to 137 of 666 routine studies. Mean patient age was 4.8 years. The nature of the event was determined in 61 (45%) of the EEG studies. Twenty-eight percent were hospitalized patients. The average study duration was 26 min. This diagnostic means was particularly useful for paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and psychogenic nonepileptic events. About 46% of 116 patients for whom cognitive data were available were mentally retarded. EEG with added video recording was successfully performed in all 116 cases and provided useful information in 29 (55%) of these 53 patients. Conclusions: Adding video recording to routine EEG was helpful in 45% of cases referred for frequent paroxysmal events. This technique proved useful for hospitalized children as well as for outpatients. Moreover, it was successfully applied in cognitively impaired patients. Infants and children with paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and pseudoseizures especially benefited from this diagnostic means. Because of its low cost and the little discomfort imposed on the patient and his or her family, this technique should be considered as a first diagnostic step in children with frequent paroxysmal events. [source]

Developmental changes in the BDNF-induced modulation of inhibitory synaptic transmission in the Kölliker,Fuse nucleus of rat

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007
Miriam Kron
Abstract The Kölliker,Fuse nucleus (KF), part of the pontine respiratory group, is involved in the control of respiratory phase duration, and receives both excitatory and inhibitory afferent input from various other brain regions. There is evidence for developmental changes in the modulation of excitatory inputs to the KF by the neurotrophin brain-derived neurotrophic factor (BDNF). In the present study we investigated if BDNF exerts developmental effects on inhibitory synaptic transmission in the KF. Recordings of inhibitory postsynaptic currents (IPSCs) in KF neurons in a pontine slice preparation revealed general developmental changes. Recording of spontaneous and evoked IPSCs (sIPSCs, eIPSCS) revealed that neonatally the ,-aminobutyric acid (GABA)ergic fraction of IPSCs was predominant, while in later developmental stages glycinergic neurotransmission significantly increased. Bath-application of BDNF significantly reduced sIPSC frequency in all developmental stages, while BDNF-mediated modulation on eIPSCs showed developmental differences. The eIPSCs mean amplitude was uniformly and significantly reduced following BDNF application only in neurons from rats younger than postnatal day 10. At later postnatal stages the response pattern became heterogeneous, and both augmentations and reductions of eIPSC amplitudes occurred. All BDNF effects on eIPSCs and sIPSCs were reversed with the tyrosine kinase receptor-B inhibitor K252a. We conclude that developmental changes in inhibitory neurotransmission, including the BDNF-mediated modulation of eIPSCs, relate to the postnatal maturation of the KF. The changes in BDNF-mediated modulation of IPSCs in the KF may have strong implications for developmental changes in synaptic plasticity and the adaptation of the breathing pattern to afferent inputs. [source]

Improving the ON/OFF Ratio and Reversibility of Recording by Rational Structural Arrangement of Donor,Acceptor Molecules

ADVANCED FUNCTIONAL MATERIALS, Issue 5 2010
Ying Ma
Abstract Organic molecules with donor,acceptor (D,A) structure are an important type of material for nanoelectronics and molecular electronics. The influence of the electron donor and acceptor units on the electrical function of materials is a worthy topic for the development of high-performance data storage. In this work, the effect of different D,A structures (namely D,,,A,,,D and A,,,D,,,A) on the electronic switching properties of triphenylamine-based molecules is investigated. Devices based on D,,,A,,,D molecules exhibit excellent write,read,erase characteristics with a high ON/OFF ratio of up to 106, while that based on A,,,D,,,A molecules exhibit irreversible switching behavior with an ON/OFF ratio of about (3.2,×,101),(1,×,103). Moreover, long retention time of the high conductance state and low threshold voltage are observed for the D,A switching materials. Accordingly, stable and reliable nanoscale data storage is achieved on the thin films of the D,A molecules by scanning tunneling microscopy. The influence of the arrangement of the D and A within the molecular backbone disclosed in this study will be of significance for improving the electronic switching properties (ON/OFF current ratio and reversibility) of new molecular systems, so as to achieve more efficient data storage through appropriate design strategies. [source]

