Effects of intermittent fasting on periodontal inflammation and subgingival microbiota

BACKGROUND

Studies on the impact of intermittent fasting on periodontal health are still scarce. Thus, this study evaluated the effects of long-term intermittent fasting on periodontal health and the subgingival microbiota.

METHODS

This pilot study was part of a nonrandomized controlled trial. Overweight/obese participants (n = 14) entered an intermittent fasting program, specifically the 5:2 diet, in which they restricted caloric intake to about a quarter of the normal total daily caloric expenditure for two nonconsecutive days/week. Subjects underwent a thorough clinical and laboratory examination, including an assessment of their periodontal condition, at baseline and 6 months after starting the diet. Additionally, subgingival microbiota was assessed by 16S rRNA gene sequencing.

RESULTS

After 6 months of intermittent fasting, weight, body mass index, C-reactive protein, hemoglobin A1c (HbA1c), and the cholesterol profile improved significantly (p < 0.05). Moreover, significant reductions were observed in bleeding on probing (p = 0.01) and the presence of shallow periodontal pockets after fasting (p < 0.001), while no significant change was seen in plaque index (p = 0.14). While we did not observe significant changes in α- or β-diversity of the subgingival microbiota related to dietary intervention (p > 0.05), significant differences were seen in the abundances of several taxa among individuals exhibiting ≥60% reduction (good responders) in probing pocket depth of 4-5 mm compared to those with <60% reduction (bad responders).

CONCLUSION

Intermittent fasting decreased systemic and periodontal inflammation. Although the subgingival microbiota was unaltered by this intervention, apparent taxonomic variability was observed between good and bad responders.

Cathodoluminescence investigations of dark-line defects in platelet-based InGaN nano-LED structures

We have investigated the optical properties of heterostructured InGaN platelets aiming at red emission, intended for use as nano-scaled light-emitting diodes. The focus is on the presence of non-radiative emission in the form of dark line defects. We have performed the study using hyperspectral cathodoluminescence imaging. The platelets were grown on a template consisting of InGaN pyramids, flattened by chemical mechanical polishing. These templates are defect free, whereas the dark line defects are introduced in the lower barrier and tend to propagate through all the subsequent layers, as revealed by the imaging of different layers in the structure. We conclude that the dark line defects are caused by stacking mismatch boundaries introduced by multiple seeding and step bunching at the edges of the as-polished, dome shaped templates. To avoid these defects, we suggest that the starting material must be flat rather than dome shaped.

[Periodontitis - an often neglected risk factor for several other diseases]

Periodontitis is a chronic inflammatory disease that degrades dental supporting tissues, including the alveolar bone. The global prevalence is 19%, in Sweden it is 11%. Left untreated, periodontitis can cause loss of teeth. The initial clinical manifestations of periodontitis usually start between 35 and 45 years of age. The underlying pathological mechanism is an aberrant inflammatory response to the bacteria colonizing the gingival crevice. Periodontitis has been associated with several other diseases, most prominently diabetes. The relation between periodontitis and diabetes is bidirectional in the sense that diabetes increases the risk for periodontitis and vice versa. Periodontitis also increases the risk for cardiovascular disease and cancer.

[Diabetes and periodontitis - common, important but often neglected]

Diabetes and periodontitis are two global epidemics. There is a two-way relationship between diabetes and periodontitis. Diabetes increases the risk of periodontitis and periodontitis increases the risk for deteriorating glucose levels, having undetected diabetes, and for future diabetes. A recent Cochrane report summarized that there is moderate-certainty evidence that periodontal treatment improves glycaemic control in people with both periodontitis and diabetes. The recent PAROKRANK study found that undetected dysglycaemia was independently associated to both myocardial infarction and to periodontitis. To increase awareness of oral health in people with diabetes this article summarizes recent evidence.

Periodontitis in young individuals: Important factors for disease progression

AIM

To investigate the progression of periodontitis in young individuals and identify factors that contribute to progression rate and whether periodontitis stage and grade have an impact on disease progression.

MATERIALS AND METHODS

This retrospective cohort study was based on patients younger than 36 years at two periodontal clinics between 2003 and 2009. At least 10 years later, a clinical and radiographic examination was performed on 215 patients. The marginal bone loss between baseline and follow-up for the tooth with the most severe bone loss at follow-up was estimated by radiographic measurements. Linear regression analysis was used to investigate the influence of potential risk indicators on periodontitis progression.

RESULTS

Most patients (83%) were classified as periodontitis stage III at baseline. At follow-up, 70% of these patients remained in stage III. The frequency of patients with grade C decreased from 79% to 17% at follow-up. The median (Q25%; Q75%) of the longitudinal marginal bone loss was 0.5 mm (0.0; 2.0). High bleeding on probing (BOP) index at baseline, smoking and interruption of periodontal treatment were found to significantly increase longitudinal bone loss.

CONCLUSIONS

High levels of BOP at baseline, smoking and interruption of periodontal treatment increased the risk of marginal bone loss. The stage and grade at baseline had no significant impact on disease progression.

Access to novel cancer medicines in four countries in Central and Eastern Europe in relation to clinical benefit

BACKGROUND

Almost 100 novel cancer medicines have been approved in Europe over the last decade. Limited public health care resources in countries in Central and Eastern Europe (CEE) call for a prioritization of access to effective medicines. We investigated how both reimbursement status and waiting time to reimbursement correlate with the magnitude of clinical benefit provided by novel medicines in four selected countries (Czechia, Hungary, Poland, and Slovakia).

MATERIALS AND METHODS

A total of 124 indications of 51 cancer medicines with marketing authorization by the European Medicines Agency in 2011-2020 were included and followed up until 2022. Data on reimbursement status and waiting time to reimbursement (i.e. time from marketing authorization to national reimbursement approval) were collected for each country. Data were analyzed in relation to clinical benefit status (i.e. substantial versus nonsubstantial clinical benefit) of indications according to the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS).

RESULTS

The degree of reimbursement differed between countries with 64% of indications with reimbursement in Czechia, 40% in Hungary, 51% in Poland, and 19% in Slovakia. In all countries, a significantly greater proportion of indications with a substantial clinical benefit was reimbursed (P < 0.05). The median waiting time to reimbursement ranged from 27 months in Poland to 37 months in Hungary. No significant differences in waiting time in relation to clinical benefit were observed in any country (P = 0.25-0.84).

CONCLUSIONS

Cancer medicines with a substantial clinical benefit are more likely to be reimbursed in all four CEE countries. Waiting times to reimbursement are equally long for medicines with or without a substantial clinical benefit, indicating a lack of prioritization of fast access to medicines delivering a substantial benefit. Incorporation of the ESMO-MCBS in reimbursement assessments and decisions could aid in better utilization of limited resources to deliver more effective cancer care.

