Zeolite-Enhanced Portland Cement: Solution for Durable Wellbore-Sealing Materials

Wellbore-plugging materials are threatened by challenging plugging and abandonment (P&A) conditions. Hence, the integrity and resilience of these materials and their ability to provide sufficient zonal isolation in the long-term are unknown. The present work focuses on investigating the potential to use zeolites as novel additives to the commonly used Class-H cement. Using four different zeolite–cement mixtures (0%, 5%, 15% and 30%, by weight of cement) where samples were cast as cylinders and cured at 90 °C and 95% relative humidity, the unconfined compressive strength (UCS) testing showed a 41% increase with the 5% ferrierite addition to the Class-H cement in comparison to neat Class-H cement. For triaxial compression tests at 90 °C, the highest strength achieved by the 5% ferrierite-added formulations was 68.8 MPa in comparison to 62.9 MPa for the neat Class-H cement. The 5% ferrierite formulation also showed the lowest permeability, 13.54 μD, which is in comparison to 49.53 μD for the neat Class-H cement. The overall results show that the 5% ferrierite addition is the most effective at improving the mechanical and petrophysical properties based on a water/cement ratio of 0.38 when tested after 28 days of curing in 95% relative humidity and 90 °C. Our results not only demonstrate that zeolite is a promising cement additive that could improve the long-term strength and petrophysical properties of cement formulations, but also provide a proposed optimal formulation that could be next utilized in a field trial.     

Laser processing of bioactive tricalcium phosphate coating on titanium for load-bearing implants

Laser-engineered net shaping (LENS), a commercial rapid prototyping (RP) process, was used to coat titanium with tricalcium phosphate (TCP) ceramics to improve bone cell-materials interactions. During LENS coating process, the Nd:YAG laser melts the top surface of Ti substrate in which calcium phosphate powder is fed to create a TCP-Ti composite layer. It was found that an increase in laser power and/or powder feed rate increases the thickness of the coating. However, coating thickness decreased with increasing laser scan speed. TCP coating showed columnar titanium grains at the substrate side of the coating and transitioned to equiaxed titanium grains at the outside. When the scan speed was reduced from 15 to 10mms(-1), coating hardness increased from 882+/-67 to 1049+/-112Hv due to an increase in the volume fraction of TCP in the coating. Coated surfaces showed uniformly distributed TCP particles and X-ray diffraction data confirmed the absence of any undesirable phases, while maintaining a high level of crystallinity. The effect of TCP coating on cell-material interaction was examined by culturing osteoprecursor cells (OPC1) on coated surfaces. The results indicated that TCP coating had good biocompatibility where OPC1 cells attached and proliferated on the coating surface. The coating also initiated cell differentiation, ECM formation and biomineralization.     

Comparison of the Proportion of Non‐Classic (CD14+CD16+) Monocytes/Macrophages in Peripheral Blood and Gingiva of Healthy Individuals and Patients With Chronic Periodontitis

Background: Monocyte subsets with low CD14 expression that coexpress CD16 (CD14+CD16+) are called non‐classic or hyperinflammatory monocytes. Previous studies have reported an increase in the percentage of CD14+CD16+ monocytes in the peripheral blood of patients with chronic periodontitis (CP). To our knowledge, there are no reports demonstrating the presence of CD14+CD16+ monocyte–derived macrophages (MDMs) in the gingival tissue. The objective of this study is to identify the proportion of non‐classic (CD14+CD16+) monocytes/macrophages in peripheral blood and gingiva of healthy individuals and patients with CP. Methods: A total of 60 individuals (n = 30 per group) were recruited for the study. Group 1 included 30 individuals with healthy gingiva, and group 2 included 30 patients with CP. Direct immunofluorescent staining was done in 200 μL whole‐blood and single‐cell suspensions obtained from gingival tissue, with fluorochrome‐conjugated monoclonal antibodies against CD14, CD16, and human leukocyte antigen‐DR (HLA‐DR), and subjected to flow cytometric analysis. Results: The mean percentage of CD14+CD16+ monocytes in the peripheral blood of healthy individuals was 9.10% ± 1.39%, and for patients with CP it was 14.18% ± 2.69% (P <0.05). The mean percentage of CD14+CD16+ MDMs in the gingival tissue of healthy individuals was found to be 0.93% ± 0.33%, whereas in patients with CP, it was 1.92% ± 0.78% (P <0.01). Non‐classic monocytes/macrophages showed a high median fluorescent intensity for HLA‐DR (DR++). Conclusion: This study demonstrates an increased proportion of CD14+CD16+HLA‐DR++ monocytes/macrophages in the peripheral blood and gingiva of patients with CP.     