Diamond Transistor Array for Extracellular Recording From Electrogenic Cells

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2009
Markus Dankerl
Abstract The transduction of electric signals from cells to electronic devices is mandatory for medical applications such as neuroprostheses and fundamental research on communication in neuronal networks. Here, the use of diamond with its advantages for biological applications as a new material for biohybrid devices for the detection of cell signals is investigated. Using the surface conductivity of hydrogen-terminated single-crystalline diamond substrates, arrays of solution-gate field-effect transistors were fabricated. The characterization of the transistors reveals a good stability in electrolyte solutions for at least 7 days. On these devices, cardiomyocyte-like HL-1 cells as well as human embryonic kidney cells (HEK293), which were stably transfected with potassium channels, are cultured. Both types of cells show healthy growth and good adhesion to the substrate. The diamond transistors are used to detect electrical signals from both types of cells by recording the extracellular potential. For the HL-1 cells, the shape of action potentials can be resolved and the propagation of the signal across the cell layer is visible. Potassium currents of HEK293 cells are activated with the patch-clamp technique in voltage-clamp mode and simultaneously measured with the field-effect transistors. The ion sensitivity of the diamond surface enables the detection of released potassium ions accumulated in the cleft between transistor and cell. [source]

Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994,2004) at the GLORIA, master site Schrankogel, Tyrol, Austria

GLOBAL CHANGE BIOLOGY, Issue 1 2007
HARALD PAULI
Abstract High mountain ecosystems are defined by low temperatures and are therefore considered to react sensitively to climate warming. Responding to observed changes in plant species richness on high peaks of the European Alps, an extensive setup of 1 m × 1 m permanent plots was established at the alpine-nival ecotone (between 2900 and 3450 m) on Mount Schrankogel, a GLORIA master site in the central Tyrolean Alps, Austria, in 1994. Recording was repeated in a representative selection of 362 quadrats in 2004. Ten years after the first recording, we observed an average change in vascular plant species richness from 11.4 to 12.7 species per plot, an increase of 11.8% (or of at least 10.6% at a 95% confidence level). The increase in species richness involved 23 species (about 43% of all taxa found at the ecotone), comprising both alpine and nival species and was pronouncedly higher in plots with subnival/nival vegetation than in plots with alpine grassland vegetation. Only three species showed a decrease in plot occupancy: one was an annual species, one was rare, and one a common nival plant that decreased in one part of the area but increased in the uppermost part. Species cover changed in relation to altitudinal preferences of species, showing significant declines of all subnival to nival plants, whereas alpine pioneer species increased in cover. Recent climate warming in the Alps, which has been twice as high as the global average, is considered to be the primary driver of the observed differential changes in species cover. Our results indicate an ongoing range contraction of subnival to nival species at their rear (i.e. lower) edge and a concurrent expansion of alpine pioneer species at their leading edge. Although this was expected from predictive distribution models and different temperature-related habitat preferences of alpine and nival species, we provide first evidence on , most likely , warming-induced species declines in the high European Alps. The projected acceleration of climate warming raises concerns that this phenomenon could become the major threat to biodiversity in high mountains. [source]

Cover Picture: TiO2 Nanoparticle,Photopolymer Composites for Volume Holographic Recording (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2005
Mater.
Abstract TiO2 nanoparticle,photopolymer composites have been employed for volume holographic recording, as reported by Sánchez and co-workers on p.,1623. Photoinduced segregation of the high refractive index, grafted nanoparticles between polymer-rich areas leads to improved refractive-index modulation amplitudes with respect to the base material without nanoparticles. The cover schematically shows a holographic grating registered in this nanocomposite material. These nanocomposite materials should enable the production of holographic optical elements to efficiently control light with angle and wavelength selectivity. This could be used, for example, in liquid-crystal display technology. A new and efficient photopolymer for the recording of volume holograms is presented. The material comprises a mixture of UV-sensitive acrylates and grafted titanium dioxide nanoparticles with an average size of 4,nm. We report the formation of holographic gratings with refractive-index modulation amplitudes of up to 15.5,×,10,3,an improvement of more than a factor of four over the base material without nanoparticles,while maintaining a low level of scattering and a high transparency in the visible-wavelength range. The influence of the composition of the acrylate system on the final properties of the holographic material is also investigated and discussed. The presence of multifunctional monomers favors the compositional segregation of the different components, while the addition of monofunctional acrylate, highly compatible with the grafting of the nanoparticles, favors the dilution of these nanoparticles. [source]

Contrasting roles of neural firing rate and local field potentials in human memory

