Does a black light lens aid in composite removal?

OBJECTIVE: To evaluate the effectiveness of a black light lens as visual aid in composite restoration removal. Lost tooth structure, residual composite, and removal time were compared for operators with different levels of experience. METHODS: Occlusal preparations in 24 matched-pair extracted molars were etched, bonded, restored with composite, and thermocycled. The restored teeth were radiographed and two faculty and two student doctors removed the restorations with or without a black light lens while time was recorded. Digital scans of the cavity before and after restoration removal were used to calculate lost tooth structure and residual composite. RESULTS: Removal of restorations resulted in tooth structure loss and left residual composite. The use of the black light lens had no significant effect (two-way ANOVA; p value >0.05). However, operator experience significantly affected operating times and average depth of tooth structure loss (two-way ANOVA; p value <0.05). Student doctors assisted by the black light lost less tooth structure than experienced operators and improved their operating times (multiple comparisons; p value <0.05). CONCLUSIONS: The black light lens did not conserve tooth structure or avoid composite remnants compared to routine operation, nor affected the operating time. However, less-experienced operators did benefit from the black light in conserving tooth structure and time. CLINICAL SIGNIFICANCE: Replacement of defective composite restorations is a regular practice in restorative dentistry. When existing composite restorations are removed, loss of tooth structure is unavoidable. A black light lens might improve the ability of operators with less experience to conserve tooth structure even though it did not provide benefits for the experienced operators.

Background conditions for an urban greenhouse gas network in the Washington, D.C. and Baltimore metropolitan region.

As city governments take steps towards establishing emissions reduction targets, the atmospheric research community is increasingly able to assist in tracking emissions reductions. Researchers have established systems for observing atmospheric greenhouse gases in urban areas with the aim of attributing greenhouse gas concentration enhancements (and thus, emissions) to the region in question. However, to attribute enhancements to a particular region, one must isolate the component of the observed concentration attributable to fluxes inside the region by removing the background, which is the component due to fluxes outside. In this study, we demonstrate methods to construct several versions of a background for our carbon dioxide and methane observing network in the Washington, DC and Baltimore, MD metropolitan region. Some of these versions rely on transport and flux models, while others are based on observations upwind of the domain. First, we evaluate the backgrounds in a synthetic data framework, then we evaluate against real observations from our urban network. We find that backgrounds based on upwind observations capture the variability better than model-based backgrounds, although care must be taken to avoid bias from biospheric carbon dioxide fluxes near background stations in summer. Model-based backgrounds also perform well when upwind fluxes can be modeled accurately. Our study evaluates different background methods and provides guidance determining background methodology that can impact the design of urban monitoring networks.

Greenhouse gas observations from the Northeast Corridor tower network.

We present the organization, structure, instrumentation, and measurements of the Northeast Corridor greenhouse gas observation network. This network of tower-based in situ carbon dioxide and methane observation stations was established in 2015 with the goal of quantifying emissions of these gases in urban areas in the northeastern United States. A specific focus of the network is the cities of Baltimore, MD, and Washington, DC, USA, with a high density of observation stations in these two urban areas. Additional observation stations are scattered throughout the northeastern US, established to complement other existing urban and regional networks and to investigate emissions throughout this complex region with a high population density and multiple metropolitan areas. Data described in this paper are archived at the National Institute of Standards and Technology and can be found at https://doi.org/10.18434/M32126 (Karion et al., 2019).

Managing a Lateral Periodontal Cyst With Bone Graft: A Computed Tomography Assessment 18 Months Postoperatively.

The lateral periodontal cyst is a rare benign lesion that is generally asymptomatic and commonly discovered by routine intraoral radiography. Reports on proper management of this lesion are readily available. However, the literature is sparse regarding the long-term outcomes following surgery. A traditional radiographic technique does not provide an adequate image of the healing, and a patient may resist the prospect of a reentry procedure. The current report is the first to utilize a cone-beam computed tomography scan to evaluate the healing potential of a freeze-dried bone allograft approximately 18 months postoperatively.

Development of stable lyophilized protein drug products.

Freeze drying, or lyophilization is widely used for biopharmaceuticals to improve the long term storage stability of labile molecules. This review examines general theory and practice of rational lyophilization of biopharmaceuticals. Formulation development involving the selection of appropriate excipients, their associated physical properties, and mechanism of action in achieving a stable drug product are primary considerations for a successful lyophilization program. There are several parameters considered critical on the basis of their relationship to lyophilization cycle development and protein product stability. This along with the importance of analytical methods to provide insight toward understanding properties of drug product stability and cake structure are discussed. Also, aspects of instability found in lyophilized biopharmaceutical products, their degradation pathways and control are elucidated. Finally, container-closure requirements and drug product handling are described in context of the caveats to avoid compromising drug product quality.

Pharmacological inhibition of Rho-kinase signaling with Y-27632 blocks melanoma tumor growth.

Primarily through in vitro studies, the Rho-family of small GTPases and their effector proteins have been implicated in mediating oncogenic properties of cancer cells. We sought to determine if pharmacological inhibition of the RhoA effector proteins known as Rho-kinases (ROCK) with the small molecule inhibitor Y-27632 could inhibit melanoma in vitro and in vivo. We demonstrate that Y-27632 treatment of a panel of melanoma cells alters cellular morphology leading to spindly cells with decreased lamellipodia and increased filopodia formation. Y-27632 treatment decreases invasion and alters cell survival of cultured melanoma cells. IP injection of Y-27632 in tumor-bearing mice resulted in a reduction in melanoma tumor volume compared to control treated mice. These findings suggest that ROCK inhibition can reduce melanoma tumorigenicity.

Active dimer of Epratuzumab provides insight into the complex nature of an antibody aggregate.

Understanding the intermolecular products of antibodies as a consequence of host-cell expression, aging, and heat-stress can be insightful especially when it involves the development of a stable biopharmaceutical product. The dimerized form of Epratuzumab (an IgG(1) antibody) with a molecular mass of approximately 300 kDa (twice the monomer antibody molecular weight of approximately 150 kDa) was examined to gain a better perspective of its properties pertaining to structure and activity. The nascent dimer was shown to partially dissociate upon incubation at 30 degrees C and 37 degrees C, exhibit no discernable alteration of structure (i.e., secondary or tertiary structure based on CD and 2nd derivative UV spectroscopy), have approximately 70% covalent forms (based upon CE-SDS results) and manifest twofold higher activity relative to the active monomer form (on a weight basis the dimer and monomer have equal activity). Interestingly, these properties were not attributed to a single dimer species, but rather to a more complex dimer assembly. The Epratuzumab dimer was digested with papain to reveal three uniquely dimerized aggregates. The relative molar distribution of Fab:Fab, Fc:Fc, and Fab:Fc was found to be 4:3:8, respectively. The data suggest that all three predominantly covalent dimer adducts are capable of full activity, shedding light on their complex nature and showing that their target specificity was unaltered. ESI-MS data indicated the presence of remnant levels of noncovalent dimers for all three dimerized forms. Material aged at 37 degrees C exhibited a similar papain digest molar distribution of the three dimerized forms, except with enhanced chemical heterogeneity and an increase in covalent forms to approximately 84%.