Effect of poly(amidoamine) (PAMAM) dendrimer on skin permeation of 5-fluorouracil

The aim of present study is to investigate the effect of poly(amidoamine) (PAMAM) dendrimer on skin permeation of 5-fluorouracil (5FU). Permeation studies were performed using excised porcine skin in a Franz diffusion cell and (14)C labeled 5FU samples were analyzed using liquid scintillation counter. Three different vehicles were used, including phosphate buffer (PB), mineral oil (MO) and isopropyl myristate (IPM). The studies were carried out by simultaneously applying the drug and dendrimer together or by pre-treating the skin with dendrimer before drug application. Simultaneous application of drug and dendrimer increased the flux of 5FU in IPM and MO, while there was no change in PB. The increased skin partitioning of dendrimer from lipophilic vehicles increased the drug solubility in skin. Pre-treatment with dendrimer increased permeability coefficient of 5FU by 4-fold in MO and 2.5-fold in IPM, while it decreased by half in PB. Skin partitioning of 5FU increased after dendrimer treatment from lipophilic vehicles. The flux increased linearly with increase in pre-treatment time. Dendrimer pre-treatment increased transepidermal water loss and decreased skin resistance. The decrease in skin resistance directly correlated to the enhancement in skin permeation of 5FU (r(2)=0.99). Overall, the study showed that dendrimer increases the skin permeation of 5FU from lipophilic vehicles mainly by altering the skin barrier.     

Transport of Schisandra chinensis extract and its biologically-active constituents across Caco-2 cell monolayers - an in-vitro model of intestinal transport

We have determined the intestinal transport of Schisandra chinensis extract and its lignans (gomisin A, gomisin N and schisandrin C) in the Caco-2 cell monolayer model. The transport across monolayers was examined for 2 h in absorptive and secretory directions. Quantitation of lignans was performed by HPLC. Out of the three lignans, gomisin A exhibited bi-directional transport, with P(app) values in the range of 25-29 x 10(-6) cm s(-1), indicating a passive diffusion. Gomisin N, mixture and Schisandra extract displayed a higher transport in the secretory direction with efflux ratios in the range of 2.2-5.2. The efflux was decreased in the presence of inhibitors of multidrug resistance protein (MRP) transporter (MK-571) and P-glycoprotein (verapamil) indicating a possible involvement of an efflux pump and MRP in the transport of Schisandra lignans. Poor transport of schisandrin C was observed which could not be quantitated. The permeability of gomisin A in the isolated form was significantly different compared with the mixture or extract.     

Normal pio-dural arterial connections

The arterial blood supply to the dura mater is rich, complex and is derived from both the internal and external carotid systems. Endovascular management of a variety of intracranial diseases necessitates a thorough understanding of the dural arterial network. In this article we review the normal contributions of the pial arteries to the blood supply of the dura mater and discuss some aspects of its role in the supply of dural arteriovenous shunts (DAVS).     

Evaluation of anti-inflammatory activity of chloroform extract of Bryonia laciniosa in experimental animal models

The anti-inflammatory effect of the leaves of Bryonia laciniosa was evaluated using carrageenan, dextran, histamine, serotonin induced rat paw oedema and cotton pellet induced granuloma (chronic) models in rats. In mice, carrageenan peritonitis test was performed for the extract by oral administration. The chloroform extract of Bryonia laciniosa (CEBL) exhibited significant anti-inflammatory effect at the dose 50, 100 and 200 mg/kg. Maximum inhibition (52.4%) was noted at the dose of 200 mg/kg after 3 h of drug treatment in carrageenan induced paw oedema, whereas the indomethacin (standard drug) produced 62.1% of inhibition. The extract exhibited significant anti-inflammatory activity in dextran induced paw oedema in a dose dependent manner. The extract also exhibited significant inhibition on the hind paw oedema in rats caused by histamine and serotonin respectively. In the chronic model (cotton pellet induced granuloma) the CEBL (200 mg/kg) and standard drug showed decreased formation of granuloma tissue by 50.1 and 57.3% (p<0.001) respectively. The extract also inhibited peritoneal leukocyte migration in mice. Thus, the present study revealed that the chloroform extract of Bryonia laciniosa exhibited significant anti-inflammatory activity in the tested models.