HIPPOCAMPUS, Issue 8 2007
Arne Ekstrom
Abstract Recording the activity of neurons is a mainstay of animal memory research, while human recordings are generally limited to the activity of large ensembles of cells. The relationship between ensemble activity and neural firing rate during declarative memory processes, however, remains unclear. We recorded neurons and local field potentials (LFPs) simultaneously from the same sites in the human hippocampus and entorhinal cortex (ERC) in patients with implanted intracranial electrodes during a virtual taxi-driver task that also included a memory retrieval component. Neurons increased their firing rate in response to specific passengers or landmarks both during navigation and retrieval. Although we did not find item specificity in the broadband LFP, both ,- and ,-band LFPs increased power to specific items on a small but significant percent of channels. These responses, however, did not correlate with item-specific neural responses. To contrast item-specific responses with process-specific responses during memory, we compared neural and LFP responses during encoding (navigation) and retrieval (associative and item-specific recognition). A subset of neurons also altered firing rates nonspecifically while subjects viewed items during encoding. Interestingly, LFPs in the hippocampus and ERC increased in power nonspecifically while subjects viewed items during retrieval, more often during associative than item-recognition. Furthermore, we found no correlation between neural firing rate and broadband, ,-band, and ,-band LFPs during process-specific responses. Our findings suggest that neuronal firing and ensemble activity can be dissociated during encoding, item-maintenance, and retrieval in the human hippocampal area, likely relating to functional properties unique to this region. © 2007 Wiley-Liss, Inc. [source]

Neural Electrodes: Interfacing Conducting Polymer Nanotubes with the Central Nervous System: Chronic Neural Recording using Poly(3,4-ethylenedioxythiophene) Nanotubes (Adv. Mater.

ADVANCED MATERIALS, Issue 37 2009
37/2009)
Microelectrodes implanted in the brain are increasingly being used to treat neurological disorders. However, robust and reliable chronic application of neural electrodes remains a challenge. Mohammed Reza Abidian and co-workers report on p. 3764 the use of conducting polymer nanotubes as highly selective neural interfaces for chronic neural recordings at the microscale. The quality of neuronal spike recordings was significantly improved relative to comparably sized metal electrode sites, primarily through a reduced noise level amidst maintained spike amplitudes. [source]

Interfacing Conducting Polymer Nanotubes with the Central Nervous System: Chronic Neural Recording using Poly(3,4-ethylenedioxythiophene) Nanotubes

ADVANCED MATERIALS, Issue 37 2009
Mohammad Reza Abidian
Microelectrodes implanted in the brain are increasingly being used to treat neurological disorders. However, robust and reliable chronic application of neural electrodes remains a challenge. Here, we report, the use of conducting polymer nanotubes as highly selective neural interfaces for chronic neural recordings. Poly(3,4-ethylenedioxythiophene) nanotubes were formed on the chronic neural microelectrode. The quality of neuronal spike recordings was significantly improved relative to metal electrode sites. [source]

Intracanal temperature rise evaluation during the usage of the System B: replication of intracanal anatomy

INTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2005
J. C. Villegas
Abstract Aim To evaluate and determine intracanal temperature rises at 2 and 4 mm from the working length (WL) necessary to obtain proper replication of intracanal anatomy with gutta-percha (GP) using the System B heat source during vertical condensation. Methodology A split-tooth model was prepared and artificial shallow depressions were cut in the buccal canal wall 2 and 4 mm from the WL. At the same level on the palatal wall holes were drilled to adapt two thermocouples. The canal was filled using GP in a vertical condensation technique by placing the System B plugger at 2 and 4 mm from the WL in groups A and B, respectively. Two control groups in which no GP was used were carried out placing the plugger 2 and 4 mm from the WL (groups A.c and B.c, respectively) and activating the heat source. Recording of temperature rise was carried out during the filling procedure for groups A and B and during activation for control groups A.c and B.c; the highest temperatures were recorded. After each filling was completed, 3 min were allowed for the GP to cool and the model divided to reveal the filling. Images of the GP were taken with a CCD camera to evaluate the presence of replication of artificial round depressions. In control groups, the temperature was recorded for 20 s after a 3 s activation of the heat source. The rise in temperature was compared between the groups individually at each level (2 or 4 mm) and statistically analysed using one-way anova and Fisher PLSD tests at 5% of significance level (P < 0.05). Results Mean temperature rises of 14 ± 3 and 12 ± 2 °C at 2 and 4 mm from the WL, respectively, were observed in group A fillings, and 4 ± 1 and 6 ± 1 °C at 2 and 4 mm, respectively, in group B fillings. Recordings at 2 mm showed significantly (P < 0.05) higher temperature rises with group A.c when compared with groups B and B.c. Replication of intracanal anatomy with GP was always found in group A fillings at both levels but only 4 mm from the WL in group B fillings. Conclusions Positioning the plugger close to WL and a temperature rise of 6 °C were necessary to obtain replication of intracanal anatomy. A mean temperature rise of 4 °C at 2 mm from WL (group B) resulted in no replication of intracanal anatomy. Further studies simulating clinical conditions are necessary. [source]

