Development of a Deep Learning Algorithm for Periapical Disease Detection in Dental Radiographs

Periapical radiolucencies, which can be detected on panoramic radiographs, are one of the most common radiographic findings in dentistry and have a differential diagnosis including infections, granuloma, cysts and tumors. In this study, we seek to investigate the ability with which 24 oral and maxillofacial (OMF) surgeons assess the presence of periapical lucencies on panoramic radiographs, and we compare these findings to the performance of a predictive deep learning algorithm that we have developed using a curated data set of 2902 de-identified panoramic radiographs. The mean diagnostic positive predictive value (PPV) of OMF surgeons based on their assessment of panoramic radiographic images was 0.69(± 0.13), indicating that dentists on average falsely diagnose 31% of cases as radiolucencies. However, the mean diagnostic true positive rate (TPR) was 0.51(± 0.14), indicating that on average 49% of all radiolucencies were missed. We demonstrate that the deep learning algorithm achieves a better performance than 14 of 24 OMF surgeons within the cohort, exhibiting an average precision of 0.60(± 0.04), and an F1 score of 0.58(± 0.04) corresponding to a PPV of 0.67(± 0.05) and TPR of 0.51(± 0.05). The algorithm, trained on limited data and evaluated on clinically validated ground truth, has potential to assist OMF surgeons in detecting periapical lucencies on panoramic radiographs

Levator anguli oris muscle based flaps for nasal reconstruction following resection of nasal skin tumours

<p>Abstract</p> <p>Background</p> <p>surgical excision remains the best tool for management of skin tumors affecting nasal skin, however many surgical techniques have been used for reconstruction of the nasal defects caused by excisional surgery. The aim of this work is the evaluation of the feasibility and outcome of levator anguli oris muscle based flaps.</p> <p>Methods</p> <p>Ninety patients of malignant nasal skin tumours were included in this study. Age was ranged from four to 78 years. For small unilateral defects affecting only one side ala nasi, levator anguli oris myocautaneous (LAOMC) flap was used in 45 patients. For unilateral compound loss of skin and mucus membrane, levator anguli oris myocautaneous mucosal (LAOMCM) flap was used in 23 patients. Very large defects; bilateral either LAOMC or LAOMCM flaps combined with forehead glabellar flaps were used to reconstruct the defect in 22 patients.</p> <p>Results</p> <p>Wound dehiscence was the commonest complication. Minor complications, in the form of haematoma and minor flap loss were managed conservatively. Partial flap loss was encountered in 6 patients with relatively larger tumours or diabetic co-morbidity, three of whom were required operative re-intervention in the form of debridement and flap refashioning, while total flap loss was not occurred at all.</p> <p>Conclusions</p> <p>Immediate nasal reconstruction for nasal skin and mucosal tumours with levator anguli oris muscle based flaps (LAOMC, LAOMCM) is feasible and spares the patient the psychic trauma due to organ loss.</p

Agpat6 —a novel lipid biosynthetic gene required for triacylglycerol production in mammary epithelium

In analyzing the sequence tags for mutant mouse embryonic stem (ES) cell lines in BayGenomics (a mouse gene-trapping resource), we identified a novel gene, Agpat6, with sequence similarities to previously characterized glycerolipid acyltransferases. Agpat6’s closest family member is another novel gene that we have provisionally designated Agpat8. Both Agpat6 and Agpat8 are conserved from plants, nematodes, and flies to mammals. AGPAT6, which is predicted to contain multiple membrane-spanning helices, is found exclusively within the endoplasmic reticulum in mammalian cells. To gain insights into the in vivo importance of Agpat6, we used the Agpat6 ES cell line from BayGenomics to create Agpat6-deficient (Agpat6−/−) mice. Agpat6−/− mice lacked full-length Agpat6 transcripts, as judged by northern blots. One of the most striking phenotypes of Agpat6−/− mice was a defect in lactation. Pups nursed by Agpat6−/− mothers die perinatally. Normally, Agpat6 is expressed at high levels in the mammary epithelium of breast tissue, but not in the surrounding adipose tissue. Histological studies revealed that the aveoli and ducts of Agpat6−/− lactating mammary glands were underdeveloped, and there was a dramatic decrease in size and number of lipid droplets within mammary epithelial cells and ducts. Also, the milk from Agpat6−/− mice was markedly depleted in diacylglycerols and triacylglycerols. Thus, we identified a novel glycerolipid acyltransferase of the endoplasmic reticulum, AGPAT6, which is crucial for the production of milk fat by the mammary gland