The Resolution of Periodontal Inflammation Promotes Changes in Cytokine Expression in the Intestine and Gingival Tissues of Aged Rats with DSS-Induced Colitis

Our research aimed to explore how resolving periodontal inflammation impacts cytokine expression in the colons of aged Wistar rats. Research studies involving animals have been conducted to investigate the two-way relationship between periodontitis and inflammatory bowel disease (IBD), where chronic inflammation in either the mouth or intestines can negatively affect the other. We allocated seventeen male Wistar rats aged between 8 and 11 months to one of four groups: (1) ligature-induced periodontitis (LIP) without the resolution of periodontal inflammation (RPI) (LIP; n = 4), (2) LIP + RPI (n = 4), (3) LIP + dextran-sulphate-sodium-induced colitis (DIC) without RPI (n = 4), and LIP + DIC + RPI (n = 5). We performed histopathological and immunological analyses on periodontal and intestinal tissues and analysed cytokine expressions using a Rat Cytokine 23-Plex Immunoassay. Our findings showed that animals with and without DIC who underwent RPI showed significantly lower levels of IL-2, IL-4, IL-5, IL-10, IL-13, IL-17, IL-18, and TNF-α in the intestine compared to those without treatment. The RPI effectively reduced the number of inflammatory cells in the lamina propria and restored the epithelial barrier in the intestine in animals with DIC. The resolution of periodontal inflammation significantly reduced the levels of pro-inflammatory cytokines and chemokines in the intestines of aged rats with and without DSS-induced colitis.

Higher expression of Th1/Th2-related cytokines in the intestine of Wistar rats with ligature-induced periodontitis

OBJECTIVE

This study aimed to investigate the impact of ligature-induced periodontitis (LIP) on histopathological and immunological outcomes in the colon of Wistar rats.

BACKGROUND

It has been repeatedly shown that inflammatory bowel disease (IBD) patients are at higher risk of developing periodontitis and presenting worse oral health than non-IBD patients. However, whether the chronic inflammatory process around teeth contributes to the pathophysiology of IBD needs to be further explored.

MATERIALS AND METHODS

Thirteen Wistar rats were allocated into LIP (n = 7) and controls (n = 6). Half of the colon was processed for histopathological analyses and immunohistochemical (CD45); the other half was homogenized for immunological analyses. Periodontal destruction was confirmed by measuring the distance from the cementum-enamel junction to the mandible's apical position of the mesial interproximal bone. The immunological analyses were performed with the Bio-Plex Th1/Th2 assay.

RESULTS

There was a significantly higher interproximal bone loss in LIP compared to controls. The LIP group showed a moderate infiltrate of inflammatory cells, predominantly mononucleated cells in the intestinal tissues. There was significantly higher expression of GM-CSF, IFN-γ, IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-10, IL-12 (p70), IL-13, and TNF-α in the intestinal tissues of LIP group compared to controls.

CONCLUSION

Ligature-induced periodontitis was associated with an overexpression of Th1/Th2-related cytokines in the colon of Wistar rats.

Colitis induced by dextran sulphate sodium causes histopathological and immunological changes in the periodontal tissues of Wistar rats

OBJECTIVE

This study investigated the impact of colitis induced by dextran sulphate sodium (DSS)-induced colitis (DIC) on histopathological and immunological outcomes in the periodontal tissues of Wistar rats.

BACKGROUND

Inflammatory bowel diseases (IBD) and periodontitis have been reported to present a bidirectional relationship. However, the inflammatory pathway that connects both diseases needs further investigation.

MATERIAL AND METHODS

Twenty-five male Wistar rats were allocated in four groups: unilateral ligature-induced periodontitis for 14 days: LIP (n = 7); dextran sulphate sodium-induced colitis only: DIC (n = 6); DIC + LIP (n = 6) and controls (n = 6). Digital images were obtained from the histological sections. In order to assess the attachment loss (AL), the linear distance between the cementoenamel junction (CEJ) and the alveolar bone crest was measured on the mesial root using histological photomicrography's ImageJ software. Immunological analyses of gingival tissues and plasma were performed by Bio-Plex Th1/Th2 Assay.

RESULTS

The DIC group showed inflammatory cells extending to the periodontal connective tissues, which contained significantly elevated expressions of IL-1α, IL-1β, IL-2, IL-6, IL-12, IL-13, GM-CSF, IFN-γ and TNF-α compared to controls. There was no significant difference in bone loss between controls and DIC. There were no significant histopathological differences between DIC + LIP and LIP. However, DIC + LIP presented a significantly lower IL-2 and IL-5 than the LIP group. There was no bone loss difference between LIP+DIC and LIP groups. DIC + LIP group presented significantly higher levels of GM-CSF in plasma.

CONCLUSION

DSS-induced colitis was associated with an overexpression of Th1/Th2- related cytokines in the gingival tissue.

Association of peptidoglycan recognition protein 1 to post-myocardial infarction and periodontal inflammation: A subgroup report from the PAROKRANK (Periodontal Disease and the Relation to Myocardial Infarction) study

BACKGROUND

Peptidoglycan recognition protein 1 (PGLYRP1) is an antimicrobial and proinflammatory innate immunity protein activated during infections. We aimed to investigate whether PGYLRP1 and associated molecules of the immune response in saliva is a cumulative outcome result of both MI and periodontal inflammation.

METHODS AND RESULTS

Two hundred patients with MI and another 200 matched non-MI controls were included. A full-mouthexamination was conducted to assess periodontal inflammation and collection of stimulated saliva was performed 6 to 10 weeks after the first MI. PGLYRP1, triggering receptor expressed on myeloid cells 1 (TREM-1), interleukin-1 beta (IL-1β) were analyzed by ELISA. Matrix metalloproteinase (MMP)-8 levels were determined by IFMA. Compared to controls, MI patients showed higher salivary PGLYRP1, but not TREM-1 levels. The difference in PGLYRP1 levels remained after adjustment for covariates. In MI patients, the PGLYRP1 levels positively correlated with BOP and PPD 4 to 5 mm. Among non-MI subjects, the levels of PGLYRP1 correlated positively and significantly with BOP and total PPD. Salivary PGLYRP1 concentrations also showed strong positive correlations with levels of TREM-1, IL-1β and MMP-8. In multivariate linear regression analysis, in MI patients, BOP and former smokingstatus displayed an association with salivary PGLYRP1 concentration.

CONCLUSION

MI patients showed higher salivary PGLYRP1 levels than healthy controls, also after adjusting for smoking, sex, age and periodontal health status. Salivary levels of PGLYRP1 may reflect the overall inflammatory burden to chronic bacterial exposure, possibly underpinning the observed associations between periodontitis and exposure with MI.

Periodontitis and cardiovascular outcome – a prospective follow-up of the PAROKRANK cohort

Background

There is an association between periodontitis (PD) and myocardial infarction (MI). Whether that is related to shared risk factors or it is causal is debated. The Periodontitis and Its Relation to Coronary Artery Disease (PAROKRANK) case-control study previously reported on an independent association between PD and a first MI.

Purpose

This follow-up of the PAROKRANK study tests the hypothesis that PD increases the risk for new cardiovascular (CV) events.

Methods

Between 2010–2014 805 patients (age &lt;75 years; females 19%) with a first MI and 805 controls without MI, matched for gender, age (mean 62±8 years) and living area underwent a CV and dental examination including panoramic x-ray. The PD was categorised in three grades: healthy (≥80% remaining alveolar bone height), moderate (79–66%) or severe (&lt;66%). The composite primary endpoint was the first of all-cause death, non-fatal MI or stroke, or severe heart failure until December 2018. The first of CV-death, non-fatal MI or stroke, or severe heart failure served as a secondary CV-endpoint. Data on outcomes were provided via linkage to the National Patient Registries and the Cause of Death Registry. Cumulative event rates, stratified by PD status at baseline in the combined cohort of cases and controls, were calculated using logistic regression and the Kaplan-Meier method.

