As part of the continuing evolution towards conservative dentistry there has been a drive to push further and investigate the possibility of inducing the repair and regeneration of lost dental hard ...tissue. Until recently, the prospect of repair and regeneration had been confined to laboratory studies and hypothesised scientific models. In 2009, a new product was launched claiming to be a revolutionary material capable of offering a bioactive and biocompatible replacement for dentine. The calcium-based cement is reported to preserve pulp vitality, promote pulp healing and provide a natural substitute for dentine through bioactive stimulation of the dentino-pulpal complex. Its clinical indications are extensive, described as a restorative material suitable for use wherever dentine replacement is required. In this article the physical, mechanical, chemical and biological properties of this novel material are presented, together with the results of experimental laboratory-based investigations and on-going clinical in vivo investigations.
Dietary energy density kcal/g (kJ/g) influences energy intake under controlled laboratory conditions. Little is known about the energy density of the diets of free-living persons. Because energy ...density investigations are a relatively new endeavor, there are neither standard calculation methods nor published nationally representative values. This paper examines the calculation of energy density based on systematic exclusion of beverage categories, presents data on variability, and compares values by sex, age, and race/ethnicity in a representative sample of U.S. adults. Mean daily dietary energy density values for adults (aged >19 y) were calculated using two 24-h recalls from the Continuing Survey of Food Intakes by Individuals 1994-1996 based on food, food and liquid meal replacements, food and alcohol, food and juice, food and milk, food and juice and milk, food and energy-containing beverages, and food and all beverages. Energy density varied by calculation method, ranging from 0.94 to 1.85 kcal/g (3.93-7.74 kJ/g). Intraindividual-to-interindividual CV ratios were highest for the food and energy-containing beverages calculation. Men reported diets with a higher energy density than women for all calculation methods (P < 0.0001). There were differences by race/ethnicity and an inverse linear trend for age. These data indicate that beverage inclusion schemes should be clearly defined when reporting energy density values. In epidemiologic studies, calculations based on food and all beverages and food and energy-containing beverages may diminish associations with outcome variables. These nationally representative data, which provide an important frame of reference for other studies, indicate that dietary energy density differs by sex, age, and race/ethnicity.
Three different structures of the composition Li2Ni2TeO6 have been synthesized and their electrochemical properties characterized: a disordered orthorhombic phase with tellurium ordering and strong ...Li/Ni cation mixing, a T#2-layered phase, and an O3-layered phase; each have a distinct cycling performance. The disordered orthorhombic structure is the most stable at room temperature and has the highest capacity with the lowest overpotential. The T#2 phase is the least stable and undergoes a phase transformation once lithium is extracted. Density functional theory calculations reconcile the relative structural stabilities and physical properties of each phase with their electrochemical performances. Calculations also confirmed experimental observations regarding the synthesis of each structure and indicated the mechanism for capacity fade of each Li2Ni2TeO6 cathode. Strong tellurium–oxygen covalent bonding increases the voltage of the Ni2+/3+ redox couple in each of these materials over what is normally observed in layered oxides.
Achieving profound pulpal anaesthesia in a mandibular molar diagnosed with irreversible pulpitis can be argued to be the most testing of dental anaesthetic challenges. This can be attributed to the ...technical complexities of conventional techniques and the presence of pulp pathosis. Reasons for why the latter influences the ability to attain pulpal anaesthesia is not yet fully understood, but its frequent occurrence is well documented. In light of overcoming this it has become common practice to prescribe antibiotics, refer onto secondary care or to even commence treatment without appropriately anaesthetising the tooth. Therefore, this two part series aims to help practitioners attain clinically acceptable pulpal anaesthesia in the most testing of scenarios; the acutely inflamed mandibular molar. They should then be able to apply these same principles to other teeth presenting with similar symptoms. This section outlines the clinical presentation and pathophysiology associated with an acutely inflamed pulp, defines what it is to attain pulpal anaesthesia and critically analyses theories as to why these teeth are up to eight times more difficult to anaesthetise than their healthy counterparts.
