Direct pulp capping of permanent teeth in New Zealand general dental practice--a practice based research study.

OBJECTIVES: This study aimed to investigate treatment protocols and opinions towards direct pulp capping (DPC) amongst New Zealand (NZ) general dental practitioners (GDP) through a Practice Based Research Network (PBRN) study. DESIGN: Mixed-methods approach using qualitative thematic and quantitative analysis. METHODS: An on-line survey containing Likert scale items and open-ended questions was distributed to GDPs on the Dental Council of New Zealand (DCNZ) register (2012) to collect information on practitioner demographics, treatment protocols, continuing professional development (CPD) and philosophies towards DPC. RESULTs: Two hundred and ten GDPs from North and South Islands providing care in main centres and rural areas engaged with the PBRN and participated in the study. Almost all performed DPC treatment although it was not a common procedure. DPC was perceived as 'successful' or 'very successful' by 95% of respondents, mostly for cases of reversible pulpitis. Most provided DPC for patients of all ages but younger patients were perceived to have the best clinical outcomes. Calcium hydroxide and MTA were the most commonly used materials for DPC. MTA was believed to have the best outcome but cost and handling properties were barriers to its use. The majority of respondents had participated in CPD related to vital pulp therapy and regarded this treatment as conservative and providing time and financial benefits compared with more invasive treatment. Clinicians' timeframes for assessing healing were variable, and combined clinical and radiographic findings were considered most useful. CONCLUSION: New Zealand dentists perceive DPC as a successful and conservative treatment in selected cases. The findings have provided insights into engagement of NZ dentists in using research to inform everyday clinical practice through a PBRN study.

How Cooper pairs vanish approaching the Mott insulator in Bi2Sr2CaCu2O8+delta.

The antiferromagnetic ground state of copper oxide Mott insulators is achieved by localizing an electron at each copper atom in real space (r-space). Removing a small fraction of these electrons (hole doping) transforms this system into a superconducting fluid of delocalized Cooper pairs in momentum space (k-space). During this transformation, two distinctive classes of electronic excitations appear. At high energies, the mysterious 'pseudogap' excitations are found, whereas, at lower energies, Bogoliubov quasi-particles-the excitations resulting from the breaking of Cooper pairs-should exist. To explore this transformation, and to identify the two excitation types, we have imaged the electronic structure of Bi(2)Sr(2)CaCu(2)O(8+delta) in r-space and k-space simultaneously. We find that although the low-energy excitations are indeed Bogoliubov quasi-particles, they occupy only a restricted region of k-space that shrinks rapidly with diminishing hole density. Concomitantly, spectral weight is transferred to higher energy r-space states that lack the characteristics of excitations from delocalized Cooper pairs. Instead, these states break translational and rotational symmetries locally at the atomic scale in an energy-independent way. We demonstrate that these unusual r-space excitations are, in fact, the pseudogap states. Thus, as the Mott insulating state is approached by decreasing the hole density, the delocalized Cooper pairs vanish from k-space, to be replaced by locally translational- and rotational-symmetry-breaking pseudogap states in r-space.

Interplay of electron-lattice interactions and superconductivity in superconductivity in Bi2Sr2CaCu2O8+delta.

Formation of electron pairs is essential to superconductivity. For conventional superconductors, tunnelling spectroscopy has established that pairing is mediated by bosonic modes (phonons); a peak in the second derivative of tunnel current d2I/dV2 corresponds to each phonon mode. For high-transition-temperature (high-T(c)) superconductivity, however, no boson mediating electron pairing has been identified. One explanation could be that electron pair formation and related electron-boson interactions are heterogeneous at the atomic scale and therefore challenging to characterize. However, with the latest advances in d2I/dV2 spectroscopy using scanning tunnelling microscopy, it has become possible to study bosonic modes directly at the atomic scale. Here we report d2I/dV2 imaging studies of the high-T(c) superconductor Bi2Sr2CaCu2O8+delta. We find intense disorder of electron-boson interaction energies at the nanometre scale, along with the expected modulations in d2I/dV2 (refs 9, 10). Changing the density of holes has minimal effects on both the average mode energies and the modulations, indicating that the bosonic modes are unrelated to electronic or magnetic structure. Instead, the modes appear to be local lattice vibrations, as substitution of 18O for 16O throughout the material reduces the average mode energy by approximately 6 per cent--the expected effect of this isotope substitution on lattice vibration frequencies. Significantly, the mode energies are always spatially anticorrelated with the superconducting pairing-gap energies, suggesting an interplay between these lattice vibration modes and the superconductivity.