Results

A total of 1587 participants with evaluated PD-status were followed for a mean of 6.2 (range 0.2–8.5) years. The total number of primary events and CV-events was 205 and 158 respectively. The number of deaths was 68. Baseline PD-status was healthy in 985 (mean age 60.4 years), moderate in 489 (mean age 65.1 years) and severe in 113 (mean age 64.3 years) participants. The figure presents the time to primary event by the three PD grades in the combined cohort (patients and controls). Time to the primary endpoint differed between the three PD grades (log-rank test 0.0148), however, significant only for patients (log-rank test patients vs. controls: 0.0382 vs. 0.608). Replacing the primary endpoint with the secondary CV-endpoint just changed the outcome slightly (log-rank 0.0976), possibly due to a low number of CV-deaths within the CV-event. Compared to participants without PD, the presence of PD at baseline was associated with the primary endpoint in the total cohort (Odds Ratio (OR): 1.49; 95% Confidence Interval (CI): 1.11–2.00) as well as the CV-endpoint (OR 1.42; 95% CI 1.02–1.98). PD was not associated with total mortality (OR 1.57; 95% CI 0.97–2.56).

Conclusion

In this up to 8-years follow up of the PAROKRANK cohort there was a graded increase in the risk for new CV-events by the presence of PD. This was in particular seen in the MI-patients. Together with the previous case-control based report from PAROKRANK, on an association between PD and a first MI, the findings during the follow-up supports the assumption that there may be a causal relationship between PD and CV-disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The PAROKRANK study was supported by grants from AFA Insurance, Swedish Heart-Lung Foundation, Swedish Research Council, Swedish Society of Medicine, Stockholm County Council (ALF project and Steering committee KI/SLL for odontological research), and The Baltic Child Foundation. Figure 1

Long term outcome after a first myocardial infarction

Background

Prognosis after a myocardial infarction (MI) have improved consistently over the last decades. In parallel, the incidence of cardiovascular (CV) events has been reduced and life expectancy in people free from CV disease improved.

Purpose

To explore the long-term mortality and burden of cardiovascular disease in patients after a first MI compared to matched controls in a contemporary setting.

Methods

The Swedish case-control study PAROKRANK recruited 805 patients &lt;75 years with a first MI and 805 age-, gender- and area-matched controls from 2010 to 2014. All participants were followed by means of registry-based information. The primary endpoint was the first of a composite of all-cause death, non-fatal MI, non-fatal stroke and heart failure hospitalization. Data on the outcomes were provided via linkage to the National Patient Registries and the Cause of Death Registry. Hazard Ratios (HR) for the first composite event were calculated by means of a Cox regression model, subsequently adjusted for smoking, education level and marital status at baseline. Event curves for the time-to-first event in patients and controls were computed by Kaplan-Meier curves and the two groups were compared by means of the log-rank test.

Results

Data from 804 patients and 800 controls (mean age in both groups 62 years; women 19%) were complete for an average period of 6.2 years (0.2–8.5 years). The total number of events was 211. Patients had a higher event rate than controls (log rank p&lt;0.0001). Unadjusted HR for the primary outcome was 2.08 (95% confidence interval (CI) 1.56–2.77) while the adjusted HR was 2.04 (95% CI 1.52–2.73). Mortality did not differ significantly between patients (n=38; 4.7%) and controls (n=35; 4.4%). In total, 82.5% of the patients and 91.3% of the controls were event-free during follow-up.

Conclusion

This long-term follow-up of a contemporary, nationwide case-control cohort illustrates that the likelihood for CV events is higher in patients with a first MI compared to their matched controls while mortality did not differ. The access to high quality of care and cardiac rehabilitation might explain the low rates of adverse outcomes.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): AFA Insurance, Swedish Heart-Lung Foundation, Swedish Research Council, Swedish Society of Medicine, Stockholm County Council (ALF project and Steering committee KI/SLL for odontological research), and The Baltic Child Foundation. Figure 1. Kaplan-Meier curves

Designing satisfying service encounters: website versus store touchpoints

This study investigated how touchpoints moderate the antecedents of customer satisfaction with service encounters by comparing online and in-store encounters. Construal level theory was used within the Touchpoint, Context, Qualities (TCQ) Framework (De Keyser et al., 2020) to integrate a comprehensive model of how touchpoints-websites or stores-influence the magnitude of customer responses to qualities of service encounters. A hierarchical linear model (HLM) was estimated using survey data describing the service encounters of 2.4 million customers with a global retailer. Online customers weighed cognitive and behavioral qualities more heavily than in-store customers, whereas they weighed emotional and sensorial qualities less heavily. Moreover, random effects in the HLM model indicated that each country and store would have unique clientele effects for specific qualities. Since each firm has limited resources, this research offers guidance on key qualities in designing satisfying service encounters for each touchpoint and how qualities should be standardized and customized in global omnichannel environments.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11747-021-00808-9.

Periodontitis is associated to increased systemic inflammation in postmyocardial infarction patients

Objective

Periodontitis has been independently associated to cardiovascular disease. However, the biological mechanisms underlying such association are still partially unknown. Thus, this study aimed to discover immunological clues accounting for the increased risk of myocardial infarction (MI) in patients having periodontitis.

Methods

We included 100 patients with a first MI, 50 with and 50 without severe periodontitis, and 100 age-matched, sex-matched and area-matched controls from the Periodontitis and Its Relation to Coronary Artery Disease Study. Participants underwent comprehensive clinical and laboratory examinations 6–10 weeks after the MI and plasma expression of 92 inflammation-related markers was assessed through proximity extension assay.

Results

Patients who had an MI displayed altered expression of CCL19, TNFRSF9 and LAP TGF-β1 in comparison with controls. TNFRSF9 correlated significantly with the amount of alveolar bone loss. MI patients with deep periodontal pockets showed increased white cell count and higher expression of FGF-21, HGF, OSM, CCL20 and IL-18R1 than patients without. White cell count correlated significantly with four of these proteins.

Conclusions

Collectively, our results indicate molecular markers that could be responsible for the increased systemic inflammatory activity in patients with MI with periodontitis.

From InGaN pyramids to micro-LEDs characterized by cathodoluminescence

We present a study of the optical properties of various steps in the process of fabricating micro light-emitting diodes (μ-LEDs) based on quantum wells embedded in micron-sized InGaN platelets. In this study, we focus on structures for red emission, but the technology is equally suitable for the less technologically challenging blue and green emitting μ-LEDs. The starting point is growth of an InGaN pyramid with a sub-micron sized hexagonal base. The pyramid is flattened to create a flat top c-facet for the subsequent InGaN quantum well growth. We compare two approaches, reshaping of the pyramid by high-temperature annealing; and by chemical mechanical polishing. Their merits are discussed. The flattened platelets are used as templates to grow low-strain single quantum wells in both heterostructures and full LEDs including n- and p-barriers on either side of the quantum well. The structures are investigated in terms of homogeneity in peak energy position and intensity using hyperspectral cathodoluminescence imaging. We observe that the main contribution to inhomogeneity is the growth of the initial pyramid, that exhibits regular, facet driven variations in the In incorporation.

Synthesis of Vertically Aligned ZnO Nanorods Using Sol-gel Seeding and Colloidal Lithography Patterning

Different ZnO nanostructures can be grown using low-cost chemical bath deposition. Although this technique is cost-efficient and flexible, the final structures are usually randomly oriented and hardly controllable in terms of homogeneity and surface density. In this work, we use colloidal lithography to pattern (100) silicon substrates to fully control the nanorods' morphology and density. Moreover, a sol-gel prepared ZnO seed layer was employed to compensate for the lattice mismatch between the silicon substrate and ZnO nanorods. The results show a successful growth of vertically aligned ZnO nanorods with controllable diameter and density in the designated openings in the patterned resist mask deposited on the seed layer. Our method can be used to fabricate optimized devices where vertically ordered ZnO nanorods of high crystalline quality are crucial for the device performance.

