Low concentrations of selenium nanoparticles enhance the performance of a generalist parasitoid and its host, with no net effect on host suppression.

BACKGROUND: The environmental and economic costs of conventional insecticides have stirred an interest in alternative management tactics, including the use of nanotechnologies. Selenium nanoparticles (SeNPs) have many applications in agriculture but may not be compatible with biological control; however, low concentrations of SeNPs may benefit natural enemies via hormesis. This study investigates the concentration-dependent effects of SeNPs (0-1000 mg L-1 ) on Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), a generalist parasitoid of stored product pests. RESULTS: The LC50 of SeNPs was 1540 mg L-1 for female parasitoids and 1164 mg L-1 for males. SeNPs had a significant hormetic effect; average lifespan increased by 10% at a concentration of 4.03 mg L-1 for females and by 35% at 13.83 mg L-1 for males. In a bioassay including hosts [the azuki bean beetle, Callosobruchus chinensis (L.) (Coleoptera: Chrysomelidae: Bruchinae)], a low concentration of SeNPs (25 mg L-1 ) enhanced the performance of female parasitoids; lifespan increased by 23% and the number of offspring increased by 88%. However, the number of emerging hosts did not significantly decrease; in the absence of parasitism, SeNPs actually improved host emergence by 17%. CONCLUSION: Because higher concentrations of SeNPs reduced parasitoid lifespan, whereas low concentrations enhanced not only parasitoid performance but also host emergence, practitioners should exercise caution when considering SeNPs for use in integrated pest management. © 2023 Society of Chemical Industry.

Clinical and Radiographic Evaluation of a Novel Triangular Implant Neck Design: A Case Series.

The objective of this study was to evaluate the clinical and radiographic behavior of a novel triangular neck implant configuration in partially edentulous patients. Sixteen patients with a mean age of 58.3 years, were rehabilitated with 25 implants inserted in the healed sites of the maxilla and mandible; implant diameter was Ø3.3 and 3.9 mm. Clinical and radiographic measurements were first performed at prosthesis delivery that served as baseline; they were further evaluated after a mean period of 15.6 months. The interproximal peri-implant bone levels were the primary outcome; the mesial and distal data were recorded and a mean value was calculated. Secondary outcomes included peri-implant probing depth (PPD) and bleeding on probing (BoP). The paired t-test was used to compare the radiographic and clinical outcomes between baseline and follow-up. The mean bone levels at the mesial and distal aspects at baseline were 0.45 (0.47) and 0.57 (0.69), respectively; at follow-up they were 0.59 (0.42) and 0.78 (0.59), respectively. The differences were not statistically significant. Similarly, no significant differences were found for the clinical parameters. Within the limitations of the present study, it could be concluded that this new triangular neck bone level implant macro-design was used successfully to treat partially edentulous patients. Larger controlled clinical studies are warranted to confirm the present radiographic and clinical findings.

Adjunctive efficacy of systemic metronidazole in the surgical treatment of periodontitis: a double-blind parallel randomized clinical trial.

OBJECTIVES: The purpose of this study was to evaluate the clinical and microbiological impact of adjunctive metronidazole to periodontal surgery. MATERIALS AND METHODS: Systemically healthy patients, with stages III-IV, grades B-C periodontitis, were randomly assigned to receive metronidazole or placebo adjunctive to periodontal surgery, after subgingival instrumentation. Clinical variables were recorded at the initial visit, 6 weeks after subgingival instrumentation, and 3, 6, and 12 months after surgery. Microbiological samples were taken at initial and final visits and analyzed by quantitative polymerase chain reaction. RESULTS: Our results showed no statistically significant differences in the reduction of probing depth between the initial and final (1 year) visits in the two treatment groups. Additionally, no statistically significant differences were observed between study groups when comparing the post-subgingival instrumentation and final visits. However, 3 months after surgery, probing depth (mean difference, MD = 0.31 mm, 95% confidence interval, CI [0.13; 0.49]; p = 0.001) and clinical attachment level (MD = 0.64 mm, 95% CI [0.02; 1.27]; p = 0.044) were significantly lower in the test group. CONCLUSIONS: The adjunctive use of systemic metronidazole to periodontal surgery has a limited clinical and microbiological impact in the present study, and therefore, its use is not recommended. CLINICAL RELEVANCE: There are no studies that have evaluated the clinical and microbiological impact of the adjunctive use of systemic metronidazole to periodontal surgery (step 3 of periodontal therapy). The results of the present study do not support the adjunctive use of systemic metronidazole to periodontal surgery.

