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Geothermal energy has traditionally been viewed as a baseload energy source, but the rapid growth of intermittent renewable energy has led to a need for more flexibility in power generation to avoid mandatory curtailment imposed by grid operators. This study of curtailment at The Geysers provides insights into the magnitude, duration, frequency, temporal and spatial distribution, and potential causes of curtailment events between 2013 and 2018. Annual levels of curtailment range during this period from 9 to 47 GW h, representing 0.15 to 0.81 % of the net generation. Most curtailments occurred at the power plants connected to a lower capacity transmission line and may result from transmission constriction. There is a clear link between negative pricing and economic curtailment, especially when solar production is higher. Economic curtailment events tend to be only a few hours and vary in magnitude up to almost 300 MW, whereas transmission-related curtailment events can be up to several weeks in duration. It is likely that curtailment of geothermal power will be an increasing concern, and could be mitigated by flexible generation strategies and increases in energy storage. It is critical to know the nature of curtailment events so that flexible generation options can be assessed properly.

Background: Chlorhexidine varnish (Cervitec- Ivoclar Vivadent- Liechtenstein) is a sustained-release delivery system that can provide protection against white spots and gingivitis, which are common iatrogenic side effects of orthodontic treatment. Chlorhexidine in varnish form does not depend on patient compliance, does not stain teeth or alter taste sensation like the mouth rinse. Materials and Methods : A split-mouth technique was followed in the treatment of 30 patients selected by stringent selection criteria, evaluating a single application of the test varnish on two randomly allotted quadrants along with a placebo on the other two quadrants. Streptococcus mutans counts responsible for white spots and P. gingivalis count [using PCR test] responsible for gingivitis were done at the start of the study, and then 1 and 3 months later. Results: The chlorhexidine varnish reduced the Streptococci mutans count at the end of 1 month, and this reduction was statistically significant. At the end of 3 months, there was no difference in the S. mutans counts between the two groups. There was a statistically significant reduction in the P. gingivalis count at the end of both 1 and 3 months in comparison to the placebo group. Conclusion: Chlorhexidine varnishes are capable of reducing S. mutans and P. gingivalis and gingivitis, thus improving the overall oral health of the patient. The side effects of chlorhexidine mouth rinses are not seen with this varnish. An application schedule of at least once a month is recommended as the effectiveness is reduced comparatively at the end of 3 months.

Aim: To evaluate the demineralization resistance and the shear bond strength of enamel surfaces after erbium, chromium: yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser etching (2 W/15 Hz, 2 W/25 Hz) and to compare them with conventional acid etching for orthodontic bonding. Materials and Methods: A total of 60 extracted human premolars with intact enamel surface were used for this study. Demineralization Resistance was estimated using ion-coupled plasma atomic emission spectrometer (ICP-AES). Shear bond strength was evaluated using Universal Testing Machine--Instron. Results: Statistically significant difference (P < .001) was found in the concentration of dissolved calcium (Ca) and phosphorus (P), with the highest mean Ca and P in the acid-etched group, followed by 2 W/15 Hz laser-etched group and least with 2 W/25 Hz laser-etched group. Maximum bond strength was found in the acid-etched group (12.06 MPa), followed by the 2 W/25 Hz laser-etched group (9.01 MPa) and 2 W/15 Hz laser-etched group (8.39 MPa). The differences were statistically significant. Conclusions: Laser conditioning of enamel surface revealed significant demineralization resistance with a minimal dissolution of Ca and P ions in the demineralizing solution. Moreover, optimum bond strength was obtained similar to that of acid etching; hence, Er,Cr:YSGG laser conditioning of enamel surface is preferred over the conventional phosphoric acid etching for orthodontic bonding. [ABSTRACT FROM AUTHOR]

Aims: To compare antigen extraction efficiency of chemical methods such as benzyl alcohol, chloroform, sodium citrate, extraction buffer with Tween‐20 (EBT) and isopropyl myristate for determination of 146S content in the fresh and stored FMD oil‐adjuvanted vaccines. Methods and Results: Standard vaccine with antigen payload of 10, 5 and 5 µg per cattle dose (2 ml) for serotypes O, A and Asia1, respectively, was used to compare the antigen extraction efficiency of five chemical methods: benzyl alcohol, chloroform, sodium citrate, EBT buffer and isopropyl myristate. The purity of the extracted 146S antigen was quantified by caesium chloride (CsCl) ultracentrifugation. Serotype‐specific sandwich ELISA (sELISA) was developed to identify the serotype and to compare the 146S in aqueous phase and ultrafractions. The antigen recovery was also tested in stored trivalent vaccine. Coefficient of regression was calculated to assess the predictive power of the benzyl alcohol extraction method. Of the five methods, benzyl alcohol showed consistent antigen recovery of >90% in monovalent as well as trivalent vaccines. Ultrafraction showed a 1·4 ratio at A259/239 nm in UV spectrophotometry indicating the presence of 146S. sELISA revealed that the antigen recovery was significantly less in ultrafractions than that of aqueous phase. Further, there was no significant difference in antigen recovery from stored trivalent vaccine for 12 months, indicating the usefulness of the benzyl alcohol method. Linear regression model revealed R2 = 0·99 with a narrow band of predictive interval. Conclusions: The benzyl alcohol method was efficient in extracting 146S from the monovalent and trivalent fresh and stored FMD vaccines. CsCl density gradient precisely quantified the 146S, while sELISA identified the serotype of the vaccine. Significance and Impact of the Study: When the benzyl alcohol method is coupled with CsCl density gradient and sELISA, it has the potential to determine the 146S content of FMD vaccine. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effects of three adhesion boosters-All-Bond 2, Enhance LC, and Ortho Solo-on the shear bond strength of new and rebonded (previously debonded) brackets. Methods: One hundred new and 100 sandblasted debonded brackets were bonded to 200 extracted human premolars and divided into eight groups. Results: The new brackets/Ortho Solo group yielded the highest bond strength, followed by the new brackets/All-Bond 2 and the new brackets/Enhance LC groups. During rebonding, Ortho Solo improved the bond strength significantly; however, All-Bond 2 and Enhance LC did not. Conclusion: (1) Bond strength is significantly improved when new brackets are bonded with an adhesion booster; (2) without any adhesion booster, sandblasted rebonded brackets yield a significantly lower bond strength than new brackets; (3) Enhance LC failed to improve the bond strength of rebonded brackets; (4) Ortho Solo increased the bond strength of rebonded brackets significantly; and (5) brackets rebonded with Ortho Solo yielded comparable bond strength as new brackets without any adhesion booster. [ABSTRACT FROM AUTHOR]

This article describes the treatment of an adult female with periodontally induced bone loss, excessive gingival display when smiling, vertical maxillary excess, a convex profile, a traumatic deep overbite, and severe lip incompetence. The therapy included four steps: (1) periodontal flap surgery and root planing with regular follow-ups; (2) leveling and aligning of the maxillary and mandibular arch with closure of all spaces, the extraction of mandibular first premolars, and retraction of the mandibular incisors; (3) LeFort I two-segment osteotomy with removal of the second premolars and a 5-mm impaction to reduce the excessive gingival display and permit autorotation of the mandible to decrease the facial convexity. To close the extraction space, the posterior segment was set 4 mm anteriorly and the anterior segment 3 mm posteriorly; and (4) postsurgical orthodontics for finishing and detailing. The treatment lasted 36 months; improved facial esthetics significantly; and resulted in a normal occlusion, overjet, and overbite. [ABSTRACT FROM AUTHOR]