Search Results (21)

Objective: This study aimed to assess COVID-19 vaccine effectiveness against death (VE), controlling for healthy vaccinee bias. Methods: We link all adult deaths through year-end 2022 in the State of Indiana, U.S.A., to vaccination records and identify which deceased received primary vaccination (measured as either one or two initial doses) and which received one or two booster doses. We measure COVID-19 mortality with the COVID Excess Mortality Percentage (CEMP). CEMP is calculated, for a group defined by various characteristics (age, sex, time period), as COVID-19 deaths divided by non-COVID natural deaths. The CEMP outcome measure accounts for healthy vaccinee bias by using non-COVID natural mortality to control for differences in population health. Results: We find a large healthy vaccinee bias. Controlling for this bias, we find substantial VE for primary vaccination and the first booster dose during the first five vaccine-available calendar quarters, from 1Q2021 through 1Q2022 (end of Omicron infection wave). However, over 2Q–4Q2022, we find no evidence for primary-vaccination VE, and find moderate but statistically insignificant booster VE, which largely wanes by 4Q2022. Conclusions: It is known that by 2Q2022, most people had natural immunity from prior COVID-19 infection. Thus, our results for 2Q–4Q2022 largely reflect comparing hybrid (infection plus vaccination) immunity to infection-only immunity. In this period, we find negligible mortality benefit from primary vaccination, and moderate but waning benefit from a booster dose. Policy Implications: Controlling for healthy vaccinee bias is crucial when estimating VE. We found limited VE against COVID-19 mortality over 2Q–4Q2022, but lacked data for more recent periods. Full article

The increasing atmospheric CO₂ concentration is one of the major environmental challenges, necessitating not only emission reduction but also effective carbon utilization. Non-thermal plasma-catalytic CO₂ conversion offers an efficient pathway under mild conditions by synergistically combining plasma activation with catalytic surface reactions. In this study, mesoporous ceria catalysts were synthesized by different methods and characterized using N₂ adsorption–desorption, SEM, XRD, XPS, CO₂-TPD, and XRF techniques. The materials exhibited distinct textural and electronic properties, including variations in surface area, pore structure, and basicity. Plasma-catalytic CO₂ dissociation experiments were conducted in a dielectric barrier discharge reactor at near-room temperature. Among the synthesized catalysts, Ce(mp)-4 demonstrated the highest CO₂ conversion of 32.3% at a 5 kV input voltage and superior energy efficiency, which can be attributed to its meso-macroporous structure that promotes microdischarge formation and enhances CO₂ adsorption–desorption dynamics. CO was the only product obtained, with near-100% selectivity. Catalyst stability testing showed no deactivation while spent catalyst characterization indicated carbon-containing species. The findings in this study highlight the critical role of tailored pore structure and basic-site distribution in optimizing plasma-catalytic CO₂ dissociation performance, offering a promising strategy for energy-efficient CO₂ utilization. Full article