Periodontitis, assessed using periodontal treatment as a surrogate marker, has no association with a first myocardial infarction in a Swedish population

BACKGROUND

Periodontitis is suggested to be associated with a risk of cardiovascular events. Using periodontal treatment recorded in Swedish national registries as a surrogate marker, we aimed to investigate whether periodontitis was associated with a first myocardial infarction.

METHODS

This nationwide case-control study, with data from national registries, involved 51,880 individuals with a first myocardial infarction in 2011 to 2013 (index date) and 246,978 controls matched 5:1 for age, gender, and geographic area. Periodontal treatment in the 3 years preceding the index date was classified as (1) no dental treatment, (2) no periodontal treatment, (3) one or more supragingival curettages, or (4) one or more treatments with scaling/root planing and/or periodontal surgery. Annual frequencies of treatment with scaling/root planing and/or periodontal surgery were also calculated. In all analyses, conditional logistic regression analyses estimated ORs for myocardial infarction with 95% CIs, adjusted for matched variables, income, education, and diabetes.

RESULTS

Although fewer cases than controls received treatment with scaling/root planing and/or periodontal surgery (19.2% versus 19.8%, P < 0.001), annual frequencies for cases were higher. We found no association of scaling/root planing and/or periodontal surgery with a first myocardial infarction (OR = 1.02; 95% CI: 1.00, 1.05). We did observe a non-significant trend, however, between risk of a first myocardial infarction and a high frequency of scaling/root planing and/or periodontal surgery (OR 1.14; 95% CI: 1.00, 1.29).

CONCLUSION

In the contemporary Swedish nationwide setting, no association between a first myocardial infarction and periodontitis, assessed as periodontal treatment, was found.

Adjunctive Antiseptic Irrigation of Periodontal Pockets: Effects on Microbial and Cytokine Profiles

To evaluate the effect of adjunctive antiseptic irrigation of periodontal pockets on microbial and cytokine profiles. Fifty-nine patients with severe periodontitis were allocated to one of three groups for scaling and root planing facilitated with different adjunctive antiseptics: 1% polyhexamethyleneguanidine phosphate (PHMG-P) (n = 19), 0.2% chlorhexidine (CHX) (n = 21) or distilled water (n = 19). Gingival crevicular fluid and subgingival bacterial samples were collected at baseline, and at 2 weeks, and 1 and 4 months. The levels of interleukin (IL)-1β, IL-8, IL-10, and IL-17A, matrix metalloproteinase (MMP)-8, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum,Aggregatibacter actinomycetemcomitans, and Prevotella intermedia were determined. There were no intergroup differences in cytokine concentrations and bacterial counts at any follow-up, however, varying patterns were observed. In the PHMG-P and water groups IL-1β expression peaked at 2 weeks and then gradually declined. In all three groups, the dynamics of MMP-8 concentration were non-linear, increasing by 2 weeks and then declining to below baseline (p > 0.05). P. gingivalis and T. forsythia declined within the first month and increased thereafter, not regaining the baseline level. Adjunctive antiseptic treatment was associated with changes in biomarkers and bacterial counts in the course of the study. The effects of adjunctive antiseptic irrigation were limited in the applied protocol.

Hot-carrier separation in heterostructure nanowires observed by electron-beam induced current

The separation of hot carriers in semiconductors is of interest for applications such as thermovoltaic photodetection and third-generation photovoltaics. Semiconductor nanowires offer several potential advantages for effective hot-carrier separation such as: a high degree of control and flexibility in heterostructure-based band engineering, increased hot-carrier temperatures compared to bulk, and a geometry well suited for local control of light absorption. Indeed, InAs nanowires with a short InP energy barrier have been observed to produce electric power under global illumination, with an open-circuit voltage exceeding the Shockley-Queisser limit. To understand this behaviour in more detail, it is necessary to establish control over the precise location of electron-hole pair-generation in the nanowire. In this work we perform electron-beam induced current measurements with high spatial resolution, and demonstrate the role of the InP barrier in extracting energetic electrons.We interprete the results in terms of hot-carrier separation, and extract estimates of the hot carriers' mean free path.

Investigating the emerging COVID-19 research trends in the field of business and management: A bibliometric analysis approach

The COVID-19 pandemic has been labeled as a black swan event that caused a ripple effect on every aspect of human life. Despite the short time span of the pandemic-only four and half months so far-a rather large volume of research pertaining to COVID-19 has been published (107 articles indexed in Scopus and the Web of Science). This article presents the findings of a bibliometric study of COVID-19 literature in the business and management domain to identify current areas of research and propose a way forward. The analysis of the published literature identified four main research themes and 18 sub-themes. The findings and propositions of this study suggest that COVID-19 will be the catalyst of several long- and short-term policy changes and requires the theoretical and empirical attention of researchers. The offered propositions will act as a roadmap to potential research opportunities.

Fostering collaborative research for customer experience - Connecting academic and practitioner worlds

This editorial calls for greater use of academic-practitioner workshops to co-create value for academics, practitioners and wider network actors through promotion of research relevance and sharing of problems, ideas and data. It describes how one such workshop, the 2nd Academic-Practitioner Research with Impact Workshop focusing on the design and decision making for customer experience (CE), co-hosted in Manchester on 18th and 19th of June 2018 by Alliance Manchester Business School, the University of Manchester and Loughborough University's Centre for Service Management (CSM), was delivered. The key processes for success and issues to consider for future such events are discussed. The workshop resulted in 8 papers (six theoretical and two empirical). This Special Issue advances current understanding of CE through the research considering the role of technology (AI and big data) in CE research, atypical CE (vulnerability, deviance behaviours and service failure and recovery) and focusing on important organizational and B2B issues (business model innovation, and CE Management (CEM) in business markets).

Dislocation-Free and Atomically Flat GaN Hexagonal Microprisms for Device Applications

III-nitrides are considered the material of choice for light-emitting diodes (LEDs) and lasers in the visible to ultraviolet spectral range. The development is hampered by lattice and thermal mismatch between the nitride layers and the growth substrate leading to high dislocation densities. In order to overcome the issue, efforts have gone into selected area growth of nanowires (NWs), using their small footprint in the substrate to grow virtually dislocation-free material. Their geometry is defined by six tall side-facets and a pointed tip which limits the design of optoelectronic devices. Growth of dislocation-free and atomically smooth 3D hexagonal GaN micro-prisms with a flat, micrometer-sized top-surface is presented. These self-forming structures are suitable for optical devices such as low-loss optical cavities for high-efficiency LEDs. The structures are made by annealing GaN NWs with a thick radial shell, reforming them into hexagonal flat-top prisms with six equivalents either m- or s-facets depending on the initial heights of the top pyramid and m-facets of the NWs. This shape is kinetically controlled and the reformation can be explained with a phenomenological model based on Wulff construction that have been developed. It is expected that the results will inspire further research into micron-sized III-nitride-based devices.