Reversible Photoregulation of the Electrical Conductivity of Spiropyran-Doped Polyaniline for Information Recording and Nondestructive Processing ,

ADVANCED MATERIALS, Issue 7 2004
X. Guo
Reversibly photoswitchable proton transfer processes can occur between a three-state molecular switch based on spiropyran (SP) and the "salt form" of polyaniline (see Figure), both in solution and in the solid state. As a result, the electrical conductivity of the thin-film of SP-doped polyaniline can be photoregulated. [source]

Nursing and medical staff knowledge regarding the monitoring and management of accidental or exposure hypothermia in adult major trauma patients

INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 6 2006
Sharyn Ireland RN Dip.HSc B.Nurs CritCareCert ACCN M.Ed
Recording a patient's vital signs is a basic requirement that in part informs clinical decision-making. Practice suggests that recording a trauma patient's temperature is occasionally overlooked in the emergency department. A staff survey was undertaken to gain an appreciation of knowledge and understanding of the issues that surround accidental or exposure hypothermia in trauma patients. Results demonstrate that nurses and doctors are unsure of how to define hypothermia and are not conversant with simple ways to prevent heat loss or rewarm patients. Complications from hypothermia such as coagulopathy and metabolic acidosis were seldom identified. Issues that limit staff recording temperature include patient access and acuity, lack of knowledge and confidence and access to temperature-measuring devices. These results emphasize the need for regular education. Implications for clinical practice were considered; an algorithm to guide staff on ways to improve the monitoring and management of temperature in trauma patients was developed. Opportunities for ongoing and further research were identified. [source]

Pharmacists' role in smoking cessation: an examination of current practice and barriers to service provision

INTERNATIONAL JOURNAL OF PHARMACY PRACTICE, Issue 4 2006
David Edwards PhD student
Objective This study addressed the potential role of pharmacists in helping their patients to quit smoking by providing a summary of their self-reported levels of current activities, confidence, and readiness to change around the provision of brief advice and support for patients who smoke. In addition to investigating which barriers are perceived to be most important, this study also examined the relative importance of confidence, barriers and practice factors in relation to pharmacists' smoking cessation practices. Method A 58-item questionnaire was mailed to 720 pharmacists. The questionnaire measured demographic and background variables, level of smoking cessation activity (asking, advising, assessing, assisting and arranging including follow-up), confidence in undertaking smoking-cessation activities, readiness to change, perceived importance of barriers to providing smoking-cessation services, and further education or training in relation to smoking cessation. Setting Community pharmacists in South Australia. Key findings Respondents indicated high rates of activity in relation to assessing and assisting patients to quit smoking, with lower rates of advising and arranging including following up. Recording of smoking status was very low. Confidence emerged as the most important predictor of smoking-cessation activities, with pharmacist barriers including fear of alienating patients approaching significance. Reported levels of smoking-specific education and training were low. Conclusions South Australian pharmacists are contributing to the prevention of tobacco-related harms. With additional support there is a greater scope for involvement. Results indicate a need for a team-based, systematic and multifaceted approach to address barriers and enhance pharmacists' confidence. Further implementation research is required to assess the effectiveness of multifaceted pharmacy support programmes on the uptake and sustainability of smoking-cessation services. [source]