Impact of a nonnative parasitoid species on intraspecific interference and offspring sex ratio.

In an assemblage of multiple predators sharing a single prey species, the combined effects of the component species may scale unpredictably because of emergent interspecific interactions. Prior studies suggest that chaotic but persistent community dynamics are induced by intra-/interspecific interactions between native and nonnative parasitoids competing over a shared host. Here, we test the impact of the nonnative parasitoid Heterospilus prosopidis (Hymenoptera: Braconidae) on the intraspecific interference and offspring sex ratio of the native parasitoid Anisopteromalus calandrae (Hymenoptera: Pteromalidae). We found that the nonnative parasitoid reduced intraspecific interference among native parasitoids and decreased the proportion of female offspring produced by the native parasitoid (predicted under conditions of reduced host availability). At higher host densities, the nonnative parasitoid contributed less to the total proportion of hosts parasitized, as its innate saturating Type II response changed to a dome-shaped Type IV response with increasing density of the native parasitoid, while the native parasitoid retained its increasing Type I response. This inverse host-density-dependent response between the two parasitoids and associated competitive superiority can explain the observed changes in parasitism; at high host densities, the searching efficiency of the native parasitoid increases via host feeding while the nonnative parasitoid experiences egg limitation. These results highlight the importance of the complementary top-down effects of multiple consumers on a single resource.

Can we clinically identify pre-symptomatic and asymptomatic COVID-19?

ObjectivesCOVID-19 has had a severe impact on morbidity and mortality among nursing home (NH) residents. Earlier detection of SARS-CoV-2 may position us to better mitigate risk of spread. Both asymptomatic or pre-symptomatic transmission are common in outbreaks, and threshold temperatures, such as 38C, for screening for infection could miss timely detection in the majority. DesignRetrospective cohort study using electronic health records MethodsWe hypothesized that in long-term care residents, temperature trends with SARS-CoV-2 infection could identify infection in pre-symptomatic and asymptomatic individuals earlier. We collected information about age and other demographics, baseline temperature, and specific comorbidities. We created standardized definitions, and an alternative hypothetical model to test measures of temperature variation and compare outcomes to the VA reality. Settings and participantsOur subjects were 6,176 residents of the VA NHs who underwent SARS-CoV-2 trigger testing. ResultsWe showed that a change from baseline of >0.4C identifies 47% of the SARS-CoV-2 positive NH residents early, and achieves earlier detection by 42.2 hours. Range improves early detection to 55% when paired with a 37.2C cutoff, and achieves earlier detection by 44.4 hours. Temperature elevation >0.4C from baseline, when combined with a 0.7C range, would detect 52% early, leading to earlier detection by more than 3 days in 22% of the residents. This earlier detection comes at the expense of triggering 57,793 tests, as compared to the number of trigger tests ordered in the VA system of 40,691. Conclusion and implicationsOur model suggests that current clinical screening for SARS-CoV-2 in NHs can be substantially improved upon by triggering testing using a patient-derived baseline temperature with a 0.4C degree relative elevation or temperature variability of 0.7C trigger threshold for SARS-CoV2 testing. Such triggers could be automated in facilities that track temperatures in their electronic records.

Anti-inflammatory effect of salt water and chlorhexidine 0.12% mouthrinse after periodontal surgery: a randomized prospective clinical study.