Cathodoluminescence visualisation of local thickness variations of GaAs/AlGaAs quantum-well tubes on nanowires

We present spatially and spectrally resolved emission from nanowires with a thin radial layer of GaAs embedded in AlGaAs barriers, grown radially around taper-free GaAs cores. The GaAs layers are thin enough to show quantization, and are quantum wells. Due to their shape, they are referred to as quantum well tubes (QWTs). We have investigated three different nominal QWT thicknesses: 1.5, 2.0, and 6.0 nm. They all show average emission spectra from the QWT with an energy spread corresponding to a thickness variation of ±30%. We observe no thickness gradient along the length of the nanowires. Individual NWs show a number of peaks, corresponding to different QW thicknesses. Apart from the thinnest QWT, the integrated emission from the QWTs shows homogeneous emission intensity along the NW. The thinnest QWTs show patchy emission patterns due to the incomplete coverage of the QWT. We observe a few NWs with larger diameters. The QWTs in these NWs show spatially resolved variations across the NW. An increase in the local thickness of the QWT at the corners blocks the diffusion of carriers from facet to facet, thereby enabling us to visualise the thickness variations of the radial quantum wells.

Realization of Ultrahigh Quality InGaN Platelets to be Used as Relaxed Templates for Red Micro-LEDs

In this work, arrays of predominantly relaxed InGaN platelets with indium contents of up to 18%, free from dislocations and offering a smooth top c-plane, are presented. The InGaN platelets are grown by metal-organic vapor phase epitaxy on a dome-like InGaN surface formed by chemical mechanical polishing of InGaN pyramids defined by 6 equivalent {101̅1} planes. The dome-like surface is flattened during growth, through the formation of bunched steps, which are terminated when reaching the inclined {101̅1} planes. The continued growth takes place on the flattened top c-plane with single bilayer surface steps initiated at the six corners between the c-plane and the inclined {101̅1} planes, leading to the formation of high-quality InGaN layers. The top c-plane of the as-formed InGaN platelets can be used as a high-quality template for red micro light-emitting diodes.

Neuroscience in service research: an overview and discussion of its possibilities

Purpose

The purpose of this paper is to discuss recent developments in neuroscientific methods and demonstrate its potential for the service field. This work is a call to action for more service researchers to adopt promising and increasingly accessible neuro-tools that allow the service field to benefit from neuroscience theories and insights.

Design/methodology/approach

The paper synthesizes key literature from a variety of domains (e.g. neuroscience, consumer neuroscience and organizational neuroscience) to provide an in-depth background to start applying neuro-tools. Specifically, this paper outlines the most important neuro-tools today and discusses their theoretical and empirical value.

Findings

To date, the use of neuro-tools in the service field is limited. This is surprising given the great potential they hold to advance service research. To stimulate the use of neuro-tools in the service area, the authors provide a roadmap to enable neuroscientific service studies and conclude with a discussion on promising areas (e.g. service experience and servicescape) ripe for neuroscientific input.

Originality/value

The paper offers service researchers a starting point to understand the potential benefits of adopting the neuroscientific method and shows their complementarity with traditional service research methods like surveys, experiments and qualitative research. In addition, this paper may also help reviewers and editors to better assess the quality of neuro-studies in service.

Associations among Periodontitis, Calcified Carotid Artery Atheromas, and Risk of Myocardial Infarction

Cardiovascular disease is a common cause of morbidity and premature mortality. Cardiovascular disease can be prevented when risk factors are identified early. Calcified carotid artery atheromas (CCAAs), detected in panoramic radiographs, and periodontitis have both been associated with increased risk of cardiovascular disease. This case-control study aimed to 1) investigate associations between periodontitis and CCAA detected in panoramic radiographs and 2) determine the risk of future myocardial infarctions due to CCAA combined with periodontitis. We evaluated 1,482 participants (738 cases and 744 controls) with periodontitis and CCAAs recruited from the PAROKRANK study (Periodontitis and Its Relation to Coronary Artery Disease). Participants were examined with panoramic radiographs, including the carotid regions. Associations between myocardial infarction and periodontitis combined with CCAA were evaluated in 696 cases and 696 age-, sex-, and residential area–matched controls. Periodontitis was evaluated radiographically (as degree of bone loss) and with a clinical periodontal disease index score (from clinical and radiographic assessments). We found associations between CCAA and clinical periodontal disease index score among cases (odds ratio [OR], 1.51; 95% CI, 1.09 to 2.10; P = 0.02) and controls (OR, 1.70; 95% CI, 1.22 to 2.38; P < 0.01), although not between CCAA and the degree of bone loss. In a multivariable model, myocardial infarction was associated with CCAA combined with periodontitis, as assessed by degree of bone loss (OR, 1.75; 95% CI, 1.11 to 2.74; P = 0.01). When the cohort was stratified by sex, only men showed a significant association between myocardial infarction and CCAA combined with periodontitis. Participants with clinically diagnosed periodontitis exhibited CCAA in panoramic radiographs more often than those without periodontitis, irrespective of the presence of a recent myocardial infarction. Participants with combined periodontitis and CCAA had a higher risk of having had myocardial infarction as compared with participants with either condition alone. These findings implied that patients in dental care might benefit from dentists assessing panoramic radiographs for CCAA—particularly, patients with periodontitis who have not received any preventive measures for cardiovascular disease.

Undetected Dysglycemia Is an Important Risk Factor for Two Common Diseases, Myocardial Infarction and Periodontitis: A Report From the PAROKRANK Study

OBJECTIVE

Information on the relationship among dysglycemia (prediabetes or diabetes), myocardial infarction (MI), and periodontitis (PD) is limited. This study tests the hypothesis that undetected dysglycemia is associated with both conditions.

RESEARCH DESIGN AND METHODS

The PAROKRANK (Periodontitis and Its Relation to Coronary Artery Disease) study included 805 patients with a first MI and 805 matched control subjects. All participants without diabetes (91%) were examined with an oral glucose tolerance test. Abnormal glucose tolerance (AGT) (impaired glucose tolerance or diabetes) was categorized according to the World Health Organization. Periodontal status was categorized from dental X-rays as healthy (≥80% remaining alveolar bone height), moderate (79-66%), or severe (<66%) PD. Odds ratios (ORs) and 95% CIs were calculated by logistic regression and were adjusted for age, sex, smoking, education, marital status, and explored associated risks of dysglycemia to PD and MI, respectively.

RESULTS

AGT was more common in patients than in control subjects (32% vs. 19%; P < 0.001) and was associated with MI (OR 2.03; 95% CI 1.58-2.60). Undetected diabetes was associated with severe PD (2.50; 1.36-4.63) and more strongly in patients (2.35; 1.15-4.80) than in control subjects (1.80; 0.48-6.78), but not when categorized as AGT (total cohort: 1.07; 0.67-1.72). Severe PD was most frequent in subjects with undetected diabetes, and reversely undetected diabetes was most frequent in patients with severe PD.

CONCLUSIONS

In this large case-control study previously undetected dysglycemia was independently associated to both MI and severe PD. In principal, it doubled the risk of a first MI and of severe PD. This supports the hypothesis that dysglycemia drives two common diseases, MI and PD.

Highly Strained III-V-V Coaxial Nanowire Quantum Wells with Strong Carrier Confinement

Coaxial quantum wells (QWs) are ideal candidates for nanowire (NW) lasers, providing strong carrier confinement and allowing close matching of the cavity mode and gain medium. We report a detailed structural and optical study and the observation of lasing for a mixed group-V GaAsP NW with GaAs QWs. This system offers a number of potential advantages in comparison to previously studied common group-V structures ( e. g., AlGaAs/GaAs) including highly strained binary GaAs QWs, the absence of a lower band gap core region, and deep carrier potential wells. Despite the large lattice mismatch (∼1.7%), it is possible to grow defect-free GaAs coaxial QWs with high optical quality. The large band gap difference results in strong carrier confinement, and the ability to apply a high degree of compressive strain to the GaAs QWs is also expected to be beneficial for laser performance. For a non-fully optimized structure containing three QWs, we achieve low-temperature lasing with a low external (internal) threshold of 20 (0.9) μJ/cm²/pulse. In addition, a very narrow lasing line width of ∼0.15 nm is observed. These results extend the NW laser structure to coaxial III-V-V QWs, which are highly suitable as the platform for NW emitters.

