Objectives
To compare the incidence of biological and technical complications of cemented and screw‐retained monolithic lithium‐disilicate implant‐supported posterior single crowns.
Material and ...Methods
Forty‐one subjects with a total of 56 implants received randomly allocated 28 cemented and 28 screw‐retained crowns. In the screw‐retained group, monolithic lithium‐disilicate restorations were luted to titanium bases extraorally. In the cemented group, monolithic lithium‐disilicate crowns were cemented on individualized titanium abutments intraorally. All restorations were examined according to modified FDI criteria within 2 weeks of inserting the crowns (baseline) and after 12 (n = 46) and 24 (n = 43) months. Bone loss was evaluated by standardized radiographs at baseline and 12 months.
Results
After 12 months, the incidence of mucositis (positive bleeding on probing) was 14.2% (screw‐retained) and 17.9% (cement‐retained). The gingival and plaque index and a mean marginal bone loss between 0.03–0.15 mm showed no significant difference between the groups. In the cemented group, cement residues were detected at baseline at two restorations (6.9%) by radiographic examination. A complete digital workflow was realized in most cases (85.7%). At 24 months, no restoration had failed, and no chipping of the ceramic had occurred. In the screw‐retained group, screw loosening occurred in one implant. In both groups, there was obvious deterioration in the quality of 32% of the occlusal and of 18% of the proximal contact points.
Conclusions
The type of retention mode of monolithic implant‐retained lithium‐disilicate posterior crowns had no influence on the biological and technical complication rate.
Many species are currently experiencing anthropogenically driven environmental changes. Among these changes, increasing noise levels are specifically a problem for species relying on acoustic ...communication. Recent evidence suggests that some species adjust their acoustic signals to man‐made noise. However, it is unknown whether these changes occur through short‐term and reversible adjustments by behavioral plasticity or through long‐term adaptations by evolutionary change. Using behavioral observations and playback experiments, we show that male reed buntings (Emberiza schoeniclus) adjusted their songs immediately, singing at a higher minimum frequency and at a lower rate when noise levels were high. Our data showed that these changes in singing behavior were short‐term adjustments of signal characteristics resulting from behavioral plasticity, rather than a long‐term adaptation. However, more males remained unpaired at a noisy location than at a quiet location throughout the breeding season. Thus, phenotypic plasticity enables individuals to respond to environmental changes, but whether these short‐term adjustments are beneficial remains to be seen.
Geographically structured phenotypic selection can lead to adaptive divergence. However, in flowering plants, such divergent selection has rarely been shown, and selection on floral signals is ...generally little understood. In this study, we measured phenotypic selection on display size, floral color, and floral scent in four lowland and four mountain populations of the nectar-rewarding terrestrial orchid Gymnadenia odoratissima in two years. We also quantified population differences in these traits and pollinator community composition. Our results show positive selection on display size and positive, negative, or absence of selection on different scent compounds and floral color. Selection on the main scent compounds was consistently stronger in the lowlands than in the mountains, and lowland plants emitted higher amounts of most of these compounds. Pollinator community composition also differed between regions, suggesting different pollinators select for differences in floral volatiles. Overall, our study is the first to document consistent regional differences in selection on floral scent, suggesting this pattern of selection is one of the evolutionary forces contributing to regional divergence in floral chemical signaling.
Background and AimsStudies of local floral adaptation in response to geographically divergent pollinators are essential for understanding floral evolution. This study investigated local pollinator ...adaptation and variation in floral traits in the rewarding orchid Gymnadenia odoratissima, which spans a large altitudinal gradient and thus may depend on different pollinator guilds along this gradient.MethodsPollinator communities were assessed and reciprocal transfer experiments were performed between lowland and mountain populations. Differences in floral traits were characterized by measuring floral morphology traits, scent composition, colour and nectar sugar content in lowland and mountain populations.Key ResultsThe composition of pollinator communities differed considerably between lowland and mountain populations; flies were only found as pollinators in mountain populations. The reciprocal transfer experiments showed that when lowland plants were transferred to mountain habitats, their reproductive success did not change significantly. However, when mountain plants were moved to the lowlands, their reproductive success decreased significantly. Transfers between populations of the same altitude did not lead to significant changes in reproductive success, disproving the potential for population-specific adaptations. Flower size of lowland plants was greater than for mountain flowers. Lowland plants also had significantly higher relative amounts of aromatic floral volatiles, while the mountain plants had higher relative amounts of other floral volatiles. The floral colour of mountain flowers was significantly lighter compared with the lowland flowers.ConclusionsLocal pollinator adaptation through pollinator attraction was shown in the mountain populations, possibly due to adaptation to pollinating flies. The mountain plants were also observed to receive pollination from a greater diversity of pollinators than the lowland plants. The different floral phenotypes of the altitudinal regions are likely to be the consequence of adaptations to local pollinator guilds.