OBJECTIVES: The purpose of this study was to compare the anti-inflammatory efficacy of sodium chloride- and a 0.12% chlorhexidine mouth rinses in patients undergoing minimal invasive periodontal surgery. MATERIALS AND METHODS: Forty-seven patients with a diagnosis of periodontitis and indication for access flap procedure were randomly selected. Group A: a sodium chloride (salt)water-based mouth rinse (test group) or group B: a 0.12% chlorhexidine mouth rinse (control group) administered after surgery. Gingival Index (GI) were evaluated in the whole mouth and in the surgical site at baseline (T1), a week later (T2), and 12 weeks (T3) after the treatment. Total MMP activity was measured in GCF using a commercial kit and plate reader. Medians of total MMP activity and GI were compared for time intervals T1 vs. T2, T1 vs. T3, and T2 vs T3 using Friedman tests and Wilcoxon signed rank tests, and were also compared between test and control using Mann-WhitneyU tests at each timepoint. RESULTS: The average GI values showed significant differences between baseline and T2 (p = 0.0005) and baseline and T3 (p = 0.003) in the test group. CONCLUSION: The sodium chloride-mouth rinse use after periodontal surgery seems to have similar anti-inflammatory properties as CHX mouth rinse and can be used regularly postoperatively after periodontal surgical procedures. CLINICAL RELEVANCE: The use of salt water mouthwash showed an anti-inflammatory effect similar to CHX 0.12% after minimal invasive periodontal surgery. Salt water mouthwash is accessible to the world population and can contribute on the healing process after periodontal surgery.

Gingival phenotype and its relationship with different clinical parameters: a study in a Dominican adult sample.

OBJECTIVES: The purpose of this study was to estimate the prevalence of thin and thick gingival phenotype (GPh) in a sample of Dominican subjects and correlate it with clinical parameters. MATERIALS AND METHODS: One-hundred seven periodontal healthy volunteers in the range of 18-73 years were enrolled in the study. GPh was defined by the transparency of a periodontal probe through the buccal gingival margin on the upper right or left central incisor. Clinical periodontal parameters such as keratinized gingiva width (WKG), attached gingiva width (WAG), probing depth (PD), plaque index (PI), and gingival index (GI) were recorded by a calibrated examiner. Frequency distribution of qualitative variables was calculated. For quantitative variables, Mann-Whitney and Kruskal-Wallis tests were used for comparison of groups. RESULTS: There was no association between GPh and sex. There were no significant differences between thin and thick GPh regarding age, PD, GI, and interproximal index. The association between tooth morphology and GPh was significant (p = 0.018). Median amount of keratinized gingiva was significantly larger (p = 0.01) in subjects with thin gingival phenotype (median = 6.00 mm) when compared with subjects with thick gingival phenotype (median = 5 mm). CONCLUSIONS: Subjects with thin GPh presented larger WKG. Furthermore, there was an association between tooth morphology and GPh. CLINICAL RELEVANCE: This is the first study to report the distribution of gingival phenotype and its relationship with different periodontal parameters of a Caribbean population. Our findings can contribute to the clinicians when planning or performing dental procedures.

Density-dependent lifespan and estimation of life expectancy for a parasitoid with implications for population dynamics.

Parasitoid lifespan is influenced by nutrient availability, thus the lifespan of parasitoids that rely on their hosts for nutritional resources (either via host feeding or by consuming honeydew) should vary with host density. We assessed the survival and reproduction of one such species, Aphelinus certus-a parasitoid of the soybean aphid, Aphis glycines-over a range of host densities using a laboratory assay. We found a positive, asymptotic relationship between host density and the lifespan and fecundity of A. certus that was supported by a traditional survivorship analysis as well as a logistic model. Parasitoids from this assay were also used to develop a wing wear index relating setae damage to parasitoid age. This index was used to estimate the life expectancy of field-collected parasitoids, which was shorter than the life expectancy of laboratory-reared female parasitoids. Finally, host-density-dependent parasitoid lifespan was incorporated into a coupled-equations matrix population model that revealed that decreasing the degree of host density dependence leads to higher equilibrium host densities and changes in the quality of equilibrium (e.g. stable limit cycles). These results detail the relatively unstudied phenomenon of host-density-dependent parasitoid lifespan and suggest that differences between laboratory- and field-determined parasitoid life expectancy have important implications for population dynamics and the biological control of insects.

Distalization rate of maxillary canines in an alveolus filled with leukocyte-platelet-rich fibrin in adults: A randomized controlled clinical split-mouth trial.

