Machine Learning to Predict Apical Lesions: A Cross-Sectional and Model Development Study

(1) Background: We aimed to identify factors associated with the presence of apical lesions (AL) in panoramic radiographs and to evaluate the predictive value of the identified factors. (2) Methodology: Panoramic radiographs from 1071 patients (age: 11–93 a, mean: 50.6 a ± 19.7 a) with 27,532 teeth were included. Each radiograph was independently assessed by five experienced dentists for AL. A range of shallow machine learning algorithms (logistic regression, k-nearest neighbor, decision tree, random forest, support vector machine, adaptive and gradient boosting) were employed to identify factors at both the patient and tooth level associated with AL and to predict AL. (3) Results: AL were detected in 522 patients (48.7%) and 1133 teeth (4.1%), whereas males showed a significantly higher prevalence than females (52.5%/44.8%; p < 0.05). Logistic regression found that an existing root canal treatment was the most important risk factor (adjusted Odds Ratio 16.89; 95% CI: 13.98–20.41), followed by the tooth type ‘molar’ (2.54; 2.1–3.08) and the restoration with a crown (2.1; 1.67–2.63). Associations between factors and AL were stronger and accuracy higher when using fewer complex models like decision tree (F1 score: 0.9 (0.89–0.9)). (4) Conclusions: The presence of AL was higher in root-canal treated teeth, those with crowns and molars. More complex machine learning models did not outperform less-complex ones

Synthesis, characterization and DNA cleavage activity of nickel(II) adducts with aromatic heterocyclic bases

Mixed ligand complexes of nickel(II) with 2,4-dihydroxyaceto-phenone oxime (DAPO) and 2,4-dihydroxybenzophenone oxime (DBPO) as primary ligands, and pyridine (Py) and imidazole (Im) as secondary ligands were synthesized and characterized by molar conductivity, magnetic moments measurements, as well as by electronic, IR, and 1H-NMR spectroscopy. Electrochemical studies were performed by cyclic voltammetry. The active signals are assignable to the NiIII/II and NiII/I redox couples. The binding interactions between the metal complexes and calf thymus DNA were investigated by absorption and thermal denaturation. The cleavage activity of the complexes was determined using double-stranded pBR322 circular plasmid DNA by gel electrophoresis. All complexes showed increased nuclease activity in the presence of the oxidant H2O2. The nuclease activities of mixed ligand complexes were compared with those of the parent copper(II) complexes

Efficiency of biofilm removal by combination of water jet and cold plasma: an in-vitro study

Background: Peri-implantitis therapy is a major problem in implantology. Because of challenging rough implant surface and implant geometry, microorganisms can hide and survive in implant microstructures and impede debridement. We developed a new water jet (WJ) device and a new cold atmospheric pressure plasma (CAP) device to overcome these problems and investigated aspects of efficacy in vitro and safety with the aim to create the prerequisites for a clinical pilot study with these medical devices. Methods: We compared the efficiency of a single treatment with a WJ or curette and cotton swab (CC) without or with adjunctive use of CAP (WJ + CAP, CC + CAP) to remove biofilm in vitro from rough titanium discs. Treatment efficacy was evaluated by measuring turbidity up to 72 h for bacterial re-growth or spreading of osteoblast-like cells (MG-63) after 5 days with scanning electron microscopy. With respect to application safety, the WJ and CAP instruments were examined according to basic regulations for medical devices. Results: After 96 h of incubation all WJ and CC treated disks were turbid but 67% of WJ + CAP and 46% CC + CAP treated specimens were still clear. The increase in turbidity after WJ treatment was delayed by about 20 h compared to CC treatment. In combination with CAP the cell coverage significantly increased to 82% (WJ + CAP) or 72% (CC + CAP), compared to single treatment 11% (WJ) or 10% (CC). Conclusion: The newly developed water jet device effectively removes biofilm from rough titanium surfaces in vitro and, in combination with the new CAP device, biologically acceptable surfaces allow osteoblasts to grow. WJ in combination with CAP leads to cleaner surfaces than the usage of curette and cotton swabs with or without subsequent plasma treatment. Our next step will be a clinical pilot study with these new devices to assess the clinical healing process

Enzymatic Depilation of Animal Hide: Identification of Elastase (LasB) from Pseudomonas aeruginosa MCM B-327 as a Depilating Protease

