Chen MY‐H, Chen K‐L, Chen C‐A, Tayebaty F, Rosenberg PA, Lin LM. Responses of immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization ...procedures. International Endodontic Journal, 45, 294–305, 2012.
Aim To report several types of response of immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscess to revascularization procedures.
Methodology Twenty immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscesses from 20 patients were included. The teeth were isolated with rubber dam, and pulp chambers was accessed through the crowns. The canals were gently irrigated with 5.25% sodium hypochlorite with minimal mechanical debridement. Calcium hydroxide was used as an inter‐appointment intracanal medicament and placed into the coronal half of the canal space. After resolution of clinical signs and symptoms, bleeding was induced into the canal space from the periapical tissues using K‐files. The coronal canal space was sealed with a mixture of mineral trioxide aggregate (MTA) and saline solution. The access cavity was filled with composite resin. These immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscesses were followed up from 6 to 26 months.
Results Five types of responses of these immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures were observed: type 1, increased thickening of the canal walls and continued root maturation; type 2, no significant continuation of root development with the root apex becoming blunt and closed; type 3, continued root development with the apical foramen remaining open; type 4, severe calcification (obliteration) of the canal space; type 5, a hard tissue barrier formed in the canal between the coronal MTA plug and the root apex.
Conclusions Based on this case series, the outcome of continued root development was not as predictable as increased thickening of the canal walls in human immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess after revascularization procedures. Continued root development of revascularized immature permanent necrotic teeth depends on whether the Hertwig’s epithelial root sheath survives in case of apical periodontitis/abscess. Severe pulp canal calcification (obliteration) by hard tissue formation might be a complication of internal replacement resorption or union between the intracanal hard tissue and the apical bone (ankylosis) in revascularized immature permanent necrotic teeth.
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and regulate a wide array of light-dependent physiological processes. Genetic ablation of ipRGCs ...eliminates circadian photoentrainment and severely disrupts the pupillary light reflex (PLR). Here we show that ipRGCs consist of distinct subpopulations that differentially express the Brn3b transcription factor, and can be functionally distinguished. Brn3b-negative M1 ipRGCs innervate the suprachiasmatic nucleus (SCN) of the hypothalamus, whereas Brn3b-positive ipRGCs innervate all other known brain targets, including the olivary pretectal nucleus. Consistent with these innervation patterns, selective ablation of Brn3b-positive ipRGCs severely disrupts the PLR, but does not impair circadian photoentrainment. Thus, we find that molecularly distinct subpopulations of M1 ipRGCs, which are morphologically and electrophysiologically similar, innervate different brain regions to execute specific light-induced functions.
How turbulent energy is dissipated in weakly collisional space and astrophysical plasmas is a major open question. Here, we present the application of a field-particle correlation technique to ...directly measure the transfer of energy between the turbulent electromagnetic field and electrons in the Earth's magnetosheath, the region of solar wind downstream of the Earth's bow shock. The measurement of the secular energy transfer from the parallel electric field as a function of electron velocity shows a signature consistent with Landau damping. This signature is coherent over time, close to the predicted resonant velocity, similar to that seen in kinetic Alfven turbulence simulations, and disappears under phase randomisation. This suggests that electron Landau damping could play a significant role in turbulent plasma heating, and that the technique is a valuable tool for determining the particle energisation processes operating in space and astrophysical plasmas.
This study aims to determine the occurrence and behavior of five classes of 20 antibiotics in both water and sedimentary phases in the Huangpu River, which supplies drinking water to Shanghai City, ...China. Of the 20 antibiotics, sulfonamides showed the highest concentrations in water samples (34-859 ng L(-1)) while tetracyclines (average concentration at 18 μg kg(-1) dry weight) and macrolides (12 μg kg(-1) dry weight) dominated in sediment samples. The spatial distribution of antibiotics showed that the main polluting sources into the river were animal farming sites and the tributaries downstream of the Yuanxie River. In addition, linear relationships between logKoc and logKow, and between logKoc and log molecular weight, were demonstrated, suggesting the importance of contaminant properties in inter-phase behavior. The environmental risk assessment revealed that some antibiotics, in particular sulfamethoxazole could cause medium damage to daphnid in the aquatic ecosystem.