InGaN Platelets: Synthesis and Applications toward Green and Red Light-Emitting Diodes

In this work, we present a method to synthesize arrays of hexagonal InGaN submicrometer platelets with a top c-plane area having an extension of a few hundred nanometers by selective area metal-organic vapor-phase epitaxy. The InGaN platelets were made by in situ annealing of InGaN pyramids, whereby InGaN from the pyramid apex was thermally etched away, leaving a c-plane surface, while the inclined {101̅1} planes of the pyramids were intact. The as-formed c-planes, which are rough with islands of a few tens of nanometers, can be flattened with InGaN regrowth, showing single bilayer steps and high-quality optical properties (full width at half-maximum of photoluminescence at room temperature: 107 meV for In_0.09Ga_0.91N and 151 meV for In_0.18Ga_0.82N). Such platelets offer surfaces having relaxed lattice constants, thus enabling shifting the quantum well emission from blue (as when grown on GaN) to green and red. For single InGaN quantum wells grown on the c-plane of such InGaN platelets, a sharp interface between the quantum well and the barriers was observed. The emission energy from the quantum well, grown under the same conditions, was shifted from 2.17 eV on In_0.09Ga_0.91N platelets to 1.95 eV on In_0.18Ga_0.82N platelets as a result of a thicker quantum well and a reduced indium pulling effect on In_0.18Ga_0.82N platelets. On the basis of this method, prototype light-emitting diodes were demonstrated with green emission on In_0.09Ga_0.91N platelets and red emission on In_0.18Ga_0.82N platelets.

Attitudes and lifestyle factors in relation to oral health and dental care in Sweden: a cross-sectional study

OBJECTIVE

The aim of the present study was to investigate attitudes to and perceptions of dental treatment and costs, self-assessed personal oral health status and dental self-care in an adult Swedish population, with special reference to potential associations between these factors and periodontal status.

MATERIAL AND METHODS

The study population comprised 1577 subjects who had undergone radiographic dental examination. The subjects were grouped by severity of periodontitis, based on extent of bone loss, as none, mild/moderate or severe. Subjects answered a questionnaire about socioeconomic factors, oral care habits and attitudes to dental treatment. Other questions covered medical history, smoking and other life style factors. Associations were tested using the Chi-squared test and a logistic regression model.

RESULTS

Compared to subjects with no periodontitis, those with mild/moderate or severe periodontitis were less likely to afford (p < .001), more often refrained from treatment due to costs (p < .001) and in the past year had experienced dental problems for which they had not sought treatment (p < .001). They also reported more anxiety in relation to dental appointments (p = .001). Regarding caries prevention, the severe periodontitis group used least fluoride products (p = .002).

CONCLUSIONS

Swedish adults regard their oral health as important, those with periodontitis have a more negative perception of their oral health and are less prone to seek help. These discouraging findings suggest the need for targeted measures, which focus on improving the care of this group of patients.

Polyhexamethylene guanidine phosphate irrigation as an adjunctive to scaling and root planing in the treatment of chronic periodontitis

OBJECTIVE

To evaluate the efficacy of adjunctive polyhexamethylene guanidine (PHMG) phosphate irrigation in periodontal treatment.

MATERIALS AND METHODS

The subjects comprised 59 patients with severe chronic periodontitis. Plaque index, bleeding on probing (BOP) and pocket probing depths (PPD) were recorded. The subjects were randomly allocated to one of three groups for scaling and root planning, with different adjunctive irrigants: 1% PHMG phosphate (19 subjects), 0.2% chlorhexidine (21 subjects) and distilled water (19 subjects). Patients were recalled after two weeks, one month and then after 4, 6 and 12 months.

RESULTS

In all groups, treatment resulted in considerable improvement of the observed clinical parameters. There were no intergroup differences in plaque index and BOP at any time point, but significant differences in PPD at one, four and six months. By the end of the study no intergroup differences in PPDs persisted. While post study surgical treatment needs decreased in all three groups, no intergroup differences were observed in the number of deep periodontal pockets.

CONCLUSIONS

Irrigation with PHMG phosphate significantly reduces PPDs in the short-term, but has no significant long-term effect on the mean pocket depth.

Leaky gut biomarkers in depression and suicidal behavior

OBJECTIVE

Inflammation is associated with major depressive disorder (MDD) and suicidal behavior. According to the 'leaky gut hypothesis', increased intestinal permeability may contribute to this relationship via bacterial translocation across enterocytes. We measured plasma levels of gut permeability markers, in patients with a recent suicide attempt (rSA), MDD subjects with no history of a suicide attempt (nsMDD), and healthy controls (HC), and related these markers to symptom severity and inflammation.

METHOD

We enrolled rSA (n = 54), nsMDD (n = 13), and HC (n = 17). Zonulin, intestinal fatty acid binding protein (I-FABP), soluble CD14, and interleukin-6 (IL-6) were quantified in plasma. Montgomery-Åsberg Depression Rating Scale (MADRS) and Suicide Assessment Scale (SUAS) were used for symptom assessments.

RESULTS

The rSA group displayed higher I-FABP and lower zonulin levels compared with both the nsMDD and the HC groups (all P < 0.001). IL-6 correlated positively with I-FABP (r = 0.24, P < 0.05) and negatively with zonulin (r = -0.25, P < 0.05). In all subjects, I-FABP levels correlated positively with MADRS (r = 0.25, P < 0.05) and SUAS scores (r = 0.38, P < 0.001), and the latter correlation was significant also in the nsMDD group (r = 0.60, P < 0.05).

CONCLUSION

The 'leaky gut hypothesis' may improve our understanding of the link between inflammation and suicidal behavior. These findings should be considered preliminary until replicated in larger cohorts.

Structural Changes in a Single GaN Nanowire under Applied Voltage Bias

GaN nanowires (NWs) are promising building blocks for future optoelectronic devices and nanoelectronics. They exhibit stronger piezoelectric properties than bulk GaN. This phenomena may be crucial for applications of NWs and makes their study highly important. We report on an investigation of the structure evolution of a single GaN NW under an applied voltage bias along polar [0001] crystallographic direction until its mechanical break. The structural changes were investigated using coherent X-ray Bragg diffraction. The three-dimensional (3D) intensity distributions of the NWs without metal contacts, with contacts, and under applied voltage bias in opposite polar directions were analyzed. Coherent X-ray Bragg diffraction revealed the presence of significant bending of the NWs already after metal contacts deposition, which was increased at applied voltage bias. Employing analytical simulations based on elasticity theory and a finite element method (FEM) approach, we developed a 3D model of the NW bending under applied voltage. From this model and our experimental data, we determined the piezoelectric constant of the GaN NW to be about 7.7 pm/V in [0001] crystallographic direction. The ultimate tensile strength of the GaN NW was obtained to be about 1.22 GPa. Our work demonstrates the power of in operando X-ray structural studies of single NWs for their effective design and implementation with desired functional properties.