Imaging the impact on cuprate superconductivity of varying the interatomic distances within individual crystal unit cells.

Many theoretical models of high-temperature superconductivity focus only on the doping dependence of the CuO(2)-plane electronic structure. However, such models are manifestly insufficient to explain the strong variations in superconducting critical temperature, T(c), among cuprates that have identical hole density but are crystallographically different outside of the CuO(2) plane. A key challenge, therefore, has been to identify a predominant out-of-plane influence controlling the superconductivity, with much attention focusing on the distance d(A) between the apical oxygen and the planar copper atom. Here we report direct determination of how variations in interatomic distances within individual crystalline unit cells affect the superconducting energy-gap maximum Delta of Bi(2)Sr(2)CaCu(2)O(8+delta). In this material, quasiperiodic variations of unit cell geometry occur in the form of a bulk crystalline "supermodulation." Within each supermodulation period, we find approximately 9 +/- 1% cosinusoidal variation in local Delta that is anticorrelated with the associated d(A) variations. Furthermore, we show that phenomenological consistency would exist between these effects and the random Delta variations found near dopant atoms if the primary effect of the interstitial dopant atom is to displace the apical oxygen so as to diminish d(A) or tilt the CuO(5) pyramid. Thus, we reveal a strong, nonrandom out-of-plane effect on cuprate superconductivity at atomic scale.

Analysis of materials for splinting of the thermally injured patient.

Good results have been achieved in the treatment of patients with burns with new splinting materials and proper splinting techniques. This article focuses on the thermoplastic splinting materials Clinic and Spectrum (Northcoast Medical Inc., San Jose, Calif.) and the comparable thermoplastic products Polyform (Smith & Nephew Rolyan, Inc., Menomonee Falls, Wis.) and Orthoplast (Johnson & Johnson Orthopedics, New Brunswick, N.J.). Qualities such as self-bonding, recyclability, and rigidity were tested for these materials. Splint rigidity was measured by a calibrated hook scale and determined by the force per pound needed to bend the material 20 degrees. Spectrum and Clinic products were judged more economical and, we contend, they are therefore better choices for splinting the thermally injured patient.

Exercise stress testing for the pediatric patient with burns: a preliminary report.

There is no literature concerning postburn exercise tolerance among pediatric patients. In an effort to quantify the endurance capabilities of pediatric burn victims, stress testing of 59 patients was carried out with a modified Bruce protocol. This treadmill test consists of eight 3-minute stages with incremental increases in speed and incline. Fifty-nine patients (37 boys and 22 girls) were tested. The mean burn surface area was 46%; an average of 33% consisted of full-thickness burns. The average time since burn injury at which patients were tested was 2.9 +/- 1.9 years. The average age of the patients at the time of test was 11.4 +/- 3.9 years. No differences in exercise tolerance were found among these children irrespective of the presence of inhalation injury, method of excision, or burn size. If these trends continue as more data are accumulated, the long-term prognosis for the child with severe burns will be encouraging.

The role of gentamicin iontophoresis in the treatment of burned ears.

Ear cartilage heals slowly, and limited vascularity in cartilage precludes use of systemic antibiotics. Iontophoresis electrically induces drugs in solution to migrate into target tissues. Fifteen patients were randomized to receive gentamicin iontophoresis (n = 7) plus dressing changes every 6 hours and cleaning or routine care alone (n = 8) for treatment of ear burns. There were no differences between the groups in incidence of chondritis (43% vs 50%) or cartilage loss (11% vs 16%). However, gentamicin-resistant organisms developed in 29% of the patients who received iontophoresis, but in none of the patients in the control group (p less than 0.05). To identify the etiology of the resistant organisms, 10 New Zealand white rabbits receive 7 cm2 contact burns to each ear. Gentamicin iontophoresis was performed on one ear, and the other ear served as the control. Serum gentamicin levels were always subtherapeutic. Additionally, gentamicin tissue levels in both the treated and control ears were subtherapeutic. Gentamicin iontophoresis appears to offer no additional salutary effects beyond those that are provided by routine care and may encourage the development of antibiotic resistance.