The influence of citalopram on interdigestive gastrointestinal motility in man

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2010
P. Janssen
Aliment Pharmacol Ther 2010; 32: 289,295 Summary Background, Administration of 5-hydroxytryptamine (5HT) and selective 5HT receptor ligands modifies interdigestive motility in animals and in man. Aim, To study the effect of citalopram, a selective 5-HT reuptake inhibitor, on interdigestive motility in man. Methods, In 20 healthy subjects, antroduodenojejunal motor activity was studied manometrically. Basal interdigestive motor activity was recorded until the passage of two activity fronts. Ten minutes after the second activity front, placebo or 20 mg of citalopram was administered intravenously in a double-blind randomized fashion. Recording continued until the passage of two more activity fronts had occurred. Results, Administration of citalopram induced a premature small intestinal phase 3 after 35 ± 6.4 min, compared to 120 ± 17 min after placebo P < 0.01. Citalopram shortened MMC cycle length at the expense of phase 1 and phase 2 and significantly increased the motility index during phase 2 in the antrum and the small intestine. Conclusions, In the interdigestive state in man, intravenous administration of the selective 5-HT reuptake inhibitor citalopram induces a premature intestinal phase 3 and suppresses gastric activity fronts. Phase 2 motility is stimulated both in the stomach and in the small bowel after citalopram. These data suggest that 5HT is involved in the control of interdigestive motility. [source]

Validation of 2 Techniques for Electrocardiographic Recording in Dogs and Cats

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2006
Luca Ferasin
Background: Standard electrocardiographic (ECG) recording in the dog and cat is commonly performed in right lateral recumbency, by connecting the ECG leads to the skin of the patient via metallic alligator clips. The jaws of the alligator clips are usually filed or flattened to reduce their uncomfortable pressure on the patient's skin. However, filed and flattened alligator clips can occasionally lose their grip to the skin, causing lead detachment during standard ECG recording. Hypothesis: The aim of the study was to validate two novel ECG recording techniques ("gel" and "pads"). Animals: Six-lead standard ECG recording was obtained from 42 dogs and 40 cats using the standard technique, as well as the two novel methods. Methods: Measurements were taken of the amplitude and duration of P waves and QRS complexes, duration of PQ and QT intervals, and mean electrical axis (MEA). In each recording, five representative complexes were measured, and the results were averaged for each parameter. Results: A good quality ECG recording was obtained with all the three different techniques, although a degree of wandering trace was observed in one third of cats with the "pads" technique. Bland-Altman analysis showed good agreement between the ECG values recorded with the two novel techniques and those recorded with the standard traditional technique. Furthermore, the observed differences were not clinically relevant, except for the R wave amplitude recorded with the "pads" method in cats (-0.35 to 0.37 mV). Conclusions and Clinical Importance: In conclusion, this study supports the reliability and clinical validity of the "gel" and "pads" techniques for ECG recording both in the dog and the cat, with some limitations for the "pads" technique in cats. [source]

Guidelines for Collecting and Recording the Race and Ethnicity of Juveniles in Conjunction with Juvenile Delinquency Disposition Reporting to the Juvenile Court Judges' Commission

JUVENILE AND FAMILY COURT JOURNAL, Issue 2 2007
PATRICIA TORBET
ABSTRACT One of the most compelling reasons for accurate racial coding of juveniles involved in the juvenile justice system is to ensure that all youth are treated fairly, regardless of race or ethnicity. Pennsylvania juvenile courts and probation departments now have instructions and guidelines for collecting and recording race and ethnicity in compliance with Federal standards. These guidelines can be easily adopted by other states and jurisdictions. [source]

Blood Flow in Snake Infrared Organs: Response-Induced Changes in Individual Vessels

MICROCIRCULATION, Issue 2 2007
RICHARD C. GORIS
ABSTRACT Objective: In the past the microkinetics of blood flow in the infrared pit organs of pit vipers has been studied with Doppler flowmetry using various infrared stimuli such as a human hand or soldering iron at various distances, lasers of various wavelengths, etc. Quick-acting variations in blood flow were recorded, and interpreted as a cooling mechanism for avoiding afterimage in the infrared receptors. However, the Doppler measurements provided only the summation of blood flow in a number of vessels covered by the sensing probe, but did not give data on flow in individual vessels. Methods: In the present work the authors introduced into the bloodstream of Gloydius and Trimeresurus pit vipers fluorescent microspheres labeled with fluorescein isothiocyanate (FITC) contained in a solution of FITC-dextran in physiological saline. They observed the passage of the microspheres through individual pit organ vessels with a fluorescent microscope to which was attached a high-speed video camera and image intensifier. Output of the camera was recorded before, during, and after stimulus with a 810-nm diode laser. Recording was done at 250 frames/s on high-speed video apparatus and downloaded to a hard disk. Disk files were loaded into proprietary software and particles were tracked and average velocities calculated. The data were then tested for significance by ANOVA with post hoc tests. Results: A significant (p < .05) increase in blood velocity was found at the focal point of the stimulus laser, but not anywhere removed from this point. Proximal severing of the pit sensory nerves caused degeneration of the pit receptor terminals and abolished stimulus-induced blood flow changes, but did not affect normal blood flow. Conclusions: The authors conclude that the receptors themselves are directly and locally controlling the smooth muscle elements of the blood vessels, in response to heating of the receptors by infrared radiation. They speculate that the heavy vascularization constitutes a cooling system for the radiation-encoding receptors, and further that the agent of control may be a volatile neuromediator such as nitric oxide. [source]