Conventional leather processing involving depilation of animal hide by lime and sulphide treatment generates considerable amounts of chemical waste causing severe environmental pollution. Enzymatic depilation is an environmentally friendly process and has been considered to be a viable alternative to the chemical depilation process. We isolated an extracellular protease from Pseudomonas aeruginosa strain MCM B-327 with high depilation activity using buffalo hide as a substrate. This 33 kDa protease generated a peptide mass fingerprint and de novo sequence that matched perfectly with LasB (elastase), of Pseudomonas aeruginosa. In support of this data a lasB mutant of MCM B-327 strain lacked depilatory activity and failed to produce LasB. LasB heterologously over-produced and purified from Escherichia coli also exhibited high depilating activity. Moreover, reintroduction of the lasB gene to the P. aeruginosa lasB mutant via a knock-in strategy also successfully restored depilation activity thus confirming the role of LasB as the depilating enzyme

Ballistic impact crater modelling using UAV and structure from motion technology : 2012 Te Maari volcanic eruptions, New Zealand

New Zealand has a strong historical background of producing volcanic eruptions and earthquakes due to its geographical setting. The deformation caused by the collision of Australian and Pacific plates has given rise to New Zealand’s volcanism. Most of NZ’s volcanism has occurred in the Taupo Volcanic Zone (TVZ) in the last 1.6 million years. On 6th August 2012, Upper Te Maari volcanic eruptions occurred on the north-eastern flanks of Tongariro volcano complex, in TVZ region producing a hazard from volcanic ballistic projectiles. The vulnerability of people walking along the Tongariro Alpine Crossing to ballistic impacts was identified by (Fitzgerald, 2014) and the hazard was calculated by remote and field mapping of ballistic craters. This project examines the effectiveness and accuracy of mapping a volcanic crater field near Tongariro, using a Draganfly X4P un-manned aerial vehicle (UAV). The UAV is flown at different elevations above the ground surface to capture the two-dimensional ground images. The UAV imagery datasets and ground truthing survey points are incorporated to Agisoft Photoscan Pro software to build a three-dimensional elevation model, using Structure from motion (SfM) and photogrammetry technology. The use of UAV’s and SfM to study geohazards is a new concept which could prove an alternative to the more expensive Light Detection and Ranging (LiDAR) surveys. The digital elevation models (DEMs) developed in SfM photogrammetric software were used to identify volcanic craters within a 100 m2 survey site selected for this project. A model was built using six different parameters, to distinguish volcanic craters from natural depressions on the ground surface. The UAV’s imagery resolution, altitude of the flight and other atmospheric factors play a crucial role to the accuracy of the results. A total of 135 volcanic craters were identified with 118 pixels per centimetre (ppcm), when the UAV was flown at 40m altitude above the ground surface. When the resolution of images was reduced to 70 ppcm manually, only 101 volcanic craters could be identified successfully. A LiDAR is a remote sensing method used to measure variable distances to the Earth that uses near infrared pulsed laser to map the topographic land surface. A LiDAR and aerial imagery survey was first conducted by NZ Aerial Mapping in November 2012, three months after the 2012 Te Maari volcanic eruptions. Out of the total 3587 volcanic craters yielded from LiDAR and orthophoto analysis, 107 craters fall within the 100 m2 survey site chosen in for this project (Fitzgerald, 2014).The UAV and SfM modelling identified more craters (135) four years post 2012 Te Maari eruptions. This thesis found that UAV’s are both feasible and cost-effective when used in this context; however, the major limiting factor is the small area covered by a UAV when compared to LiDAR surveys. Hence, the SfM and UAV technology can therefore be used at localized sites to achieve maximized results with cost effective measures, when compared to conducting LiDAR surveys

Epidemiology of diabetic disorders and its long-term impact on adiposity in the offspring