Longitudinal hand grip and pinch strength recovery in the child with burns.

Hand strength of seven patients was evaluated prospectively. A range-of-motion exercise program, compression therapy, and splinting schedules were provided. Fine prehension; lateral, tip-to-tip, and tripod pinch were measured by pinch meter. Grip strength was measured by dynamometer. Comparisons were made between test strengths and published norms for age and sex with analysis of variance. Significance was accepted at p < 0.05. At discharge, all four strength measurements were significantly less than normal for age and sex. Grip and tripod strengths were improved by 6 weeks. All measurements were improved at 6 months after discharge, although grip and lateral pinch remained significantly less than norms. In conclusion, the measurements of tip-to-tip and tripod pinch at 6 months may not signify limitations in performance of activities of daily living. In spite of significantly lower than normal grip and lateral strength measurements at 6 months, it cannot be determined whether this hinders performance of daily living skills.

Relationship of fever magnitude to rate of serious bacterial infections in infants aged 4-8 weeks.

We correlated the height of fever with underlying infectious etiology in 683 consecutive febrile infants aged four to eight weeks who received outpatient evaluation for sepsis during a five-year period. The relative number of infants with fever was inversely proportional to fever height, as 51% had a temperature 38.1-38.9 degrees C, 45% had a temperature 39-39.9 degrees C, and 4% had a temperature greater than or equal to 40 degrees C [hyperpyrexia]. There were 34 cases of serious bacterial infections [SBI], including 16 cases of urinary tract infection, 8 cases of bacteremia, 6 cases of bacterial meningitis, and 4 cases of Salmonella enteritis. The rate of SBI increased in direct proportion to fever height, being 3.2% in those with a temperature 38.1-38.9 degrees C, 5.2% in those with a temperature 39-39.9 degrees C, and 26% in those with a temperature greater than or equal to 40 degrees C. The 6.8% rate of SBI in those with fever greater than or equal to 39 degrees C was significantly greater than the 3.2% rate in those with fever less than 39 degrees C [p less than 0.035]; and the 26% rate of SBI in those with hyperpyrexia was significantly greater than the 4.1% rate in those with fever less than 40 degrees C [p less than 0.000004]. In identifying those with SBI, the presence of hyperpyrexia had a sensitivity of 21%, specificity of 97%, positive-predictive value of 25%, and negative-predictive value of 96%.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and biological evaluation of bupropion analogues as potential pharmacotherapies for cocaine addiction.

A series of bupropion (1a) analogues (1b-1ff) were synthesized, and their in vitro and in vivo pharmacological properties evaluated with the goal of developing a 1a analogue that had better properties for treating addictions. Their in vitro pharmacological properties were examined by [(3)H]dopamine ([(3)H]DA), [(3)H]serotonin ([(3)H]5HT), and [(3)H]norepinephrine ([(3)H]NE) uptake inhibition studies, and by binding studies at the dopamine, serotonin, and norepinephrine transporters using [(125)I]RTI-55 in cloned transporters. Several analogues showed increased [(3)H]DA uptake inhibition with reduced or little change in [(3)H]5HT and [(3)H]NE uptake inhibition relative to bupropion. Thirty-five analogues were evaluated in a 1 h locomotor activity observation test and 32 in an 8 h locomotor activity observation test and compared to the locomotor activity of cocaine. Twenty-four analogues were evaluated for generalization to cocaine drug discrimination after i.p. administration, and twelve analogues were tested in a time course cocaine discrimination study using oral administration. 2-(N-Cyclopropylamino)-3-chloropropiophenone (1x) had the most favorable in vitro efficacy and in vivo pharmacological profile for an indirect dopamine agonist pharmacotherapy for treating cocaine, methamphetamine, nicotine, and other drugs of abuse addiction.

Internal structure of multiphase zinc-blende wurtzite gallium nitride nanowires.