Marxism, Urban Geography and Classical Recording: An Alternative to Cultural Studies

MUSIC ANALYSIS, Issue 3 2001
Adam Krims
[source]

Multiple-Cell Spike Density and Neural Noise Level Analysis by Semimicroelectrode Recording for Identification of the Subthalamic Nucleus During Surgery for Parkinson's Disease

NEUROMODULATION, Issue 1 2008
Toshikazu Kano MD
ABSTRACT Objective.,, For targeting the subthalamic nucleus (STN), we attempted to quantify the changes in multiple cell activities by computing the neural noise level and multiple-cell spike density (MSD). Methods.,, We analyzed the neural noise level and MSD by stepwise recording at every 0.25-mm increment during the final tracking in 90 sides of 45 patients with Parkinson's disease. The MSD was analyzed with cut-off levels ranging from 1.2- to 2.0-fold the neural noise level in the internal capsule or zona incerta in each trajectory. Results.,, The dorsal boundary of the STN was identified from an increase in the neural noise ratio in all sides. The ventral boundary was identifiable, however, from a decrease in the neural noise ratio in only 70 sides (78%). In contrast, both the dorsal and ventral boundaries were clearly identified from an increase and a decrease in the MSD, respectively, in all of the 90 sides. Conclusion.,, MSD analysis by semimicroelectrode recording represents a useful, practical, and apparently reliable means for identifying the boundaries of the STN. [source]

Relevance Of Multi-channel Microelectrode Recording in Deep Brain Stimulation of the Subthalamic Nucleus (STN) in Parkinson's Disease

NEUROMODULATION, Issue 3 2003
Servello A
[source]

Diffractive imaging for periodic samples: retrieving one-dimensional concentration profiles across microfluidic channels

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2007
Oliver Bunk
A technique has been developed that allows determination of the concentration profiles of colloidal solutions or any kind of fluid under confinement. Currently, submicrometre-wide channels are sampled with a resolution in the 10,nm range. The method comprises regular arrays of microfluidic channels and one-dimensional X-ray phase-retrieval techniques for the analysis of small-angle X-ray diffraction from the array structures. Recording the X-ray diffraction data requires a low dose on each individual channel since the sum of the signals from all channels is detected. The determined concentration profiles represent the ensemble average rather than individual entities and are obtained in a model-independent way. As an example, amplitude and phase of the exit field and concentration profiles for a colloidal fluid within confining channels of different widths are shown. [source]

Morpho-physical Recording of Bovine Conceptus (Bos indicus) and Placenta from Days 20 to 70 of Pregnancy

REPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2010
AC Assis Neto
Contents The study is based on 141 pregnant Bos indicus cows, from days 20 to 70 post-insemination. First, special attention was given to the macroscopically observable phenomena of attachment of the conceptus to the uterus, i.e. the implantation, from about days 20 to 30 post-insemination up to day 70, and placentome development by growth, vascularization and increase in the number of cotyledons opposite to the endometrial caruncles. Secondly, as for the conceptuses, semiquantitative, statistical analyses were performed of the lengths of chorio-allantois, amnion and yolk sac; and the different parts of the centre and two extremes of the yolk sacs were also analysed. Thirdly, the embryos/foetuses corresponding to their membranes were measured by their greatest length and by weight, and described by the appearance of external developmental phenomena during the investigated period like neurulation, somites, branchial arcs, brain vesicles, limb buds, C-form, pigmented eye and facial grooves. In conclusion, all the data collected in this study from days 20 to 70 of bovine pregnancy were compared extensively with corresponding data of the literature. This resulted in an ,embryo/foetal age-scale', which has extended the data in the literature by covering the first 8 to 70 days of pregnancy. This age-scale of early bovine intrauterine development provides model for studies, even when using slaughtered cows without distinct knowledge of insemination or fertilization time, through macroscopic techniques. This distinctly facilitates research into the cow, which is now being widely used as ,an experimental animal' for testing new techniques of reproduction like in vitro fertilization, embryo transfer and cloning. [source]