Sprouty Proteins Inhibit Receptor-mediated Activation of Phosphatidylinositol-specific Phospholipase C

PLCγ03B3 binds Spry1 and Spry2. Overexpression of Spry decreased PLCγ03B3 activity and IP3 and DAG production, whereas Spry-deficient cells yielded more IP3. Spry overexpression inhibited T-cell receptor signaling and Spry1 null T-cells hyperproliferated with TCR ligation. Through action of PLCγ03B3, Spry may influence signaling through multiple receptors

Femtosecond fluorescence studies of Auramine O in hybrid sol-gel derived films

Femtosecond fluorescence upconversion experiments have been performed on Auramine 0 (a diphenylmethane dye) in polymethylmethacrylate (PMMA) and in hybrid organic/inorganic sol-gel based films. All the investigated samples showed a fast decay (few picoseconds) and a long decay (hundreds of picoseconds). The fast components are representative of the rapid cooling of the excess excitation energy to the matrices. The long components are representative of the excited-state lifetime of the probed molecules. Auramine 0 in solid matrices showed lifetimes longer than in liquid solutions. Torsional diffusion motions of the two phenyl rings of the molecule are held responsible for the excited-state dynamics. A dynamic Stokes shift has been observed for all samples. The lack of a rise time when detection was on the red side is explained in terms of an adiabatic coupling between emissive and nonemissive excited states, as is the case of liquid solutions. Different spectral shifts in PMMA and hybrid glasses have been measured. A different coupling between the emissive and nonemissive excited states for the two types of matrices is considered

Femtosecond fluorescence studies of Auramine O in hybrid sol-gel derived films

Femtosecond fluorescence upconversion experiments have been performed on Auramine 0 (a diphenylmethane dye) in polymethylmethacrylate (PMMA) and in hybrid organic/inorganic sol-gel based films. All the investigated samples showed a fast decay (few picoseconds) and a long decay (hundreds of picoseconds). The fast components are representative of the rapid cooling of the excess excitation energy to the matrices. The long components are representative of the excited-state lifetime of the probed molecules. Auramine 0 in solid matrices showed lifetimes longer than in liquid solutions. Torsional diffusion motions of the two phenyl rings of the molecule are held responsible for the excited-state dynamics. A dynamic Stokes shift has been observed for all samples. The lack of a rise time when detection was on the red side is explained in terms of an adiabatic coupling between emissive and nonemissive excited states, as is the case of liquid solutions. Different spectral shifts in PMMA and hybrid glasses have been measured. A different coupling between the emissive and nonemissive excited states for the two types of matrices is considered

Retardation of orientation relaxation of azo-dye doped amorphous polymers upon all-optical poling

The orientation relaxation of azo-dyes upon all-optical poling was studied. Azo-dye doped amorphous polymers were poled for different durations by all-optical poling at several temperatures. A quasi-permanent macroscopic second-order nonlinear optical susceptibility chi((2)) was inscribed in the dye-doped centrosymmetric polymer systems. Relaxation of the chi((2)) was monitored by second harmonic generation. It shows that the polar orientation relaxation follows the duration of the poling process: the longer the poling, the slower the polar relaxation time. Causes of the orientation relaxation retardation are discussed. (c) 2006 Elsevier B.V. All rights reserved