Objective: Secretory factors, termed the secretome, in the conditioned medium (CM) from dental mesenchymal stem cells (MSCs) have shown anti-inflammatory, anti-apoptotic, and tissue regenerative potential. This cell-free product could be further developed by preconditioning cells with various biochemical agents, which lead to a change in secretome and CM profiles. Among the favorable candidates for CM production, metformin as an anti-diabetic medication is currently considered a potential agent for dental hard tissue and periodontal regeneration. Here, we aimed to assess the composition of CM from periodontal ligament stem cells (PDLSCs) grown in metformin-preconditioned media (Met-CM) compared to normal PDLSC-CM and assess the ability of Met-CM to recover the function of inflamed PDLSCs. Methods: Met-CM and normal CM were collected from PDLSCs grown with or without 50 µM metformin, respectively, under healthy culture conditions. Mass spectrometry and liquid chromatography–tandem mass spectrometry (LC–MS/MS) were performed to comparatively evaluate the proteomic profiles in PDLSC-CM versus Met-CM. We then treated the PDLSC cultures with lipopolysaccharide (LPS) from Porphyromonas gingivalis to induce inflammation and evaluated the osteogenic/cementogenic differentiation in the presence of Met-CM or normal PDLSC-CM by assessing alkaline phosphatase activity, intracellular calcium levels, and mRNA expression of osteogenic and cementogenic factors, including RUNX2, OCN, OSX, and CEMP-1. Subsequently, we performed RNA sequencing to identify transcriptomic changes in the treated cells. Results: We identified 202 differentially expressed proteins, 175 of which were significant, in Met-CM versus normal PDLSC-CM. Among the analyzed groups, the top three protein classes were protein-binding activity modulator, cytoskeletal protein, and extracellular matrix (ECM) protein. Treatment of PDLSCs with LPS significantly attenuated ALP activity, [Ca²⁺]_i, and the mRNA expression levels of RUNX2, OCN, OSX, and CEMP-1, whereas treatment with Met-CM alone markedly enhanced PDLSC differentiation activity compared with the control. Moreover, osteogenic/cementogenic differentiation of the LPS-treated PDLSCs was recovered through incubation in Met-CM. Transcriptomic analysis identified 511 and 3591 differentially expressed genes in the control versus Met-CM and LPS versus LPS + Met-CM groups, respectively. The enrichment of biological processes includes positive regulation of DNA-templated transcription and skeletal system morphogenesis in the control versus Met-CM comparison, as well as positive regulation of transcription from the RNA polymerase II promoter and negative regulation of the apoptotic process in the LPS versus LPS + Met-CM comparison. Molecular function analysis demonstrated the enrichment of protein-binding terms among the DEGs from each comparison. Conclusions: Metformin preconditioning enhanced the recovery effect of PDLSC-CM on LPS-induced inflamed PDLSCs. These findings suggest that metformin preconditioning could represent a practical formula for PDLSC-secretome, which may contribute to the development of future cell-free periodontal regenerative strategies. Full article

Background/Objectives: Bioactive materials are gaining increased popularity as materials of choice for pulpal regeneration. A similar trend is emerging with root repair materials; however, there is a significant gap in the literature about cementogenic ability of bioceramic repair materials on the periodontal ligament cells. The aim of the present study was to investigate the effect of bioceramic materials (Biodentine and Bio-C Repair) on the cementogenesis potential of the periodontal ligament stem cells (PDLSCs). Methods: PDLSCs were isolated using the enzymatic digestion approach from sound extracted teeth. Material extracts were prepared on rubber discs and immersed in fresh growth medium for 24 h at 37 °C. Reverse transcription–quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression levels of cementogenic markers cementum protein 1 (CEMP1), Cementum attachment protein (CAP), pathway markers transforming growth factor β1(TGF-β1), bone morphogenic protein 2 (BMP2), and inflammatory marker IL-6. Results: Both materials (Biodentine and Bio-C Repair) showed significantly higher gene expressions when compared to the control groups. The gene expression with Bio-C Repair significantly increased when compared with Biodentine, except for TGF-β1 expression, where both materials exhibited similar results. Conclusions: Bio-C Repair demonstrated increased gene expression of cementogenic markers compared to Biodentine under the tested conditions. Further in vivo studies are deemed necessary to translate the findings from this study into clinical practice. Full article

Over the past few years, biomaterial-based periodontal tissue engineering has gained popularity. An ideal biomaterial for treating periodontal defects is expected to stimulate periodontal-derived cells, allowing them to contribute most efficiently to tissue reconstruction. The present study focuses on evaluating the in vitro behavior of human periodontal ligament-derived stromal cells (hPDL-MSCs) when cultured on gelatin/Polycaprolactone prototype (GPP) and volume-stable collagen matrix (VSCM). Cells were cultured onto the GPP, VSCM, or tissue culture plate (TCP) for 3, 7, and 14 days. Cell morphology, adhesion, proliferation/viability, the gene expression of Collagen type I, alpha1 (COL1A1), Vascular endothelial growth factor A (VEGF-A), Periostin (POSTN), Cementum protein 1 (CEMP1), Cementum attachment protein (CAP), Interleukin 8 (IL-8) and Osteocalcin (OCN), and the levels of VEGF-A and IL-8 proteins were investigated. hPDL-MSCs attached to both biomaterials exhibited a different morphology compared to TCP. GPP exhibited stronger capabilities in enhancing cell viability and metabolic activity compared to VSCM. In most cases, the expression of all investigated genes, except POSTN, was stimulated by both materials, with GPP having a superior effect on COL1A1 and VEGF-A, and VSCM on OCN. The IL-8 protein production was slightly higher in cells grown on VSCM. GPP also exhibited the ability to absorb VEGF-A protein. The gene expression of POSTN was promoted by GPP and slightly suppressed by VSCM. In summary, our findings indicate that GPP electrospun nanofibers effectively promote the functional performance of PDLSCs in periodontal regeneration, particularly in the periodontal ligament and cementum compartment. Full article