The recent advent of transition‐metal mediated CH activation is revolutionizing the synthetic field and gradually infusing a “CH activation mind‐set” in both students and practitioners of organic ...synthesis. As a powerful testament of this emerging synthetic tool, applications of CH activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of CH activation as a strategic manoeuver are compared with their “non‐CH activation” counterparts, illuminating a new paradigm in strategic synthetic design.
The total synthesis of natural products has been carried out showcasing the creative and ingenious application of CH activation in the construction of complex molecular architectures that are compared with their “non‐CH activation” counterparts. These accomplishments stood as true testaments of the growing potential of CH activation, and further cementing the power of this emerging synthetic technology (see figure).
This study comprehensively investigates the changing biodistribution of fluorescent-labelled polystyrene latex bead nanoparticles in a mouse model of inflammation. Since inflammation alters systemic ...circulatory properties, increases vessel permeability and modulates the immune system, we theorised that systemic inflammation would alter nanoparticle distribution within the body. This has implications for prospective nanocarrier-based therapies targeting inflammatory diseases. Low dose lipopolysaccharide (LPS), a bacterial endotoxin, was used to induce an inflammatory response, and 20 nm, 100 nm or 500 nm polystyrene nanoparticles were administered after 16 hours. HPLC analysis was used to accurately quantify nanoparticle retention by each vital organ, and tissue sections revealed the precise locations of nanoparticle deposition within key tissues. During inflammation, nanoparticles of all sizes redistributed, particularly to the marginal zones of the spleen. We found that LPS-induced inflammation induces splenic macrophage polarisation and alters leukocyte uptake of nanoparticles, with size-dependent effects. In addition, spleen vasculature becomes significantly more permeable following LPS treatment. We conclude that systemic inflammation affects nanoparticle distribution by multiple mechanisms, in a size dependent manner.
In this tutorial review, recent advances in the synthesis of cyclopropane-containing natural products are discussed, highlighting the application of novel synthetic methodologies and innovative ...synthetic strategies in the construction of highly functionalized cyclopropanes. The examples showcased herein aim to inspire students and practitioners of organic synthesis to seek further advances in the chemical synthesis of cyclopropanes, both in the context of target-oriented syntheses and method developments.
This paper summarises some of the recent progress that has been made in understanding astrophysical plasma turbulence in the solar wind, from in situ spacecraft observations. At large scales, where ...the turbulence is predominantly Alfvénic, measurements of critical balance, residual energy and three-dimensional structure are discussed, along with comparison to recent models of strong Alfvénic turbulence. At these scales, a few per cent of the energy is also in compressive fluctuations, and their nature, anisotropy and relation to the Alfvénic component is described. In the small-scale kinetic range, below the ion gyroscale, the turbulence becomes predominantly kinetic Alfvén in nature, and measurements of the spectra, anisotropy and intermittency of this turbulence are discussed with respect to recent cascade models. One of the major remaining questions is how the turbulent energy is dissipated, and some recent work on this question, in addition to future space missions which will help to answer it, are briefly discussed.
FeFETs with 5-nm-thick Hf 0.5 Zr 0.5 O 2 (HZO) have been demonstrated in memory operations for the ON/OFF current ratio >10 4 at zero gate voltage and a memory window (MW) of 0.6-0.7 V. A gradual ...transition of the ferroelectricity with an increasing crystallization temperature for the gate-last process was presented. The excellent data retention are the <inline-formula> <tex-math notation="LaTeX">{\sim }\textsf {2}\times \textsf {10}^{\textsf {4}} </tex-math></inline-formula> ON/OFF ratio and 0.67 V extrapolated to ten years with V P/E = ±4.8 V. The MW remains >0.2 V after 10 6 cycles for read and vanishes with cycles of 10 3 −10 4 for write, which is the bottleneck for ferroelectric (FE)-type memories. The mechanism of retention and endurance is discussed. The characteristic of this letter is an unaffected coercive-field (~1 MV/cm) with scaling FE-HZO down to 5-nm thickness, which is beneficial for reducing the operation voltage. A comparable performance with thick HZO (>5 nm) on high data retention and endurance with low voltage for read is achieved. The ultrathin FE layer proposes a realistic emerging memory for 1T architecture.
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