Obesity and diabetes have reached epidemic proportions and have emerged as massive public health problems globally. The etiology of both obesity and diabetes are related, multifactorial, highly complex, and involves interplay of genetic, environmental, socio-economic and physiological factors, which calls for a more extensive research in understanding the risk factors and biological pathways. Hence, this dissertation contributed in part to understanding the role of iron markers in the development of type 2 diabetes mellitus and the role of intrauterine hyperglycemia in influencing the risk of offspring obesity along with investigating potential pathways. In the first part of my dissertation, the associations of iron markers (ferritin and transferrin) with type 2 diabetes mellitus and metabolic syndrome were investigated using the population-based Study of Health in Pomerania. The present analyses were based on 3,232 participants aged 20-81 years with a follow-up time of nearly 11 years. The results suggest that serum ferritin concentrations were associated with a higher prevalence of type 2 diabetes mellitus and metabolic syndrome in the total population as well as in men. However, the effects of serum ferritin on incident type 2 diabetes mellitus were observed only in women, while the effects on incident metabolic syndrome were seen in the total population. Serum ferritin is also known to reflect systemic inflammation or hepatic dysfunction in addition to increased iron stores. Hence, upon further analyses, the associations were found to be attenuated after adjustment for hepatic enzymes but not after adjustment for inflammation. Transferrin was not associated with any of the outcomes. Thus, our study provides evidence for a link between the iron marker ferritin and type 2 diabetes mellitus and metabolic syndrome, although the association seemed to vary by sex. Moreover, hepatic dysfunction seems likely to be in the pathway between ferritin and type 2 diabetes mellitus and metabolic syndrome. In the second part of my dissertation, the association between maternal hyperglycemia and the risk of offspring overweight and obesity were investigated using three different cohorts: TEDDY, TEENDIAB and BABYDIAB/BABYDIET. The present analyses were based on a total of 8,103 children who were followed until 6 years of age in TEDDY study and until 18 years of age in TEENDIAB and BABYDIAB/BABYDIET studies. The dissertation revealed that maternal hyperglycemia in general may be associated with increased risk for childhood overweight and obesity, and that the association gets stronger as children grow older, with the risk being clearly evident at late childhood and adolescence. Moreover, this dissertation adds that this association can be driven by different pathways based on the type of maternal diabetes to which the offspring was exposed. The association of maternal gestational diabetes mellitus with offspring overweight can be largely explained by the confounding influence of maternal BMI, whereas the association of maternal type 1 diabetes mellitus with offspring overweight can be substantially explained by birthweight in all three studies. In our attempt to understand biological pathways at a cellular level, we found that the offspring metabolome was unlikely to be in the causal pathway between maternal type 1 diabetes mellitus and overweight, because this association could not be explained by any of the potentially relevant metabolites. To conclude, this dissertation acknowledges the fact that prevention and early intervention of obesity and diabetes is of paramount importance to lessen the impact of these public health problems. Thus, our findings of the role of ferritin in increasing the risk of type 2 diabetes mellitus/ metabolic syndrome and the role of intrauterine hyperglycemia in increasing the risk of offspring overweight helped to identify particular risk groups who may need closer attention with respect to prevention of obesity and diabetes.Adipositas und Diabetes haben epidemische Ausmaße angenommen und sich weltweit zu einem massiven Problem der öffentlichen Gesundheit entwickelt. Die Ätiologie von Adipositas und Diabetes ist verwandt, multifaktoriell, hochkomplex und beinhaltet ein Zusammenspiel von genetischen, umweltbedingten, sozioökonomischen und physiologischen Faktoren, was eine umfassendere Forschung zum Verständnis der Risikofaktoren und biologischen Pfade erfordert. Daher trug diese Dissertation zum Teil dazu bei, die Rolle von Eisenmarkern bei der Entwicklung von Typ-2-Diabetes mellitus und die Rolle der intrauterinen Hyperglykämie bei der Beeinflussung des Risikos von Adipositas bei den Nachkommen zu verstehen und mögliche Pfade zu untersuchen. Im ersten Teil meiner Dissertation wurden die Assoziationen von Eisenmarkern (Ferritin und Transferrin) mit Typ-2-Diabetes mellitus und metabolischem Syndrom anhand der bevölkerungsbasierten Studie (Study of Health in Pomerania) untersucht. Die Analysen basierten auf 3.232 Teilnehmern im Alter von 20-81 Jahren mit einer Nachbeobachtungszeit von fast 11 Jahren. Die Ergebnisse deuten darauf hin, dass die Ferritin konzentration im Serum sowohl in der Gesamtbevölkerung als auch bei Männern mit einer höheren Prävalenz von Diabetes mellitus Typ 2 und metabolischem Syndrom assoziiert ist. Die Auswirkungen von Serum ferritin auf das Auftreten von Typ-2-Diabetes mellitus wurden jedoch nur bei Frauen beobachtet, während die Auswirkungen auf das Auftreten des metabolischen Syndroms in der Gesamtbevölkerung zu beobachten waren. Es ist bekannt, dass Serum ferritin neben erhöhten Eisenspeichern auch systemische Entzündungen oder hepatische Funktionsstörungen widerspiegelt. Daher wurde bei weiteren Analysen festgestellt, dass die Assoziationen nach Adjustierung für Leberenzyme, nicht aber nach Adjustierung für Entzündungen abgeschwächt wurden. Transferrin war mit keinem der Ergebnisse assoziiert. Unsere Studie liefert somit Beweise für einen Zusammenhang zwischen dem Eisenmarker Ferritin und Typ-2-Diabetes mellitus sowie dem metabolischen Syndrom, obwohl die Assoziation je nach Geschlecht zu variieren scheint. Darüber hinaus scheint eine Leberfunktionsstörung wahrscheinlich in den Zusammenhang zwischen Ferritin und Typ-2-Diabetes mellitus und metabolischem Syndrom eingebunden zu sein. Im zweiten Teil meiner Dissertation wurde der Zusammenhang zwischen mütterlicher Hyperglykämie und dem Risiko von Übergewicht und Adipositas bei den Nachkommen anhand von drei verschiedenen Kohorten TEDDY, TEENDIAB und BABYDIAB/BABYDIET untersucht. Die Analysen basierten auf insgesamt 8.103 Kindern, die in der TEDDY-Studie bis zum Alter von 6 Jahren und in den Studien TEENDIAB und BABYDIAB/BABYDIET bis zum Alter von 18 Jahren verfolgt wurden. Aus der Dissertation geht hervor, dass eine mütterliche Hyperglykämie im Allgemeinen mit einem erhöhten Risiko für Übergewicht und Adipositas im Kindesalter verbunden sein kann und dass sich dieser Zusammenhang mit zunehmendem Alter der Kinder verstärkt, wobei das Risiko in der späten Kindheit und im Jugendalter deutlich erkennbar ist. Darüber hinaus wird in dieser Dissertation festgestellt, dass dieser Zusammenhang je nach Art des mütterlichen Diabetes, dem die Nachkommen ausgesetzt waren, auf unterschiedlichen Wegen zustande kommen kann. Der Zusammenhang zwischen mütterlichem Gestationsdiabetes mellitus und Übergewicht der Nachkommen kann weitgehend durch den störenden Einfluss des mütterlichen BMI erklärt werden, während der Zusammenhang zwischen mütterlichem Typ-1-Diabetes mellitus und Übergewicht der Nachkommen in allen drei Studien im Wesentlichen durch das Geburtsgewicht erklärt werden kann. Bei unserem Versuch, biologische Pfade auf zellulärer Ebene zu verstehen, haben wir festgestellt, dass das Metabolom der Nachkommen wahrscheinlich nicht in den kausalen Pfad zwischen mütterlichem Typ-1-Diabetes mellitus und Übergewicht eingebunden ist, da dieser Zusammenhang durch keinen der potenziell relevanten Metaboliten erklärt werden konnte. Zusammenfassend lässt sich sagen, dass diese Dissertation die Tatsache anerkennt, dass Prävention und frühzeitige Intervention bei Adipositas und Diabetes von größter Bedeutung sind, um die Auswirkungen dieser Probleme auf die öffentliche Gesundheit zu verringern. Unsere Erkenntnisse über die Rolle von Ferritin bei der Erhöhung des Risikos für Typ-2-Diabetes mellitus/metabolisches Syndrom und die Rolle der intrauterinen Hyperglykämie bei der Erhöhung des Risikos für Übergewicht bei den Nachkommen haben dazu beigetragen, bestimmte Risikogruppen zu identifizieren, die im Hinblick auf die Prävention von Adipositas und Diabetes mehr Aufmerksamkeit benötigen