Separating stars enriched in the s- and r-processes of nucleosynthesis is usually achieved by analyzing the element ratios of s-process elements (like Ba or La) to r-process elements (like Eu). The situation becomes more complex when analyzing CEMP-rs stars, which are carbon-enriched metal-poor objects enriched in a mixture of s- and r-elements. These objects, possibly resulting from the i-process of nucleosynthesis, are notoriously difficult to classify based on elemental ratios. Recent theoretical studies have outlined, however, that the s-, i-, and r-processes produce distinct isotopic mixtures. Here, we propose to analyze a sample of stars known to be enriched in s, r, or r + s elements and to determine the odd-to-even isotopic ratio measured on atomic lines of barium, in order to validate or disprove their assignation. Full article

Type 2 diabetes mellitus (T2DM) represents a significant health problem globally and is linked to a number of complications such as cardiovascular disease, bone fragility and periodontitis. Autologous bone marrow mesenchymal stem cells (BM-MSCs) are a promising therapeutic approach for bone and periodontal regeneration; however, the effect of T2DM on the expression of osteogenic and periodontal markers in BM-MSCs is not fully established. Furthermore, the effect of the presence of comorbidities such as diabetes and osteoarthritis on BM-MSCs is also yet to be investigated. In the present study, BM-MSCs were isolated from osteoarthritic knee joints of diabetic and nondiabetic donors. Both cell groups were compared for their clonogenicity, proliferation rates, MSC enumeration and expression of surface markers. Formation of calcified deposits and expression of osteogenic and periodontal markers were assessed after 1, 2 and 3 weeks of basal and osteogenic culture. Diabetic and nondiabetic BM-MSCs showed similar clonogenic and growth potentials along with comparable numbers of MSCs. However, diabetic BM-MSCs displayed lower expression of periostin (POSTN) and cementum protein 1 (CEMP-1) at Wk3 osteogenic and Wk1 basal cultures, respectively. BM-MSCs from T2DM patients might be suitable candidates for stem cell-based therapeutics. However, further investigations into these cells’ behaviours in vitro and in vivo under inflammatory environments and hyperglycaemic conditions are still required. Full article

Biotechnology and artificial intelligence have sparked a revolution in dentistry, with a focus on restoring natural tissue functions. This transformation has given rise to bioactive materials, inspired by biomimetics, aimed at replicating the processes found in nature. As synthetic biology advances, there is a heightened focus on signaling systems crucial for bio-based diagnostics and therapeutics. Dentistry now harnesses synthetic proteins for tissue regeneration and dental material enhancement. A current research priority is bacterial biofilm inhibition, vital for dental health. Given the role of Streptococcus mutans in dental caries, the development of synthetic antimicrobial peptides targeting this bacterium is underway. The balance of dental enamel between demineralization and remineralization impacts caries formation. Factors such as the presence of hydroxyapatite and salivary peptides influence enamel health. Recent studies have spotlighted salivary protein-inspired peptides for enhanced remineralization. In the realm of bone regeneration, synthetic proteins like bone morphogenetic proteins (BMP) have been spotlighted, earning FDA approval. Research is currently delving into peptides such as cementum protein 1 peptide (CEMP-1-p1) and parathyroid hormone variants like PTH (1-34), underscoring their potential in advancing dental and bone health. Full article