INTRODUCTION: The objective of this study was to evaluate the distalization rate and changes in inclination of the maxillary canines in alveoli preserved with leukocyte-platelet-rich fibrin (L-PRF) membranes in adult patients. The null hypothesis was that there are no differences in the canine distalization movement rate between the treated and the control sides. METHODS: A total of 21 healthy adult patients with a minimum age of 20 years (mean age, 33 ± 5.9 years) and Angle Class I or Class II Division 1 malocclusion, who had an indication of extraction of the maxillary first premolars and orthodontic distalization of the maxillary canines were included in this study. A randomized controlled clinical split-mouth trial was conducted; the experimental maxillary side was treated with L-PRF membranes, and the other side served as the control. A randomization sequence of the experimental sides among patients was generated using the random number generation function of Microsoft Excel. Neither the patients nor the operators were blinded. Fifteen days after the extractions, distalization was initiated using an elastic chain applying 150 g of force to the canines on a 0.020-in stainless steel archwire. The distalization rate was the main outcome of the study, and it was assessed monthly for 5 months through the intraoral use of a flexible ruler. The degree of inclination of the canines was the secondary outcome, and it was evaluated through cone-beam computed tomography. A Shapiro-Wilk test was performed, and a Wilcoxon signed rank test was subsequently used to compare the experimental and the control group. Spearman rank correlation coefficient was calculated to evaluate the correlation between distalization and inclination for each side. RESULTS: Four of the subjects dropped out of the study, leaving a total of 17 patients (n = 17). The distalization rate and inclination of the canines were greater on the control side than on the side treated with L-PRF (P <0.05). A weak correlation was found between the distalization rate and inclination of the canines for both sides (control side, ρ = 0.17; experimental, ρ = 0.11). No harm was observed during the study. CONCLUSIONS: The null hypothesis was rejected. The use of L-PRF in young adult patients decreased the rate of distalization and changes in inclination of the maxillary canines compared with the control group. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement.

A matrix model describing host-parasitoid population dynamics: The case of Aphelinus certus and soybean aphid.

Integrating elements from life tables into population models within a matrix framework has been an underutilized method of describing host-parasitoid population dynamics. This type of modeling is useful in describing demographically-structured populations and in identifying points in the host developmental timeline susceptible to parasitic attack. We apply this approach to investigate the effect of parasitism by the Asian parasitoid Aphelinus certus on its host, the soybean aphid (Aphis glycines). We present a matrix population model with coupled equations that are analogous to a Nicholson-Bailey model. To parameterize the model, we conducted several bioassays outlining host and parasitoid life history and supplemented these studies with data obtained from the literature. Analysis of the model suggests that, at a parasitism rate of 0.21 d-1, A. certus is capable of maintaining aphid densities below economically damaging levels in 31.0% of simulations. Several parameters-parasitoid lifespan, colonization timeline, host developmental stage, and mean daily temperature-were also shown to markedly influence the overall dynamics of the system. These results suggest that A. certus might provide a valuable service in agroecosystems by suppressing soybean aphid populations at relatively low levels of parasitism. Our results also support the use of A. certus within a dynamic action threshold framework in order to maximize the value of biological control in pest management programs.

Clinical and histological evaluation of socket grafting using different types of bone substitute in adult patients.

PURPOSE: This clinical and histological study evaluated the healing of extraction sockets after implantation of a biphasic calcium sulfate (CS) alone or in combination with a gamma-radiated human mineralized allograft. MATERIALS AND METHODS: Ten healthy adult patients participated in the study. A minimum of 2 teeth, per patient, extracted for different reasons were evaluated. Each socket was randomly filled to the crest with either (a) a biphasic CS or (b) large particulate gamma-radiated human mineralized allograft in combination with a biphasic CS. RESULTS: No complications during reentry of the socket site during bone core retrieval, such as inflammation/immunogenic response, were observed. Histological findings showed a mean new bone (NB) of 33% for sockets filled with biphasic CS and 31% for sockets filled with biphasic CS in combination with allograft material. There was no statistically significant difference in the percentage of NB and the presence of soft tissue between graft materials. CONCLUSION: Biphasic CS used alone or in combination with an allograft resulted in the same amount of NB formation in alveolar ridge preservation procedures.

Evaluation of human peri-implant soft tissues around alumina-blasted/acid-etched standard and platform-switched abutments.

This study evaluated the histometric characteristics of the peri-implant mucosa of human subjects that received textured implant abutments with conventional (implant and abutment with same diameter) or platform-switched (implant diameter wider than that of the abutment) configurations. Wider and longer connective tissue around platform-switched implants was observed compared to that with conventional abutments. Despite the different dimensions between the two abutment types, the abutment-soft tissue interaction was similar for both groups at the histometric level.