Early and frequent antenatal care attendance during pregnancy is important to identify and mitigate risk factors in pregnancy and to encourage women to have a skilled attendant at childbirth. ...However, many pregnant women in sub-Saharan Africa start antenatal care attendance late, particularly adolescent pregnant women. Therefore they do not fully benefit from its preventive and curative services. This study assesses the timing of adult and adolescent pregnant women's first antenatal care visit and identifies factors influencing early and late attendance.
The study was conducted in the Ulanga and Kilombero rural Demographic Surveillance area in south-eastern Tanzania in 2008. Qualitative exploratory studies informed the design of a structured questionnaire. A total of 440 women who attended antenatal care participated in exit interviews. Socio-demographic, social, perception- and service related factors were analysed for associations with timing of antenatal care initiation using regression analysis.
The majority of pregnant women initiated antenatal care attendance with an average of 5 gestational months. Belonging to the Sukuma ethnic group compared to other ethnic groups such as the Pogoro, Mhehe, Mgindo and others, perceived poor quality of care, late recognition of pregnancy and not being supported by the husband or partner were identified as factors associated with a later antenatal care enrolment (p < 0.05). Primiparity and previous experience of a miscarriage or stillbirth were associated with an earlier antenatal care attendance (p < 0.05). Adolescent pregnant women started antenatal care no later than adult pregnant women despite being more likely to be single.
Factors including poor quality of care, lack of awareness about the health benefit of antenatal care, late recognition of pregnancy, and social and economic factors may influence timing of antenatal care. Community-based interventions are needed that involve men, and need to be combined with interventions that target improving the quality, content and outreach of antenatal care services to enhance early antenatal care enrolment among pregnant women.
Two highly correlated anther traits affect pollination efficacy in a wild radish population. Does the strength and type of selection on these traits differ through male and female fitness with ...increased ancestral trait variation? Waterman et al. (2023) found stabilizing selection on one trait and disruptive selection on the other trait, with no difference between male and female fitness. Such quantifications of selection in populations with the increased variation that reflects ancestral trait variation provide insights into processes of trait adaptation.
Floral isolation is an important component of pollinator-driven speciation. However, up to now, only a few studies have quantified its strength and relative contribution to total reproductive ...isolation. In this study, we quantified floral isolation among three closely related, sympatric orchid species of the genus Ophrys by directly tracking pollen flow. Ophrys orchids mimic their pollinators' mating signals, and are pollinated by male insects during mating attempts. This pollination system, called sexual deception, is usually highly specific. However, whether pollinator specialization also conveys floral isolation is currently under debate. In this study, we found strong floral isolation: among 46 tracked pollen transfers in two flowering seasons, all occurred within species. Accounting for observation error rate, we estimated a floral isolation index ≥0.98 among each pair of species. Hand pollination experiments suggested that postpollination barriers were effectively absent among our study species. Genetic analysis based on AFLP markers showed a clear species clustering and very few F₁ hybrids in natural populations, providing independent evidence that strong floral isolation prevents significant interspecies gene flow. Our results provide the first direct evidence that floral isolation acts as the main reproductive barrier among closely related plant species with specialized pollination.