Prior research generally finds that the Pfizer-BioNTech (BNT162b2) and Moderna (mRNA1273) COVID-19 vaccines provide similar protection against mortality, sometimes with a Moderna advantage due to slower waning. However, most comparisons do not address selection effects for those who are vaccinated and with which vaccine. We report evidence on large selection effects, and use a novel method to control for these effects. Instead of directly studying COVID-19 mortality, we study the COVID-19 excess mortality percentage (CEMP), defined as the COVID-19 deaths divided by non-COVID-19 natural deaths for the same population, converted to a percentage. The CEMP measure uses non-COVID-19 natural deaths to proxy for population health and control for selection effects. We report the relative mortality risk (RMR) for each vaccine relative to the unvaccinated population and to the other vaccine, using linked mortality and vaccination records for all adults in Milwaukee County, Wisconsin, from 1 April 2021 through 30 June 2022. For two-dose vaccinees aged 60+, RMRs for Pfizer vaccinees were consistently over twice those for Moderna, and averaged 248% of Moderna (95% CI = 175%,353%). In the Omicron period, Pfizer RMR was 57% versus 23% for Moderna. Both vaccines demonstrated waning of two-dose effectiveness over time, especially for ages 60+. For booster recipients, the Pfizer–Moderna gap is much smaller and statistically insignificant. A possible explanation for the Moderna advantage for older persons is the higher Moderna dose of 100 μg, versus 30 μg for Pfizer. Younger persons (aged 18–59) were well-protected against death by two doses of either vaccine, and highly protected by three doses (no deaths among over 100,000 vaccinees). These results support the importance of a booster dose for ages 60+, especially for Pfizer recipients. They suggest, but do not prove, that a larger vaccine dose may be appropriate for older persons than for younger persons. Full article

Multiphasic scaffolds that combine different architectural, physical, and biological properties are the best option for the regeneration of complex tissues such as the periodontium. Current developed scaffolds generally lack architectural accuracy and rely on multistep manufacturing, which is difficult to implement for clinical applications. In this context, direct-writing electrospinning (DWE) represents a promising and rapid technique for developing thin 3D scaffolds with controlled architecture. The current study aimed to elaborate a biphasic scaffold using DWE based on two polycaprolactone solutions with interesting properties for bone and cement regeneration. One of the two scaffold parts contained hydroxyapatite nanoparticles (HAP) and the other contained the cementum protein 1 (CEMP1). After morphological characterizations, the elaborated scaffolds were assessed regarding periodontal ligament (PDL) cells in terms of cell proliferation, colonization, and mineralization ability. The results demonstrated that both HAP- and CEMP1-functionalized scaffolds were colonized by PDL cells and enhanced mineralization ability compared to unfunctionalized scaffolds, as revealed by alizarin red staining and OPN protein fluorescent expression. Taken together, the current data highlighted the potential of functional and organized scaffolds to stimulate bone and cementum regeneration. Moreover, DWE could be used to develop smart scaffolds with the ability to spatially control cellular orientation with suitable cellular activity at the micrometer scale, thereby enhancing periodontal and other complex tissue regeneration. Full article

Cell-based therapies using periodontal ligament stromal cells (PDLSC) for periodontal regeneration may represent an alternative source for mesenchymal stromal cells (MSC) to MSC derived from bone marrow (MSC(M)) and adipose tissue (MSC(AT)). We aimed to characterize the osteogenic/periodontal potential of PDLSC in comparison to MSC(M) and MSC(AT). PDLSC were obtained from surgically extracted healthy human third molars, while MSC(M) and MSC(AT) were obtained from a previously established cell bank. Flow cytometry, immunocytochemistry, and cell proliferation analyses provided cellular characteristics from each group. Cells from the three groups presented MSC-like morphology, MSC-related marker expression, and multilineage differentiation capacity (adipogenic, chondrogenic, and osteogenic). In this study, PDLSC expressed osteopontin, osteocalcin, and asporin, while MSC(M) and MSC(AT) did not. Of note, only PDLSC expressed CD146, a marker previously applied to identify PDLSC, and presented higher proliferative potential compared to MSC(M) and MSC(AT). Upon osteogenic induction, PDLSC exhibited higher calcium content and enhanced upregulation of osteogenic/periodontal genes compared to MSC(M) and MSC(AT), such as Runx2, Col1A1 and CEMP-1. However, the alkaline phosphatase activity of PDLSC did not increase. Our findings suggest that PDLSC might be a promising cell source for periodontal regeneration, presenting enhanced proliferative and osteogenic potential compared to MSC(M) and MSC(AT). Full article