Circadian Variation in QT Dispersion Determined from a 12-Lead Holter Recording: A Methodological Study of an Age- and Sex-Stratified Group of Healthy Subjects

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2007
Stig Hansen M.D.
Background: QT dispersion is considered to reflect inhomogeneity of myocardial repolarization. Method: The circadian variation of QT interval dispersion was examined in 95 healthy subjects using 24-hour Holter monitoring. Three different methods of lead selection were applied: all 12 leads (QTdisp 12), only precordial leads (QTdisp 6), and the pair of leads selected at 3 a.m. in which the longest and shortest QT intervals were found in each individual subject (QTdisp 2). Results: A preliminary methodological study including measurements from every minute in 10 subjects revealed no significant circadian variation using mean values of QTdisp 12, QTdisp 6, or QTdisp 2 obtained every hour, every 2, or every 4 hours, except in QTdisp 6, which demonstrated a significant circadian variation (P < 0.01) in 1-hour measurements. Analysis of all 95 subjects using measurements obtained every 4 hours revealed a significant circadian variation in QTdisp 12 and QTdisp 6 (P < 0.0001), whereas no circadian variation was seen in QTdisp 2. A subdivision into 10-year age groups revealed that subjects at age >50 years had a significant circadian variation in QTdisp 12 and QTdisp 6, but not in QTdisp 2. Only in males a significant circadian variation was seen in QTdisp 12 (P < 0.0001), whereas QTdisp 6 demonstrated a circadian variation both in females (P < 0.001) and in males (P < 0.0001). Conclusions: Selection of leads is of crucial importance for repetitive measurements of QT dispersion. Circadian variation was detected in subjects over 50 years of age, when all 12 or only the 6 precordial leads were taken into account. [source]

Meßtechnische Erfassung von Lage und Verformung eines Stahltragwerks unter Temperatureinfluß

BAUTECHNIK, Issue 2 2004
Hans Schulz Dipl.-Ing.
An einem Abschnitt des stählernen Traggerüsts der Wuppertaler Schwebebahn wurden über einen längeren Zeitraum dreidimensionale geodätische Messungen durchgeführt, um die Verformungen von Stahlbauwerken unter Temperaturlast zu untersuchen. Aus einem genauen geodätischen Netz heraus wurden die Koordinaten von am Objekt vermarkten Punkten bei gleichzeitiger Erfassung der Stahltemperatur bestimmt. Ziele der Untersuchungen waren, die mit einem Standardmeßverfahren in der Praxis erreichbaren Meßunsicherheiten für Kontroll-, Überwachungs- und Absteckungsvermessungen an komplexen Stahlkonstruktionen zu ermitteln und gleichzeitig zu überprüfen, ob sich die Konstruktion unter Temperaturlast dem Materialgesetz entsprechend verhält. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Recording of position and deformation of a steel structure with geodetic measurements under varying climatic conditions. Repeated geodetic 3d-measurements on a part of the steel construction of the Wuppertal Suspension Railway were carried out to analyse the influence of the momentarily prevailing steel temperature on the geometry of the construction. Based on a precise geodetic network the coordinates of points marked out on the construction were determined simultaneously recording the steel temperature. The objectives of the measurement were on the one hand to derive the measuring uncertainties, that can be achieved in practice for control and setting-out measurements on complex steel constructions applying a standard method, and on the other hand to check if the behaviour of the construction under temperature load is according to the material's law. [source]

Antagonists of ionotropic ,-aminobutyric acid receptors impair the NiCl2 -mediated stimulation of the electroretinogram b-wave amplitude from the isolated superfused vertebrate retina