In this paper, the internal structure of novel multiphase gallium nitride nanowires in which multiple zinc-blende and wurtzite crystalline domains grow simultaneously along the entire length of the nanowire is investigated. Orientation relationships within the multiphase nanowires are identified using high-resolution transmission electron microscopy of nanowire cross-sections fabricated with a focused ion beam system. A coherent interface between the zinc-blende and wurtzite phases is identified. A mechanism for catalyst-free vapor-solid multiphase nanowire nucleation and growth is proposed.

Universal high energy anomaly in the angle-resolved photoemission spectra of high temperature superconductors: possible evidence of spinon and holon branches.

A universal high energy anomaly in the single particle spectral function is reported in three different families of high temperature superconductors by using angle-resolved photoemission spectroscopy. As we follow the dispersing peak of the spectral function from the Fermi energy to the valence band complex, we find dispersion anomalies marked by two distinctive high energy scales, E1 approximately 0.38 eV and E2 approximately 0.8 eV. E1 marks the energy above which the dispersion splits into two branches. One is a continuation of the near parabolic dispersion, albeit with reduced spectral weight, and reaches the bottom of the band at the Gamma point at approximately 0.5 eV. The other is given by a peak in the momentum space, nearly independent of energy between E1 and E2. Above E2, a bandlike dispersion reemerges. We conjecture that these two energies mark the disintegration of the low-energy quasiparticles into a spinon and holon branch in the high Tc cuprates.

Effects of pairing potential scattering on Fourier-transformed inelastic tunneling spectra of high-Tc cuprate superconductors with bosonic modes.

Recent scanning tunneling microscopy (STM) experimentally observed strong gap inhomogeneity in Bi2Sr2CaCu2O(8+delta) (BSCCO). We argue that disorder in the pair potential underlies the gap inhomogeneity, and investigate its role in the Fourier-transformed inelastic tunneling spectra as revealed in the STM. We find that the random pair potential induces unique q-space patterns in the local density of states (LDOS) of a d-wave superconductor. We consider the effects of electron coupling to various bosonic modes and find the pattern of LDOS modulation due to coupling to the B(1g) phonon mode to be consistent with the one observed in the inelastic electron tunnneling STM experiment in BSCCO. These results suggest strong electron-lattice coupling as an essential part of the superconducting state in high-Tc materials.

Elastic scattering susceptibility of the high temperature superconductor Bi2Sr2CaCu2O(8+delta): a comparison between real and momentum space photoemission spectroscopies.

The joint density of states of Bi2Sr2CaCu2O(8+delta) is calculated by evaluating the autocorrelation of the single particle spectral function A(k, omega) measured from angle resolved photoemission spectroscopy (ARPES). These results are compared with Fourier transformed (FT) conductance modulations measured by scanning tunneling microscopy (STM). Good agreement between the two experimental probes is found for two different doping values examined. In addition, by comparing the FT-STM results to the autocorrelated ARPES spectra with different photon polarization, new insight on the form of the STM matrix elements is obtained. This shines new light on unsolved mysteries in the tunneling data.

Atomic-Scale Sources and Mechanism of Nanoscale Electronic Disorder in Bi2Sr2CaCu2O8+delta.

The randomness of dopant atom distributions in cuprate high-critical temperature superconductors has long been suspected to cause nanoscale electronic disorder. In the superconductor Bi2Sr2CaCu2O8+delta, we identified populations of atomic-scale impurity states whose spatial densities follow closely those of the oxygen dopant atoms. We found that the impurity-state locations are strongly correlated with all manifestations of the nanoscale electronic disorder. This disorder occurs via an unanticipated mechanism exhibiting high-energy spectral weight shifts, with associated strong superconducting coherence peak suppression but very weak scattering of low-energy quasi-particles.

Coincidence of checkerboard charge order and antinodal state decoherence in strongly underdoped superconducting Bi2Sr2CaCu2O8 + delta).

The doping dependence of nanoscale electronic structure in superconducting Bi(2)Sr(2)CaCu(2)O(8 + delta) is studied by scanning tunneling microscopy. At all dopings, the low energy density-of-states modulations are analyzed according to a simple model of quasiparticle interference and found to be consistent with Fermi-arc superconductivity. The superconducting coherence peaks, ubiquitous in near-optimal tunneling spectra, are destroyed with strong underdoping and a new spectral type appears. Exclusively in regions exhibiting this new spectrum, we find local "checkerboard" charge ordering of high energy states, with a wave vector of Q = (+/- 2pi/4.5a(0),0); (0, +/- 2pi/4.5a(0)) +/- 15%. Surprisingly, this spatial ordering of high energy states coexists harmoniously with the low energy Bogoliubov quasiparticle states.