Rheo-NMR velocimetry was used to study shear banding of a 6 wt.% cetylpyridinium chloride (CPCl) worm-like micelle solution under shear startup conditions with and without pre-shear. 1D velocity ...profiles across the fluid gap of a concentric cylinder Couette shear cell were measured every 1 s following shear startup for four different applied shear rates within the stress plateau. Fitting of the velocity profiles allowed calculation of the shear banding characteristics (shear rates in the high and low shear band, the interface position and apparent slip at the inner rotating wall) as the flow transitioned from transient to steady state regimes. Characteristic timescales to reach steady state were obtained and found to be similar for all shear banding characteristics. Timescales decreased with increasing applied shear rate. Large temporal fluctuations with time were also observed and Fourier transform of the time and velocity autocorrelation functions quantified the fluctuation frequencies. Frequencies corresponded to the elastically driven hydrodynamic instabilities,
vortices, that are known to occur in the unstable high shear band and were dependent upon both applied shear rate and the pre-shear protocol.
ABSTRACT
FRB 20121102A is the first known fast radio burst (FRB) from which repeat bursts were detected, and one of the best-studied FRB sources in the literature. Here we report on the analysis of ...478 bursts (333 previously unreported) from FRB 20121102A using the 305-m Arecibo telescope – detected during approximately 59 hours of observations between December 2015 and October 2016. The majority of bursts are from a burst storm around September 2016. This is the earliest available sample of a large number of FRB 20121102A bursts, and it thus provides an anchor point for long-term studies of the source’s evolving properties. We observe that the bursts separate into two groups in the width-bandwidth-energy parameter space, which we refer to as the low-energy bursts (LEBs) and high-energy bursts (HEBs). The LEBs are typically longer duration and narrower bandwidth than the HEBs, reminiscent of the spectro-temporal differences observed between the bursts of repeating and non-repeating FRBs. We fit the cumulative burst rate-energy distribution with a broken power law and find that it flattens out toward higher energies. The sample shows a diverse zoo of burst morphologies. Notably, burst emission seems to be more common at the top than the bottom of our 1150–1730 MHz observing band. We also observe that bursts from the same day appear to be more similar to each other than to those of other days, but this observation requires confirmation. The wait times and burst rates that we measure are consistent with previous studies. We discuss these results, primarily in the context of magnetar models.
‘Grandpa was never the same after his operation!’. This statement describes a myriad of possible clinical difficulties that can afflict older people after hospitalisation for major surgery. We ...summarise the evidence pertaining to the phenomenon of Postoperative Cognitive Dysfunction, a condition defined as an abnomality on neuropsychological testing, which is said to afflict up to 14% of over 70 years olds undergoing elective surgery. So far none of the expected surgical, anaesthetic and environmental risk factors have been convincingly demonstrated to be reponsible for this observed deterioration. While recognising the high incidence of the condition as an neuropsychological entity we accept that it is difficult to translate this into a reliable estimate of clinical risk for the individual patient.
We show that the dayside MOPITT retrievals in the lower troposphere can provide useful information on surface sources of atmospheric CO over the Indian subcontinent. We find that MOPITT retrievals at ...850 hPa show localized enhancements over the Indian subcontinent, which correlate with similar enhancements seen in the tropospheric NO2 columns from the SCIAMACHY instrument. In particular, high concentrations of CO over the Indo‐Gangetic basin and some prominent cities are captured in the lower‐tropospheric retrievals in spring. MOPITT averaging kernels (normalized to take into account the absorber amounts in the layers) indicate that the retrievals are sensitive to CO in the lower troposphere. In winter, MOPITT retrievals at 850 hPa can detect the strongest source areas over the eastern states of Bihar and West Bengal, thus confirming the so‐called “Bihar pollution pool,” which was detected earlier in the aerosol measurements by the multiangle imaging spectroradiometer (MISR) aboard Terra. The pollution features are consistent with the spatial distribution of CO emissions in India, as reflected in the GEOS‐Chem simulation of CO. Furthermore, these lower‐tropospheric features in the simulation are still present after smoothing the modeled fields using the MOPITT averaging kernels and a priori profile, demonstrating that the retrievals do have sensitivity in the lower troposphere. This work indicates that although MOPITT retrievals are often most sensitive to CO in the middle and upper troposphere, they do provide information on lower‐tropospheric CO in selected continental regions with strong thermal contrast and could be useful for pollution studies.
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