ACTA OPHTHALMOLOGICA, Issue 8 2009
Siarhei A Siapich
Abstract. Purpose:, NiCl2 (15 ,M) stimulates the electroretinogram (ERG) b-wave amplitude of vertebrate retina up to 1.5-fold through its blocking of E/R-type voltage-gated Ca2+ channels. Assuming that such an increase is mediated by blocking the release of the inhibitory neurotransmitter ,-aminobutyric acid (GABA) via ionotropic GABA receptors, we tested the effect of both GABA itself and GABA-receptor antagonists such as (,)bicuculline (1.51-fold increase) and (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA; 1.46-fold increase) on the b-wave amplitude. Methods:, Recording of the transretinal potentials from the isolated bovine retina. Results:, GABA (100 ,M) reduced the b-wave amplitude only when NiCl2 (15 ,M) was applied first. Each antagonist applied on its own stimulated the b-wave amplitude only partially: subsequent NiCl2 superfusion caused a small but additional increase, leading to a 1.69- and a 1.88-fold total increase of the amplitude by Ni2+ plus (,)bicuculline or Ni2+ plus TPMPA, respectively. Only the application of both antagonists in combination, before superfusing low NiCl2 (15 ,M), completely prevented subsequent stimulation by NiCl2 with a similar 1.90-fold total increase of b-wave amplitude. Those retina segments that did not respond to NiCl2 could not be stimulated by (,)bicuculline and vice versa. Conclusion:, The stimulatory effect of NiCl2 on the ERG b-wave amplitude is mainly, but not only, mediated by a NiCl2 -sensitive, Cav2.3-triggered GABA release acting through ionotropic GABA-A and GABA-C receptors. [source]

Tris-Cyclometalated Iridium(III) Complexes of Carbazole(fluorenyl)pyridine Ligands: Synthesis, Redox and Photophysical Properties, and Electrophosphorescent Light-Emitting Diodes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2007
Sylvia Bettington Dr.
Abstract Using ligands synthesized by Suzuki cross-coupling methodology, new phosphorescent homoleptic tris-cyclometalated complexes have been obtained, namely fac -[Ir(Cz-2-FlnPy)3] (1,d,f) and fac -[Ir(Cz-3-FlnPy)3] (2,d,f), which are solution-processible triplet emitters (Cz denotes N -hexylcarbazole, n is the number of 9,9,-dihexylfluorene (Fl) units (n=0,1,2) and Py is pyridine). In all cases, Py and Fl are substituted at the 2- and 2,7-positions, respectively, and Cz moieties are substituted by either Py or Fl at the 2- or 3-positions, in series 1 and 2, respectively. The oxidation potential of 1,d studied by cyclic voltammetry (=0.14,V, versus Ag/AgNO3, CH2Cl2) is less positive (i.e. raised HOMO level) compared to that of the isomer 2,d (=0.30,V), where the Cz-nitrogen is meta to the Ir center. Ligand-centered oxidations occur at more positive potentials, leading to 7+ oxidation states with good chemical reversibility and electrochemical quasi-reversibility, for example, for 2,f =0.45 (1e), 0.95 (3e), 1.24,V (3e). Striking differences are seen in the solution-state photophysical data between complexes [Ir(Cz-2-Py)3] (1,d) and [Ir(Cz-3-Py)3] (2,d), in which the Cz moiety is bonded directly to the metal center: for the latter there is an 85,nm blue-shift in emission, a decrease in the luminescence lifetime and an increase in the PLQY value. Organic light emitting devices were made by spin-coating using polyspirobifluorene:bis(triphenyl)diamine (PSBF:TAD) copolymer as host and the complexes 1,d or 2,d as dopants. Turn-on voltages are low (3,4,V). With 1,d orange light is emitted at ,max=590,nm with an EQE of 1.3,% (at 7.5,mA,cm,2) and an emission intensity (luminance) of 4354,cd,m,2 (at 267,mA,m,2). The green emission from 2,d devices (,max=500,nm) is due to the reduced electron-donating ability of the carbazole unit in 2,d. Recording the EL spectra of the 1,d device at 6,V (current density, 100,mA,cm,2) established that the time to half brightness was about 9,h under continuous operation with no change in the spectral profile, confirming the high chemical stability of the complex. [source]

Ensemble Measurement of Diffusion: Novel Beauty and Evidence

CHEMPHYSCHEM, Issue 15 2009
Christian Chmelik Dr.
Abstract Recording the evolution of concentration profiles in nanoporous materials opens a new field of diffusion research with particle ensembles. The technique is based on the complementary application of interference microscopy and IR micro-imaging. Combining the virtues of diffusion measurements with solids and fluids, it provides information of unprecedented wealth and visual power on transport phenomena in molecular ensembles. These phenomena include the diverging uptake and release patterns for concentration-dependent diffusivities, the mechanisms of mass transfer at the fluid,solid interface and opposing tendencies in local and global concentration evolution. [source]