Acute and subchronic toxicity of pentachlorobenzene.

Oral LD50 values for pentachlorobenzene (QCB) in rats were 1125, 1080, and 940 mg/kg for adult males, adult females, and weanling females, respectively. The oral LD50 values in mice were 1175 mg/kg for males and 1370 mg/kg for females. Clinical signs of toxicity included tremors and narcosis. Dermal application of 2500 mg/kg did not produce clinical signs in rats. In subchronic studies weanling male rats were fed 0, 125, or 1000 ppm QCB for 100 days and weanling females fed 0, 125, 250, 500, or 1000 ppm for 180 days. No clinical signs of toxicity or effects on growth were observed in these rats throughout the exposures. QCB accumulated in adipose tissues at approximately 1.5-2.2 times the dietary concentrations. Porphyrin measurements were made only in females. Terminal values for urinary uro-and coproporphyrin and accumulation of liver porphyrins were not remarkably different in control and QCB-treated groups. In groups fed 1000 ppm, the WBC was increased and red blood cell indices were generally decreased compared to controls. The rats were pair-bred with untreated partners after 67 days of treatment. Fertility and fecundity were unaffected in either sex; however, suckling pups of QCB-treated mothers fed 250 ppm or more developed tremors and at 1000 ppm most died before weaning. Adrenal weights in males and kidney weights in both sexes were increased in adults fed 1000 ppm. In groups fed 250 ppm or more liver/body weight ratios were increased in both adults and in weanling offspring of QCB-treated dams. Hepatocellular enlargement was particularly evident in the 500 and 1000 ppm groups. In the kidneys of adult males, more numerous and larger foci of tubular atrophy and lymphocytic infiltration were seen at 1000 ppm than were seen in controls and dose-related increases in hyaline droplet formation occurred at 125 and 1000 ppm.

Conditions for acid catalysed luminal nitrosation are maximal at the gastric cardia.

BACKGROUND: Saliva has a high nitrite concentration, derived from the enterosalivary recirculation of dietary nitrate, and is the main source of nitrite entering the acidic stomach. Acidification of nitrite in the presence of secondary amines or amides generates potentially carcinogenic N-nitroso compounds. The reaction is inhibited by ascorbic acid and catalysed by thiocyanate. AIM: To determine whether there is intragastric regional variation in the chemical conditions promoting luminal nitrosation following nitrate ingestion. METHODS: Using microdialysis probes, we measured concentrations of nitrite, ascorbic acid, total vitamin C, and thiocyanate simultaneously in saliva, the distal oesophagus, cardia, and the proximal and distal stomach of 17 healthy volunteers before and following intragastric nitrate (2 mmol) administration. RESULTS: The median pH in the distal oesophagus, cardia, and proximal and distal stomach were 7, 2.6, 1.9, and 1.7, respectively, before, and were similar following nitrate administration. Mean nitrite concentration in the distal oesophagus was similar to that of saliva, being 29.1 micro M and 36.7 micro M, respectively, before nitrate and increasing to 181.6 micro M and 203.3 micro M after nitrate ingestion. Within the stomach, mean (SEM) nitrite concentration following nitrate was higher in the cardia (45.5 (12.7) micro M) than in the mid (7.8 (3.1)) (p<0.01) or distal (0.8 (0.6)) (p<0.1) stomach, and ascorbic acid concentration was lower at the cardia (13.0 (6.1)) than in the mid (51 (19.2)) (p<0.02) or distal (86 (29)) (p<0.01) stomach. Consequently, the median ascorbic acid to nitrite ratio was lowest at the cardia (0.3) (p<0.01) versus the mid (7.8) or distal (40) stomach. Thiocyanate concentration was similar throughout the stomach. CONCLUSIONS: The conditions favouring luminal generation of N-nitroso compounds from dietary nitrate are maximal at the most proximal cardia region of the acidic stomach and may contribute to the high incidence of mutagenesis at this site.