There is a recognised need for innovative methods to elicit the perspective of adolescents on public health issues, particularly when addressing sensitive topics such as the impact of mining projects ...on their health. Participatory approaches such as "photovoice" allow for deep engagement of vulnerable and marginalised populations, including adolescents. However, few existing studies have used the photovoice method to reflect on issues related to the environment and its impact on public health. To date, no studies have been found that have used photovoice to gain insight into adolescents' perspectives in mining areas. In this paper, we discuss the application of the photovoice method to understand adolescents' perceptions about the impact of mining on their health and well-being in rural areas in Mozambique. The study was conducted in northern and central Mozambique. Photovoice was successfully integrated into eight focus group discussions with adolescent girls and boys aged 15 to 17 years. Several lessons for guiding future research were learned. First, it provided an understanding of the perceived impacts of mining on their health and well-being. Second, photovoice promoted active engagement and interest in the study by the adolescents. Finally, compared to its ability to capture perceptions of physical and environmental aspects affecting adolescents' well-being, the method was less straightforward in revealing their concerns regarding social, relational and community aspects that are less tangible. Programs can make use of photovoice to address health issues without setting adolescents' views and priorities aside, allowing them to influence health decisions on issues that are meaningful to them. Future studies should explore strategies to minimise the role of the power dynamics that affect the engagement and contribution of adolescents in advocating for necessary and meaningful changes. Additionally, it is important to investigate how health programs and policies can help to reduce the impact of existing inequalities.
The bi-component leukocidins of Staphylococcus aureus are important virulence factors that lyse human phagocytic cells and contribute to immune evasion. The γ-hemolysins (HlgAB and HlgCB) and ...Panton-Valentine leukocidin (PVL or LukSF) were shown to assemble from soluble subunits into membrane-bound oligomers on the surface of target cells, creating barrel-like pore structures that lead to cell lysis. LukGH is the most distantly related member of this toxin family, sharing only 30–40% amino acid sequence identity with the others. We observed that, unlike other leukocidin subunits, recombinant LukH and LukG had low solubility and were unable to bind to target cells, unless both components were present. Using biolayer interferometry and intrinsic tryptophan fluorescence we detected binding of LukH to LukG in solution with an affinity in the low nanomolar range and dynamic light scattering measurements confirmed formation of a heterodimer. We elucidated the structure of LukGH by x-ray crystallography at 2.8-Å resolution. This revealed an octameric structure that strongly resembles that reported for HlgAB, but with important structural differences. Structure guided mutagenesis studies demonstrated that three salt bridges, not found in other bi-component leukocidins, are essential for dimer formation in solution and receptor binding. We detected weak binding of LukH, but not LukG, to the cellular receptor CD11b by biolayer interferometry, suggesting that in common with other members of this toxin family, the S-component has the primary contact role with the receptor. These new insights provide the basis for novel strategies to counteract this powerful toxin and Staphylococcus aureus pathogenesis.
LukGH is a member of the family of two-component bacterial toxins of Staphylococcus aureus that lyse human phagocytic cells.
The crystal structure of LukGH and mutagenesis revealed the molecular basis for heterodimer formation in solution.
LukGH differs from other two-component leukocidins that interact only upon cell contact.
These data might assist with development of therapeutics that counteract Staphylococcus aureus pathogenesis.
Staphylococcus aureus pneumonia is associated with high mortality irrespective of antibiotic susceptibility. Both MRSA and MSSA strains produce powerful cytotoxins: alpha-hemolysin(Hla) and up to ...five leukocidins - LukSF-PV, HlgAB, HlgCB, LukED and LukGH (LukAB) - to evade host innate defense mechanisms. Neutralizing cytotoxins has been shown to provide survival benefit in rabbit S. aureus pneumonia models. We studied the mechanisms of protection of ASN100, a combination of two human monoclonal antibodies (mAbs), ASN-1 and ASN-2, that together neutralize Hla and the five leukocidins, in rabbit MRSA and MSSA pneumonia models. Upon prophylactic passive immunization, ASN100 displayed dose-dependent increase in survival and was fully protective against all S. aureus strains tested at 5 or 20 mg/kg doses. Macroscopic and microscopic lung pathology, edema rate, and bacterial burden were evaluated 12 hours post infection and reduced by ASN100. Pharmacokinetic analysis of ASN100 in bronchoalveolar-lavage fluid from uninfected animals detected efficient penetration to lung epithelial lining fluid reaching peak levels between 24 and 48 hours post dosing that were comparable to the mAb concentration measured in serum. These data confirm that the ASN100 mAbs neutralize the powerful cytotoxins of S. aureus in the lung and prevent damage to the mucosal barrier and innate immune cells.
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