MMP-12 and S100s in saliva reflect different aspects of periodontal inflammation

Matrix metalloproteinase (MMP)-12, S100A8/A9, and S100A12 are involved in innate immune responses. We addressed whether different aspects of oral health and non-disease-related covariates influence their levels in saliva. 436 participants were clinically examined, completed a health questionnaire, and provided stimulated saliva. Salivary levels of MMP-12, S100A8/A9, and S100A12 were determined by enzyme-linked immunosorbent assays. Lower MMP-12 levels were observed in individuals 40-64 years old (yo) compared to < 40 yo, and higher S100A8/A9 levels were found in individuals > 64 yo compared to 40-64 yo. Smokers exhibited lower MMP-12 and S100A12 levels compared to non-smokers. All three proteins were elevated in individuals with bleeding on probing (BOP) > 20% compared to those with BOP ≤ 20%, and the S100A8/A9 levels were higher in individuals having ≥ 10% gingival pocket depths (PPD) ≥ 4 mm compared to the ones with shallow pockets < 4 mm. The extent of alveolar bone loss or presence of manifest caries did not alter any of the markers. MMP-12, S100A8/A9, and S100A12 levels were higher in participants with high periodontal inflammatory burden. All three proteins correlated positively to BOP, PPD, and to several inflammatory mediators. The explanatory variables for MMP-12 in saliva were age, smoking, presence of any tumor, and percentage of PPD ≥ 4 mm. The determinant of salivary S100A8/A9 was percentage of BOP, while S100A12 levels were associated with percentage of BOP and presence of any tumor. Taken together, MMP-12 and the S100/calgranulin levels in saliva reflect different aspects of periodontal inflammation. Smoking and age should be taken into account in further investigation of these proteins as biomarker candidates of periodontal disease.

Single-Mode Near-Infrared Lasing in a GaAsSb-Based Nanowire Superlattice at Room Temperature

Semiconductor nanowire lasers can produce guided coherent light emission with miniaturized geometry, bringing about new possibilities for a variety of applications including nanophotonic circuits, optical sensing, and on-chip and chip-to-chip optical communications. Here, we report on the realization of single-mode and room-temperature lasing from 890 to 990 nm, utilizing a novel design of single nanowires with GaAsSb-based multiple axial superlattices as a gain medium under optical pumping. The control of lasing wavelength via compositional tuning with excellent room-temperature lasing performance is shown to result from the unique nanowire structure with efficient gain material, which delivers a low lasing threshold of ∼6 kW/cm² (75 μJ/cm² per pulse), a lasing quality factor as high as 1250, and a high characteristic temperature of ∼129 K. These results present a major advancement for the design and synthesis of nanowire laser structures, which can pave the way toward future nanoscale integrated optoelectronic systems with superior performance.

Invasive Dental Treatment and Risk for a First Myocardial Infarction

Invasive dental treatment is suggested to be associated with an increased risk for the development of cardiovascular events. We tested the hypothesis that the incidence of a first myocardial infarction (MI) within 4 wk after invasive dental treatments is increased. A registry-based case-control study within nationwide health care and population registries in Sweden was performed. The case patients included 51,880 individuals with a first fatal or nonfatal MI between January 2011 and December 2013. For each case, 5 control subjects, free from prior MI and matched for age, sex, and geographic area of residence, were randomly selected from the national population registry through risk set sampling with replacement, resulting in 246,978 control subjects. Information on dental treatments was obtained from the Dental Health Register, and the procedures were categorized into invasive dental treatments or other dental treatments. Conditional logistic regression was used to estimate odds ratios (ORs) for MI with corresponding 95% confidence intervals (CIs). In addition to the matching variables, adjustments were made for the following confounders: diabetes, previous cardiovascular disease (CVD), CVD drug treatment, education, and income. The mean age for case patients and controls subjects was 72.6 ± 13.0 y and 72.3 ± 13.0 y, respectively. Case patients more often had previous CVD (49% vs. 23%; P < 0.001) and diabetes (19% vs. 11%; P < 0.001) and received more treatment with CVD drugs (68% vs. 56%; P < 0.001) than control subjects. There was no association between invasive dental treatments during the 4 wk preceding the MI index date (crude OR = 0.99; 95% CI, 0.92 to 1.06; adjusted for confounders OR = 0.98; 95% CI, 0.91 to 1.06). This study did not support the hypothesis of an increased incidence of MI after recent invasive dental treatment.

Severe Periodontitis Is Associated with Myocardial Infarction in Females

The aim of the present study was to test the hypothesis that there is a sex difference in the association between periodontitis (PD) and a first myocardial infarction (MI). The analysis in the case-control study was based on 785 patients (147 females and 638 males) with a first MI and 792 matched controls (147 females and 645 males), screened for cardiovascular risk factors and subjected to a panoramic dental X-ray. Periodontal status was defined by alveolar bone loss and diagnosed as no PD (≥80% remaining alveolar bone), mild to moderate PD (66% to 79%), or severe PD (<66%). Logistic regression was used when analyzing PD as a risk factor for MI, adjusting for age, smoking, diabetes, education, and marital status. The mean age was 64 ± 7 y for females and 62 ± 8 y for males. Severe PD was more common in female patients than female controls (14 vs. 4%, P = 0.005), with an increased risk for severe PD among female patients with a first MI (odds ratio [OR] = 3.92, 95% confidence interval [CI] =1.53 to 10.00, P = 0.005), which remained (OR = 3.72, 95% CI = 1.24 to 11.16, P = 0.005) after adjustments. Male patients had more severe PD (7% vs. 4%; P = 0.005) than male controls and an increased risk for severe PD (OR = 1.88, 95% CI = 1.14 to 3.11, P = 0.005), but this association did not remain following adjustment (OR = 1.67, 95% CI = 0.97 to 2.84, NS). Severe PD was associated with MI in both females and males. After adjustments for relevant confounders, this association did, however, remain only in females. These data underline the importance of considering poor dental health when evaluating cardiovascular risk, especially in females.

Salivary microbial profiles in relation to age, periodontal, and systemic diseases

Background

Analysis of saliva is emerging as a promising tool to diagnose and monitor diseases which makes determination of the salivary microbial profile in different scenarios essential.

Objective

To evaluate the effects of age, periodontal disease, sex, smoking, and medical conditions on the salivary microbial profile.

Design

A randomly selected sample of 441 individuals was enrolled (51% women; mean age 48.5±16.8). Participants answered a health questionnaire and underwent an oral examination. Stimulated saliva was collected and the counts of 41 bacteria were determined by checkerboard DNA-DNA hybridization.

Results

Elderly participants (> 64 years old) presented a significant increase in 24 out of 41 bacterial species compared to adults (≤ 64 years old). Eubacterium nodatum, Porphyromonas gingivalis, and Tannerella forsythia were significantly higher in participants with generalized bone loss compared to without. Males and non-smokers had higher bacteria counts in saliva. Individuals having mental disorders or muscle and joint diseases showed significantly altered microbial profiles whereas small or no differences were found for subjects with high blood pressure, heart disease, previous heart surgery, bowel disease, tumors, or diabetes.

Conclusion

Age, periodontal status, sex, smoking, and certain medical conditions namely, mental disorders and muscle and joint diseases, might affect the microbial profile in saliva.