In vivo validation of near-infrared light transillumination for interproximal dentin caries detection.

OBJECTIVES The aims of this clinical study were to investigate the diagnostic accuracy of near-infrared light transillumination (NILT) as a novel X-ray-free method for proximal dentin caries detection and to compare this method to established diagnostic methods. MATERIALS AND METHODS A total of 127 interproximal dentin caries lesions without any cavity within visible dentin in posterior teeth from 85 consecutively selected patients were included. Visual and radiographic diagnoses and laser fluorescence measurements were available. NILT images were obtained, and a dentin lesion was predicted if a demineralisation involved the enamel-dentin junction (NILT-EDJ) or a shadow in dentin was detectable (NILT-dentin). Included lesions were opened and validated (reference standard). The statistical analyses included descriptive analyses and calculations of sensitivity, specificity and Az values. RESULTS The diagnostic accuracy with respect to the reference standard was 1.6% for visual inspection, 66.7% for laser fluorescence, 96.1% for digital radiography, 29.1% for NILT-dentin and 99.2% for NILT-EDJ. Bitewings (Az 0.984) and NILT-EDJ (Az 0.992) performed equally. CONCLUSION Given the lack of true negatives in the study, the diagnostic accuracy of NILT achieved the same level as bitewings for the detection of proximal dentin caries. CLINICAL RELEVANCE This study might indicate that NILT could reduce the usage of bitewings