COVID-19 vaccines have saved millions of lives; however, understanding the long-term effectiveness of these vaccines is imperative to developing recommendations for booster doses and other precautions. Comparisons of mortality rates between more and less vaccinated groups may be misleading due to selection bias, as these groups may differ in underlying health status. We studied all adult deaths during the period of 1 April 2021–30 June 2022 in Milwaukee County, Wisconsin, linked to vaccination records, and we used mortality from other natural causes to proxy for underlying health. We report relative COVID-19 mortality risk (RMR) for those vaccinated with two and three doses versus the unvaccinated, using a novel outcome measure that controls for selection effects. This measure, COVID Excess Mortality Percentage (CEMP), uses the non-COVID natural mortality rate (Non-COVID-NMR) as a measure of population risk of COVID mortality without vaccination. We validate this measure during the pre-vaccine period (Pearson correlation coefficient = 0.97) and demonstrate that selection effects are large, with non-COVID-NMRs for two-dose vaccinees often less than half those for the unvaccinated, and non-COVID NMRs often still lower for three-dose (booster) recipients. Progressive waning of two-dose effectiveness is observed, with an RMR of 10.6% for two-dose vaccinees aged 60+ versus the unvaccinated during April–June 2021, rising steadily to 36.2% during the Omicron period (January–June, 2022). A booster dose reduced RMR to 9.5% and 10.8% for ages 60+ during the two periods when boosters were available (October–December, 2021; January–June, 2022). Boosters thus provide important additional protection against mortality. Full article

Based on the spectra with high resolution and a high signal-to-noise ratio, we investigate the enrichment history of the s-process element in seven barium (Ba) stars by measuring their Ba odd isotope fraction. It is found that the relative contributions of the s-process to their Ba abundance are $91.4\pm 25.7\%$, $91.4\pm 34.3\%$, $82.9\pm 28.5\%$, $77.1\pm 31.4\%$, and $71.4\pm 37.1\%$ for REJ 0702+129, HD 13611, BD+${80}^{°}670$, HR 5692, and HD 202109, respectively. Our results suggest that these five Ba stars have a prominent s-process signature, which indicates that their heavy elements mainly come from their former AGB companions (now WDs) by mass transfer, while the r-process contribution can naturally be explained by the evolution of the Milky Way. The s-process contribution of BD+${80}^{°}670$ is $51.4\pm 31.4\%$, which is the lowest among our seven sample stars. Considering its lower values of both [Ba/Nd] and [Ba/Eu], we suspect that BD+${68}^{°}1027$ is likely to be a r-rich Ba star and has similar origins to the CEMP-r/s stars. HD 218356 has an unreasonable s-process contribution over $100\%$. Combining its stellar atmospheric parameters and the evolutionary stage, we speculate that HD 218356 is a more evolved extrinsic Ba star, and its massive companion should have the largest s-process efficiency in our samples. Full article

The COVID-19 pandemic has adversely affected all sectors including educational institutions transitioning from face-to-face to hybrid and virtual classes. Partial or full closure of tourism businesses has impacted college students’ jobs within the college and/or outside in the business sector. For a tourism dependent economy such as Maine’s, the impacts of COVID-19 have been severe, including lost job opportunities for students. Several studies have researched the impacts of COVID-19 on the physical, psychological, social, and mental health status of college students; however, few have addressed the impacts on college students’ jobs. Thus, the purpose of this study is to understand how students at the University of Southern Maine (USM) have been impacted in their jobs by COVID-19 and to consider what stakeholders can do to support and rebuild the workforce. A quantitative survey was distributed to all USM undergraduate students (completed by 160) between 26 April through 6 May 2021. The study found that pre-COVID, 44% of student employment was in non-tourism, 25% in tourism, and 16% in USM work study, while 15% were unemployed. At the time of the survey, those proportions had shifted to 42% in non-tourism, 22% in tourism, 14% in USM work study, and 22% not employed with a significant increase in the non-employed student category. The study found that, initially, COVID-19 had impacted student employment in terms of changed responsibilities, reduced hours, job layoffs/losses, increased hours, and voluntary job loss. Students’ current jobs (during the survey) were impacted in the form of changed responsibilities/jobs/locations and industries, including decreased hours. During the pandemic, students valued industry support such as enhanced cleaning/safety, flexible hours/time off, work from home, as well as academic support in terms of flexibility, emotional support, industry updates, and networking opportunities. The study recommends that stakeholders develop collaborative comprehensive emergency management plans (CEMPs) to mitigate disruptions such as COVID-19 and be prepared for future disasters of this nature. Full article