Fluctuating potentials in GaAs:Si nanowires: critical reduction of the influence of polytypism on the electronic structure

In this work, the effects of Si doping in GaAs nanowires (NWs) grown on GaAs (111)B by molecular beam epitaxy with different Si doping levels (nominal free carrier concentrations of 1 × 10¹⁶, 8 × 10¹⁶, 1 × 10¹⁸ and 5 × 10¹⁸ cm^-3) are deeply investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), grazing incidence X-ray diffraction (GID), photoluminescence (PL) and cathadoluminescence (CL). TEM results reveal a mixture of wurtzite (WZ) and zinc-blende (ZB) segments along the NW axis independently of the Si doping levels. GID measurements suggest a slight increase of the ZB fraction with the Si doping. Low temperature PL and CL spectra exhibit sharp lines in the energy range 1.41-1.48 eV, for the samples with lower Si doping levels. However, the emission intensity increases and is accompanied by a clear broadening of the observed lines for the samples with higher Si doping levels. The staggered type-II band alignment only determines the optical properties of the lower doping levels in GaAs:Si NWs. For the higher Si doping levels, the electronic energy level structure of the NWs is determined by electrostatic fluctuating potentials intimately related to the amphoteric behavior of the Si dopant in GaAs. For the heavily doped NWs, the estimated depth of the potential wells is ∼96-117 meV. Our results reveal that the occurrence of the fluctuating potentials is not dependent on the crystalline phase and shows that the limitation imposed by the polytypism can be overcome.

Defect-induced infrared electroluminescence from radial GaInP/AlGaInP quantum well nanowire array light- emitting diodes

Radial GaInP/AlGaInP nanowire array light-emitting diodes (LEDs) are promising candidates for novel high-efficiency solid state lighting due to their potentially large strain-free active emission volumes compared to planar LEDs. Moreover, by proper tuning of the diameter of the nanowires, the fraction of emitted light extracted can be significantly enhanced compared to that of planar LEDs. Reports so far on radial growth of nanowire LED structures, however, still point to significant challenges related to obtaining defect-free radial heterostructures. In this work, we present evidence of optically active growth-induced defects in a fairly broad energy range in vertically processed radial GaInP/AlGaInP quantum well nanowire array LEDs using a variety of complementary experimental techniques. In particular, we demonstrate strong infrared electroluminescence in a spectral range centred around 1 eV (1.2 μm) in addition to the expected red light emission from the quantum well. Spatially resolved cathodoluminescence studies reveal a patchy red light emission with clear spectral features along the NWs, most likely induced by variations in QW thickness, composition and barriers. Dark areas are attributed to infrared emission generated by competing defect-assisted radiative transitions, or to trapping mechanisms involving non-radiative recombination processes. Possible origins of the defects are discussed.

Effects of polyhexamethylene guanidine phosphate on human gingival fibroblasts

OBJECTIVE

Polyhexamethylene guanidine phosphate (PHMG-P) was compared to chlorhexidine (CHX) in order to determine potential cytotoxic and immune-modulatory effects on human gingival fibroblasts.

MATERIALS AND METHODS

Cytotoxic effects of PHMG-P and CHX on human gingival fibroblasts were assessed using cell viability assay at various time points and concentrations. The effects of PHMG-P and CHX on the secretion of prostaglandin (PG) E₂, interleukin (IL)-6, IL-8 and matrix metalloproteinase (MMP)-1 by non-stimulated or IL-1β stimulated fibroblasts were evaluated by enzyme-linked immunosorbent assays.

RESULTS

PHMG-P concentration 0.00009% led to the total loss of fibroblast viability within 24 h, whereas inhibition of fibroblast viability by CHX occurred at significantly higher concentrations of 0.0009% (p < .001). Short-term exposure to 0.005% PHMG-P led to loss of fibroblast viability after 5 min, whilst cells exposed to 0.005% CHX survived 30 min of treatment (p < .001). IL-1β stimulation induced an inflammatory response with a significant increase in the secretion of PGE₂, IL-6, IL-8 and MMP-1. Treatment of IL-1β stimulated fibroblasts in combination with PHMG-P or CHX at concentrations of 0.000045 or 0.0.00009% resulted in significantly decreased PGE₂, IL-6, IL-8 and MMP-1 levels. PHMG-P or CHX alone did not affect the baseline secretion of PGE₂, IL-6, IL-8 or MMP-1 by gingival fibroblasts.

CONCLUSIONS

Cytotoxic effects on gingival fibroblasts were triggered by both PHMG-P and CHX at concentrations below those used in clinical practice. The tested antiseptics did not cause inflammation and reduced IL-1β-induced secretion of inflammatory mediators and collagenase by gingival fibroblasts, which suggests anti-inflammatory properties.

Colony stimulating factor-1 in saliva in relation to age, smoking, and oral and systemic diseases

Colony stimulating factor (CSF)-1 is a growth factor that stimulates the survival, proliferation and differentiation of mononuclear phagocytes, which has been implicated in several inflammatory diseases. This study evaluated the possible influence of age, sex, smoking, periodontitis, caries, and several systemic conditions on salivary levels of CSF-1. Four-hundred and forty-one individuals were enrolled in this study. All participants answered a health questionnaire and underwent a comprehensive oral examination. Stimulated saliva was collected and CSF-1 levels were analysed by enzyme-linked immunosorbent assay. Salivary levels of CSF-1 were significantly increased in participants over 64 years old and in non-smoking individuals, whereas no difference was observed between men and women. Individuals having periodontitis and manifest caries had significantly higher levels of CSF-1. Participants with muscle and joint disease exhibited increased CSF-1 levels as compared to those without. Age, smoking, percentage of pockets ≥4 mm, number of manifest caries lesions, and presence of tumor were associated with CSF-1 levels. Salivary levels of CSF-1 are associated with age, smoking, periodontitis, manifest caries, and the presence of muscle and joint diseases and tumors. CSF-1 might be a promising biomarker candidate in saliva of both local and systemic conditions that needs further investigation.

Saliva and plasma levels of cardiac-related biomarkers in post-myocardial infarction patients

AIM

To relate cardiac biomarkers, such as cystatin C and growth differentiation factor-15 (GDF-15) in saliva to myocardial infarction (MI) and to periodontal status, and to investigate the relation between salivary and plasma cardiac biomarkers.

MATERIALS AND METHODS

Two hundred patients with MI admitted to coronary care units and 200 matched controls without MI were included. Dental examination and collection of blood and saliva samples was performed 6-10 weeks after the MI for patients and in close proximity thereafter for controls. Analysing methods: ARCHITECT i4000SR, Immulite 2000 XPi or ELISA.

RESULTS

The mean age was 62 ± 8 years and 84% were male. Total probing pocket depth, fibrinogen, white blood cell counts and HbA1c were higher in patients than controls. GDF-15 levels correlated with most of the included clinical variables in both study groups. No correlation was found between plasma and saliva levels of cystatin C or GDF-15.

CONCLUSION

Salivary cystatin C and GDF-15 could not differentiate between MI patients and controls.

Room-temperature InP/InAsP Quantum Discs-in-Nanowire Infrared Photodetectors

The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication, and optoelectronic properties of infrared photodetectors comprising four million n⁺-i-n⁺ InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in the i-segment. By Zn compensation of the residual n-dopants in the i-segment, the room-temperature dark current is strongly suppressed to a level of pA/NW at 1 V bias. The low dark current is manifested in the spectrally resolved photocurrent measurements, which reveal strong photocurrent contributions from the InAsP quantum discs at room temperature with a threshold wavelength of about 2.0 μm and a bias-tunable responsivity reaching 7 A/W@1.38 μm at 2 V bias. Two different processing schemes were implemented to study the effects of radial self-gating in the nanowires induced by the nanowire/SiO_x/ITO wrap-gate geometry. Summarized, our results show that properly designed axial InP/InAsP nanowire heterostructures are promising candidates for broadband photodetectors.